Method and system for photocatalytic oxidation of waste anesthetic gases

Abstract

Methods and systems for treating waste anesthetic gases are provided. A method includes flowing (710) an anesthetic off-gas into an inlet of a photocatalytic oxidation reactor while operating one or more ultraviolet lamps positioned inside the photocatalytic oxidation reactor to trigger oxide-catalyzed photolysis of the anesthetic off-gas and also forming acidic by-products during the process. The output of the photocatalytic oxidation reactor includes the acidic by-product and flows (722) to a neutralization reactor.

Description

Technical Field

[0001] Embodiments of the subject matter disclosed herein relate to systems and methods for photocatalytic oxidation of waste anesthetic gases. Background Art

[0002] During surgical procedures, a closed loop anesthesia circuit can be used to deliver a gas mixture including oxygen and an anesthetic to the patient and collect exhaled gases that include carbon dioxide in addition to excess anesthetic. The scavenging system can be configured to collect the exhaled carbon dioxide and excess anesthetic in a bag or canister to prevent exposure of medical personnel in the operating room to the anesthetic. The bag or canister can then be vented outside the building. However, anesthetics can include potent greenhouse gases such as desflurane, N 2 O, isoflurane, and sevoflurane, and direct venting to the atmosphere may not be desirable for environmental reasons. Summary of the invention

[0003] In one embodiment, a method for treating anesthetic waste gas includes flowing the anesthetic waste gas into an inlet of a photocatalytic oxidation reactor, operating one or more ultraviolet lamps of the photocatalytic oxidation reactor to trigger oxide-catalyzed photodecomposition of the anesthetic waste gas and form acidic byproducts, and flowing the output of the photocatalytic oxidation reactor including the acidic byproducts into a neutralization reactor.

[0004] It should be understood that the above brief description is provided to introduce in a simplified form selected concepts that are further described in the detailed description. It is not meant to identify key features or essential features of the claimed subject matter, the scope of which is uniquely defined by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The present invention will be better understood by reading the following description of non-limiting embodiments with reference to the accompanying drawings, in which:

[0006] Figure 1 is a diagram of a closed-loop anesthesia circuit coupled to a photocatalytic anesthesia waste gas treatment system;

[0007] Figure 2 is a graphic representation of the photocatalytic activity of wide bandgap semiconductor oxides;

[0008] Figure 3 is a diagram of a first embodiment of a photocatalytic anesthetic waste gas treatment system;

[0009] Figure 4 is a diagram of a second embodiment of a photocatalytic anesthetic waste gas treatment system;

[0010] Figure 5is a diagrammatic representation of an alternative embodiment of a photocatalytic anesthetic waste gas reactor;

[0011] Figure 6 yes Figure 5 A cross-sectional view of a photocatalytic anesthetic waste gas reactor;

[0012] Figure 7 is a flow chart of a method of operating a photocatalytic anesthetic waste gas reactor of a photocatalytic anesthetic waste gas treatment system;

[0013] Figure 8 is a flow chart of a method of operating a neutralization reactor of a photocatalytic anesthetic waste gas treatment system;

[0014] Fig. 9 yes Figure 8 a continuation of the method; and

[0015] Fig.10 is a flow chart of a method of operating a liquid replacement system fluidly coupled to a neutralization reactor. DETAILED DESCRIPTION

[0016] The following description relates to systems and methods for photocatalytic treatment of waste anesthetic gas. In an exemplary embodiment, a photocatalytic waste anesthetic gas (WAG) treatment system may be coupled to a Figure 1 Closed loop anesthesia circuit depicted. To prevent the collection and discharge of waste anesthetic gases into the environment, a photocatalytic WAG treatment system can chemically degrade WAG into products that are not potent greenhouse gases, which can then be released into the environment. In this context, the environment refers to the atmosphere outside the confines of a building (e.g., a hospital). Chemical degradation is known as photochemical oxidation and can be accomplished by the reaction of ultraviolet (UV) light with wide bandgap semiconductor oxides such as titanium dioxide (TiO 2 ) is driven by the interaction of superoxide and hydroxide radicals. The photochemical oxidation process is shown in Figure 2 A first embodiment of a photocatalytic WAG treatment system is shown in Figure 3 The photocatalytic anesthetic waste gas treatment system may include a system for compressing and accumulating the anesthetic waste gas output by the closed-loop anesthetic circuit, thereby ensuring the desired gas flow rate entering the photocatalytic oxidation (PCO) reactor. In some examples, the degradation of the anesthetic waste gas may produce acidic byproducts. Before being output from the photocatalytic anesthetic waste gas treatment system, the acidic byproducts may be directed to a neutralization reactor coupled to the photocatalytic anesthetic waste gas reactor. The photocatalytic WAG treatment system may also include sensors, such as UV sensors, pH sensors, and chemical sensors, which are configured to monitor and direct WAG and byproducts. In a second embodiment, as Figure 4 As shown, the PCO reactor and the neutralization reactor can be combined into a single hybrid reactor. The PCO reactor can be as follows Figure 3 The packed bed reactor depicted or Figure 5 to Figure 6 In some examples, the PCO reactor can degrade without producing acidic byproducts (e.g., N 2 O) of the anesthetic waste gas, and may not need to be coupled to a neutralization reactor. In an alternative embodiment, the PCO reactor can be coupled to a neutralization reactor and can be used to treat anesthetic waste gas that produces acidic byproducts. A method for operating a photocatalytic WAG reactor, a neutralization reactor, and a liquid replacement system coupled to a neutralization reactor is shown in Figures 7 to 9 middle.

[0017] Now go to Figure 1 , an exemplary embodiment of a closed-loop anesthesia circuit 100 coupled to a photocatalytic anesthetic waste gas treatment system 126 is shown. Fresh (e.g., not yet inhaled by a patient 107) anesthetic gas from an anesthesia machine can be introduced into the closed-loop anesthesia circuit 100 at a fresh gas inlet 102. The fresh anesthetic gas can flow through a carbon dioxide absorber cartridge 104 and through an inhalation check valve 106 to a patient 107. The inhalation check valve 106 can be configured to allow gas to flow to the patient, as indicated by arrow 108.

[0018] Additional compressed gas configured to drive the ventilator bellows 112 can enter the closed-loop anesthesia circuit 100 via the compressed gas inlet 110. The ventilator bellows 112 can help drive the patient 107's inspiration and exhalation, including the inhalation of anesthetic gases. The gas exhaled by the patient 107 can flow along the arrow 114 and flow through the exhalation check valve 116, flow through the carbon dioxide absorber cartridge 104 and flow back through the inspiration check valve 106. The exhaled gas can be a combination of carbon dioxide and anesthetic waste gas that is not absorbed by the patient's 107 lungs. Additionally or alternatively, the gas reservoir bag 118 can be used to manually drive the patient's 107 inspiration and exhalation. The valve 120 can be configured to switch between the closed-loop anesthesia circuit 100 being driven by the ventilator bellows 112 and being driven by the gas reservoir bag 118.

[0019] The ventilator exhaust valve 124 may be positioned in the flow path between the ventilator bellows 112 and the valve 120. When the valve 120 is positioned to drive the closed-loop anesthesia circuit 100 through the ventilator bellows 112, gas exhaled by the patient 107 may exit the closed-loop anesthesia circuit 100 through the ventilator exhaust via the ventilator exhaust valve 124. Similarly, an adjustable pressure limiting (APL) valve 122 may be positioned in the flow path between the reservoir bag 118 and the valve 120. When the valve 120 is positioned to drive the closed-loop anesthesia circuit 100 through the reservoir bag 118, gas exhaled by the patient 107 may exit the closed-loop anesthesia circuit 100 via the APL valve 122.

[0020] The outlets of the ventilator exhaust valve 124 and the APL valve 122 can each be coupled to an inlet of a photocatalytic anesthetic waste gas treatment system 126. The photocatalytic anesthetic waste gas treatment system 126 can be configured to react the anesthetic waste gas into benign components before disposal. In this way, the release of excess anesthetic gas into the environment can be avoided. In addition, the photocatalytic anesthetic waste gas treatment system 126 can eliminate the need for on-site storage and subsequent transportation of excess anesthetic gas, thereby reducing the time and cost associated with anesthetic waste gas treatment. It should be understood that a closed-loop anesthesia circuit is an example of a system that outputs anesthetic waste gas, but the photocatalytic anesthetic waste gas treatment system 126 can be coupled to the output of other systems that produce anesthetic waste gas.

[0021] A photocatalytic waste gas treatment system, such as the photocatalytic anesthetic waste gas treatment system 126, may include a photocatalytic oxidation reactor 128 that includes at least a UV light source and an oxide catalyst. In examples where the photocatalytic oxidation results in acidic gas byproducts, the photocatalytic anesthetic waste gas treatment system 126 may additionally include a neutralization reactor 130. In some examples, the photocatalytic oxidation reactor 128 and the neutralization reactor 130 may each be included in a hybrid photocatalytic oxidation / neutralization reactor. The oxide catalyst may be a wide bandgap semiconductor oxide configured to degrade anesthetic waste gas. In an exemplary embodiment, the wide bandgap semiconductor oxide may be titanium dioxide (TiO 2 Other wide bandgap semiconductor oxides (including but not limited to zinc oxide (ZnO) and cerium oxide (CeO- 2 )) are considered to be within the scope of this disclosure.

[0022] Now go to Figure 2 , shows the photocatalytic degradation of anesthetic waste gas by UV light in the presence of a wide bandgap semiconductor oxide. UV light 202 can be directed to a wide bandgap semiconductor oxide 204. Figure 2 The electronic structure of a wide bandgap semiconductor oxide 204 is schematically shown in the diagram 200 of FIG. The electronic structure includes a conduction band 206 and a valence band 208. The energy difference between the lowest electronic energy level of the conduction band 206 and the highest electronic energy level of the valence band 208 is the band gap (E g ) energy. UV light 202 may correspond to energy equal to or greater than the band gap energy. Thus, wide band gap semiconductor oxide 204 may absorb UV light 202 and use the energy to elevate electrons 216 from valence band 208 to conduction band 206, as indicated by arrow 210, thereby leaving holes 218 in valence band 208.

[0023] As indicated by arrows 212 and 214, respectively, electrons 216 and holes 218 may both travel to the surface of wide bandgap semiconductor 204. Electrons 216 may react with oxygen, as indicated by arrow 212, to produce superoxide radicals (O 2- The holes 218 can react with water to generate hydroxide radicals ( · OH). Superoxide and hydroxide radicals are highly energetic and can readily react with waste anesthetic gases to form carbon dioxide (CO 2 ), water (H 2 O) and other by-product gases. In some examples, the by-product gases may include acidic by-product gases, such as hydrofluoric acid (HF) gas and hydrochloric acid (HCl) gas.

[0024] Wide bandgap semiconductor oxides and UV light can be combined into a photocatalytic anesthetic waste gas treatment system. A first embodiment of a photocatalytic anesthetic waste gas treatment system 300 is shown in Figure 3 Solid lines connecting components of the photocatalytic anesthetic waste gas treatment system 300 indicate fluid paths (e.g., fluid couplings), while dashed lines indicate communication couplings. The communication couplings of the components may be wired or wireless. The photocatalytic anesthetic waste gas treatment system 300 may be Figure 1 In some examples, the anesthetic waste gas treatment system 300 can be coupled to the outlet of a closed-loop anesthesia circuit, such as Figure 1 shown.

[0025] Anesthetic waste gas may enter the photocatalytic anesthetic waste gas treatment system 300 via the anesthetic waste gas inlet 302. In some examples, a flow sensor 304 may be optionally positioned in the flow path of the anesthetic waste gas downstream of the anesthetic waste gas inlet 302. The flow sensor 304 may be configured to sense the flow rate of the anesthetic waste gas entering the anesthetic waste gas treatment system 300. The flow sensor 304 may be communicatively coupled to the controller 306. In an alternative example, the controller 306 may be communicatively coupled to a flow sensor of an anesthesia circuit (e.g., a closed-loop anesthesia circuit 100), which is fluidly coupled to the photocatalytic anesthetic waste gas treatment system 300 and is configured to transmit the flow rate of the anesthetic waste gas to the photocatalytic anesthetic waste gas treatment system 300.

[0026] The controller 306 may receive input data from the various sensors described herein, process the input data, and trigger various actuators in response to the processed input data based on executable instructions or codes programmed therein corresponding to one or more routines. The controller 306 may include a non-volatile memory configured to store instructions and a processor configured to execute instructions. The controller 306 may be further coupled to a display 308 and a user interface 310. In some examples, the user interface 310 and the display 308 may be mobile devices communicatively coupled to the controller 306.

[0027] The anesthetic waste gas may flow to an inlet gas diverter valve 312. The inlet gas diverter valve 312 may be configured to direct the anesthetic waste gas to a gas accumulator 313, a photocatalytic oxidation reactor 316, or an outlet 318 of the photocatalytic anesthetic waste gas treatment system 300. The inlet gas diverter valve 312 may be communicatively coupled to the controller 306 and may receive instructions to divert the gas based on input from a sensor coupled to the controller 306. For example, in response to a sensed flow rate of the anesthetic waste gas downstream of the inlet gas diverter valve 312 (e.g., from the flow sensor 304) being below a threshold flow rate, the inlet gas diverter valve 312 may be configured to direct the anesthetic waste gas to the gas accumulator 313. The threshold flow rate may be a flow rate below which the anesthetic waste gas may not be effectively or evenly distributed through the photocatalytic oxidation reactor 316. As an example, the threshold flow rate may be 2.0 standard liters per minute (slpm). In response to a sensed flow rate above a threshold flow rate, the inlet gas diverter valve 312 may be configured to direct the anesthetic waste gas directly to the photocatalytic oxidation reactor 316 , thereby bypassing the compressor 314 .

[0028] The gas accumulator 313 may include a compressor 314 fluidly coupled to an accumulation tank 320. The accumulation tank 320 may be a container, such as a rigid container, configured to receive the anesthetic waste gas output by the compressor 314. The accumulation tank 320 may include a pressure sensor 322, which is communicatively coupled to the controller 306 and configured to output the gas pressure inside the accumulation tank 320. The accumulator output valve 324 may be positioned downstream of the accumulator tank 320 and in the fluid path between the accumulator tank 320 and the photocatalytic oxidation reactor 316. The accumulator output valve 324 may be communicatively coupled to the controller 306. In one example, the controller 306 may adjust the accumulator output valve 324 from a closed position to an open position in response to the pressure in the accumulation tank 320 reported by the pressure sensor 322 being higher than a threshold pressure. In this manner, when the flow rate of the waste anesthetic gas input into the photocatalytic waste anesthetic gas treatment system 300 is below a threshold flow rate, the accumulation tank 320 can store the waste anesthetic gas and build up pressure.

[0029] The anesthetic waste gas may be directed to a photocatalytic oxidation reactor 316, wherein the ... Figure 2 The photocatalytic oxidation generates photocatalytic decomposition of the anesthetic waste gas. The photocatalytic oxidation reactor 316 may include a distributor 326, a 2 ) oxide-coated porous ceramic pellets 328, a UV light system 330, and an ultraviolet sensor 332. In one example, the photocatalytic oxidation reactor 316 can be a packed bed photocatalytic oxidation reactor.

[0030] The distributor 326 can be directly coupled to the inlet of the PCO reactor 316 and can be configured to evenly distribute the anesthetic waste gas throughout the volume of the photocatalytic oxidation reactor 316. In this way, tunneling of the anesthetic waste gas through the photocatalytic oxidation reactor 316 can be prevented. In some examples, the distributor 326 can be a glass frit.

[0031] The oxide-coated porous ceramic pellets 328 can be uniformly coated with a wide bandgap semiconductor oxide. The pores of the oxide-coated porous ceramic pellets 328 can be configured to increase the exposed surface area, and the oxide coating of the oxide-coated porous ceramic pellets 328 includes a coating on the inner surface of the pores. In this way, the anesthetic waste gas can pass through the surface of the porous ceramic pellets and through its pores and react with free radical species (e.g., superoxide and hydroxide radicals) generated by the reaction of the wide bandgap semiconductor oxide with the UV light emitted by the UV light system 330.

[0032] The UV light system 330 may include a power source 330a and a UV lamp 330b. In one example, the UV light system 330 may include two UV lamps 330b, however other numbers of UV lamps 330b are also considered within the scope of the present disclosure. In one example, the UV lamp 330b may be a mercury lamp. In an alternative example, the UV lamp 330b may be a light emitting diode (LED). The wavelength range emitted by the UV light system 300 may be selected based on the band gap energy of the wide band gap semiconductor oxide. For example, if the wide band gap semiconductor oxide is TiO 2 , the UV lamp may be selected to emit a wavelength of at least 380nm or less (e.g., higher energy). In some examples, the range of wavelengths may be between 260nm and 350nm. UV lamp 330b may be positioned inside the housing of PCO reactor 316. UV lamp 330b may be configured to excite the wide bandgap semiconductor oxide coating of oxide-coated porous ceramic granules 328. Power supply 330a may be communicatively coupled to controller 306. UV sensor 332 may be configured to output a signal proportional to the intensity of UV light emitted by UV light system 330. In response to a UV light intensity below a threshold intensity, controller 306 may include an instruction to increase the power output of power supply 330a to increase the UV light intensity. If the power output of power supply 330a is already at maximum power output and the UV light intensity is below a threshold intensity, controller 306 may include an instruction to output a visual or audible alarm to prompt a user to replace UV lamp 330b. In one example, a visual alarm may be displayed at display 308. In addition to displaying the alarm, the controller 306 may also actuate the inlet gas diverter valve 312 to direct the anesthetic waste gas directly to the outlet 318. In this manner, breakthrough of the anesthetic waste gas may be avoided in the event that the UV lamp 330b needs to be replaced.

[0033] The output of the photocatalytic oxidation reactor 316 may be directed to the inlet of a byproduct chemical sensor 354. The output of the photocatalytic oxidation reactor 316 may be a decomposition gas byproduct of the anesthetic gas being degraded by free radical species. The decomposition gas byproducts may include acidic gas byproducts, including hydrogen fluoride and hydrogen chloride gases, among other gases. The byproduct chemical sensor 354 may be communicatively coupled to the controller 306 and configured to determine the concentration of chemical byproducts output by the photocatalytic oxidation reactor 316. In one example, the byproduct chemical sensor 354 may include an array of chemical sensors, each chemical sensor being configured to selectively and quantitatively detect a chemical component or class of chemical components of the decomposition gas byproducts. In one example, the byproduct chemical sensor 354 may be an infrared sensor.

[0034] The diverter valve 356 may be positioned downstream of the byproduct chemical sensor 354 and upstream of the neutralization reactor 334. The diverter valve 356 may be communicatively coupled to the controller 306. In response to the byproduct chemical sensor 354 measuring that the concentration of the decomposition gas byproduct is below a threshold concentration, the controller 306 may adjust the diverter valve 356 to direct the gas output from the PCO reactor 316 back to the input of the PCO reactor 316. The threshold concentration may be determined by the controller based on a known composition of the anesthetic waste gas and a threshold flow rate and / or a threshold pressure. In response to the byproduct chemical sensor 354 measuring that the concentration of the decomposition gas byproduct is greater than or equal to the threshold concentration, the controller 306 may adjust the diverter valve 356 to direct the gas output from the PCO reactor 316 to the neutralization reactor 334. In some examples, the controller 306 may also adjust the diverter valve 356 to bypass the neutralization reactor 334 and direct the output of the PCO reactor 316 to the outlet 318.

[0035] Hydrogen fluoride and hydrogen chloride are acidic, corrosive gases that may be included in the decomposition gas byproducts. For this reason, the neutralization reactor 334 is configured to neutralize acid gases (e.g., acidic substances), such as hydrogen fluoride and hydrogen chloride, to prevent acid gas exposure to humans, non-acid resistant equipment, and the environment.

[0036] The neutralization reactor 334 may include a cooling system 336, a distribution system 338, a pH sensor 340, and a replaceable cartridge 342. The replaceable cartridge 342 may include a neutralization solution 344. In some examples, the temperature sensor 341 may share contact with the outer surface of the replaceable cartridge 342 and be configured to determine the temperature of the cartridge housing. Before operation of the photocatalytic anesthetic waste gas treatment system 300, the neutralization solution 344 may be an alkaline aqueous solution. As an example, the neutralization solution 344 may be a solution of one or more weak bases such as calcium hydroxide or sodium bicarbonate. The gaseous byproducts from the photocatalytic oxidation reactor 316 may be directed to the neutralization solution 344 via the distribution system 338. The distribution system 338 may include a jet filter and / or a magnetic stirrer positioned at the inlet of the replaceable cartridge 342 and configured to effectively dissolve the gaseous byproducts into the neutralization solution 344.

[0037] When dissolved in the neutralization solution 344, the acidic gaseous byproducts (e.g., HF and HCl gases) can react with the alkaline substances of the neutralization solution 344 to produce water and neutral salts. In some examples, the neutral salts can be insoluble in water and can be accumulated in the replaceable box 342 as a precipitate. Over time, the acidic gaseous byproducts can deplete the alkaline substances, and the pH of the neutralization solution 344 can be reduced from an alkaline pH to a neutral / acidic pH. For this reason, the pH sensor 340 is communicatively coupled to the controller 306 and can be configured to monitor the pH of the neutralization solution 344. In response to a pH lower than a threshold pH, the controller 306 can (e.g., via a display 308) remind the user to replace the replaceable box 342 with a new box. The threshold pH can be greater than 7.0. In one example, the threshold pH can be equal to 7.5. The new box can include a fresh alkaline solution at an alkaline pH. In some examples, in response to a pH below a neutral pH (e.g., pH 7.0), the controller 306 may actuate the inlet gas diverter valve 312 to direct the anesthetic waste gas directly to the outlet 318. In one example, the outlet 318 may be fluidly coupled to an anesthetic gas scavenging system. The anesthetic gas scavenging system may capture or direct the gas to be released to the environment outside (e.g., the environment outside the hospital building). In this way, when the neutralization reactor 334 cannot neutralize the acidic byproducts, photocatalytic reactions that produce acidic byproducts can be avoided. In some examples, the anesthetic gas scavenging system may include a vacuum that is configured to place the anesthetic gas scavenging system and the photocatalytic anesthetic waste gas treatment system 300 under negative pressure.

[0038] The neutralization reaction between the acidic gaseous byproduct and the alkaline substance can be an exothermic reaction. For this reason, the cooling system 336 can include a jacket circumferentially surrounding the replaceable box 342. In one example, the cooling system 336 can be a solid cooling system, such as a piezoelectric cooler with a cold side that is in contact with the replaceable box 342 face sharing. In an alternative example, the cooling system 336 can be fluidically coupled to a circulating cooler, which is configured to output a cold fluid to the inlet of the cooling jacket and receive a warm fluid from the outlet of the cooling jacket. In an additional embodiment, the cooling system 336 can be an immersion cooling system positioned to directly share contact with the fluid in the cooling jacket or directly share contact with the neutralization solution 344. In some examples, the cooling system 336 may include a temperature sensor configured to monitor the temperature of the coolant. The cooling system 336 can be communicatively coupled to the controller 306. The controller 306 can control the target temperature of the cooling system 336.

[0039] The output of the neutralization reactor 334 may include non-acid gases, including water vapor, and in some examples, CO may be produced as a result of the neutralization reaction. 2 . In some examples, at least a portion of the fluid path 348 that neutralizes the output of the reactor 334 can be formed of a selectively permeable material. The selectively permeable material can be configured to allow water vapor 350 to easily pass through the material while other gases (such as oxygen and carbon dioxide) are retained therein. As an example, the selectively permeable material can be a sulfonated tetrafluoroethylene-based fluoropolymer. In some examples, waste heat from the cooling system 336 can be directed to the fluid path 348. In this way, the relative humidity of the air surrounding the fluid path 348 can be reduced and the driving force (e.g., velocity) of the water vapor 350 leaving the fluid path 348 can be increased.

[0040] The chemical sensor 352 may be positioned downstream of the neutralization reactor 334 and upstream of the outlet 318. The chemical sensor 352 may be configured to sense the level (e.g., concentration) of the penetration gas flowing out of the neutralization reactor 334. The penetration gas may include penetration acidic gases (e.g., HF and HCl) and / or penetration anesthetic waste gases present in the gas output from the neutralization reactor 334. In one example, the chemical sensor 352 may be an array of chemical sensors, each of which is configured to sense the gas of interest. In some examples, the chemical sensor 352 may include one or more infrared (IR) sensors. In an alternative example, the chemical sensor 352 may include one or more of a photoionization sensor, an electrochemical sensor, or other types of sensors configured to selectively and quantitatively monitor the presence of hazardous gases. The chemical sensor 352 may be communicatively coupled to the controller 306. The controller 306 may include instructions for generating an alarm when the level of acidic gas and / or anesthetic waste gas is above a threshold level. Additionally, the controller 306 may actuate the inlet gas diverter valve 312 to direct the waste anesthetic gas directly to the outlet 318 in response to the level of acid gas and / or waste anesthetic gas being above a threshold level.

[0041] Now go to Figure 4 , shows an alternative embodiment of a photocatalytic anesthetic waste gas treatment system 400. The photocatalytic anesthetic waste gas treatment system 400 may include a hybrid PCO / neutralization reactor 402, instead of Figure 3 The PCO reactor 316 and the neutralization reactor 334 of the embodiment of the invention may include similar components to the photocatalytic anesthetic waste gas treatment system 300. Similar components are numbered in the same manner and may not be reintroduced.

[0042] In some examples, similar to the anesthetic waste gas treatment system 300, the anesthetic waste gas treatment system 400 may include an inlet gas diverter valve 312 and optionally a gas accumulator 313. In alternative examples, the hybrid PCO / neutralization 402 reactor may be configured to effectively react to a wide range of input gas flow rates. In such examples, the anesthetic waste gas treatment system 400 may not include a gas accumulator 313. Therefore, in such examples, the inlet gas diverter valve 312 may be configured to direct the anesthetic waste gas to the hybrid PCO / neutralization reactor 402 or the outlet 318.

[0043] The anesthetic waste gas may be directed to the reaction box 414 via the distribution system 338. The reaction box 414 may include a neutralizing solution 344 and suspended wide bandgap semiconductor particles 404. In one example, the diameter size of the wide bandgap semiconductor oxide particles may range between 12 nm and 29 nm. In some examples, the diameter of the wide bandgap semiconductor oxide particles may be up to 29 nm. In some embodiments, the wide bandgap semiconductor oxide particles may be roughly spherical, but other shapes of particles, such as rods or ellipsoids, are also contemplated. The photocatalytic rate may be inversely proportional to the size of the wide bandgap semiconductor oxide. As the size of the wide bandgap semiconductor oxide particles increases, the photocatalytic rate constant may decrease exponentially. Free radicals may be generated by exciting the wide bandgap semiconductor particles 404 with UV light from the UV lamp 330b, and may react with the anesthetic waste gas to degrade the anesthetic waste gas, as described above with respect to Figure 2 In addition, the components of the anesthetic waste gas can be degraded by direct reaction with the alkaline substance of the neutralizing solution 344. When the alkaline substance is sodium bicarbonate and the anesthetic waste gas includes compound A (CF 2 =C(CF 3 )-O-CH 2 F), compound A may not dissolve in the sodium bicarbonate solution and thus may form a precipitate. In an alternative example where the alkaline substance is sodium bicarbonate and the anesthetic waste gas includes pentafluoropropanol, pentafluoropropanol may react exothermically with the sodium bicarbonate to form trifluoromethyl acetate and carbon dioxide. The neutralization reaction may also occur in the neutralization solution 344, because the acidic byproducts may react directly with the alkaline substance after being formed near the surface of the wide bandgap semiconductor particles 404.

[0044] In some examples, the neutralization solution 344 may need to be replaced before replacing the UV light system 330. In such examples, the liquid replacement system 416 may be fluidly coupled to the reaction box 414. In some examples, the liquid replacement system 416 may be fluidly coupled to the PCO reactor, such as Figure 3The PCO reactor 316 of the present invention. The liquid replacement system 416 may include a self-sealing fluid cartridge 412, a bidirectional pump 410, and a liquid shutoff valve 408. The self-sealing fluid cartridge 412 may include a fresh neutralization solution. The volume of the fresh neutralization solution included in the self-sealing fluid cartridge 412 may be equal to the volume of the neutralization solution 344 included in the reaction cartridge 414. In some examples, the fresh neutralization solution may include replacement of the wide bandgap semiconductor particles 404. In an alternative example, the liquid shutoff valve may be configured to selectively allow an aqueous solution to pass while forcing the wide bandgap semiconductor particles to remain in the reaction cartridge 414. In such examples, the fresh neutralization solution may not include the wide bandgap semiconductor particles 404. In some examples, the self-sealing fluid cartridge 412 may also include an empty volume configured to receive a used neutralization solution. The self-sealing fluid cartridge 412 may be fluidly coupled to the bidirectional pump 410. The liquid shutoff valve 408 can be positioned in the fluid path between the two-way pump 410 and the reaction cartridge 414, and can be configured to control the flow of liquid into and out of the reaction cartridge 414. The liquid shutoff valve 408 and the two-way pump 410 can each be communicatively coupled to the controller 306. The controller 306 can include instructions to actuate the two-way pump and the liquid shutoff valve 408 to flow used neutralization solution from the reaction cartridge 414 to the empty volume of the self-sealing fluid cartridge 412, and to actuate the two-way pump 410 and the liquid shutoff valve 408 to flow fresh neutralization solution from the self-sealing fluid cartridge 412 into the reaction cartridge 414. When filled with used neutralization solution and out of fresh neutralization solution, the self-sealing fluid cartridge 412 can be configured to be removed from the liquid replacement system 416 for disposal.

[0045] In some examples, condensation trap 418 may be positioned downstream of chemical sensor 352 and upstream of outlet 318. The fluid path of condensation trap 418 may be cooled to a temperature of -80°C or lower. In some examples, the temperature of condensation trap 418 may be maintained above -189°C to prevent O 2 In this way, at least some of the fluorinated compounds that are not degraded to HF by the photocatalytic oxidation reactor can be captured in the liquid trap 420 for later disposal. In one example, the fluorinated compound can be fluoromethyl-2,2-difluoro-1-(hydroxymethylpropane). The remaining gas 422 (such as CO 2 and O 2 ) may continue through outlet 318. In some examples, condensation trap 418 may be included in Figure 3 of the anesthetic waste gas treatment system 300 and is positioned downstream of the chemical sensor 352 and upstream of the outlet 318.

[0046] In some examples, when high throughput is required, an alternative embodiment 500 of the photocatalytic oxidation reactor may be included in a photocatalytic anesthetic waste gas treatment system, such as replacing the photocatalytic oxidation reactor 316 of the photocatalytic anesthetic waste gas treatment system 300. In some examples, the alternative embodiment 500 may be configured to treat non-halogenated anesthetic waste gas, such as nitrous oxide. In such examples, the byproducts of the oxidation of the anesthetic waste gas may not be acidic, and a neutralization reactor may not be included in the photocatalytic anesthetic waste gas treatment system.

[0047] Alternative embodiment 500 Figure 5 and Figure 6 Shown in. Figure 5 A diagram showing a side view of an alternative embodiment 500 is shown, and Figure 6 A cross-sectional view of an alternative embodiment 500 is shown. A reference axis 502 including an x-axis, a y-axis, and a z-axis is provided for Figure 5 and Figure 6 Comparison between. Figure 5 and Figure 6 Can include and Figure 3 and Figure 4 The photocatalytic anesthetic waste gas treatment systems 300 and 400 have similar components. Similar components will be marked as the same and may not be reintroduced.

[0048] An alternative embodiment 500 of the photocatalytic oxidation reactor may include a UV lamp 330b. In one example, the UV lamp 330b may be shaped as a cylinder. The y-axis may be an axial axis relative to the UV lamp 330b. The ultraviolet transparent tube 504 may be placed in contact with the UV lamp 330b surface, or placed at a threshold distance from the surface of the outer surface of the UV lamp 330b. The UV transparent tube 504 may be a hollow tube including an internal lumen, and the anesthetic waste gas may flow through the lumen of the UV transparent tube 504, through the first end, as indicated by arrow 506, and out of the second end, the second end is away from the first end, as indicated by arrow 508. The UV transparent tube 504 may be formed of a UV transparent material. For example, the UV transparent tube 504 may be formed of quartz. In one example, the UV transparent tube 504 may include a single lumen that is anti-axially wound around the axial length of the UV lamp 330b.

[0049] The lumen 603 of the UV transparent tube 504 is Figure 6 The cross-sectional view is shown in more detail. Figure 6 An alternative embodiment of the UV transparent tube 504 is shown, including multiple UV transparent tubes 504 arranged coaxially with the UV lamp 330b. In some examples, the UV transparent tubes can be arranged coaxially and spirally wound around the UV lamp 330b along the y-axis. The cross-section of the UV transparent tube 504 is Figure 6 The coaxial arrangement and Figure 5The reverse axial and spiral arrangements can be similar.

[0050] The inner surface 602 of the UV transparent tube 504 may be coated with a wide bandgap semiconductor oxide (e.g., TiO 2 ). In this way, UV light 604 can be radiated from the UV lamp 330b through the UV transparent tube 504 and excite the wide bandgap semiconductor coating, thereby emitting free radical species to react with the anesthetic waste gas and degrade the anesthetic waste gas. In some examples, silver particles can be deposited on the wide bandgap semiconductor coating. The silver particles can enhance the electron / hole separation, thereby improving the efficiency of the wide bandgap semiconductor to produce free radicals. In addition, the ultraviolet transmission fiber 606 can be concentrically positioned in the lumen 603 of the UV transparent tube 504. In some examples, the first axial end of the UV transmission fiber 606 can be coupled to an additional UV light source, such as a UV LED. The UV transmission fiber 606 can be configured to transmit UV light from the first axial end of the UV transmission fiber 606 to the second axial end of the UV transmission fiber 606 by total internal reflection. In addition, the UV transmission fiber 606 can be configured to reflect the UV light 608 out of the UV transmission fiber 606 toward the inner surface 602 of the UV transparent tube 504. Additionally or alternatively, the UV transmission fiber 606 can reflect the UV light emitted by the UV lamp 330b. In this manner, the interaction between UV light and the wide bandgap semiconductor coated inner surface 602 may be increased, thereby increasing the rate and concentration of free radical formation and increasing the subsequent photocatalytic degradation rate of anesthetic waste gases.

[0051] Now go to Figure 7 , a flow chart of a method 700 for operating a photocatalytic oxidation reactor of a photocatalytic anesthetic waste gas treatment system is shown. Instructions for performing method 700 and the remaining methods included herein may be executed by a controller (e.g., controller 306) based on executable instructions stored in a non-volatile memory of the controller and in combination with sensors of the photocatalytic anesthetic waste gas system (such as those described above with reference to Figure 3 The controller may use an actuator of the photocatalytic anesthetic waste gas system to adjust the flow rate of the anesthetic waste gas according to the method described below. The photocatalytic oxidation reactor of method 700 may be a packed bed reactor (such as Figure 3 Photocatalytic oxidation reactor 316, Figure 4 A mixed PCO / neutralization reactor) or a spiral flow reactor such as Figure 5 and Figure 6 An alternative embodiment 500 is shown in FIG.

[0052] At 702, method 700 includes measuring an inlet waste anesthetic gas (WAG) flow rate. In some examples, the WAG flow rate can be measured by an inlet flow sensor such as Figure 3In an alternative embodiment, the controller may be communicatively coupled to an anesthesia system that is fluidly coupled to an inlet of the waste anesthesia gas treatment system, and measuring the WAG flow rate may include receiving the flow rate from a sensor of the anesthesia system.

[0053] At 704, method 700 includes determining whether the inlet WAG flow rate is less than a threshold flow rate. The threshold flow rate may be a flow rate below which the anesthetic waste gas may not be effectively processed by the photocatalytic oxidation reactor (PCO). The threshold flow rate may be based on the configuration of the PCO reactor. For example, a PCO reactor configured as a packed bed reactor (e.g., Figure 3 The PCO reactor 316) may have a different threshold flow rate than the mixing PCO / neutralization reactor 402 or the flow through the PCO reactor 500. In some examples, the threshold flow rate may depend on the desired back pressure for operation of the photocatalytic oxidation reactor.

[0054] If at 704, method 700 determines that the inlet WAG flow rate is less than the threshold flow rate (YES), method 700 proceeds to 706 and includes directing the WAG to the compressor. The compressor may be similar to Figure 3 The compressor 314 can force the WAG into an accumulation tank, such as Figure 3 320 of the accumulation tank. Method 700 then continues to 708 and determines whether the pressure in the accumulation tank is greater than a threshold pressure. The pressure in the accumulation tank can be determined by a pressure sensor that is fluidly coupled to the accumulator and communicatively coupled to the controller. The threshold pressure can be a pressure associated with the ability of the WAG to flow from the accumulation tank to the PCO reactor at a flow rate greater than a threshold flow rate. If the pressure in the accumulator is not greater than the threshold pressure (No), method 700 returns to 706 and continues to direct the WAG to the compressor. If the pressure is greater than the threshold pressure (Yes), method 700 continues to 710 and includes directing the WAG to the inlet of the PCO reactor. If at 704, method 700 determines that the inlet WAG flow rate is greater than or equal to the threshold flow rate (No), method 700 also continues to 710.

[0055] At 712, method 700 includes measuring a concentration of gaseous byproducts at an outlet of the PCO reactor. The gaseous byproducts may be measured by a chemical sensor positioned at the outlet of the PCO reactor. At 714, method 700 determines whether the measured concentration of the gaseous byproducts is greater than or equal to a threshold concentration. The threshold concentration may correspond to an expected concentration of the gaseous byproducts based on the WAG input and assuming that the WAG is substantially fully (e.g., within 5%) degraded. The threshold concentration may be determined by a controller based on a threshold flow rate and a threshold pressure. If at 714, method 700 determines that the gaseous byproducts are greater than or equal to the threshold concentration (yes), method 700 proceeds to 722 and includes directing the gaseous byproducts to a neutralization reactor. Methods for flowing gaseous byproducts through a neutralization reactor are described below with respect to Figure 8 Further description.

[0056] If at 714, method 700 determines that the measured concentration of the gaseous byproduct is less than the threshold concentration (NO), method 700 proceeds to 716 and includes increasing power (e.g., operating power) to the UV light system of the PCO reactor. The UV light system may be similar to Figure 3 and Figure 4 UV light system 330. Increasing the power of the UV light system can increase the number of photons emitted from the UV lamp of the UV light system. Method 700 continues to 718 and determines whether an increase in UV intensity in the PCO reactor corresponding to an increase in UV power is observed. The UV intensity in the PCO reactor can be determined by a UV sensor positioned within the PCO reactor and communicatively coupled to the controller. If at 718, method 700 determines that the UV intensity does correspond to the increased power (yes), method 700 returns to 710 and guides the gas from the outlet of the PCO reactor back to the inlet of the PCO reactor. If at 718, method 700 determines that the UV intensity does not correspond to the increased power (no), method 700 proceeds to 720 and includes generating an alarm. The alarm can be generated at a display communicatively coupled to the controller. Additionally or alternatively, the alarm may include an audio signal, such as an alarm or a chime. The alarm may prompt the user to guide the WAG to the outlet of the anesthetic waste gas treatment system and replace the UV lamp. Additionally or alternatively, the alarm may prompt the user to adjust the threshold flow rate and threshold pressure. Method 700 may proceed to 710 and continue to recycle WAG back to the inlet of the PCO reactor. Method 700 may proceed in this manner until the gas byproduct concentration determined at step 714 is greater than or equal to the threshold concentration and the gas byproduct is directed to the neutralization reactor at 722. Method 700 returns.

[0057] Now go to Figure 8 , showing a method for operating an anesthetic waste gas treatment system (such as Figure 3Flowchart of method 800 for a neutralization reactor of an anesthetic waste gas treatment system 300 of the present invention. In some examples, method 800 may continue from method 700 after method 700 determines that the anesthetic waste gas is sufficiently degraded at the output of the PCO reactor. In some examples, method 800 may be optional and may be omitted if the degradation of the anesthetic waste gas is not expected to produce acid gas byproducts. In some examples, the neutralization reactor may be a hybrid PCO / neutralization reactor, such as Figure 4 A mixed PCO / neutralization reactor 402.

[0058] At 802, method 800 determines whether the temperature of the neutralization box is less than a threshold temperature. The temperature of the neutralization box can be determined by a temperature sensor that shares contact with an outer surface of the neutralization box and is communicatively coupled to a controller. The neutralization box can be a replaceable box (e.g., Figure 2 Replaceable cartridge 342) or Figure 4 The threshold temperature may be a temperature above which degradation of components of the neutralization system may occur. In one example, the threshold temperature may be 50° C. If method 800 determines that the cartridge housing temperature is greater than the threshold temperature (NO), method 800 proceeds to Fig. 9 822 shown and includes increasing cooling. Increasing cooling may include increasing the power of the cooling system used to cool the neutralization box. Increasing cooling may include adding to the cooling system (e.g., Figure 3 336). Additionally, in some examples, increasing cooling may include, at 826, lowering the set point temperature of the cooling system to a cooler temperature. Additionally, increasing cooling may include, at 828, increasing the agitation speed of the dispensing system of the neutralization reactor. Increasing the agitation speed may increase contact between the bulk of the neutralizing solution and the cool elements of the cooling system, thereby increasing cooling. Method 800 continues to 830 and determines whether the cooling system is at maximum power. In some examples, if the cooling system is set to the coldest possible temperature, the cooling system may be at maximum power. If, at 830, method 800 determines that the cooling system is not at maximum power (NO), method 800 returns to Figure 8 802 shown and again determine whether the temperature of the neutralization box is less than the threshold temperature. If at 830, method 800 determines that the cooling system is at maximum power (yes), then method 800 continues to 818, as Figure 8 as shown, and includes directing gaseous byproducts away from neutralization, as further described below.

[0059] If at 802, method 800 determines that the neutralization box temperature is less than the threshold temperature (yes), then method 800 proceeds to 804 and includes measuring the pH of the neutralization solution. The pH of the neutralization solution can be measured using a pH sensor positioned in the neutralization solution and coupled to the controller with communication. When the neutralization system is in operation, the pH of the neutralization increases as the alkaline substance of the neutralization solution is exhausted. In some examples, the pH of the neutralization solution can be continuously monitored. At 806, method 800 determines whether the pH of the neutralization solution (e.g., monitored pH) is less than or equal to the threshold pH. The threshold pH may be higher than pH 7.0. In one example, the threshold pH may be 7.5. If method 800 determines that the pH of the neutralization solution is not less than or equal to the threshold pH (no), then method 800 returns to 804 and continues to monitor the pH of the solution. If method 800 determines that the pH of the neutralization solution is less than or equal to the threshold pH (yes), then method 800 proceeds to 808 and includes indicating that the user will soon change the box (e.g., neutralization box). Instructing the user to replace the neutralization cartridge soon may include generating an audio and / or visual alert. In one example, a visual alert may be generated at a display. In some examples, at 809, method 800 includes automatically replacing the neutralization solution in the cartridge. A liquid replacement system (such as Figure 4 The liquid replacement system 416 can be configured to automatically replace the used neutralization solution (e.g., pH ≤ 7.5) with fresh neutralization solution. Fig.10 The operation of the fluid replacement system is further described.

[0060] At 810, method 800 determines whether the pH of the neutralization solution is equal to 7.0. If the pH of the neutralization solution is not equal to 7.0 (no), method 800 returns to 804 and continues to measure the pH of the neutralization solution. If the pH of the neutralization solution is equal to 7.0 (yes), method 800 continues to 812 and includes measuring the composition of the neutralization reactor output. The composition of the neutralization reactor output can be measured by a chemical sensor (e.g., chemical sensor 352) positioned downstream of the neutralization reactor outlet and upstream of the anesthetic waste gas treatment system outlet. The chemical sensor can be configured to detect the concentration of acidic byproduct gases (e.g., HF and HCl) and the concentration of anesthetic waste gases.

[0061] At 814, method 800 determines whether WAG or acid gas byproducts are above a breakthrough concentration. In some examples, the breakthrough concentration may be a value greater than zero that corresponds to the lowest sensitivity of the chemical sensor. In other words, the breakthrough concentration may be the lowest concentration reported by the chemical sensor that is considered a true and reliable measurement. In an alternative example, the breakthrough concentration is equal to the threshold exposure limit. If method 800 determines that WAG or acid gas byproducts are not above the breakthrough concentration (NO), method 800 proceeds to 816 and includes maintaining the flow of WAG to the PCO and the flow of gas byproducts from the PCO to the neutralization reactor. Method 800 returns.

[0062] If method 800 determines that WAG or acid gas byproducts are above the breakthrough concentration, method 800 proceeds to 818 and includes generating an alarm and directing gas byproducts away from the outlet of the neutralization reactor and the anesthetic waste gas treatment system. The gas byproducts can be directed by actuating a valve positioned in the flow path between the outlet of the PCO and the neutralization reactor. Generating an alarm can include generating an audio or visual alarm. The visual alarm can be displayed at the display. The alarm can convey to the user that breakthrough has occurred and WAG and byproduct gases are being directed to the outlet. At 820, method 800 includes directing WAG directly to the outlet of the photocatalytic anesthetic waste gas treatment system. Directing WAG directly to the outlet of the photocatalytic anesthetic waste gas may include actuating an inlet gas valve positioned upstream of the PCO reactor. In this way, when there is a danger that WAG or acid gas byproducts may be discharged from the anesthetic waste gas treatment system into a closed area, WAG and acid gas byproducts can be directed to the outside of the closed area (e.g., an operating room) and stored or discharged into the environment. Method 800 returns.

[0063] Now go to Fig.10 , a flow chart of a method 1000 for automatically replenishing a neutralizing solution in a photocatalytic anesthetic waste gas treatment system is shown. In the photocatalytic anesthetic waste gas treatment system, a liquid replacement system (e.g., Figure 4 In some examples, when the anesthetic waste gas treatment system includes a hybrid PCO / neutralization reactor, a liquid replacement system may be included. In an alternative example, the liquid replacement system may be fluidly coupled to a separate neutralization reactor (e.g., Figure 3 334 of the neutralization reactor). Herein, method 1000 refers to a neutralization reactor, which may refer to a stand-alone neutralization reactor or a hybrid PCO / neutralization reactor. Method 1000 may occur in response to the controller determining that the pH of the neutralization solution is less than or equal to a threshold pH (e.g., yes at step 806 of method 800).

[0064] At 1002, method 1000 determines whether the self-sealing cartridge includes a fresh neutralization solution. The fresh neutralization solution includes an alkaline substance that reacts with the acidic byproduct to produce a neutral salt. The pH of the fresh neutralization solution can be greater than 7.5. If method 1000 determines that the self-sealing cartridge does not include a fresh neutralization solution (No), method 1000 continues to 1012 and includes reminding the user to replace the self-sealing fluid cartridge. Method 1000 returns.

[0065] If method 1000 determines that the self-sealing box does include fresh neutralization solution (yes), method 1000 proceeds to 1004 and includes opening a liquid shutoff valve. The liquid shutoff valve may be positioned in the fluid passage between the two-way pump of the liquid replacement system and the neutralization reactor. Opening the liquid shutoff valve may enable fluid to flow between the neutralization reactor and the liquid replacement system. At 1006, method 1000 includes starting a two-way pump in a first direction. Starting the two-way pump in a first direction may pump the neutralization solution used (e.g., pH≤7.5) from the neutralization reactor to the receiving chamber of the self-sealing fluid box. The controller may start the two-way pump in a first direction for a period of time, which duration is calibrated to empty the neutralization solution used in the neutralization reactor.

[0066] At 1008, method 1000 includes starting a bidirectional pump in a second direction. Starting the bidirectional pump in the second direction allows fresh neutralization solution to flow from the self-sealing fluid box to the neutralization reactor. The controller can start the bidirectional pump in the second direction for a period of time that is calibrated to fill the neutralization reactor with the fresh neutralization solution of the required amount. At 1010, method 1000 includes closing the liquid shutoff valve. Closing the liquid shutoff valve prevents further fluid flow between the neutralization reactor and the liquid replacement system. Method 1000 ends.

[0067] The technical effect of methods 700, 800, and 1000 is to degrade WAG gas into non-greenhouse gases and neutralize acid gas byproducts. The method can monitor and control PCO and neutralization reactions to prevent the introduction of harmful gases (e.g., acid gases or untreated WAG) into the enclosed space where the user is located. Treating WAG gas with PCO can prevent the introduction of greenhouse gases into the environment due to patient anesthesia. PCO can be made of readily available and abundant materials (e.g., TiO 2 and UV light) to degrade WAG gases into non-greenhouse gases.

[0068] The present disclosure also provides support for a method for treating anesthetic waste gas, the method comprising: flowing the anesthetic waste gas into the inlet of a photocatalytic oxidation reactor, operating one or more ultraviolet lamps of the photocatalytic oxidation reactor to trigger the oxide-catalyzed photodecomposition of the anesthetic waste gas and form acidic byproducts, and flowing the output of the photocatalytic oxidation reactor including the acidic byproducts into a neutralization reactor. In a first example of the method, the photocatalytic oxidation reactor is a packed bed photocatalytic oxidation reactor including wide bandgap semiconductor oxide-coated granules packed around one or more ultraviolet lamps. In a second example of the method that optionally includes the first example, the method further comprises: flowing the anesthetic waste gas through a flow sensor positioned upstream of the photocatalytic oxidation reactor, and in response to the output of the flow sensor indicating that the flow rate is higher than a threshold flow rate, directing the anesthetic waste gas to the input end of a gas accumulator positioned downstream of the flow sensor and upstream of the photocatalytic oxidation reactor. In a third example of the method that optionally includes one or both of the first and second examples, the neutralization reactor comprises an aqueous solution configured to neutralize the acidic byproducts and a pH sensor configured to measure the pH of the aqueous solution. In a fourth example of the method, which optionally includes one or more or each of the first to third examples, the method further includes: monitoring the pH of the aqueous solution, and generating an alarm in response to the monitored pH being less than or equal to 7.5. In a fifth example of the method, which optionally includes one or more or each of the first to fourth examples, the method further includes: monitoring the outlet of the neutralization reactor for penetrating anesthetic waste gas and / or acid gas, and in response to the presence of penetrating anesthetic waste gas and / or acid gas, diverting the anesthetic waste gas flow from the photocatalytic oxidation reactor to the removal system and generating an alarm. In a sixth example of the method, which optionally includes one or more or each of the first to fifth examples, the method further includes: measuring the concentration of acidic byproducts output from the photocatalytic oxidation reactor. In a seventh example of the method, which optionally includes one or more or each of the first to sixth examples, the method further includes: increasing the operating power of one or more ultraviolet lamps in response to the measured concentration of acidic byproducts being lower than a threshold concentration.

[0069] The present disclosure also provides support for an anesthetic waste gas treatment system, which includes: a gas accumulator configured to receive anesthetic waste gas and output anesthetic waste gas at or above a threshold pressure; and a packed bed photocatalytic oxidation reactor, which includes oxide-coated pellets filled around one or more ultraviolet lamps and is configured to receive the output of the gas accumulator. In a first example of the system, the gas accumulator includes a compressor and an accumulation tank fluidly coupled to the compressor, and the accumulation tank is directly positioned downstream of the packed bed photocatalytic oxidation reactor. In a second example of the system that optionally includes the first example, the packed bed photocatalytic oxidation reactor also includes an ultraviolet sensor. In a third example of the system that optionally includes one or both of the first and second examples, the system also includes: a neutralization reactor configured to receive decomposition gas byproducts from the output end of the packed bed photocatalytic oxidation reactor. In a fourth example of the system that optionally includes one or more or each of the first to third examples, the neutralization reactor includes an aqueous solution that is configured to neutralize acidic substances of the decomposition gas byproducts. In a fifth example of the system that optionally includes one or more or each of the first to fourth examples, the packed bed photocatalytic oxidation reactor also includes an aqueous solution in which oxide-coated pellets are suspended, the aqueous solution being configured to neutralize acidic byproducts produced by decomposition of anesthetic waste gases.

[0070] The present disclosure also provides support for an anesthetic waste gas treatment system, the anesthetic waste gas treatment system comprising: a photocatalytic oxidation reactor, the photocatalytic oxidation reactor comprising one or more ultraviolet lamps and configured to receive anesthetic waste gas and output decomposition gas byproducts; a neutralization reactor, the neutralization reactor fluidly coupled to the outlet of the photocatalytic oxidation reactor; a valve, the valve coupling the inlet of the anesthetic waste gas treatment system to the photocatalytic oxidation reactor, the accumulator and the outlet of the anesthetic waste gas treatment system; a chemical sensor, the chemical sensor is positioned at the outlet of the neutralization reactor; and a controller, the controller is communicatively coupled to the valve and the chemical, and includes instructions stored on a non-volatile memory, the instructions being executable to: monitor the output of the chemical sensor, actuate the valve in response to the output of the chemical sensor to direct the flow of anesthetic waste gas. In a first example of the system, the output of the chemical sensor indicates the concentration of the breakthrough gas. In a second example of the system that optionally includes the first example, the instructions also include actuating the valve in response to the output of the chemical sensor indicating that the concentration of the anesthetic waste gas is higher than the breakthrough concentration to direct the anesthetic waste gas away from the accumulator and the photocatalytic oxidation reactor and toward the outlet of the anesthetic waste gas treatment system. In a third example of the system optionally including one or both of the first and second examples, the photocatalytic oxidation reactor includes an ultraviolet transparent tube wrapped around at least one of the one or more ultraviolet lamps and an ultraviolet transmission optical fiber positioned in the lumen of the ultraviolet transparent tube, and the inner surface of the ultraviolet transparent tube is coated with an oxide catalyst. In a fourth example of the system optionally including one or more or each of the first to third examples, the neutralization reactor includes a cooling system and a temperature sensor configured to monitor the temperature of a coolant flowing through the cooling system. In a fifth example of the system optionally including one or more or each of the first to fourth examples, the instruction also includes increasing the power of the cooling system in response to the output of the temperature sensor indicating that the temperature of the coolant is above 50°C.

[0071] As used herein, the elements or steps listed in the singular and beginning with the word "one" or "an" should be understood as not excluding a plurality of the elements or steps, unless such exclusion is explicitly stated. In addition, the reference to "one embodiment" of the present invention is not intended to be interpreted as excluding the existence of additional embodiments that also include the cited features. In addition, unless explicitly stated to the contrary, "comprising", "including" or "having" an embodiment of an element or multiple elements with a specific characteristic may include additional such elements that do not have the characteristic. The terms "including" and "in..." are used as the concise language equivalents of the corresponding terms "including" and "wherein". In addition, the terms "first", "second" and "third" etc. are only used as marks, and are not intended to impose numerical requirements or specific positional order on their objects.

[0072] Figure 5 to Figure 6 An exemplary configuration for positioning each component relative to each other is shown. In at least one example, if it is shown as being in direct contact or directly coupled to each other, such elements may be referred to as being in direct contact or directly coupled, respectively. Similarly, in at least one example, elements that are shown as being adjacent or adjacent to each other may be adjacent or adjacent to each other, respectively. For example, components placed in coplanar contact with each other may be referred to as being in coplanar contact. For another example, in at least one example, elements that are positioned to be spaced apart from each other and have only space therebetween without other components may be described and referenced as such. For another example, elements that are shown to be located above / below each other, located on opposite sides of each other, or located on the left / right side of each other may be described and referenced as such relative to each other. In addition, as shown in the figure, in at least one example, the topmost element or the point of the element may be referred to as the "top" of the component, and the bottommost element or the point of the element may be referred to as the "bottom" of the component. As used herein, top / bottom, upper / lower, upper / lower may be relative to the vertical axis of the figure, and may be used to describe the position of the elements relative to each other in the figure. Thus, in one example, the element shown to be located above other elements is positioned vertically above other elements. For another example, the shapes of elements depicted in the figures may be referred to as having those shapes (e.g., such as being rounded, straight, planar, curved, rounded, chamfered, angled, etc.). Furthermore, in at least one example, elements shown as intersecting each other may be referred to as intersecting elements or intersecting each other. Additionally, in one example, elements shown as being within another element or shown as being outside another element may be described and referred to as such.

[0073] This written description uses examples to disclose the invention, including the best mode, and also to enable a person skilled in the relevant art to practice the invention, including making and using any devices or systems and performing any included methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to a person skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insignificant differences from the literal language of the claims.

Claims

1. A method for treating anesthetic waste gas, the method comprising: Allowing the anesthetic waste gas to flow into the inlet of the photocatalytic oxidation reactor (710); operating one or more ultraviolet lamps of the photocatalytic oxidation reactor to trigger oxidant-catalyzed photodecomposition of the anesthetic waste gas and form acidic byproducts; as well as The output of the photocatalytic oxidation reactor including the acidic byproducts is flowed (722) into a neutralization reactor.

2. The method of claim 1, wherein the photocatalytic oxidation reactor is a packed bed photocatalytic oxidation reactor comprising wide bandgap semiconductor oxide coated pellets packed around the one or more ultraviolet lamps.

3. The method according to claim 1 further includes allowing anesthetic waste gas to flow through a flow sensor positioned upstream of the photocatalytic oxidation reactor, and in response to the output of the flow sensor indicating a flow rate higher than a threshold flow rate, directing the anesthetic waste gas to an input end of a gas accumulator positioned downstream of the flow sensor and upstream of the photocatalytic oxidation reactor.

4. The method of claim 1, wherein the neutralization reactor comprises an aqueous solution configured to neutralize the acidic byproduct and a pH sensor configured to measure the pH of the aqueous solution, and the method further comprises monitoring the pH of the aqueous solution and generating an alarm in response to a monitored pH of less than or equal to 7.

5.

5. The method according to claim 1 further comprises monitoring the outlet of the neutralization reactor for penetrating anesthetic waste gas and / or acid gas, and in response to the presence of penetrating anesthetic waste gas and / or acid gas, diverting the anesthetic waste flow from the photocatalytic oxidation reactor to a removal system and generating an alarm.

6. The method of claim 1, further comprising measuring a concentration of the acidic byproducts output from the photocatalytic oxidation reactor, and further comprising increasing an operating power of the one or more ultraviolet lamps in response to the measured concentration of the acidic byproducts being below a threshold concentration.

7. An anesthetic waste gas treatment system, the anesthetic waste gas treatment system comprising: a gas accumulator (313) configured to receive waste anesthetic gas and output waste anesthetic gas at or above a threshold pressure; as well as A packed bed photocatalytic oxidation reactor (316) includes oxide-coated pellets (328) packed around one or more ultraviolet lamps (330b) and is configured to receive the output of the gas accumulator.

8. The anesthetic waste gas treatment system of claim 7, wherein the gas accumulator comprises a compressor and an accumulation tank fluidly coupled to the compressor, the accumulation tank being positioned directly downstream of the packed bed photocatalytic oxidation reactor.

9. The anesthetic waste gas treatment system according to claim 7, wherein the packed bed photocatalytic oxidation reactor further comprises an ultraviolet sensor.

10. An anesthetic waste gas treatment system according to claim 7, wherein the packed bed photocatalytic oxidation reactor also includes an aqueous solution in which the oxide-coated pellets are suspended, and the aqueous solution is configured to neutralize acidic byproducts generated by the decomposition of the anesthetic waste gas.

11. The anesthetic waste gas treatment system according to claim 7, further comprising a valve, wherein the valve couples the inlet of the anesthetic waste gas treatment system to the packed bed photocatalytic oxidation reactor, the gas accumulator, and the outlet of the anesthetic waste gas treatment system; a chemical sensor positioned at an outlet of the neutralization reactor; and a controller communicatively coupled to the valve and the chemical sensor and comprising instructions stored on a non-volatile memory, the instructions executable to: monitoring an output of the chemical sensor; The valve is actuated in response to the output of the chemical sensor to direct the flow of the waste anesthetic gas.

12. An anesthetic waste gas treatment system according to claim 11, wherein the output of the chemical sensor indicates the concentration of the breakthrough gas, and wherein the instructions also include actuating the valve to direct the anesthetic waste gas away from the gas accumulator and the packed bed photocatalytic oxidation reactor and toward the outlet of the anesthetic waste gas treatment system in response to the output of the chemical sensor indicating that the concentration of the anesthetic waste gas is higher than the breakthrough concentration.

13. An anesthetic waste gas treatment system according to claim 7, wherein the packed bed photocatalytic oxidation reactor comprises an ultraviolet transparent tube wound around at least one of the one or more ultraviolet lamps and an ultraviolet transmission optical fiber positioned in the lumen of the ultraviolet transparent tube, and the inner surface of the ultraviolet transparent tube is coated with an oxide catalyst.

14. An anesthetic waste gas treatment system according to claim 7, wherein the anesthetic waste gas treatment system also includes a neutralization reactor, wherein the neutralization reactor is configured to receive decomposition gas by-products from the output end of the packed bed photocatalytic oxidation reactor, and wherein the neutralization reactor includes an aqueous solution of an acidic substance configured to neutralize the decomposition gas by-products, and wherein the neutralization reactor includes a cooling system and a temperature sensor configured to monitor the temperature of a coolant flowing through the cooling system.

15. The anesthetic waste gas treatment system of claim 14, further comprising a controller communicatively coupled to the cooling system and comprising instructions stored on a non-volatile memory, the instructions executable to: The power of the cooling system is increased in response to the output of the temperature sensor indicating that the temperature of the coolant is above 50°C.

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