Waste heat recovery for wet flue gas desulfurization (WFGD) system is quite necessary so that both heat and water consumption can be saved. However, formerly, there existed no clear concept about the upper limit quantity of waste heat that can be recovered for a target WFGD system, and where the final operation status of WFGD system after waste heat recovered will be located is also absent. Therefore, in the current paper, a methodology is developed first to simulate the magnesium method desulfurization system with circulating water considered using Aspen Plus V8.4. After validation, the methodology with slight modification is then used to investigate the theoretical maximal quantity of waste heat that can be recovered under different conditions and study the corresponding variation tendencies of updated thermal and water equilibrium states. Desulfurization efficiency is also discussed qualitatively. Results indicate that there exist maximal 1.41 to 2.27 MW heat that can be recovered at WFGD system for an 80 t/hr coal‐fired boiler, equivalent to save standard coal from about 1,385 to 2,230 t/a. All the streams temperature are reduced after recovering waste heat, but different streams behave different variation tendency. Water consumption and desulfurization efficiency also could get improved.

中文翻译：

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从湿法烟气脱硫系统回收余热后的水和水平衡及脱硫效率分析

湿法烟气脱硫（WFGD）系统的废热回收非常必要，这样可以节省热量和水。然而，以前，对于目标WFGD系统可以回收的废热的上限数量尚无明确的概念，并且也没有将WFGD系统在废热回收后的最终运行状态定位的位置。因此，在当前的论文中，首先开发了一种方法，以考虑使用Aspen Plus V8.4的循环水对镁法脱硫系统进行模拟。验证后，将使用稍作修改的方法研究可在不同条件下回收的理论最大废热量，并研究更新的热平衡和水平衡状态的相应变化趋势。定性地讨论了脱硫效率。结果表明，对于80 t / hr的燃煤锅炉，WFGD系统最多可回收1.41至2.27 MW的热量，相当于节省标准煤约1,385至2,230 t / a。回收废热后，所有物流的温度均降低，但不同的物流表现出不同的变化趋势。耗水量和脱硫效率也可以得到提高。