制盐工艺流程Word格式文档下载.docx
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制盐工艺流程Word格式文档下载.docx
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2.工艺流程简述
卤水经滩田日晒蒸发,至饱和后引入一个卤水库中储存。
卤水库的作用,一是储存一定量的饱和卤水,以备真空制盐生产的需要;
二是卤水在此有一定的停留时间,可以使其中的一些杂质颗粒沉淀下来,达到净化卤水的目的。
净化后的饱和卤水从卤水库引出后,进入蒸发制盐车间的精卤桶。
采用预热后的卤水进罐,顺流转料、末效排盐浆,集中排母液的方式进行生产。
I效蒸发罐盐箱中的盐排到II效下循环管中,II效盐箱中的盐排到III效下循环管中,III效盐箱中的盐排到IV效下循环管中,最后集中在IV效盐箱;
IV效排出盐浆,同时由IV效分离罐排出母液。
工艺流程简图见图1。
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3.工艺的优缺点
运用该工艺已在中国北方建设了一个年产15万吨的真空制盐生产线,相比再制盐生产工艺,其实施效果如下:
本工艺采用饱和卤水制盐,不需要淡水化原盐,淡水消耗低,可节约淡水资源,根据生产情况,1t盐消耗淡水1.4-0.2m3,而再制盐生产工艺需要淡水3.5-4.53.73
m3,吨盐节约了2.1-4.3m3淡水。
2)节约日晒盐场土地,减少原盐消耗,提高了盐田利用率
对再制盐生产线来说,一般生产1t精制盐需要消耗1.2t日晒原盐,年产15万t的精制盐需要18万t原盐,需要结晶面积136.36公顷(按目前中国北方盐场有效结晶单产1650t/公顷,有效面积占80,),采用饱和卤水直接进蒸发罐工艺,不需要饱和卤水进结晶池继续蒸发制盐,只需要建设一个约2公顷的饱和卤库,因此,节约了土地面积134.36公顷,节省的结晶面积可用于增加日晒盐产量8547t,按日晒盐销售价160元/t计算,日晒盐增加产值136.8万元。
如果土地按3万元/亩计算,节约土地价值为6000多万元。
3)采用三次洗涤方法洗涤盐浆以去除钙镁离子,使氯化钠含量超过99.4,,精制盐达到优级盐质量。
蒸发结晶过程中盐浆会夹带大量的母液,母液中含有大量的钙、镁杂质,因此,采用三次不同的洗涤方式洗涤盐浆,提高精制盐质量。
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4)用饱和卤水直接生产精制盐母液损失小,提高了母液的利用率,实现盐化联产
采用盐田饱和卤水直接生产优级真空精制盐工艺,每产1t精制盐副产母液约1.7m3,以年产15万t精制盐计算,全年可产生25.5万m3蒸发母液,且排出的苦卤氯化钾含量达到了24,30g/l,浓度为29,34?
Be?
,钠镁比值为1.4,0.6,排出的苦卤中氯化钾总含量为6589t,氯化镁总量为36540t,硫酸镁总量为18900t,氯化钠总量为37600t,溴总量510t。
而年产18万t原盐,排出的苦卤量一般只有18万m3,经过复晒、渗透损失、沟道输送进入化工厂后只有原来的45,左右,也就是说还有8.1万m3,这时氯化钾总含量为2036t,氯化镁总量为15280t,硫酸镁总量为7727.4t,氯化钠总量为11128t,溴总量162t。
因此,该工艺可为盐化工生产提供更多的原料,提高了生产效率,降低了各种消耗,节约能源。
该工艺排出的制盐蒸发母液温度在55.04?
以上,可通过管道直接进入下步生产氯化钾的工序,生产氯化钾产品,节约氯化钾生产过程中所需热量,折标煤1157吨/年
5)由于滩田饱和卤水较化盐卤水氯化钠含量低,因此单位产品的蒸发水量较高,吨盐产品电、蒸汽消耗量较大,能耗较高。
6)蒸发设备换热面积较化盐溶解工艺稍高,因此设备投资相对较高,但由于节省大量盐田结晶面积,总体投资低。
4.与原盐溶解再制盐工艺技术经济指标比较
国主要经济技术指标比较
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两种工艺在投资和单位产品生产成本中有较大的差别,饱和卤水法单位产品总投资低于原盐溶解法,单位产品成本低于原盐溶解法30,。
5.结论
对于北方海盐区生产精制盐企业来说,利用滩田饱和卤水直接进蒸发罐制取精制盐是一个较好的生产工艺,节约投资,节约土地,特别是将宝贵的原盐溶解成饱和卤水再进行制盐是对土地资源的浪费,再有其生产成本低,企业有较高的利
润空间;
排出的制盐母液综合利用生产钾、溴、镁等产品,使卤水全部吃干榨净,
没有废物排放,减少了环境污染,有利于可持续发展。
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Newtechnologyofproducingrefinedsaltbyaddingsaltfield
saturatedbrineintoevaporatordirectly
JinzhilingGeJinyang
(SaltResearchInstituteChinaNaturalSaltIndustryCorporation,TianJin300450)
Abstract:
AfterMakingsalinesaturatedbrineflowinevaporatingpot,thesodiumchlorideisobtainedbyevaporativecrystallization.Calciumandmagnesiumionscanberemovedbywashingsaltthreetimesinordertogetthesodiumchloridethatthepurityisover99.1percentandthemotherliquorthathavehighconcentration.
Keywords:
salinesaturatedbrine,vacuum,refinesalt
magnesiumchlorideetc.inorderto
makeuseofallkindsofeffective1BRIEFINTRODUCTION
constituentsinthebrineandachievethe
Atpresent,thematerialsofmakingobjectsofnodischarge,nopollutionandvacuumsaltareusingthewellandrockcirculatingeconomy.
saltinmostofthewellandrocksalt
corporationsandthesaturatedbrinegot2.INDICATIONOFTHEbydissolvingcrudesalt.AlongwiththePROCESSFLOW
rapiddevelopmentofcausticalkaliand
sodiumcarbonateandthegrowthintheAfterbeingsolarizedtosaturationpeople’s
livingstandard,theinbeachfieldbrinewasinductedtocontradictionofcrudesaltinsupplyandbrinetankandstored.Ontheonehandrequireismoreandmorestoodout.brinetankcanstoresomesaturatedbrine
Particularlyintheseasaltareas,thatisusedtoproducevacuumsalt.Onproductingrefinesaltwithsaturatedtheotherhand,brinehavesomebrinethatisgotbydissolvingcrudesaltresidencetimeheresosomeimpuritiescanincreasetheconsumptionofrawcanbedepositedinordertomakethesalt,reducetheavailabilityfactorofsaltbrinebepurified.Afterbeingdrawoutedfield,addinvestmentandproductionfrombrinetankthecleanedsaturatedcost.Thiswillinfluencetheeconomicbrinewaspumpedtofinebrinetankinefficiencyofediblesaltmanufacturingthemanufacturesaltplant.Andenterprises,makethemreduceoutputproductioncanbegoneonbyusingtheandaffectpeople’slive.methodsof
preheatingbrine,
However,usingthemethodoftransferringstuffinparallelflow,makingsaline
saturatedbrineflowindischargingsaltslurryinthelasteffectevaporatingpotandthenobtainingandexportingmotherliquorsodiumchloridebyevaporativeconcentratedly.Thesaltinthefirsteffectcrystallizationcansavingcrystalarea.tankisdischargedtothecirculationpipeFurthermore,themotherliquorcanbeofthesecondeffect,Thesaltintheusedasmaterialtoproducechemicallysecondeffecttankisdischargedtotheproductssuchaspotassiumchloride,circulationpipeofthethirdeffect,The5
saltinthethirdeffecttankisdischargedtothecirculationpipeofthefourtheffect.Atlastthesaltiscollectedinthe
fourtheffecttankwherethesaltslurryandthemotherliquoraredischarged.Fig.1isthediagramoftheprocessflow.
Figure.1Diagramoftheprocessflow
3.RELATIVEMERITSOFTHEPROCESS
InthenorthofChinaaproductionlinehasbeenbuiltwiththisprocess,whichcanproduce1.5milliontonssaltperyear.Comparingwithreworksaltproductionprocess,theeffectofthisprocessisasfollows:
1)Thesaturatedbrineisusedinthisprocesstaketheplaceofdissolvingcrudesaltwithfreshwater.Suchcanreducetheconsumptionoffreshwaterandsavetheresource.Accordingtotheproduceconditions,producing1tonsaltwillconsume1.4-0.2m3freshwater.Andthatifusethereworkingsaltprocess3.5-4.53m3freshwaterwillbeused.Thatistosay2.1-4.3m3freshwatercanbesavedcorrespondingto1tonsalt.
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2)Savingthesolarsaltfield,reducetheconsumptionofcrudesalt,increasetheavailabilityofthesaltfield.
Forthereworkingsaltproductionline,asageneralruleproducing1tonrefinesaltwillconsume1.2tonssolarsalt.Producing1.5milliontonrefinesaltneeds1.8milliontonscrudesaltand136.36hectarecrystalarea(Accordingtotheexperiencethatonehectarecanproduce1650toncrystalandtheeffectiveareais80percent).Usingtheprocessthatthesaturatedbrineispumpedtoevaporatingtankdirectlythebrineneednotevaporateincrystalpondbutforasaturatedbrinestoreroomofabout2hectare.Suchcansavesurfaceareaof134.36hectareandthisareacanbeusedtoincrease8547tonoutputofsolarsalt.Hencetheproductivevalueofsolarsaltwillincrease136.8ten
thousandyuanaccordingtothemarketpriceofsolarsaltwhichis160yuan/t.Andlandvalueof60millionyuancanbesavedifthelandis30,000yuanpermou.
3)Adoptingthemethodofwashingsaltthreetimesinordertogetridofcalciumandmagnesiumions,makethepurityofsodiumchlorideexceed99.4%andmaketherefinesaltreachfirstquality.Intheprocessofevaporativecrystallizationmuchmotherliquorwillexistinsaltslurry.Themotherliquorcontainsalotofimpurityofcalciumandmagnesium.Sosaltslurryiswashedinthreedifferentwaysinordertoimprovethequalityofrefinesalt.
4)Usingthesaturatedbrinetoproducerefinesaltcanreducetheconsumeofmotherliquors,enhanceit’savailabilityandrealizetheproductionofsaltandchemicalstogether.
Theprocessthatproducingexcellentvacuumsaltwithsalinasaturatedbrinedirectlycanget1.7m3motherliquorinrelationto1trefinesalt.Onthebaseof150,000tonrefinesalt,wecanget255,000m3evaporationmotherliquor.Inbitterbrinewhoseconcentrationis29,340Be?
thecontentofpotassiumchlorideis24,
30g/landtheratioofsodiumandmagnesiumis1.4,0.6.And6589tpotassium
chloride,36540tmagnesiumchloride,18900tmagnesiumsulfate,37600tsodiumchlorideand510tbrominearecontainedinthebitterbrine.Thebitterbrineisabout180,000m3inrelationto180,000tcrudesalt.Afterbeingsolarizedrepeatedlyandconsumingforfilterthebrineisleft45%whenitispumpedtochemicalplant.Thatistosaythereare81,000m3brine.Bynowthereare2036tpotassiumchloride,15280tmagnesiumchloride,
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7727.4tmagnesiumsulfate,11128tsodiumchlorideand162tbromine.Sotheprocesscanprovidemorematerialforsaltandchemicalsplants,heightenproductionefficiency,reduceallkindsofconsumptionandsaveenergy.Thetemperatureofthemotherliquorgotfromthisprocessisover55.04?
.Soitcanbepumpedtothe
potassiumchlorideprocesswithpipetoproducepotassiumchloride.Suchwillsavetheheatquantityintheprocessofproducingpotassiumchloride.Andtheheatquantityisequalto11578t/ystandardcoal.
5)Becausethecontentofsodiumchlorideinthebeachsaturatedbrineislowerthanthecontentinthebrinethatisgotbydissolvingsalt,theevaporatedwaterofunitproduceishigher,theelectricityandsteamconsumptionaremore.Thatistosaytheenergyconsumptionishigher.
6)Theheatexchangeareaisalittlerbiggerthantheprocessofdissolvingsalt,sotheequipmentinvestmentishigher.Butbecauseofsavingalotofsalinacrystalareathetotalinvestmentislower.
4.COMPARETHEECONOMICINDICATORSWITHTHEPROCESSOF
DISSOLVINGCRUDESALTANDTHENREMAKINGSALT
InChinaTherearetwomainmethodstoproducingvacuumsaltinseasaltarea.Oneispumpingthebeachsaturatedbrineintoevaporatingpot.Theotherisusingthesaturatedbrinegotbydissolvingcrudesalt.Comparingthesecondmethodwiththe
firstmethodthe
relativemeritsofthesecondmethodisasfollows:
(1)needtobuildcrystalpondand
thetotalinvestmentishigher.
(2)Theevaporatedwaterofunitproductissmallerandtheequipmentinvestmentislower.(3)Theconsumingofelectricity
andsteamislower.(4)Theconsu
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