A Steady-state Simulation Model of Gas Separation System by Hollow-filament Type Membrane Module.

Abstract

A steady-state simulation model of the gas separation system using a hollow-filament type membrane has been proposed. The mass transfer coefficients in the non-porous thin layer, in the porous support layer of the membrane and in the boundary layer of the membrane surface are estimated in the model. The four types of flow patterns: cross flow, mixing flow, concurrent flow and counter current flow, are also considered in the model. The mass transfer through the non-porous thin layer of the membrane controls the overall mass transfer by ~99%. The experimental observations of TPL (Tritium Process Laboratory in JAERI) for N2–H2 and Air—H2 systems agreed with the calculated results of the cross flow under a set of typical conditions (disposal volume of 2.78×10−3 Nm3/s, feed-side pressure of 3.44×105Pa, and permeated-side pressure of 1.07×104 Pa). The validity of the simulation method was thus proved. For Air-H2-H2O system also, the recovery ratios calculated for H2 are in good agreement with the experimental observations. However, the calculated recovery ratios of water vapor were slightly smaller than the experimental observations. This discrepancy may result from the difference in separation mechanism between H2 and water vapor, or the construction change of membrane caused by the existence of water vapor.