System for generating nitric oxide

Abstract

The present disclosure provides a system for generating nitric oxide. The system includes an apparatus for generating nitric oxide, the apparatus comprising: a reaction chamber having a liquid region and a gas region, the liquid region configured to house a reaction medium, the gas region configured to house a product gas comprising nitric oxide; a plurality of electrodes and a sparger disposed in the reaction medium; an energy source electrically connected to the plurality of electrodes and configured to apply a predetermined voltage or a predetermined current to the cathode to generate the nitric oxide; an inlet circuit in fluid communication with the sparger and configured to deliver a carrier gas to the sparger; an outlet circuit in fluid communication with the gas region of the reaction chamber and configured to deliver the product gas from the reaction chamber; a pressure vessel in fluid communication with the outlet circuit, the pressure vessel configured to receive the product gas from the outlet circuit, store the received product gas at or below a predetermined pressure, and release the received product gas.

Description

[0001] This application is a divisional application of patent application number CN202180027930.4 (the original application was filed on December 17, 2021, and the invention was entitled "Apparatus, System and Method for Generating Nitric Oxide").

[0002] Cross-references to related applications

[0003] This application claims Chinese patent applications filed on December 18, 2020: No. 202011502839.7, No. 202011502846.7, No. 202011502862.6, No. 202011508948.X, No. 202023064800.X, and No. 202023064847.6. The priority rights of Chinese patent applications No. 202023064866.9, No. 202023072485.5, No. 202023072503.X, No. 202110183873.0, No. 202120353644.4, and No. 202120353650.X, filed on December 18, 2020, and February 8, 2021, respectively, are hereby incorporated herein by reference in their entirety. Technical Field

[0004] This disclosure relates to apparatus, systems and methods for generating and / or delivering nitric oxide, and more particularly to systems for generating and / or delivering nitric oxide as needed. Background Technology

[0005] Nitric oxide (NO) is a gaseous signaling molecule that plays an important role in many physiological and pathological processes. NO can diffuse across the cell membrane without intermediate transport mechanisms, thus signaling neighboring cells or tissues efficiently and rapidly. For example, NO produced by vascular endothelial cells can signal relaxation to surrounding vascular smooth muscle, leading to vasodilation and increased blood flow. NO may also be involved in electron transfer and redox reactions in human cellular biochemical events. NO can induce various physiological effects, such as endothelium-dependent vasodilation, by activating guanylate cyclase.

[0006] Inhaled NO can improve the body's oxidative capacity and reduce the need for high-risk extracorporeal cardiopulmonary support in critically ill patients. Controlled administration of appropriate amounts of inhaled NO can reduce pulmonary hypertension and improve oxygenation. The U.S. Food and Drug Administration has approved inhaled NO as a medication for the treatment of persistent pulmonary hypertension in newborns. NO inhalation therapy is also used in various disease and clinical fields, such as neonatal respiratory distress, critical care medicine, cardiothoracic surgery, acute respiratory distress, and anesthesiology.

[0007] In clinical settings, high-pressure gas cylinders or tanks are used to supply NO. These cylinders are large and heavy, and are typically mounted on wheeled delivery vehicles or trolleys, often placed beside beds in crowded intensive care units. Using such heavy and bulky cylinders can pose safety risks to patients and healthcare workers. For example, patients and healthcare workers may be exposed to toxic nitrogen dioxide formed during system setup or due to potential NO leaks from damaged controllers, valves, or supply lines. Healthcare workers may also suffer physical injury from moving or replacing cylinders. Therefore, there is a need to overcome and / or address one or more of these disadvantages. This disclosure relates to a cylinder-free or "canister-less" system and method that can generate NO on demand without requiring the storage of large quantities of pressurized NO. Summary of the Invention

[0008] According to some embodiments of this disclosure, a system for generating nitric oxide is provided, the system comprising an apparatus for generating nitric oxide, the apparatus comprising: a reaction chamber having a liquid region and a gas region, the liquid region being configured to contain a reaction medium, the gas region being configured to contain a product gas including nitric oxide; a plurality of electrodes disposed in the reaction medium, the plurality of electrodes including cathodes; an energy source electrically connected to the plurality of electrodes and configured to apply a predetermined voltage or a predetermined current to the cathode to generate nitric oxide; a sprayer disposed in the reaction medium; an inlet circuit fluidly connected to the sprayer and configured to deliver a carrier gas to the sprayer; and an outlet circuit fluidly connected to the gas region of the reaction chamber and configured to deliver the product gas from the reaction chamber; and a pressure vessel fluidly connected to the outlet circuit, the pressure vessel being configured to receive the product gas from the outlet circuit, store the received product gas at or below a predetermined pressure, and release the received product gas.

[0009] It should be understood that the foregoing general description and the following detailed description are merely exemplary and explanatory, and do not limit the claimed disclosed embodiments.

[0010] The accompanying drawings form part of this specification. The drawings illustrate several embodiments of this disclosure, and together with the description, serve to explain the principles of certain disclosed embodiments as set forth in the appended claims. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of a NO system according to some embodiments of the present disclosure.

[0012] Figure 2 This is a schematic diagram of a NO generation apparatus according to some embodiments of the present disclosure.

[0013] Figure 3A This is a schematic diagram of a first electrode, a second electrode, and a sprayer according to some embodiments of the present disclosure.

[0014] Figure 3B This is a perspective view of a sprayer according to some embodiments of the present disclosure.

[0015] Figure 4A This is a graphical representation of the concentration of NO in the product gas generated by the NO generating apparatus according to some embodiments of the present disclosure and the current applied to the electrode.

[0016] Figure 4B This is a graphical representation of the change in NO concentration over time in the product gas generated by a NO generating apparatus according to some embodiments of the present disclosure.

[0017] Figure 4C This is a graphical representation of the concentration of NO in the product gas generated by the NO generating apparatus during multiple stages according to some embodiments of the present disclosure.

[0018] Figure 5A This is an exploded view of a filtering device according to some embodiments of the present disclosure.

[0019] Figure 5B yes Figure 5A A cross-sectional perspective view of the filtration device.

[0020] Figure 5C yes Figure 5A A cross-sectional view of the filtration device.

[0021] Figure 6A This is a perspective view of a pressure vessel according to some embodiments of the present disclosure.

[0022] Figure 6B yes Figure 6A A cross-sectional perspective view of a pressure vessel.

[0023] Figure 6C yes Figure 6A Another cross-sectional view of the pressure vessel.

[0024] Figure 7A This is a top perspective view of an exhaust gas treatment apparatus according to some embodiments of the present disclosure.

[0025] Figure 7B yes Figure 7A A bottom-view perspective view of the waste gas treatment device.

[0026] Figure 7C yes Figure 7A Cross-sectional view of the waste gas treatment device.

[0027] Figure 8A This is an exploded view of a gas converter according to some embodiments of the present disclosure.

[0028] Figure 8B This is a schematic diagram of a gas converter according to some embodiments of the present disclosure.

[0029] Figure 9 This is a schematic diagram of a ventilation circuit for delivering NO to a patient according to some embodiments of the present disclosure.

[0030] Figure 10A This is a perspective view of a moisture collector according to some embodiments of the present disclosure.

[0031] Figure 10B yes Figure 10A A partial perspective view of the water collector.

[0032] Figure 10C yes Figure 10A Another partial perspective view of the water collector.

[0033] Figure 11A This is a schematic diagram of the sampling process of a gas monitoring device according to some embodiments of the present disclosure.

[0034] Figure 11B This is a schematic diagram of the initialization process of a gas monitoring device according to some embodiments of the present disclosure.

[0035] Figure 11C This is a schematic diagram of the cleaning process of a gas monitoring device according to some embodiments of the present disclosure.

[0036] Figure 11D This is a schematic diagram of the calibration process of a gas monitoring device according to some embodiments of the present disclosure.

[0037] Figure 12 This is a flowchart illustrating a NO generation method according to some embodiments of the present disclosure. Detailed Implementation

[0038] The disclosed embodiments will now be described in detail with reference to the accompanying drawings. Unless otherwise defined, technical or scientific terms have the meanings commonly understood by one of ordinary skill in the art. The disclosed embodiments have been described in sufficient detail to enable one of ordinary skill in the art to practice them. It should be understood that other embodiments may be utilized and changes may be made without departing from the scope of the disclosed embodiments. Therefore, the materials, methods, and examples are illustrative only and are not intended to be limiting.

[0039] This disclosure provides apparatus, systems, and methods for generating NO from one or more electrochemical reactions. According to one aspect of this disclosure, embodiments can output a product gas comprising NO. NO in the product gas can be generated or delivered at a predetermined concentration and / or flow rate. For example, some embodiments can output a product gas with clinically relevant concentrations and / or flow rates of NO for inhaled NO therapy. The concentration and / or flow rate of NO in the product gas can be adjusted. For example, the concentration of NO in the product gas can be in the range of about 0 to about 20,000 ppm.

[0040] The dimensionless unit "ppm" used in this disclosure to describe gas concentration refers to parts per million of volume and can be converted to other concentration units, such as parts per million of moles or milligrams per liter (mg / L). The dimensionless unit "%" or "volume %" used in this disclosure to describe gas concentration refers to volume percentage and can be converted to other concentration units, such as weight percentage or molar concentration. As used herein, "about" in a numerical range indicates that the range covers normal industry and subject matter variations or tolerances used in manufacturing and / or operation. As used herein, the phrases "less than," "greater than," "between one value and another," or "from one value to another" in a numerical range include all values ​​at and within or between endpoints.

[0041] According to another aspect of this disclosure, embodiments may allow NO to be generated in a phase comprising at least one operating cycle. During the operating cycle, the concentration and / or flow rate of NO in the product gas may reach and / or remain at a steady state. As described herein, the concentration and / or flow rate of NO in the product gas at steady state may deviate from a certain value or range due to steady-state error. For example, the steady-state error may be in the range of approximately 0 to approximately 10%. The operating cycle may, for example, last for up to approximately 60 hours or longer.

[0042] According to another aspect of this disclosure, embodiments may allow NO generation in a phase including at least one ramp cycle. As described herein, a ramp cycle can refer to a transition period in which the NO concentration of the product gas increases or decreases from an initial concentration to a predetermined steady-state concentration. The ramp cycle can be a ramp-up cycle or a ramp-down cycle. For example, the ramp cycle can range from approximately 2 minutes to approximately 10 minutes. The ramp cycle can be predetermined or adjusted to allow for a more rapid or immediate delivery of a stable NO flow, as may be necessary in intensive care units.

[0043] According to another aspect of this disclosure, embodiments may allow NO to be generated in multiple stages. Multiple stages of NO generation can provide NO to treat the same patient or different patients over time. One or more parameters for generating or delivering NO through some embodiments of the invention may be predetermined and / or adjusted. For example, the number of stages, the number of operating cycles within a stage, the start and / or end times of operating cycles, and / or the concentration and / or flow rate of NO in the product gas during the operating cycle of a stage may be predetermined and / or adjusted.

[0044] According to another aspect of this disclosure, in order to reduce exposure to health risks, embodiments may reduce or remove one or more toxic impurities, such as nitrogen dioxide, that may be present in the product gas.

[0045] Various devices, systems, and methods for generating NO, consistent with this disclosure, are described below.

[0046] Figure 1 This is a schematic diagram of a NO system 10 according to some embodiments of the present disclosure. For example... Figure 1 As shown, in some embodiments, system 10 includes a NO generating device 100. The NO generating device 100 generates NO using one or more electrochemical reactions. In some embodiments, system 10 includes a carrier gas source 200 disposed upstream of and in fluid communication with the NO generating device 100. The carrier gas source 200 can generate or supply a carrier gas 122. The carrier gas 122 can be supplied to the NO generating device 100 to transport the generated NO out of the NO generating device 100. For example, the carrier gas 122 can sweep, purge, and / or entrain the generated NO from the NO generating device 100.

[0047] NO generating device 100 can output NO generated in a product gas. The product gas may include one or more components. In some embodiments, the product gas includes a carrier gas. The product gas can flow from NO generating device 100 to one or more downstream systems or devices. One or more downstream systems or devices can transport, process, and / or store the product gas from NO generating device 100. For example, the product gas may include one or more impurities, such as moisture, one or more toxic gases, and solid substances. In some embodiments, system 10 includes one or more filtration systems or devices to reduce or remove one or more impurities from the product gas. In some embodiments, system 10 includes a ventilation circuit to deliver NO to a patient under aerobic or anaerobic conditions. Various embodiments of system 10 and methods for generating NO using system 10 are described below.

[0048] Electrochemical generation of NO

[0049] Figure 2 This is a schematic diagram of a NO generating apparatus 100 according to some embodiments of the present disclosure. The NO generating apparatus 100 is configured to generate NO from one or more electrochemical reactions in a reaction medium 112. Figure 2 As shown, in some embodiments, the NO generating apparatus 100 includes a reaction chamber 102 and a plurality of electrodes. In some embodiments, the reaction chamber 102 includes a liquid region 108 and a gas region 110. The liquid region 108 is configured to receive a reaction medium 112. The gas region 110 is configured to receive gases generated in and / or transported from the reaction medium 112.

[0050] In some embodiments, the reaction chamber 102 has a first side 104 and a second side 106. The first side 104 may be the top side of the reaction chamber 102. The second side 106 may be the bottom side of the reaction chamber 102. The first side 104 and the second side 106 may extend parallel to each other. For example, the first side 104 may have a surface extending parallel to the surface of the second side 106. A liquid region 108 may be disposed adjacent to the second side 106. A gas region 110 may be disposed adjacent to the first side 104.

[0051] like Figure 2As shown, in some embodiments, the NO generating apparatus 100 includes an inlet circuit 120 and an outlet circuit 124. The inlet circuit 120 is located downstream of and in fluid communication with the carrier gas source 200. In some embodiments, the inlet circuit 120 has at least one outlet 144, such as an opening, in the liquid region 108. The inlet circuit 120 can receive and transport the carrier gas 122 to the liquid region 108. The outlet circuit 124 is located downstream of and in fluid communication with the gas region 110 of the reaction chamber 102. In some embodiments, the outlet circuit 124 has at least one inlet, such as an opening, in the gas region 110. For example, the carrier gas 122 can transport the generated NO from the gas region 110 out of the NO generating apparatus 100 through the outlet circuit 124.

[0052] In some embodiments, the NO generating apparatus 100 may include one or more NO sensors (not shown) configured to detect the concentration of NO in the product gas. The NO sensors can be positioned in any suitable location. For example, the NO sensors may be positioned in contact with the product gas in the gas region 110. In some embodiments, the NO sensors are located in or near the outlet circuit 124 of the reaction chamber 102. For example, the NO sensors may be located at the opening of the outlet circuit 124, such as at the inlet or outlet of the outlet circuit 124. For example, the NO sensors may be located within the conduit of the outlet circuit 124. In some embodiments, the NO sensors may be located downstream of the outlet circuit 124 or downstream of one or more filters or filtration devices downstream of the outlet circuit 124. For example, as... Figure 1 and 2 As shown, the NO sensor 125 can be located downstream of the filter 506 of the filtration system 500, which is located downstream of the outlet circuit 124.

[0053] In some embodiments, the NO generating apparatus 100 includes a plurality of electrodes comprising a first electrode 116 and a second electrode 118. The first electrode 116 and the second electrode 118 are disposed in a reaction medium 112. In some embodiments, the second electrode 118 is the counter electrode of the first electrode 116. For example, the first electrode 116 may be a cathode, and the second electrode 118 may be an anode, or vice versa. As described herein, while some embodiments of the present disclosure are described with respect to the first electrode 116, similar embodiments with respect to the second electrode 118 will be apparent to those skilled in the art. In some embodiments, the plurality of electrodes includes a reference electrode. The reference electrode may be the first electrode 116, the second electrode 118, or a third electrode (not shown). The reference electrode may be disposed within or outside the reaction medium 112.

[0054] In some embodiments, such as Figure 2 As shown, the first electrode 116 and the second electrode 118 are electrically connected to an energy source 114. In some embodiments, the energy source 114 is configured to apply a voltage to the first electrode 116 or generate a potential difference between the first electrode 116 and the second electrode 118. In some embodiments, the energy source 114 is configured to apply a current to the first electrode 116 or generate a current flowing from the second electrode 118 to the first electrode 116, and vice versa. The voltage or current applied to the electrodes can be predetermined and / or adjusted based on one or more conditions, such as the desired concentration and / or flow rate of NO in the product gas.

[0055] In some embodiments, the voltage applied to the first electrode 116 can be measured as the potential difference between the first electrode 116 and the second electrode 118, or between the second electrode 118 and the first electrode 116. In some embodiments, the current applied to the first electrode 116 can be measured as the current flowing through the first electrode 116. In some embodiments, the voltage applied to the first electrode 116 can be measured as the potential difference between the first electrode 116 and the reference electrode, or between the reference electrode and the first electrode 116.

[0056] In some embodiments, the reaction medium 112 is a liquid. For example, the reaction medium 112 may include an aqueous solution or an organic solution. In some embodiments, the reaction medium 112 includes a nitrite ion source. In some embodiments, the NO generating device 100 generates NO by electrochemically reducing nitrite ions in the reaction medium 112 to NO adjacent to and / or located on the surface of an electrode (e.g., the first electrode 116). In some embodiments, the electrochemical reduction of nitrite ions to NO is facilitated or achieved by one or more catalysts. In some embodiments, one or more catalysts are dissolved or dispersed in the reaction medium 112. One or more catalysts may be adjacent to and / or in contact with the surface of the electrode (e.g., the first electrode 116) to act individually or collectively as electron transfer mediators between the electrode surface and nitrite ions in the reaction medium 112.

[0057] In some embodiments, the catalyst may be immobilized on the surface of an electrode (e.g., the first electrode 116). In some embodiments, the catalyst comprises one or more compounds selected from the group consisting of cystine, cysteine, methionine, thiophene, and their derivatives. For example, one or more catalysts may be covalently attached, adsorbed, doped, or covalently attached to a material deposited on the electrode, such as a polymer, thin film, or hydrogel. Some examples of materials that can be deposited on an electrode can be found in PCT / US2018 / 027081. As described herein, PCT / US2018 / 027081 is incorporated herein by reference for its application to the relevant topics discussed in this disclosure.

[0058] A catalyst can facilitate the electrochemical reduction of nitrite ions in the reaction medium 112 to NO at and / or near the surface of an electrode (e.g., the first electrode 116). In some embodiments, the catalyst comprises a metal-containing compound, such as a metal-ligand complex. In some embodiments, the metal-containing compound can facilitate the electrochemical reduction of nitrite ions in the reaction medium 112 to NO according to the following reaction:

[0059] M(first price)(l)+e - →M (second valence) (l) Reaction 1

[0060] M(secondary valence)(l)+NO2 - +2H + →M(primary valence)(l) + NO + H₂O Reaction 2

[0061] Where M(l) represents a metal-ligand complex, M represents at least one metal ion, l represents at least one surrounding ligand or complexing agent, and NO2 - This represents the nitrite ion. NO can be generated by reducing at least one metal ion in a metal-ligand complex from its primary valence to its secondary valence, where the secondary valence is lower than the primary valence. The reduced metal-ligand complex acts as an intermediate in reducing nitrite ions in reaction medium 112 to NO while simultaneously being oxidized back to the original metal-ligand complex.

[0062] At least one metal ion may include, for example, one or more metal ions selected from copper, iron, titanium, chromium, manganese, cobalt, and nickel ions. At least one surrounding ligand or complexing agent may include, for example, one or more selected from tris(2-pyridylmethyl)amine (TPA or TPMA), 1,4,7-triazacyclononane, 1,4,7-trimethyl-1,4,7-triazacyclononane (Me3TACN), tris(2-aminoethyl)amine, 3-((2-aminoethyl)amino)propionic acid, and bis(2-aminopyridinyl)propionic acid. Some other examples of metal ions or surrounding ligands or complexing agents can be found in PCT / US2018 / 027081.

[0063] In some embodiments, using a metal-ligand complex as a catalyst allows for the generation and / or regulation of NO using a cathode voltage or cathode current. In some embodiments, controlling the magnitude of the voltage or current applied to an electrode (e.g., the first electrode 116) allows for control of the ratio of the reduced form of the metal-ligand complex to its oxidized form, for example, at and / or near the electrode surface. This can allow for control of the amount and / or rate of NO generated in the reaction medium 112 at a given concentration of nitrite ions and the metal-ligand complex.

[0064] In some embodiments, the electrode (e.g., the first electrode 116) may have any suitable shape including one or more surfaces. For example, the first electrode 116 may include a plate, sheet, or mesh. In some embodiments, NO is electrochemically generated from one or more electrochemical reactions occurring at and / or near one or more surfaces of the first electrode 116 when a cathode voltage is applied to the first electrode 116, or when a cathode current is applied to the first electrode 116. Some or all of the NO generated from the electrochemical reactions at and / or near the surface of the first electrode 116 in the reaction medium 112 may be transported out of the reaction medium 112 and transported to the gas region 110 of the reaction chamber 102. For example, the carrier gas 122 may be used to sweep, purge, and / or entrain some or all of the NO generated from the reaction medium 112.

[0065] Energy source 114 may include one or more suitable power devices or circuits that allow voltage or current to be applied to the electrodes, such as electrical outlets, power circuits, DC power supplies, AC power supplies, generators, or energy storage devices. Energy storage devices may include, for example, one or more batteries or fuel cells. In some embodiments, energy source 114 includes one or more electrical circuits for controlling or regulating the voltage or current applied to the electrodes. In some embodiments, one or more electrical circuits may include voltage regulators to control or regulate the voltage applied to the electrodes. In some embodiments, one or more electrical circuits may include constant current devices to control or regulate the current flowing through the electrodes.

[0066] In some embodiments, the polarity of the first electrode 116 and the second electrode 118 can be switched. For example, the polarity of the first electrode 116 and the second electrode 118 can be switched by reversing the polarity of the energy source 114, such as by reversing the polarity of the voltage or current from the DC power supply using a reversing switch circuit, or by using an AC power supply. For example, the energy source 114 is an AC power supply configured to apply a periodic alternating current or alternating voltage to the electrodes.

[0067] For example, the switching of electrode polarity can be automatically controlled by a control loop according to a software program. Alternatively or additionally, the switching of electrode polarity can be manually controlled by the user, for example, by using a switch. The polarity of the electrode can be switched during NO generation, between two operating cycles, or between two stages. NO in the reaction medium 112 in contact with or adjacent to the electrode may cause electrode degradation and may negatively affect NO generation efficiency. Switching the electrode polarity can increase the effective surface area for NO generation and can increase the lifespan of the electrode and / or the NO generation device 100.

[0068] The electrodes of the NO generating device 100 (e.g., the first electrode 116, the second electrode 118, or the reference electrode) may be made of one or more materials. One or more electrodes of the NO generating device 100 may be made of the same material or different materials. In some embodiments, the electrodes of the NO generating device 100 include at least one conductive material. This at least one conductive material may be metallic or non-metallic. This at least one conductive material may be selected from, for example, a group of conductive materials including platinum, palladium, gold, copper, brass, silver, carbon, glassy carbon, boron-doped diamond (BDD), graphite, stainless steel, titanium, iridium, ruthenium, and one or more alloys thereof, such as ruthenium-iridium alloys.

[0069] In some embodiments, the electrodes of the NO generating device 100 include at least one substrate. The at least one substrate can be a metallic or non-metallic material. The at least one substrate can be selected from, for example, a group of materials including silicon dioxide, conductive glass, tin-doped indium oxide, fluorine-doped indium oxide, conductive plastics, platinum, gold, copper, brass, silver, carbon, glassy carbon, boron-doped diamond (BDD), graphite, stainless steel, titanium, iridium, ruthenium, and one or more alloys thereof, such as ruthenium-iridium alloys. In some embodiments, the electrodes of the NO generating device 100 include at least one conductive material coated on at least one substrate. Any suitable plating method, such as electroplating, physical vapor deposition (PVD), chemical vapor deposition (CVD), or plasma-enhanced chemical vapor deposition (PECVD), can be used to coat at least one conductive material onto at least one substrate.

[0070] The electrodes of the NO generating device 100 (such as the first electrode 116) can have any shape, structure, and / or size. In some embodiments, the first electrode 116 provides a surface on which NO is electrochemically generated, both thereon and / or in its vicinity. For example, the first electrode 116 can be in the form of a plate, sheet, mesh, or rod. The surface of the first electrode 116 can have a surface area. This surface area may be positively correlated with the rate of NO generation at the surface. The first electrode 116 can have a structure that allows for a larger surface area, such as a porous structure.

[0071] Figure 3A This is a schematic diagram of a first electrode 116 and a second electrode 118 of a NO generating apparatus 100 according to some embodiments of the present disclosure. The first electrode 116 and the second electrode 118 can be placed in the reaction chamber 102 using suitable means, such that the surfaces of the first electrode and the second electrode are disposed in the reaction medium 112. For example, as... Figure 3AAs shown, frame 126 can be used to place the first electrode 116 and the second electrode 118 in reaction chamber 102. Frame 126 may have a top side that is connected to a first side 104 of reaction chamber 102. The first electrode 116 and the second electrode 118 can be attached to frame 126 in any suitable manner, such as by using screws, clips, wires, clamps, or any other suitable fastening means.

[0072] In some embodiments, such as Figure 3A As shown, the first electrode 116 and the second electrode 118 comprise two rectangular plates having one or more surfaces 128. The first electrode 116 and the second electrode 118 may have the same size or similar sizes. In some embodiments, the first electrode 116 and / or the second electrode 118 have a length from approximately 3 cm to approximately 15 cm. In some embodiments, the first electrode 116 and / or the second electrode 118 have a width from approximately 2 cm to approximately 10 cm. The first electrode 116 and the second electrode 118 may be spaced apart at any suitable distance, such as from approximately 0.2 cm to approximately 10 cm apart. The first electrode 116 and the second electrode 118 may be configured such that at least a portion of the surface 128 of the first electrode 116 extends along at least a portion of the surface 128 of the second electrode 118, such as extending parallel to at least a portion of the surface of the second electrode.

[0073] In some embodiments, such as Figure 1-2 As shown, the first electrode 116 and the second electrode 118 are vertically positioned. For example, the first electrode 116 and the second electrode may be arranged perpendicular to the second side 106 of the reaction chamber 102. In some embodiments, each electrode includes a top edge 130 and a bottom edge 132. The top edge 130 may extend along the first side 104 of the reaction chamber 102, for example, parallel to the first side of the reaction chamber. The bottom edge 132 may extend along the second side of the reaction chamber 102, for example, parallel to the second side of the reaction chamber.

[0074] Wires can be used to electrically connect the electrodes to the power source 114. For example, as... Figure 3A As shown, wire 136 is connected at one end to an energy source 114 (not shown) and at the second end to an electrode, such as a first electrode 116 or a second electrode 118. Wire 136 may be soldered or brazed to the electrode (e.g., the first electrode 116 and the second electrode 118). Wire 136 may be made of one or more conductive materials (e.g., copper, aluminum, steel, or silver) and may be treated for corrosion protection. In some embodiments, wire 136 is fastened to frame 126.

[0075] In some embodiments, the voltage applied to the electrode (e.g., the first electrode 116) is a DC voltage. In some embodiments, the voltage applied to the electrode (e.g., the first electrode 116) ranges from about 1.0V to about 5.0V, such as from about 1.0V to about 2.0V, from about 2.0V to about 3.0V, from about 3.0V to about 4.0V, from about 4.0V to about 5.0V, or a combination thereof.

[0076] In some embodiments, the energy source 114 is configured to apply an excitation voltage to an electrode (e.g., the first electrode 116). In some embodiments, the excitation voltage is approximately 2 to approximately 8 times a predetermined voltage, such as approximately 2, approximately 3, approximately 4, approximately 5, approximately 6, approximately 7, or approximately 8 times.

[0077] In some embodiments, the current applied to the electrode (e.g., the first electrode 116) is a DC current. In some embodiments, the current applied to the electrode (e.g., the first electrode 116) ranges from about 0 mA to about 600 mA, such as from about 0 mA to about 10 mA, from about 10 mA to about 50 mA, from about 50 mA to about 100 mA, from about 100 mA to about 200 mA, from about 200 mA to about 300 mA, from about 300 mA to about 400 mA, from about 400 mA to about 500 mA, from about 500 mA to about 600 mA, or combinations thereof.

[0078] In some embodiments, the energy source 114 is configured to apply an excitation current to the first electrode 116. In some embodiments, the excitation current is approximately 2 to approximately 8 times a predetermined current, for example, approximately 2, approximately 3, approximately 4, approximately 5, approximately 6, approximately 7, or approximately 8 times.

[0079] Those skilled in the art will recognize that the excitation voltage or excitation current need not be an integer multiple of a predetermined voltage or predetermined current. Any value within this range can satisfy the purposes disclosed in this disclosure.

[0080] The polarity of the voltage or current can be switched manually or by software and / or hardware control, thereby exchanging the polarity of the first electrode 116 and the second electrode 118. In some embodiments, the polarity of the first electrode 116 and the second electrode 118 is switched periodically. For example, the polarity of the first electrode 116 and the second electrode 118 may be switched approximately every 10 minutes to approximately every 10 hours, such as approximately every 5 minutes to approximately every 10 minutes, approximately every 10 minutes to approximately every 30 minutes, approximately every 30 minutes to approximately every 1 hour, approximately every 1 hour to approximately every 2 hours, approximately every 2 hours to approximately every 3 hours, approximately every 3 hours to approximately every 4 hours, approximately every 4 hours to approximately every 5 hours, approximately every 5 hours to approximately every 6 hours, approximately every 6 hours to approximately every 7 hours, approximately every 7 hours to approximately every 8 hours, approximately every 8 hours to approximately every 9 hours, approximately every 9 hours to approximately every 10 hours, or combinations thereof.

[0081] In some embodiments, reaction medium 112 includes at least one buffer or buffering component to regulate or prevent changes in the pH of reaction medium 112. For example, the at least one buffer or buffering component may include one or more organic or inorganic buffers or buffering components selected from the group consisting of sodium hydroxide (NaOH), 4-(2-hydroxyethyl)-1-piperazine ethanesulfonic acid (HEPES), 3-(N-morpholino)propanesulfonic acid (MOPS), citric acid, sodium citrate, tris(hydroxymethyl)aminomethane (Tris), phosphate-buffered saline (PBS), boric acid, borax, and borate-borax buffers. Some other examples of buffers or buffering components that may be used in reaction medium 112 can be found in PCT / US2018 / 027081.

[0082] At least one buffer or buffer component in reaction medium 112 may have any suitable concentration. For example, the concentration range of at least one buffer or buffer component in reaction medium 112 may be from about 0.01 mol / L to about 0.5 mol / L, from about 0.5 mol / L to about 1.0 mol / L, from about 1.0 mol / L to about 1.5 mol / L, from about 1.5 mol / L to about 2.0 mol / L, from about 2.0 mol / L to about 2.5 mol / L, from about 2.5 mol / L to about 3.0 mol / L, or combinations thereof.

[0083] The nitrite ion source in reaction medium 112 may include one or more nitrites. The nitrite may be an organic or inorganic nitrite. Examples of organic nitrites include organic ammonium nitrites, such as tetramethylammonium nitrite and tetraethylammonium nitrite. Examples of inorganic nitrites include metal nitrites, such as nitrites of lithium, sodium, potassium, rubidium, calcium, magnesium, aluminum, and iron. Some other examples of nitrite ion sources can be found in PCT / US2018 / 027081. The concentration range of one or more nitrites in reaction medium 112 can be from about 0.01 mol / L to about 0.5 mol / L, from about 0.5 mol / L to about 1.0 mol / L, from about 1.0 mol / L to about 1.5 mol / L, from about 1.5 mol / L to about 2.0 mol / L, from about 2.0 mol / L to about 2.5 mol / L, from about 2.5 mol / L to about 3.0 mol / L, from about 3.0 mol / L to about 3.5 mol / L, from about 3.5 mol / L to about 4.0 mol / L, from about 4.5 mol / L to about 5.0 mol / L, or combinations thereof.

[0084] When the catalyst is dissolved in reaction medium 112, the concentration of the catalyst in reaction medium 112 can range from about 1 mmol / L to about 5 mmol / L, from about 1 mmol / L to about 10 mmol / L, from about 1 mmol / L to about 15 mmol / L, from about 5 mmol / L to about 10 mmol / L, from about 5 mmol / L to about 15 mmol / L, or from about 10 mmol / L to about 15 mmol / L.

[0085] The reaction medium 112 may include one or more other components. For example, the reaction medium 112 may include one or more additives, such as ethylenediaminetetraacetic acid (EDTA), which can promote one or more electrochemical reactions for the generation of NO.

[0086] Embodiments of the NO generating apparatus 100 may include one or more of the following features to improve the performance of the NO generating apparatus 100, such as increasing the reaction rate and / or Faraday efficiency of the NO generating apparatus 100, increasing the concentration of NO in the product gas, or increasing the amount or concentration of NO generated using a given amount of reaction medium 112. For example, the Faraday efficiency of the NO generating apparatus 100 may be in the range of about 70% to about 80% or higher.

[0087] Temperature control of the reaction medium

[0088] In some embodiments, the reaction medium 112 is maintained at or near the reaction temperature or within a temperature range. The electrochemical reaction in the reaction chamber 102 can have the highest, desired, or optimized reaction rate and / or Faraday efficiency at or near the reaction temperature or within a temperature range. The reaction temperature or temperature range can be determined based on one or more conditions, such as the composition of the buffer and / or catalyst and the concentration in the reaction medium 112. In some embodiments, the range of the reaction temperature or temperature range can be from about 5°C to about 10°C, from about 10°C to about 15°C, from about 15°C to about 20°C, from about 20°C to about 25°C, from about 25°C to about 30°C, from about 20°C to about 30°C, from about 30°C to about 35°C, from about 35°C to about 40°C, from about 40°C to about 45°C, or combinations thereof.

[0089] In some embodiments, the NO generating apparatus 100 includes a temperature maintaining device 138 to control the temperature of the reaction medium 112. For example, such as... Figure 1-2 As shown, the temperature holding device 138 can be located near the reaction chamber 102, such as below, beside, or around the reaction chamber 102. In some embodiments, the temperature holding device 138 includes one or more temperature control devices, such as a temperature-controlled water bath, a temperature-controlled oil bath, an air agitator (e.g., a fan), a heat radiator, a thermoelectric heating and / or cooling device (e.g., a pn junction device).

[0090] In some embodiments, the NO generating apparatus 100 includes a temperature sensor 140 disposed in the reaction medium 112 and in communication with a temperature holding device 138. The temperature holding device 138 can monitor the temperature of the reaction medium 112 based on a signal from the temperature sensor 140. The temperature holding device 138 can heat or cool the reaction medium 112 in response to the signal. In some embodiments, the voltage or current applied to an electrode (e.g., the first electrode 116) can be adjusted by an energy source 114 based on a signal from the temperature sensor 140. For example, the control loop of the energy source 114 can communicate with the temperature sensor 140 and can adjust the amplitude and / or polarity of the voltage or current applied to the first electrode 116.

[0091] Transporting NO from the reaction medium

[0092] Some or all of the NO generated in the reaction medium 112 can be transported from the reaction medium 112. For example, the NO generated in the reaction medium 112 can be transported, for instance, by sweeping, purging, and / or entraining it from the reaction medium 112 into the gas region 110 using a carrier gas 122.

[0093] In some embodiments, such as Figure 2 As shown, the carrier gas 122 is used to sweep the surface 128 of an electrode (e.g., the first electrode 116). Sweeping the electrode surface can increase the Faraday efficiency and / or reaction rate of the electrochemical reaction at and / or near the electrode surface and / or increase the NO concentration of the product gas. For example, in some cases, one or more metal ions of the catalyst in the reaction medium 112, such as the M (monovalent) ions generated by electrochemical reaction 2, may precipitate in an insoluble form. For example, the metal ion of the catalyst may be Cu. 2+ In some cases, Cu 2+ Precipitation can occur from the following reactions:

[0094] Cu 2+ +2OH - →Cu(OH)₂↓→CuO+H₂O

[0095] Precipitation of metal ions from the catalyst in reaction medium 112 can reduce the catalyst concentration in reaction medium 112 and decrease the rate of the electrochemical reaction for NO generation. Precipitation of metal ions can lead to the deposition of insoluble forms of the metal ions, such as Cu(OH)₂, on the electrode surface. This can reduce the surface area available for NO generation and also reduce the electrode lifetime. Sweeping the electrode surface can increase the movement of substances (such as metal ions) at and / or near the electrode surface. This can reduce or inhibit the deposition of metal ions on the surface, thus increasing the NO generation rate and / or the NO concentration in the product gas.

[0096] The carrier gas 122 can be introduced into the reaction medium 112 through one or more flow control devices. For example, such as... Figure 2 As shown, the carrier gas source 200 may include a flow control device 204 that measures and controls the mass or volumetric flow rate of the carrier gas stream 122 introduced into the reaction medium 112. A valve 206 may be located downstream of the flow control device 204 to protect it. For example, the valve 206 may be a one-way valve configured to prevent the reaction medium 112 from flowing back from the inlet circuit 120 to the flow control device 204. An embodiment of supplying carrier gas 122 from the carrier gas source 200 to the NO generating apparatus 100 will be further described below.

[0097] In some embodiments, a carrier gas 122 is introduced into the reaction medium 112 in the form of bubbles configured to propagate along a bubble path. The bubble path may extend along the surface of an electrode (e.g., surface 128 of the first electrode 116) to sweep across that surface. As the carrier gas bubbles rise to the surface of the reaction medium 112, they may entrain, sweep, and / or purge NO generated near and / or at the surface of the first electrode 116. The carrier gas bubbles may mix or disturb the reaction medium 112 near the surface 128 of the first electrode 116, and may increase the movement of substances (e.g., metal ions) near that surface. The carrier gas bubbles may purge NO dissolved in the reaction medium 112 from the reaction medium 112 into the gas region 110.

[0098] In some embodiments, the NO generating apparatus 100 includes one or more sprayers to generate bubbles from the carrier gas 122. As used herein, the sprayers may include means or systems configured to emit gas bubbles into a liquid. In some cases, the sprayer may be referred to as a bubbler. One or more sprayers may be positioned at any suitable location in the reaction medium 112 to emit bubbles of the carrier gas 122, thereby transporting (e.g., sweeping, purging, and / or entraining) NO out of the reaction medium 112. For example, one or more sprayers may be positioned above or near the second side 106 of the reaction chamber 102.

[0099] In some embodiments, such as Figure 2 As shown, the NO generating device 100 includes a first sprayer 134 disposed in the reaction medium 112 adjacent to the first electrode 116. In some embodiments, such as Figure 2 As shown, the NO generating device 100 includes a second sprayer 134 disposed adjacent to the second electrode 118. In some embodiments, the sprayer 134 is configured to receive carrier gas 122 and to emit bubbles of carrier gas to sweep across one or more surfaces 128 of the first electrode 116 or the second electrode 118. Figure 3B This is a perspective view of a sprayer 134 according to some embodiments of the present disclosure. Figure 3B As shown, the sprayer 134 can have an elongated shape, such as an elongated cylindrical shape.

[0100] In some embodiments, such as Figure 3A As shown, the sprayer 134 can be positioned along the first electrode 116 or the second electrode 118, such that bubbles emitted from the sprayer 134 can rise and propagate along one or more surfaces 128 of the first electrode 116 or the second electrode 118. For example, as Figure 2 and 3AAs shown, a sprayer 134 may be disposed between the bottom edge 132 of the first electrode 116 or the second electrode 118 and the second side 106 of the reaction chamber 102. Bubbles emitted from the sprayer 134 may propagate along a bubble path extending from the bottom edge 132 through the surface 128 to the top edge 130 of the first electrode 116 or the second electrode 118. In some embodiments, the sprayer 134 may extend along the length of the bottom edge 132 such that bubbles can sweep across the entire surface 128 of the first electrode 116.

[0101] In some embodiments, the distance between the sprayer 134 and the first electrode 116 or the second electrode 118 can be selected to increase the coverage and / or efficiency of sweeping one or more surfaces of the electrodes. The sprayer 134 can be positioned at a distance from the electrode, for example, a distance less than about 1 cm, less than about 5 mm, less than about 2 mm, less than about 1 mm, or less than about 0.5 mm.

[0102] The sprayer 134 can have any suitable structure to receive gas and emit gas bubbles. In some embodiments, the sprayer 134 includes a porous structure 141 that provides a plurality of pores for emitting bubbles. For example, as Figure 3B As shown, the sprayer 134 may include an inner cavity 142 surrounded by a porous structure 141. Gas can flow through the inner cavity 142 and bubble through the pores in the porous structure 141. The inner cavity 142 may have a tubular shape extending from a first opening to a second opening. The inner cavity 142 may extend along the centerline of the sprayer 134 or may not extend along the centerline of the sprayer. The inner cavity 142 may have a diameter selected based on one or more conditions, such as the flow rate of the received gas and the desired density and / or size of the bubbles. For example, the diameter of the inner cavity 142 may range from about 1 mm to about 9 mm, such as from about 1 mm to about 2 mm, from about 2 mm to about 3 mm, from about 3 mm to about 4 mm, from about 4 mm to about 5 mm, from about 5 mm to about 6 mm, from about 6 mm to about 7 mm, from about 7 mm to about 8 mm, from about 8 mm to about 9 mm, or combinations thereof.

[0103] In some embodiments, such as Figure 2 and 3A As shown, the outlet 144 of the inlet circuit 120 is fluidly connected to the sprayer 134 (e.g., the inner cavity 142 of the sprayer 134). Carrier gas 122 can flow from the carrier gas source 200 through the inlet circuit 120 and via the outlet 144 to the sprayer 134. In some embodiments, the sprayer 134 is attached to a sprayer holder 148. In some embodiments, the sprayer holder 148 is attached to a frame 126. The sprayer holder 148 allows the sprayer 134 to be positioned at a desired location.

[0104] In some embodiments, the sprayer holder 148 may include one or more structures for guiding the flow of air bubbles. For example, the sprayer holder 148 may include a housing having one or more openings configured to guide air bubbles emitted from the sprayer 134 to one or more surfaces 128 of the electrode. For example, as Figure 3A As shown, the sprayer holder 148 may include openings located at the top and / or upper portion of the sprayer 134, allowing bubbles to be emitted from the upper portion of the sprayer 134 and propagate along the surface 128 of the first electrode 116. The sprayer holder 148 may include one or more blocking or sealing devices to prevent one or more portions of the sprayer 134 from emitting gas or bubbles. For example, the sprayer holder 148 may have a portion configured to prevent gas from flowing directly out of the inner cavity 142 without passing through the porous structure 141. For example, the sprayer holder 148 may have a portion that blocks or seals a first end of the inner cavity 142 opposite to a second end connected to the outlet 144.

[0105] In some embodiments, the sprayer 134 includes at least one porous material providing a porous structure 141. The density and / or size of the bubbles may depend on one or more conditions, such as gas pressure, gas flow rate, and the pore density and / or size of the at least one porous material. At a given gas flow rate, smaller pores may allow the sprayer 134 to generate smaller bubbles with a higher density. The at least one porous material may include a metallic material, such as stainless steel. The at least one porous material may include a non-metallic material. The non-metallic material may be a polymeric material, such as polyethylene (PE), polycarbonate (PC), polyvinylidene fluoride (PVDF), ceramic, quartz, or silicon carbide.

[0106] The pore size of at least one porous material in the sprayer 134 can be selected based on the desired bubble density, size, and / or flow rate. For example, the pore size range can be from about 0.1 μm to about 0.5 μm, from about 0.1 μm to about 0.2 μm, from about 0.2 μm to about 0.5 μm, from about 0.5 μm to about 1 μm, from about 1.0 μm to about 10 μm, from about 10 μm to about 20 μm, from about 20 μm to about 50 μm, from about 50 μm to about 100 μm, from about 100 μm to about 150 μm. From approximately 150 μm to approximately 200 μm, from approximately 200 μm to approximately 300 μm, from approximately 300 μm to approximately 400 μm, from approximately 400 μm to approximately 500 μm, from approximately 500 μm to approximately 600 μm, from approximately 600 μm to approximately 700 μm, from approximately 700 μm to approximately 800 μm, from approximately 800 μm to approximately 900 μm, from approximately 900 μm to approximately 1 mm, or combinations thereof.

[0107] The porous material of the sprayer 134 can have a certain thickness through which a gas flow can pass to generate bubbles. The thickness of the porous material can be measured from the inner surface to the outer surface of the porous material. Increasing the thickness of the porous material can increase gas flow resistance and reduce foaming efficiency. Decreasing the thickness of the porous material can reduce the density and / or velocity of the bubbles. The thickness of the porous material can be selected to obtain bubbles of any suitable density and / or size for sweeping the electrode surface. For example, the thickness of the porous material can range from about 0.5 mm to about 1 mm, from about 1 mm to about 2 mm, from about 2 mm to about 3 mm, from about 3 mm to about 4 mm, from about 4 mm to about 5 mm, from about 5 mm to about 6 mm, from about 6 mm to about 7 mm, from about 7 mm to about 8 mm, from about 8 mm to about 9 mm, from about 9 mm to about 10 mm, or combinations thereof.

[0108] carrier gas generation

[0109] In some embodiments, carrier gas 122 is generated or supplied by carrier gas source 200. Carrier gas 122 may include any suitable gas, such as air, nitrogen, helium, argon, and oxygen. In some embodiments, carrier gas 122 includes nitrogen. In some embodiments, the concentration of nitrogen in carrier gas 122 is approximately 99.0% or greater by volume. For example, the concentration of nitrogen in carrier gas 122 may be approximately or greater than 99.10%, 99.20%, 99.30%, 99.40%, 99.50%, 99.60%, 99.70%, 99.80%, 99.90%, 99.95%, 99.98%, or 99.99% by volume. Carrier gas 122 may contain oxygen. For example, the concentration of oxygen in carrier gas 122 may be less than approximately 1%, 0.5%, or 0.1%.

[0110] In some embodiments, such as Figure 1 As shown, the carrier gas source 200 includes a nitrogen generating device 202 configured to generate carrier gas 122 from compressed air. In some embodiments, compressed air is supplied to the carrier gas source 200 from an air compressor system or storage tank. In some embodiments, the compressed air is filtered before being supplied to the carrier gas source 200. For example, the carrier gas source 200 may include a filtration device disposed upstream of and configured in fluid communication with the nitrogen generating device 202. The filtration device may include one or more filters, such as dust filters and moisture filters. In some embodiments, the carrier gas source 200 includes a pressure sensor and a pressure controller, such as a pressure regulator or pressure control valve. The pressure controller may regulate the pressure and / or flow rate of the compressed air entering the nitrogen generating device 202 based on a response or signal from the pressure sensor.

[0111] Nitrogen generating device 202 may include one or more suitable means for generating nitrogen from compressed air. In some embodiments, nitrogen generating device 202 includes at least one carbon molecular sieve (CMS). The carbon molecular sieve may have a pore size distribution that allows nitrogen to be separated from the air. In some embodiments, nitrogen generating device 202 includes at least one nitrogen separation membrane. The nitrogen separation membrane may separate nitrogen from the air based on the permeation rates of nitrogen and oxygen through the membrane wall. The nitrogen separation membrane may have any suitable configuration. In some embodiments, the nitrogen separation membrane includes at least one bundle of selectively permeable hollow fibers.

[0112] The nitrogen separation membrane may comprise one or more materials selected from the group consisting of poly(4-methyl-1-pentene), brominated polycarbonate, polypropylene, polyimide, and polydimethylsiloxane. In some embodiments, the nitrogen separation membrane has a plurality of pores with an average pore size ranging from about 0.005 μm to about 0.007 μm, from about 0.007 μm to about 0.01 μm, from about 0.01 μm to about 0.013 μm, from about 0.013 μm to about 0.015 μm, from about 0.015 μm to about 0.017 μm, from about 0.017 μm to about 0.019 μm, from about 0.019 μm to about 0.02 μm, or combinations thereof.

[0113] As described herein, the description of nitrogen generating apparatus 202 is generally applicable to apparatuses that generate other carrier gases (such as helium, argon, and oxygen) and is obvious to those skilled in the art.

[0114] In some embodiments, the nitrogen generating device 202 is located upstream of and in fluid communication with the inlet circuit 120. In some embodiments, such as... Figure 1 As shown, the carrier gas source 200 further includes a flow control device 204 disposed downstream of the nitrogen generating device 202 and upstream of the inlet circuit 120. The flow control device 204 can be configured to control the flow rate of the carrier gas 122 entering the NO generating device 100. Increasing the flow rate of the carrier gas 122 can increase the NO generation rate and / or the concentration of NO in the product gas. For example, increasing the flow rate of the carrier gas 122 can increase the sweeping of the surface of the first electrode 116 and can increase the rate at which the generated NO is transported from the reaction medium 112. In some embodiments, the flow rate of the product gas from the NO generating device 100 output from the outlet circuit 124 is proportional to the flow rate of the carrier gas 122.

[0115] Product gas recirculation relative to the reaction chamber

[0116] In some embodiments, such as Figure 2 As shown, the NO generating device 100 includes a gas circulation loop 300. In some embodiments, the gas circulation loop 300 includes a circulation inlet 302 and a circulation outlet 304. In some embodiments, the circulation inlet 302 is in fluid communication with the gas region 110 of the reaction chamber 102. For example, the circulation inlet 302 may include an opening disposed on the inner wall of the gas region 110 or on the wall of the gas region. In some embodiments, the circulation outlet 304 is in fluid communication with the liquid region 108 of the reaction chamber 102. For example, the circulation outlet 304 may be in fluid communication with the inlet loop 120. For example, the circulation outlet 304 may include an opening disposed on the inner wall of the liquid region 108 or on the wall of the liquid region.

[0117] In some embodiments, the product gas in gas region 110 is recirculated from recirculation inlet 302 to recirculation outlet 304 relative to reaction chamber 102. For example, the recirculated product gas 303 may flow from recirculation inlet 302 to recirculation outlet 304. In some embodiments, gas recirculation loop 300 includes a gas pump 306 configured to generate the recirculated product gas flow 303. Gas pump 306 may be located downstream of recirculation inlet 302 and upstream of recirculation outlet 304.

[0118] In some embodiments, such as Figure 2 As shown, the gas circulation loop 300 is in fluid communication with the outlet loop 124 of the NO generating device 100. For example, the circulation inlet 302 of the gas circulation loop 300 may be in fluid communication with the outlet loop 124. The gas circulation loop 300 and the outlet loop 124 may have a common inlet, such as the circulation inlet 302. The gas circulation loop 300 and the outlet loop 124 may have a common fluid path. In some embodiments, the gas circulation loop 300 includes a first filter device 508 disposed downstream of the circulation inlet 302. The common fluid path may extend from the common inlet to the first filter device 508.

[0119] In some embodiments, a first filter 508 is disposed upstream of the gas pump 306. The filter 508 can reduce or remove liquid and / or solid substances in the recirculated product gas 303. In some embodiments, the gas recirculation loop 300 includes a second filter 307. The second filter 307 may include a capsule filter or a membrane filter. The second filter 307 can remove one or more impurities (such as liquid and solid substances) from the recirculated product gas 303, thereby protecting the gas pump 306.

[0120] The recirculated product gas 303 can be introduced onto the surface of the electrode to sweep across it. In some embodiments, the recirculation outlet 304 is in fluid communication with the sprayer 134. For example, the recirculation outlet 304 may be in fluid communication with the inner cavity 142 of the sprayer 134. A gas pump 306 may be located downstream of the recirculation inlet 302 and upstream of the sprayer 134, and the recirculated product gas 303 may flow from the recirculation inlet 302 to the inner cavity 142 of the sprayer 134.

[0121] In some embodiments, such as Figure 2As shown, the recirculated product gas 303 is combined with the carrier gas 122 to form a gas flow 146. For example, the gas recirculation loop 300 may include a tee connector 308. The tee connector 308 may be fluidly connected to the recirculation outlet 304 and configured to receive the recirculated product gas 303. The tee connector 308 may be fluidly connected to the carrier gas source 200 and / or the inlet loop 120 and configured to receive the carrier gas 122. The tee connector 308 can combine the received recirculated product gas 303 and the carrier gas 122 into the gas flow 146. The tee connector 308 may include any suitable construction, such as a tee fitting or a tee valve. The gas flow 146 may be supplied to the sprayer 134 to generate bubbles for sweeping across the electrode surface.

[0122] In some embodiments, the gas circulation loop 300 may include a valve 206. Valve 206 may be located upstream of the circulation outlet 304. Valve 206 may be located downstream of the gas pump 306 and downstream of the tee connector 308. Valve 206 may prevent backflow of gas flow 146 and / or backflow of reaction medium 112 from reaction chamber 102 to gas pump 306. Gas flow 146 may flow through valve 206 to circulation outlet 304 and outlet 144 and be supplied to one or more sprayers 134. One or more sprayers 134 may also emit bubbles from gas flow 146 to transport (e.g., sweep, purge, and / or entrain) NO generated in reaction medium 112 to gas region 110. For example, in some embodiments, sprayers 134 emit bubbles from gas flow 146 to sweep across the surface of an electrode (e.g., first electrode 116).

[0123] The product gas in gas region 110 may include carrier gas 122 and generated NO. In some embodiments, recirculating the product gas in gas region 110 allows the carrier gas 122 in the product gas to be recycled to the surface of the electrode. Recirculating the carrier gas can reduce the amount of carrier gas required to support NO generation, for example, for sweeping across the first electrode 116 and / or transporting the generated NO. Recirculating the product gas can allow NO to accumulate in the product gas in gas region 110 of reaction chamber 102, thereby allowing a higher concentration of NO in the product gas in gas region 110. This can allow a higher and / or more stable concentration of NO in the product gas transported from gas region 110 of NO generation apparatus 100.

[0124] Figure 4AThis is a graphical representation of the concentration of NO in the product gas and the current applied to the first electrode 116 according to some embodiments of the present disclosure. In this example, the NO generating apparatus 100 may include a reaction chamber 102 having a gas region and a liquid region, a reaction medium 112 contained in the liquid region, a first electrode 116 and a second electrode 118 disposed in the reaction medium 112, a sprayer 134 for sweeping across the surface of the first electrode 116, a gas circulation loop 300 for recirculating the product gas, and the sprayer 134 for sweeping across the first electrode 116. The electrodes may each be made of stainless steel and may each include a plate with a surface area of ​​approximately 5 cm by approximately 6 cm. The reaction medium 112 may include approximately 1.0 mol / L NaNO2, approximately 7 mmol / L CuSO4, approximately 7 mmol / L Me3TACN, and approximately 0.5 mol / L HEPES buffer solution. The HEPES buffer solution can be titrated using a suitable alkaline solution (such as NaOH solution) to give the reaction medium 112 a pH of approximately 6 to approximately 8, such as approximately 7.2. The sprayer 134 can be a cylinder with a length of approximately 7 cm, an inner diameter of approximately 5 mm, and an outer diameter of approximately 10 mm, and the average orifice size of the sprayer is approximately 20 μm. A carrier gas 122 containing approximately 99.7% N2 by volume can be introduced into the sprayer 134 at a flow rate of approximately 300 mL / min. A gas circulation loop 300 can recirculate the product gas at a flow rate of approximately 3 L / min. Figure 4A As shown, increasing the current applied to the first electrode 116 from approximately 0 mA to approximately 300 mA increases the concentration of NO in the product gas. In this example, fitting the data to a linear regression model shows that for every 1 mA of applied current, the concentration of NO in the product gas can increase by approximately 36.1 ppm, and the NO generating device 100 can achieve a Faraday efficiency of 70.7%. Reducing the sweeping of the first electrode 116 reduces the increase in NO concentration per unit applied current and can decrease the Faraday efficiency.

[0125] Figure 4B This is a graphical representation of the change in NO concentration over time in the product gas generated by the NO generating apparatus 100 according to some embodiments of the present disclosure. In this example, the NO generating apparatus 100 may have the same features as described above. Figure 4AThe reaction conditions are the same as those described in the example, except that after an initial application of approximately 300 mA of current during a ramp cycle of approximately 2 minutes, a current of 100 mA can be applied to the first electrode 116 for approximately 60 hours. After the ramp cycle, the concentration of NO in the product gas of the NO generating device 100 increases to approximately 3600 ppm and remains at a steady-state concentration of 3600 ppm or approximately 3600 ppm for approximately 60 hours. Generating this amount of NO typically requires approximately 4 to 5 gas tanks to store approximately 8 L of compressed NO, which has a NO concentration of approximately 800 ppm at a pressure of approximately 13.8 MPa. Using a sprayer 134 to sweep the surface of the first electrode 116 and recirculating the product gas through the gas circulation loop 300 allows for the generation of NO at a stable concentration over a longer period. The amount of NO that can be generated by the NO generating device 100 is, for example, a product gas with a NO concentration of approximately 3600 ppm over approximately 60 hours.

[0126] Separation of NO from the reaction medium

[0127] The reaction medium 112 of the NO generating device 100 can be reused to generate NO before being treated, replaced, or replenished. For example, the reaction medium 112 of the NO generating device 100 can be used to generate NO within multiple operating cycles in one stage or in multiple stages. Some of the generated NO can dissolve in the reaction medium 112 after an operating cycle or a stage. The NO dissolved in the reaction medium 112 can reduce the concentration and / or amount of NO that can be generated by reusing the reaction medium 112 and can increase the waiting time between stages or operating cycles.

[0128] For example, NO dissolved in reaction medium 112 can interact with a metal-ligand complex catalyst, such as Cu(II)-1,4,7-trimethyl-1,4,7-triazacyclononane (Cu(Me3TACN)). For instance, during the waiting time between two stages, NO dissolved in reaction medium 112 can bind to the central copper ion of Cu(Me3TACN). This can reduce the concentration of the metal-ligand complex in reaction medium 112 for catalyzing the electrochemical reaction for NO production in the next stage, and can reduce the reaction rate of the next stage and / or the concentration of NO in the product gas. In some cases, the concentration of NO in the product gas of one stage may be lower than the concentration of NO in the product gas of the previous stage, for example, by about 10% to about 30%.

[0129] In some embodiments, one or more sprayers 134 disposed in the reaction medium 112 may generate gas bubbles to purge dissolved NO from the reaction medium 112 into the gas region 110, thereby reducing the amount of dissolved NO in the reaction medium 112. In some embodiments, sweeping the surface of the electrode may reduce the amount of NO dissolved in the reaction medium 112. For example, the sprayer 134 may generate gas bubbles that propagate along and sweep across the surface 128 of the first electrode 116. The gas bubbles may entrain and / or sweep away NO generated at and / or near the surface of the first electrode 116 from the reaction medium 112, which may reduce or prevent the dissolved NO in the reaction medium 112.

[0130] In some embodiments, such as Figure 1 and Figure 2 As shown, the NO generating apparatus 100 includes a liquid-gas separation circuit 400 to reduce or remove dissolved NO in the reaction medium 112. The liquid-gas separation circuit 400 is configured to circulate a fluid flow (such as a liquid flow or a gas flow) relative to the reaction chamber 102. The liquid-gas separation circuit 400 can be used before, during, and / or after reusing the reaction medium 112 to generate NO.

[0131] In some embodiments, such as Figure 2 As shown, the liquid-gas separation circuit 400 includes a first port 402 and a second port 410. In some embodiments, the first port 402 is in fluid communication with a liquid region 108. The first port 402 may include an opening in the liquid region 108 of the reaction chamber 102 (e.g., below the level of the reaction medium 112). In some embodiments, the second port 410 is in fluid communication with a gas region 110. The second port 410 may have an opening in the gas region 110 of the reaction chamber 102 (e.g., above the level of the reaction medium 112). In some embodiments, the liquid-gas separation circuit 400 is configured to circulate the reaction medium flow 112 relative to the reaction chamber 102 from the first port 402 to the second port 410. In some embodiments, the liquid-gas separation circuit 400 is configured to circulate a product gas flow relative to the reaction chamber 102 from the second port 410 to the first port 402.

[0132] In some embodiments, the liquid-gas separation circuit 400 includes a pump 406. In some embodiments, pump 406 is a liquid-gas dual-purpose pump. In some embodiments, pump 406 is a reversible pump. Pump 406 can generate a fluid flow from a first port 402 to a second port 410 or from a second port 410 to a first port 402. In some embodiments, the fluid flow is a liquid flow. For example, pump 406 can generate a reaction medium flow 112 from the first port 402 to the second port 410. In some embodiments, the fluid flow is a gas flow. For example, pump 406 can generate a product gas flow from the second port 410 to the first port 402.

[0133] Pump 406 can generate a fluid flow at any suitable flow rate. For example, pump 406 can generate a fluid flow (such as a reaction medium flow) at a certain flow rate ranging from about 0.25 L / min to about 10 L / min, such as from about 0.5 L / min to about 1.0 L / min, from about 1.0 L / min to about 1.5 L / min, from about 1.5 L / min to about 2.0 L / min, from about 2.0 L / min to about 2.5 L / min, from about 2.5 L / min to about 3.0 L / min, from about 3.0 L / min to about 3.5 L / min, from about 3.5 L / min to about 4.0 L / min, from about 4.0 L / min to about 4.5 L / min, and from about 4... 0.5L / min to about 5.0L / min, from about 5.0L / min to about 5.5L / min, from about 5.5L / min to about 6.0L / min, from about 6.0L / min to about 6.5L / min, from about 6.5L / min to about 7.0L / min, from about 7.0L / min to about 7.5L / min, from about 7.5L / min to about 8.0L / min, from about 8.0L / min to about 8.5L / min, from about 8.5L / min to about 9L / min, from about 9.0L / min to about 9.5L / min, from about 9.5L / min to about 10L / min, or combinations thereof.

[0134] In some embodiments, such as Figure 1 and Figure 2As shown, the liquid-gas separation circuit 400 includes a liquid-gas separation device 408. In some embodiments, the liquid-gas separation device 408 is disposed between a first port 402 and a second port 410. The liquid-gas separation device 408 may be disposed downstream or upstream of the pump 406. In some embodiments, the liquid-gas separation device 408 includes at least one first chamber 414 and at least one second chamber 416. The first chamber 414 and / or the second chamber 416 may have any suitable shape and size. For example, the first chamber 414 and / or the second chamber 416 may have a tubular structure. The first chamber 414 may be received in the second chamber 416, or vice versa. In some embodiments, the liquid-gas separation device 408 includes a housing or enclosure configured to enclose the first chamber 414 and the second chamber 416.

[0135] In some embodiments, the first chamber 414 and the second chamber 416 are separated by a separation membrane. The separation membrane may comprise an NO-permeable material. For example, the separation membrane may comprise materials such as polydimethylsiloxane (PDMS), silicone resin, or polypropylene. NO can diffuse from the liquid in the first chamber 414 through the separation membrane into the gas in the second chamber 416. The separation membrane can have any suitable configuration. For example, a plurality of hollow fibers having walls formed by the separation membrane.

[0136] The separation membrane can be selected to have any suitable area that allows for the reduction or removal of dissolved NO in the reaction medium 112 within a certain cycle and / or a certain circulation volume. In some embodiments, the separation membrane of the liquid-gas separation device 408 has a surface area ranging from approximately 500 cm². 2 Up to approximately 50,000 cm 2 For example, from about 500cm 2 Up to approximately 1000cm 2 From approximately 1000cm 2 Up to approximately 5000cm 2 From approximately 5000cm 2 Up to approximately 10,000 cm 2 From approximately 10,000 cm 2 Up to approximately 15000cm 2 From approximately 15000cm 2 Up to approximately 20,000 cm 2 From approximately 20,000 cm 2 Up to approximately 25,000 cm 2 From approximately 25,000 cm 2 Up to approximately 30,000 cm 2 From approximately 30,000 cm 2 Up to approximately 35000cm 2From approximately 35,000 cm 2 Up to approximately 40,000 cm 2 From approximately 40,000 cm 2 Up to approximately 45,000 cm 2 From approximately 45,000 cm 2 Up to approximately 50,000 cm 2 , or combinations thereof.

[0137] In some embodiments, the first chamber 414 includes an inlet 418 and an outlet 420. A pump 406 can drive the reaction medium 112 from the inlet 418 through the first chamber 414 to the outlet 420. As the reaction medium 112 flows through the first chamber 414, NO dissolved in the reaction medium 112 can diffuse through a separation membrane into the second chamber 416. In some embodiments, the second chamber 416 includes an inlet 422 and an outlet 426. Sweeped gas can flow from the inlet 422 through the second chamber 416 to the outlet 426. The swept gas can carry the NO diffused into the second chamber 416 as a mixed gas out of the outlet 426. The mixed gas can be transported to an exhaust gas treatment device 700, as further described below.

[0138] The scavenging gas can include any suitable gas, such as air, oxygen, and nitrogen, or combinations thereof. The scavenging gas can be supplied from a gas source (such as carrier gas source 200) to inlet 422. In some embodiments, carrier gas 122 is used as the scavenging gas. For example, a fluid controller 424 can be used to control the flow of carrier gas 122 from carrier gas source 200 to inlet 422. The fluid controller 424 can include a pressure controller, such as a pressure control valve or pressure regulator.

[0139] In some embodiments, such as Figure 2 As shown, the NO generating device 100 includes a filtration device 412. In some embodiments, the filtration device 412 is disposed upstream of the liquid-gas separator 408. The filtration device 412 may include one or more filters configured to filter one or more impurities (e.g., solid substances) from the reaction medium 112. The filtration device 412 can protect the separation membrane of the liquid-gas separator 408 from damage by impurities in the reaction medium 112 as the reaction medium 112 flows through it.

[0140] In some embodiments, the liquid-gas separation circuit 400 has an operating mode and a cleaning mode. In the operating mode, the liquid-gas separation circuit 400 reduces or removes dissolved NO in the reaction medium 112 by circulating the reaction medium 112 from the first port 402 through the liquid-gas separator 408 to the second port 410. In the cleaning mode, the gas in the gas region 110 of the reaction chamber 102 can be circulated from the second port 410 through the liquid-gas separator 408 back to the first port 402. Circulating the gas through the liquid-gas separator 408 allows residual reaction medium 112 in the liquid-gas separator 408 to be transported back to the reaction chamber 102 after the operating mode. For example, pump 406 can generate a fluid flow (such as a gas flow in gas region 110) at a certain flow rate, the certain flow rate ranging from about 0.25 L / min to about 5 L / min, such as from about 0.25 L / min to about 0.5 L / min, from about 0.5 L / min to about 1.0 L / min, from about 1.0 L / min to about 1.5 L / min, from about 1.5 L / min to about 2.0 L / min, from about 2.0 L / min to about 2.5 L / min, from about 2.5 L / min to about 3.0 L / min, from about 3.0 L / min to about 3.5 L / min, from about 3.5 L / min to about 4.0 L / min, from about 4.0 L / min to about 4.5 L / min, from about 4.5 L / min to about 5.0 L / min, or combinations thereof. The cleaning mode can reduce the loss of reaction medium 112 and extend the life of reaction medium 112 and / or NO generation device 100. The cleaning mode can dry the separation membrane and prepare it for the next operating mode.

[0141] In some embodiments, such as Figure 2 As shown, the liquid-gas separation circuit 400 includes a switching valve 404 for switching the liquid-gas separation circuit 400 between an operating mode and a cleaning mode. In some embodiments, the switching valve 404 includes one or more valves configured to control the direction of fluid flow in the liquid-gas separation circuit 400. For example, the switching valve 404 may include a set of normally closed valves, and the switching valve can change the direction of fluid flow in the liquid-gas separation circuit 400 by opening different subsets of the valves. In this case, the pump 406 does not necessarily need to be a reversible pump to operate in the operating mode and the cleaning mode.

[0142] For example, such as Figure 2As shown, the switching valve 404 may include a set of four valves 404a-404d. In some cases, valve 404a is located between the first port 402 and the pump 406; valve 404b is located between the first port 402 and the fluid outlet 420 of the first chamber 414; valve 404c is located between the second port 410 and the pump 406; and valve 404d is located between the second port 410 and the fluid outlet 420 of the first chamber 414. For example, in operating mode, valves 404a and 404d are open, while valves 404b and 404c are closed. The reaction medium 112 can flow from the first port 402 through valve 404a, pump 406, the fluid inlet 418 and fluid outlet 420 of the liquid-gas separator 408, and valve 404d to the second port 410. For example, in cleaning mode, valves 404a and 404d are closed, while valves 404b and 404c are open. The gas in the gas region 110 of the reaction chamber 102 can flow from the second port 410 through valve 404c, pump 406, fluid inlet 418 and fluid outlet 420 of the liquid-gas separation device 408, and valve 404b to the first port 402.

[0143] In some embodiments, the liquid-gas separation circuit 400 includes a solenoid valve (not shown). The solenoid valve may be located upstream of the liquid-gas separation device 408. The solenoid valve prevents the reaction medium 112 from entering the liquid-gas separation device 408 due to pressure that may accumulate in the reaction medium 112 during the electrochemical generation of NO.

[0144] Figure 4C This is a graphical representation of the concentration of NO in the product gas generated by the NO generating apparatus 100 during multiple stages according to some embodiments of the present disclosure. In this example, the NO generating apparatus 100 may have the same characteristics as described above. Figure 4A The reaction conditions are the same as those described in the example, except that after an initial application of approximately 150 mA of current within a ramp cycle of approximately 2 minutes in multiple stages, a current of 50 mA can be applied to the first electrode 116. The NO generating apparatus 100 may also include a liquid-gas separation circuit 400. In each stage, after the current applied to the first electrode 116 is terminated, the liquid-gas separation circuit 400 can operate in a working mode, circulating the reaction medium 112 through the liquid-gas separator 408 at a flow rate of approximately 0.5 L / min for approximately 10 minutes to reduce or remove dissolved NO in the given reaction medium 112. The liquid-gas separation circuit 400 can then operate in a clean mode, circulating the gas in the gas region 110 through the liquid-gas separator 408 at a flow rate of approximately 1 L / min for approximately 0.5 minutes. Figure 4CAs shown, the NO generating device 100 using reaction medium 112 can generate product gas with a NO concentration of approximately 2000 ppm in five consecutive stages.

[0145] The following provides some examples of NO systems. In some examples, NO system 10 may include NO generating device 100 and carrier gas source 200. NO generating device 100 may include a reaction chamber 102 having a gas region and a liquid region, a reaction medium 112 contained in the liquid region, a cathode and an anode disposed in the reaction medium 112, two sprayers 134, a gas circulation loop 300, and a liquid-gas separation loop 400. Sprayers 134 may be disposed near the two electrodes respectively, and the sprayers are configured to emit bubbles to propagate across the surfaces of the electrodes. Carrier gas source 200 may generate carrier gas 122 from compressed air. Carrier gas source 200 may include a moisture filter and a dust filter to reduce or remove moisture and solids from the compressed air. Carrier gas source 200 may further include a nitrogen generating device 202 having a nitrogen separation membrane to separate N2 from the compressed air. The cathode and anode may be electrically connected to a power source. A power source can apply current or voltage to the cathode, and NO can be generated at or near the surface of the cathode and swept or entrained by the carrier gas 122 into the gas region to generate product gas. A gas recirculation loop 300 can recirculate the product gas from the gas region back to the sprayer. The recirculated gas can be combined with the carrier gas 122 to be introduced into the sprayer. A liquid-gas separation loop 400 can include a liquid-gas separation device 408 to separate NO dissolved in the reaction medium after the application of voltage or current to the cathode is terminated when current or current is applied to the cathode. The liquid-gas separation device 408 can include a separation membrane having a surface area. The liquid-gas separation loop 400 can operate in a working mode during a first cycle and in a clean mode during a second cycle after the first cycle.

[0146] For example, the cathode and anode can be made of platinum. The reaction medium may include approximately 0.01 mol / L of HEPES buffer, approximately 0.01 mol / L of sodium nitrite, and approximately 1 mmol / L of copper-tris(2-pyridylmethyl)amine (CuTPMA). The HEPES buffer can be titrated with a suitable alkaline solution (e.g., NaOH solution) to give the reaction medium a pH of approximately 6 to approximately 8, such as approximately 7.2. An excitation current of approximately 20 mA can be applied to the cathode for approximately 0.5 minutes before applying a current of approximately 10 mA to the cathode. The nitrogen separation membrane of the nitrogen generation device 202 can be made of poly(4-methyl-1-pentene) and can have an average pore size of approximately 0.01 μm. The nitrogen generation device 202 can generate a carrier gas 122 containing approximately 99.0% N2 by volume from compressed air. The carrier gas 122 can be introduced into the sprayer 134 at a flow rate of approximately 50 mL / min. The gas recirculation loop 300 allows the product gas to be recirculated at a flow rate of approximately 0.5 L / min. After a ramp cycle of approximately 10 minutes with current applied to the cathode, the NO generating device 100 can output product gas with a NO concentration of approximately 200 ppm. After the current application to the cathode is terminated, the liquid-gas separation loop 400 can operate in working mode for approximately 10 minutes and then in clean mode for approximately 1 minute. The separation membrane of the liquid-gas separation device 408 can have a diameter of approximately 25,000 cm⁻¹. 2 Surface area.

[0147] For example, the cathode and anode can be made of gold. The reaction medium may include approximately 1 mol / L of MOPS buffer, approximately 1 mol / L of sodium nitrite, and approximately 3 mmol / L of Fe-1,4,7-triazacyclononane. The MOPS buffer can be titrated with a suitable alkaline solution (such as NaOH solution) to give the reaction medium a pH of approximately 6 to approximately 8, such as approximately 7.2. An excitation voltage of approximately 4.2 V can be applied to the cathode for about 1 minute before applying a voltage of approximately 1.4 V to the cathode. The nitrogen separation membrane of the nitrogen generation device 202 can be made of brominated polycarbonate and can have an average pore size of approximately 0.02 μm. The nitrogen generation device 202 can generate a carrier gas 122 containing approximately 99.6% N2 by volume from compressed air. The carrier gas 122 can be introduced into the sprayer 134 at a flow rate of approximately 100 mL / min. The gas circulation loop 300 can recirculate the product gas at a flow rate of approximately 1 L / min. After a ramp cycle of approximately 9 minutes with voltage applied to the cathode, the NO generating device 100 can output product gas with a NO concentration of approximately 1200 ppm. After the voltage application to the cathode is terminated, the liquid-gas separation circuit 400 can operate in working mode for approximately 5 minutes and then in clean mode for approximately 0.5 minutes. The separation membrane of the liquid-gas separation device 408 can have a thickness of approximately 1000 cm⁻¹. 2 Surface area.

[0148] For example, the cathode and anode can be made of carbon. The reaction medium may include approximately 1.5 mol / L Tris buffer, approximately 2 mol / L potassium nitrite, and approximately 4 mmol / L Ti(Me3TACN). The Tris buffer can be titrated with a suitable alkaline solution (such as NaOH solution) to give the reaction medium a pH of approximately 6 to approximately 8, such as approximately 7.2. An excitation current of approximately 500 mA can be applied to the cathode for approximately 1.5 minutes before applying a current of approximately 100 mA to the cathode. The nitrogen separation membrane of the nitrogen generation device 202 can be made of polypropylene and can have an average pore size of approximately 0.012 μm. The nitrogen generation device 202 can generate a carrier gas 122 containing approximately 99.7% N2 by volume from compressed air. The carrier gas 122 can be introduced into the sprayer 134 at a flow rate of approximately 200 mL / min. The gas circulation loop 300 can recirculate the product gas at a flow rate of approximately 1.5 L / min. After a ramp cycle of approximately 6 minutes with current applied to the cathode, the NO generating device 100 can output product gas with a NO concentration of approximately 3000 ppm. After the current application to the cathode is terminated, the liquid-gas separation circuit 400 can operate in working mode for approximately 12 minutes and then in clean mode for approximately 0.9 minutes. The separation membrane of the liquid-gas separation device 408 can have a thickness of approximately 1000 cm⁻¹. 2 Up to approximately 50,000 cm 2 The surface area, for example, approximately 50,000 cm² 2 .

[0149] For example, the cathode and anode can be made of SiO2 coated with glassy carbon. The reaction medium may include approximately 2 mol / L of MOPS buffer, approximately 3 mol / L of sodium nitrite, and approximately 5 mmol / L of chromium-tris(2-pyridylmethyl)amine (CrTPMA). The MOPS buffer can be titrated with a suitable alkaline solution (such as NaOH solution) to give the reaction medium a pH of approximately 6 to approximately 8, such as approximately 7.2. An excitation voltage of approximately 12 V can be applied to the cathode for approximately 2 minutes before applying a voltage of approximately 2 V to the cathode. The nitrogen separation membrane of the nitrogen generation device 202 can be made of polyimide and can have an average pore size of approximately 0.005 μm. The nitrogen generation device 202 can generate a carrier gas 122 containing approximately 99.99% N2 by volume from compressed air. The carrier gas 122 can be introduced into the sprayer 134 at a flow rate of approximately 300 mL / min. The gas recirculation loop 300 allows the product gas to be recirculated at a flow rate of approximately 2 L / min. After a ramp cycle of approximately 5 minutes with voltage applied to the cathode, the NO generating device 100 can output product gas with a NO concentration of approximately 4200 ppm. After the voltage application to the cathode is terminated, the liquid-gas separation loop 400 can operate in working mode for approximately 5 minutes and then in clean mode for approximately 1.5 minutes. The separation membrane of the liquid-gas separation device 408 can have a thickness of approximately 1000 cm⁻¹. 2 Up to approximately 5000cm 2 The surface area, for example, is approximately 37,500 cm². 2 .

[0150] For example, the cathode and anode can be made of conductive glass coated with stainless steel. The reaction medium can include approximately 2.5 mol / L phosphate buffer, approximately 4 mol / L sodium nitrite, and approximately 6 mmol / L manganese-tris(2-pyridylmethyl)amine (MnTPMA). The phosphate buffer can be titrated with a suitable alkaline solution (such as NaOH solution) to give the reaction medium a pH of approximately 6 to approximately 8, such as approximately 7.2. An excitation current of approximately 1.4 A can be applied to the cathode for approximately 2.5 minutes before applying a current of approximately 200 mA to the cathode. The nitrogen separation membrane of the nitrogen generation device 202 can be made of polydimethylsiloxane (PDMS) and can have an average pore size of approximately 0.008 μm. The nitrogen generation device 202 can generate a carrier gas 122 containing approximately 99.8% N2 by volume from compressed air. The carrier gas 122 can be introduced into the sprayer 134 at a flow rate of approximately 400 mL / min. The gas recirculation loop 300 allows the product gas to be recirculated at a flow rate of approximately 2.5 L / min. After a ramp cycle of approximately 4.6 minutes with current applied to the cathode, the NO generating device 100 can output product gas with a NO concentration of approximately 6300 ppm. After the current application to the cathode is terminated, the liquid-gas separation loop 400 can operate in working mode for approximately 20 minutes and then in clean mode for approximately 2 minutes. The separation membrane of the liquid-gas separation device 408 can have a thickness of approximately 1000 cm⁻¹. 2 Up to approximately 5000cm 2 The surface area, for example, approximately 12,500 cm² 2 .

[0151] For example, the cathode and anode can be made of stainless steel coated with an iridium-ruthenium alloy. The reaction medium may include approximately 3 mol / L of borate-borax buffer, approximately 5 mol / L of potassium nitrite, and approximately 7 mmol / L of cobalt-(bis(2-aminoethylpropionidium)propionic acid). The borate-borax buffer can be titrated with a suitable alkaline solution (such as NaOH solution) so that the reaction medium has a pH of approximately 6 to approximately 8, such as approximately 7.2. An excitation voltage of approximately 24 V can be applied to the cathode for approximately 3 minutes before applying a voltage of approximately 3 V to the cathode. The nitrogen separation membrane of the nitrogen generation device 202 can be made of brominated polycarbonate and can have an average pore size of approximately 0.015 μm. The nitrogen generation device 202 can generate nitrogen from compressed air. A carrier gas 122 containing approximately 99.9% N2 by volume is generated. The carrier gas 122 can be introduced into the sprayer 134 at a flow rate of approximately 600 mL / min. The gas recirculation loop 300 can recirculate the product gas at a flow rate of approximately 3 L / min. After a ramp cycle of approximately 5 minutes with voltage applied to the cathode, the NO generating device 100 can output product gas with an NO concentration of approximately 10400 ppm. After the current application to the cathode is terminated, the liquid-gas separation loop 400 can operate in operating mode for approximately 18 minutes and then in clean mode for approximately 1.6 minutes. The separation membrane of the liquid-gas separation device 408 can have a diameter of approximately 1000 cm⁻¹. 2 Up to approximately 5000cm 2 The surface area, for example, approximately 5000 cm² 2 .

[0152] Product gas filtration

[0153] System 10 may include one or more filtration systems or devices to reduce or remove one or more impurities from the product gas. In some embodiments, such as Figure 1 As shown, system 10 includes a filtration system 500 disposed downstream of NO generating device 100. For example, filtration system 500 may be disposed downstream of gas region 110 and / or outlet circuit 124 of NO generating device 100 and in fluid communication with the gas region and / or outlet circuit of NO generating device. Filtration system 500 may reduce or remove one or more impurities, such as moisture and / or solid matter, from the product gas from NO generating device 100. As described herein, moisture may include any liquid in the gaseous or liquid phase that may be present in the product gas, such as water vapor, water droplets, solvent vapor, and solvent droplets.

[0154] The filtration system 500 may include one or more filtration devices or filters. In some embodiments, the filtration system 500 includes one or more solids filters 502. It is contemplated that the solids filters 502 may be configured to filter any type of solids by, for example, modifying or selecting the filter material and / or pore size. In one embodiment, the solids filter 502 may be a salt aerosol filter. In some embodiments, the solids filter 502 includes a membrane filter. The membrane filter may include a polymeric material having a porous structure. For example, the polymeric material may include one or more materials selected from polytetrafluoroethylene (PTEF), polyvinylidene fluoride, polyethersulfone, mixed cellulose esters, polyamide (nylon), nylon 6, and nylon 66. The average pore size of the porous structure can range from about 0.01 μm to about 2 μm, such as from about 0.1 μm to about 0.2 μm, from about 0.2 μm to about 0.4 μm, from about 0.4 μm to about 0.6 μm, from about 0.6 μm to about 0.8 μm, from about 0.8 μm to about 1.0 μm, from about 1.0 μm to about 1.2 μm, from about 1.2 μm to about 1.4 μm, from about 1.4 μm to about 1.6 μm, from about 1.6 μm to about 1.8 μm, from about 1.8 μm to about 2 μm, or combinations thereof.

[0155] In one example, solid material filter 502 may include a component filter made of PTEF with an average pore size of approximately 1.0 μm. In another example, solid material filter 502 may include a component filter made of polyvinylidene fluoride with an average pore size of approximately 0.1 μm. In another example, solid material filter 502 may include a component filter made of polyethersulfone with an average pore size of approximately 2.0 μm. In another example, solid material filter 502 may include a component filter made of nylon 6 with an average pore size of approximately 0.1 μm. In another example, solid material filter 502 may include a component filter made of nylon 66 with an average pore size of approximately 0.8 μm. In yet another example, solid material filter 502 may include a component filter made of mixed cellulose esters with an average pore size of approximately 1.6 μm.

[0156] In some embodiments, the filtration system 500 includes one or more moisture filters 504. Moisture filters 504 can reduce or remove liquids, such as water, from the gas and / or liquid phases. In some embodiments, moisture filters 504 include membrane filters. In some embodiments, the membrane filter includes a polymeric material. The polymeric material may have a porous structure. The polymeric material can absorb liquid vapor and / or liquid droplets. Additionally or alternatively, the polymeric material may be at least partially permeable to liquid vapor and / or liquid droplets. For example, the membrane filter may include Nafion.TM membrane.

[0157] In some embodiments, the filtration system 500 includes one or more additional filters 506. Filters 506 may be disposed downstream of solids filter 502 and / or moisture filter 504 to further remove or reduce impurities, such as moisture and / or solids, from the product gas. In some embodiments, filter 506 includes a membrane filter. In some embodiments, the membrane filter includes a polymeric material. In some embodiments, the membrane filter has a porous structure. For example, the polymeric material of the membrane filter may have a porous structure. The average pore size of the porous structure can range from about 0.01 μm to about 2 μm, such as from about 0.01 μm to about 0.1 μm, from about 0.1 μm to about 0.2 μm, from about 0.2 μm to about 0.3 μm, from about 0.3 μm to about 0.4 μm, from about 0.4 μm to about 0.5 μm, from about 0.5 μm to about 1.0 μm, from about 1.0 μm to about 2 μm, or combinations thereof. In some embodiments, the average pore size of filter 506 is equal to or less than the average pore size of solid material filter 502.

[0158] As described herein, membrane filters used in some embodiments of this disclosure may include at least one membrane layer, which may have any suitable configuration for filtering or separating gases, liquids, and / or solids. For example, the membrane of a membrane filter may be configured for dead-end filtration, wherein fluid can pass through the membrane, and components to be separated from the fluid may be blocked or captured by the membrane. Alternatively, the membrane of a membrane filter may be configured for cross-flow filtration, wherein fluid can pass through the surface of the membrane on the feed side, and components to be separated from the fluid may be retained on the feed side or permeate through the membrane to the permeate side. An example configuration of cross-flow filtration is one or more hollow fibers formed by a membrane.

[0159] For example, the product gas output from the gas region 110 of the NO generating device 100 may include a certain amount of liquid and / or solid impurities, such as water and salt aerosols. This amount of impurities may damage and / or affect the lifespan of downstream devices, such as pump 306 and one or more filters 502-506. In some embodiments, system 500 includes a filtration device 508 disposed downstream of the NO generating device 100. In some embodiments, the filtration device 508 is disposed upstream of pump 306 to reduce or remove liquid and / or solid impurities in the recirculated product gas 303. For example, the product gas output from the gas region 110 of the NO generating device 100 may include one or more impurities, such as water or droplets or vapors of reaction medium 112. In some embodiments, the filtration device 508 is disposed upstream of solids filter 502 and / or moisture filter 504. The filtration device 508 can reduce or remove liquid and / or solid impurities from the product gas before it flows through one or more filters 502-506.

[0160] Figures 5A-5C A filtering device 508 according to some embodiments of the present disclosure is shown. For example... Figures 5A-5C As shown, in some embodiments, the filter device 508 includes a housing 510, an inlet 518, and an outlet 520. In some embodiments, the filter device 508 includes at least one chamber disposed within the housing 510. The inlet 518 and / or the outlet 520 may be in fluid communication with at least one chamber in the housing 510. The housing 510 may have any suitable shape, such as a cylindrical shape. Figure 5C As shown, the inlet 518 can be located at the bottom portion of the housing 510 and is in fluid communication with the chamber. The outlet 520 can be located at the top portion of the housing 510 and is in fluid communication with the chamber.

[0161] In some embodiments, such as Figure 5B As shown, the filter device 508 includes one or more filter chambers 512. The filter chambers 512 can have any suitable shape, such as a cylindrical shape. The filter chambers 512 can be arranged around the longitudinal axis of the housing 510 and can be equidistant or unequally spaced. The filter device 508 can include any suitable number of filter chambers 512, such as 2 to 5 filter chambers. For example, three filter chambers 512 can be equidistantly spaced about 120 degrees around the longitudinal axis of the housing 510.

[0162] Each filter chamber 512 may have an inlet 522 and an outlet 524. The inlet and outlet of one or more filter chambers 512 may define a flow path. One or more filter chambers 512 (e.g., the first filter chamber 512) may have an inlet 522 in fluid communication with an inlet 518 of the housing 510. One or more filter chambers 512 (e.g., the last filter chamber 512) may have an outlet 524 in fluid communication with an outlet 520 of the housing 510. In some embodiments, the filter chamber 512 includes a filter material 516 configured to reduce or remove one or more impurities in the fluid flowing through it. The filter material 516 may fill at least a portion of the filter chamber 512, such as the central portion of the filter chamber 512. The filter material 516 may include any suitable material, such as silicone, sponge, cotton, polypropylene (e.g., PP cotton filter), foam, and foam resin.

[0163] In some embodiments, the filter device 508 includes a feed chamber 526. The feed chamber 526 may be in fluid communication with an inlet 518 for receiving a fluid to be filtered, such as a gas stream. The feed chamber 526 may be in fluid communication with one or more filter chambers 512. For example, the feed chamber 526 may have an outlet in fluid communication with an inlet 522 of a filter chamber 512. In some embodiments, the feed chamber 526 extends through a central portion of the housing 510, forming a cavity between the feed chamber 526 and an inner surface of the housing 510.

[0164] For example, such as Figures 5A-5C As shown, the housing 510 may have a cylindrical shape. The feed chamber 526 may have a cylindrical shape extending along at least a portion of the longitudinal axis of the housing 510. The annular space formed between the feed chamber 526 and the housing 510 may form a cavity. In some embodiments, one or more chambers (such as filter chamber 512) are disposed in the cavity between the feed chamber 526 and the housing 510.

[0165] The filter device 508 can be configured to allow at least some liquid and / or solid impurities in the gas (such as the product gas output from the gas region 110) to be separated from the gas based on, for example, gravity settling or separation. In some embodiments, the inlet 522 of the filter chamber 512 is positioned vertically below the outlet 524, such that liquid and / or solid particles suspended in the gas flowing from the inlet 522 to the outlet 524 can settle out of the gas and settle to the bottom of the filter chamber 512.

[0166] For example, the filter chamber 512 may have an elongated shape (e.g., a cylindrical shape) and may be positioned vertically along its longitudinal axis. In this configuration, the inlet 522 may be located at the bottom or lower portion of the filter chamber 512, while the outlet 524 may be located at the top or upper portion of the filter chamber 512. A gas flow may enter the filter chamber 512 from the inlet 522, move or rise through at least a portion of the filter chamber 512, and reach the outlet 524. As the gas flow moves or rises within the filter chamber 512, it can pass through the filter material 516, and liquid and / or solid impurities suspended in the gas flow can settle and separate from the gas flow.

[0167] In some embodiments, the filtration device 508 includes a buffer chamber 514 in fluid communication with the filter chamber 512. For example, the buffer chamber 514 may be in fluid communication with the filter chamber 512 via an opening or port at the bottom portion of the filter chamber 512. The gas to be filtered (e.g., a gas stream) may flow from the buffer chamber 514 to the filter chamber 512 via the opening or port, rise within the filter chamber 512, and exit from the outlet 524. Liquid and / or solid substances that settle from the gas in the filter chamber 512 may settle to the bottom portion of the filter chamber 512. The settled liquid and / or solids may flow into the buffer chamber 514 and accumulate therein.

[0168] Liquid and / or solid matter accumulated in buffer chamber 514 can be removed from filter device 508 by any suitable means (e.g., by gravity or by pump). The liquid and / or solid matter removed from filter device 508 can be processed or reused. For example, reaction medium 112 precipitated from the product gas from NO generation device 100 can be transported from buffer chamber 514 back to liquid region 108 of reaction chamber 102 and reused.

[0169] In some embodiments, such as Figure 5C As shown, buffer chamber 514 is in fluid communication with feed chamber 526. Fluid can flow from feed chamber 526 to buffer chamber 514 and from buffer chamber 514 to filter chamber 512. For example, the fluid to be filtered (such as a gas stream) can flow from inlet 518 through feed chamber 526, buffer chamber 514 and filter chamber 512 and to outlet 520.

[0170] In some embodiments, such as Figures 5A-5CAs shown, the filtration device 508 includes two or more fluidly connected filter chambers 512 to allow for more than one sedimentation process. For example, the outlet 524 of the first filter chamber 512 may be fluidly connected to the inlet 522 of the second filter chamber 512. Gas can flow through two or more filter chambers 512 to allow liquid impurities and / or solid impurities to settle out of the gas flow as it rises from the inlet 522 to the outlet 524 of each filter chamber.

[0171] In some embodiments, such as Figure 5A and 5B As shown, buffer chamber 514 is fluidly connected to two filter chambers 512. Buffer chamber 514 may have openings or conduits configured to connect to the two filter chambers 512, allowing fluid to flow from inlet 522 in each of the two filter chambers 512 to outlet 524. For example, as... Figure 5B As shown, the outlet 524 of the first filter chamber 512 can be the inlet of the buffer chamber 514, and the inlet 522 of the second filter chamber 512 can be the outlet of the buffer chamber 514. Fluid can flow from the outlet 524 of the first filter chamber 512 to the buffer chamber 514 and from the buffer chamber 514 to the inlet 522 of the second filter chamber 512. In this case, as... Figure 5B As shown, the outlet 524 of the first filter chamber 512 can be located at the top part of the buffer chamber 514, while the inlet 522 of the second filter chamber 512 can be located at the bottom part of the buffer chamber 514.

[0172] The filter device 508 may include one or more other components, such as components for covering or sealing one or more inlets, outlets, and / or chambers of the housing 510. In some embodiments, such as Figure 5A As shown, the filter device 508 includes a seal configured to cover the top side of the buffer chamber 514 to allow gas in the buffer chamber 514 to flow from the buffer chamber 514 to one or more filter chambers 512. In some embodiments, such as Figure 5A As shown, the filter device 508 includes a cover 528. The cover 528 may cover the top side of the housing 510 and the top side of the filter chamber 512 to allow gas in the filter chamber 512 to escape at the outlet 524. The cover 528 may be secured to the housing 510 via any suitable connection, such as by press-fit or using suitable fastening devices (e.g., screw fasteners). In some embodiments, such as Figure 5A As shown, the filter device 508 includes a sealing ring configured to form a seal around the inlet 518.

[0173] pressure vessel

[0174] The flow rate and / or NO concentration of the product gas generated by NO generating device 100 may vary due to changes in one or more conditions, such as temperature, current or voltage applied to the electrodes, side reactions, electrode degradation, or changes in the concentration of nitrite source and catalyst in reaction medium 112. System 10 may include one or more devices or systems (e.g., pressure vessels) to stabilize the flow rate and / or NO concentration of the product gas generated by NO generating device 100. Such devices or systems may allow system 10 to provide a stable NO supply.

[0175] In some embodiments, such as Figure 1 As shown, system 10 includes a pressure vessel 600. Pressure vessel 600 may be located downstream of and fluidly connected to the NO generating device 100. In some embodiments, pressure vessel 600 receives product gas from outlet circuit 124 of the NO generating device 100. One or more filters of filtration system 500 may be located downstream of the NO generating device 100 and upstream of pressure vessel 600. Product gas from NO generating device 100 may flow from outlet circuit 124 through one or more filters of filtration system 500 to pressure vessel 600. Before the product gas enters pressure vessel 600, filtration system 500 may reduce or remove one or more impurities, such as moisture and / or solid matter (e.g., salt aerosols), from the product gas.

[0176] In some embodiments, such as Figure 6A As shown, pressure vessel 600 includes a body 602, a gas inlet 612, and a gas outlet 614. The body 602 can have any suitable shape, such as a cylindrical shape, configured to enclose an internal cavity. The gas inlet 612 and gas outlet 614 are in fluid connection to the internal cavity of the body 602. For example, as... Figure 6A As shown, the gas inlet 612 and / or the gas outlet 614 may each have an opening or port provided on the body 602.

[0177] Pressure vessel 600 can receive and store product gas from NO generating device 100 during a pressure holding period. At the end of the pressure holding period, the pressure in pressure vessel 600 can be increased to a predetermined level or range. Additionally or alternatively, at the end of the pressure holding period, the concentration of NO in the product gas contained in pressure vessel 600 can be increased to a predetermined level or range. The pressure holding period can be predetermined and / or adjusted. In some embodiments, after the pressure holding period, the product gas can be released from pressure vessel 600. The NO concentration of the product gas released from pressure vessel 600 can increase during a ramp period and can reach a steady state at the end of the ramp period or after the end of the ramp period.

[0178] In some embodiments, pressure vessel 600 is configured to shorten pressure holding and ramp cycles to allow for a more rapid or immediate provision of a stable NO supply. For example, pressure vessel 600 may include one or more flow paths within the internal cavity of body 602. These flow paths may include tortuous, such as meandering, flow paths. One or more flow paths may allow the pressure and / or NO concentration of the product gas in at least a portion of the internal cavity of body 602 to rapidly reach a steady state. For example, one or more flow paths may allow new gas (e.g., product gas) to enter the internal cavity to rapidly purge or deplete old gas (e.g., air or nitrogen) previously present in at least a portion of the internal cavity. Additionally or alternatively, one or more flow paths may reduce or eliminate uneven mixing of new and old gases.

[0179] As described herein, a tortuous flow path (e.g., a meandering flow path) can refer to an indirect flow path extending from a first point to a second point in an arbitrary direction in three-dimensional space. For example, a tortuous flow path can refer to an indirect flow path extending from a first point to a second point through the cross-section and / or longitudinal plane of the pressure vessel 600.

[0180] For example, pressure vessel 600 may allow a pressure holding period of less than about 60 minutes, such as less than about 1 minute, less than about 5 minutes, less than about 10 minutes, less than about 20 minutes, less than about 30 minutes, less than about 40 minutes, or less than about 50 minutes. For example, pressure vessel 600 may allow a ramp period of less than about 20 minutes, such as less than about 1 minute, less than about 2 minutes, less than about 3 minutes, less than about 4 minutes, less than about 5 minutes, less than about 8 minutes, or less than about 10 minutes.

[0181] Figures 6A-6CThese are various views of a pressure vessel 600 according to some embodiments of the present disclosure. In some embodiments, the pressure vessel 600 includes one or more panels or partitions 604 that define multiple fluidly connected regions within an internal cavity. In various configurations, the fluidly connected regions may form a tortuous flow path through the pressure vessel 600, such as a meandering flow path. For example, multiple panels 604 may divide the internal cavity into a first region 606 and a second region 608. The first region 606 and the second region 608 may be fluidly connected via, for example, an opening, a port, or a conduit. Fluid entering the pressure vessel 600 (e.g., product gas) may enter the first region 606 and flow from the first region 606 to the second region 608 via a tortuous flow path. Alternatively, fluid entering the pressure vessel 600 (e.g., product gas) may enter the first region 606 and exit the pressure vessel without flowing into or through the second region 608, i.e., it may bypass the second region 608. The tortuous flow path may allow new gas entering the pressure vessel 600 to effectively purge or deplete previously present old gas in the pressure vessel. The tortuous flow path also allows the pressure in one or more regions of the pressure vessel 600 to reach steady state in a shorter period than is required for the pressure in the entire pressure vessel to reach steady state.

[0182] In some embodiments, the first region 606 is fluidly connected to a gas inlet 612 and a gas outlet 614. For example, the gas inlet 612 may be fluidly connected to a first opening or a first port provided in the first region 606. The gas outlet 614 may be fluidly connected to a second opening or a second port provided in the first region 606. Gas may flow from the gas inlet 612 to the gas outlet 614 via at least a portion of the first region 606.

[0183] The first region 606 can be configured to allow gas entering the gas inlet 612 to rapidly fill at least a portion of the first region 606. In some embodiments, the first region 606 is divided into a plurality of chambers defining a first flow path 618. For example, one or more panels 604 may be disposed in the first region 606 and divide the first region into a plurality of chambers. The first flow path 618 may be a tortuous flow path, such as a meandering flow path. A tortuous flow path can allow new gas entering the first region 606 to rapidly purge or deplete old gas previously present in one or more chambers of the first region 606. This can allow the pressure in one or more chambers of the first region 606 to reach steady state in a shorter period than the time required for the pressure in one or more chambers of the first region 606 and the second region 608 to reach steady state. For example, it may take less than about 5 minutes for one or more chambers of the first region 606 to reach steady-state pressure, but it may take about 20 to about 30 minutes for the internal cavities of the body 602 of the pressure vessel 600 to reach steady-state pressure.

[0184] For example, such as Figure 6B and 6C As shown, gas inlet 612 and gas outlet 614 can be fluidly connected to the first chamber 606a. Product gas can flow from gas inlet 612 to gas outlet 614 via at least a portion of the first chamber 606a. Product gas received by gas inlet 612 can enter and rapidly fill the first chamber 606a of the first region 606, thereby allowing the pressure in the first chamber 606a to reach a steady state within a short time. This reduces the pressure holding time before the product gas is released from gas outlet 614.

[0185] The first chamber 606a can have any suitable shape and / or size, which allows the pressure of the product gas in the chamber to reach a steady state within a short pressure holding time. For example, the first chamber 606a can have an elongated shape and a narrow cross-section extending along the longitudinal dimension of the body 602. The first chamber 606a can have any suitable size or volume. For example, the volume of the first chamber 606a can be 50% or less of the internal cavity of the body 602. For example, the pressure vessel 600 can have an internal volume of approximately 800 mL, and the first chamber 606a can have a volume of approximately 10 mL to approximately 200 mL. In one example, after receiving and holding the product gas for a pressure holding period of approximately 20 minutes, the pressure vessel 600 can release the product gas at the gas outlet 614, and the NO concentration in the released product gas can reach a steady state within approximately 10 minutes.

[0186] In some embodiments, the second region 608 is fluidly connected to the first region 606 via a channel 610. The second region 608 may receive and store gas flowing out of the first region 606. The second region 608 may include a tortuous flow path, such as a meandering flow path. For example, the second region 608 may be configured to allow gas from the first region 606 to fill at least a portion of the second region 608.

[0187] In some embodiments, the second region 608 is divided into a plurality of chambers defining a second flow path 620. For example, one or more panels 604 may be disposed in the second region 608 and divide the second region into a plurality of chambers. The second flow path 620 may be in fluid communication with a first flow path 618, for example, via a channel 610. The second flow path 620 and the first flow path 618 may form a continuous flow path. The second flow path 620 may be a tortuous flow path, such as a meandering flow path. A tortuous flow path may allow new gas entering the second region 608 from the first region 606 to purge or deplete old gas previously present in one or more chambers of the second region 608. This may also allow the pressure in one or more chambers of the second region 608 to reach a steady state before the pressure throughout the second region 608 reaches a steady state.

[0188] The chambers of the second region 608 can be referred to as gas storage units. One or more chambers of the second region 608 can be further divided into one or more sub-chambers to further reduce the volume in each gas storage unit. This can reduce or eliminate uneven mixing of new and old gases in the second region 608, and this can reduce the time required for the pressure in the second region 608 to reach steady state. For example, the chambers of the second region 608 can each be divided into two or more fluidly connected sub-chambers by one or more partitions 609. The partitions 609 can have any suitable structure for guiding gas flow in the chamber, such as panels or plates. For example, as Figure 6B and 6C As shown, two or more partitions 609 may each extend along at least a portion of the longitudinal axis of the pressure vessel 600 and may be radially spaced apart, such that the sub-chambers are fluidly connected via a space 611 between the partitions.

[0189] As described herein, the fluidly connected chambers in the first region 606 or the second region 608 can have any suitable configuration to define flow paths that allow new gas to purge or deplete previously present old gas in one or more chambers of that region. For example, as Figure 6CAs shown, the inlet and outlet of a chamber (e.g., the first chamber 606a) may be separated along at least one dimension (e.g., horizontal and / or vertical). This configuration allows new gas entering the chamber to flow from the inlet through the chamber along at least one dimension to the outlet, to purge or deplete previously present old gas in the chamber.

[0190] The second region 608 can be used as a reservoir for storing product gases. For example, when the flow rate of product gas received at gas inlet 612 is higher than the flow rate of product gas released at gas outlet 614, additional product gas can flow from the first region 606 to the second region 608 for storage. When the flow rate of product gas received at gas inlet 612 is lower than the flow rate of product gas released at gas outlet 614, the product gas stored in the second region 608 can flow from the second region 608 to the first region 606 to supplement the product gas flow. In this case, the pressure vessel 600 can reduce variations in the pressure, flow rate, and / or NO concentration of the product gas released at gas outlet 614. This may be advantageous in providing a stable NO supply, such as when NO generation may vary due to various conditions. It may also be advantageous in providing NO supply at the desired pressure, flow rate, and / or concentration as needed. The second region 608 can also be used as a backup source of NO. For example, in response to an anomaly in the NO generating device 100 generating NO and / or transporting NO in the system 10, the product gas stored in the second region 608 can be released to continue or supplement the NO supply.

[0191] In some embodiments, pressure vessel 600 includes a pressure relief valve 622. The pressure relief valve 622 is configured to control the pressure in pressure vessel 600 to not exceed a threshold. This threshold may be a predetermined safety threshold. The pressure relief valve 622 may be normally closed, for example, by the force of a spring. The pressure relief valve 622 may open when the pressure in one or more regions of pressure vessel 600 exceeds the threshold. In some embodiments, the pressure relief valve 622 is in fluid communication with a second region 608. Figure 1 As shown, the product gas released from the pressure relief valve 622 can be transported from the pressure vessel 600 to the waste gas treatment device 700.

[0192] In some embodiments, system 10 includes one or more pressure sensors to measure pressure in one or more regions or chambers of pressure vessel 600. In some embodiments, pressure sensor 624 may be configured to measure pressure in a first region 606, such as pressure in a first chamber 606a of the first region 606. The measurement by pressure sensor 624 may indicate the pressure of product gas released from gas outlet 614 to a downstream system or device. In some embodiments, one or more pressure sensors (not shown) may be configured to measure pressure in a second region 608. The measurement by such pressure sensor may indicate the amount of product gas stored in the second region 608.

[0193] In some embodiments, pressure vessel 600 includes a purge valve 626. The purge valve 626 can be used to purge or deplete gas, such as product gas, from one or more regions of the internal cavity of pressure vessel 600. For example, the purge valve 626 may be in fluid communication with a first region 606 or a second region 608. Figure 1 As shown, the product gas released from the purge valve 626 can be transported from the pressure vessel 600 to the waste gas treatment device 700. In some embodiments, such as Figure 1 As shown, NO sensor 628 is located downstream of purge valve 626 and configured to measure the NO concentration of the product gas released from purge valve 626. The measurement value of NO sensor 628 can indicate whether the product gas has been purged or depleted from one or more areas of pressure vessel 600.

[0194] In some embodiments, such as Figure 1 As shown, system 10 includes one or more flow control devices 630 to control the flow rate of product gas released from pressure vessel 600. Flow control devices 630 may be located downstream of and in fluid communication with gas outlet 614. Flow control devices 630 may include flow meters and / or flow controllers, such as flow control valves. In some embodiments, system 10 includes a first flow control device 630 and a second flow control device 630. The first flow control device 630 may be selected to measure and / or adjust the flow rate within a first range, and the second flow control device 630 may be selected to measure and / or adjust the flow rate within a second range below the first range. Flow control devices 630 may be connected to and / or controlled by one or more other components of system 10 (such as venting circuit 900), as described below.

[0195] Waste gas treatment

[0196] System 10 may generate waste gas before, during, and / or after NO generation and / or transport. For example, waste gas may be generated during the separation of NO from reaction medium 112 via liquid-gas separator 408. Additionally, waste gas may be generated, for example, by releasing product gas from pressure relief valve 622 of pressure vessel 600. The waste gas of system 10 may include one or more components, such as NO, carrier gas, moisture, and other nitrogen oxides that may be generated during NO generation and / or transport. For example, during NO generation or transport in system 10, NO may be oxidized to nitrogen dioxide (NO2).

[0197] Nitrogen oxides (also known as NO) x For example, NO and NO2, if released directly from system 10 into the environment, could cause air pollution and / or health risks. In some embodiments, such as Figure 1 As shown, system 10 includes one or more exhaust gas treatment devices 700 to treat exhaust gases before they are released from system 10. The exhaust gas treatment devices 700 can reduce or remove one or more nitrogen oxides in the exhaust gases, thereby reducing or eliminating the potential air pollution and / or risk of exposure to nitrogen oxides.

[0198] In some embodiments, the exhaust gas treatment device 700 is located downstream of and in fluid communication with the liquid-gas separator 408. The exhaust gas treatment device 700 can receive a mixed gas from the outlet 426 of the liquid-gas separator 408. The mixed gas may include a scavenged gas and one or more nitrogen oxides (such as NO and NO2). In some embodiments, the exhaust gas treatment device 700 is located downstream of the pressure vessel 600 and in fluid communication with the pressure relief valve 622. When the pressure in the pressure vessel 600 reaches or exceeds a threshold, the exhaust gas treatment device 700 can receive product gas released from the pressure relief valve 622. The product gas may include a carrier gas and one or more nitrogen oxides (such as NO and NO2).

[0199] In some embodiments, exhaust gases from pressure vessel 600 and liquid-gas separator 408 can be treated by the same exhaust gas treatment device 700. For example, system 10 may include a tee connector 702 disposed upstream of exhaust gas treatment device 700 and downstream of pressure vessel 600 and liquid-gas separator 408. Exhaust gases from pressure vessel 600 and liquid-gas separator 408 can combine at tee connector 702 and flow to the same exhaust gas treatment device 700. Tee connector 702 may include any suitable structure, such as a tee fitting or tee valve.

[0200] In some embodiments, when exhaust gas passes through the exhaust gas treatment device 700, the exhaust gas treatment device 700 reduces or removes one or more nitrogen oxides in the exhaust gas. In some embodiments, the exhaust gas treatment device 700 includes a body, an inlet, and an outlet. The inlet and outlet are in fluid communication with a cavity defined by the body. In some embodiments, at least a portion of the cavity is filled with filter material that can reduce or remove one or more nitrogen oxides when exhaust gas passes through the filter material. For example, the filter material may include materials configured to absorb one or more nitrogen oxides (NOx). x One or more absorbent materials (such as NO and NO2).

[0201] In some embodiments, the absorbent material comprises a substrate prepared using an absorbent capable of reacting with one or more nitrogen oxides. For example, the substrate may be coated with an oxidizing agent. The substrate may have any suitable configuration to provide the surface area for the absorbent to react with one or more nitrogen oxides. For example, the substrate may comprise one or more materials selected from molecular sieves, silica gel, alumina, sponge, cotton, foam resin, silica, and activated carbon. For example, the absorbent may comprise one or more materials selected from permanganate, persulfate, chromate, and dichromate.

[0202] In some embodiments, the exhaust gas treatment device 700 includes a plurality of baffles configured to define fluid paths. In some embodiments, at least a portion of the flow path is filled with filter material. The flow path can be tortuous, such as a meandering flow path. For example, the plurality of baffles may extend from the wall of the cavity in an alternating manner to define a meandering flow path. The tortuous flow path may extend along one or more dimensions. The tortuous flow path can increase the contact between the exhaust gas and the filter material to allow for a reduction or removal of more nitrogen oxides as the exhaust gas passes through the device.

[0203] Figures 7A-7C These are various views of an exhaust gas treatment apparatus 700 according to some embodiments of the present disclosure. Figures 7A-7C As shown, in some embodiments, the exhaust gas treatment device 700 includes a body 703, an inlet 722, and an outlet 724. The inlet 722 and outlet 724 are in fluid communication with a cavity 706 defined by the body 703. The body 703 may have any suitable shape, configuration, and / or size. For example, the body 703 may have a cylindrical shape.

[0204] In some embodiments, the body 703 has a first side 718 and a second side 720. An inlet 722 and an outlet 724 may be located on opposite sides or the same side of the body 703. For example, the inlet 722 may be located on the first side 718, while the outlet 724 may be located on the second side 720. Alternatively, both the inlet 722 and the outlet 724 may be located on either the first side 718 or the second side 720. In some embodiments, the body 703 includes an inner housing 708 and an outer housing 710 extending from the first side 718 to the second side 720. The inner housing 708 and the outer housing 710 may define an annular cavity 706. The inner housing 708 and the outer housing 710 may have any suitable dimensions. For example, the diameter of the outer housing 710 may range from 120 mm to 160 mm, while the diameter of the inner housing 708 may range from 80 mm to 120 mm.

[0205] In some embodiments, such as Figure 7C As shown, cavity 706 is divided by wall 716, which extends between inner housing 708 and outer housing 710 and from a first side 718 to a second side 720. Inlet 722 and outlet 724 may be located near opposite sides of wall 716. At least a portion of cavity 706 may be filled with filter material (not shown). Exhaust gas passing through exhaust gas treatment device 700 may flow from inlet 722 through cavity 706 to outlet 724.

[0206] In some embodiments, the exhaust gas treatment device 700 includes a plurality of baffles. The baffles may have any configuration defining a tortuous flow path 704 (e.g., a meandering flow path) within the cavity 706. In some embodiments, such as Figure 7C As shown, the first set of baffles 712 can extend between the first side 718 and the second side 720 and from the inner housing 708 toward the outer housing 710, while the second set of baffles 714 can extend between the first side 718 and the second side 720 and from the outer housing 710 toward the inner housing 708. The baffles 712 and 714 can extend any suitable distance between the inner housing 708 and the outer housing 710 to guide the exhaust gas flow. For example, the distance between the baffle 712 and the outer housing 710 and / or the distance between the baffle 714 and the inner housing 708 can be in the range of 2 mm to 8 mm.

[0207] In some embodiments, the first set of partitions 712 and the second set of partitions 714 may be arranged in an alternating manner. For example, as Figure 7CAs shown, the first set of baffles 712 can be evenly distributed around the circumference of the inner housing 708, while the second set of baffles 714 can be evenly distributed around the circumference of the outer housing 710, offset from the first set of baffles 712. The exhaust gas treatment device 700 can include any suitable number of baffles, such as 2 to 16 baffles. For example, the number of the first set of baffles 712 and / or the second set of baffles 714 can be in the range of 2 to 8. The number of the first set of baffles 712 and the second set of baffles 714 can be the same or different. It is conceivable that the exhaust gas treatment device 700 can include any suitable number of baffles, with or without providing suitable filter material.

[0208] Exhaust gas can flow from inlet 722 to outlet 724 through a tortuous flow path 704. The tortuous flow path 704 may be filled with filter material. As the exhaust gas passes through the filter material in the flow path 704, one or more nitrogen oxides in the exhaust gas can be absorbed. The exhaust gas can exit the exhaust gas treatment device 700 from outlet 724 and can be released into the environment with or without further treatment.

[0209] Reduce and / or remove toxic nitrogen oxides

[0210] NO can be oxidized into one or more toxic nitrogen oxides (such as NO2), which can pose health risks if delivered to a patient along with NO. In some embodiments, system 10 includes a gas converter 800. The gas converter 800 can convert some or all of the potentially toxic nitrogen oxides (such as NO2) that may be present in the product gas into NO as the product gas passes through it. The gas converter 800 can reduce the potential risk of exposure to toxic nitrogen oxides and can increase NO production by converting other nitrogen oxides in the product gas back into NO.

[0211] In some embodiments, the gas converter 800 is located downstream of and in fluid communication with the NO generating device 100. In some embodiments, the gas converter 800 is located downstream of and in fluid communication with the filtration system 500. In some embodiments, the gas converter 800 is located downstream of and in fluid communication with the pressure vessel 600. Figure 8A This is an exploded view of a gas converter according to some embodiments of the present disclosure. In some embodiments, such as Figure 8AAs shown, the gas converter 800 includes a body 808, an inlet 818, and an outlet 820. The inlet 818 and outlet 820 are in fluid communication with a cavity defined by the body 808. The body 808 can have any suitable shape. In some embodiments, the body 808 has a cylindrical shape extending between a first side and a second side. Two end caps 806 can cover the first and second sides of the body 808. The inlet 818 and outlet 820 can be located at the same end cap 806 or at different end caps 806.

[0212] In some embodiments, the gas converter 800 includes one or more membrane filters 810 and filter retainers 812. The filter retainer 812 may be configured to position the membrane filter 810 between an end cap 806 and a body 808. The membrane filter 810 may reduce or remove one or more impurities, such as moisture and solids, from the product gases entering and / or leaving the gas converter 800.

[0213] In some embodiments, at least a portion of the cavity is filled with a filter material that can absorb one or more toxic nitrogen oxides, such as NO2, when the product gas passes through it. For example, the filter material may include soda lime particles. In some embodiments, at least a portion of the cavity is filled with a filter material that can convert one or more toxic nitrogen oxides (such as NO2) into NO when the product gas passes through it. In some embodiments, the filter material includes a substrate configured to carry a reducing agent. For example, the surface of the substrate may be prepared using a reducing agent, such as by application, treatment, or coating. The reducing agent may react with one or more nitrogen oxides and reduce them to NO. The substrate may have any suitable configuration to provide surface area for carrying the reducing agent. For example, the substrate may include one or more materials selected from molecular sieves, silica gel, alumina, sponge, cotton, and foam resin. For example, the reducing agent may include one or more antioxidants, such as vitamin A, vitamin E, and vitamin C. As used herein, vitamin C may also be referred to as ascorbic acid or ascorbate.

[0214] Filter materials can be prepared using any suitable method or process. For example, a solution of one or more reducing agents can be prepared. This solution can be an aqueous solution or an organic solution, and it can be a saturated solution of one or more reducing agents. A certain amount of substrate can be added to the solution and mixed uniformly. The substrate can then be removed from the solution and dried at a drying temperature for a period of time to allow the solvent to evaporate. Based on one or more conditions, such as the type of material used and the desired reducing power, any suitable amount of reducing agent and substrate can be selected. For example, a substrate of approximately 100g per portion can be prepared using an amount of reducing agent ranging from approximately 5g to approximately 50g.

[0215] In one example, approximately 25g of vitamin C can be used to coat approximately 100g of alumina particles. In another example, approximately 5g of vitamin A can be used to prepare approximately 100g of cotton. In another example, approximately 5g of vitamin E can be used to prepare approximately 100g of foam resin. In another example, approximately 30g of vitamin C can be used to prepare approximately 100g of molecular sieve. In another example, approximately 20g of vitamin A can be used to prepare approximately 100g of sponge material. In another example, approximately 15g of vitamin E can be used to prepare approximately 100g of silica gel.

[0216] The drying temperature can range from about 40°C to about 150°C, such as from about 40°C to about 50°C, from about 50°C to about 60°C, from about 60°C to about 70°C, from about 70°C to about 80°C, from about 80°C to about 90°C, from about 90°C to about 100°C, from about 100°C to about 110°C, from about 110°C to about 120°C, from about 120°C to about 130°C, from about 130°C to about 140°C, from about 140°C to about 150°C, or combinations thereof. The drying time can range from about 0.1h to about 10h, such as from about 0.1h to about 0.2h, from about 0.2h to about 0.5h, from about 0.5h to about 1h, from about 1h to about 2h, from about 2h to about 3h, from about 3h to about 4h, from about 4h to about 5h, from about 5h to about 6h, from about 6h to about 7h, from about 7h to about 8h, from about 8h to about 9h, from about 9h to about 10h, or combinations thereof.

[0217] In some embodiments, such as Figures 8A-8B As shown, the gas converter 800 has a cavity divided into multiple chambers 816, each with an inlet and an outlet. The inlet of the first chamber may be fluidly connected to an inlet 818, while the outlet of the last chamber may be fluidly connected to an outlet 820. The inlets and outlets of chambers 816 may be fluidly connected to define a flow path 802. Filter material may fill at least a portion of each chamber, for example, from the chamber inlet to the outlet. The inlet and outlet of each chamber may be positioned at opposite ends, such that gas passing through the chamber can flow from the inlet, through the chamber, through the filter material, and to the outlet.

[0218] The flow path 802 can be a tortuous flow path, such as a meandering flow path. The tortuous flow path in the cavity of the body 808 can increase the contact between the product gas and the filter material, allowing more nitrogen oxides to be reduced to NO as the product gas passes through the device within a given cavity volume.

[0219] The chambers within the gas converter 800 can have any suitable configuration. For example, one or more panels 814 can be disposed on both sides of the body 808 and extend between them. The panels 814 can be arranged equidistantly or unequally spaced around the longitudinal axis of the body 808. Each panel 814 can extend radially from the longitudinal axis to the inner wall of the body 808. For example, the panels 814 can uniformly divide the cavity into a plurality of elongated chambers 816 extending between the two sides of the body 808 and arranged around the longitudinal axis of the body 808. Any suitable number of panels 814 can be used. For example, if the panels 814 are arranged around the longitudinal axis of the body 808, an odd number of panels 814 can divide the cavity into an odd number of chambers, and the inlet 818 and outlet 820 can be located at opposite end caps 806. Alternatively, an even number of panels 814 can divide the cavity into an even number of chambers, and the inlet 818 and outlet 820 can be located at the same end cap 806.

[0220] In one example, the cavity of the gas converter 800 can be evenly divided into three elongated chambers, such as... Figures 8A-8B As shown. Each chamber can be filled with filter material. For example, the filter material can be prepared using aluminosilicate glass particles with an average diameter of approximately 0.2 mm and vitamin C. First, approximately 5 grams of vitamin C can be dissolved in 100 grams of water to prepare a saturated aqueous solution of vitamin C. 100 grams of aluminosilicate glass particles can be added to the solution and mixed evenly. The aluminosilicate glass particles can be dried at approximately 100°C for approximately 0.5 hours. This gas converter 800 can be used to process a gas stream containing 100 ppm NO2 at a flow rate of 1.0 L / min for approximately 90 hours. Approximately 100% of the NO2 in the gas stream can be converted to NO.

[0221] Alternatively, a filter material can be prepared using silica gel particles with an average diameter of approximately 3 mm and vitamin E. First, approximately 15 grams of vitamin E can be prepared into a saturated solution. Approximately 100 grams of silica gel particles can be added to the solution and mixed thoroughly. The silica gel particles can be dried at approximately 50°C for about 5 hours. The gas converter 800 can then be used to process a gas stream containing 500 ppm NO2 at a flow rate of 4.0 L / min for approximately 5 hours. Approximately 100% of the NO2 in the gas stream can be converted to NO.

[0222] In another example, the cavity of the gas converter 800 can be evenly divided into four elongated chambers, with... Figures 8A-8B The illustrated embodiment is similar. Each chamber can be filled with filter material. The filter material can be prepared using molecular sieve particles with an average diameter of approximately 5 mm and vitamin A. First, approximately 25 grams of vitamin A can be prepared into a saturated solution. Approximately 100 grams of molecular sieve particles can be added to the solution and mixed uniformly. The molecular sieve particles can be dried at approximately 80°C for approximately 2 hours. This gas converter 800 can be used to process a gas stream containing 200 ppm NO2 at a flow rate of 2.0 L / min for approximately 70 hours. Approximately 100% of the NO2 in the gas stream can be converted to NO. Alternatively, the filter material can be prepared using alumina particles with an average diameter of approximately 6 mm and vitamin C. Approximately 35 grams of vitamin C can be prepared into a saturated solution. Alumina particles can be added to the solution and mixed uniformly. The alumina sieve particles can be dried at approximately 120°C for approximately 0.25 hours. This gas converter 800 can be used to process a gas stream containing 500 ppm NO2 at a flow rate of 1.0 L / min for approximately 125 hours. It can convert approximately 100% of the NO2 in a gas stream into NO.

[0223] In another example, the cavity of the gas converter 800 can be evenly divided into five elongated chambers, with... Figures 8A-8B The illustrated embodiment is similar. Each chamber can be filled with filter material. The filter material can be prepared using sponge and vitamin E. Approximately 40 grams of vitamin E can be prepared into a saturated solution. Approximately 100 grams of sponge can be immersed in the solution. The sponge can be dried at approximately 150°C for approximately 0.2 hours. This gas converter 800 can be used to process a gas stream containing 800 ppm NO2 at a flow rate of 3.0 L / min for approximately 12 hours. Approximately 100% of the NO2 in the gas stream can be converted to NO. Alternatively, the filter material can be prepared using cotton and vitamin A. Approximately 50 grams of vitamin A can be prepared into a saturated solution. Approximately 100 grams of cotton can be immersed in the solution. The cotton can be dried at approximately 70°C for approximately 3 hours. This gas converter 800 can be used to process a gas stream containing 400 ppm NO2 at a flow rate of 4.0 L / min for 35 hours. Approximately 100% of the NO2 in the gas stream can be converted to NO.

[0224] In some embodiments, the product gas released from the gas converter 800 may be the output gas of the system 10. The quality and / or flow rate of the system's output gas can be monitored. For example, the concentrations of NO, NO2, and moisture can be monitored. In some embodiments, a flow meter is used to monitor the flow rate of the output gas of the system 10.

[0225] NO delivery and / or monitoring

[0226] The NO generated by System 10 can be used for various NO-based therapies. For example, the NO generated by System 10 can be used for NO inhalation therapy. The NO generated by System 10 can be delivered to the patient with or without another gas (such as oxygen). For example, the NO generated by System 10 can be delivered to the patient via an airflow or oxygen flow provided by a ventilator.

[0227] In some embodiments, such as Figure 1 As shown, system 10 includes a ventilation circuit 900 for delivering inhaled NO to a patient. In some embodiments, the ventilation circuit 900 is located downstream of and in fluid communication with a pressure vessel 600. The ventilation circuit 900 may also be located downstream of and in fluid communication with a gas converter 800. The ventilation circuit 900 may be configured to connect system 10 to a breathing apparatus or system for delivering NO in any suitable manner. For example, the ventilation circuit 900 may connect system 10 to a ventilator, nebulizer, positive pressure airway compressor, oxygen supply, etc.

[0228] Figure 9 This is a schematic diagram of a ventilation circuit 900 of a system 10 according to some embodiments of the present disclosure. In some embodiments, the ventilation circuit 900 includes an inspiratory circuit 904 and an expiratory circuit 922. The inspiratory circuit 904 may be configured to fluidly connect to a ventilator 906, and the inspiratory circuit delivers a gas stream (such as an air stream or an oxygen stream) from the ventilator 906 to the patient 910 via a mask or tube. The expiratory circuit 922 delivers exhaled gas from the patient 910 to the ventilator 906.

[0229] In some embodiments, such as Figure 9 As shown, the ventilation circuit 900 includes a port 902 configured to receive a NO supply. For example, port 902 may be located along and in fluid communication with an inhalation circuit 904. In some embodiments, port 902 is located downstream of and in fluid communication with a pressure vessel 600 and / or a gas converter 800. NO supplied from pressure vessel 600 may be mixed with and / or entrained by oxygen or air flowing through inhalation circuit 904 to form a gas mixture 907, which is then delivered to patient 910. In some embodiments, a humidifier 908 is located downstream of port 902 and may be used to humidify the gas mixture 907 before it is delivered to patient 910.

[0230] In some embodiments, the ventilation circuit 900 includes a flow controller 916. The flow controller 916 may be located upstream of port 902 and is configured to control the flow rate of gas entering port 902 (e.g., NO-containing product gas from pressure vessel 600 or gas converter 800). The flow controller 916 may include an inlet port, an outlet port, a flow sensor, and a control valve. In some embodiments, the flow controller 916 is a mass flow controller.

[0231] In some embodiments, the ventilation circuit 900 includes a control device 918. The control device 918 may communicate with a flow controller 916 via a wired or wireless connection. The control device 918 may send control signals to the flow controller 916 to adjust the flow rate of the gas entering port 902. For example, the control device 918 may receive sensor signals from the flow controller 916 indicating the flow rate of the product gas entering port 902, and the control device may generate control signals in response to the received sensor signals. Control signals may be sent from the control device 918 to the flow controller 916 to adjust the flow rate of the gas entering port 902.

[0232] In some embodiments, the ventilation circuit 900 includes a flow sensor 905 configured to measure the flow rate of an air or oxygen stream output from the ventilator 906. The flow sensor 905 may be positioned along the inhalation circuit 904, for example, upstream of port 902. A control device 918 may communicate with the flow sensor 905 via a wired or wireless connection. The control device 918 may send a control signal to a flow controller 916 to adjust the flow rate of the gas stream entering port 902 based on the sensor signal from the flow sensor 905. For example, the control device 918 may receive a sensor signal from the flow sensor 905 indicating the flow rate of the oxygen stream output from the ventilator 906, and the control device may generate a control signal in response to the received sensor signal. The control signal may be sent to the flow controller 916 to adjust the flow rate of a product gas entering port 902 to mix with the oxygen stream, thereby allowing adjustment of the NO concentration in the mixed gas delivered to the patient 910.

[0233] In some embodiments, the ventilation circuit 900 includes one or more gas sensors. The gas sensors can be any suitable sensor configured to detect one or more types of gases, and the gas sensor can measure the concentration of one or more components (such as NO, NO2, O2, and moisture) in the gas mixture 907. For example, the gas sensors can be electrochemical gas sensors, infrared gas sensors, or thermal conductivity gas sensors.

[0234] In some embodiments, the ventilation circuit 900 includes a sampling port 912. The sampling port 912 may be located along the inhalation circuit 904 (e.g., downstream of the humidifier 908) and in fluid communication with that inhalation circuit. The sampling port 912 may also be located upstream of an applicator (e.g., a tube within a mask or trachea). Sampling gas or a stream of sampling gas from the sampling port 912 can be used to measure the concentrations of various components of the gas mixture 907.

[0235] In some embodiments, one or more gas sensors may be located near sampling port 912, and these gas sensors may communicate with control device 918 via wired or wireless connection. In some embodiments, one or more gas sensors are located in gas monitoring device 1100. Sample gas flow may flow from sampling port 912 through sampling loop 914 to gas monitoring device 1100. Gas monitoring device 1100 may communicate with control device 918 via wired or wireless connection. Sensor signals indicating the concentration of one or more components (e.g., NO, NO2, and O2) may be transmitted from gas sensors or from gas monitoring device 1100 to control device 918. Control device 918 may generate control signals in response to received sensor signals, and may send control signals to one or more components of the system to adjust the concentration of one or more components of gas mixture 907. For example, control device 918 may send control signals to energy source 114 to adjust NO concentration or to flow controller 916 to adjust the concentrations of NO, NO2, and O2 in gas mixture 907.

[0236] The gas monitoring device 1100 may include various features. For example, the gas monitoring device 1100 may include an alarm device configured to provide one or more alarms (such as audible or visual alarms) when the concentration of one or more measured gases in the gas mixture 907 exceeds a predetermined threshold (e.g., 25 ppm for NO and 5 ppm for NO2). The gas monitoring device 1100 may include a display to show the alarm and / or the measured concentration values. Because the gas mixture 907 can pass through the humidifier 908, the sample gas stream from port 912 may have high humidity. Reducing or removing moisture from the sample gas stream of the gas mixture 907 can improve the accuracy of one or more gas sensors of the gas monitoring device 1100.

[0237] In some embodiments, the gas monitoring device 1100 includes a moisture collector 1000 configured to reduce or remove moisture from a sample gas stream of the gas mixture 907. Figure 10A This is a perspective view of a moisture collector 1000 according to some embodiments of the present disclosure. Figure 10BThis is a partial perspective view of the water collector 1000. Figure 10C This is another partial perspective view of the water collector 1000. (See image.) Figures 10A-10C As shown, in some embodiments, the moisture collector 1000 includes one or more inlets (e.g., inlet 1008) and one or more outlets (e.g., first outlet 1010 and second outlet 1012). A gas flow 1009 (e.g., a sample gas flow from port 912) may enter the moisture collector 1000 via one or more inlets, and the gas flow may exit the moisture collector 1000 via one or more outlets. For example, as Figure 10A As shown, the gas flow 1009 can enter the moisture collector 1000 through the inlet 1008, and the gas flow can be divided into a first gas flow 1014 and a second gas flow 1016 that exit the moisture collector 1000 through the first outlet 1010 and the second outlet 1012, respectively.

[0238] In some embodiments, the moisture collector 1000 includes a cup 1002, a cover 1004, and a moisture filter 1006. In some embodiments, the moisture filter 1006 is disposed between the cup 1002 and the cover 1004. A gas flow 1009 may flow from an inlet 1008 through the moisture filter 1006 and exit from an outlet 1010 and / or an outlet 1012. The moisture filter 1006 may be permeable to gas but not to moisture (such as water droplets or water vapor). For example, the moisture filter 1006 may include a porous material with pores configured to allow gas molecules to pass through but not larger particles (such as water molecules or solid particles). In some embodiments, the moisture filter 1006 includes a porous membrane. In some embodiments, the porous membrane is a gas-permeable membrane. In some embodiments, the porous membrane is a hydrophobic membrane.

[0239] In some embodiments, the moisture collector 1000 includes one or more flow paths configured to allow a gas flow from an inlet to an outlet. In some embodiments, the moisture collector 1000 includes a first chamber 1018 and a second chamber 1020 defining flow paths. The first chamber 1018 may be located downstream of and in fluid communication with an inlet 1008. The second chamber 1020 may be located downstream of and in fluid communication with the first chamber 1018, and upstream of and in fluid communication with an outlet 1010. A moisture filter 1006 may be located between the first chamber 1018 and the second chamber 1020. A gas flow 1009 may flow from the first chamber 1018 through the moisture filter 1006 to the second chamber 1020, and this gas flow may be converted into a first gas flow 1014 with a moisture level lower than that of the gas flow 1009.

[0240] For example, moisture blocked by the moisture filter 1006 may accumulate in the first chamber 1018 and on the moisture filter 1006. The accumulated moisture may form liquid droplets. These droplets may accumulate on the side of the moisture filter 1006 facing the gas flow 1009 or the first chamber 1018, may be collected in the first chamber 1018, and may flow through the opening 1022 of the first chamber 1018 to the cup 1002. The liquid accumulated on the moisture filter 1006 can reduce the flow rate of the gas flow 1009 through that moisture filter, such as the liquid accumulated on the side of the moisture filter 1006 facing the first chamber 1018. This liquid accumulation may clog the pores of the gas-permeable membrane of the moisture filter 1006 and reduce the gas flow rate of the moisture collector 1000. In some embodiments, the moisture filter 1006 is arranged at an angle so that liquid accumulates towards the edge of the moisture filter 1006 due to gravity.

[0241] In some embodiments, the moisture collector 1000 includes one or more additional flow paths to increase the throughput of the gas flow through the moisture collector 1000. For example, the moisture filter 1006 may include a third chamber 1024 and a fourth chamber 1026. The third chamber 1024 may be configured in fluid communication with the cup 1002, for example, via an opening. The fourth chamber 1026 may be located downstream of and in fluid communication with the third chamber 1024, and located upstream of and in fluid communication with the outlet 1012. The moisture filter 1006 may be located between the third chamber 1024 and the fourth chamber 1026. Figure 10A As shown, the second gas flow 1016 can be directed from the moisture filter 1006 to the cup 1002, and this second gas flow can flow from the cup 1002 to the third chamber 1024, through the moisture filter 1006, and into the fourth chamber 1026. The second gas flow 1016 can exit the moisture collector 1000 via the outlet 1012. The second gas flow 1016 can remove liquid (such as water) accumulated on the moisture filter 1006, thereby increasing the throughput of gas flowing through the moisture filter 1006.

[0242] In some embodiments, such as Figure 11A-11D As shown, one or more outlets of the moisture collector 1000 are in fluid communication with the gas sensing circuit of the gas monitoring device 1100. For example, outlets 1010 and 1012 may be in fluid communication with the gas sensing circuit. One or more gas flows from the moisture collector 1000 can be used to measure gas concentration via the gas sensing circuit. In some embodiments, a first gas flow 1014 from the moisture collector 1000 is used by the gas sensing circuit to measure gas concentration.

[0243] The gas sensing loop of the gas monitoring device 1100 may include various components and features for measuring gas concentration and / or improving measurement accuracy. In some embodiments, the gas monitoring device 1100 includes a sensing module 1102. The sensing module 1102 may include one or more gas sensors, such as NO2 sensor 1102a, NO sensor 1102b, and O2 sensor 1102c. One or more gas sensors may be disposed in one or more chambers configured to receive at least a portion of a gas flow (e.g., a first gas flow 1014) circulating in the gas sensing loop. For example, as... Figure 11A-11D As shown, a gas sensor can be disposed in a chamber to measure the gas concentration flowing through it. The gas monitoring device 1100 may include a computer-readable storage device and / or a processor (not shown) that communicates wired or wirelessly with the sensor to receive and process sensing signals received from the sensor. The gas monitoring device 1100 may include a transmitter loop (not shown) that communicates wired or wirelessly with the processor, computer-readable storage device, and / or gas sensor to transmit the sensing signals or readings to a controller, such as a control device 918 or an electronic device (e.g., a tablet, computer, or smartphone). The gas sensor readings may be obtained by the gas sensor or processor based on the sensing signals.

[0244] In some embodiments, the gas sensing circuit of the gas monitoring device 1100 includes a pump 1104. The pump 1104 is configured to generate or drive one or more gas flows in the gas sensing circuit. In some embodiments, the gas sensing circuit includes one or more valves configured to guide one or more gas flows in the gas sensing circuit. For example, the gas sensing circuit may include at least one one-way valve 1106, such as a ball check valve. The one-way valve 1106 can be positioned in any suitable location to prevent backflow. For example, the pump 1104 may be positioned downstream of the gas sensing circuit to allow gas flows from the pump outlet to be released into the environment. The one-way valve 1106 may be positioned downstream of the pump 1104 to prevent ambient air from flowing back into the gas sensing circuit.

[0245] In some embodiments, the gas monitoring device 1100 includes one or more switching valves configured to change the direction or flow path of gas flow in a gas sensing circuit. For example, the gas monitoring device 1100 may include a first switching valve 1110 and a second switching valve 1112. The switching valve may have one or more positions (e.g., a first position and a second position) for selecting the gas flow path or flow direction in the gas sensing circuit. The position of the switching valve can be selected manually or automatically using a user interface. The user interface may be, for example, a graphical user interface or a control panel, such as a switch or button.

[0246] In some embodiments, one or more switching valves may be located in the control module 1114. For example... Figure 11A-11D As shown, the control module 1114 may include one or more connection ports, such as connection ports 1116A-1116G. Switching valves may be fluidly connected to one or more connection ports. This configuration can improve the assemblability and / or maintainability of the gas monitoring device 1100. For example, a first switching valve 1110 may have a first position for fluid connection to connection ports 1116A and 1116C, and the first switching valve may have a second position for fluid connection to connection ports 1116A and 1116D. For example, a second switching valve 1112 may have a first position for fluid connection to connection ports 1116E and 1116G, and the second switching valve may have a second position for fluid connection to connection ports 1116F and 1116G. In some embodiments, the selected connection ports may be fluidly connected to form one or more flow paths. For example, connection ports 1116B and 1116C may be fluidly connected. The various uses of the switching valves in one or more operating processes of the gas monitoring device 1100 are further described below.

[0247] In some embodiments, the gas monitoring device 1100 includes one or more pressure sensors. In some embodiments, the gas monitoring device 1100 includes at least one absolute pressure sensor 1118. In some embodiments, the gas monitoring device 1100 includes at least one differential pressure sensor 1120. The differential pressure sensor can be used to measure the flow rate of a gas flow in a gas sensing loop. For example, the flow rate of the gas flow can be calculated based on the differential pressure measured by the differential pressure sensor 1120 and Bernoulli's equation.

[0248] In some embodiments, the gas sensing loop of the gas monitoring device 1100 includes one or more flow regulators, such as a first flow regulator 1122 and a second flow regulator 1124. The flow regulator may be a flow controller, a flow limiter, or a flow restrictor. The flow regulator may be configured to control the flow rate of a gas stream flowing through it. For example, the flow regulator may be configured to limit the flow rate of a gas stream in a flow path to a specific range or a specific value. In some embodiments, the first flow regulator 1122 is configured to regulate a first gas stream 1014 from the moisture collector 1000. In some embodiments, the second flow regulator 1124 is configured to regulate a second gas stream 1016 from the moisture collector 1000. In some embodiments, a differential pressure sensor 1120 is configured to measure the differential pressure across the flow regulator 1122.

[0249] In some embodiments, the gas monitoring device 1100 includes one or more filters. The filters can be positioned at any suitable location in the gas sensing circuit to reduce or remove one or more impurities, such as moisture and solid matter, from the gas flow. Such filters can further reduce or remove moisture from the gas sensing module to improve the measurement accuracy of the gas sensor. Additionally or alternatively, such filters can reduce or prevent solid matter from entering the valve, thereby increasing the lifespan of the gas monitoring device 1100.

[0250] In some embodiments, filter 1128 is disposed upstream of gas sensing module 1102. Filter 1128 may include a moisture filter configured to reduce or remove moisture, such as water, from the gas and / or liquid phases. Filter 1128 may include a membrane filter, such as a Nafion membrane filter. TM Membrane filter. The gas sensing circuit of the gas monitoring device 1100 may include one or more gas inlets (e.g., a first gas inlet 1127a and a second gas inlet 1127b), which are configured to receive airflow from the environment or a gas supply (e.g., a compressed air supply). A filter 1126 may be located downstream of the gas inlets to reduce or remove moisture and / or dust from the gasflow received by the gas inlets.

[0251] In some embodiments, the gas sensing circuit includes one or more NO... x Absorber 1108. NO x Absorber 1108 can be configured to absorb one or more nitrogen oxides, such as NO2 and NO. In some embodiments, NO x An absorber 1108 is positioned upstream of the gas inlet to remove or reduce one or more nitrogen oxides, such as NO2 and NO, in the airflow entering the gas sensing circuit via the gas inlet. The gas sensing circuit may include one or more gas outlets (e.g., gas outlet 1129) configured to output a gas flow (e.g., a second gas flow 1016 or a first gas flow 1014) to the environment. In some embodiments, NO x The absorber 1108 is positioned downstream of the gas outlet to remove or reduce one or more nitrogen oxides, such as NO2 and NO, before releasing the gas stream into the environment.

[0252] NO x Absorber 1108 may include components configured to absorb one or more nitrogen oxides (NOx). x One or more absorbent materials (such as NO and NO2). x The absorbent material in absorber 1108 can be similar to the absorbent material in exhaust gas treatment device 700. xThe absorber 1108 may have a structure similar to that of the exhaust gas treatment device 700. For example, NO x The absorber 1108 may include a tortuous flow path, at least a portion of which is filled with one or more absorbent materials.

[0253] Various components of the gas monitoring device 1100 can be used in one or more operating processes, such as initialization, calibration, sampling, and cleaning. These processes can be automatically controlled by a processor and / or manually controlled by a user via a user interface (such as a control panel or graphical user interface). Examples of the various processes performed by the gas monitoring device 1100 are described below.

[0254] In some embodiments, the gas monitoring device 1100 is configured to perform an initialization process. Figure 11A This is a schematic diagram illustrating the initialization process of a gas monitoring device 1000 according to some embodiments of the present disclosure. An initialization process may be performed to reduce or remove moisture in the gas sensing circuit and / or purge previously present gases from the gas sensing circuit. For example, during the initialization process, ambient air may be introduced into at least a portion of the gas sensing circuit and allowed to pass through at least a portion of the gas sensing circuit to dry and / or purge one or more flow paths of the sensing module 1102 and / or the gas sensing circuit.

[0255] In some embodiments, such as Figure 11A As shown, during the initialization process, one or more switching valves can be switched to appropriate positions to fluidly connect selected connection ports, thereby guiding one or more gas flows in the gas sensing circuit. For example, the first switching valve 1110 can be switched to a second position to fluidly connect connection ports 1116A and 1116D. The second switching valve 1112 can be switched to its second position to fluidly connect connection ports 1116F and 1116G. Figure 11A As indicated by the arrows, during the initialization process, for example, pump 1104 can generate an airflow through the gas sensing loop (i.e., from gas inlet 1127a, through connection ports 1116D and 1116A, sensing module 1102, filter 1128, connection ports 1116G and 1116F, to outlet 1010). During the initialization process, the airflow can also flow through one or more of flow controller 1122, filter 1126, flow controller 1124, and check valve 1106. The airflow can flow through NO before leaving the sensing loop via gas outlet 1129. x Absorber 1108.

[0256] During the initialization process, such as Figure 11AAs shown, pump 1104 can drive airflow to outlet 1010, through cup 1002, outlet 1012, connection ports 1116B and 1116C, and to gas outlet 1129. The initialization process can be performed for any suitable duration, such as less than about 1 minute, less than about 30 seconds, less than about 10 seconds, or less than about 1 second.

[0257] During the initialization process, it can be determined whether the various components of the gas monitoring device 1100 can operate under normal conditions. Additionally or alternatively, the gas monitoring device 1100 can generate one or more alarms to indicate one or more abnormal conditions in the gas sensing circuit. For example, a switching valve can be switched to different positions to determine whether the valve can operate under normal conditions. Pump 1104 can be set to a certain flow rate, and the flow rate of the gas stream generated by pump 1104 can be measured to determine whether pump 1104 can operate under normal conditions. When there is no gas flow in the gas sensing circuit, the normal reading of the absolute pressure sensor 1118 will not exceed a predetermined value, such as any value from approximately 600 mbar to approximately 1250 mbar, and the normal flow rate calculated based on the reading of the differential pressure sensor 1120 can not exceed the predetermined flow rate range set by the pump, such as from approximately 50 ml / min to approximately 1000 ml / min.

[0258] In some embodiments, the gas monitoring device 1100 is configured to perform a calibration process to calibrate one or more gas sensors in the sensing module 1102. The calibration process can be performed regularly, such as periodically, on demand, or before the gas mixture 907 is delivered to the patient. The sensors can be calibrated using air (such as ambient air or compressed air) or a standard gas with a known concentration of its gaseous components. Figure 11B This is a schematic diagram of the calibration process of a gas monitoring device 1100 according to some embodiments of the present disclosure. In some embodiments, such as Figure 11B As shown, ambient air is used during the calibration process. For example, the first switching valve 1110 can be switched to its first position to fluidly connect connection ports 1116B and 1116C. The second switching valve 1112 can be switched to its first position to fluidly connect connection ports 1116E and 1116G. Pump 1104 can generate an airflow from gas inlet 1127b through connection ports 1116E and 1116G, filter 1128, sensing module 1102, connection ports 1116A and 1116C to gas outlet 1129. xAbsorber 1108 may be positioned downstream of gas inlet 1127b to remove or reduce NO2 and NO before the airflow passes through sensing module 1102. The airflow may also pass through one or more of flow controller 1122, filter 1126, and check valve 1106.

[0259] During the calibration process, pump 1114 can also drive gas flow 1016 from outlet 1012 through connection ports 1116B and 1116C to gas outlet 1129. Gas flow 1016 can also flow through filter 1126, flow regulator 1124, check valve 1106, and NO... x One or more of the absorbers 1108.

[0260] In some embodiments, a calibration process is performed to adjust the calibration curve of at least one sensor of the sensing module 1102, such as by adjusting the calibration curve with an offset value. The calibration process may include zero-point calibration and / or range calibration. For example, in zero-point calibration, airflow from the environment passes through NO... x The absorber 1108 can be pre-programmed to have approximately 21% O2, approximately 0% or 0 ppm NO, and approximately 0% or 0 ppm NO2. The sensors in the sensing module can assume that the airflow readings correspond to these predetermined concentrations and their calibration curves can be adjusted with offset values.

[0261] In some embodiments, during range calibration, one or more standard gases, such as O2, NO, and / or NO2 concentrations known, can be used during the calibration process. For example... Figure 11C As shown, the first switching valve 1110 can be switched to its first position to fluidly connect to connection ports 1116A and 1116C. The second switching valve 1112 can be switched to its second position to fluidly connect to connection ports 1116F and 1116G. Pump 1104 can drive standard gas from outlet 1010 through connection ports 1116F, 1116G, filter 1128, sensing module 1102, 1116A, and 1116C and flow to gas outlet 1129. Before releasing the standard gas flow via gas outlet 1129, the standard gas flow can also pass through flow controller 1122, check valve 1106, and NO. x One or more absorbers 1108. The sensors of the sensing module can assume that the readings of the standard gas flow correspond to the known concentrations of the standard gas and their calibration curves can be adjusted with offset values.

[0262] In some embodiments, the gas monitoring device 1100 is configured to perform a sampling process to measure the concentration of one or more gas components in a sample gas stream. Figure 11CThis is a schematic diagram of the sampling process of a gas monitoring device 1100 according to some embodiments of the present disclosure. The sampling process can be performed on demand, or it can be performed continuously or intermittently while delivering a gas mixture 907 to a patient 910. In some embodiments, during sampling, the gas sensing circuit may receive a first gas flow 1014 from the outlet 1010 of the moisture collector 1000 and / or a second gas flow 1016 from the outlet 1012 of the moisture collector 1000. A first flow regulator 1122 can regulate the flow rate of the first gas flow 1014 to a first flow rate. A second flow regulator 1124 can regulate the flow rate of the second gas flow 1016 to a second flow rate. The first and second flow rates can be predetermined and adjusted based on the settings of the pump 1104 and / or the settings of the flow regulators 1122 and 1124. The first and second flow rates can be added together to become the flow rate of the pump 1104. For example, the flow rate of pump 1104 can be in the range of about 50 mL / min to about 1000 mL / min, the first flow rate of the first gas flow 1014 can be in the range of about 40 mL / min to about 800 mL / min, and the second flow rate of the second gas flow 1016 can be in the range of about 10 mL / min to about 200 mL / min.

[0263] In some embodiments, the concentration in the first gas stream 1014 is measured during sampling. For example... Figure 11C As shown, the first switching valve 1110 can be switched to its first position to fluidly connect to connection ports 1116A and 1116C. The second switching valve 1112 can be switched to its second position to fluidly connect to connection ports 1116F and 1116G. Pump 1104 can drive a first gas flow 1014 from outlet 1010 through connection ports 1116F, 1116G, filter 1128, sensing module 1102, 1116A, and 1116C to gas outlet 1129. Before releasing the first gas flow 1014 via gas outlet 1129, the first gas flow can also pass through flow regulator 1122, check valve 1106, and NO... x One or more absorbers 1108. Pump 1104 can also drive a second gas flow 1016 from outlet 1012 through connection ports 1116B and 1116C to gas outlet 1129. Before being released via gas outlet 1129, the second gas flow 1016 can also pass through flow regulator 1124, check valve 1106, and NO. x One or more of the absorbers 1108.

[0264] In some embodiments, one or more gas sensors of the sensing module 1102 are configured to identify and measure the concentration of one or more gaseous components (such as NO2, NO, and O2) in the first gas flow 1014 as it passes through the gas sensing module 1102. Readings from these sensors can be transmitted via wired or wireless communication to a processor and / or computer-readable storage medium (not shown) of the gas monitoring device 1100 for further processing and / or transmission to one or more other devices.

[0265] When the first gas flow 1014 passes through the sensor at a predetermined flow rate or within a predetermined flow range, the accuracy of one or more sensors in the sensing module 1102 can be improved. In some embodiments, the flow rate of the first gas flow 1014 is controlled by a flow controller 1122, and a differential pressure sensor 1120 is used to measure the flow rate of the first gas flow 1014 passing through the flow controller 1122. The predetermined flow rate or flow range can be any suitable value or range based on the sensor type. For example, one or more sensors can be electrochemical sensors, and the predetermined flow rate range can be from approximately 50 ml / min to approximately 450 ml / min, such as from approximately 220 ml / min to approximately 240 ml / min. A pump 1104 can be used to adjust the flow rate of the first gas flow 1014 through the sensing module to the predetermined value or range.

[0266] In some embodiments, the gas monitoring device 1100 is configured to perform a cleaning process to reduce or remove liquid accumulated on the moisture filter 1006 of the moisture collector 1000 and / or in the gas sensing circuit. Figure 11D This is a schematic diagram of the cleaning process of a gas monitoring device 1100 according to some embodiments of the present disclosure. Figure 11D As shown, the first switching valve 1110 can be switched to its second position to disconnect connection ports 1116A and 1116C, thereby disconnecting the first gas flow 1014. The second switching valve 1112 can be switched to its first position to fluidly connect connection ports 1116E and 1116G. Pump 1104 can drive the second gas flow 1016 from outlet 1012 through connection ports 1116B and 1116C and to gas outlet 1129. Before releasing the second gas flow 1016 via gas outlet 1129, the second gas flow can also pass through filter 1126, flow regulator 1124, check valve 1106, and NO. x One or more of the absorbers 1108.

[0267] During the cleaning process, disconnecting the first gas flow 1014 allows the flow rate of the second gas flow 1016 to increase. For example... Figure 10AAs shown, before leaving outlet 1012, the second gas flow 1016 can flow from the first chamber 1018 to the cup 1002 and back to the moisture filter 1006, for example, on the side of the moisture filter 1006 facing the gas flow 1009 or the side facing the first chamber 1018, where liquid can accumulate. Increasing the flow rate of the second gas flow 1016 can increase the drying or removal of liquid accumulated on the moisture filter 1006.

[0268] The gas monitoring device 1100 can perform a cleaning process based on demand and / or in the event of one or more abnormal conditions. The cleaning process can be performed for any suitable duration, such as less than about 2 minutes, less than about 1 minute, less than about 30 seconds, or less than about 10 seconds. The cleaning process can be started automatically or manually. For example, when liquid clogs at least a portion of the moisture filter 1006 and / or the flow path in the gas sensing circuit, the processor of the gas monitoring device 1100 can initiate the cleaning process in response to one or more abnormal readings from the absolute pressure sensor 1118 and / or the differential pressure sensor 1120. For example, during a sampling process, the normal absolute pressure measured by the pressure sensor 1118 can be in the range of about 0.5 bar to about 1.25 bar. Absolute pressures outside this range may indicate that the moisture filter 1006 and / or the gas sensing circuit are clogged with liquid. The normal flow rate, calculated based on the differential pressure measured by pressure sensor 1120, can range from approximately 20 ml / min to approximately 275 ml / min, for example, from approximately 20 ml / min to approximately 50 ml / min, from approximately 50 ml / min to approximately 100 ml / min, from approximately 100 ml / min to approximately 150 ml / min, from approximately 150 ml / min to approximately 200 ml / min, from approximately 200 ml / min to approximately 250 ml / min, or from approximately 250 ml / min to approximately 275 ml / min. Flow rates below this range may indicate that the moisture filter 1006 and / or the gas sensing circuit are clogged with liquid.

[0269] As described herein, system 10 can be modularized, allowing for easy replacement, maintenance, or repair of one or more of its components, such as reaction chamber 102, reaction medium 112, one or more electrodes (e.g., first electrode 116, second electrode 118), filtration system 500 or its filters, pressure vessel 600, exhaust gas treatment device 700, gas converter 800, and flow control device, without substantially requiring disassembly of system 10. Therefore, maintenance costs of system 10 can be reduced, and the operational life of system 10 can be extended.

[0270] In some embodiments, system 10 may include a user interface that communicates with a control loop. The user interface may include one or more controllers for receiving instructions from the user to adjust system parameters, such as the number of stages, the number of operating cycles in each stage, and the concentration and / or flow rate of NO in a stage or operating cycle. The control loop may send control signals to various components to adjust these system parameters, such as energy source 114, carrier gas source 200, and flow controllers or control devices.

[0271] System 10 or one or more of its components, such as the NO generating device 100 described herein, can be used in various methods for generating and / or delivering NO. For example, system 10 or NO generating device 100 can be used to generate NO on demand. In some embodiments, system 10 or NO generating device 100 can be used to provide a stable supply of NO at a predetermined concentration during a ramp cycle. A ramp cycle can refer to a transition period in which the NO concentration of the product gas changes from an initial concentration to a predetermined steady-state concentration. For example, during a ramp cycle, the NO concentration of the product gas increases from an initial concentration (e.g., zero) to a predetermined steady-state concentration. System 10 or NO generating device 100 can be used to provide a stable supply of NO in one or more phases or in one or more operating cycles. System 10 can be used to reduce or minimize potential air pollution and / or exposure to toxic gases (e.g., nitrogen dioxide) during NO generation or delivery. System 10 can be used to deliver NO using an alternative processing gas (e.g., oxygen or air) supplied by a breathing apparatus (e.g., a ventilator). System 10 can be used to monitor the concentration of one or more components in a gas mixture to be delivered to or inhaled by a patient.

[0272] As described herein, the steps of the disclosed method may be modified in any way, including reordering, inserting, and / or deleting steps. Unless otherwise stated, one or more steps of the disclosed method may be performed simultaneously or in any suitable temporal order.

[0273] Figure 12 This is a flowchart illustrating a NO generation method 1200 according to some embodiments of the present disclosure. In some embodiments, such as Figure 12 As shown, method 1200 includes steps 1202-1210. In some embodiments, step 1202 includes applying a voltage or current to one or more of a plurality of electrodes disposed in a reaction medium via an energy source to generate NO. The plurality of electrodes may include cathodes. In some embodiments, NO is generated at or near one or more surfaces of the plurality of electrodes. The reaction medium may be contained in a reaction chamber of a NO generating apparatus. In some embodiments, the reaction chamber includes a gas region and a liquid region, and the reaction medium is disposed in the liquid region.

[0274] In some embodiments, in step 1202, the voltage or current applied to the plurality of electrodes may be predetermined and / or adjusted based on one or more conditions (such as the desired NO concentration in the output product gas). In some embodiments, the predetermined voltage ranges from about 1.4V to about 5.0V. In some embodiments, the predetermined current ranges from about 0mA to about 300mA. The rate of NO generation may increase with increasing voltage or current applied to the plurality of electrodes. In some cases, NO may be generated when a current of about 0mA is applied to the plurality of electrodes. In some embodiments, step 1202 includes terminating the voltage or current applied to the plurality of electrodes.

[0275] In some embodiments, step 1202 includes applying an excitation voltage or excitation current to a plurality of electrodes during an excitation cycle before applying a predetermined voltage or predetermined current. The excitation cycle can range from about 0.5 minutes to about 5 minutes, such as from about 0.5 minutes to about 1 minute, from about 1 minute to about 2 minutes, from about 2 minutes to about 3 minutes, from about 3 minutes to about 4 minutes, from about 4 minutes to about 5 minutes, or combinations thereof. In some embodiments, the excitation voltage is about 2 to about 8 times the predetermined voltage. In some embodiments, the excitation current is about 2 to about 8 times the predetermined current.

[0276] In some embodiments, step 1202 includes switching the polarity of the two electrodes (e.g., cathode and anode). For example, step 1202 may include reversing the polarity of an energy source, such as reversing the polarity of a DC power supply or using an AC power supply. The polarity of the two electrodes may be switched based on demand or according to a predetermined schedule. For example, the polarity of the two electrodes may be switched periodically, such as from approximately every 10 minutes to approximately every 10 hours.

[0277] In some embodiments, method 1200 includes step 1204. In some embodiments, step 1204 includes receiving a carrier gas from an NO generating device through an inlet circuit of the NO generating device. The inlet circuit may be in fluid communication with at least one sprayer disposed in the reaction medium. The at least one sprayer may be located near one or more of a plurality of electrodes. In some embodiments, carrier gas is received from a carrier gas source. In some embodiments, the carrier gas includes nitrogen. In some embodiments, step 1204 includes generating carrier gas from compressed air from the carrier gas source. For example, a nitrogen generating device may be used to generate carrier gas from compressed air.

[0278] In some embodiments, step 1204 includes controlling the flow rate of the carrier gas received through the inlet loop by a flow control device. In some embodiments, step 1204 includes receiving the carrier gas at a certain flow rate, which ranges from about 50 mL / min to about 12 L / min, such as from about 0.5 L / min to about 1 L / min, from about 1 L / min to about 3 L / min, from about 3 L / min to about 5 L / min, from about 5 L / min to about 8 L / min, from about 8 L / min to about 10 L / min, from about 10 L / min to about 12 L / min, or combinations thereof.

[0279] In some embodiments, step 1204 includes using a carrier gas purging system 10. For example, the carrier gas may pass through some or all of the gas flow regions or paths of the system, such as the gas region of the reaction chamber, inlet and outlet loops, circulation loops, and pressure vessels. Using the carrier gas purging system 10 can reduce the oxidation of NO generated in the product gas into toxic nitrite oxides (such as NO2). Purging the system 10 can improve the lifespan of the gas converter, which is configured to reduce or remove NO2.

[0280] In some embodiments, method 1200 includes step 1206. In some embodiments, step 1206 includes sweeping the surface of one or more of a plurality of electrodes with a carrier gas. Sweeping the electrode surfaces can sweep, purge, and / or entrain NO generated at or near the electrode surfaces from the reaction medium. This may generate a product gas, which may include the generated NO and the carrier gas. In some embodiments, at least a portion of the product gas is received and / or accumulated in the gas region of the reaction chamber of the NO generation apparatus.

[0281] In some embodiments, step 1206 includes generating bubbles of carrier gas to sweep across the surface of one or more of the plurality of electrodes. For example, step 1206 may include receiving carrier gas via a sprayer, and this step may include emitting bubbles of carrier gas in the reaction medium via the sprayer to sweep across the surface of one or more of the plurality of electrodes. The sprayer may be in fluid communication with an inlet loop and is disposed in the reaction medium adjacent to one or more of the plurality of electrodes. The bubbles emitted by the sprayer may propagate along a bubble path that may extend along the surface of at least one electrode.

[0282] In some embodiments, method 1200 includes step 1208. In some embodiments, step 1208 includes circulating a first fluid flow relative to the reaction chamber using a first circulation loop. In some embodiments, step 1208 includes generating a first fluid flow from the inlet to the outlet of the first circulation loop using a gas pump. In some embodiments, the first fluid flow includes the product gas flow generated in step 1206. In some embodiments, step 1208 includes filtering the recirculated fluid flow using one or more filters disposed upstream of the gas pump. The one or more filters may reduce or remove liquid and / or solid substances from the recirculated fluid flow before it enters the gas pump.

[0283] In some embodiments, step 1208 may include circulating a first fluid flow at a certain flow rate, the certain flow rate ranging from about 0.5 L / min to about 5.0 L / min, such as from about 0.5 L / min to about 1.0 L / min, from about 1.0 L / min to about 1.5 L / min, from about 1.5 L / min to about 2.0 L / min, from about 2.0 L / min to about 2.5 L / min, from about 2.5 L / min to about 3.0 L / min, from about 3.0 L / min to about 3.5 L / min, from about 3.5 L / min to about 4.0 L / min, from about 4.0 L / min to about 4.5 L / min, from about 4.5 L / min to about 5.0 L / min, or combinations thereof.

[0284] In some embodiments, method 1200 includes step 1210. In some embodiments, step 1210 includes conveying a product gas containing NO from the reaction chamber through an outlet circuit. In some embodiments, the outlet circuit is in fluid communication with a gas region of the reaction chamber. In some embodiments, the NO concentration of the product gas conveyed from the reaction chamber can reach a steady state within a ramp cycle. For example, the ramp cycle can range from approximately 2 minutes to approximately 10 minutes.

[0285] In some embodiments, method 1200 may include one or more steps selected from steps 1212-1222 below.

[0286] In some embodiments, method 1200 includes step 1212. In some embodiments, step 1212 includes measuring the concentration of NO in the product gas using an NO concentration sensor. In some embodiments, the NO concentration sensor may be configured to contact the product gas in the gas region to measure the NO concentration in the gas region. In some embodiments, the NO concentration sensor may be located in, near, or downstream of the outlet circuit of the reaction chamber to detect the NO concentration of the product gas leaving the reaction chamber. For example, the NO sensor may be located at the opening of the outlet circuit, inside the conduit of the outlet circuit, or downstream of a filter located downstream of the outlet circuit.

[0287] In some embodiments, method 1200 includes step 1214. Step 1214 may reduce or remove NO dissolved in the reaction medium after NO is generated during a stage or operating cycle. Step 1214 may include separating at least some of the dissolved NO from the reaction medium. Step 1214 may further include treating the separated NO, for example, using an exhaust gas treatment device.

[0288] In some embodiments, step 1214 includes circulating a second fluid flow relative to the reaction chamber using a second circulation loop. In some embodiments, the second fluid flow in the second circulation loop comprises a liquid flow. In some embodiments, the second fluid flow in the second circulation loop comprises a gas flow. In some embodiments, step 1214 is performed before, during, and / or after NO is generated using the reaction medium in step 1202. For example, step 1214 may be performed after the voltage or current applied to the electrode is terminated after NO is generated within a stage or operating cycle. Step 1214 may be performed before voltage or current is applied to the electrode to generate NO for the next stage or operating cycle.

[0289] In some embodiments, step 1214 includes configuring and / or operating the second circulation loop to operate in an operating mode. In the operating mode, the second fluid flow may include a reaction medium flow. In some embodiments, operating the second circulation loop in the operating mode includes using a pump to circulate the second fluid flow from a first port of the second circulation loop through the liquid-gas separation device and out of a second port of the second circulation loop. The first port may be in fluid communication with the liquid region of the reaction chamber, while the second port may be in fluid communication with the gas region of the reaction chamber.

[0290] In operating mode, the second fluid flow can circulate at any suitable flow rate, such as a range from approximately 0.1 L / min to approximately 0.5 L / min, from approximately 0.5 L / min to approximately 1.0 L / min, from approximately 1.0 L / min to approximately 3.0 L / min, from approximately 3.0 L / min to approximately 5.0 L / min, from approximately 5.0 L / min to approximately 8.0 L / min, or combinations thereof. The second circulation loop can operate in operating mode for any suitable time, such as less than approximately 0.5 minutes, less than approximately 1 minute, less than approximately 2 minutes, less than approximately 5 minutes, less than approximately 10 minutes, or less than approximately 20 minutes.

[0291] In some embodiments, operating the second circulation loop in operating mode includes separating NO from the reaction medium as the second fluid flow passes through the liquid-gas separator. In some embodiments, operating the second circulation loop in operating mode includes passing a swept gas through the liquid-gas separator to entrain the NO separated from the second fluid flow as a mixed gas from the liquid-gas separator. In some embodiments, operating the second circulation loop in operating mode includes transporting the mixed gas to an exhaust gas treatment device before releasing the mixed gas into the environment.

[0292] In some embodiments, step 1214 includes configuring and / or operating the second circulation loop in a clean mode. The clean mode can be operated after the operating mode. In the clean mode, the second fluid flow may include a gas flow. In some embodiments, operating the second circulation loop in the clean mode includes using a pump to circulate the second fluid flow from a second port of the second circulation loop through the liquid-gas separator and out from a first port of the second circulation loop. In some embodiments, operating the second circulation loop in the clean mode includes transporting residual reaction medium in the liquid-gas separator back to the reaction chamber. The clean mode may prepare the liquid-gas separator for the next operating mode, for example, by drying the separation membrane of the liquid-gas separator.

[0293] In cleaning mode, the second fluid flow can circulate at any suitable flow rate, such as a range from approximately 0.25 L / min to approximately 0.5 L / min, from approximately 0.5 L / min to approximately 1.0 L / min, from approximately 1.0 L / min to approximately 3.0 L / min, from approximately 3.0 L / min to approximately 5.0 L / min, or a combination thereof. The second circulation loop can operate in cleaning mode for any suitable time, such as less than approximately 0.5 minutes, less than approximately 1 minute, less than approximately 2 minutes, or less than approximately 5 minutes.

[0294] In some embodiments, step 1214 may include configuring the switching valve to a first position to allow the second circulation loop to operate in an operating mode, and the step may include configuring the switching valve to a second position to allow the second circulation loop to operate in a cleaning mode.

[0295] In some embodiments, step 1214 includes purging the reaction chamber (e.g., the gas region of the reaction chamber) with a carrier gas. The carrier gas may accumulate in the gas region of the reaction chamber, and the carrier gas may circulate in a second circulation loop in a cleaning mode.

[0296] In some embodiments, method 1200 includes step 1216. In some embodiments, step 1216 includes passing a product gas from the reaction chamber through a filtration system. Step 1216 may include reducing or removing one or more impurities, such as solid matter (e.g., salt aerosols) and moisture, from the product gas through the filtration system. The filtration system may include one or more filtration devices or filters.

[0297] In some embodiments, method 1200 includes step 1218. In some embodiments, step 1218 includes delivering a product gas to a pressure vessel. In some embodiments, step 1218 includes receiving and storing the product gas in the pressure vessel for a pressure holding period. At the end of the pressure holding period, the pressure and / or NO concentration in the pressure vessel may be increased to a predetermined level or range. In some embodiments, the pressure vessel includes a first region and a second region. Step 1218 may include receiving the product gas through an inlet in fluid communication with the first region of the pressure vessel. Step 1218 may include storing the product gas in the first region of the pressure vessel. Step 1218 may include releasing the product gas from the pressure vessel, for example, through an outlet in fluid communication with the first region. The NO concentration in the product gas released from the pressure vessel may reach a steady state within a ramp period. A ramp period may refer to a transition period in which the NO concentration of the product gas changes from an initial concentration to a predetermined steady-state concentration. In some embodiments, step 1218 includes measuring and / or adjusting the flow rate of the product gas released from the pressure vessel using a flow control device. The flow control device may adjust the flow rate of the product gas according to instructions received from a control device.

[0298] In some embodiments, step 1218 includes receiving and storing product gas in a second region in fluid communication with the first region. Step 1218 may include storing the product gas in the second region at a pressure below or equal to a predetermined threshold. Step 1218 may include releasing the product gas stored in the second region from the second region back to the first region, and this step may further include releasing the product gas from the first region outside the pressure vessel. In some embodiments, step 1218 includes releasing gas from the pressure vessel (e.g., from the second region of the pressure vessel) via a pressure relief valve when the pressure in one or more regions of the pressure vessel exceeds a predetermined threshold. In some embodiments, step 1218 includes treating the gas released via the pressure relief valve, for example, via an exhaust gas treatment device.

[0299] In some embodiments, method 1200 includes step 1220. In some embodiments, step 1220 may include conveying a product gas through a gas converter to reduce or remove one or more toxic nitrogen oxides, such as NO2, from the product gas. In some embodiments, step 1220 includes absorbing or converting some or all of the toxic nitrogen oxides, such as NO2, through the gas converter as the product gas passes through. The toxic nitrogen oxides can be converted to NO. Step 1220 may include conveying the product gas from an inlet through a tortuous flow path to an outlet of the gas converter, and this step may include conveying the product gas through a filter material in the tortuous flow path. Step 1220 may include using the filter material to absorb some or all of the toxic nitrogen oxides in the product gas. Additionally or alternatively, step 1220 may include using the filter material to convert some or all of the toxic nitrogen oxides in the product gas to NO.

[0300] In some embodiments, method 1200 includes step 1222. In some embodiments, step 1222 includes delivering NO or a gas mixture including NO to a patient using a ventilation circuit. The gas mixture may include one or more gaseous components, such as air, oxygen, and moisture. In some embodiments, step 1222 includes delivering NO or the gas mixture to the patient through the inspiratory circuit of the ventilation circuit. In some embodiments, step 1222 includes receiving exhaled gas from the patient through the expiratory circuit of the ventilation circuit.

[0301] In some embodiments, step 1222 includes delivering NO via a gas stream (e.g., an air stream or an oxygen stream) supplied by a respiratory device (e.g., a ventilator) connected to a ventilation circuit. For example, step 1222 may include combining the gas stream (e.g., an air stream or an oxygen stream) supplied by the respiratory device (e.g., a ventilator) with a product gas stream received from the NO system to generate a gas mixture. In some embodiments, step 1222 includes adding water to the gas mixture before delivering it to the patient.

[0302] In some embodiments, step 1222 includes measuring the flow rate of a gas stream (such as an air stream or an oxygen stream) supplied from a breathing device (such as a ventilator) using a flow sensor. The flow sensor may communicate with the control device via a wired or wireless connection. Step 1222 may further include transmitting a sensing signal or reading from the flow sensor to the control device.

[0303] In some embodiments, step 1222 includes measuring the concentration of one or more components of the gas mixture to be delivered to the patient using one or more gas sensors or a gas monitoring device including one or more gas sensors. For example, step 1222 may include obtaining a sample gas stream of the gas mixture to be delivered to the patient and measuring the concentration of one or more components of that sample gas stream. The one or more gas sensors or gas monitoring devices may communicate with a control device via a wired or wireless connection. Step 1222 may include sending sensing signals or readings from one or more gas sensors or gas monitoring devices to the control device. In some embodiments, step 1222 includes providing an alarm when one or more readings from one or more gas sensors are above or below a threshold. The alarm may be any suitable form, such as an audible or visual alarm, for any suitable duration.

[0304] In some embodiments, step 1222 includes controlling the flow rate of the product gas to mix or combine it with a gas flow (such as an air flow or oxygen flow) supplied by a breathing device (such as a ventilator). For example, the control device may communicate with a flow control device configured to control the flow rate of the product gas from the NO system. The control device may send instructions to the flow control device to adjust the flow rate of the product gas. The control device may generate instructions based on one or more sensing signals or readings from one or more flow sensors and / or one or more gas sensors.

[0305] In some embodiments, step 1222 includes controlling the flow rate of air or oxygen supplied by the ventilator. For example, the control device may communicate with the ventilator via wired or wireless communication. The control device may send instructions to the ventilator to adjust the flow rate of air or oxygen.

[0306] In some embodiments, step 1222 includes operating the gas monitoring device in one or more operational processes to measure the concentration of one or more components of the gas mixture to be delivered to the patient. For example, step 1222 may include performing one or more processes of initialization, cleaning, sampling, and calibration.

[0307] The foregoing description is for illustrative purposes only. It is not exhaustive and is not limited to the precise forms or embodiments disclosed. Modifications and adaptations to the embodiments will be readily apparent in light of the description and practice of the disclosed embodiments. For example, the described implementations include hardware, but systems and methods conforming to this disclosure can be implemented in both hardware and software. Furthermore, while some components have been described as being interconnected, these components may be integrated with each other or distributed in any suitable manner.

[0308] Furthermore, while illustrative embodiments have been described herein, the scope includes any and all embodiments based on this disclosure that have equivalent elements, modifications, omissions, combinations (e.g., combinations of aspects across various embodiments), adaptations, and / or alternatives. Additionally, the steps of the disclosed methods can be modified in any way, including reordering, inserting, or deleting steps.

[0309] The features and advantages of this disclosure will be apparent from the detailed description. Furthermore, since many modifications and variations will readily arise from studying this disclosure, it is not intended to limit the disclosure to the exact configurations and operations shown and described; therefore, all suitable modifications and equivalents falling within the scope of this disclosure may be employed.

[0310] It should be understood that the above embodiments can be implemented by hardware, software (program code), or a combination of hardware and software. If implemented by software, it can be stored in the above-described computer-readable medium. When executed by a processor, the software can perform at least some steps of the disclosed methods.

[0311] In the foregoing specification, embodiments have been described with reference to numerous specific details, which may vary depending on the implementation. Certain adaptations and modifications can be made to the described embodiments. Other embodiments will be apparent to those skilled in the art in consideration of the specification and practice of the disclosure herein. The specification and examples are intended to be illustrative only, and the true scope and spirit of this disclosure are indicated by the appended claims. The order of steps shown in the figures is also for illustrative purposes only and does not imply that all steps must be performed for any given method of operation, nor does it imply that all steps are limited to any particular order. Therefore, those skilled in the art will understand that these steps may be performed in different orders when implementing the same method. Furthermore, the devices shown in the figures are merely illustrative, and a given device or system may include different combinations of components or modules of such devices.

Claims

1. A system for generating nitric oxide, characterized in that, The system includes: An apparatus for generating nitric oxide, the apparatus comprising: A reaction chamber having a liquid region and a gas region, wherein the liquid region is configured to contain a reaction medium and the gas region is configured to contain a product gas including nitric oxide; A plurality of electrodes disposed in the reaction medium, the plurality of electrodes including a cathode; An energy source electrically connected to the plurality of electrodes and configured to apply a predetermined voltage or a predetermined current to the cathode to generate nitric oxide; A sprayer installed in the reaction medium; An inlet circuit, which is in fluid communication with the sprayer and configured to deliver a carrier gas to the sprayer; and An outlet circuit, which is in fluid communication with the gas region of the reaction chamber and configured to deliver the product gas from the reaction chamber; and A pressure vessel in fluid communication with the outlet circuit, the pressure vessel being configured to receive product gas from the outlet circuit, store the received product gas at or below a predetermined pressure, and release the received product gas. The pressure vessel includes: The main body defines an internal cavity including a first region and a second region, the second region being in fluid communication with the first region and disposed downstream of the first region; A gas inlet and a gas outlet in fluid communication with the first region; and Multiple baffles, the multiple baffles defining a tortuous flow path through the first region and the second region; and A pressure relief valve is disposed on the main body and is in fluid communication with the second region; The system further includes an exhaust gas treatment device disposed downstream of the pressure vessel and in fluid communication with the pressure relief valve, the exhaust gas treatment device being configured to reduce or remove one or more nitrogen oxides in the gas received from the pressure vessel via the pressure relief valve.

2. The system according to claim 1, characterized in that, The carrier gas includes nitrogen.

3. The system according to claim 1, characterized in that, The system further includes a first circulation loop configured to circulate a first fluid flow relative to the reaction chamber, the first circulation loop comprising: A first inlet in fluid communication with the gas region of the reaction chamber; A first outlet in fluid communication with the sprayer; and A first pump is configured to generate a first fluid flow from the first inlet to the first outlet.

4. The system according to claim 3, characterized in that, The first fluid flow includes a product gas flow.

5. The system according to claim 1, characterized in that, The sprayer is disposed adjacent to the cathode and is configured to emit bubbles in the reaction medium to propagate along the surface of the cathode.

6. The system according to claim 1, characterized in that, The reaction chamber includes a first side and a second side opposite to the first side, and the cathode includes an electrode plate positioned perpendicular to the second side of the reaction chamber.

7. The system according to claim 6, characterized in that, The electrode plate includes a surface, a first edge, and a second edge opposite to the first edge, the first edge extending along a first side of the reaction chamber, and the second edge extending along a second side of the reaction chamber.

8. The system according to claim 7, characterized in that, The sprayer is disposed between the second side of the reaction chamber and the second edge of the electrode plate, and the sprayer is configured to emit bubbles along a bubble path extending from the second edge of the electrode plate to the first edge.

9. The system according to claim 1, characterized in that, The system further includes a second circulation loop configured to circulate a second fluid flow relative to the reaction chamber, the second circulation loop comprising: A first port in fluid communication with the liquid region of the reaction chamber; A second port in fluid communication with the gas region of the reaction chamber; A second pump, configured to generate a second fluid flow from the first port to the second port or from the second port to the first port; and A liquid-gas separation device is disposed downstream of the second pump and configured to separate nitric oxide from the reaction medium as the reaction medium passes through it.

10. The system according to claim 1, characterized in that, The reaction medium includes a buffer solution, a nitrite ion source, and a catalyst; the catalyst includes a metal-ligand complex; and the nitrite ion source includes one or more nitrites.

11. The system according to claim 1, characterized in that, The predetermined voltage is from 1.4 V to 5.0 V, or the predetermined current is from 0 mA to 600 mA.

12. The system according to claim 1, characterized in that, It further includes a nitric oxide sensor configured to detect the nitric oxide concentration of the product gas.

13. The system according to claim 1, characterized in that, The first area includes a first group of multiple chambers defining a first flow path; and The second region includes a second set of multiple chambers defining a second flow path that is in fluid communication with the first flow path.

14. The system according to claim 1, characterized in that, The pressure vessel further includes a pressure sensor configured to detect the gas pressure in the first region.

15. The system according to claim 1, characterized in that, The system further includes a filtration system disposed downstream of and in fluid communication with the outlet circuit, the filtration system being configured to reduce one or more impurities in the product gas.

16. The system according to claim 3, characterized in that, The system further includes a filtration device disposed downstream of the first inlet of the first circulation loop and upstream of the first pump, the filtration device being configured to reduce or remove one or more liquid and / or solid impurities in the first fluid flow.

17. The system according to claim 1, characterized in that, The exhaust gas treatment device includes a tortuous flow path at least partially filled with filter material configured to react with one or more nitrogen oxides.

18. The system according to claim 1, characterized in that, The device further includes a gas converter disposed downstream of and in fluid communication with the pressure vessel, the gas converter being configured to absorb one or more types of nitrogen dioxide from the product gas and / or convert one or more types of nitrogen dioxide from the product gas into nitric oxide.

19. The system according to claim 1, characterized in that, The system further includes a carrier gas source located upstream of and in fluid communication with the inlet circuit, the carrier gas source being configured to generate the carrier gas or supply the carrier gas to the inlet circuit.

20. The system according to claim 19, characterized in that, The carrier gas source includes a nitrogen generating device configured to generate the carrier gas from compressed air, the nitrogen generating device including a nitrogen separation membrane.

21. The system according to claim 19, characterized in that, The carrier gas contains more than 99.0% nitrogen by volume.

22. The system according to claim 19, characterized in that, The carrier gas source includes a flow control device configured to control the flow rate of the carrier gas to the inlet loop.

23. The system according to claim 1, characterized in that, It further includes a ventilation circuit configured to connect to a breathing apparatus, the ventilation circuit including an inhalation circuit disposed downstream of the breathing apparatus and the pressure vessel and in fluid communication with the breathing apparatus and the pressure vessel.

24. The system according to claim 23, characterized in that, The intake circuit includes: An inlet configured to receive an airflow or oxygenflow from the breathing device; A port located downstream of the inlet is configured to receive product gas from the pressure vessel; A flow sensor, disposed downstream of the inlet and configured to measure the flow rate of the airflow or the oxygenflow; and An outlet configured to deliver a gas mixture comprising product gas from the pressure vessel and air or oxygen from the breathing apparatus.

25. The system according to claim 24, characterized in that, The intake circuit further includes a sampling port located upstream of the outlet and configured to output a sample gas stream of the gas mixture.

26. The system according to claim 25, characterized in that, The device further includes a gas monitoring device comprising one or more gas sensors configured to receive the sample gas stream and measure the concentration of one or more of nitrogen dioxide, nitric oxide, and oxygen in the sample gas stream.

27. The system according to claim 26, characterized in that, Further includes: A flow control device configured to control the flow rate of the product gas entering the intake circuit from the pressure vessel; A control device that communicates with the flow sensor, the flow control device, and the gas monitoring device, wherein the control device is configured to... Receive one or more sensing signals or readings from the gas monitoring device and / or the flow sensor; Instructions are generated based on one or more sensing signals or readings; and The instruction is sent to the flow control device to adjust the flow rate of the product gas entering the intake circuit.

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