磷酸萃取过程的挖潜与节能、减排(待续)

Revamp,Energy Saving and Emission Reduction for Phosphoric Acid Extraction(to be continued)

理论研究与实践经验表明:磷酸萃取过程磷石膏结晶的形状、大小与反应温度和时间无关,只与硫酸能量浓度有关;因此,缩短反应时间、提高反应温度是提高装置能力,进行挖潜改造的关键。过滤既是固液分离又是冷却单元操作,由于过滤系统的冷凝水可回收利用,因而调整过滤工艺条件,提高过滤速度和装置生产能力,对降低磷酸萃取过程电耗和萃取尾气的逸出量,达到污水零排放等节能减排措施方面起着至关重要的作用。

Both theoretical study and actual experience indicate that,the shape and size of phosphogypsum crystal during phosphoric acid extraction have nothing to do with the reaction temperature or time,it is only related to the energy density of sulfuric acid.Therefore,reduction of reaction time and increase of reaction temperature are the key for revamp of the plant so as to increase its capacity.Filtration is a unit operation both for separation of solid from liquid and cooling.Since the condensate water from the filtration system can be recycled,it is very important to adjust the process conditions for filtration,increase the filtration rate and the plant production capacity,so as to meet the energy saving and emission reduction policies for reduction of electricity consumption and emission of extraction tail gas,as well as zero discharge of waste water during phosphoric acid extraction.