基于中间换热器-吸收式热泵精馏节能系统的优化

为提升精馏环节的能源利用效率，基于高效回收换热器余热和梯级用能的理念，提出了设置中间换热器与吸收式热泵相结合的精馏节能系统；以某石化企业180 kt/a气体精馏“三塔”（脱丙烷塔、脱乙烷塔、丙烯精制塔）系统中的脱丙烷塔为研究对象，采用Aspen Plus建立数学模型，对中间换热-吸收式热泵精馏节能系统的中间再沸器、中间冷凝器以及热泵的操作参数进行优化，并对“三塔”精馏流程的节能效果进行分析。结果表明，采用中间换热-吸收式热泵精馏节能系统可将脱丙烷塔的蒸汽消耗量降低25%；对于完整“三塔”精馏流程，蒸汽消耗量可降低38.8%，循环冷却水用量节约42.5%，新增利润约530.8万元/a，项目静态投资的回收期为3 a。

OPTIMIZATION OF ENERGY-SAVING DISTILLATION SYSTEM BASED ON INTERMEDIATE HEAT EXCHANGER-ABSORPTION HEAT PUMP

In order to improve the energy efficiency of distillation, an energy-saving distillation system with an intermediate heat exchange and an absorption heat pump was proposed. The mathematical model of 180 kt/a gas distillation column in a petrochemical enterprise was established by using Aspen Plus software. The operating parameters of the intermediate reboiler, the intermediate-condenser and the absorption heat pump in the energy-saving system of the intermediate heat exchange-absorption heat pump distillation were optimized, and the energy-saving effect of the “three-column” distillation process was analyzed. The results show that the steam consumption of the depropane column can be decreased by 25% by using the intermediate heat exchange-absorption heat pump distillation energy saving system, the steam consumption can be reduced by 38.8%, and the softened water consumption can be saved by 42.5% for the complete three-column gas fractionation process. The additional profit is about 5 308 000 Yuan/a, and the fixed investment payback period of the project is about 3 years.