Abstract:

This paper firstly conducted the experiments of CO₂ capture from flue gas by vacuum pressure swing adsorption (VPSA) based on the two-bed experimental set-up using industrial silica as adsorbent. The mathematical model of VPSA process was built in gPROMS and its validity was well verified by comparing the results of simulation with experiment. The concentration of CO₂ can be enriched to 74% from 15% with recovery of 91.52% by the two-bed VPSA process. Based on the model, the relationship of product concentration, recovery, energy consumption of CO₂ with feed flowrate, adsorption time and blowdown pressure was investigated. The influence of bed pressure and feed flowrate on compressor energy consumption was also studied. Results showed that the concentration of CO₂ can be enriched significantly by increasing feed flowrate, extending adsorption time and decreasing counter-blowdown pressure, but all of them were companied with reduction in recovery and the former two led to a higher energy consumption. The higher in adsorption pressure and larger in feed flowrate, the more energy will the compressor consumed.

Key words: VPSA, flue gas, CO₂ capture, dynamic modeling, experimental validation, process analyzation

摘要：

采用工业硅胶作为吸附剂,利用两塔变压吸附装置进行了烟道气变压吸附碳捕集实验。利用gPROMS软件建立两塔变压吸附模型对实验过程进行模拟,对比了实验和模拟的结果,验证了模型的准确性。通过两塔变压吸附可将15%的CO₂富集到74%,收率为91.52%。在模型基础上考察了变压吸附碳捕集过程中进料量、吸附时间、顺放压力与二氧化碳收率、纯度和能耗的关系,定性分析了吸附塔压力和进料量对压缩机能耗的影响。结果表明:增大进料量、延长吸附时间、降低顺放压力,可以有效提高产品气中CO₂浓度,但同时也导致收率的下降,前两者还会造成单位能耗的增加;吸附压力越高,进料流量越大,压缩机能耗越大。

关键词: 变压吸附, 烟道气, 二氧化碳捕集, 动态模拟, 实验验证, 流程分析