Environmental Control in Manned Spacecraft Atmosphere

(1) Carbondioxide Adsorption by Solid Amine

Abstract

A well-controlled gas exchanging system provides a reliable and comfortable condition to crews in a perfectly closed atmosphere such as spacecraft. Carbon dioxide (CO₂) generated with human metabolism must be controlled within a low level concentration because of physiological reasons. Some chemical substances are well known to remove rare CO₂ gas in a cabin atmosphere. Lithium hydroxide and zeolite molecular sieves have been utilized to prevent an atmosphere CO₂ concentration from increasing in spacecraft, submarine, and so forth. A new CO₂ removal agent called Solid Amine repeatedly works well in adsorbing CO₂ gas component independent of moisture in a cabin atmosphere. In general, solid amine is composed of porous material with amine groups on it and has a large amount of surface area. This type of adsorbent, however, has not yet utilized in closed gas control system. This paper deals with some basic characteristics of solid amine concerning adsorption capability (adsorption isotherm), characteristics of dynamic adsorptions (breakthrough phenomena in a fixed bed), and diffusion mechanism of CO₂ molecule into adsorbent surface pores.