高含CO2天然气脱碳工艺中MDEA活化剂优选

国内高含CO_2天然气处理装置主要采用活化MDEA脱碳工艺。以DEA、MEA、PZ为活化剂,总胺物质的量浓度控制在4 mol/L。利用HYSYS软件建立运算模型,研究这3种活化MDEA溶液对CO_2的吸收性能和解吸性能,通过分析认为,高含CO_2天然气深度脱碳处理宜采用PZ为活化剂。对PZ的活化机理进行研究,发现PZ作为活化剂的效果远胜于DEA和MEA。最后,分析不同吸收温度及CO_2分压下PZ浓度变化对活化性能的影响,发现加入少量PZ即可大幅提高PZ活化MDEA溶液与CO_2反应速率,在不同CO_2分压和吸收温度的条件下均能满足高含CO_2天然气的脱碳处理要求,适应性较强,建议活化MDEA溶液中PZ的质量分数为3%~5%。

MDEA activator optimization for decarbonization process of high CO2-containing natural gas

Activated MDEA decarbonization process was mainly adopted in natural gas processing plant with high CO₂ content in China. Using DEA, MEA, PZ as activators, the total amine molar concentration was controlled to 4 mol/L. The computing model was built with HYSYS software to study the CO₂ absorption and desorption performance of the three activated MDEA solutions. It was concluded that PZ was suitable to be used as the activator in the deep decarburization treatment of natural gas with high CO₂ content. The research on the activation mechanism of PZ showed that activated effect of PZ was far better than that of DEA and MEA. At last, the influence of PZ concentration on the activation performance was analyzed under different absorption temperature and CO₂ partial pressure. It was found that the addition of a small amount of PZ could greatly improve the reaction rate of PZ-activated MDEA solution with CO₂. It has strong adaptability to meet the decarburization treatment requirement of natural gas with high CO₂ content under different CO₂ partial pressure and absorption temperature. The recommend mass fraction of PZ in activated MDEA solution was 3wt%-5wt%.