Abstract: Coal-based H₂ generation has abruptly increased in recent years. The PSA-VPSA-SC process is the matured and standard framework for H₂ purification and CO₂ capture in many existing plants, including normal and vacuum pressure swing adsorption units in series (PSA-VPSA), and shallow condensation unit (SC). However, this standard process is frequently subjected to low H₂ recovery ratio and high purification cost. In this work, H₂-selective and CO₂-selective membrane units, i.e., HM and CO₂M, are attempted to support the standard process and ameliorate constraints. In the beginning, HM unit is arranged after VPSA to enhance H₂ recovery from the decarbonized stream, i.e., the PSA-VPSA-SC/HM process. As a result, H₂ recovery ratio can be enhanced significantly from 83% to 98%. In the following, VPSA is replaced with CO₂M unit to reduce investment and operation cost, i.e., the PSA-CO₂M-SC/HM process. Accordingly, the specific purification cost is diminished from 33.46 to 32.02 USD·(10³m³ H₂)^-1, saved by 4.3%, meanwhile the construction cost is falling back and just a little higher than that for the standard process. In the end, another CO₂M unit is launched before PSA, i.e., the CO₂M-PSA-CO₂M-SC/HM process, which could unbundle CO₂ enrichment partially from H₂ purification, and then save more investment and operation cost. In comparison with the standard process, this ultimate retrofitted process can be superior in all the three crucial indices, i.e., recovery ratio, investment, and specific purification cost. On the whole, coal-based H₂ generation can be ameliorated significantly through high efficient H₂-selective and CO₂-selective membrane units.

Key words: Hydrogen production, Separation, Membranes, Process framework, H₂-selectivemembrane, CO₂-selectivemembrane

摘要： Coal-based H₂ generation has abruptly increased in recent years. The PSA-VPSA-SC process is the matured and standard framework for H₂ purification and CO₂ capture in many existing plants, including normal and vacuum pressure swing adsorption units in series (PSA-VPSA), and shallow condensation unit (SC). However, this standard process is frequently subjected to low H₂ recovery ratio and high purification cost. In this work, H₂-selective and CO₂-selective membrane units, i.e., HM and CO₂M, are attempted to support the standard process and ameliorate constraints. In the beginning, HM unit is arranged after VPSA to enhance H₂ recovery from the decarbonized stream, i.e., the PSA-VPSA-SC/HM process. As a result, H₂ recovery ratio can be enhanced significantly from 83% to 98%. In the following, VPSA is replaced with CO₂M unit to reduce investment and operation cost, i.e., the PSA-CO₂M-SC/HM process. Accordingly, the specific purification cost is diminished from 33.46 to 32.02 USD·(10³m³ H₂)^-1, saved by 4.3%, meanwhile the construction cost is falling back and just a little higher than that for the standard process. In the end, another CO₂M unit is launched before PSA, i.e., the CO₂M-PSA-CO₂M-SC/HM process, which could unbundle CO₂ enrichment partially from H₂ purification, and then save more investment and operation cost. In comparison with the standard process, this ultimate retrofitted process can be superior in all the three crucial indices, i.e., recovery ratio, investment, and specific purification cost. On the whole, coal-based H₂ generation can be ameliorated significantly through high efficient H₂-selective and CO₂-selective membrane units.

关键词: Hydrogen production, Separation, Membranes, Process framework, H₂-selectivemembrane, CO₂-selectivemembrane