关键词: CO₂捕集, 再生能耗, 压缩式热泵, 节能技术, 模型, 优化

Abstract:

The alcohol-amine method is a mature CO₂ capture technology, which has the advantages of high absorption speed and good removal effect, but its operation cost is high and desorption energy consumption is large. Therefore, based on reducing regeneration energy consumption of CO₂ capture system in flue gas by amine method, the energy saving of conventional CO₂ capture system by amine method was studied in this paper. Based on the energy-saving research of conventional amine CO₂ process, the energy-saving technology of compressed heat pump was introduced, and the CO₂ capture process model based on compressed heat pump technology was established by Aspen Plus software. The coupling of compressed heat pump with MVR heat pump, split-flow desorption, distributed heat transfer and inter-stage cooling was studied. By simulation and optimization, the optimal energy-saving process combination was finally obtained as CO₂ capture process of “desorption tower compressed heat pump+lean-liquid MVR heat pump+split-flow desorption + inter-stage cooling” coupling. When the split-flow ratio of top gas of desorption tower was 1/3, the split-flow ratio of rich and cold liquid was 0.05. The inter-stage cooler was located on 17 trays of the absorption tower. When the input cooling capacity of the absorption tower was -3.0GJ/h, the regeneration energy consumption of the system was the lowest, which is 2.533GJ/t CO₂. Compared with the conventional organic amine process, the energy saving rate was 39.748%.

Key words: CO₂ capture system, regeneration energy consumption, compressed heat pump, energy saving technology, model, optimization