化工原理课程设计再沸器的设计

1操作条件壳程管程温度/℃151.7（冷凝温度T）137.8(沸点tb)压力（绝）/MPa0.50.12蒸发量/(kg)10864.61壳程凝液物性（151.7℃）管程流体物性（137.8℃）液相气相潜热rc=2113.2kJ/kgrb=310.3kJ/kg热导率λc=0.684W/(m·K)λb=0.104W/(m·K)黏度μc=0.186/mPa·sμb=0.22/mPa·sμv=0.0085/mPa·s密度ρc=917kg/m3ρb=977.5kg/m3ρv=3.955kg/m3比热容Cpb=1.6748kJ/(kg·K)表面张力σb=19.6mN/m蒸汽压曲线斜率(△t/△p)s=2.159×10-3K·m2/kg再沸器的设计一、设计条件以在五个大气压下（0.5Mpa）的饱和水蒸汽作为热源。设计条件如下：（1）管程压力、、管程压力(以塔底压力计算)：MPaKPaPw12.0120217.03.105（2）将釜液视为纯氯苯，在釜底压力下，其沸点：根据安托因公式：tBCAplog查资料得：A=9.25B=225.69C=1516.04则有：69.22504.1516)1012.0log(b6tbt=137.8℃（3）再沸器的蒸发量由于该塔满足恒摩尔流假设，则再沸器的蒸发量：hkgVMDb/61.1086461.11242.2822（4）氯苯的汽化潜热常压沸点下的汽化潜热为35.3×103KJ/Kmol（即为313.5KJ/kg）.纯组分的汽化潜热与温度的关系可用下式表示：38.01238.012ttttrrcc(tc=359.2℃)其中8.1372btt℃,8.1311t℃,KJ/kg5.3131r,则：KJ/kg3.3105.3138.1312.3598.1372.35938.038.02r二、工艺结构尺寸的估算（1）、计算传热速率QW103647.93600/10003.31061.108645bbrDQ(2)、计算传热温差△tm△tm=T-tb=151.7-137.8=13.9℃(3)、假定传热系数K依据壳程及管程中介质的种类，按竖直管式查表，从中选取K=800W/（m2.k）(4)、计算传热面积Ap25pm84=9.13800103647.9tmKQA（5）、传热管规格选为Φ25mm×2mm,L=4000mm,按正三角形排列，则传热管的根数为（根）2684025.014.384LdANoT（6）、壳体直径3按3.4.3.2节中介绍的方法求取壳体直径。由2681)1(3aaNT解得9a(另外一负值舍去)则1912ab。于是：mmdbtDo648253)119(323)1(取进口管直径mmDi250，出口管直径mmDo600三、传热系数校核1.显热段传热系数KL①假设传热管出口气化率为13.0ex,釜液蒸发量为Db,则循环量Wt为)/(3010.0360061.10864skgxDWebt②显然段传热管内传热膜系数设传热管内流通截面积为IS,则传热管内釜液的质量流率G为222i928.0268021.0785.0)4(mNdSTi)m/(05.3250928.0302skgSWGIt310271022.005.325021.03bediGR543.3104.01022.0106748.133bbpbrCP显热段传热管内传热膜系数i为K)W/(m75.740023.024.08.0ireibPRd③壳程冷凝传热膜系数oK)W/(m5.7747)(87.123/13/1232oecccoRg4④污垢热阻沸腾侧：K/Wm10299.425iR冷凝侧：K/Wm1072.125OR管壁：K/Wm10299.426wR⑤显热段的传热系数)]/([44.3767.1136911072.1023.0025.010229.4021.0025.010299.4021.0477025.011125650000KmWRddRddRddKomwiiiiL2.蒸发段传热系数KE(1)管内沸腾-对流传热膜系数vtpbvba①泡核沸腾的平均修正系数a2aaaEh)kg/(m1017.105.3253600360026GGh08807.0)0085.022.0()5.977955.3()()(1.05.01.05.0vbbV当10.0exx时572.108807.0)13.0113.0()1(19.09.0021.0txxXxt查图得aE=0。当04.04.0exx时65.008807.0)04.0104.0()1(19.09.00084.0txxXxt查图得a＇=0.43。5215.0243.002'aaaE②泡核沸腾传热膜系数bK)W/(m1631096.1021.0102.11955.35.9771022.0103.310329021.010365.9543.3021.0104.0225.0)()1)(225.0231.02-533.069.03-3569.031.033.069.069.0b）（）—（）（（iVbbbiribPdArQdPd③质量分数x=0.4xe处的对流传热膜系数tp82.265.05.3)1(5.35.05.0ttXK)W/(m3.2023543.304.0131027021.0104.082.2023.0)1(023.024.08.04.08.0btp）（reiPxRd④管内沸腾-对流传热膜系数vK)W/(m4.20583.2023116323.02tpbvba（2）蒸发段传热系数EKK)W/(m1281)5.774711072.1232510299.4212510299.4214.205825()1(2156510oomowioiivERddRddRddK3.显热段和蒸发段长度显热段长度LBC和传热管总长L之比为4398.0305.9778.16749.1344.3761047021.014.310159.210159.2pt)(33tbpbmLTisBCWCtKNdptLL)m(7592.144398.0BCL(m)2408.27592.14CDL4.平均传热系数cKK)W/(m96042408.210427592.144.3762LLKLKKCDEBCLc65.面积裕度核算比较K计算和K假定，若K计算比K假定高出20%，则说明假定值尚可，否则要重新假定K值。%11.20800800960KKKc四、循环流量的校核1.循环推动力Dp当6363.0)033.0033.01(08807.0)1(033.0319.09.0ttxxXxxe时，279.0)16363.0216363.0(6363.0)121(5.025.02ttttttLXXXR3/9.275279.05.977)279.01(955.3)1(mkgRRLbLvtp当时exx，按上述同样的方法求得3tp/165mkg查表并根据焊接需要选取再沸器上部管板至接管入塔口间的高度ml9.0计算循环推动力DpPalpLgptptpbCDD133971659.0)8.2455.977(2408.281.9)(2.循环阻力fp54321ppppppf（1）管程进口管阻力1ps)kg/(m1.61525.0785.030785.0222itDWG531099.61022.01.61525.0biGDeRi0168.07543.001227.038.0eiRi729.3m)1914.00254.025.0(3426.0)0254.025.0()1914.00254.0(3426.0)0254.0(22iiiDDLPa7249221biiiGDLp(2)加速损失2p85.61)1()1(22LevbLeRxRxMs)kg/(m05.325422TitNdWGPa7405.977/14.953.187/222bMGP(3)传热管显热段阻力损失3p按直管阻力损失计算0271.031027/7543.001227.07543.001227.038.038.0eRPa122223biBCGdLP(4)传热管蒸发段阻力损失4p该段为两相流，故其流动阻力损失计算应按两相流考虑。计算方法是分别计算该段的气液两相流动的阻力，然后按一定方法加和，求得阻力损失。①气相流动阻力损失4vp取该段内的平均气化率067.032exx，则气相质量流速Gv为s)kg/(m05.325067.02xGGV气相流动的eVR:53536VVieVGdR0243.07543.001227.038.0VeVR8Pa153224VViCDVVGdLP②液相流动损失4Lps)kg/(m38.3032VLGGG289591022.038.303021.03-bLieLGdR0275.07543.001227.038.0LeLRPa138224bLiCDLLGdLP③两相压降4pPa2333)(44144144LVppp（5）管程出口阻力5p①气相流动阻力损失5vp出口管中气相质量流率为：s)kg/(m67.216.0785.03010.022GxGeV出口管中气相流动的eVR为：631052.1100085.067.216.0VVoeVGDR0152.07543.001227.038.0eVVRmDiDil51.69)1914.00254.0/6.0(3426.0)0254.0/6.0()1914.00254.0/(3426.0)0254.0/(22Pa2222'25VVoVVGDlP②液相流动阻力5Lp液相流率LG为：s)kg/(m2.20926.316.0785.06822VLGGG9液相c动eLR为：53107.51022.02.2096.0bLoeLGDR02748.07543.001227.038.0eLLRPa1112'25bLoLLGDlP③两相压降5pPa2549)(44154155LVppp循环阻力fpPa12638p54321pppppf3.循环推动力DP与循环阻力fP的相对误差049.0133971273813397DfDPPP核算满足要求，所设计的再沸器合适。五、传热面积裕度所需换热面积25m1.709.13776103647.9mctKQA面积裕度%11.20254254329AAAHp