MDEA/DEA脱硫脱碳混合溶液在长庆气区的应用

随着长庆气区靖边等气田的不断开发，其天然气气质发生了较大变化，其中H2S含量上升到1 000 mg/m3，CO2体积分数上升到4.5%～6.0%，原天然气净化工艺采用的单一MDEA溶液已不能满足天然气脱硫脱碳需要。为此，开展了不同体积比MDEA/DEA混合醇胺溶液脱硫脱碳试验。试验结果显示：在相同的试验条件下，溶液中总胺为40%（质量分数），DEA与MDEA体积比为1∶6配比制成的混合溶液其H2S和CO2负荷最高，溶液的脱硫脱碳性能最好。继而在4套生产装置进行了推广应用。结论表明：应用MDEA/DEA混合溶液对低含硫、高含碳的天然气进行净化处理，溶液酸气负荷较高，脱硫、脱碳性能较好，腐蚀性小，天然气净化装置运行平稳，节能效果好，经济适用。

Application of the mixed MDEA/DEA desulphurization and decarbonization solution in some gas fields of Changqing Gas Zone

With the continuous development of Jingbian and other gas fields, the properties of the produced natural gas there have become greatly different, among which the content of H_2S increases up to 1000 mg/m~3 and the volume fraction of CO_2 in the gas has risen to 4.5% - 6.0%. Therefore, only the MDEA solution, which was commonly used in gas purification process before, can no longer meet the needs of desulphurization and decarbonization for the produced natural gas now in this area. Therefore, we performed tests on decarburization and desulfurization by the mixed MDEA/DEA solutions with different volume ratios. The results showed that, under the same testing condition, the mixed solution, in which the mass fraction of amine is 40%, the volume ratio of DEA and MDEA is 1:6, has the best desulphurization and decarbonization property. Besides, the H_2S load and CO_2 load of this mixed solution are the highest. Then we applied this mixed solution in four production facilities and found out that when the mixed solution is applied in the treatment of sweet gas with high carbon content, the sour gas load of the solution is higher and the effect of desulphurization and decarbonization is better; in addition, the corrosion is slight; and the natural gas purification facility runs smoothly with favorable energy-saving and economical performance.