化工原理乙醇水分离

0材料生产工艺设计实习设计实习题目：常压连续乙醇-水精馏设计班级：13材料1班姓名：郑阳、耿文文、陶园、陈孝鹏学号：2013507284/2013507285/2013507286/2013507287组号：第7组完成日期：2016年6月10日材料工程系2016.6.1012目录第一章设计任务书·······································4第二章任务要求·······································4第三章精馏塔设计物料计算···························53.1物料衡算··········································53.2回流比的确定········································53.2.1平均相对挥发度的计算······························53.2.2最小回流比的计算和适宜回流比的确定················63.3塔板数的确定········································73.3.1精馏塔的气液相负荷·································73.3.2精馏段与提馏段操作线方程···························73.3.3逐板法确定理论板数及进料位置·······················73.3.4全塔效率·········································93.4塔的工艺条件及物性数据计算···························93.4.1操作压强Pm······································93.4.2温度tm···········································93.4.3平均分子量M精···································103.4.4平均密度M······································113.4.5液体表面张力m································113.4.6液体粘度mL，····································1233.4.7精馏段气液负荷计算·······························12第四章精馏塔设计工艺计算·····························134.1塔径·············································134.2精馏塔的有效高度计算······························144.3溢流装置·········································144.3.1堰长lW·······································154.3.2出口堰高hW··································154.3.3降液管的宽度Wd与降液管的面积Af············154.3.4降液管底隙高度ho····························154.4塔板布置及浮阀数目排列···························16第五章塔附属设备设计································185.1冷凝器的选择·····································185.2再沸器的选择······································185.3传热器的计算·······································194化工原理课程设计任务书摘要：精馏是分离液体混合物（含可液化的气体混合物）最常用的一种单元操作，在化工、炼油、石油化工等工业中得到广泛应用。精馏过程在能量剂的驱动下（有时加质量剂），使气、液两相多次直接接触和分离，利用液相混合物中各组分挥发度的不同，使易挥发组分由液相向气相转移，难挥发组分由气相向液相转移，实现原料混合液中各组分的分离。该过程是同时进行传质、传热的过程。乙醇在工业、医药、民用等方面，都有很广泛的应用，是很重要的一种原料。在很多方面，要求乙醇有不同的纯度，有时要求纯度很高，甚至是无水乙醇，这是很有困难的，因为乙醇极具挥发性，也极具溶解性，所以，想要得到高纯度的乙醇很困难。要想把低纯度的乙醇水溶液提升到高纯度，要用连续精馏的方法，因为乙醇和水的挥发度相差不大。精馏是多数分离过程，即同时进行多次部分汽化和部分冷凝的过程，因此可使混合液得到几乎完全的分离。关键词：乙醇、水、精馏、分离第一章设计题目：乙醇－水连续精馏塔的设计第二章任务要求设计一连续筛板浮阀精馏塔以分乙醇和水具体工艺参数如下：原料加料量F’＝5700kg/hhkmol74.20484.27/5700F塔顶产品流率D=74.84kmol/h塔底产品流率W=129.9kmol/h进料组成xF（摩尔分数）＝0.355馏出液组成xD＝0.90釜液组成xw＝0.033单板压降=0.7kPa（自选）R/Rmin=1.52工艺操作条件：常压精馏，塔顶全凝器，塔底间接加热，泡点进料，泡点回流。第三章精馏塔的工艺计算3.1物料衡算3.1.1原料液及塔顶，塔底产品的摩尔分率乙醇的摩尔质量46.07/AMkgkmol水的摩尔质量18.02/BMkgkmol原料加料量F＝100kmol/h进料组成xF＝0.35馏出液组成xD＝0.90釜液组成xw＝0.033单板压降=0.7kPaMF=02.18）35.01（07.4635.027.84kmolkg02.18）9.01（07.469.0MD43.27kmolkgMw=02.18）033.01（07.46033.018.95kmolkg3.2回流比的确定3.2.1平均相对挥发度的计算查[1]由相平衡方程1(1)xyx得(1)(1)yxxy由常压下乙醇-水溶液的平衡数据x0.180.20.250.30.350.46y0.510.5250.5510.5750.5950.61x0.450.550.50.60.650.7y0.6350.6780.6780.6970.7250.755由道尔顿分压定律iypp及AAAiBBBPxPx得11ABABiABAByyyyxxxx将上表数据代入得：序号123453.68153.15692.72542.35012.1263序号6789101.91551.72281.54081.41961.3207则'10123103.04…则平衡线方程：3.043.041113.04112.04xxxyxxx3.2.2最小回流比的计算和适宜回流比的确定xe=xF＝0.35xD＝0.90xw＝0.033=3.04因为q=1所以Xe=xF＝0.35由相平衡方程1(1)xyx=0.62最小回流比Rmin=1.04操作回流比取最小回流比的1.6倍R=1.5minR=1.56ii73.3板数的确定3.3.1精馏塔的气液相负荷精馏段：L=RD=1.56×74.84=116.75kmol/hV=（R+1）D=（1.56+1）×74.84=191.59kmol/h提馏段：L=L+qF=116.75+204.74=321.48kmol/hV=V+(q－1)F=V=191.59kmol/h3.3.2精馏段与提馏段操作线方程精馏段操作线方程：35.061.0yx提馏段操作线方程：022.0'68.1'''''xxWLWxWLLyW3.3.3逐板法确定理论板数及进料位置对于乙醇—水属物系，可采用逐板计算法求理论板层数。根据求得的相对挥发度可知相平衡方程为1(1)nnnxyxnnnnnyyyy04.204.3)1(x因为泡点进料，q=1，35.0xFqx第一块板上升的蒸汽组成90.0yD1x第一块板下降的液体组成由式（c）求取7475.0x1由第二块板上升的气相组成用（a）式求取:8070.011R12RxxRyD5790.0x2由第二块板下降的液体组成如此反复计算：7044.0y3,4394.0x36193.0y4,3486.0x4Fx8因第5块板上升的气相组成由提馏段操作方程（b）:计算0.022-x678.1n1DFDnnxVFxDxxVLy如此反复计算：5629.0y5,2976.0x54774.0y6,2311.0x63658.0y7,1595.0x72456.0y8,0967.0x81403.0y9,0509.0x90634.0y10，0218.0x01wx=0.033根据以上求解结果得：总理论板数为10（包括再沸器）进料板位置为4精馏段理论板数3提馏段理论板数7表3.1乙醇/水温度-成平衡数据93.3.4全塔效率由进料组成35.0xF经查表1得泡点温度15.78Td℃2.81TF℃40.98TW℃在此温度下查文献得：=0.419mPas乙醇=0.315mPas水则板效率E由0.2450.49()rlEU计算则实际塔板数：15.24414.010N精馏段:825.73ENT精提馏段:1791.167ENT提总塔板数：N=253.4塔的工艺条件及物性数据计算以精馏段为例进行计算：3.4.1操作压强Pm塔顶压强kPa3.1053.1014PD，取每层塔板压降kPa7.0P进料板压强kPa2.1247.0273.105PF精馏段平均操作压强kPa75.11422.1243.105Pm3.4.2温度tm根据操作压强，依据安托因方程及泡点方程试差计算得：塔顶℃27.78tD，进料板℃67.84tF则精馏段平均温度10℃，精47.81267.8427.78tm3.4.3平均分子量M精求平均相对挥发度塔顶、进料板、塔底操作温度下纯组分的饱和蒸汽压P0表3-2塔顶24.227.4533.101PP0B0AD进料板20.268.5896.128F塔底20.233.10105.223W全塔平均相对挥发度为22.220.224.2WD相平衡方程x22.11x22.2x11xy）（（1）塔顶90.0yx1D7475.0x1kmolkg/265.4302.18)90.01(07.4690.0MVDkmolkg/265.3902.18）7574.01（07.467574.0MLD（2）进料板6193.0yF3486.0xF11kmolkg/391.3502.18）6193.01（07.466193.0MVFkmolkg/76.2702.18）3486.01（07.463486.0MLF精馏段的平均摩尔质量kmolkg/37.342391.35265.43M，精Vkmolkg/51.33276.27265.39M，精L3.4.4平均密度M（1）液相密度ML，BLBALAML1，，，塔顶：5.97210.078990.01M，L2.804M，Lkg/m3进料板上由进料板液相组成3486.0xA58.002.18）3486.01（07.463486.007.463486.0A2.92458.017.79658.01M，L7.845M，LFk