System and method for obtaining nitrogen and carbon dioxide from flue gas

Abstract

A system and method are provided for obtaining nitrogen and carbon dioxide gas from flue gas. A method according to some embodiments involves receiving flue gas at the inlet of a selective catalytic reduction system, wherein the flue gas is one or more NO x The system includes a gas and one or more NOs in a selective catalytic reduction system. x The method includes reducing a gas to N2 gas, receiving output gas from a selective catalytic reduction system at the inlet of a gas separation membrane, and separating the output gas into a retained substance and a permeate using the gas separation membrane, wherein the retained substance comprises N2 gas.

Description

[Technical Field]

[0001] (Cross-reference of related applications) This application claims priority and interest in U.S. Provisional Application No. 63 / 492,999, filed on 29 March 2023, which is incorporated herein by reference as a whole.

[0002] (Field) The present invention generally relates to the isolation of components of gas mixtures, and more specifically to systems and methods for obtaining nitrogen and carbon dioxide gases from flue gas. [Background technology]

[0003] (background) Industrial combustion processes produce flue gas containing reaction byproducts such as carbon dioxide, water, and other gaseous compounds. Some of these reaction byproducts can be undesirable pollutants. For example, some combustion processes are carried out using ambient air rather than pure oxygen, so nitrogen from the air reacts with oxygen to form nitrogen oxides (NOx). x ) may form gas. NO x Gases can be harmful to human health and the environment; therefore, it is desirable to remove them from flue gases before releasing them into the atmosphere. [Overview of the project] [Means for solving the problem]

[0004] (summary) Flue gases produced by the combustion process are NO x It may contain harmful reaction by-products such as gases. If released into the atmosphere without being reduced to inert nitrogen gas, NO x Gas can have harmful health effects and can damage the environment. NO x The harmful potential of the gas is NO xcan be eliminated by reducing it to nitrogen (N2) gas. N2 gas has numerous applications in fields such as the chemical, food, and medical industries. Therefore, it may be desirable to develop a system and method for obtaining N2 gas from NO x containing flue gas.

[0005] Furthermore, CO2 may also be present in flue gas. CO2 is a greenhouse gas that can be harmful to the environment when released into the atmosphere. CO2 also has several industrial and food-grade uses. Therefore, it may also be desirable to develop a system and method for obtaining CO2 gas from flue gas. What is disclosed herein are exemplary systems and methods for obtaining nitrogen and carbon dioxide gases from flue gas.

[0006] In some embodiments, a method for obtaining nitrogen gas from flue gas is to receive the flue gas at the inlet of a selective catalytic reduction system, where the flue gas comprises one or more NO x gases, and to reduce one or more NO x gases to N2 gas within the selective catalytic reduction system, to receive the output gas from the selective catalytic reduction system at the inlet of a gas separation membrane, and to separate the output gas into a retentate and a permeate using the gas separation membrane, where the retentate comprises N2 gas. In some embodiments, the source of the flue gas is pyrolysis gas, biogas, or natural gas. In some embodiments, the method comprises combusting methane gas within a burner / boiler system, producing flue gas, and transporting the flue gas to the inlet of a selective catalytic reduction system. In some embodiments, the flue gas is NO xThe selective catalytic reduction system comprises one or more of the following: N2, CO2, CO, H2O, O2, CH4, C2H6, Ar, SOx, or volatile organic compounds. In some embodiments, the selective catalytic reduction system comprises a reducing agent. In some embodiments, the reducing agent comprises ammonia or urea. In some embodiments, the selective catalytic reduction system comprises one or more catalysts. In some embodiments, one or more catalysts include a copper zeolite catalyst, an iron zeolite catalyst, or a platinum-based oxidation catalyst. In some embodiments, the selective catalytic reduction system comprises a controller. In some embodiments, the selective catalytic reduction system comprises one or more NO x Equipped with a sensor, NO x The sensor detects NO from the output gas of the selective catalytic reduction system. x Determine the content. In some embodiments, the controller determines one or more NO x NO determined from the sensor x The method is configured to adjust the flow rate of the reducing agent based on its content. In some embodiments, the method includes compressing the output gas from a selective catalytic reduction system to a compressed output, removing water from the compressed output, and receiving the compressed output at the inlet of a gas separation membrane. In some embodiments, the gas separation membrane includes a hollow fiber membrane. In some embodiments, the retainer comprises at least 85% by weight of N2. In some embodiments, the permeate comprises at least 35% by weight of CO2. In some embodiments, the permeate comprises N2, CO2, CO, CH4, C2H6, H2O, Ar, O2, or NO xThe method comprises one or more of the following. In some embodiments, the method includes isolating the permeate in a ground injection site. In some embodiments, the method includes separating the permeate into a CO2 stream and a waste gas stream. In some embodiments, separating the permeate into a CO2 stream and a waste gas stream includes receiving the permeate at the inlet of a CO2-selective gas separation membrane and separating the permeate using the CO2-selective gas separation membrane into a waste gas stream having CO2-poor reserves and a CO2 stream having CO2-rich permeate, wherein the CO2-rich permeate comprises CO2 gas. In some embodiments, the CO2-rich permeate comprises at least 92% by weight of CO2. In some embodiments, the method includes SO2 from flue gas. x This includes removing SO from flue gas. x Removing dust includes wet scrubbing or dry scrubbing. In some embodiments, the method includes removing dust from flue gas, which includes using one or more baghouses, one or more ceramic filters, or one or more electrostatic precipitators. In some embodiments, the method includes removing water from output gas from a selective catalytic reduction system, compressing the output gas to a compressed output, and receiving the compressed output at the inlet of a gas separation membrane.

[0007] In some embodiments, a system for obtaining nitrogen gas from flue gas is a selective catalytic reduction system, which receives flue gas at the inlet of the selective catalytic reduction system, wherein the flue gas is one or more NO x Having gas and one or more NO xA selective catalytic reduction system configured to reduce a gas to N2 gas, and a gas separation membrane configured to receive, at an inlet of the gas separation membrane, an output gas from the selective catalytic reduction system and separate the output gas into a retained substance and a permeate, the retained substance comprising N2 gas. In some embodiments, the system includes a compressor configured to receive, at an inlet of the compressor, the output gas from the selective catalytic reduction system and compress the output gas from the selective catalytic reduction system to a compressed output. In some embodiments, the system includes a water removal system configured to receive, at an inlet of the water removal system, the compressed output, remove water from the compressed output, and transport the compressed output from an outlet of the water removal system to an inlet of the gas separation membrane. In some embodiments, the system includes a burner / boiler system configured to produce flue gas and transport the flue gas to an inlet of the selective catalytic reduction system. In some embodiments, the system includes a water removal system configured to receive, at an inlet of the water removal system, the output gas from the selective catalytic reduction system, remove water from the output gas from the selective catalytic reduction system, and produce a dried output gas. In some embodiments, the system includes a compressor configured to receive, at an inlet of the compressor, the dried output gas, compress the dried output gas to a compressed output, and transport the compressed output from an outlet of the compressor to an inlet of the gas separation membrane.

[0008] As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context explicitly indicates otherwise. Furthermore, as used herein, the terms “and / or” refer to and encompass any possible combination of one or more of the enumerated articles relating to them, as well as all of them. It should also be understood that, when used herein, the terms “includes,” “including,” “comprises,” and / or “comprising” specify the existence of the described features, integers, steps, actions, elements, components, and / or units, but do not exclude the existence or addition of one or more other features, integers, steps, actions, elements, components, units, and / or groups thereof.

[0009] It is to be understood that aspects and embodiments described herein include the aspects and embodiments with the transitional terms “consisting” and / or “consisting essentially of”. For all methods, systems, compositions, and devices described herein, the methods, systems, compositions, and devices can either comprise the recited components or steps or can “consist of” or “consist essentially of” the recited components or steps. When a system, composition, or device is described as “consisting essentially of” the recited components, the system, composition, or device contains the recited components and may contain other components that do not substantially affect the performance of the system, composition, or device, but does not contain any other components that substantially affect the performance of the system, composition, or device or contain a sufficient concentration or amount of residual components that substantially affect the performance of the system, composition, or device other than those explicitly recited components. When a method is described as “consisting essentially of” the recited steps, the method contains the recited steps and may contain other steps that do not substantially affect the outcome of the method, but the method does not contain any other steps that substantially affect the outcome of the method other than those explicitly recited steps.

[0010] In this disclosure, in various embodiments, "substantially free of" a specific component, specific composition, specific compound, or specific raw material means that it is present in weight percentages of less than 5%, less than 2%, less than 1%, less than 0.5%, less than 0.1%, less than 0.05%, less than 0.025%, or less than 0.01% of that specific component, specific composition, specific compound, or specific raw material. Preferably, "substantially free of" a specific component, specific composition, specific compound, or specific raw material means that it is present in weight percentages of less than 1% of that specific component, specific composition, specific compound, or specific raw material.

[0011] Additional advantages will be readily apparent to those skilled in the art from the following detailed description. The examples and descriptions herein should be considered non-restrictive and in essence illustrative. [Brief explanation of the drawing]

[0012] [Figure 1] The single figure is a process flow diagram representing a system for obtaining nitrogen and carbon dioxide gas from flue gas, according to several embodiments. [Modes for carrying out the invention]

[0013] (Detailed explanation) This specification describes exemplary systems and methods for obtaining nitrogen and carbon dioxide gases from flue gas. The systems and methods described herein can address the problems described above. Specifically, this system addresses harmful NO x The gas can be reduced to inert nitrogen gas, which can then be separated and used in other processes. In addition, the system disclosed herein can isolate CO2 gas, which can also be purified and used in other processes.

[0014] The single figure is a process flow diagram representing an exemplary system 100 for obtaining nitrogen and carbon dioxide gas from flue gas. This system includes a burner / boiler system 102, a first compressor 104, a controller 108, and NO x The system may include a selective catalytic reduction system 106 with a sensor 110, a storage tank 112, a water removal system 114, a second compressor 116, a gas separation membrane 118, a CO2 separation system 120, and / or a isolation system 122.

[0015] In some embodiments, flue gas can be produced by burning pyrolysis gas, biogas, and / or methane gas using combustion air in a burner of a burner / boiler system 102. As used in this application, flue gas can refer to any waste gas stream containing combustion products. In some embodiments, flue gas is NO x , N2, CO2, CO, H2O, O2, CH4, C2H6, Ar, SO x It may also comprise one or more of the following: and / or volatile organic compounds.

[0016] In some embodiments, pyrolysis gas is burned in the burner of the burner / boiler system 102. The pyrolysis gas may be produced using a biomass input. As used in this application, the biomass input may refer to bio-derived materials. In some embodiments, the biomass input may include woody biomass such as wood chips or sawdust, agricultural waste such as grapevine pruning, oat and rice husks, or wheat and oat straw, sewage waste, or a combination thereof. In some embodiments, methane gas is burned in the burner of the burner / boiler system 102. In some embodiments, the resulting flue gas may be fed from the boiler outlet of the burner / boiler system 102 to the inlet of the selective catalytic reduction system 106. In some embodiments, the boiler of the burner / boiler system 102 may have power ratings of approximately 0.01 to 50 MW, approximately 0.1 to 25 MW, approximately 0.2 to 10 MW, approximately 0.3 to 5 MW, approximately 0.4 to 1 MW, or approximately 0.5 MW.

[0017] In some embodiments, the flue gas from the burner / boiler system 102 can be about 0.1–10 psig, about 1–10 psig, about 2–9 psig, about 4–6 psig, or about 5 psig before being supplied to the selective catalytic reduction system 106. In some embodiments, the flue gas can be about 10–1,000°C, about 50–500°C, about 100–400°C, about 150–350°C, or about 200–300°C.

[0018] In some embodiments, the flue gas from the burner / boiler system 102 is fed to the selective catalytic reduction system 106 to collect and remove dust or SO4 before it is supplied. x The gas can be pre-treated to reduce it. Dust may be present in the flue gas when the solid fuel is burned in the burner of the burner / boiler system 102. x This may be present in the flue gas if the fuel ignited in the burner / boiler system 102 has a significant amount of sulfur. Collect the dust and then remove it or SO x Reducing the gas can improve the function of the gas separation membrane 118. Dust can accumulate on or within the membrane, which can cause membrane contamination. x The polymer used to produce the gas separation membrane 118 may react with the membrane, which can impair its function. Therefore, dust and SO4 may react with the polymer. x Eliminating SO2 can prevent film contamination. In addition, x Removing SO4 may improve the function of the selective catalytic reduction system 106. x These may react with ammonia or urea to form salts that can contaminate the catalyst used in the selective catalytic reduction system 106.

[0019] In some embodiments, dust can be collected using one or more baghouses. The baghouse may comprise one or more cloth bag filters that are not permeable to the gas but prevent dust from passing through the filter. In some embodiments, dust can be collected using one or more ceramic filters. The ceramic filters may be permeable to the gas but can prevent dust from passing through the filter. In some embodiments, dust can be collected using one or more electrostatic precipitators (ESPs). The ESPs may include electrodes that produce an ionization field. Flue gas may flow through the ionization field, which can negatively charge dust particles in the flue gas. An additional positively charged electrode may be placed in the ionization field to attract load-charged dust particles, which may then be collected from the positively charged electrode.

[0020] In some embodiments, SO in flue gas x The gas can be reduced using a wet scrubbing technique. In wet scrubbing, the flue gas may pass through a wetted surface or water may be sprayed onto it. x It can react with gas to produce sulfuric acid (H2SO4). Sulfuric acid can be neutralized using a basic material (e.g., NaOH, Na2CO3, Ca(OH)2, etc.). In some embodiments, SO4 in flue gas x The gas can be reduced using the dry scrubbing technique. In dry scrubbing, solid particles (e.g., Ca(OH)2, Na2CO3, CaCO3, etc.) or their slurry are reduced to SO x It can react with gases to produce particulate matter (e.g., CaSO3, Na2SO3).

[0021] In some embodiments, the compressor 104 can compress a gas (e.g., air) to be supplied to the selective catalytic reduction system 106. In some embodiments, the compressor 104 may comprise a horizontal or vertical compressor with a tank. In some embodiments, the compressor 104 can operate at ambient temperature. In some embodiments, the compressor can compress the gas to at least about 50 psig, at least about 60 psig, at least about 70 psig, or at least about 80 psig. In some embodiments, the compressor can compress the gas to a maximum of about 110 psig, a maximum of about 100 psig, a maximum of about 90 psig, or a maximum of about 80 psig. In some embodiments, the compressed gas may be supplied to the selective catalytic reduction system 106 to provide additional O2 for the oxidation catalyst contained within the selective catalytic reduction system 106 and to reduce volatile organic compounds or CO in the flue gas. The compressed gas may also serve as a sweeping function to clean the catalytic pores of one or more catalysts in the SCR system 106.

[0022] In some embodiments, the selective catalytic reduction (SCR) system 106 uses one or more catalysts to reduce NO x The system includes a reducing agent for selectively reducing the gas to N2 gas (and water). In some embodiments, flue gas from the boiler of the burner / boiler system 102 and compressed air from the compressor 104 can be received at one or more inlets of the SCR system 106. In some embodiments, the reducing agent from the storage tank 112 also includes NO in the flue gas. x To facilitate the reduction of gas to N2, a reducing agent can be supplied to the inlet of the SCR system 106. In some embodiments, the reducing agent may comprise ammonia or urea. In some embodiments, the reducing agent and flue gas may be mixed prior to entering the SCR system 106.

[0023] In some embodiments, the SCR system 106 comprises one or more catalysts to facilitate the reduction reaction. In some embodiments, the catalyst may comprise copper zeolite and / or iron zeolite. In some embodiments, the flue gas may comprise CO and volatile organic compounds (VOCs). In some embodiments, an oxidation catalyst may be included to oxidize CO and decompose VOCs. In some embodiments, the oxidation catalyst is a platinum-based catalyst. In some embodiments, one or more catalysts may be held within a stainless steel housing unit in the SCR system 106.

[0024] In some embodiments, the SCR system 106 includes a controller 108 for adjusting the amount of reducing agent supplied to the system from a storage tank 112. In some embodiments, the controller 108 includes a carbon steel frame and a screen. In some embodiments, the controller 108 includes one or more temperature sensors and one or more NO sensors. x It can be connected to sensor 110.

[0025] In some embodiments, the SCR system 106 has one or more NO x It is equipped with a sensor 110. In some embodiments, one or more NO x Sensors 110 may be installed at the inlet and outlet of the SCR system 106 and may be coupled to the controller 108. In some embodiments, the sensors detect NO from the output gas of the SCR system 106. x NO enters and exits the SCR system 106 to determine its content. x The amount of NO can be monitored using a sensor. x Based on the amount, the controller 108 can be used to adjust the flow rate of the reducing agent released from the storage tank 112 into the SCR system 106. In some embodiments, monitoring and adjusting the reducing agent flow rate accordingly can reduce the amount of excess reducing agent that passes through the SCR system 106 unreacted.

[0026] In some embodiments, the output gas from the SCR system 106 can be fed to the inlet of a water removal system 114. In some embodiments, the water removal system 114 can remove liquid water from the output gas from the SCR system 106, leaving the remaining components of the output in gaseous form. In some embodiments, the water removal system 114 can be a triethylene glycol (TEG) dehydration system and / or a desiccant dryer. In some embodiments, the water removal system 114 can be a heat exchanger. In some embodiments, water may be removed before feeding the output gas from the SCR system 106 to the gas separation membrane 118, as condensed water within the membrane can cause fouling. In some embodiments, feeding the output gas from the SCR system 106 to the water removal system 114 before the compressor 116 can reduce the energy required to operate the compressor 116. In some embodiments, prior to water removal, the output gas from the SCR system 106 can be about 10–1,000°C, about 50–500°C, about 100–300°C, about 150–250°C, or about 200°C. In some embodiments, prior to water removal, the output gas from the SCR system 106 can be about ambient pressure, or about 0.1–10 psig, about 1–10 psig, about 2–9 psig, about 4–6 psig, or about 5 psig.

[0027] In some embodiments, the output gas from the water removal system 114 is approximately 0-50°C, 1-30°C, 2-20°C, 3-10°C, 4-6°C, or 5°C. In some embodiments, the output gas from the water removal system 114 is approximately 0.1-10 psig, 1-8 psig, 2-5 psig, or 3 psig. In some embodiments, the output gas from the water removal system 114 can be supplied to the inlet of the compressor 116.

[0028] In some embodiments, the compressor 116 compresses the output gas from the water removal system 114 to about 10–500 psig, about 50–400 psig, about 100–400 psig, about 150–400 psig, about 200–350 psig, about 250–300 psig, or about 275 psig in order to produce a compressed output. In some embodiments, at this temperature and / or pressure, the compressed output may include a gaseous mixture containing a liquid (e.g., water) and other components of the output gas. In some embodiments, the compressor 116 may be an industrially sized compressor that can be fitted onto a skid for transport.

[0029] In some embodiments, the compressor 116 may include a final cooler. In some embodiments, the final cooler may be mounted on a skid for transport together with the compressor 116. In some embodiments, the coolant used in the final cooler is water. In some embodiments, the water may be at approximately ambient temperature. The final cooler may cool the temperature of the compression output of the compressor 116 to a desired temperature for input to the gas separation membrane 118. In some embodiments, the final cooler may cool the compression output to a temperature below about 100°C, below about 90°C, below about 80°C, below about 70°C, below about 60°C, below about 50°C, or below 40°C. In some embodiments, the final cooler may cool the compression output to about 1 to 100°C, about 10 to 80°C, about 20 to 60°C, about 30 to 50°C, about 35 to 45°C, or about 40°C.

[0030] In some embodiments, the compressor 116 may be positioned before the water removal system 114 such that the output gas from the SCR system 106 is received at the inlet of the compressor 116 and the compressed output from the compressor 116 is received at the inlet of the water removal system 114. In some embodiments, when the compressor 116 is used before the water removal system 114, the output gas from the SCR system 106 can be supplied to the inlet of the compressor 116. The compressor 116 may compress the output gas from the SCR system 106 to about 10-500 psig, about 50-400 psig, about 100-400 psig, about 150-400 psig, about 200-350 psig, about 250-300 psig, or about 275 psig in order to produce a compressed output. In some embodiments, at this temperature and / or pressure, the compressed output may include a gaseous mixture containing a liquid (e.g., water) and other components of the output gas.

[0031] In some embodiments, if the compressor 116 is used before the water removal system 114, the compressed output can be received at the inlet of the water removal system 114. In some embodiments, the water removal system 116 can remove liquid water from the compressed output, leaving the remaining components of the compressed output in gaseous form. In some embodiments, the water removal system 114 may also cool the compressed output to a temperature below about 100°C, below about 90°C, below about 80°C, below about 70°C, below about 60°C, or below about 50°C. In some embodiments, the water removal system 114 may cool the compressed output to about 20–100°C, about 25–75°C, about 30–50°C, or about 40°C. In some embodiments, the water removal system 114 may cool the compressed output to a desired temperature for input to the gas separation membrane 118.

[0032] In some embodiments, the compression output can be received at the inlet of the gas separation membrane 118 and passed across the membrane. In some embodiments, the gas separation membrane 118 can be a polymer gas separation membrane. In some embodiments, the gas separation membrane 118 can be a hollow fiber membrane. In some embodiments, the membrane fibers may be contained within one or more cylindrical capsules.

[0033] In some embodiments, passing the compression output across the gas separation membrane 118 separates the gas into an N2-rich retainer and a permeate that is N2-poor compared to the retainer. In some embodiments, the retainer pressure is about 10–500 psig, about 50–400 psig, about 100–400 psig, about 150–400 psig, about 200–350 psig, about 250–300 psig, or about 275 psig, and the permeate pressure is about 0.1–10 psig, about 1–10 psig, about 2–9 psig, about 4–6 psig, about 4–5 psig, or about 4.4 psig. In some embodiments, the retained material temperature is about 1 to 100°C, about 10 to 80°C, about 20 to 60°C, about 30 to 50°C, about 35 to 45°C, or about 40°C, and the permeate temperature is about 1 to 100°C, about 10 to 80°C, about 20 to 60°C, about 30 to 50°C, about 35 to 45°C, or about 40°C.

[0034] In some embodiments, the retainer is N2, CO2, CO, CH4, C2H6, O2, Ar, or NO xIt comprises one or more of the following. In some embodiments, the reserve may comprise nitrogen at a weight ratio of about 80–99.99% or N2 at a weight ratio of about 85–99%. In some embodiments, the reserve may comprise nitrogen at a maximum of about 99.99% by weight, a maximum of about 99.5% by weight, a maximum of about 99% by weight, a maximum of about 98% by weight, a maximum of about 97% by weight, a maximum of about 96% by weight, a maximum of about 95% by weight, a maximum of about 90% by weight, or a maximum of 85% by weight. In some embodiments, the reserve may contain at least about 50% by weight, at least about 55% by weight, at least about 60% by weight, at least about 65% by weight, at least about 70% by weight, at least about 75% by weight, at least about 80% by weight, at least about 85% by weight, at least about 86% by weight, at least about 87% by weight, at least about 88% by weight, at least about 89% by weight, at least about 90% by weight, at least about 92% by weight, or at least about 95% by weight of nitrogen. In some embodiments, the reserve may be stored and sold for use in processes requiring high-purity nitrogen gas.

[0035] In some embodiments, the permeate is N2, CO2, CO, CH4, C2H6, H2O, Ar, O2, or NO x It comprises one or more of the following. In some embodiments, the permeate may contain CO2 at a weight ratio of about 25–75%, about 25–50%, about 30–50%, or about 35–49%. In some embodiments, the permeate may contain carbon dioxide at a maximum of about 65% by weight, up to about 60% by weight, up to about 55% by weight, up to about 50% by weight, up to about 49% by weight, up to about 48% by weight, up to about 47% by weight, up to about 45% by weight, or up to 40% by weight. In some embodiments, the permeate may contain at least about 25% by weight, at least about 30% by weight, at least about 35% by weight, at least about 36% by weight, at least about 37% by weight, at least about 38% by weight, at least about 39% by weight, at least about 40% by weight, at least about 41% by weight, at least about 42% by weight, at least about 43% by weight, at least about 44% by weight, at least about 45% by weight, at least about 46% by weight, or at least about 47% by weight of carbon dioxide.

[0036] In some embodiments, since the permeate is rich in CO2, one or more additional steps may be taken to isolate the CO2 from the permeate for further processing or for use in applications requiring high-purity CO2 gas. In some embodiments, the permeate is fed to a CO2 separation system 120 instead of, or in addition to, feeding to an isolation system 122. In some embodiments, the separation system 120 can separate the permeate into a CO2 stream and a waste gas stream. In some embodiments, the separation system 120 may use an absorption technique to isolate CO2 from other components of the permeate. In some embodiments, one or more liquid amine absorbents may be used to attract CO2 and separate it from other components of the gas. In some embodiments, after the CO2 has been absorbed by the absorbent, a pure stream of CO2 may be removed from the absorbent by increasing the temperature and / or pressure. In some embodiments, the separation system 120 may use an adsorption technique to isolate CO2 from other components of the permeate. In some embodiments, the CO2 may adhere to the surface of one or more solid adsorbents to separate the CO2 from other components of the gas. In some embodiments, the solid adsorbent may be a molecular sieve. In some embodiments, after CO2 has been adsorbed by the adsorbent, a pure stream of CO2 may be removed from the adsorbent by increasing the temperature and / or pressure.

[0037] In some embodiments, the CO2 stream may be purified to a purity of about 90–99.99% by weight or about 90–99.95% by weight for industrial and food-grade applications. In some embodiments, the CO2 stream contains up to about 99.99% by weight, up to about 99.5% by weight, up to about 99% by weight, up to about 98% by weight, up to about 97% by weight, up to about 96% by weight, up to about 95% by weight, or up to about 90% by weight of carbon dioxide. In some embodiments, the CO2 stream may contain at least about 90% by weight, at least about 91% by weight, at least about 92% by weight, at least about 93% by weight, at least about 94% by weight, at least about 95% by weight, at least about 96% by weight, at least about 97% by weight, at least about 98% by weight, or at least about 99% by weight of carbon dioxide.

[0038] In some embodiments, the CO2 separation system 120 may use membrane techniques to isolate CO2 from other components of the permeate from the gas separation membrane 118. In some embodiments, the permeate from the gas separation membrane 118 can be received at the inlet of a CO2-selective gas separation membrane of the CO2 separation system 120 and passed across the membrane. In some embodiments, the CO2-selective gas separation membrane can be an facilitated transport membrane. In some embodiments, the facilitated transport membrane can contain one or more amine carriers. In some embodiments, passing the permeate from the gas separation membrane 118 across the CO2-selective gas separation membrane separates the gas into a CO2-rich permeate and a CO2-poor reserve compared to the permeate.

[0039] In some embodiments, the CO2-rich permeate from the CO2-selective gas separation membrane is N2, CO2, CO, CH4, C2H6, H2O, Ar, O2, or NO xOne or more of the above may be included. In some embodiments, the permeate from the CO2 selective gas separation membrane may consist of about 92–99% by weight of CO2. In some embodiments, the permeate from the CO2 selective gas separation membrane may consist of up to about 99%, up to about 98%, up to about 97%, up to about 96%, up to about 95%, up to about 94%, or up to about 93% by weight of CO2. In some embodiments, the permeate from the CO2 selective gas separation membrane may consist of at least about 92% by weight, at least about 93%, at least about 94%, at least about 95%, at least about 96%, at least about 97%, or at least about 98% by weight of CO2. In some embodiments, the pressure of the permeate from the CO2 selective gas separation membrane is about 0–10 psig, about 0–5 psig, about 0–1 psig, or about ambient pressure. In some embodiments, the temperature of the permeate from the CO2 selective gas separation membrane is approximately 1–100°C, approximately 10–80°C, approximately 20–60°C, approximately 30–50°C, approximately 35–45°C, or approximately 40°C.

[0040] In some embodiments, the CO2-poor residue from the CO2-selective gas separation membrane is N2, CO2, CO, CH4, C2H6, H2O, Ar, O2, or NO x One or more of these may be provided. In some embodiments, the pressure of the retained material from the CO2 selective gas separation membrane is about 0.1–10 psig, about 1–10 psig, about 2–9 psig, about 4–6 psig, about 4–5 psig, or about 4.4 psig. In some embodiments, the temperature of the retained material from the CO2 selective gas separation membrane is about 1–100°C, about 10–80°C, about 20–60°C, about 30–50°C, about 35–45°C, or about 40°C. In some embodiments, the CO2-poor retained material can be discharged into the atmosphere.

[0041] In some embodiments, the permeate from the gas separation membrane 118 is fed to an isolation system 122 instead of, or in addition to, being fed to a CO2 separation system 120. In some embodiments, the isolation system 122 isolates the permeate from the gas separation membrane 118 within a ground injection site. In some embodiments, the isolation system 122 may comprise an injection well and a conduit for transporting the permeate from the gas separation membrane 118 into the injection well. In some embodiments, the injection well may be drilled near the CO2 production facility, or an existing injection well may be used. In some embodiments, the conduit used to transport CO2 to the injection well may be a pipeline. In some embodiments, the CO2 is transported to the well in a liquid state. In some embodiments, the CO2 is transported to the well in a gaseous state.

[0042] Specific examples of systems and methods for obtaining nitrogen gas from flue gas, according to several embodiments, are described further below.

[0043] (Examples) (Example 1: Acquisition of nitrogen from flue produced from biomass input) Biomass pyrolysis was performed at approximately 1,000°C and 5 psig using 186.71 kg / hour of dry biomass to produce pyrolysis gases. The pyrolysis gases were produced by pyrolysis and gasification of wood chips. The resulting pyrolysis gases consisted of 2.00 kg / hour of H2, 94.00 kg / hour of N2, 72.55 kg / hour of CO2, 40.02 kg / hour of CO, 8.81 kg / hour of CH4, 13.22 kg / hour of C2H6, 3.30 kg / hour of primary tar, 3.10 kg / hour of secondary tar, 44.18 kg / hour of H2O, and 1.60 kg / hour of Ar. The primary tar was assumed to be acetic acid, and the secondary tar was assumed to be phenol. The pyrolysis gas flow rate was calculated by combining the air used for gasification and all the volatile substances released from the dry biomass. It was assumed that all gases, including pyrolysis gases, behaved as ideal gases. [Table 1]

[0044] The pyrolysis gas was mixed with combustion air at a rate of 636.77 kg / hour under ambient conditions. The combustion air contained 480.86 kg / hour of N2, 0.39 kg / hour of CO2, 147.35 kg / hour of O2, and 8.17 kg / hour of Ar. The combustion air was supplied with a 20% surplus. [Table 2]

[0045] A mixture of pyrolysis gas and combustion air was introduced into the boiler system and combusted. Primary and secondary tars were removed via filtration before the mixture entered the boiler system. The boiler had a power rating of 0.5 MW and operated at approximately 85% efficiency. The flue gas produced by the boiler system contained 574.83 kg / hour of N2, 197.49 kg / hour of CO2, 0.736 kg / hour of CO, 0.007 kg / hour of CH4, 0.007 kg / hour of C2H6, 105.54 kg / hour of H2O, 24.72 kg / hour of O2, 9.77 kg / hour of Ar, and 0.12 kg / hour of NO. x It also had 0.04 kg / hour of SO2. All NO x However, it was assumed to be NO2. x CO and VOC emissions were calculated using emission coefficients. [Table 3]

[0046] Flue gas was supplied to the selective catalytic reduction (SCR) system. Compressed air at 80 psig at 16.37 kg / hour was also supplied to the SCR system. Ammonia was used as a reducing agent for the SCR system. 0.18 kg / hour of aqueous ammonia was supplied to the SCR system. Ammonia is NO x It was supplied in an amount stoichiometrically equivalent to the amount of [the other substance].

[0047] In the SCR system, NO2 was reduced to N2 and H2O by ammonia. CO, CH4, and C2H6 also reacted with O2 in the SCR system to produce CO2 and H2O, as illustrated below.

number

[0048] The output of the SCR system is 587.27 kg / hour of N2, 198.57 kg / hour of CO2, 0.07 kg / hour of CO, 0.0014 kg / hour of CH4, 0.0014 kg / hour of C2H6, 105.65 kg / hour of H2O, 28.09 kg / hour of O2, 9.98 kg / hour of Ar, and 0.019 kg / hour of NO. x It also had 0.037 kg / hour of SO2. The reduction efficiency of the SCR system was NO x The reduction efficiencies were 85% for C2H6, 90% for CO, 80% for CH4, and 80% for C2H6. The reduction efficiency of the SCR system was based on the reduction efficiency of a typical SCR operation. [Table 4]

[0049] The output from the SCR system was processed before being transported to the nitrogen-selective gas separation membrane. The SCR system output was received by a water removal system, which removed liquid water from the SCR system output. The dried output was then fed to a compressor, which compressed the dried output to 275 psig. The dried compressed output contained 587.27 kg / hour of N2, 198.57 kg / hour of CO2, 0.07 kg / hour of CO, 0.0014 kg / hour of CH4, 0.0014 kg / hour of C2H6, 0.85 kg / hour of H2O, 28.09 kg / hour of O2, 9.98 kg / hour of Ar, and 0.019 kg / hour of NO. x It also had a SO2 output of 0.037 kg / hour. [Table 5]

[0050] A dried compressed output was passed through a nitrogen-selective gas separation membrane. The gas separation membrane was a hollow fiber membrane. The membrane separated the gas into an N2-rich retain and a CO2-rich permeate. Membrane separation was modeled from a currently operating membrane.

[0051] The retained material was N2 at 99.42% by weight. The retained material consisted of 425.53 kg / hour of N2, 0.71 kg / hour of CO2, 0.048 kg / hour of CO, 0.001 kg / hour of CH4, 0.001 kg / hour of C2H6, 0.36 kg / hour of O2, 1.37 kg / hour of Ar, and 0.008 kg / hour of NO. x It was equipped with [the following]. [Table 6]

[0052] The permeate consisted of 51.84% CO2 by weight. The permeate also included 161.73 kg / hour of N2, 197.86 kg / hour of CO2, 0.026 kg / hour of CO, 0.000068 kg / hour of CH4, 0.000014 kg / hour of C2H6, 0.85 kg / hour of H2O, 27.72 kg / hour of O2, 8.61 kg / hour of Ar, and 0.018 kg / hour of NO. x It was equipped with [the following]. [Table 7]

[0053] The permeate passes through a CO2-selective gas separation membrane, and the permeate from the first gas separation membrane can be further separated into a CO2-rich permeate and a CO2-poor retained substance compared to the permeate.

[0054] This application discloses several numerical ranges in text and figures. The disclosed numerical ranges are such that this disclosure can be practiced throughout the entire disclosed numerical range, and even if precise range limits are not explicitly stated herein, this disclosure essentially supports any range or value within the disclosed numerical range, including the endpoint.

[0055] The above description is provided to enable those skilled in the art to construct and use this disclosure, and is provided in the context of a particular use and its requirements. Various modifications to the preferred embodiments will readily become apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and uses without departing from the spirit and scope of this disclosure. Thus, this disclosure is not intended to be limited to the embodiments shown, but should be harmonized with the broadest scope consistent with the principles and features disclosed herein. Finally, the entire disclosures of patents and published documents referenced herein are incorporated herein by reference.

Claims

1. A method for obtaining nitrogen gas from flue gas, The system involves receiving flue gas at the inlet of a selective catalytic reduction system, wherein the flue gas is one or more NOs. ｘ To have gas, Within the selective catalytic reduction system, one or more NO ｘ Gas to N ２ Reducing it to gas, At the inlet of the gas separation membrane, the output gas from the selective catalytic reduction system is received, The process involves separating the output gas into a retained substance and a permeate using the gas separation membrane, wherein the retained substance is N ２ To have gas and Methods that include...

2. The method according to claim 1, wherein the source of the flue gas is a pyrolysis gas, a biogas, or methane gas.

3. Combusting methane gas in a burner / boiler system, To produce flue gas, Transporting the flue gas to the inlet of the selective catalytic reduction system The method according to claim 2, further comprising:

4. The flue gas contains NO ｘ , N ２ , CO ２ , CO, H ２ O, O ２ , CH ４ , C ２ H ６ , Ar, SO ２ or one or more of volatile organic compounds, the method according to any one of claims 1 to 3.

5. The method according to any one of claims 1 to 4, wherein the selective catalytic reduction system comprises a reducing agent.

6. The method according to claim 5, wherein the reducing agent comprises ammonia or urea.

7. The method according to any one of claims 1 to 6, wherein the selective catalytic reduction system comprises one or more catalysts.

8. The method according to claim 7, wherein the one or more catalysts include a copper zeolite catalyst, an iron zeolite catalyst, or a platinum-based oxidation catalyst.

9. The method according to any one of claims 1 to 8, wherein the selective catalytic reduction system comprises a controller.

10. The aforementioned selective catalytic reduction system includes one or more NO ｘ Equipped with a sensor, the NO ｘ The sensor detects NO from the output gas of the selective catalytic reduction system. ｘ The method according to claim 9 for determining the content.

11. The controller is one or more NO ｘ NO determined from the sensor ｘ The method according to claim 10, configured to adjust the flow rate of the reducing agent based on its content.

12. Compressing the output gas from the selective catalytic reduction system into a compressed output, Removing water from the aforementioned compression output, The gas separation membrane receives the compression output at its inlet. The method according to any one of claims 1 to 11, further comprising:

13. The method according to any one of claims 1 to 12, wherein the gas separation membrane includes a hollow fiber membrane.

14. The aforementioned reserve contains at least 85% by weight of N ２ The method according to any one of claims 1 to 13, comprising:

15. The aforementioned permeate contains at least 35% by weight of CO2 ２ The method according to any one of claims 1 to 14, comprising:

16. The aforementioned transparent material is N ２ CO ２ CO, CH ４ , C ２ H ６ H ２ O, Ar, O ２ , or NO ｘ The method according to any one of claims 1 to 15, comprising one or more of the above.

17. The method according to any one of claims 1 to 16, further comprising isolating the permeate within the ground injection site.

18. The aforementioned permeate CO ２ The method according to any one of claims 1 to 17, further comprising separating into a flow and a waste gas flow.

19. A system for obtaining nitrogen gas from flue gas, A selective catalytic reduction system, gas separation membrane and Equipped with, The aforementioned selective catalytic reduction system is The selective catalytic reduction system receives flue gas at its inlet, wherein the flue gas comprises one or more NOs. ｘ To have gas, The one or more NOs ｘ Gas to N ２ Reducing to gas and It is configured to do the following: The gas separation membrane is At the inlet of the gas separation membrane, the output gas from the selective catalytic reduction system is received, The output gas is separated into a retained substance and a permeate, wherein the retained substance is N ２ To have gas and A system configured to perform the following actions.

20. Equipped with an additional compressor, The compressor is, The compressor inlet receives the output gas from the selective catalytic reduction system, The output gas from the selective catalytic reduction system is compressed into a compressed output. The system according to claim 19, configured to perform the following:

21. Furthermore, equipped with a water removal system, The water removal system is The water removal system receives the compression output at its inlet, Removing water from the aforementioned compression output, The compression output from the outlet of the water removal system is transported to the inlet of the gas separation membrane. The system according to claim 20, configured to perform the following:

22. It also includes a burner / boiler system, The aforementioned burner / boiler system is To produce the aforementioned flue gas, Transporting the flue gas to the inlet of the selective catalytic reduction system A system according to any one of claims 19 to 21, configured to perform the following:

23. The aforementioned permeate CO ２ Separating into flow and exhaust gas flow is CO ２ The selective gas separation membrane receives the permeate at its inlet, The aforementioned CO ２ Using a selective gas separation membrane, the permeate is CO ２ Exhaust gas streams with poor reserves and CO ２ CO2, which is rich in permeable materials ２ The CO is separated into a flow. ２ The permeate rich in CO ２ To have gas and The method according to claim 18, including the method described in claim 18.

24. The aforementioned CO ２ The permeate rich in CO2 contains at least 92% by weight of CO2. ２ The method according to claim 23, comprising:

25. SO from the aforementioned flue gas ｘ The further includes removing SO from the flue gas. ｘ Removing the substance is a method according to any one of claims 1 to 18 or 23 to 24, comprising wet scrubbing or dry scrubbing.

26. The method according to any one of claims 1 to 18 or 23 to 25, further comprising removing dust from the flue gas, wherein removing dust from the flue gas comprises using one or more baghouses, one or more ceramic filters, or one or more electrostatic precipitators.

27. To remove water from the output gas from the selective catalytic reduction system, Compressing the aforementioned output gas into a compressed output, The gas separation membrane receives the compression output at its inlet. The method according to any one of claims 1 to 18 or 23 to 26, further comprising:

28. Furthermore, equipped with a water removal system, The water removal system is The inlet of the water removal system receives the output gas from the selective catalytic reduction system, To remove water from the output gas from the selective catalytic reduction system and produce a dried output gas. The system according to claim 19, configured to perform the following:

29. Equipped with an additional compressor, The compressor is, The inlet of the compressor receives the dried output gas, The aforementioned dried output gas is compressed into a compressed output, The compression output from the outlet of the compressor is transported to the inlet of the gas separation membrane. The system according to claim 28, configured to perform the following:

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