煤化工浓盐水蒸发结晶分离工业盐的实验研究

发布时间：2018-03-24 23:06

本文选题：煤化工浓盐水　切入点：钝化-络合　出处：《哈尔滨工业大学》2017年硕士论文

【摘要】：我国能源结构的现状促进传统煤化工行业向现代煤化工行业转型,以煤制油、煤制天然气等煤炭清洁利用措施来弥补能源结构缺陷。但现代煤化工行业的高耗水、高污染现状,煤炭资源、水资源的逆向分布特征以及国家环保部严格提出的“零排放”要求制约着煤化工行业的发展。煤化工浓盐水作为零排放的瓶颈问题,处理难度大、成本高。以传统蒸发结晶方式处理浓盐水,产生结晶杂盐的处理成本为3000元/t,其处理费用可达到煤化工企业废水处理总费用的60%。为进一步实现零排放要求,促进煤化工行业稳健发展,本课题进行煤化工浓盐水蒸发结晶分离工业盐的实验研究,并进行现场分盐试验系统的调试与运行,针对煤化工行业现有的结晶杂盐,提出资源化利用的处理方案并进行实验探究,最后分别对结晶杂盐资源化利用工艺及蒸发结晶分盐工艺作技术经济成本分析。论文根据浓盐水水质条件进行钝化-络合预处理实验,通过投加药剂Ca O、MgO、PAC、PAM、Na2CO3去除浓盐水中的硬度、碱度、活性硅及重金属离子,经实验确定药剂最佳投加量分别为80mg/L、2500mg/L、120mg/L、2mg/L、70mg/L,对Ca2+、Mg2+、碱度、Mn2+、Al3+、总Fe及总Si的去除率分别76.07%、88.31%、44.53%、50.00%、78.64%、25.73%、49.71%,各离子去除率之和为412.99%。浓盐水经钝化-络合预处理,可减少对现场分盐试验系统碟管式纳滤(DTNF)单元膜污染及蒸发结晶单元腐蚀结垢问题。针对钝化-络合工艺对浓盐水中重金属离子去除效果不佳的问题,选择煤化工浓盐水特征重金属离子Cu2+、总As及Ni2+,提高其在浓盐水中的浓度进行配水实验,探究浓盐水TDS、TOC及pH变化对重金属离子去除效果的影响。实验确定最佳絮凝剂为FeSO4,强化最佳投量为90mg/L。在浓盐水TDS 54000mg/L、TOC180mg/L,pH 6-10条件下,Cu2+、Ni2+及总As去除的最佳pH分别为9.80、9.80、7.85,去除率分别为73.00%、71.25%、46.67%。根据确定的最佳pH,在实验过程引入Na2CO3进一步提高重金属去除率,Na2CO3投量确定为120mg/L。实验最后引入Ca2+,分析金属离子水合作用对重金属离子去除的影响。根据预处理实验确定的投药条件,依托煤化工浓盐水TMC热膜耦合分离技术,进行现场试验系统的调试与运行,其工艺单元包括钝化-络合及树脂软化预处理单元、DTNF单元,多相共结晶催化氧化(HCOS)单元及蒸发结晶单元,通过DTNF单元将Cl-、SO42-分离并形成产水与浓水两类水质,利用HCOS技术单元对有机物进一步去除,TOC去除率稳定在55.22%-61.60%,最后经蒸发结晶单元分别结晶Na Cl、Na2SO4,其中Na Cl结晶盐满足精制工业盐工业湿盐一级指标,Na2SO4结晶盐满足工业盐II类二级指标。煤化工浓盐水经TMC热膜耦合处理,总盐理论回收率可达74.67%,其中NaCl回收率为86.42%、占总盐49.16%,Na2SO4回收率为91.59%、占总盐的25.51%。产水与浓水进行蒸发结晶的母液理论外排比分别取1%、5%,连续外排母液0.0156m3/h,进行结晶、生化或干化处理。论文对结晶杂盐提出资源化利用的处理方案,即向结晶杂盐投加浓H2SO4制备工业级NaHSO4,根据实验确定适宜反应条件分别为H2SO4浓度90%-98%,投加方式1:2.5,反应温度130℃,反应时间30min,蒸馏水1:1投加,采用饱和Na HSO4洗涤,所制备NaHSO4满足工业I类一等品标准。根据该处理方案设计工艺流程,进行经济成本分析,结晶杂盐处理费用为36.49元/t,相比其作为危废处理,技术与经济性优势明显。煤化工浓盐水蒸发结晶分盐效果良好,浓盐水资源化利用率高,与常规蒸发结晶制备结晶杂盐及自然蒸发工艺相比,浓盐水处理费用分别为50.32元/t、234.34元/t、204.35元/t,固(危)废处理费用占比分别为16.67%、84.39%、96.78%,蒸发结晶分盐工艺处理费用低,产生固(危)废量少,资源化利用率高,具有明显技术与经济优势。本研究以煤化工浓盐水蒸发结晶分盐及资源化利用为核心,进行浓盐水的预处理实验及现场分盐试验系统运行与调试,提出结晶杂盐资源化利用方案,并对结晶杂盐资源化利用及煤化工浓盐水蒸发结晶分盐工艺作经济性分析。结晶杂盐资源化利用处理成本低,可从根本上解决结晶杂盐产量大、处理成本高、易二次污染的问题。煤化工浓盐水TMC热膜耦合工业盐分离技术总盐回收率高、结晶盐纯度高、母液排量小、产生危废少、清洁水回收率高,具有良好的工程应用前景。
[Abstract]:Status quo of China's energy structure and promote the transformation of traditional coal chemical industry to a modern coal chemical industry, the coal oil, coal and natural gas and other clean coal utilization measures to make up for the defects of the energy structure. But the high water consumption of modern coal chemical industry, high pollution, coal resources, water resources distribution and reverse state environmental protection the Ministry strictly proposed "zero emissions" requirement restricts the coal chemical industry. The development of coal chemical industry as the bottleneck problem of brine zero emissions, processing difficulty, high cost. Concentrated saline processing in the traditional way of evaporation and crystallization of crystal salt, produce treatment cost is 3000 yuan /t, the treatment cost can be achieved in coal chemical industry the total cost of the wastewater treatment 60%. for the further implementation of zero emission requirements, and promote the healthy development of coal chemical industry, this paper studied the coal chemical separation of industrial salt brine evaporation and crystallization, and in the field Commissioning and operation of salt test system, the coal chemical industry the existing crystal salt, put forward a plan to deal with resource utilization and experimental research, finally the crystal salt resource utilization technology and process technology of evaporation and crystallization of salt. The paper analyzed the cost according to the water quality conditions of brine experiments passivated complexation pretreatment by adding medicament to Ca O, MgO, PAC, PAM, Na2CO3 removal of brine in alkalinity, hardness, silicon and heavy metal ion activity, through experiments to determine the optimum dosage of drugs were 80mg/L, 2500mg/L, 120mg/L, 2mg/L, 70mg/L, Ca2+, Mg2+, Mn2+, Al3+, total alkalinity. Fe and the total removal rate of Si were 76.07%, 88.31%, 44.53%, 50%, 78.64%, 25.73%, 49.71%, the removal rate of 412.99%. ion and brine after passivation complexation pretreatment can reduce the salt field test system of disc tube nanofiltration (DTNF) membrane fouling and unit The evaporation crystallization unit corrosion and scaling problem. Aiming at the problem of poor removal of heavy metal ions in the brine passivation complexation process, selection of coal chemical brine characteristics of heavy metal ion Cu2+, total As and Ni2+, increasing its concentration in the brine in the water experiment, inquiry concentrated salt water TDS, the removal effect of heavy metals ion TOC and pH changes. The optimal flocculant was FeSO4, the best strengthening dosage of 90mg/L. in brine and TDS 54000mg/L, TOC180mg/L, pH 6-10, Cu2+, pH Ni2+ and the best As removal was 9.80,9.80,7.85, the removal rates were 73%, 71.25%, 46.67%. pH is determined according to the best, the introduction of Na2CO3 in the experimental process to further improve the removal rate of heavy metal, the dosage of Na2CO3 was 120mg/L. into Ca2+ at the end of the experiment, effect of metal ion hydration on the removal of heavy metal ions. According to the pretreatment experiment The dosing condition, relying on coal chemical brine TMC thermal coupling membrane separation technology, debugging and running test system, the process unit includes a passivation and chelate resin softening pretreatment unit, DTNF unit, multi phase catalytic oxidation of CO crystallization (HCOS) unit and evaporation crystallization unit, the DTNF unit Cl- SO42-, separation and the formation of water and concentrated water two water quality, further removal of organic matter by using the technology of HCOS unit, the removal rate of TOC was stable in 55.22%-61.60%, the evaporation crystallization unit respectively Cl Na2SO4, Na crystal, Na Cl crystal salt refining industrial salt industry meet the wet salt level index, Na2SO4 crystal salt meet industrial salt II class of two grade indicators. The coal chemical brine by TMC thermal coupling membrane treatment, the total salt theoretical recovery rate reaches 74.67%, the recovery rate of NaCl was 86.42%, accounting for 49.16% of total salt, Na2SO4 recovery rate was 91.59%, accounting for 25.51%. of total salt and water production The theory of mother liquor evaporation concentrated water and parallelism were taken 1%, 5%, continuous discharge liquor 0.0156m3/h, crystallization, biochemical or dry processing. The crystal salt solution is presented to resource utilization, namely to crystal salt equipment industrial grade NaHSO4 and concentrated H2SO4 system, according to the experiment to determine the appropriate the reaction conditions were H2SO4 concentration 90%-98%, 1:2.5 dosage, reaction temperature 130 C, reaction time 30min, 1:1 dosage of distilled water, washing with saturated Na HSO4, prepared by NaHSO4 I meet the industrial grade a standard. According to the scheme design process, economic cost analysis, the cost for handling crystal salt 36.49 yuan /t, compared to the hazardous waste treatment, technical and economic advantages. Coal chemical Brine Evaporation and crystallization of salt well, brine resource utilization rate is high, and the conventional evaporation crystallization preparation of crystal salt and natural evaporation. Art than brine treatment costs were 50.32 yuan /t, 234.34 yuan /t, 204.35 yuan /t, solid waste treatment costs (risk) accounted for 16.67%, 84.39%, 96.78%, evaporation and crystallization of salt treatment process of low cost, produce less waste solid (hazardous), resource utilization rate is high, has the obvious technical and economic advantages. The research on the coal chemical Brine Evaporation and crystallization of salt and resource utilization as the core of the brine pretreatment experiment and field operation and debugging experiment of salt system, put forward the crystallization solutions using mixed salt resources, and the crystal salt resource utilization and coal chemical brine evaporation crystallization salt technology economic analysis. Crystal salt resource utilization of low processing cost, can fundamentally solve the crystal salt yield, high processing cost, easy two pollution problems. The coal chemical brine TMC thermal coupling membrane separation technique of industrial salt salt high recovery rate, crystallization The purity of salt is high, the discharge of mother liquid is small, the waste is less, the recovery rate of clean water is high, and it has a good prospect of engineering application.

【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X784;TQ028.6

【参考文献】