分離工程精餾塔

《分離工程》課程設(shè)計(jì)班級(jí):姓名:專業(yè):課程名稱:指導(dǎo)老師:目錄一、設(shè)計(jì)目的和要求二、設(shè)計(jì)題目三、工藝流程的確定四、操作條件確定五、塔的物料恒算六、塔的工藝條件計(jì)算七、物性數(shù)據(jù)計(jì)算八、精餾氣液負(fù)荷計(jì)算九、塔和塔板主要尺寸計(jì)算十、溢流裝置計(jì)算十一、板式塔篩板流體力學(xué)計(jì)算十二、塔板負(fù)荷性能圖十三、冷凝器和再沸器熱量衡算十四、附屬設(shè)備計(jì)算及選取十五、設(shè)計(jì)結(jié)果總結(jié)表十六、設(shè)計(jì)過(guò)程參數(shù)總結(jié)十七、流程圖及設(shè)備圖（一）設(shè)計(jì)目的與要求使學(xué)生更加熟悉工程設(shè)計(jì)基本內(nèi)容，掌握化工設(shè)計(jì)的主要程序及方法。鍛煉和提高學(xué)生綜合運(yùn)用理論知識(shí)和技能的能力，收集和查閱資料的能力，分析和解決工程實(shí)際問(wèn)題的能力，獨(dú)立工作和創(chuàng)新的能力。（二）設(shè)計(jì)題目烴化液精餾系統(tǒng)設(shè)計(jì)設(shè)計(jì)內(nèi)容料液的組成如下表所示:組分名稱苯甲苯已苯丙苯丁苯摩爾分?jǐn)?shù)0.150.350.200.200.10料液的溫度為60°C，摩爾流量為100Kmol/h公用工程條件為：加熱蒸汽等級(jí)0.9Mpa（絕壓），循環(huán)冷卻水30C;電容量可滿足要求。分離要求：塔頂流出液中已苯濃度為3%（摩爾分?jǐn)?shù)），釜液中甲苯濃度為1%。（三）工藝流程的確定烴化液混合物經(jīng)過(guò)預(yù)熱器預(yù)熱到60C后，送入精餾塔。塔頂上升蒸汽采用全凝器冷凝，一部分作為回流液，其余為塔頂產(chǎn)品經(jīng)冷凝器冷凝后送入貯槽，塔釜采用間接蒸汽再沸器供熱，塔底產(chǎn)品經(jīng)冷凝后送入貯槽。流程圖為附圖。（四）操作條件確定操作壓力有設(shè)計(jì)經(jīng)驗(yàn)知芳烴混合物操作壓力一般低于202Kpa，所以選擇常壓101.325Kpa為操作壓力。進(jìn)料溫度由已知條件只進(jìn)料溫度為60C.進(jìn)料熱狀況選擇由進(jìn)料溫度及壓力確定進(jìn)料熱狀況為過(guò)冷液體進(jìn)料。加熱劑選擇由給定的條件用0.9Mpa的蒸汽作為加熱劑。冷卻劑選擇冷卻水作為冷卻劑。（五）精餾塔的物料恒算輕重關(guān)鍵組份的確定由所給的原料組成及分離要求，可分析出甲苯為輕關(guān)鍵組分，已苯為重關(guān)鍵組份。塔頂塔底物料組成及塔頂塔底溫度計(jì)算。1）K值的計(jì)算

因?yàn)椴僮鲏毫θ闃?biāo)準(zhǔn)大氣壓101.325Kpa，所以可按理想流體計(jì)算平衡常數(shù)K。:由p0L_plgp0"BiT+C（安托尼方程）由化工熱力學(xué)附表查出相關(guān)參數(shù)如下表:組分ABC△T/K苯6.068321326.034-48.99353422甲苯6.050431327.6255.526286-—410乙苯6.069911416.922-60.716298-—420丙苯6.076641491.8-65.9234-455丁苯6.103451575.47-71.95343-4862）用試差法計(jì)算塔頂溫度假設(shè)塔頂溫度為377.15K，按理想切割的組成進(jìn)行計(jì)算。組分苯甲苯￡di153550ydi0.30.71ki1.97720.8258xi0.15170.84770.9994由試差結(jié)果符合要求，故設(shè)塔頂溫度為377.15K正確。3）用試差法計(jì)算塔底溫度假設(shè)塔底溫度為424.15K，按理想切割的組成進(jìn)行計(jì)算。組分乙苯丙苯丁苯￡wi20201050xwi0.40.40.21kwi1.46390.80680.4212yi0.58560.32270.08420.992541因I所以所設(shè)溫度424.15K正確。按理想清晰分割法確定塔頂塔底產(chǎn)品分布量塔頂量：D=100X(0.15+0.35)=50Kmol/h塔底量：W=100X(0.2+0.2+0.1)=50Kmol為避免計(jì)算后關(guān)鍵組分濃度超過(guò)限度值，dh和wl采用的計(jì)算濃度值應(yīng)略小于規(guī)定值。dh=3%X0.9X50=1.35Kmol/h貝Uwh=100X0.2-1.35=18.65Kmolwl=1%X0.9X50=0.45Kmol/h則dl=100X0.35-0.45=34.55Kmol/h所以(d/w)h=1?35/18?65=0.0724(d/w)=34.55/0.45=76.7778求以中關(guān)鍵組分乙苯為對(duì)比組分，各組分的平均相對(duì)揮發(fā)度，用泡點(diǎn)方程計(jì)算列表如下：組分苯甲苯乙苯丙苯丁苯kDi(377.15k)1.97720.82580.38590.18970.0862aihD5.12392.140010.49150.2235Kwi5.86032.77441.46390.80680.4212aihW4.00321.895210.55120.2877aih4.52902.013410.52050.2536代入漢斯特別克公式，解下列方程logd/w)=logd/w)+lo紋h/loga/hlogd/w)-logd/w)]二—1.140%10.1460logh1i將各組分的平均相對(duì)揮發(fā)度dh代入上式，求出(d/w)i進(jìn)一步求出di，wi，xDi，xWi。列表如下：組分苯甲苯乙苯丙苯丁苯Laih4.5902.013410.52050.2536(d/w)i2.44x10576.77780.07240.00018.50X1依

fi1535202010100di1534.551.350.00228.50510750.9022Wi6.140.4518.6519.99781049.0979xDi0.29470.67880.02654.284051.6*1081Xwi1.254060.00920.3790.40730.20371由上表得到XDh=0.0265<3%xWl=0.0092<1%均小于規(guī)定濃度值符合要求。6）確定塔頂溫度和塔底溫度設(shè)塔頂溫度為378.15K時(shí)組分苯甲苯乙苯Eydi0.29470.67880.02650.99996ki2.03000.85050.3986xi0.14520.79810.066541.0098所設(shè)溫度378.5°C正確。設(shè)塔底溫度為424.15K組分甲苯乙苯丙苯丁苯Exwi0.00920.37990.40730.20371ki2.77441.46390.8068490.4212yi0.02540.55600.3286340.08580.9959所設(shè)塔底溫度為424.15K正確。7）檢驗(yàn)各組分相對(duì)揮發(fā)度與估算值是否一致塔頂溫度驗(yàn)算alh假設(shè)=2.140alh計(jì)算=0.8505/0.3986=2.1337（alh假設(shè)-alh計(jì)算）/alh計(jì)算=（2.140-2.1337）/2.1337=0.29%<5%所以說(shuō)算正確因塔底所設(shè)溫度與計(jì)算溫度相同，不用驗(yàn)算。塔的工藝條件計(jì)算最小理論塔板數(shù)(用芬斯克方程)本設(shè)計(jì)采用全凝器Nlog[(xl/xh)*(xh/xl)]logaIh(xl/xh)=25.5926(xh/xl)D=41.4444logalh=3.0256計(jì)算得：Nm=9.9513最小回流比的計(jì)算求算進(jìn)料的氣化分率由已知進(jìn)料溫度60°C,操作壓力為101.325Kpa，取?料壓力為101.325Kpa,設(shè)氣化率為0.平均溫度t=U2(tD+tW)=401.15K以重關(guān)鍵組分乙苯為對(duì)比組分，求相對(duì)揮發(fā)度ai已知：p=101.325KpaT=401.35K0=1.2172組分i苯甲苯乙苯丙苯丁苯求和Ki3.57061.59770.79820.41790.2051ai4.47332.001610.52360.2570Zi0.150.350.20.20.110.20610.8931-0.9208-0.1510-0.026760.000615▽ai*zi用試差法計(jì)算出當(dāng)Zai_q=e時(shí)0值為1.2172正確。d1_vai*xDi則，Rm+1=Z以i—0=2.0147Rm=2.0147-1=1.0147操作回流比：R=1.5Rm=1.5221理論板數(shù)確定j=(N-N)/(N+1)x=(R-R}/(R+1)=(1.530-1.020)/(1.530+1)令=0.2016"查吉利蘭圖得y=0.40則Nt=17.25214)總版效率：由j=0.4級(jí)(lh^*L0.)24alh=2.0016t=128°C組分苯甲苯乙苯內(nèi)苯丁苯求和XFi0.150.350.20.20.11ui0.180.210.230.297450.3447ul0.0270.07350.0460.059490.034470.24046則，效率門=0.5861Na=（%—1）/門=27.7274=285）進(jìn)料未知的確定由N=n+m-4解得n/m=0.6262所以n=7.2583m=9.9938則精餾段=（n-1）/門=10.6771圓整為11塊塔板提留段=m/門=17.0503圓整為17塊塔板（七）物性數(shù)據(jù)計(jì)算1)全塔平均溫度t=（424.15+378.15）/2=401.15K2）平均分子量的計(jì)算組成苯甲苯乙苯內(nèi)苯J苯￡分子量M78.115294.1424106.169120.1986134.224塔頂yi0.29470.67880.02650.999957塔頂對(duì)應(yīng)xi0.14520.79810.06651.009797

塔底xi1.25105E-060.00920.37990.40730.20371由Mvd=LMi*yi=89.7344kg/kmolMld=LMi*xi=93.5382kg/kmolMvm=112.4479kg/kmolMlm=117.4872kg/kmol所以Mv=101.0912kg/kmolMl=105.5127kg/kmol3）液相平均密度piv依下式：1/p=ZQiP（（ai為質(zhì)量分?jǐn)?shù)）組分苯甲苯乙苯丙苯」苯128°C0.7450.760.7650.7655105°C0.7850.790.790.79151C0.720.740.7490.75yi*m23.0192098263.89942.8158和0.6240.790.7489.73439ai頂0.2565260720.71210.0314001ai進(jìn)1.25105E-06P頂=788.7113kg/m30.00920.3799p底=731.4856kg/m30.40730.20371塔底yi7.3315E-060.02540.55610.32860.08580.995926Plv=760.0984kg/m34）氣相平均密度PmVp=虬=101.3號(hào)101=°3907炊2m3/mVRT8.31x0401.15bm頂=18.8916mN/mmbbm底=17.99989mN/mm=1/2（m頂+°bm頂=18.8916mN/mmbbm底=17.99989mN/mm=1/2（m頂+°m底）=18.44576mN/m溫度苯甲苯乙苯丙苯丁苯128C15.716.517.818.0218.4105C18.51920.520.520.62151C1314161615.95bm底1.96415E-050.1512296.7613927.3396387683.747615687bm頂5.45163273812.89630.5436900

精餾氣液負(fù)荷計(jì)算V=(R+1)D=(1.5221+1)50.9022=128.3779kmol/h憐地=12&3冏9質(zhì)1』9】1晶力/360Q36003.0712VL=RD=1.5221X50.9022=77.4758kmol/h,LM77.47:58105.5127^rLs===0.0029874h/360Q3600760.0984Lh=3600XLs=10.7548m3/h塔徑尺寸計(jì)算初選塔板間距為HT=0.41m,取板上液層高h(yuǎn)l=0.06m算pvP76算pvP760.09841/2=)3T07120.040039?18.44576mN/h查Smith關(guān)聯(lián)圖得C20=0.072，依式C=C20(希)0龍校18.44576mN/h時(shí)的C,即C=C(二)0.2=0.072(18.44576)0=0.074202020廠IP-p760-09-843.0712u=C=0.0743；0712=1.07023/取安全系數(shù)為0.70,則u=0.70=0.：01.1=123777858/max4VS;~4x1.17381故DJ飛3.1義0.771583878圓整為DT.4m則空塔氣速為u=0.762891m/s(十)溢流裝置計(jì)算采用單溢流，弓形降液管，平行受液盤及平行溢流堰，不設(shè)進(jìn)口堰，個(gè)計(jì)算尺寸如下。1)溢流堰長(zhǎng)lw取堰長(zhǎng)lw為0.60D，即Lw=0.60X1.4=0.84m2)出口堰高h(yuǎn)w由h=h-h

，查液流收縮計(jì)算圖，得E=1.045，依下式(Lh/1)2.5=16.6304TOC\o"1-5"\h\z2.84L\o"CurrentDocument"h=E(—h.)2/3-100012.8410.7548，查液流收縮計(jì)算圖，得E=1.045，依下式=x1.045()2/3=0.01624m\o"CurrentDocument"10000.84故hw=0.06-0.01624=0.04376m3)降液管的寬度Wd與降液管面積Af由lw/D=0.60，查弓形降液管寬度與面積圖得Wd/D=0.098,Af/At=0.055故Wd=0.098D=0.098X1.4=0.1372m兀3.14…At=D2=x14=1.538644Af=0.055X1.5386m2T由式=AH=0.084&°.41=11.613&50.002987符合要求T由式s4)取液體通過(guò)降液管底隙的流速降液管底隙高度h0h=h-0.00&0.04歹760=006m).037764)取液體通過(guò)降液管底隙的流速5)塔板的布置取安定去寬度Ws=0.07m，邊緣區(qū)寬度Wc=0.03m依下式計(jì)算開孔區(qū)面積.1A=2x」R2—二2+R2si-11aV180Rg1=D-(W+W)=U-(0.1*72=07)0.4928式中2ds'2R=D-W=U-0.0=0.672c2由以上算得：Aa=1.2714m26)篩孔數(shù)n與開孔率取篩孔的孔徑d0為5mm，正三角形排列，用5=3mm的碳素鋼作為篩板，取t/do=4.0,故孔中心距t=4.0X5.0=15.0mm

1158x103依式n=(——-——)Aa=3681孔0.907__%=5.6688%(20/5)2A宓0.907宓依式甲=才％=E%=a0(在5~15%范圍內(nèi))每層塔板上的開孔面積A0為1.27=14On0721A=中A=0.0567氣體通過(guò)篩孔的氣速V1.1738u0.907__%=5.6688%(20/5)21.27=14On0721(十一)篩板的流體力學(xué)計(jì)算1)氣體通過(guò)液體壓降相當(dāng)?shù)囊褐遠(yuǎn)p依式h=h+h+hpcLb干板壓降的液柱高h(yuǎn)c依叩"再由式5/依叩"再由式5/31.,67查干板孔的流量系數(shù)圖得，C0=0.84h=0.051(力)2(J)Cph=0.051(=0.051X(16^；2X(3.0712)=0.0775m1.6667760.0984氣流通過(guò)板上液層壓降相當(dāng)?shù)囊褐叨萮lV1.1738u=s==0.807m/saA-Af1.5386-0.0846F=u/=0.807330712=1.4048由充氣系數(shù)^0與Fa的關(guān)聯(lián)圖差得板上液層充氣系數(shù)為0?65依式h30(h+4)=0?65<(0.043760?0162兮0?03功克服液體表面張力壓降相當(dāng)?shù)囊褐鵫b

74b4x18.4458h===0.00197珈據(jù)式bp,xgxd0760.0984<9.81x0.005故hp=0.0775+0.039+0.001979=0.11844mm單板壓降霧膜夾帶量ev的驗(yàn)算_5.7x10-6(u—(H二h325.7x10-60.8073()3.2=霧膜夾帶量ev的驗(yàn)算_5.7x10-6(u—(H二h325.7x10-60.8073()3.2=0.011618.4458x10-30.41-0.150.0116kg液/kg氣<0?1kg液/kg氣故在設(shè)計(jì)負(fù)荷下不會(huì)發(fā)生過(guò)量霧膜夾帶。漏液的驗(yàn)算=4.4C0J(0.0056b0.1叱-h加七/p.依下式=4.4x0.8&：(0.005缶0.13<0.06-0.001979)760.0984.0712由式=6.2139k/su16.2862篩板的穩(wěn)定系數(shù)K=產(chǎn)=6.213=92.62O〉9(1.5)故在設(shè)計(jì)負(fù)荷下不會(huì)產(chǎn)生過(guò)量漏液。4)液泛驗(yàn)算為防止降液管液泛的發(fā)生，應(yīng)使降液管中清液層高度七<0(Ht+h)h=h+h+h依式apLd計(jì)算Hdhd依下式計(jì)算，即h=0.153(Ls)2=0.153(0.002987)2=0.158799kdT~xW0.84x0.0378H=0.11840.039b0.00135=0.15879k取0=05，則0(Ht+h)=0.5(0.4沖0.04376：=0.226879>氣

在設(shè)計(jì)負(fù)荷下不會(huì)發(fā)生液泛現(xiàn)象。根據(jù)以上驗(yàn)算，可以認(rèn)為精餾塔徑及各工藝尺寸使合適的。（十二）塔板負(fù)荷性能圖1）霧膜夾帶線（1）依式5.7RO,u、

ev=(a)3；H-hTf式中Vu=saA—ATfs=0.68V81.53—60.0846s氣=2.5(h+h)=2.5h+2.84x在設(shè)計(jì)負(fù)荷下不會(huì)發(fā)生液泛現(xiàn)象。根據(jù)以上驗(yàn)算，可以認(rèn)為精餾塔徑及各工藝尺寸使合適的。（十二）塔板負(fù)荷性能圖1）霧膜夾帶線（1）依式5.7RO,u、

ev=(a)3；H-hTf式中Vu=saA—ATfs=0.68V81.53—60.0846s氣=2.5(h+h)=2.5h+2.84x10-3E(3600L、s)2/3l近似取E21.0,hw=0.0438m,lw=0.84m3600L、s)2/3-0?^h=2.50.0438+2.84x10-3(故=0.095+1.873L2/3帶極限艮4-3N取霧膜夾q=18ev為5m8T0.1kg液H1=0/kg氣m，并代入上式0.6878Vs得120.12280.315-1.873L2/3s在操作范圍內(nèi)，任取幾個(gè)Ls值，依上式算出相應(yīng)的Vs值列于下表:Lsm3/s0.0010.0020.0040.006Vsm3/s1.92361.85211.73881.6436依表中數(shù)據(jù)在Vs——Ls圖中作出霧膜夾帶線（1）。2）液泛線聯(lián)立下式得皿H+h)=h+h+h+hTwpwowd近似取E=1.0,lw=0.84,hw=0.0438由下式得

h=2.84x10-3E(360°七)2/3owlw3600L、=2.84x10-3()2/30.84故h=0.74932Ls2/3由式h=h+h+howpClbh=0.05h2&(=)0h=0.05h2&(=)0°l0V0s5

CA&v0匕=0.05__V=0.VS6230.840.07207760.0984sh=e(h+h)=0.65(0.04380L7H932l0wows及=0.028470.4L27058s已算出h=0.00198h=0.05623V2+0.02847+0.487058L2/3+0.00198故：=0.03045+0.05623V2+0.487058L2/3ssh=0.153(Ls)2=0.153(Ls)2由下式d'l*h0.84x0.0378=151.7572L2s將HT=0.41m，hw為0.0438m，Q=0.5代入上式得0.0438)0.5(0.+41=0.030450.0438)=0.030450.V5823s0L.24$7058+s0.L4380.74923s+151.7572Ls21.齡21.齡6-3s26928.862s作出液泛線如圖中（2）所示。V2=2.714-7sLsm3/s0.0010.0020.0040.006Vsm3/s1.57861.53461.45521.3753操作范圍內(nèi)取若干Ls值代入上式，列表如下，3）液相負(fù)荷上限線取液體在降液管中停留時(shí)間為4秒，由下式Ls,maxHt^Al.=°41X0.0846=0.008672m3/sT液相負(fù)荷上限線如圖中（3）所示，坐標(biāo)圖上為與氣流量Vs無(wú)關(guān)的垂直線。4）漏液線由hL=h+h=0.0438+0.74932L2/3，us，min代入下式A0u=4.4CJ(0.0056+0.13h—h)p/pVs,min0.05361=4.4x0.84,'(0.0056+0.13(0.0438+0.74923L2/3)-0.00198)760.0984s3.0712V=0.19812.3017+24.105L2/3

s,minsLsm3/s0.0010.0020.0040.006Vsm3/s0.31590.32460.33790.3487整理后得下式:在操作范圍內(nèi)取若十個(gè)Ls值代入，列入下表，漏液線為Vs——Ls圖中（3）線。5）液相負(fù)荷下限線取平堰，堰上液層高h(yuǎn)ow=0.006m，作為液相負(fù)荷下限條件，依下式，取E=1.0，則h=2'4E(MO/,min)2/3-1000l0.006=2.84x10-3(4285.7143L.可Lsmin=7.165X10-4ms/s由上式在VsLs圖上作出液相負(fù)荷下限線(5)。將上面五條線繪制如下圖：（十三）冷凝器和再沸器熱量衡算在化工原理課本上查取各種物質(zhì)的物性參數(shù)如下表:組分苯甲苯已苯丙苯丁苯氣化r94.1368.0880.077669.89Cp0.41630.40790.41880.4210.311頂yi0.14520.79810.0665底xi0.02540.55610.32860.0858其中r和Cp單位都為kcal/kg，30°C水的比熱為4.174Kj/kgk,0.9Mpa水蒸氣的汽化潛熱為2036.2kj/kg。由前面算得塔頂V=128.378Kmol/h,D=50.9022Kmol/h塔頂冷凝器熱負(fù)荷由以上數(shù)據(jù)及平均汽化潛熱公式r=Eyi*ri求得r=73.3270Kcal/kg。1cal=4.184j平均摩爾質(zhì)量M=Eyi*Mi=91.7998kg/kmol由Q=MXVXrX4.184=91.7998X128.378X73.3270X4.184=3615662kj/h由Q=m水XCp水/t假設(shè)水溫從30°C上升到100°C，代入數(shù)據(jù)得3615662=mX4.174X(100-30)m=12374.78kg/h塔頂換熱器熱負(fù)荷由Q=MXDXCp均/tX4.174Cp=Eyi*Cpi勺=0.4138kcal/kgQ=91.7998X50.9022X0.4138X(104-40)X4.184=525917.8kj/h假設(shè)水從30C上升到40C貝Um=525917.8/(4.174X10)=12599.85kg/h塔底在沸器熱負(fù)荷由前面算得塔底進(jìn)料量L=L+F=177.4758Kmol/h，出料量W=49.0979Kmol/h，氣化量V=128.378Kmol/h，塔底溫度為151CM=Exi*Mi=91.7998kg/kmolr=Eyi*ri=77.22632kcal/h由Q=VXMXrX4.184=128.378X91.7998X77.2263X4.184