Abstract: A new ammonia recovery process of absorption and multi-stage flash distillation with ionic liquid [C4mim]BF4 as absorbent was designed, simulated and optimized. NRTL activity coefficient model was adopted, vapor-liquid equilibrium (VLE) data of ammonia and methane in the ionic liquid [C4mim]BF4 were regressed. The results showed that the NRTL model could correlate and predict the binary VLE systems containing ionic liquid well. Sensitivity analysis with Aspen Plus software was used to optimize the process, the effects of flow rate and temperature of absorbent on the molar concentration of ammonia in the purified gas were analyzed. The results showed that increasing the flow rate and reducing the temperature were conducive to the absorption of ammonia by [C4mim]BF4, the optimized operating conditions were mass flow rate 2000 kg/h and 30℃. The molar concentrations of ammonia in purified gas and the regenerated gas were 32.4′10-6 and 95.2%, meeting the design requirements, and energy consumption for per ton ammonia in this process was 940 kg standard coal, saving 200 kg standard coal, compared with the traditional process.

Key words: ammonia recovery, [C4mim]BF4, absorption, flash distillation, simulation, optimization

摘要： 设计并模拟优化了以[C4mim]BF4离子液体为吸收剂的吸收与多级闪蒸回收氨的工艺，采用NRTL活度系数模型对氨和甲烷在[C4mim]BF4中的气液平衡数据进行拟合，结果表明，该模型能很好地关联和预测含离子液体的二元体系气液平衡. 应用Aspen Plus软件灵敏度分析模块，对吸收剂流量、温度进行了灵敏度分析和优化，结果表明，增大流量和降低温度有利于[C4mim]BF4对氨的吸收，优化操作条件为流量2000 kg/h、温度30℃. 该回收工艺净化气和再生气中氨摩尔浓度分别为32.4′10-6和95.2%，满足设计要求，标准煤耗预计为940 kg/t，比传统工艺节能200 kg/t.

关键词: 氨回收, [C4mim]BF4, 吸收, 闪蒸, 模拟, 优化