# US 12,599,869 B2 · Gas separation method and gas separation apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,599,869 B2 - Document ID: US12599869B2 - Status: Granted - Kind: B2 - Application number: 18/308,352 - Filed: 2023-04-27 - Published: 2023-08-24 - Granted: 2026-04-14 - Earliest claimed: 2020-10-29 - Assignees: Mitsubishi Chemical Corporation - Applicants: Mitsubishi Chemical Corporation - Inventors: Naoki Noguchi - Web page: https://patentgrep.com/patent/US12599869B2 ## CPC - B01D 53/22: by diffusion (manufacturing semi-permeable membranes B01D67/00; form, structure or properties of semi-permeable membranes B01D69/00; material for semi-permeable membranes B01D71/00) - B01D 53/30: Controlling by gas-analysis apparatus (regulating non electrical variables in general G05D) - C07C 7/144: using membranes, e.g. selective permeation - B01D 2256/245: Methane - B01D 2257/504: Carbon dioxide - B01D 2257/7025: Methane - B01D 2258/05: Biogas - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) - C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS ## Abstract A gas separation method including performing a gas separation operation that separates a source gas into a primary-side gas and a secondary-side gas with a membrane of a membrane module. The source gas contains a combustible component. The gas separation operation includes pressurizing the source gas and supplying the source gas to a primary side of the membrane module and depressurizing a secondary side of the membrane module to a pressure lower than an atmospheric pressure. The primary-side gas has a higher concentration of the combustible component than the secondary-side gas, and the gas separation method further includes detecting a composition of the secondary-side gas and stopping the gas separation operation in an instance in which the composition enters a specified range. ## Claims ### Claim 1 A gas separation apparatus comprising a membrane separation device that comprises: a membrane module that separates a source gas into a primary-side gas and a secondary-side gas with a membrane of the membrane module, wherein the source gas contains a combustible component, wherein the primary-side gas has a higher concentration of the combustible component than the secondary-side gas; a supply line including a pressure pump that pressurizes the source gas and supplies the source gas to a primary side of the membrane module; and a permeate line including a vacuum pump that depressurizes a secondary side of the membrane module, wherein the membrane separation device includes: a detector that detects a composition of the secondary-side gas, and a controller that stops the pressure pump and the vacuum pump in an instance in which the composition reaches a specified range, wherein the membrane of the membrane module has a separation factor greater than or equal to 80. ### Claim 2 A gas separation apparatus comprising a membrane separation device that comprises: a membrane module that separates a source gas into a primary-side gas and a secondary-side gas with a membrane of the membrane module, wherein the source gas contains a combustible component, wherein the primary-side gas has a higher concentration of the combustible component than the secondary-side gas; a supply line including a pressure pump that pressurizes the source gas and supplies the source gas to a primary side of the membrane module; and a permeate line including a vacuum pump that depressurizes a secondary side of the membrane module, wherein the membrane separation device includes: a detector that detects a pressure or a flow rate of the secondary side, and a controller that stops the pressure pump and the vacuum pump in an instance in which the pressure or the flow rate of the secondary side becomes greater than a reference value, wherein the membrane of the membrane module has a separation factor greater than or equal to 80. ### Claim 3 (depends on 2) The gas separation apparatus according to claim 2, wherein the reference value is a value at least 10 kPaG higher than a default value in an instance of the pressure, and wherein the reference value is a value at least 50% higher than a default value in an instance of the flow rate. ### Claim 4 (depends on 1) The gas separation apparatus according to claim 1, further comprising a valve controller, wherein the valve controller causes valves to be closed in the instance in which the composition reaches the specified range, where one of the valves is disposed in a supply line for supplying the source gas to the membrane module, and another of the valves is disposed in a depressurization line of the membrane module. ### Claim 5 (depends on 1) The gas separation apparatus according to claim 1, wherein the specified range is an explosive range. ### Claim 6 (depends on 1) The gas separation apparatus according to claim 1, wherein the combustible component is methane, and the source gas further comprises carbon dioxide. ### Claim 7 (depends on 1) The gas separation apparatus according to claim 1, wherein the vacuum pump is a vacuum pump that reduces a pressure of the secondary side to less than or equal to −30 kPaG. ### Claim 8 (depends on 1) The gas separation apparatus according to claim 1, wherein, in an instance in which the source gas is inadvertently introduced, the composition enters the specified range. ### Claim 9 (depends on 1) The gas separation apparatus according to claim 1, wherein the source gas is a biogas. ### Claim 10 (depends on 2) The gas separation apparatus according to claim 2, wherein the combustible component is methane, and the source gas further comprises carbon dioxide. ### Claim 11 (depends on 1) A gas separation method, comprising: performing a gas separation operation with the gas separation apparatus of claim 1 that separates the source gas into the primary-side gas and the secondary-side gas with the membrane of the membrane module, wherein the source gas contains a combustible component, the gas separation operation including: pressurizing the source gas and supplying the source gas to the primary side of the membrane module, and depressurizing the secondary side of the membrane module to a pressure lower than an atmospheric pressure; wherein the primary-side gas has a higher concentration of the combustible component than the secondary-side gas, and wherein the gas separation method further includes detecting the composition of the secondary-side gas; and stopping the gas separation operation in an instance in which the composition enters the specified range. ### Claim 12 (depends on 2) A gas separation method, comprising: performing a gas separation operation with the gas separation apparatus of claim 2 that separates the source gas into the primary-side gas and the secondary-side gas with the membrane of the membrane module, wherein the source gas contains a combustible component, the gas separation operation including: pressurizing the source gas and supplying the source gas to the primary side of the membrane module, and depressurizing the secondary side of the membrane module to a pressure lower than an atmospheric pressure; wherein the primary-side gas has a higher concentration of the combustible component than the secondary-side gas, and wherein the gas separation method further includes detecting the pressure or the flow rate of the secondary side; and stopping the gas separation operation in an instance in which a detected pressure or the pressure or the flow rate exceeds the reference value. ### Claim 13 (depends on 12) The gas separation method according to claim 12, wherein the reference value is a value at least 10 kPaG higher than a default value in an instance of the detected pressure, and wherein the reference value is a value at least 50% higher than a default value in an instance of the flow rate. ### Claim 14 (depends on 11) The gas separation method according to claim 11, wherein, in the instance in which the composition enters the specified range, valves are closed, where one of the valves is disposed in the supply line for supplying the source gas to the membrane module, and another of the valves is disposed in a depressurization line of the membrane module. ### Claim 15 (depends on 11) The gas separation method according to claim 11, wherein the specified range is an explosive range. ### Claim 16 (depends on 11) The gas separation method according to claim 11, wherein the combustible component is methane. ### Claim 17 (depends on 11) The gas separation method according to claim 11, wherein the pressure of the secondary side is reduced to a pressure 30 kPa or more lower than the atmospheric pressure. ### Claim 18 (depends on 11) The gas separation method according to claim 11, wherein, in an instance in which the source gas is inadvertently introduced, the composition enters the specified range. ### Claim 19 (depends on 11) The gas separation method according to claim 11, wherein the source gas is a biogas.