Process for separating gases and adsorbent compositions used therein
AssigneePraxair Technology, Inc.
InventorsJian Zheng, Neil Andrew Stephenson, Philip Alexander Barrett
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Abstract
The present invention relates generally to a composite adsorbent comprising at least a zeolite-containing CO2 removal adsorbent and 10% or more of a metal oxide having a heat capacity of at least 20 cal/mol-° K (83.7 J/(mol·K). The composite is preferably used in a multi-layered adsorption system in a cyclic adsorption process. The adsorption system comprises two or more layers wherein the first layer is at least a water vapor removal adsorbent, such as activated alumina, and the second layer is the novel composite adsorbent. The adsorption system is preferably used in a PSA prepurification process prior to cryogenic air separation.
Claims25
A multi-layered adsorption system for use in separating gases in a PSA or VPSA cyclic adsorption process comprising two or more adsorbent layers wherein the first layer is at least a water vapor removal adsorbent and the second layer is a composite adsorbent comprising agglomerated particles of 10-50% of a zeolite;
- 5-45% of activated alumina;
- and 10-50% of a metal oxide having a heat capacity of at least 20 cal/mol-° K (83.7 J/(mol·K)) in substantially uniform distribution and wherein the total of the zeolite, activated alumina and metal oxide equals 100 weight % as measured on a dry weight basis and the crush strength is more than about 4.5 Newtons (N) for particles in the 7×14 US mesh size range.
A composite adsorbent for use in removing at least CO2 from a process gas stream in a PSA or VPSA adsorption process comprising a zeolite-containing CO2 removal adsorbent comprising agglomerated particles of 10-50% of a zeolite;
- 5-45% of activated alumina;
- and 10-50% of a metal oxide having a heat capacity of at least 20 cal/mol-° K (83.7 J/(mol·K)) in substantially uniform distribution and wherein the total of the zeolite, activated alumina and metal oxide equals 100 weight % as measured on a dry weight basis and the crush strength is more than about 4.5 Newtons (N) for particles in the 7×14 US mesh size range.
A cyclic PSA or VPSA process for removing at least CO2 from a gas stream having less than 5% CO2, the process comprising contacting the gas stream with a multilayer adsorption system comprising two or more layers wherein the first layer is at least a water vapor removal adsorbent and the second layer is a composite comprising at least a zeolite-containing CO2 removal adsorbent and 10-50% of a zeolite;
- 5-45% of activated alumina;
- and 10-50% of metal oxide having a heat capacity of at least 20 cal/mol-° K (83.7 J/(mol·K)) and wherein the total of zeolite, activated alumina and metal oxide equals 100 weight % as measured on a dry weight basis and recovering the CO2 depleted gas stream.
Dependencies are inferred from the claim text.