Granular carbon dioxide (CO2) absorbent material for life support, diving, hyper- and hypobaric applications. Specification

2015 ◽  
1979 ◽  
Vol 6 (2) ◽  
pp. 105-109 ◽  
Author(s):  
Nicholas Polunin

An ecodisaster is here characterized as ‘any major and widespread misfortune to, or seriously detrimental change operating through, Man's or Nature's habitat—whether or not it is engendered by Man himself, and whether or not it affects him directly’.From this wide perspective but leaving aside such ‘old favourites’ as world famine and nuclear holocaust, and not yet dealing with population swarming and biotic invasion, are selected the following half-dozen items as being particularly pertinent: (1) Build-up of atmospheric carbon dioxide; (2) Disappearance of more and more of the life-support system; (3) Water shortage and salt build-up with continuing irrigation; (4) Loss of genetic diversity; (5) Increasing complexity of human existence and health-hazards; and (6) The Beirut syndrome of human slaughter.


2017 ◽  
Vol 19 (2) ◽  
pp. 114-121 ◽  
Author(s):  
Carole Cummins ◽  
Andrew Bentley ◽  
Daniel F McAuley ◽  
James J McNamee ◽  
Hannah Patrick ◽  
...  

Introduction Extracorporeal membrane carbon dioxide removal may have a role in treatment of patients with hypercapnic respiratory failure and refractory hypoxaemia and/or hypercapnia. Methods We report on the use, outcomes and complications in United Kingdom intensive care units reporting patients on the Extracorporal Life Support Organisation register. Results Of 60 patients, 42 (70%) had primarily hypoxic respiratory failure and 18 (30%) primarily hypercapnic respiratory failure. Use of veno-venous procedures increased compared to arterio-venous procedures. Following extracorporeal membrane carbon dioxide removal, ventilatory and blood gas parameters improved at 24 h. Twenty-seven (45%) of patients died before ICU discharge, while 27 (45%) of patients were discharged alive. The most common complications related to thrombosis or haemorrhage. Discussion There is limited use of extracorporeal membrane carbon dioxide removal in UK clinical practice and outcomes reflect variability in indications and the technology used. Usage is likely to increase with the availability of new, simpler, technology. Further high quality evidence is needed.


Author(s):  
M. Nuckols ◽  
S. Kolaczkowski ◽  
S. Awdry ◽  
T. Smith ◽  
D. Thomas

Traditional CO2 absorption methods for underwater life support equipment use alkali metal hydroxide chemical beds — mostly calcium hydroxide — that have been shown to have poor absorption efficiencies at cold temperatures, and must be replaced at considerable trouble and expense on a frequent basis. With chemical utilizations as low as 20% in water temperatures of 2°C, these hydroxides do not lend themselves to applications requiring extended durations in cold water due to the inability to carry sufficient quantities of expendables. A joint research effort between Duke University and the University of Bath has verified the feasibility in laboratory trials of an alternative carbon dioxide removal method that intimately mixes seawater with breathing circuit gases within a packed bed of Dixon rings. Based on the results of these laboratory trials, two multi-path scrubber prototypes were designed and fabricated for unmanned testing. In March 2013, the hyperbaric performance of these prototype scrubbers was characterized over a wide range of gas and water flow rates when operating the scrubbers in counter-current (water flowing in the opposite direction as gas flow) and co-current (water flowing in the same direction as gas flow) fashion. Significant findings from these tests included the following: • Both scrubber prototypes were found to be capable of delivering exit CO2 levels below 0.5 vol% (surface equivalent) at respiratory rates up to 22.5 liters per minute and at depths ranging from 0 to 40 meters of seawater (MSW). • Negligible collateral O2 absorption was observed at surface pressure (exit O2 levels were typically above 20.2 vol%), and exit O2 levels were typically above 18.4% during testing at 10 MSW. • At surface pressure, both prototypes had significantly lower breathing resistances than design goals established by the U. S. Navy.


1978 ◽  
Vol 100 (3) ◽  
pp. 383-385 ◽  
Author(s):  
M. Onischak ◽  
B. Baker

The design and development of a prototype carbon dioxide absorber using potassium carbonate (K2CO3) is described. Absorbers are constructed of thin, porous sheets of supported K2CO3 that are spirally wound to form a cylindrical reactor. Axial gas passages are formed between the porous sheets by corrugated screen material. Carbon dioxide and water in an enclosed life support system atmosphere react with potassium carbonate to form potassium bicarbonate. The potassium carbonate is regenerated by heating the potassium bicarbonate to 150° C at ambient pressure. The extravehicular mission design conditions are for one man for 8 h. Results are shown for a subunit test module investigating the effects of heat release, length-to-diameter ratio, and active cooling upon performance. The most important effect upon carbon dioxide removal is the temperature of the potassium carbonate.


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