中文摘要：

石化工艺装置在工艺和流程优化的基础上,通过夹点分析可以确定换热网络的最小热、冷公用工程量;同时,为增加装置热能回收利用效率,通常利用夹点之下的余热生产相应压力等级的蒸汽。但是,在工程实践中,由于石化装置冷物流的分流限制,导致夹点之上的热量并不能全部用于加热冷物流,不可避免的引起热量穿越夹点换热。基于夹点技术,建立流股受分流约束的换热网络混合整数线性规划模型。将建立的模型应用于某延迟焦化装置,通过模型求解,获取不可避免的穿越夹点的换热量,指出在夹点附近处冷、热流股的合理匹配方案,并对比分析受流股分流限制和不受流股分流限制的冷、热公用工程,结果表明建立的模型能够为石化工艺装置换热网络设计或改造提供技术支持。

英文摘要：

Finch analysis can be used to target the minimum hot and cold utilities of heat exchanger network（HEN） when the stream data are determined in a petrochemical unit where the processes and flowsheets are optimized firstly.The surplus heat duty below the pinch point are recovered and used to generate steam in order to increase the efficiency of energy utilization.However,in engineering practices,the heat duty above the pinch point cannot be totally employed to preheat the cold streams above the pinch point only because of the limitation of cold stream splitting.As a result,the heat duty above the pinch point must cross the pinch point for heat transfer.A mixed integer linear programming（MILP） model is presented here to target the minimum utility requirements where the cold stream is prohibited splitting.The MTLP model is applied to a delayed coking unit,and the solution results indicate the inevitable heat duty crossing pinch point and the reasonable match for heat transfer.Additionally,the minimum utility requirements with the limitation of stream splitting are compared with that without the limitation of stream splitting.The application indicates that the presented model can give a technical support for the design and retrofit of HEN.