【乙苯制作中的苯蒸出塔的數(shù)據(jù)計(jì)算案例綜述1700字】

乙苯制作中的苯蒸出塔的數(shù)據(jù)計(jì)算案例綜述目錄TOC\o"1-2"\h\u13042乙苯制作中的苯蒸出塔的數(shù)據(jù)計(jì)算案例 1240331苯蒸出塔物料衡算 1189401.1苯蒸出塔物料衡算—清晰分割 115721.2苯蒸出塔操作條件的確定 2150281.3塔底溫度的確定 3252411.4進(jìn)料位置的確定 322551m+n=40 3139002最小回流比的計(jì)算與最小理論板Nmin的計(jì)算 43350采用芬斯克方程式計(jì)算 5276873實(shí)際回流比與理論塔板數(shù) 5157603.1理論塔板數(shù) 5293643.2實(shí)際塔板數(shù)的確定 5142414塔內(nèi)氣、液相負(fù)荷的計(jì)算 5231694.1精餾段(假設(shè)為恒摩爾流) 5217∵V=L+DR=L/D 5299804.2提餾段（假設(shè)為恒摩爾流) 61苯蒸出塔物料衡算1.1苯蒸出塔物料衡算—清晰分割表3-1已知數(shù)據(jù)表(因甲苯含量很少可忽略）組分苯乙苯二乙苯三乙苯合計(jì)Kg/h1919.0321399.966638.97719.6353977.61質(zhì)量/％48.24635.19616.0640.494100.00Kmol/h24.6030120724.76850.121242.6999mol％57.61830.93011.1680.284100.00全塔物料衡算取乙苯為重關(guān)鍵組分苯為輕關(guān)鍵組分塔頂乙苯0.25%(質(zhì)量%)頂壓1.05kg/cm2塔底苯0.25%(質(zhì)量%)底壓1.40kg/cm2則D+W=3977.611919.302=D×(10.25%)+W×0.25%解之得D=1918.681W=2058.929表3-2計(jì)算結(jié)果列表塔頂塔釜組分苯乙苯合計(jì)苯乙苯二乙苯三乙苯合計(jì)Kg/h1913.8844.7971918.6815.14731395.170638.97719.6352058.929質(zhì)量%99.750.25100.000.2567.76231.0340.954100.00Kmol/h24.53700.045324.58230.0660116204.76850.121218.1177mol%99.8160.184100.000.36472.64726.3200.669100.001.2苯蒸出塔操作條件的確定塔頂溫度的確定已知苯蒸出塔塔頂壓力為1.05kg/cm2設(shè)tD=81℃苯、乙苯的飽和蒸汽壓計(jì)算公式(安托因方程)lnP=AB/(T+C)mmHg苯A=15.9008B=2788.51C=52.36乙苯A=16.0195B=3279.47C=-59.95將T=81+2715代入計(jì)算式可得苯、乙苯的和蒸汽壓分別為781.2523、130.6371mmHg表3-3計(jì)算數(shù)據(jù)一覽表組分塔頂氣相組成Ydimol%tD=81℃Pd=1.055kg/cmKi=Pi/PdXi=yDi/Kiαij苯99.8161.011398.6965.9803乙苯0.1840.16911.08801合計(jì)100.0099.784因Σxi近似等于100故塔頂溫度可認(rèn)為81℃1.3塔底溫度的確定已知苯蒸出塔塔底壓力為1.40kg/cm2因無(wú)法查得三乙苯的蒸汽壓，現(xiàn)就用二乙苯的蒸汽壓數(shù)據(jù)代替，計(jì)算之步驟與塔頂溫度的計(jì)算相同二乙苯的安托因常數(shù)為:二乙苯:A=16.1140B=3657.22C=71.18現(xiàn)假設(shè)tw=156℃計(jì)算得到苯、乙苯、二乙苯、三乙苯的飽和蒸汽壓分別為4915.257、1257.4761、364.1062、364.1062mmHg表3-4結(jié)果計(jì)算表組分塔底液相組成ximol%tD=156℃Pd=1.40kg/cm2Ki=Pi/PdYi=Ki×xiαij苯57.6181.563089.9005.2073乙苯30.9300.29969.2681二乙苯11.1680.06450.7200.2153三乙苯0.2840.06450.0180.2153合計(jì)100.0099.906因Σyi近似等于100故塔底溫度就可認(rèn)為156℃1.4進(jìn)料位置的確定在泡點(diǎn)進(jìn)料的情況下可以應(yīng)用下面的半經(jīng)驗(yàn)公式來(lái)確定精餾段和提餾段的板數(shù)。具體如下:n+m=Nm/n={(W/D)(xhf/xjf)(xrw/xad)2}*0.206式中:m—提餾段塔板數(shù)n—精餾段塔板數(shù)。D=1918.681kmol/h、w=2058.929kmol/hXhf=0.30930,xiw=0.00364,xif=0.57618,xad=0.00184m/n={(2058.929/1918.681)(0.30930/0.57618)(0.00364/0.00184)2}*0.206=1.1823m+n=40解之得m=18.3≈18(提餾段板數(shù))、n=21.7≈22(精餾段板數(shù))加料板從頂部數(shù)起的第23塊板進(jìn)料溫度的確定設(shè)進(jìn)料為飽和液體具體步驟同前P=0.5(Pd+Pw)=0.5(1.05+1.4)=1.225kg/cm2假設(shè)t=101.5℃計(jì)算得到苯、乙苯、二乙苯、三乙苯的飽和蒸汽壓分別為1406.1678、270.0371、58.1288、58.1288mmHg表3-5計(jì)算結(jié)果表組分進(jìn)料液相組成ximol%tD=101.5℃P=1.225kg/cm2Ki=Pi/PdYi=Ki×xiαij苯57.6181.563089.9005.2073乙苯30.9300.29969.2681二乙苯11.1680.06450.7200.2153三乙苯0.2840.06450.0180.2153合計(jì)100.0099.906因Σyi近似等于100故塔底溫度就可認(rèn)為101.5℃2最小回流比的計(jì)算與最小理論板Nmin的計(jì)算泡點(diǎn)進(jìn)料q=1最小回流比Rmin的計(jì)算，采用恩德伍德Underwood公式，即Σαijx?/(αij-θ)=1-q=0①Rmin=Σαijx??/(αij-θ)-1②θ為式①的根當(dāng)關(guān)鍵組分相鄰時(shí)，在輕、重關(guān)鍵組分對(duì)基準(zhǔn)組分的相對(duì)揮發(fā)度之間僅有一個(gè)根即α?j<θ<αij之間假定的（i表示輕關(guān)鍵組分、h表示重關(guān)鍵組分)經(jīng)多次度差方能確定即試差到Σαijx?/(αij-θ)=1時(shí)為止。最后試差到2.659表3-6計(jì)算結(jié)果表組分進(jìn)料液相組成ximol%αijαij×x?αij-θαijx??/(αij-θ)苯57.6185.20733.00032.51231,。1492乙苯30.93010.3093-1.695-0.1825二乙苯11.1680.21530.0240-2.4797-0.0097三乙苯0.2840.21530.0006-2.4797-0.0002合計(jì)100.001.0018表3-7對(duì)塔頂物料的計(jì)算結(jié)果表組分塔頂液相組成ximol%αijx??/(αij-θ)苯99.8162.0689乙苯0.184-0.0011合計(jì)100.002.0678所以Rmin=2.06781=1.067采用芬斯克方程式計(jì)算Nmin=Lg{(0.99816/0.00184)?(0.72647/0.00364)?}/Lg3√(5.9803×5.2073×3.9088)-1=6.242塊3實(shí)際回流比與理論塔板數(shù)3.1理論塔板數(shù)首先用捷利蘭(Gilliland)關(guān)聯(lián)圖求出實(shí)際回流比下的理論板數(shù)取R=1.15Rmin=1.15×1.0678=1.2280則(R-Rmin)/(R+1)=(1.2281.0678)/(1.228+1)=0.0719查Gilliland關(guān)聯(lián)圖可得Nmin)/(N+2)=0.56，將Nmin=6.2426代入可得N=16.73塊3.2實(shí)際塔板數(shù)的確定由經(jīng)驗(yàn)值可知E?=42%(板效率)故:N?=N/E?=16.73/42%=39.84塊≈40塊4塔內(nèi)氣、液相負(fù)荷的計(jì)算4.1精餾段(假設(shè)為恒摩爾流)∵V=L+DR=L/D∴L=RD=1.228×24.5823=30.187kmol、V=L+D=(1.228+1)D=54.769kmol為便于計(jì)算,塔頂以純苯計(jì)查得P=1.05kg/cm2、t=81℃時(shí)的苯的物性參數(shù)如下ρl=0.812×10kg/m3ρg=PM/(RT)=1.05×9.807×10*4×10*3×78/(8.314×(2715+81))=2.728kg/m3μl=0.317CP=0.317×103Pa.S、μg=0.0092CP=0.0092×103Pa.Sσl=21.2×103N/m氣體流量Vg=nRT/P=1×8.314×(2715+81)/1.05×9.807×104×103=1566.06m3/h=0.435m3/s液體流量:∵ml=30.187kmol/h=2356.140kg/h∴Vl=m/ρ=2356.140/(0.812×103)=2.902m3/h=8.060×10*4m3/s液氣流動(dòng)參數(shù):Fly=Vi/Vg(ρs/ρg)0.5=2.902/1566.06×(812/2.728)0.5=0.0320選塔板間距Hт=0.450m查圖12-5下冊(cè)P204得C20=0.084m/s氣相負(fù)荷因子為:C=C20{σ/σ20}*0.2=0.084×{21.2×103}*0.2=0.08504.2提餾段（假設(shè)為恒摩爾流)∵是泡點(diǎn)進(jìn)料∴Lˊ=L+F=30.187+42.6999=72.887kmol、Vˊ=V=54.769kmol查得P=1.40k