石化企业蒸汽使用系统分步操作优化

Operational Optimization of Steam Using System in Petrochemical Plant

大型的石化企业中,蒸汽使用系统将来自锅炉的新鲜蒸汽转化为工艺系统需要的电力和一定压力的蒸汽,蒸汽使用系统蒸汽分配效率的高低直接关系着整个石化企业的能源利用率。蒸汽使用系统中汽轮机的热效率不同,背压汽轮机的热效率最高,并且在满足用户对热量需求的同时能副产电力。文章依据背压汽轮机的的特点,提出了蒸汽动力系统的分步优化方法:用户对蒸汽的需求优先使用背压汽轮机排气提供,同时最大限度副产电力;对电力的需求不足部分由凝气轮机满足,建立分步优化的模型。使用分步优化模型对某石化企业蒸汽动力系统进行优化,结果比使用一步优化方法的优化结果节能效果更显著。

Steam and power system is the core of the utility system of a petrochemical plant, which provides steam and power for the production process. In the same time, steam and power system consumes a great quantity of energy, and has significant impact on the energy utilization efficiency of a petrochemical plant. The thermal efficiency of backpressure turbine is highest, and could provide power while meeting the need of steam; a two-step optimization model is established in the paper. First step, satisfying heat demand using backpressure turbine and producing power as much as possible. Second step, using condensing steam turbines to compliment power shortfall. Then a steam and power system of a certain petrochemical plant is optimized using the two-step model. The result shows that two-step optimization method has a better steam saving effect than one-step optimization method.