Regenerable adsorption beds for long-term life support systems include synthetic geolite to remove carbon dioxide and silica gel to dehumidify the atmospheric gas prior to its passage through the geolite beds. Bed performance is evaluated from adsorption characteristics, heat and mass transfer, and pressure drop

Blakely, R. L.

Jackson, J. K.

English

NASA Technical Reports Server

June 1970
	 Brief 70-10294 
NASA TECH BRIEF 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage commercial 
application. Tech Briefs are available on a subscription basis from the Clearinghouse for Federal Scientific and Technical 
Information, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Division, NASA, Code UT, Washington, D.C. 20546. 
Design Method for Adsorption Beds 
The problem: 
Carbon dioxide is constantly generated by the 
human breathing cycle so that a carbon dioxide re-
moval cycle is required whenever humans are confined 
over long periods in any space lacking an air-changing 
capability. There have been several submarine acci-
dents in which crews were lost due to this phenomenon 
although ample oxygen was available in the enclosure. 
For time increments of up to 14 days, the problem has 
been overcome by a system of carbon dioxide removal 
through adsorption on expendable lithium hydroxide 
beds. Such a system is, however, useful for longer 
periods only where bulk and weight are not considera-
tions; otherwise a regenerable system is required. 
The solution: 
A study has been made to define the parameters 
required to design regenerable adsorption beds for 
long-term life support systems. A typical system 
inludes synthetic geolite to remove the carbon dioxide 
and silica gel to dehumidify the atmospheric gas prior 
to its passage through the geolite beds. 
Bed performance is evaluated from correlated test 
data which include adsorption characteristics, heat 
and mass transfer, and pressure drop. A linearized 
solution of the dynamic mass transfer equations is 
included to provide a simplified method of bed design. 
This method is used to find the optimum design for a
typical four-bed regenerable, isothermal carbon diox-
ide removal system. The results of this simplified 
analysis are compared with those of a detailed digital 
computer study which reveals that the simplified 
method predicts system weight approximately 10 per-
cent higher than the detailed evaluation, an accept-
able accuracy for preliminary design calculations. 
Note: 
The following documentation may be obtained 
from:
Clearinghouse for Federal Scientific 
and Technical Information 
Springfield, Virginia 22151 
Single document price $3.00 
(or microfiche $0.65) 
Reference: 
NASA-CR-891 (N67-37320), Engineer-
ing Criteria for Spacecraft Cabin Atmos-
phere Selection 
Patent status: 
No patent action is contemplated by NASA. 
Source: J. Jackson and R. Blakely of 
McDonnell Douglas Corporation 
under contract to 
NASA Headquarters 
(HQN- 10269) 
Category 04 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
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Design method for adsorption beds

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