中和混凝、氧化法在油田压裂废水处理中的应用研究

西安建筑科技大学硕士学位论文中和混凝、氧化法在油田压裂废水处理中的应用研究专业：建筑与土木工程硕士生：万瑞瑞指导教师：高湘副教授摘要近年来，我国的石油化工行业得到了迅猛的发展，它取得可喜发展成绩的同时也带来了严重的环境污染问题。由于返排至地面的压裂废水中含有胍胶、交联剂、稳定剂、破胶剂等多种添加剂，使其具有高CODcr、高色度、高粘度、高稳定性、难降解等特点，若不经过处理而直接外排，将会对周围环境，尤其是对农作物、地表水系、大气环境造成严重污染。针对上述问题，本课题首先分析了实验室油田压裂废水水样的水质特点。然后通过大量的文献阅读和实验研究确定了“中和─混凝─NaClO氧化─微电解”组合工艺来处理油田压裂废水。最后，将此工艺应用到长庆公司的压裂废水处理中，并优化了各分工艺的操作条件，同时检验了该组合工艺的处理效果。实验结果表明：中和实验中，Ca(OH)2的最佳投加量为8g/L；混凝实验中，当废水pH=7、温度为30℃、快速搅拌速度为300转/min，搅拌时间为2min，慢速搅拌速度为80转/min、搅拌速度为10min、PAC0.6g/L、PAM0.003g/L时，中和混凝效果达到最佳，对浊度、石油类的去除率比较高，分别为89.2%、83.6%，对CODcr的去除率较低，只有37.1%。同时也表明了，Ca(OH)2、PAC、PAM的最佳投加量随石油压裂废水水质的不同而有所不同；次氯酸钠氧化实验中，当pH=3，NaClO的投加量为0.8g/L，氧化时间为30min时，对浊度和CODcr的去除率最高，分别为56.7%和47.7%；在微电解实验中，当pH=3，压裂废水经自制微电解反应器反应30min后，浊度的去除率为45.1%，CODcr的去除率达到60.8%；与中和混凝、次氯酸钠氧化相比，微电解对压裂废水的CODcr去除效果最好；压裂废水经整个组合工艺处理后，浊度和石油类的去除率分别达到97.6%和98.0%，CODcr也从4937mg/L降低至637mg/L，去除率达到87.1%。课题研究表明：“中和─混凝─NaClO氧化─微电解”组合工艺在处理油田压裂废水方面具有较好的效果，各项水质指标大大降低，废水水质得到了明显净化，该实验具有一定的可行性。关键词：油田压裂废水；中和；混凝；次氯酸钠氧化；微电解西安建筑科技大学硕士学位论文ApplicationStudyonNeutralization-CoagulationandNaClOOxidationforTreatmentofOilfieldFracturingWastewaterSpecialty：ArchitectureandCivilEngineeringName：RuiruiWanInstructor：A.Professor.XiangGaoABSTRACTInlastseveralyears,petrochemicalindustryofourcountrywasdevelopedalot,however,seriousenvironmentalpollutioncomeswithgratifyingresults.FracturingwastewaterwhichwillflowbacktothegroundishighCODcr,chroma,viscosity,stabilityandrefractoryforaddinginlotsofadditive.Thesurroundingenvironment,especiallycrops,surfacewaterandatmosphericenvironmentwillbepollutedheavilyiffracturingwastewatergoeswithouttreatment.Thecharacteristicsoftheoilfieldfracturingwastewaterisanalyzedfirstlyinthethesis,thenthecombinationprocess“Neutralization—Coagulation—NaClOoxidation—Micro-electrolysis”comesouttotreatmentthewastewaterafterlotsofliteraturereadingandexperiments.Finally,thisprocessisappliedtotreatmentfracturingwastewaterofChangqing,andtheoperatingconditionsofeachsub-processareoptimized.Theresultshowsthecombinationprocesshasagoodperformance.Thefollowedconclusionsissupportedbyexperiments:thebesteffectwillbegottenbyneutralizationcoagulationexperimentwhendosing8g/LofCa(OH)2,0.6g/LPACand3mg/LPAM,theremovalratesofturbidityandoilsareveryhigh,89.2%and83.6%,respectively,butlowerremovalrateofCODcrinthesituation,only37.1%.ItalsoshowsthatthedosagesofCa(OH)2,PACandPAMaredifferentinthedifferentfracturingwastewater;Thehighestremovalratesofturbidityandoils,56.7%and47.7%,respectively,willbegottenbyNaClOoxidationexperimentswhenpH=3,dosageofNaClOis0.8g/Landoxidationtimelasts30minutes;Theremovalrateofturbiditywillget45.1%andCODcrwillget60.8%afterfracturingwastewaterishandledbyself-mademicro-electrolysisreactiondevicefor30minuteswhenpH=3inmicro-electrolysisexperiment;TheremovalrateofCODcrinmicro-electrolysisisthehigestcomparedtoNeutralization-coagulationandNaClOoxidation;Afterfracturing西安建筑科技大学硕士学位论文wastewaterishandledbythewholecombinationprocess,theremovalrates97.6%and98.0%forturbidityandoilswillbereached,CODcrwillbereducedfrom4937mg/Lto637mg/L,theremovalrateis87.1%.Theresearchshowedthatthecombinationprocess“Neutralization—Coagulation—NaClOoxidation—Micro-electrolysis”hasplayedapositiveandeffectiveroleinthetreatmentofoilfieldfracturingwastewater,wastewaterqualityhasbeenimprovedsignificantlyandtheexperimentisverifiedtobefeasible.Keywords:oilfieldfracturingwastewater,neutralization,coagulation,NaClOoxidation,micro-electrolysis西安建筑科技大学硕士学位论文I目录1绪论........................................................................................................................11.1油田压裂液概述...........................................................................................11.1.1油田压裂液的定义..............................................................................11.1.2油田压裂液的种类及其特点和应用条件...........................................11.1.3油田压裂液的主要成分......................................................................21.1.4压裂废水的特点及其危害..................................................................31.2常用油田压裂废水处理方法........................................................................41.2.1物理法.................................................................................................41.2.2化学法.................................................................................................41.2.3生物法.................................................................................................71.2.4固化及其它处理方法..........................................................................71.2.5多种工艺联合处理法..........................................................................81.3油田压裂废水处理设施及存在问题.............................................................91.4课题研究的目的和内容..............................................................................101.4.1研究意义...........................................................................................101.4.2研究目的...........................................................................................101.4.3研究思路....................................................................