工业废盐制备纯碱工艺的开发

发布时间：2018-06-08 08:09

  本文选题：纯碱 + 废盐　； 参考：《北京化工大学》2016年硕士论文

【摘要】：本研究以工业废弃氯化钠与碳酸氢铵作为原料,利用水溶液体系中发生的复分解反应原理,制备了纯碱并联产氯化铵,其中生产纯碱的生产单元为本工艺的第一单元,回收来自第一单元母液中的氯化铵为第二单元。采用正交试验法,通过实验系统研究了第一单元中反应温度、反应时间及反应物料比对单次反应生成的中间产物碳酸氢钠收率的影响,以获得较优的工艺条件；选择了盐析剂并确定其用量以进一步回收第一单元母液中碳酸氢钠,盐析剂经处理后循环利用；采用浓缩结晶方法,研究了第二单元回收氯化铵的工艺条件；在此基础上,完成了年处理7.3万吨工业废盐制备纯碱联产氯化铵的工艺物料衡算,并进行了关键设备的选型。首先,根据水盐体系四元交互相图确定了第一单元的工艺条件范围,研究了反应温度和时间对中间产物碳酸氢钠收率的影响,实验发现适当提高反应温度并延长反应时间有助于提高碳酸氢钠收率,同时适当调整反应物料比也可提高碳酸氢钠收率；进一步的正交试验结果表明,在优化的工艺条件下,即反应温度为35℃,废盐与碳酸氢铵的物质量比为1.05,反应时间为120min时,第一单元单次中间产物碳酸氢钠收率最高,达到75%,经400℃煅烧后得到纯碱纯度超过98%,符合国家标准。为了提高碳酸氢钠的收率,本研究利用反溶剂原理,选用三种有机盐析剂对母液进行处理。实验结果显示,选用盐析剂C并且用量为废盐物质量的1.5倍时,可从母液中再度析出的碳酸氢钠量达到单次反应产量10%以上,第一单元单循环可制备碳酸钠收率超过88%。在第二单元,采用中和反应原理,利用两种酸对来自第一单元的盐析后的澄清母液进行处理后回收氯化铵,其中浓盐酸处理所得氯化铵收率最高为86.42%,副产物氮含量符合国家标准。利用工艺流程模拟软件Aspen对年处理量7.3万吨废氯化钠生产纯碱并联产氯化铵工艺流程进行了物料衡算,完成了PFD图与PID图,并对关键设备进行了初步计算和选型。
[Abstract]:In this study, the industrial waste sodium chloride and ammonium bicarbonate were used as raw materials, and the principle of double decomposition reaction in aqueous solution was used to prepare soda and co-produce ammonium chloride, in which the unit of producing soda was the first unit of this process. The recovery of ammonium chloride from the first unit mother liquor is the second unit. The effects of reaction temperature, reaction time and reactant ratio on the yield of sodium bicarbonate in the first unit were studied by orthogonal test. The sodium bicarbonate from the first unit mother liquor was further recovered by selecting salting-out agent and its dosage was determined. The salting-out agent was reused after treatment. The technological conditions for recovering ammonium chloride in the second unit were studied by means of concentrated crystallization. The material balance of 73000 tons of industrial waste salt per year for the production of ammonium chloride from soda is completed, and the selection of key equipment is carried out. Firstly, according to the quaternary phase diagram of water-salt system, the technological conditions of the first unit were determined, and the effects of reaction temperature and time on the yield of sodium bicarbonate, the intermediate product, were studied. It is found that increasing the reaction temperature and prolonging the reaction time can improve the yield of sodium bicarbonate and adjust the ratio of reactant to material to increase the yield of sodium bicarbonate. When the reaction temperature is 35 鈩，

本文编号：1995273