Abstract:

In the process of removing H₂S from natural gas usng a single MDEA solution, both H₂S and total sulfur content in the output gas always cannot meet the quality requirements of national class II natural gas with the continuous increase of organic sulfur content. After changing the key parameters, the desulfurization effect still could not be improved. Therefore, for the high content of organic sulfur, this paper carried out the research on the compound of MDEA+DIPA, MDEA+DEA, sulfolane+MDEA and sulfolane+DIPA four groups of efficient desulfurizers. By comparing the absorption partial pressure of H₂S and organic sulfur in solution, the better absorption desulfurizer combination was selected as sulfolane+MDEA. Then, the BBD response surface methodology was used according to the different ratio of sulfoxane, MDEA and H₂O as variables, and the optimal ratio of H₂S and total sulfur removal rate was optimized as the objective function. After mixing experiments and composite optimization, the optimal ratio of desulfurizer was obtained as 23.3% sulfoxane+54.6% MDEA+22.1% H₂O. The results of the optimal proportion of desulfurizer after the use of the field device showed that the removal rate of H₂S reached 99.964%, the removal rate of total sulfur was 99.833%, the content of H₂S in the effluent gas was 14.4mg/m³ and the total sulfur content was 78.5mg/m³, which met the national standard of class II gas.

Key words: natural gas, hydrogen sulfide, organic sulfur, desulfurizer, response surface methodology, composition adjustment

摘要：

在使用单一甲基二乙醇胺（MDEA）溶液脱除天然气中H₂S的过程中，随着有机硫含量不断地增加，常常造成出料气中H₂S和总硫含量均不能满足国家二类天然气质量要求。在改变关键参数后，脱硫效果仍然不能改善。因此，本文针对高含量的有机硫，开展了MDEA+DIPA、MDEA+DEA、环丁砜+MDEA、环丁砜+DIPA 4组高效脱硫剂的复配研究，通过对比H₂S及有机硫在溶液中的吸收分压，筛选出了吸收效果较优的脱硫剂组合为：环丁砜+MDEA。随后再利用BBD响应面分析法，以环丁砜、MDEA、H₂O的不同配比为变量，以H₂S和总硫脱除率最高为目标函数进行寻优，经过混料实验与复合优化，最终得出最优脱硫剂配比为：23.3%环丁砜+54.6%MDEA+22.1%H₂O。最优配比脱硫剂经现场装置使用后的效果表明，H₂S脱除率达到99.964%，总硫脱除率达到99.833%，出料气中H₂S含量为14.4mg/m³，总硫含量为78.5mg/m³，满足二类气标准。

关键词: 天然气, 硫化氢, 有机硫, 脱硫剂, 响应面分析法, 配比优化