低温结晶净化柠檬酸盐解吸贫液中硫酸根

Removal of sulfate ion in citrate desorption lean solution

在柠檬酸盐吸收—解吸脱硫技术中,完成循环吸收过程的吸收液由于烟气杂质催化和高温解吸变成了含低二氧化硫浓度、中高硫酸根浓度、多种有机酸共存的柠檬酸盐解吸贫液,造成吸收效率下降、SO2平衡容量严重降低,必须进行溶液净化,特别是净化硫酸根。针对这一问题,实验室采用低温结晶法净化柠檬酸盐脱硫解吸贫液模拟液,通过对溶液中硫酸根浓度分析,研究了不同反应时间、温度、初始硫酸根浓度、柠檬酸根总浓度和溶液p H对硫酸根去除效率的影响。结果表明,硫酸根去除率与冷冻温度和溶液p H有关。在柠檬酸根总浓度1.5 mol/L,初始硫酸根浓度40 g/L,冷冻温度3℃,p H 4.5的条件下,可将硫酸根净化至16.9 g/L。

In the technology of citrate absorption-desorption desulfurization,the absorption solution which helps complete the cycling absorption process becomes citrate removal desorption barren solution with low concentration sulfur dioxide,medium or high concentration sulfate and various coexisting organic acid because of the catalysis of impurities in the exhaust gas as well as high temperature desorption. This will lead to the reduction of citrate absorption efficiency and SO2 equilibrium capacity. In order to purify the sulfate,low temperature crystallization technology is used in the lab to study the influence of factors such as different reaction times,temperatures,initial concentrations of sulfate,total concentration of citrate and solution p H on removal efficiency by analyzing the concentration of sulfate. The results show that removal efficiency of sulfate is related to freezing temperature and solution p H,and sulfate can be purified to 16. 9 g / L under the conditions of p H of 4. 5,temperature of3℃,total citrate concentration of 1. 5 mol / L and initial sulfate concentration of 40 g / L.