氧化铝生产蒸发工序能耗分析

Energy consumption analysis for evaporation process in alumina refinery

为降低氧化铝生产蒸发工序的能耗,对测试结果误差进行修正;应用热分析和分析方法研究四效蒸发器三级闪蒸器系统的用能状况。研究结果表明:蒸发系统的热效率仅为15.39%,其中Ⅳ效蒸发器的热效率仅为7.23%,其他单元热效率较高;Ⅳ效蒸发器的热损失主要是外排的冷凝水和乏汽带走大量的热所致;蒸发系统的效率仅为19.51%,其中各效蒸发器的效率均较低而损失率均较高,是提高系统效率的关键因素,因此,应加强乏汽和冷凝水的余热回收利用,并优化或改进蒸发器的操作参数和预热器使用方式。

In order to reduce energy consumption of evaporation process in alumina refinery, the errors of tested results were corrected, and thermal and exergy analysis were applied to study the four-effect evaporators and three-stage flashes evaporation system. The results show that the thermal efficiency of the evaporation system is only 15.39%, and the thermal efficiencies of other units are high in thermal efficiencies except for effect IV, which is only 7.23%. The heat losses in the evaporators of effect IV are large, which are mainly in the form of condensed water and exhausted vapor output. The exergy efficiency of the evaporation system is only 19.51%. The exergy utilizing ratios of the evaporators are low and losing ratios are high, respectively, which are the key factors for the improvement of the exergy efficiency of the evaporation system, thus waste heat recovery and utilization of condensed water and exhausted vapor should be enhanced, and the operating parameters in evaporators and usage ways about preheaters should be optimized.