脱硫设计计算方法

湿式石灰石-石膏法烟气脱硫,设计方法及过程,湿法脱硫设计,1、物料平衡计算：建立物料平衡表烟气平衡脱硫剂（脱硫产物）平衡水平衡,烟气原始参数,确定关键参数,钙硫比脱硫效率液气比石膏品质石灰品质,脱硫剂的选取,脱硫剂矿源品位脱硫剂的物理化学特性：真实密度、堆积密度、粒径分布、空隙率、分形、比表面积、活性、吸硫特性影响脱硫剂吸硫特性的因素：水份、温度、浓度、脱硫剂物理特性,2、建立工艺流程图,与物料平衡表同时,3、关键控制回路,烟气量、烟气中二氧化硫浓度及钙硫比控制进浆量pH值调节,4、脱硫反应塔,上升速度停留时间液气比pH值循环浆液浓度液柱高度脱硫能力搅拌防腐蚀防堵塞,氧化曝气装置,循环氧化槽的容量氧化空气的停留时间氧化空气的过量系数氧化空气的压力、温度循环浆液的pH值CaSO3的结晶与CaSO4结晶氧化曝气装置的防堵塞氧化曝气装置的防腐蚀,浆液喷射装置,浆液流量的调节喷嘴的特殊结构浆液管道的防腐蚀浆液管道的防堵、防垢,5、平面布置,烟气脱硫过程,设计计算,烟气平衡,燃煤/烟气组份,输入数据机组容量300MWel燃煤热值(Hu)20.600kJ/kg全厂效率41,3%含硫量0,79%假定:1kg煤8,5Nm(wet)烟气含水量7,2%,燃煤烟气组份,燃烧计算,燃煤烟气成分,水蒸汽密度,烟气密度assumeddataDensityfluegas1,35kg/Nm质量流量,燃煤烟气成分,化学过程输入数据SO2removalefficiency95%Sproportionincoal0,79%Coal127t/hS+O2=SO2Noteatomicmass:S=32g/molO=16g/molCa=40g/molC=12g/molH=1g/mol,燃煤烟气成分,SO2production&removal,燃煤烟气成分,SO2-contentInputdataassumeddataO2contentindrygas7%,燃煤烟气成分,SO2contentat6%O2,燃煤烟气成分,吸收塔热动力学/绝热饱和,假定电除尘器出口温度138CGGH出口温度108C干烟气中水含量计算,在h,x图上,108C和0,046kg/kg,dry的交点的焓h=233kJ/kg.沿等焓线到饱和线可得到饱和温度,吸收塔热动力学/绝热饱和,Thermodynamicsforscrubber/adiabaticsaturation,吸收塔出口净烟气,吸收塔热动力学/绝热饱和,烟气计算结果,AbsorberINLET,AbsorberOUTLET,液相平衡,13%wt,50%wt,3%wt,石灰石消耗/石膏产量,1SO2+1CaCO3+2H2O+1/2O2CaSO42H2O+CO2Notemolarmass:SO2=64g/molCaCO3=100g/molH2O=18g/molCO2=44g/molO2=32g/molCaSO42H2O=172g/molExample:Afluegasdesulphurisationplantwith2t/hSO2-emissionsneeds:andproduces:,水平衡,废水(a)keepCl-level15to20g/l(b)keepsulfatelevel35g/l(b)keepash+inertlevelinabsorberslurry13%WastewaterflowbasedonCl-levelInput(assumption):DatafromexperienceHCl-removal98%,废水流量,水平衡,工艺水消耗Sumof:WaterforfluegassaturationWastewaterMoisturegypsum+crystalwaterDropletemission(negligible),水平衡,石膏脱水,Forthescrubbingandcrystallizationprocessintheabsorber,thegypsumsolidcontentisbetween5and20%.Inputassumeddata,石膏浆液的密度,石膏脱水,旋流器底流密度旋流器顶流密度,石膏脱水,石膏产量,石膏脱水,水力旋流器,4,7assumptionrelatedto13%solidsintheflowfromtheabsorber,3%solidsinthecycloneoverflowand50%solidsinthecycloneunderflow,石膏脱水,吸收塔来石膏浆液,石膏脱水,石膏脱水,水力旋流器顶流成分(假定)50%ofsolidsisgypsum25%ofsolidsisash25%ofsolidsislimestone,石膏脱水,石灰石浆液供给,石灰石消耗石灰石浆液密度石灰石固体密度石灰石浆液质量流量,石灰石浆液密度石灰石浆液体积流量,石灰石浆液供给,浆池尺寸,浆液罐的停留时间浆液罐体积,(假定),(假定),滤液箱尺寸,滤布冲洗水量石膏冲洗水量take50%fromgypsummassflow(assumption)滤液量,滤液箱停留时间(假定)滤液箱容积,(assumption),滤液箱尺寸,吸收塔尺寸,烟气流量SO2浓度SO2-脱硫率液气比:L/G=12l/Amatabsorberoutlet(假定),吸收塔循环浆液流量及每泵的流量Absorbertemperature=48C喷淋层数(pumps)=3,吸收塔尺寸,吸收塔直径吸收塔烟气流速w=3,7m/s(assumption)吸收塔循环区体积循环浆液停留时间t=4,3min(assumption),吸收塔尺寸,吸收塔循环浆液区高度Sumpheight11,9mHeighttillfluegasduct1,5mFluegasductheight4,0mHeighttofirstspraybank(fromfluegasduct)2,5mSprayingbanks:2x1,5m3,0mHeighttillmisteliminator1,3mHeightoftwostagedropletseparators2,5mHeightfluegasoutletduct3,0mSum29,7mTotalabsorberheight:H=30m,吸收塔尺寸,增压风机和循环泵的能耗,增压风机吸收塔压损(assumption)10mbarGGH压损12mbar烟道压损7mbar总压损29mbarSpecificfluegastransportworkForboosterfanwith85%effectiveness,功率消耗Pumpefficiency=0,89Volumeflow(pump)=5.300m/hLiquidlevel=11,9mGeod.height=1,5m+4,0m+2,5m+1,5m=9,5mPressureatnozzles=10m(1bar)Pressureheightpipes=3msum=22,5m,增压风机和循环泵的能耗,中间层泵的能耗三层泵的总能耗,增压风机和循环泵的能耗,烟道尺寸,净烟气烟道直径Fluegasvelocityw=18m/s(assumption)Saturatedcleangas原烟气烟道直径,管道计算,1)石灰石浆液输送管Particlesizelimestone=90%44md5015mConcentration30%totalsolidsamountTransportvelocity6xsettlingvelocityNormallywtransport2,5m/sVolumeflowsuspension=8m/h石灰石浆液输送管直径,石灰石浆液循环管直径Volumeflowcirculation2Vsuspension(Absorber),管道计算,2)石膏浆液管径Particlesizegypsumd50=3550mTransportvelocity6xsettingvelocityNormallywtransport2,5m/s至旋流器石膏浆液管径,管道计算,氧化风计算,强制氧化SO2+H2OHSO3-+H+HSO3-+O2SO42-+H+1molSO2needsmolO21kgSO2needs32:2/64kgO2StoichiometricfactorforO2-absorptioninabsorbersump2,5specificweightO2:,O2体积:空气体积:,氧化风计算,氧化风压头Injectionpointinabsorber:distancetoliquidlevel=6m,氧化风计算,吸收塔搅拌器计算,Needofenergyforagitating80W/melAbsorbersumpvolume865mAgitatorcapacityPel=865mx80W/m=69kWNumberofagitators4能耗及搅拌器,石灰石粉仓计算,Capacityforlimestonesilo7days(assumption)Maximumdensity1.400kg/mNormaldensity1.000kg/mLimestoneconsumption2,97t/hStoragevolume,石膏仓计算,Capacityforgypsumstorage5days(assumption)Normaldensity1.000kg/mGypsumproduction5,11t/hdry5,11/0,9=5,7t/hwet(10%moisture)存储容积,真空带式脱水计算,过滤面积1mforagypsumproductionof1t/hdry(assumption)GypsumproductionFilterarea=5,1m(noredundance)真空带式脱水机容量Install2filterswitheach70%ofmaximalcapacity2x70%completefilterarea2x