Patent ID: 11872520
Assignee: NGK INSULATORS, LTD.
Field: Chemical engineering (Chemistry)
Classification: CPC B  Y | IPC B

Claim 0:
1. A method for inspecting a separation membrane module, the separation module comprising a separation membrane structure that has a porous body and a zeolite membrane assembled and sealed in a casing to form a primary side of the zeolite membrane and a secondary side of the zeolite membrane, and the method comprising:
sealing a gas for inspection on the primary side of the zeolite membrane;
evaluating a total leak amount for the gas for inspection to the secondary side of the zeolite membrane, after the sealing step;
calculating a membrane defect leak amount caused by a membrane defect in the zeolite membrane based on a membrane defect leak amount equation below;
calculating a seal leak amount caused by seal failure in the separation membrane structure by subtracting the membrane defect leak amount from the total leak amount; and
evaluating whether a gas leak in the separation membrane module due to a seal leak is acceptable based on a predetermined threshold of the seal leak amount;
wherein a dynamic molecular diameter of the gas for inspection is greater than 1.07 times a pore diameter of the zeolite membrane;
the gas for inspection exhibits a characteristic of having a reduction rate of a CO2 gas permeation rate for the zeolite membrane of less than 10%; the reduction rate of the CO2 gas permeation rate is determined by
supplying CO2 gas at 0.1 MPaG to the primary side of the zeolite membrane,
measuring a CO2 gas permeation rate based on a permeation flow amount of CO2 gas that has permeated to the secondary side of the zeolite membrane,
exposing the zeolite membrane to the gas for inspection at 25 degrees C. and 0.1 MPaG for 60 minutes,
resupplying CO2 gas at 0.1 MPaG to the primary side of the zeolite membrane again,
remeasuring a CO2 gas permeation rate based on a permeation flow amount of CO2 gas that has permeated to the secondary side of the zeolite membrane, and
calculating the reduction rate for the CO2 gas permeation rate by subtracting the CO2 gas permeation rate that was measured after exposure to the gas for inspection from the CO2 gas permeation rate that was measured prior to exposure to the gas for inspection and then dividing the value by the CO2 gas permeation rate prior to exposure;
membrane defect leak amount equation: Tb=A×(PH+PL)+B, where Tb denotes the membrane defect leak amount caused by the membrane defect in the zeolite membrane, PH denotes a pressure on the primary side, PL denotes a pressure on the secondary side, A denotes a slope of the line of a straight line resulting from the membrane defect leak amount equation, and B denotes a y-intercept resulting from the membrane defect leak amount equation; and
a pressure of the gas for inspection on the primary side when acquiring the membrane defect leak amount equation is less than a pressure of the gas for inspection when evaluating the total leak amount.