闭式热泵技术辅助汽提精馏脱氨工艺优化与分析

Optimization and analysis of closed-cycle heat pump-assisted steam-stripping distillation deamination process

汽提精馏脱氨工艺因具有效率高、稳定且处理后废水氨含量低等优点,是国家工信部推荐的高质量浓度氨氮废水处理技术。采用闭式热泵技术安全、稳定的回收利用塔顶含氨蒸汽热量,可有效降低过程的蒸汽消耗,解决常规汽提精馏脱氨工艺能耗高的缺点。文中依据已在锂离子电池三元前驱体生产中工业化实施的闭式热泵辅助汽提精馏脱氨工艺,模拟比较常规汽提精馏脱氨工艺和闭式热泵辅助工艺,并以年度总费用C_(TA)为目标函数进行了工艺优化。结果表明:闭式热泵辅助工艺相较于常规汽提精馏脱氨工艺,虽然设备投资成本明显增加,但年度运行成本却减少41.90%,因而,5 a回收期的C_(TA)可减少18.08%,二氧化碳排放量可减少42.16%,具有显著的经济和社会效益。

The steam-stripping distillation deamination process is the recommended technology by the Ministry of Industry and Information Technology for treating high mass concentration ammonia-nitrogen wastewater with the advantages of high efficiency,good process consistency,and low ammonia content in the after-treated wastewater.The introduction of closed-cycle heat pump technology into the process can safely and stably recover the latent heat of overhead ammonia-containing steam,significantly reducing the energy consumption of the conventional steam-stripping distillation process.Based on an industrialized steam-stripping distillation deamination process in the production of ternary cathode material precursors for lithium-ion batteries,a closed-cycle heat pump-assisted steam-stripping distillation deamination process was simulated and optimized by using the total annual cost C_(TA)as the objective function.The results show that compared with the conventional process,the closed-cycle heat pump-assisted process exhibits significant economic and energy-saving benefits.Although total capital cost is significantly increased,the annual operating cost can be decreased by 41.90%,the resulted C_(TA)(5-year payback period)is decreased by 18.08%,and CO 2 emissions is lowered by 42.16%.