PZ活化MDEA乙烷深度脱碳工艺研究

Ethane deep decarbonization process with PZ activated MDEA

关键词:  PZ  活化MDEA  乙烷脱碳  能耗优化  Aspen HYSYS 

Key words:  piperazine  activated MDEA  ethane decarburization  energy consumption optimization  Aspen HYSYS

摘要:

目的 解决醇胺法乙烷脱碳工艺造成的乙烷损失量较大和装置能耗较高等问题。方法 用Aspen HYSYS软件对某乙烷回收流程的粗乙烷产品进行胺法脱碳模拟,在控制乙烷损失物质的量比小于0.3%的情况下对胺液中的PZ和MDEA质量分数进行了优选,同时对乙烷脱碳流程进行能耗优化。结果 与天然气脱碳工艺不同,乙烷脱碳工艺的MDEA质量分数太高会损失大量乙烷。在达到脱碳效果的前提下,较低的MDEA质量分数可避免损失大量乙烷,最佳MDEA质量分数为20%~28%。在此MDEA质量分数的条件下,可保证乙烷损失比仅为0.3%,往胺液中加入少量哌嗪(PZ)就可显著提高胺液对CO₂的吸收效果,最佳PZ质量分数为2.5%~5.5%。乙烷脱碳装置的主要能耗为胺液再生能耗,优化后装置的总能耗显著降低。结论 在工业条件下,应用较低质量分数的胺液可显著降低乙烷损失,可合理提高富胺液入再生塔温度或适当降低脱碳溶液循环量,以降低装置能耗。 

Abstract:

Objective sThe aim is to solve the problems of large ethane loss and high energy consumption of the unit caused by the alcohol amine method ethane decarburization process. Methods Aspen HYSYS software was used to simulate the amine method decarbonization of crude ethane products in an ethane recovery process, and the mass fraction of PZ and MDEA in the amine solution were optimized under the condition that the ethane loss ratio(calculated by molar flow) was controlled to be less than 0.3%. At the same time, the energy consumption of the ethane decarbonization process was optimized. Results Different from the natural gas decarburization process, if the MDEA mass fraction of the ethane decarburization process is too high, a large amount of ethane will be lost. On the premise of achieving decarbonization effect, the lower MDEA mass fraction could avoid the loss of a large amount of ethane.The best MDEA mass fraction was 20%-28%. Under this MDEA mass fraction, low concentration amine liquid could ensure that the ethane loss ratio was only 0.3%. Adding a small amount of piperazine(PZ) to the amine liquid could significantly improve the absorption effect of amine liquid on CO₂. The best PZ mass fraction was 2.5%-5.5%. The main energy consumption of ethane decarbonization unit was amine regeneration energy consumption. After optimizing, the total energy consumption of the unit was significantly reduced. Conclusion sUnder industrial conditions, the application of amine solution with lower mass fraction can significantly reduce the loss of ethane, and the energy consumption of the unit can be reduced by reasonably increasing the temperature of rich amine solution entering the regeneration tower or by appropriately reducing the circulating volume flow of decarbonization solution.