Endothermal carbon dioxide absorption

• US 4,039,620 A
• Filed: 04/25/1975
• Issued: 08/02/1977
• Est. Priority Date: 04/29/1974
• Status: Expired due to Term

• Current Assignee: Figgie International, Inc. (Johnson Controls International plc)
• Original Assignee: A-T-O Incorporated
• Inventors: Netteland, Loyal G., Heintz, Clifford E.
• Primary Examiner(s): Michell, Robert W.
• Assistant Examiner(s): Recla, Henry J.
• Application Number:
  US05/571,721
• Time in Patent Office: 830 Days
• Field of Search: 128/191 R, 128/142, 128/142.2, 128/142.3, 128/142.4, 128/204, 128/188, 128/142.6, 128/202, 128/203, 423/230, 423/624, 423/422, 98/1.5
• US Class Current: 423/230
• CPC Class Codes: A62B 19/00 Cartridges with absorbing substances for respiratory apparatus carbon dioxide absorbing devices A61M16/22
• CPC Class Codes: A62D 9/00 Composition of chemical substances for use in breathing apparatus

Abstract

The absorption of CO₂ from gas streams by lithium hydroxide can be caused to proceed at least partially by the reaction ##STR1## The reaction is endothermal, and more efficient than the normally occurring reaction. The presence of a molecular sieve and water favor the bicarbonate reaction.

Claims

1. The method of removing carbon dioxide from a gas stream containing moisture, at least in part according to the reaction ##STR3## comprising the steps of passing the gas stream directly through lithuim hydroxide and immediately thereafter through a molecular sieve.

2. The method of claim 1 comprising the steps of first passing the gas stream through a first chamber containing lithium hydroxide as the carbon dioxide absorbent;

immediately thereafter passing the stream through a second chamber containing hydrated molecular seive containing about 40 to 60 moles of water, per mole of said seive; and

removing from said second chamber a gas stream having reduced levels of CO₂ and moisture.

3. The method of claim 2 wherein the molecular seive is a crystalline zeolite.

4. The method of claim 3 wherein the zeolite is zeolite X.

5. The method of claim 4 wherein the zeolite is zeolite 13X.

6. The method of claim 2 wherein at least some of the removed gas stream is recirculated through the first chamber containing lithium hydroxide and then through the second chamber containing the molecular seive until the carbon dioxide is substantially removed and the relative humidity is reduced to a very low level.

7. The method of claim 6 wherein the molecular seive is crystalline zeolite.

8. The method of claim 7 wherein the zeolite is zeolite X.

9. The method of claim 7 wherein the zeolite is zeolite 13X.