α-半水脱硫石膏常压盐溶液法制备工艺及调晶剂技术机理研究
发布时间：2018-12-15 17:29
【摘要】：脱硫石膏是石灰石/石灰湿法烟气脱硫技术的主要产物。随着我国节能减排工作的持续进行,越来越多的火电厂安装了脱硫装置,脱硫石膏排放量迅猛增长。为防止大量脱硫石膏堆积如山,产生二次污染,高效利用脱硫石膏已经迫在眉睫。脱硫石膏形成于液相环境中,具有纯度高、品质稳定、湿态粉体等特点,非常适合于用常压盐溶液法来制备α-半水脱硫石膏。 采用常压盐溶液法将脱硫石膏制备成α-半水脱硫石膏,并利用调晶剂技术调节α-半水脱硫石膏晶体形貌。试验中发现,反应介质NaCl溶液浓度及反应温度对脱硫石膏的脱水反应进程及α-半水脱硫石膏晶体形貌有较大影响:较低的NaCl溶液浓度及反应温度下,脱硫石膏无法进行脱水,α-半水脱硫石膏无法生成;二水石膏脱水反应可以进行的最低NaCl浓度为10%,最低反应温度为92.5℃;此时二水石膏脱水反应速率较慢,所得α-半水脱硫石膏晶体尺度较大;随着NaCl溶液浓度及反应温度的增大,脱硫石膏脱水反应速率变快,但所得α-半水脱硫石膏晶体尺度随之变小。 在调晶剂技术应用研究中发现,有机酸调晶剂结构与调晶效果有很大关系。一元有机酸无调晶效果;二元及多元有机酸中,相邻羧基间距为3个C-C的调晶剂才具有较佳的调晶效果,而其他调晶剂则不具有调晶效果。二元有机酸调晶剂是通过两个羧基的协同作用产生调晶效果的,因此在双键存在的条件下,由于反式结构中的两个羧基协同作用较顺式结构更为困难,其调晶效果较顺式结构要弱。 调晶剂的作用机理一直是一个难以解决的问题。通过SEM及EDS、XPS等手段,直接证明了有机酸调晶剂通过化学吸附作用于α-半水脱硫石膏晶体(111)面,从而阻碍α-半水脱硫石膏在C轴方向上的生长,改变α-半水脱硫石膏晶体的生长习性,平衡α-半水脱硫石膏在各个方向上的生长速率,达到调节α-半水脱硫石膏晶体形貌的效果。同时发现,无机盐类调晶剂对常压盐溶液法制备α-半水脱硫石膏无影响,金属离子不会吸附于α-半水脱硫石膏晶体(111)晶面上,也不会吸附于α-半水脱硫石膏晶体(110)晶面上。在有机酸与无机盐调晶复合作用下,起调晶作用的仍然只是有机酸调晶剂。
[Abstract]:Desulphurized gypsum is the main product of limestone / lime wet flue gas desulfurization technology. With the development of energy saving and emission reduction in China, more and more thermal power plants have installed desulphurization units, and the emissions of desulfurized gypsum are increasing rapidly. In order to prevent a large amount of desulphurized gypsum from accumulating and producing secondary pollution, it is urgent to utilize desulfurized gypsum efficiently. Desulphurized gypsum is formed in liquid environment and has the characteristics of high purity, stable quality and wet powder. It is very suitable for preparing 伪 -hemihydrate desulphurization gypsum by salt solution under normal pressure. The desulfurized gypsum was prepared by normal pressure salt solution method, and the crystal morphology of 伪 -hemihydrate desulphurization gypsum was adjusted by crystal adjusting agent. It is found that the concentration of NaCl solution and reaction temperature have great influence on the dehydration process of desulfurized gypsum and crystal morphology of 伪 -hemihydrate desulphurization gypsum. At lower NaCl solution concentration and reaction temperature, desulfurization gypsum cannot dewatering. 伪-hemihydrate desulphurization gypsum can not be formed; The lowest NaCl concentration and reaction temperature are 10 and 92.5 鈩，
本文编号：2381029
[Abstract]:Desulphurized gypsum is the main product of limestone / lime wet flue gas desulfurization technology. With the development of energy saving and emission reduction in China, more and more thermal power plants have installed desulphurization units, and the emissions of desulfurized gypsum are increasing rapidly. In order to prevent a large amount of desulphurized gypsum from accumulating and producing secondary pollution, it is urgent to utilize desulfurized gypsum efficiently. Desulphurized gypsum is formed in liquid environment and has the characteristics of high purity, stable quality and wet powder. It is very suitable for preparing 伪 -hemihydrate desulphurization gypsum by salt solution under normal pressure. The desulfurized gypsum was prepared by normal pressure salt solution method, and the crystal morphology of 伪 -hemihydrate desulphurization gypsum was adjusted by crystal adjusting agent. It is found that the concentration of NaCl solution and reaction temperature have great influence on the dehydration process of desulfurized gypsum and crystal morphology of 伪 -hemihydrate desulphurization gypsum. At lower NaCl solution concentration and reaction temperature, desulfurization gypsum cannot dewatering. 伪-hemihydrate desulphurization gypsum can not be formed; The lowest NaCl concentration and reaction temperature are 10 and 92.5 鈩，
本文编号：2381029
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