综合考虑泵的设备及运行费用的换热网络优化

Analysis of equipment and operating costs of the pump and optimization of heat exchanger network

流体流经换热设备产生的压降是影响换热网络综合的重要因素,且压降会对整个换热网络系统的稳态运行造成影响。因此在进行换热网络综合时,泵的设备购置费、运行泵的能耗费用需同换热设备费用和公用工程费用同时进行考虑。本文基于有分流的非等温混合分级换热网络超结构模型,并且去除流股给热系数为常数的假设,将流股的给热系数作为流股流速的函数,以换热网络最低年总费用作为本文数学模型的目标函数,综合考虑泵的设备购置费用和泵运行时的能耗费用,建立了一个换热网络同步综合的MINLP数学模型。采用改进的拟并行的遗传/模拟退火算法对该数学模型进行求解,可获得最优的压降值及最优流股给热系数下的换热网络结构。最后,通过具体的算例证明了模型的有效性和可靠性,达到了既简化换热网络结构又降低了年总费用的目标。

Pressure losses produced in streams flow through heat exchangers network is an important influencing factor of the heat exchangers network synthesis,and it also contributes to steady-state operation of the heat exchanger network. So the capital ＆amp; operating costs of pumps should be considered together with the costs of heat exchangers equipment and utilities. Based on the model of non-isothermal mixing of splits stage-wise heat exchangers network superstructure , this paper presented MINLP model for simultaneous synthesis of heat exchangers network,and the heat-transfer coefficients were considered as the function of the velocity of streams instead of as constants. The total annual cost of the heat exchangers network was chosen as the objective function,and the capital ＆amp;operating costs of pumps were also taken into consideration. The improved GA/SA was used to solve this mathematical model and optimal values of pressure drop and heat-transfer coefficients of streams were obtained. Finally,the validity and reliability of the proposed method were verified with an example,the objective to simplify the heat exchangers network and reduce the total annual cost of the heat exchangers network were achieved.