燃煤电厂脱硫废水处理技术现状与发展_胡大龙.pdf

第 43 卷第 2 期2023年 2 月Vol.43 No.2Feb.，2023 工业水处理Industrial Water TreatmentDOI：10.19965/ki.iwt.2021-132443燃煤电厂脱硫废水处理技术现状与发展胡大龙 1，余耀宏 1，于胜利 2，尚卫军 3，李亚娟 1，李文东 2（1.西安西热水务环保有限公司，陕西西安 710054；2.锡林郭勒热电有限责任公司，内蒙古锡林郭勒 026000；3.北方联合电力有限责任公司，内蒙古呼和浩特 010020）摘要 在分析脱硫废水水质特点，以及调研排污许可证中脱硫废水去向和污染物排放执行标准的基础上，论述了脱硫废水达标处理、厂内回用和零排放的技术路线。排污许可证基本不允许脱硫废水外排，并对脱硫废水车间排放口水质进行了严格限定。约 80.0%电厂的污染物因子和限值按 火电厂石灰石-石膏湿法脱硫废水水质控制指标（DL/T 9972006）执行，部分电厂增加了氨氮污染物因子控制指标、下调了氟化物和 COD 限值。脱硫废水达标处理，一类污染物重金属主要采用化学沉淀法去除，二类污染物氟化物采用复合盐沉淀技术去除，曝气法和次氯酸钠氧化法相组合的工艺可同步去除脱硫废水中的 COD和氨氮。脱硫废水厂内回用方式包括湿除渣和干灰调湿，其中湿除渣系统应主要关注设备腐蚀问题，干灰调湿主要考虑气候以及对周围环境的二次污染问题。脱硫废水零排放采用结晶工艺时需考虑盐的处置以及需通过工艺优化避免产生二次污染物；目前旁路烟气蒸发工艺系统简单、无固废处置问题，是当前脱硫废水固化的主流工艺。关键词 脱硫废水；排污许可；一类污染物；二类污染物；零排放中图分类号 X703 文献标识码 A 文章编号 1005-829X（2023）02-0043-10Present situation and development of treatment technology for desulfurization wastewater in coal-fired power stationHU Dalong1，YU Yaohong1，YU Shengli2，SHANG Weijun3，LI Yajuan1，LI Wendong2（1.Xi an TPRI Water Management&Environment Protection Co.，Ltd.，Xi an 710054，China；2.Xilin Gol Thermal Power Co.，Ltd.，Xilin Gol 026000，China；3.North United Power Co.，Ltd.，Huhhot 010020，China）Abstract：On the basis of analyzing the water quality characteristics of desulfurization wastewater，as well as the direction of desulfurization wastewater and the discharge standards of pollutants in the sewage permit，the technical route of standard treatment，reuse and zero discharge of desulfurization wastewater were discussed.Almost all of the discharge permit basically did not allow the desulfurization wastewater discharge to external environment，and the quality of desulphurization wastewater at the discharge port of wastewater workshop was strictly limited.The pollutant factors and limits of about 80.0%of power plants were implemented according to Discharge Standard of Wastewater from Limestone-Gypsum Flue Gas Desulfurization System in Fossil Fuel Power Plant（DL/T 9972006）.Some power plants had added the control indexes of ammonia nitrogen and lowered the limits of fluoride and COD.In the treatment of desulfurization wastewater to reach the standard，heavy metals of class pollutants were mainly removed by chemical precipitation method，fluoride of class pollutants was mainly removed by compound salt precipitation technology，and the combined process of aeration and sodium hypochlorite oxidation could simultaneously remove COD and ammonia nitrogen in desulfurization wastewater.The reuse methods of desulphurization wastewater plant included wet slagging and dry ash humidification.The wet slagging system should mainly focus on equipment corrosion，and the dry ash mixed with wet should mainly consider the climate and the secondary pollution to the surrounding environment.The treatment of salt should be considered in the zero discharge of desulphurization wastewater by crystallization process，and the secondary pollutants should be avoided through process optimization.基金项目 华能集团科技项目（HNKJ19-H02）开放科学（资源服务）标识码（OSID）：专论与综述工业水处理 2023-02，43（2）44At present，the bypass flue gas evaporation process system was simple and had no solid waste disposal，which was the main curing process of desulphurization wastewater.Key words：desulfurization wastewater；discharge permit；first class pollutants；second class pollutants；zero discharge火电厂石灰石-石膏湿法脱硫工艺是我国燃煤电厂最主流的脱硫工艺，具有脱硫效率高且稳定、煤种适应性强、吸收剂来源广泛且价格低廉、副产物可资源化利用等优点。石灰石-石膏湿法脱硫工艺产生的脱硫废水水质复杂，悬浮物、重金属、致垢性离子和盐含量高，处理难度大。我国环境保护部已于2017 年 7 月前完成了火电行业排污许可证核发工作，要求火电厂持证排污并按证排污，脱硫废水处理能否满足排污许可证要求是火电厂废水达标治理的关键。因此，有必要根据脱硫废水原水水质和排污许可证对脱硫废水处理提出的具体要求，开发相应的脱硫废水处理技术，为火电厂脱硫废水治理工作提供技术支撑。1 脱硫废水水质与排放要求分析1.1脱硫废水水质燃煤性质、脱硫石灰石品质、工艺水水质和脱硫运行控制条件等均影响脱硫废水水质，因此各厂脱硫废水水质各异，且同一电厂不同时间阶段排出的脱硫废水水质也不同。脱硫废水处理车间或设施排放口出水水质一般执行 火电厂石灰石-石膏湿法脱硫废水水质控制指标（DL/T 9972006）。7家国内外火电厂脱硫废水水质见表 1。由表 1可知，因燃煤中重金属含量低，脱硫废水中重金属浓度也普遍较低；B 厂脱硫废水处理前重金属含量已全部满足 DL/T 9972006 要求，A 厂、E厂和 F 厂脱硫废水处理前也仅有 12 项重金属超标，处理后重金属均能满足 DL/T 9972006 要求。有研究表明，燃煤中的氟约 1.2%2.0%转移到脱硫废水中，60%80%转移到石膏中，2%5%通过烟气排入大气，剩余的氟转移至飞灰和炉渣中5。7家电厂中 A 厂、B 厂、E 厂和 G 厂脱硫废水氟离子浓度较高，且 A 厂和 B 厂脱硫废水氟离子质量浓度分别高达 308 mg/L 和 175 mg/L。脱硫废水中 COD 主要来自煤、工艺水中有机质，以及石灰石、脱硫反应生成表 1脱硫废水水质特性Table 1 Water quality characteristics of desulfurization wastewater项目总汞/（mgL-1）总镉/（mgL-1）总铬/（mgL-1）总砷/（mgL-1）总铅/（mgL-1）总镍/（mgL-1）总锌/（mgL-1）悬浮物/（mgL-1）COD/（mgL-1）氟化物/（mgL-1）硫化物/（mgL-1）pHCl-/（mgL-1）SO42-/（mgL-1）全硅/（mgL-1）1/2Ca2+/（mmolL-1）1/2Mg2+/（mmolL-1）总硬度/（mmolL-1）含盐量/（mgL-1）氨氮/（mgL-1）A厂0.0580.0030.0580.1040.0170.5101.7306 6805633080.0146.9415 1006 32093.964.50424.17488.6740 800270B厂0.0230.0800.3000.8210.735ND1 4401601756.625 0805 71015529.3086.70116.0019 0741 269C厂0.0100.0760.0370.003 00.070ND0.240117106227.125 1603 13565.550.78237.36288.1415 93761.75D厂 10.0100.1300.0030.071ND1.08ND0.0050.3800.8480.5041.0650.2751.413D厂 1ND0.025ND0.003ND0.055ND0.010.2810.7630.0470.444ND0.377E厂 20.0222.7790.4220.000 331242755.26.373 77034.0158.7192.7E厂 20.000 020.0040.050.001 1921036.013.07.28.07 00020 000F厂 30.0960.0940.050.006 20.7200.00811 05011.95.205 0092 02826.822.449.2G厂 40.010.800.050.100.301.000.500.800.51.52.07.00.51.025020 000700401004610