设计说明书：南化公司2007年7月29日建成投运了10万吨/年离子膜烧碱装置。原设计原料盐为固体海盐，除硝系统采用传统的氯化钡法工艺。近年来，随着固体海盐的来源日趋紧张和价格的不断上涨，南化公司氯碱生产局部尝试井矿盐和液体卤水盐的使用。液体卤水盐折合吨盐价格与固体盐价格有180~220元/吨的差价，在价格上有明显优势。10万吨/年离子膜烧碱装置最大限度改用液体卤水盐，可以降低企业生产成本、提高经济效益。9593
现有盐水精制装置中去除硫酸根的方法采用传统的氯化钡法。氯化钡属于一类毒物，受管制，生产产生的硫酸钡盐泥~2.7t/h，处理难度较大，影响环境。若采用卤水制碱，卤水中SO42-≤6.0g/l，而固盐中SO42-≤0.7g/l，需要去除更多的硫酸根，如仍然使用现有的氯化钡除硝工艺，除硝药剂费用高，增加装置运行成本，增加卤水与减少固盐节省的原盐成本几乎与增加卤水需要多消耗氯化钡的费用相当，原料路线改变对制碱成本降低不明显。本技术改造考虑采用先进、成熟、可靠的CIM膜法除硝技术，既可降低除硝成本，又能回收副产品硫酸钠，不需药剂氯化钡，实现无废液排放，减少环境污染。
该改造项目由上海三夫工程技术有限公司承接设计，我于2012年10月至今在该公司实习，在实习期间我参与了该设计任务的部分工作。为积极响应学校的校企联合做毕业设计的倡导，我与毕业导师商定，并经过公司的许可：选取该项目的部分内容作为毕业设计的课题，利用现有的条件作为我的毕业设计任务的条件。
采用卤水制碱，原装置需改造的内容为：
1）增加一套氯酸盐分解系统；
2）对现有卤水除氨系统进行改造；
3）增加一套膜法除硝系统；
4）增加一套淡盐水浓缩系统；
5）增加相应的公用工程管线及对部分设备进行改造。
本设计主要介绍了其中氯酸盐分解系统和膜法除硝系统的工艺流程的部分的设计。
关键词：膜法除硝；离子膜烧碱；氯酸盐分解；中性纳滤膜；元明粉
100000 tons/year membrane ionic membrane caustic soda, sodium sulfate removal process design
Design instruction：
Nahua company built on July 29, 2007 put into operation 100000 tons/year of ionic membrane caustic soda unit. Original design salt raw material for solid salt, sodium sulfate removal system adopts the traditional process of barium chloride method.
In recent years, with solid sea salt source and rising prices, Nahua company were try to use brine well mineral salt and liquid salt. Liquid solid salt and salt is equivalent to tons of salt brine prices 180 ~ 220 yuan/ton price difference, has obvious advantages on price. 100000 tons/year of ionic membrane caustic soda unit to switch to liquid brine of salt to the greatest extent, can reduce production cost and improve the economic benefit.
In the traditional, the barium chloride method is to remove sodium sulfate. Barium chloride belong to the type of poison, controlled, the production of barium sulfate salt mud ~ 2.7 t/h, the processing difficulty is bigger, affect the environment. If using alkali brine system, SO42-6.0 g/l or less in the brine, and the SO42 - in solid salt acuities were 0.7 g/l, need to remove more sulfuric acid root, if you still use the existing chlorinated barium nitrate process, in addition to the high cost of nitrate reagents, increase plant operation cost, increase and decrease of solid salt brine to save our costs and increase almost need more consumption of barium chloride brine cost, raw material route change to alkali production cost reduction is not obvious. This technical transformation considering the use of advanced, mature, reliable CIM membrane in addition to nitrate technology, either in addition to the cost of nitrate reduction, and recycling byproduct sodium sulfate, without reagent barium chloride, no waste discharge, reduce the pollution of the environment. 年产10万吨离子膜烧碱膜法除硝工艺设计:http://www.751com.cn/huaxue/lunwen_8379.html