基于夹点技术的催化裂化装置的低温余热回收网络优化研究

在中国炼厂是能耗最大的工业企业之一，因此当前低温余热回收是炼厂节能的重要途径之一。本文以某炼厂催化裂化装置存在的低温余热为例，通过采用夹点技术进行低温余热回收网络的优化设计为MED选择出最佳的驱动热源。通过分析，冷热物流中存在相变化物流，故为避免忽略的潜热，首先进行对相变化物流进行处理，即物流被分成液相和气相两股物流对待。通过计算最佳的ΔTmin是26℃，在此ΔTmin下换热网络的成本费用最下为1.098×106$。通过问题表格法进行进一步分析，在夹点处热、冷物流的温度分别为119和93℃；在119℃之上，最小公用工程加热负荷QH,min为440457.64 kW；在93℃，所需的最小公用工程冷却负荷QC,min为1965993.85 kW。最后，换热网络设计采用夹点之上的设计和夹点之下2步分别优化，并得到最终的综合换热网络。

Optimizing Low-Temperature Heat Recovery in a Refinery Fluid Catalytic Cracking Unit Based on Pinch Analysis

In this paper, the research was focused on optimizing low-temperature heat recovery to adopt multi-effect distillation (MED) in desalination by pinch technology. And further analysis indicated that phase changes occurred during the heat recovery process. In such case, the feed stream was divided into two streams: the liquid feed stream and the gaseous feed stream. Through calculation, the optimal ΔTmin was established at 26 ℃, and the total cost of heat exchange process was only $1.098×106. By using the Problem Table Algorithm for pinch analysis, the temperature of the hot and the cold steams was 119 ℃ and 93 ℃, respectively. At a temperature higher than 119 ℃, all heat of the hot stream could not be cooled by the condenser, and the minimum heat load of utility (QH,min) was 440457.64 kW; and at a temperature below 93 ℃, all heat of the cold stream could not be provided by the heater, and the minimum cold load of utility (QC,min) was 1965993.85 kW. Finally, the synthesis of heat exchanger network was established through integrating two heat exchanger networks.