乙二胺/磷酸溶液化学吸收法烟气脱硫的研究  

Chemical Absorption of SO_2 by Using Ethylene Diamine/Phosphoric Acid Solution

作　　者：汤志刚[1] 周长城[1] 陈成[1] 

机构地区：[1]清华大学化学工程系,北京100084

出　　处：《高校化学工程学报》2005年第3期285-291,共7页Journal of Chemical Engineering of Chinese Universities

摘　　要：提出了一种有机胺吸收二氧化硫的新型烟气脱硫工艺,并建立了有机胺吸收烟气中二氧化硫的气液平衡模型,首次较好预测了二氧化硫-乙二胺-磷酸水溶液体系的气液平衡.对比0.3mol·L-1乙二胺缓冲溶液的预测结果与实验结果,最大相对偏差不超过7%.同时,以乙二胺/磷酸混合溶液作为吸收剂,在φ 30mm×600mm的填料塔中进行了逆流吸收和解吸实验,确定了实验室规模下适宜的吸收工艺条件:液气比L/G=0.6～1.0 L·m-3,乙二胺浓度0.3 mol·L-1,吸收液初始SO2浓度4～6g·L·1,pH值6.0～7.5;解吸工艺条件为:预热温度60℃,塔釜温度103℃,喷淋密度0.7m3·m-2·h-1,富液中SO2浓度14～16 g·L-1.进一步的经济分析表明,乙二胺/磷酸法脱硫费用相当于石灰石法的1/3,低于氨法和新近开发的NADS法,具有较好的经济性.A novel FGD process was proposed, in which organic amine is used as absorbent to absorb the sulfur dioxide in flue gas. The vapor-liquid equilibrium model of absorption of sulfur dioxide in flue gas by organic amine was established, and the vapor-liquid equilibrium of sulfur dioxide-ethylene diamine-phosphoric acid-water system was predicted. Comparing the predicted results with the experimental results for a 0.3 mol&middotL-1 ethylene diamine-phosphoric acid solution system, the relative error is less than 7 percent. By using ethylene diamine/phosphoric acid aqueous solution as absorbent and a φ30 mm × 600 mm packed tower in the lab, the suitable technical conditions of SO2 absorption and deabsoption were experimentally searched. Results show that the suitable conditions are as following: for absorption; the ratio of liquid to gas L/G is 0.6-1.0 L&middotm-3, concentration of ethylene diamine in absorbing solution is 0.3 mol&middotm-1, residual SO2 concentration in the desorbed liquid used as absorbent is 4-6 g&middotL-1, pH value is 6.0-7.5; for deabsorption; the feed temperature is 60°C, the bottom temperature of the deabsorption tower is 103°C, liquid flow rate is 0.7 m3 &middot m-2 &middot h-1, and the concentration of SO2 in the feed-in liquid is 14-16 g&middotL-1. Several wet FGD methods for a 200 MV power plant were economically analyzed and compared. Unit FGD expense of the proposed novel method is one third of that of limestone-gypsum method and is also lower than that of Ammonia method and NADS method.

关 键 词：烟气脱硫 二氧化硫 有机胺 吸收 气液平衡 

分 类 号：X701.3[环境科学与工程—环境工程] TQ028.17[化学工程]