机械蒸汽再压缩硫酸铵废水处理系统的分析

为全面反应机械蒸汽再压缩硫酸铵废水处理系统的用能情况,提高系统的效率,采用以热力学第二定律为基础的分析方法,对系统进行了分析。将硫酸铵废水视为实际溶液,建立了实际物流的分析模型,运用工厂实测数据对系统进行了分析计算,研究了参量:压缩比、蒸发温度和一效排出浓度对系统效率的影响并根据测算结果提出了改进建议。分析结果表明,该系统总的效率约为12.04%;各设备分析表明,换热器及压缩机是主要的损失部位,二者的损失约占总数的79.5%;参量分析表明,系统的效率随着压缩比的增大而减小,随着蒸发温度的升高而增大,在其他条件允许的情况下,应尽量采用压缩比小的压缩机和维持高的蒸发温度;在文中条件下,当一效排出质量分数为32%时系统的效率最大,应尽可能地维持在该质量分数下排料;消除进入加热器蒸汽的过热可以提高系统的效率。

Exergy analysis of system for ammonium sulfate wastewater treatment with mechanical vapor recompression

In order to reflect the exergy of mechanical vapor recompression(MVR) ammonium sulfate wastewater treatment system and improve the system efficiency,the system was analyzed by the exergy method based on the second law of thermodynamics.The exergy methods were built up with the ammonium sulfate wastewater as actual solution.By using the actually measured operational data,the system was analyzed.The effects of parameters such as compression ratio,evaporation temperature and discharging concentration of one-effect,on exergy efficiency were studied and some proposals to improve the efficiency were put forward.The results show that the total exergy efficiency of the system is about 12.04%,the exergy losses of heat exchangers and compressors are the most and the exergy losses of them share about 79.5%.The parameters analysis shows that the system exergy efficiency decreases with compression ratio increasing and increases with evaporation temperature rising.Under the permission conditions,smaller compression ratio compressor and higher evaporation temperature should be used;under the conditions in this work,exergy efficiency is the maximum when the discharge mass concentration of one-effect is about 32%,so discharging feeds should be maintained at its mass concentration.The exergy efficiency can be raised by eliminating steam superheat.