Within the closed system of a manned space station or other such environments, it is necessary to establish a life support system which removes CO2 produced by metabolism and produces O2. As a step in that direction, we have performed numerical simulations of CO2 adsorption and desorption based on the basic data such as adsorption equilibria and overall mass transfer coefficients. These data were previously determined with respect to a system of CO2 removal and concentration using solid amine. We then selected the optimum operating conditions by examining the influence of each parameter on CO2 recovery performance. The results indicate that the optimum operating conditions for recovery of CO2 produced by two persons are an adsorption column size of 0.24 m inner diameter and 0.20 m height and a desorption steam rate of 0.4kg·h-1, under a desorption pressure of 0.1 MPa. In addition, it has become clear that when the closed system of a manned space station is operated under such conditions, the specified performance can be sufficiently maintained even if adsorption gas temperature and humidity vary within the supposed conditions. © 1990, The Society of Chemical Engineers, Japan. All rights reserved.