Gas separation method and gas separation apparatus

A gas separation method, comprising:

• 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,
• wherein the source gas contains a combustible component,
• the gas separation operation including:
• 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,
• 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 a pressure or a flow rate of the secondary side and stopping the gas separation operation in an instance in which a detected pressure or flow rate exceeds a reference value.

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.

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.