资源描述
无机盐工业
第42卷第2期
36
INORGANIC CHEMICALS INDUSTRY
2010年2月
工业技术
在并/逆流喷雾蒸发器中浓缩净化磷酸的研究
权晓威,赵淑贤,李富强,刘钟海
(四川大学化工学院,四川成都610065
摘要:为获得较高浓度磷酸以满足对磷酸使用和运输的要求,采用正交实验和单因素实验对净化稀磷酸进
行了喷雾蒸发浓缩的系统实验研究。实验结果发现:影响净化稀僯酸蒸发浓缩效果的因素由主到次依次为稀磷酸
流量、熱风进门流量、二次风比例、热风进口混度、喷嘴气液比;浓缩的效果正比于热风进口流量、热风进口温度、稀
磷酸流量的倒数,且在喷嘴气液质量比大于0.8时受其影响不大;二次风的引入对稀磷酸浓缩不利。在实验装置
上经喷雾浓缩,成功获得了质量分数不低于85%的浓磷酸,并发现相应的热风出口温度不官低于110℃。由此可
见,通过喷雾蒸发浓缩得到较高浓度的磷酸是可行的
关键词:磷酸;嚙雰蒸发;喷嘴气液比
中图分类号:TQ126.35文献标识码:A文章编号:1006-4990(2010)02-0036-04
Study on concentration and purification of phosphoric acid in co/counter-current evaporator
Quan Xiaowei, Zhao Shuxian, Ii Fuqiang, Liu Zhonghai
School of Chemical Ergineering, Sichuan University, Chengdu 610065, China)
Abstract: Systematically experimental study on spray evaporation to concentrate purified phosphoric acid has been car
ried out by orthogonal and single-factor experiments in order to attain highly concentrated phosphoric acid to achieve the
quality requirement of utilization and transport of it. Results showed that the factors influencing evaporation concentration ef
ficiency of dilute purified phosphoric acid, according to the importance of which, were dilute phosphoric acid flow rate, inlet
heated air flow rate, ratio of secondary air, inlet heated air temperature, and gas to liquid ratio at atomizer; efficiency of con-
centration, which was weakly related to gas to liquid ratio at atomizer when it is more than 0.8, was proportional to inlet
heated air flow rate, inlet heated air lemperature, and reciprocal of dilute phosphoric acid flow rate; induced secondary air
did not facilitate concentration. Besides, coneentrated phosphoric acid that was up to 85% in mass fraction of H, PO, has
been obtained in experiment and it was also found that the temperature of relevant outlet gas should not be less than 110 C
So it is feasible to concentrate purified phosphoric acid to get comparatively high concentration by spray evaporation
key words phosphoric acid; spray evaporation; gas liquid ratio at atomizer
工业级磷酸的规格要求H3PO4的质量分数为提高传热推动力,且貝有传热传质面积大,物料温度
85%或75%,常见的二水物湿法僯酸(以P20。计,低,工艺流程简单等优点?,而且以往限制喷雾蒸
下同)的质量分数一般在28%~32%,而净化的湿发应用于磷酸浓缩的设备腐蚀问题已得到比较好的
法磷酸质量分数一般为20%左右。为达到使用改善4,该方法有望获得技术突破。笔者采用自主
要求和便于运输,对磷酸进行浓缩十分必要。目前,设计的316L材质的喷雾蒸发浓缩系统进行了净化
中国普遍采用外加热强制循环真空蒸发的方法来浓稀磷酸的浓缩实验研究,系统地考察影响磷酸浓缔
缩稀磷酸。此法采用低压蒸汽作热源,故传热推的各主要因素,探索适宜的操作条件,以期推动该技
动力受到很大限制,获得的磷酸极限质量分数为术在工业实践中的应用。
54%左右2。喷雾蒸发的方法可以在很大程度上
基金项目:国家科技支撑计划课题《高纯僯化工产品关键设备开发》资助项目(2007BAF58B02)。
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