年产5万吨苯酐物料衡算备考复习

1、物料衡算一、反应器的物料衡算通过 Aspen模拟得到邻二甲苯的进料量是6053.00kg/h，则空气的进气量为6053.00 X 9.5 =57503.5kg/h，根据苏南地区的平均空气组成可得：02=57503.5 X 20.573%=11830.20kg/hN2=57503.5 X 76.434%=43952.22kg/hCO2=57503.5X 0.03%=17.25kg/hH2O=57503.5X 2.05%=1178.82kg/h惰性气体=57503.5 X 0.913%=525.01kg/h主反应以及副反应的选择性如下:反应产物苯酐顺酐苯甲酸苯酞柠槺酐COCO2选择性%78.948

2、.154.722.051.441.303.40对主反应:C8H10+3OP C8H4O3 （苯酐）+3H2O1069614854式中各物质的质量为：C8H10: 6053.00 X 99.8%X 78.94%=4768.68kg/hO2: 4768.68/106 X 96=4318.80 kg/hC8H4O3 （苯酐）:4768.68/106 X 148=6658.16 kg/hH2O: 4768.68/106 X 54=2429.33 kg/h对副反应：（1）C8H10+7.5O2t C4H2O3 （顺酐）+4CO2+4H2O1062409817672式中各物质的质量为：C8H10: 605

3、3.00 X 99.8%X 8.15%=492.33kg/hO2: 92.33/106 X 240=1114.71 kg/hC4H2O3 （顺酐）：492.33/106 X 98=455.17 kg/hCO2: 492.33/106 X 176=817.45 kg/hH2O: 492.33/106 X 72=334.41 kg/h（2）C8H10+3O2t C7H6O2 （苯甲酸）+CO2+2H2O106961224436式中各物质的质量为：C8H10: 6053.00 X 99.8%X 4.72%=283.92kg/hO2: 283.92/106 X 96=257.14 kg/hC7H6O2

4、 （苯甲酸）：283.92/106 X 122=326.78 kg/hCO2: 283.92/106 X 44=117.85 kg/hH2O: 283.92/106 X 36=96.42kg/h（3）C8H10+2O2t C8H6O2 （苯酞）+ 2H2O1066413436式中各物质的质量为：C8H10: 6053.00 X 99.8%X 2.05%=123.84kg/h02: 123.84/106 X 64=74.77kg/hC8H6O2 （苯酞）：123.84/106 X 134=156.55kg/hH2O: 123.84/106 X 36=42.06kg/h（4）C8H10+4.5O2

5、t C5H4O3 （柠槺酐）+ 3CO+3H2O1061441138454式中各物质的质量为：C8H10: 6053.00 X 99.8%X 1.44%=86.99kg/hO2: 86.99/106 X 144=118.18kg/hC5H4O3 （柠槺酐）:86.99/106 X 113=92.73kg/hCO: 86.99/106 X 84=68.94kg/hH2O: 86.99/106 X 54=44.32kg/h（5）C8H10+6.5O2t 8CO+5H2O10620822490式中各物质的质量为：C8H10: 6053.00 X 99.8%X 1.30%=78.53kg/hO2: 7

6、8.53/106 X 208=154.10kg/hCO: 78.53/106 X 224=165.95kg/hH2O: 78.53/106 X 90=66.68kg/h（6）C8H10+10.5O2t 8CO2+5H2O10633635290式中各物质的质量为：C8H10: 6053.00 X 99.8%X 3.40%=205.39kg/hO2: 205.39/106 X 336=651.05kg/hCO2: 205.39/106 X 352=682.05kg/hH2O: 205.39/106 X 90=174.39kg/h综合以上数据，可以得出反应器出口气体组成为：N2=43952.22kg

7、/h惰性气体=525.01kg/hO2=11830.20-4318.80-1114.71-257.14-74.77-118.18-154.10-651.05=5141.45 kg/hCO2=17.25+817.45+117.85+682.05=1634.60 kg/hH2O=1178.82+2429.33 +334.41+96.42+42.06+44.32+66.68+174.39=4366.43 kg/hC8H4O3 （苯酐）=6658.16 kg/hC4H2O3 （顺酐）=455.17 kg/hC7H6O2 （苯甲酸）=326.78 kg/hC8H6O2 （苯酞）=156.55kg/hC5

8、H4O3 （柠槺酐）=92.73kg/hCO=68.94+165.95=234.89 kg/hC8H10 （邻二甲苯）=6053.00 X（ 1-99.8%） =12.11 kg/h组分质量流量(kg/h)反应器进口摩尔分 数(%)质量流量(kg/h)反应器出口摩尔分 数(%)质量分 数(%)摩尔流量(kmol/h )质量分 数(%)摩尔流量(kmol/h )N243952.2269.161569.7276.29143952.2269.161569.7275.248惰性气体525.010.8313.140.639525.010.8313.140.6300211830.2018.61369.69

9、17.9685141.458.09160.677.702C0217.250.030.390.0191634.602.5737.151.781H201178.821.8565.493.1834366.436.87242.5811.629邻二甲苯6053.009.5257.102.77512.110.020.110.005苯酐00006658.1610.4844.992.157顺酐0000455.170.724.640.222苯甲酸0000326.780.512.680.128苯酞0000156.550.251.170.056柠槺酐000092.730.140.820.039C00000234.8

10、90.378.390.402合计63566.52057.5363556.102086.06、后冷器的物料衡算后冷器进口（ kg/h）后冷器出口（kg/h)组分苯酐工艺废气苯酐产品N243952.2243952.220惰性气体525.01525.010025141.455141.450CO21634.601634.600H204366.434366.430邻二甲苯12.118.763.35苯酐6658.163458.113200.05顺酐455.17423.7831.39苯甲酸326.78279.3547.43苯酞156.5543.06113.49柠槺酐92.7353.9638.77C0234.

11、89234.890合计63556.1060121.623434.48三、切换冷凝器的物料衡算切换冷凝器进口 （ kg/h）切换冷凝器出口(kg/h)组分冷气体固体苯酐N243952.2243952.220惰性气体525.01525.010025141.455141.450C021634.601634.600H204366.434366.430邻二甲苯8.768.760苯酐3458.11193.653264.46顺酐423.78141.12282.66苯甲酸279.351.68277.67苯酞43.060.2642.80柠槺酐53.9617.9735.99CO234.89234.890合计601

12、21.6256218.043903.58能量衡算一、对空气预热器(E101 )能量衡算由物料衡算知，空气的进料量为 57502.11kg/h，查工具书知，空气在298.15K(25C)478.15K(205C) 的平均比热容为 1.099kJ/kg/K，故有：Q=CmAT=1.099X 57502.11 x( 205-25) =1.138 X 107kJ又因为在6000Kpa时，水蒸气的汽化潜热为1892.4kJ/kg,所以需要中压蒸汽的质量为：m=1.138 X 107/1892.4=6010.93kg二、 对邻二甲苯蒸发器(E102)能量衡算由物料衡算知，邻二甲苯的进料量为6052.853

13、6kg/h，查工具书知，邻二甲苯在 298.15K (25C)478.15K (205C)的平均比热容为 4.161kJ/kg/K，故有：6Q=CmT=4.161 X 6052.8536 X( 205-25) =4.533 X 10 kJ又因为在6000Kpa时，水蒸气的汽化潜热为1892.4kJ/kg,所以需要中压蒸汽的质量为：m=4.533 X 106/1892.4=2395.61kg三、对反应器(R101 )能量衡算Q1 t起始物料带入设备中的能量，kJQ2 t冷却剂与设备间传递的能量，kJQ3t化学变化产生的能量，kJQ4 t生成物本身的能量，kJQ5 t反应系统的能量损失，kJ物料进

14、入设备时温度为478.15K (205C),则以478.15K (205C)为计算基准，即 Q仁0,查工具书得到下列各物质在 298.15K ( 25C)t 478.15K的平均比热容如下：组分比热容(kJ/kg/K)N21.06O21.15CO21.45H2O4.18惰性气体1.06邻二甲苯6.96苯酐5.23顺酐4.52苯甲酸5.18苯酞4.91柠槺酐4.52CO1.11所以：Q4= ( 43952.22 X 1.06+5141.45 X 1.15+1634.60 X 1.45+4366.43 X 4.18+525.01 X 1.06+12.11 X 6.96+6658.16 X 5.23

15、+455.17 X 4.52+326.78 X 5.18+156.55 X 4.91+92.73 X 4.52+234.89 X 1.11) X ( 205-25) =.65Q3=6052.8536 X 0.998 X 1000/106 X (0.7894 X 1302.2+0.0815 X 3177.9+0.0472 X 1339.8+0.0205 X834.7+0.0144 X 1674.8+0.013 X 2177.2+0.034 X 4576.4)= .37kJQ1=0Q5=5%*(Q1+Q3)=5%*.82= 4489008.59kJQ2=Q1+Q3-Q4-Q5=8972.42-44

16、89008.59= .7kJ四、对盐冷器(E103)冷盐溶液能量衡算盐溶液的组成为质量分数为40%的NaNO2、53%的KNO3、7%的NaNO3,则盐溶液的相对分子质量为 69X 40%+101X 53%+85X 7%=87g/mol查工具书得到：基团 a b c d-1NO349.76683.928-0.478-0.7040+1Na14.1869.6650.5294.815-1NO218.307126.3380.596-4.044+1K25.309-2.2840.2185.174根据公式:3626 2Cp=Aa+AbX 10 + cX 10 T + dX 10 T求得在 643.15K (

17、370C) 658.15K (385C)盐溶液的平均 Cp值为 125.35J/mol/K。故有：Q2=n X CpXA T即：.7=m/87 X 125.35 X (385-370)所以：m=3048028.988kg/h五、对后冷器（E105 ）能量衡算 对于反应后气体t贫反应气：组分质量流量（kg/h）摩尔流量（kmol/h）Cv,m(J/mol/K)Q(kJ)N244411.251621.0521.58001052413777.046O25532.674172.902522.268446.2968CO21199.83827.2629834.64640.00065CO503.033517

18、.9588121.26517.40024H2O3191.09177.132426.328458.9067苯酐6661.87144.97679176.8649538548882.4339顺酐455.89514.649235102.987203133038.00794苯甲酸329.11792.694961160.366644929820.5479苯酞156.66991.168006178.369667914375.24212柠槺酐91.960470.8204533102.16806265783.864566邻二甲苯00177.04643160合计62533.399872070.6161353733

19、739.747对于反应后气体t液相苯酐:组分质量流量（kg/h）摩尔流量（kmol/h）Cv,m(J/mol/K)Q(kJ)苯酐3202.0521.176.8649538264032.4279顺酐32.390.4102.98720312348.644185苯甲酸48.430.3160.36664494392.560706苯酞114.490.5178.369667910515.57079柠槺酐39.770.3102.16806262481.083591邻二甲苯4.350.0177.0464316501.3253439合计3441.4823.284271.6126已知 Q=3733739.747+

20、284271.6126=4018011.36kJ，锅炉供水的流量为40000kg/h，进口温度 t1 为298.15K(25 C )，求出 口温度 t2，根据 Q=nX Cp,mX (t2-t1)，其中 Cp,m 为 t1-t2 的平均值，即有：4018011.36 kJ =40000X (1/18) X 0.5 X (33.3+Cp,m-t2) X (t2-298.15)整理得：2.022 X 10A(-6) X t2A3-0.01609 X t2A2-58.33 X t2+22233.76839=0解得：t2=349.15K=76 C六、对气体冷却器(E104)能量衡算组分质量流量(kg/

21、h)摩尔流量(kmol/h)Cv,m(J/mol/K)Q(kJ)N245411.251621.83035722.5938480.544O25532.674172.896062523.660298.6262CO21199.83827.37.168960.1911CO503.033517.22.65671.6779H2O3191.09177.282777828.828421.1274苯酐6661.87145.01264189215.44139251600101.731顺酐455.89514.6127.84815298133.49078苯甲酸329.11792.5191.59723985283.47

22、012苯酞156.66991.8218.716887842193.64354柠槺酐91.96040.125.133376216802.71708邻二甲苯00212.66036310合计63533.39982071.5890339504347.219已知 Q=9504347.219kJ,锅炉供水的流量为40000kg/h，进口温度t1 为 348.15K(76C )，求出 口温度t2，根据 Q=nX Cp,mX(t2-t1)，其中 Cp,m为t1-t2的平均值，即有：9708548.627=40000 X (1/18) X 0.5X (33.999+Cp,m-t2) X (t2-351.25)整

23、理得：2.022 X 10A(-6) X t2A3-0.015864 X 上2人2-58.2243 X t2+30726.4886仁0解得：t2=47.15K=201 C七、对盐冷器(E103)锅炉供水能量衡算已知Q2=.7kJ,锅炉供水的流量为 40000kg,进口温度t1为473.15K(200 C )，求出口温度t2,根据Q=n X Cp,m,1 X (t-t1)+n X Cp,m,2 X (t2-t)+m X 汽化潜热,其中 t=548.55K(即 275.4 C -6000kP 的沸点),Cp,m,1为t1-t的平均值,Cp,m,2为t-t2的平均值，即有：.81=40000 X (

24、1/18) X 0.5 X (35.5632+36.50) X (275.4-201)+40000 X (1/18) X 0.5 X(36.50+Cp,m-t2)*(t2-548.552)+40000 X 1556.3整理得：2.022 X 10A(-6) X t2A3-0.015599 X t2A2-57.7115 X t2+38247.73253=0 解得：t2=580.15 K=307C八、对切换冷凝器(E106&E107 )能量衡算对于贫反应气t冷气体：组分质量流量(kg/h)摩尔流量(kmol/h)Cv,m(J/mol/K)Q(kJ)苯酐3853.42726.03666892

25、153.0029649262923.3776顺酐443.05264.888.26342.83399苯甲酸290.23552.8138.799927721793.34413苯酞96.137070.1153.59358137272.824136柠槺酐88.095620.388.3873.504729邻二甲苯00153.33449930N245411.221621.82928621.2270594.315O25532.666172.895812522.252388.5933CO21199.82927.32.58131.01806CO503.033217.20.24835.99216H2O3189.595177.199722226.00812114304169.7016合计60607.290992051.475543232325.505对于贫反应气t固体苯酐：组分质量流量(kg/h)摩尔流量(kmol/h)Cv,m(J/mol/K)Q(kJ)苯酐3264.4622.06153.00296492