H2O对空间站5A分子筛CO2去除性能影响

为进一步研究分子筛CO2去除系统应用于空间站的工作可靠性和鲁棒性,针对空间站4床分子筛(4-BMS)系统中可能出现的湿度失效保护问题展开了实验研究.测试了两种载人航天分子筛材料TC-5A与PSA-5A,研究了不同相对湿度对CO2吸附性能的影响;比较了相同湿度条件下,进口气体CO2浓度、粒径及吸附温度的变化对分子筛吸附CO2性能的影响,采用不同实验方法探究了H2O和CO2在两种分子筛材料中的竞争吸附关系.结果表明:PSA-5A吸附CO2性能优于TC-5A,但对H2O的吸附率略低于TC-5A.H2O的存在对分子筛吸附CO2影响非常大,空气中相对湿度达到60%时,分子筛基本失去了吸附CO2的能力.此外,温度升高会造成CO2的吸附量显著下降,但对H2O的吸附量影响相对较小,尤其是当相对湿度较高时.这对中国未来长期运行的空间站分子筛CO2去除系统工作有效性与工作鲁棒性的评价具有指导意义.

H2O impact on CO2 removal performance of 5A molecular sieve in space station

For the further research on reliability and robustness of molecular sieve CO₂ removal system applied to the space station, the problem of the humidity failure protection of 4-bed molecular sieves (4-BMS) system in the space station was proposed and studied. The experiment was set up to test the impact of the CO₂ absorbing capacity under different relative humidity of gas in two kinds of molecular sieves (TC-5A and PSA-5A) for crewed space mission. Meanwhile, it compared the effect of CO₂ adsorption when CO₂ concentration of inlet gas, particles and temperature changed under the definite humidity, and explored the competitive adsorption between CO₂ and H₂O in TC-5A and PSA-5A using different measures. Results show that the PSA-5A has a better performance on CO₂ adsorption, but slightly less than TC-5A on H₂O adsorption capacity. And presence of H₂O in the air had a great influence on molecular sieve adsorption of CO₂, when the relative humidity reached the 60%, the molecular sieve has basically lose the CO₂ adsorption capacity. Besides, the TC-5A and the PSA-5A CO₂ adsorption capacity drop significantly when the temperature rises, but has a relatively less impact on H₂O adsorption, especially when RH is high. The experimental study can play a guiding role in evaluation of system reliability and robustness for the long-term orbiting space station study.