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研究报告

Recovering carbon dioxide from flue gas by diethylene triamine (DETA) and K₂CO₃ solution

摘要：热钾碱溶液在工业脱除二氧化碳中已获得较广泛的应用,但存在吸收速率差、再生负荷高等缺点.开发新型热钾碱溶液成为目前研究热点.采用搅拌实验装置,研究碳酸钾溶液及不同配比的碳酸钾-二乙烯三胺(DETA)复合溶液对烟道气中二氧化碳的吸收和解吸性能,揭示了吸收速率、吸收容量和酸碱度与时间之间的内在联系;对CO₂初始逸出温度,试液再生温度,试液再生率,再生pH下降率进行了细致记录分析.实验结果表明,碳酸钾-DETA二元复合体系吸收效果优于单组份碳酸钾的吸收效果.碳酸钾-DETA复合溶液配比为0.6 ∶ 0.4时吸收效果最佳,吸收量约为0.80 mol · L^-1;再生温度最低,为107 ℃;再生率最高,为95.5%.同时与相同配比的碳酸钾-一乙醇胺(MEA)、碳酸钾-二乙醇胺(DEA)相比具有较大再生优势.实验结果还表明碳酸钾-DETA复合体系在二氧化碳吸收过程中存在正交互作用.

Abstract：Hot alkaline solutions of potassium salts have been widely used for removing carbon dioxide in industry, but they have disadvantages of poor absorption rate and high regeneration load. So developing new types of thermal alkaline potassium solutions is important. A series of experiments was performed to study the absorption and desorption of carbon dioxide from flue gas with potassium carbonate solution and different proportions of potassium carbonate-DETA (diethylene triamine) complex solution. The relationships between absorption rate, absorption capacity, pH and time were determined by analyzing the initial escape temperature of CO₂, the regeneration temperature, regeneration rate, and pH decline during regeneration. The experimental results show that the best absorption effect (in which the absorption capacity was 0.80 mol · L^-1) was obtained using a binary complex system 0.6 ∶ 0.4 K₂CO₃ ∶ DETA. The highest regeneration rate was about 95.5% at the lowest regeneration temperature, 107 ℃. Compared with potassium carbonate-MEA(ethanolamine) and potassium carbonate-DEA ( diethanolamine ), the potassium carbonate-DETA system (with the same molar ratio) can be more effectively regenerated. A positive interaction occurs between potassium carbonate and DETA solution during the process of absorption of carbon dioxide.