文章摘要
罗兴国,魏昶,李兴彬,李永勇,郑三强,李旻廷.真空制盐中碳酸根离子的转化与阻垢防垢[J].精细化工,2020,37(12):
真空制盐中碳酸根离子的转化与阻垢防垢
Conversion of carbonate and scale inhibition and prevention in vacuum salt production
投稿时间:2020-05-19  修订日期:2020-06-27
DOI:
中文关键词: 真空制盐  阻垢防垢  碳酸根  碳酸氢根  腐蚀
英文关键词: vacuum salt making  scaling prevention and scaling removal  CO32–  HCO3–  corrosion
基金项目:云南省科技计划科技入滇专项(20181B030); 昆明市科技计划重点项目(项目编号:2018-1-H-17215)
作者单位E-mail
罗兴国 昆明理工大学 1475697675@qq.com 
魏昶 昆明理工大学冶金与能源工程学院  
李兴彬 昆明理工大学冶金与能源工程学院 lixingbin2011@126.com 
李永勇 昆明理工大学冶金与能源工程学院  
郑三强 昆明理工大学冶金与能源工程学院  
李旻廷 昆明理工大学冶金与能源工程学院  
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中文摘要:
      针对盐硝联产工艺中成垢阴离子CO32–浓缩富集导致蒸发系统结垢问题,研究采用盐酸多段调节卤水pH值,使CO32–转化为HCO3–,有效地缓解了系统结垢延长生产周期。通过热力学计算、XRD、SEM-EDS等技术探究了加酸过程中CO32–与HCO3–的转化行为,得出以下结论。盐硝蒸发系统垢泥主要由CaCO3垢和Mg(OH)2垢组成,但结垢机理有所区别。盐系统结垢的诱因是逐效富集的Ca2 随着温度的升高而形成低溶解度的CaCO3达到过饱和状态沉积析出形成垢层,硝系统结垢的主要原因是卤水中CO32–和OH–的成倍富集;理论计算和实验结果指出,调节母液的pH至9.0 ~ 9.5,可使局部的CO32–转化为HCO3–;垢层的浸出实验表明,调节卤水pH至9.08,Mg2 能有效的溶解浸出,而仅有少部分的Ca2 溶解浸出。SEM-EDS结果表明,未被浸出的钙形成致密的垢层可抑制换热管表面结垢,实现了在防止系统腐蚀的同时,可使CO32–转化为HCO3–,有效地缓解了系统结垢。
英文摘要:
      In view of the scaling anion CO32– concentration and enrichment in the co-production process of salt-nitrate, which leads to scaling problems in the evaporation system, the study used multi-stage hydrochloric acid to adjust the brine pH to convert CO32– to HCO3–, alleviating system scaling and extending the production cycle effectively. The results of thermodynamic calculation, XRD, SEM-EDS and other technologies show that the conversion behavior of CO32– and HCO3– during the acid addition process was explored, and the following conclusions were drawn. The scale of the salt and nitrate evaporation system is mainly composed of CaCO3 scale and Mg(OH)2 scale, thought the scaling mechanism is different. The cause of scaling in the salt system is that the gradually enriched Ca2 forms low-solubility CaCO3 as the temperature rises, and the supersaturated state deposits and precipitates to form a scale layer. The theoretical calculation and experimental results indicate that adjusting the pH of the mother liquor of the nitrate system to 9.0 ~ 9.5 can convert local CO32– to HCO3–. The leaching experiment of scale layer shows that adjusting the pH of brine to 9.08, the Mg2 can be dissolved and leached effectively, but only a small part of Ca2 were dissolved and leached. The SEM-EDS results show that the dense scale layer formed by the un-leached calcium can inhibit scale formation on the surface of the heat exchanger, realizing the conversion of CO32– to HCO3– while preventing system corrosion, and alleviate system scale inhibition and prevention effectively.
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