LNG轻烃分离工艺热力学优化研究

Thermodynamic Optimization of Light Hydrocarbons Recovery Process From Liquified Natural Gas

为LNG冷能及其中轻烃组分更好的回收利用,结合国内及国外LNG轻烃分离工艺现有研究成果,提出一种优化的LNG轻烃分离工艺流程,运用Aspen Hysys进行模拟并对模拟结果进行?效率、功耗、产品常量及回收率等评价指标分析。结果表明:在脱烃LNG品质不下降的前提下运用冷能梯级利用技术使得改进流程功耗在原流程功耗基础上下降约7%,且使得改进流程?效率(51.6%)高于原流程?效率(45.58%)。但发现在LNG加压后原流程换热器与改进流程换热器?效率较低,分别为64%与46.12%。在原流程基础上新增脱乙烷塔分离得到可作为生产乙烯原料(产量3.34 t·h;)的乙烷及有及高价值的石化原料LPG产品(回收率96.82%),经经济性分析发现新流程在经济性方面要优于原专利流程。

In order to make better use of LNG cold energy and recover light hydrocarbon components in LNG,combined with the existing research results of domestic LNG light hydrocarbon separation technology, an optimized LNG light hydrocarbon separation process was proposed. Aspen Hysys was used to simulate the process, and the evaluation indexes of exergy efficiency, power consumption, product constant and recovery rate were analyzed. The results showed that through the use of cold energy cascade utilization technology under the premise that the quality of de-hydrocarbon LNG was not reduced, the power consumption of the improved process was reduced by about 83.1%based on the power consumption of the original process, and the exergy efficiency of the improved process(51.6%)was higher than that(45.58%) of the original process. However, it was found that the exergy efficiency of the original process heat exchanger and the improved process heat exchanger after LNG pressurization was lower, which were 64% and 46.12%, respectively. On the basis of the original process, a de-ethanizer was added to separate ethane that can be used as a raw material for the production of ethylene(output 3.34 t·h;) and high-value petrochemical raw material LPG product(recovery rate of 96.82%).