玉米深加工行业是耗水大户,其中循环冷却系统补充水用量占整个生产用水 量的近30%,如果能够将企业废水处理到循环冷却系统补充水标准并回用,可以 降低新鲜水用量,减少污染物的排放,具有环境效益和经济效益本文是/十一 五0国家水专项/辽河源头区水质改善与生态修复技术及示范研究0课题的部分 内容,依托中粮生化能源(公主岭)有限公司再生水回用项目开展研究 本报告主要针对企业循环冷却系统的现状进行调查分析;采用旋转挂片腐蚀 试验与电子扫描电镜相结合,研究影响较大的腐蚀因子对不锈钢及碳钢材质的腐 蚀情况,探索水质与系统腐蚀程度的关联性;针对企业废水深度处理小试装置出 水开展腐蚀试验,与企业目前补充水对系统的腐蚀影响进行比较分析,讨论该类 废水回用于循环冷却系统的可行性 通过现场调查和监测分析,企业各循环冷却系统内水质波动较大,其中糊精 车间氯离子瞬时浓度高达114Omg/L,存在腐蚀隐患 氨氮!有机物!氯离子!硫酸根对碳钢和不锈钢的影响均较大,且腐蚀速率 随各因子浓度的增加而增大对于不锈钢材质,氨氮浓度大于ZOm留L!CODcr 浓度大于50m留L!氯离子浓度大于500mg/L!硫酸根浓度大于200m岁L时不能 满足5工业循环冷却水处理设计规范6(GB5O050一2007)中规定的要求,且氯离 子及硫酸根的腐蚀方式类似;对于碳钢材质,氨氮浓度大于sm岁L!BODS浓度 大于ZOmg几!CODc;浓度大于25m留L时不能满足要求,而氯离子和硫酸根对碳 钢的影响较不锈钢严重,在50mg几和30m留L时就己超过标准约2倍 考察企业目前补充水对系统各材质的腐蚀影响,试验结果显示海军铜材质较 不锈钢耐受性差,腐蚀速率为0.O06mm/a,不锈钢各型号腐蚀速率均低于 0.005m耐a各材质对该地区地下水的耐受性排序为不锈钢316>不锈钢304>不 锈钢321>海军铜; 将深度处理小试装置出水与目前企业补水进行10%一50%的配比,并改变缓 蚀阻垢剂的投加浓度,在不同比例不同药剂量情况下与企业目前补充水对系统的 腐蚀状况进行比较分析,同时结合扫描电子显微镜观察试验挂片的腐蚀程度,得 出BAF及MBR出水直接作为循环冷却系统补充水不具有可行性,其中氯离子 是引起腐蚀的最主要因子中国环境科学研究院硕士学位报告 反渗透工艺能够有效降低氯离子浓度至小于0.5pg/L,且出水水质各指标均 优于地下水,采用反渗透出水作为循环冷却系统补充水,可以减少新鲜水的用量, 节约药剂费用与排污费用,目前企业循环冷却系统运行成本为2.38元/吨,在不 考虑反渗透装置投资折旧成本的前提下,采用反渗透工艺作为再生水回用工艺的 成本为2.05元/吨 关键词:玉米深加工;再生水回用;循环冷却系统;腐蚀;中国环境科学研究院硕士学位报告 Abstraet CornProeessingindustry15enormouslywater-eonsumingwithwaterusedforthe reeireulatingeoolingsystemreaehingnearly30%ofthetotalwatereonsumPtion.IftheProdueed wastewatereanbetreatedtosatisfytheeoolingsystemsuPPlementwaterstandardsandreused,it willnotonlysavetheamountoffreshwaterneeded,butalsoredueeemissionsofPollutants, whiehwouldhavebothenvironmentalandeeonomiealbenefits.Thisstudy15Partofthe01Ith five一yearPlanofnationalwaterProjeet/waterqualityimProvement,eeologiealrestoration teehniquesanddemonstrationresearchThisstudy15alsobasedontheregeneratedwaterreuse ProjeetofCOFCObioehemiealenergy(Gongzhuling)Co.,LTD,. Basedontheinvestigationandanalysisaboutstatusofreeireulatingeoolingsystem,thestudy eombinestheteehnologiesofrotatinghangingPieeeswithseanningeleetronmieroseoPe,and investigatestheinflueneeofsignifieanteorrosionfaetorsontheeo加sionofearbonsteeland stainlesssteelhangingPieees.ExPlorationontherelevanceofwaterqualityandeorrosiondegrees 15Performed.Regeneratedwatereorrosiontest15earriedoutonPilot一sealedeePtreatment faeilitiesandtheresultsareanalyzedeomParedtoinfiueneeineurrentsystemsduetothe eorrosionofsuPPlementwater.DiseussingonthefeasibilityoftheusingsuehsuPPlementing waterinthereeireulatingeoolingsystems.Aeeordingtothefieldinvestigationandmonitoring analysis,thewaterqualityinthereeireulatingeoolingsystemfluetuatedobviously.The reeireulatingeoolingsystemhasriskofbeingcorrodederodedbyCI一beeausetheinstantaneous eoneentrationofCI一eanreach1l40mg/LindextrinProduetionworkshoP. TheimPactsofammonianitrogen,organiematter,chlorideion,sulfateiononearbonsteel andstainlesssteelareobservedtobesignifieantandtheeorrosionrateinereaseswiththe eoneentration.rorstainlesssteel,whentheeoneentrationsofNH3闪,eoDer,el一and5042一are Ia吧erthanZomg/L,50mg/L,50omg/LandZO0mg几respectively,therequirementsin5Codefor designofindustrialreeirculatingcoolingwatertreatment6(GB50050一2007)couldnotbesatisfied. It15alsofoundthattheeorrosiontyPesofehorideandsulfateionsaresimilar.Forearbonsteel, whentheconeentrationsofNH3一,BODSandCODe;aregreaterthansmg/L,20mg/Land 25mg/LresPeetively,therequirementseouldnotbesatisfied,whileatthesametimetheimPaetof ehlorideionsandsulfateionsonearbonsteel15moresignifieantcomParedtothatonthestainless 111中国环境科学研究院硕士学位报告 steel.Withtheeoneentrationlevelsofehlorideionsandsulfateionsareat50mg/Land30mg/L, theeorrosionrate15observedtoexeeedthestandardvaluesbyafactoroftwotimes. Studiesontheeorrosionofmaterialsusedinthesystemseaused勿suPPlementwaterreveals thatthenavyeoPPer,withtheeorrosionrate0.006mm/a.haslesseorrosiontoleraneethanall kindsofstainlesssteelofwhiehthetoleraneesaremeasuredtobelessthan0.005mnl/a.The tolerabilityofeachmaterialagainsttheIoealgroundwatereanbeidentifiedtobestainlesssteel 316>stainlesssteel>304stainlesssteel321>navybrass. ThetreatedwaterfromdeePtreatmentPilotsealefacilitiesaremixedwitheurrentlyused suPPlementalwaterwithamixingratioof100/0一50%,andthedosageofeorrosioninhibitorare variedaswell.ThemjxtureswithdifferentmixingratiosanddosagesareeomParedwiththe suPPlementalwaterthat15eurrentlyinusebasedontheeorrosionofthesystemsandthe observationontheeormsionoftestedhangingPlateswithSEM15involvedaswell.Theresults showthatit15notfeasibleforthewaterfromBAFandMBRtobeusedaswatersuPPlementof eireulationeoolingsystemdireetly.Theehlorideion15themainfaetoreausingeorrosion,50it15 neeessarytofurtherredueeehlorideioneoneentrationbeforereeyele. Theehlorideioneoneentrationwillberedueedbyreverseosmosisteehnologytolessthan0.5 p幼副,andthequantitiesoffreshwaterandeorrosioninhibitors,aswellastheexPensesofwaste waterwillberedueedifthewaterfromreverseosmosiseanbeusedforthewatersuPPlementof reeireulatingeoolingsystemdireetly.TheoPerationeostofeyelieeoolingsysteminCOFCO bioehemiealenergy(GongZhuling)Co.,LTD,.152.38yuan众.Theoperationeostofreverseosmosis teehnologyasdeePtreatmentteehnologyoftheeyclieeoolingsystem152.05yuan/tifthe oPerationeostofinvestmentdePreeiation15nottakenintoaeeount. Keywords:ComdeePProeessing;regeneratedwaterreused;reeirculatingeoolingsystem; CO汀OS10n; lV中国环境科学研究院硕士学位报告 目录 摘要.,........................-.................................,.........,.........................................I Abstract.,..........................................................~.........................-.........................111 目录.....,.......................,二,......,.......................................,...............................V 第一章绪论.....................一~,................................-................,.................................1 1.1我国玉米深加工行业概况及排放废水特征..................!.........-.....................l 1.1.1玉米生产布局特征.................................................#,1 1.1.2玉米深加工企业特征,.........................................1 1.1.3玉米深加工品种结构特征....,....................................................................2 1.1.4玉米深加工行业需求变化.,....#,2 1.1.5玉米深加工行业排放废水特征.......................................................................3 1.2再生水回用的意义与途径..................#.,#5 1.2.1我国水资源状况.....................,..............,5 1.2.2吉林省水资源状况......................................,.#6 1.0再生水回用的意义.........................................#..#8 1.2.4再生水回用的途径........................................#9 1.3冷却水系统概述.........................................................................................................9 1.3.1直流冷却系统二~...........,.......................................................#.....9 1.3.2循环冷却系统...............................................,....................................,二10 1.4再生水回用于循环冷却系统应用现状................................,............................11 1.4.1国外再生水回用于循环冷却系统的应用现状............................................n 1.4.2国内再生水回用于循环冷却系