煤制烯烃企业全厂能量系统优化策略及应用

Strategy and its application for the overall energy system optimization of coal to olefin plant

为了实现煤制烯烃企业全厂能量系统优化,提出了煤制烯烃企业全厂能量系统基于单元、子系统和全局划分的渐进协同优化策略,包括全厂用能状况分析、工艺装置用能及换热网络优化、低品位热回收和优化利用、全厂蒸汽动力系统优化等步骤。应用上述优化策略,对某60万t/a煤制烯烃企业全厂能量系统优化进行研究,得到全厂各单元能耗分布,提出了甲醇合成和甲醇制烯烃单元换热网络优化、全厂蒸汽动力系统降低蒸汽减温减压量及低品位热合理匹配利用等节能方案,理论上可以提高全厂系统能效3%以上,年节约标煤10万t以上,投资回收期小于1 a。

To optimize the overall energy system of coal to olefins plant,a progressive and collaborative strategy based on the unit,subsystem and global division is proposed for overall energy system optimization of coal to olefins plant.The whole plant energy consumption analysis,process equipment energy efficiency improvement,heat-exchanger network optimization,low grade heat recovery and utilization optimization and the whole plant steam and power system optimization were systematically studied.Based on the strategy,an overall energy system of a coal to olefins plant with 600 thousand tons olefin output per year was optimized.Energy consumption proportion for all processes was obtained,and some optimization schemes for saving energy were proposed. Accordingly,heat exchanger network of methanol synthesis and MTO units and steam decompression in the steam power system and rational utilization of low grade heat were thus optimized.Theoretically,it can improve the overall energy efficiency of more than 3%,save over 100 thousand ton standard coal,and achieve the investment recovery period of less than 1 year.The optimization strategy can provide reference for energy saving and emission reduction in the coal to olefin industry.