扰动换热网络负荷迁移规律及瓶颈辨识策略  

Load-shift laws and bottleneck identification strategy of disturbed heat exchanger network

作　　者：赵丽文 刘桂莲[1] ZHAO Liwen;LIU Guilian(School of Chemical Engineering and Technology,Xi’an Jiaotong University,Xi’an 710049,Shaanxi,China)

机构地区：[1]西安交通大学化学工程与技术学院,陕西西安710049

出　　处：《化工学报》2023年第11期4611-4621,共11页CIESC Journal

基　　金：国家自然科学基金项目(22078259)。

摘　　要：对于发生源/阱参数变化的换热网络(HEN),提出一种系统的干扰响应/参数调整方法,用于平衡系统盈余热量/冷量,辨识制约能量回收的瓶颈及对应的解瓶颈策略。在拓扑结构分析基础上,枚举可行的响应对象及扰动传播路径,明确换热器的负荷转移规律。推导了换热器热阻需求(Rreq)、面积增量(?A)、系统年度总成本(Ct)与热容流率波动系数(α)之间的关系。构建热阻需求变化趋势图和经济变化图,以成本最优为目标,选择最佳的响应对象并确定其热负荷变化值,定位响应变量调整过程中因热阻制约而产生系统用能瓶颈,确定解瓶颈所需的面积增量。该方法无须复杂模拟计算即可确定扰动状态下加热/冷却介质流量需求变化值及各换热设备面积需增量,可以有效指导生产工艺的设计、优化和改造。以苯烷基化生产过程为例展示该方法的应用,当α位于[0.75,0.88]和[0.88,1.35]时,两台加热器分别是最优的响应对象,最大节省年度总成本19400 USD·a^(-1)和24024 USD·a^(-1)。For the heat exchanger network(HEN)with source/sink parameter variation,a systemic disturbance response/parameter adjustment method is proposed to maintain the heat balance of the system,identify the bottleneck restricting energy recovery and propose corresponding debottlenecking strategy.Based on topology analysis,feasible response objects and disturbance propagation paths of the system are enumerated,and the loadshift laws of heat exchangers are clarified.The relationship between heat exchanger thermal resistance requirement(Rreq),area increment(ΔA),total annual system cost(Ct)and heat capacity flow rate fluctuation coefficient(α)is derived.The thermal resistance demand change trend diagram and economic change diagram are constructed.With the optimal cost taken as the goal,the best response object is selected,and its heat load change value is determined.The system energy bottleneck caused by thermal resistance restriction during the adjustment of the response variable is located,and the area increment required to solve the bottleneck is determined.The proposed method can determine the change of the heating/cooling medium’s flow rate and that of each heat exchanger’s area demand under the disturbance state without complex simulation calculation,which is intuitive and efficient and can guide the design,optimization,or retrofit of chemical processes.A benzene alkylation process is analyzed to illustrate its application.Whenαlocates in the interval[0.75,0.88]and[0.88,1.35],two heaters are the optimal response objects,saving the total annual cost up to 19400 USD∙a^(-1) and 24024 USD∙a^(-1),respectively.

关 键 词：换热网络 扰动 负荷迁移 瓶颈 解瓶颈 

分 类 号：TQ021.8[化学工程]