基于实际热负荷分布的换热网络优化改造

采用非等温混合分流分级超结构，建立了基于实际热负荷分布的换热网络改造模型，以由改造费用和运行费用组成的年度化总成本为目标，并采用遗传算法进行求解。改造费用涉及现有换热器增加换热面积、配置新换热器、重新布置管道以及移动现有换热设备所产生的费用，充分考虑了原有换热网络经改造后结构的变化所引起的改造成本。在回用原有换热设备后，根据设备实际面积来计算换热网络的热负荷分布和温度分布，即基于实际热负荷分布对换热网络进行改造。案例研究表明，改造后的换热网络结构具有良好的节能效益，合理地再利用了原网络中的旧换热设备，并以较少的改造成本实现了较高的能量回收，投资回报期仅为0.43年，验证了所提改造方法的有效性和实用性。

Optimization of heat exchanger network retrofit based on actual heat load distribution

The heat exchanger network retrofit model based on actual heat load distribution was established. The stage-wise superstructure model with non-isothermal takes into account the trade-offs between operation cost and retrofit cost involving the cost of increasing area of the existing heat exchangers, configuring new heat exchangers, repiping the streams and moving the existing heat exchangers. The differences between original heat exchanger network and structure after retrofitting were taken into account. Meanwhile, the deviations between the existing equipment area and the required area were also averted. Heat load distribution of heat exchanger network was calculated according to actual heat transfer area after the recycle of existing equipment. The genetic algorithm was applied to optimize heat exchanger network structure. Result indicated that structure of heat exchanger network after retrofitting has outstanding energy-saving benefits and more energy recovery with lower modification cost, all over a short return on investment of only 0.43 years. Moreover, the effectiveness and practicality of the proposed method were demonstrated.