Process and apparatus to recover high purity carbon dioxide

摘要

The present invention generally relates to vacuum pressure swing adsorption (VPSA) processes and apparatus to recover carbon dioxide having a purity of approximately >=90 mole % from streams containing at least carbon dioxide and hydrogen (e.g., syngas). The feed to the CO₂ VPSA unit can be at super ambient pressure. The CO₂ VPSA unit produces three streams, a H₂-enriched stream, a H₂-depleted stream and a CO₂ product stream. When the CO₂ VPSA unit is installed between an SMR/shift reactor and a H₂ PSA unit, hydrogen recovery is expected to be increased by extracting CO₂, thereby increasing hydrogen partial pressure in the H₂ PSA feed. The recovered CO₂ can be further upgraded, sequestered or used in applications such as enhanced oil recovery (EOR).