N,N-二乙基乙醇胺(DEEA)溶液CO_2吸收解吸性能的实验研究

Experimental studies on sorption and desorption performance of CO_2 by N,N-diethylethanolamine(DEEA) solution

胺法捕集回收二氧化碳工艺存在的最大缺陷是高吸收速率与低再生能耗不能共存,高效溶剂的开发是解决这一问题的有效途径之一。为筛选出吸收解吸综合性能良好的吸收剂,本文利用溶剂快速筛选实验装置对几种不同醇胺吸收剂进行了实验研究,主要从溶液吸收负载、吸收速率、解吸负载、解吸速率、循环容量及相对再生能耗等方面进行了分析比较,实验结果显示N,N-二乙基乙醇胺(DEEA)溶液表现出较好的CO2捕获性能。此外,通过溶解度装置、填料吸收塔及再生塔分别对DEEA溶液的平衡溶解度、传质系数及再生能耗进行了实验研究与验证。实验结果表明:增加溶液浓度会降低其CO2平衡溶解度;增加CO2分压能增加其CO2平衡溶解度;增大进料温度能增加溶液在填料塔中的传质系数;提高富液负载及贫液负载会降低溶液的再生能耗。因此,基于其较好的吸收解吸性能,DEEA是一种可以工业化应用的潜在吸收剂。

The major drawback of using amine for carbon dioxide （CO2） capture is the contradiction between lower regeneration heat duty and high CO2 absorption rate. One way to overcome this problem is to develop an alternative absorbent with improved performance of sorption and desorption CO2, which can make energy consumption decrease. A quick method was used for selecting potential solvent systems for CO2 capture by experimental study in this paper. The analysis and comparison were made based on CO2 loading during sorption and desorption, the absorption/stripping rate, cycling capacity, relative heat consumption and so on. It is demonstrated that aqueous N,N-diethylethanolamine（DEEA） solution is of better absorption/stripping performance for CO2 capture, which can be presented in terms of equilibrium solubility, overall mass transfer coefficient（KGaV） and regeneration heat consumption, and these parameters were experimentally measured with relevant setup. The results show that the equilibrium solubility of CO2 in DEEA solution increases with rising of CO2 partial pressure and decreases with the increase of solution concentration; the KGaV increases with rising of liquid temperature and energy consumption; and the regeneration heat duty decreases with lean CO2 loading and increases with rich CO2 loading. Due to the high performance of DEEA, it could be a promising alternative solvent for CO2 capture.