| 摘要: |
| 原料天然气中二氧化碳(CO2)、羰基硫(COS)、硫化氢(H2S)和甲硫醇(CH3SH)等酸性气体需要通过碱性溶剂处理予以脱除，在吸收过程中以瞬时质子机理反应的H2S脱除速率远远快于COS和CO2，因此尽管在原料气中COS含量通常远低于H2S，但用于脱除H2S的常规技术不能完全有效地脱除COS。由于COS在结构上与CO2相似，但吸收速率通常远不及CO2吸收快，因此在保留部分CO2且深度脱除COS存在较大的技术与成本挑战。本文对有机胺法吸收CO2及COS的机理研究进展进行了总结：（1）在机理研究方面，普遍认为COS在一级醇胺和二级醇胺中的吸收机理与CO2吸收机理相同;（2）醇胺吸收CO2的机理通常认为是通过形成氨基甲酸盐而脱除CO2，进一步的加热分解即是CO2的释放与吸收液的循环使用;（3）COS与CO2均属线性分子，二者结构非常相似，物理化学性质也非常接近，这为客观上解决COS/CO2间的COS选择性吸收带来了巨大挑战。目前，对COS和CO2吸收机理差异性的机理研究非常缺乏，这样就导致了在大量CO2存在下的选择性COS吸收剂的设计缺乏理论依据，因此，深入研究COS的吸收机制存在明显的迫切性。 |
| 关键词: 羰基硫 二氧化碳 天然气净化 吸收机理 |
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| 基金项目:中国石油西南油气田分公司科技项目“羰基硫选择性脱除溶剂的开发研究（20230306-02） |
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| Research progress on the removal mechanism of carbon dioxide and carbonyl sulfur in natural gas |
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薛靖文1,2, zhuwenzhao1,2, gaofeng1,2, ranlongchao3,4, He Yun3,4, Zhang Wei3,4, Li Shuanglong5, yinguochuan5
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1.Research Institute of Natural Gas Technology, PetroChina Southwest Oil &2.Gas Field Company;3.Natural Gas Purification Plant General, PetroChina Southwest Oil &4.Gasfield Company;5.Huazhong University of Science and Technology
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| Abstract: |
| Carbon dioxide (CO2), carbonyl suifide (COS), hydrogen sulfide (H2S), methyl mercaptan, etc. in natural gases usually are required pretreatment to remove. The removal rate of H2S in alkaline solvent is much faster than that of COS and CO2. Therefore, although COS is usually less abundant than H2S in the feed gas, conventional techniques to remove H2S are not fully effective in removing COS. Despite the similar structure between COS and CO2, the absorption rate of COS is usually much slower than CO2 absorption, therefore, complete removal of COS presents significant technical and cost challenges. This article summarizes the research progress on the mechanism of CO2 and COS absorption in organic amine solutions: (1) In terms of mechanism studies, it’s generally believed that the absorption mechanism of COS in primary and secondary alkanol amines is the same as that of CO2; (2) The mechanism of CO2 absorption by alcohol amines is generally considered to be the absorption of CO2 through the formation of carbaminate, and further heating decomposition leads to the release of CO2 and the recycling of the absorption solution; (3) Both COS and CO2 are linear molecules with very similar structures and physicochemical properties, which brings great challenges on the selective COS absorption between COS/CO2. At Present, there is a lack of research on the differences between COS and CO2 absorption mechanisms, which leads to the lack of theoretical basis for the design of specific COS absorbers in the presence of a large amount of CO2. Therefore, it is an obvious urgency to further study the absorption mechanism of COS. |
| Key words: carbonyl suifide carbon dioxide natural gas purification absorption mechanism |
