年产85万吨焦化厂终冷洗苯工段工艺计算.doc

洗苯、脱苯工段工艺计算进本工段物料参数年产85万吨焦化厂，煤气产率：11.7%，全焦率：78.00%，一年按365天，一天24小时煤气中杂质组成（煤气的分子量为10.4）H2S 0.02 g/Nm3煤气NH3 0.03 g/Nm3煤气HCN 0.3 g/Nm3煤气苯 28.45 g/Nm3煤气萘 0.4 g/Nm3煤气焦油 微量 g/Nm3煤气1. 煤气质量产量 G煤气=8510711.7%78%36524=1.46104 kg/h煤气体积流量 V煤气=1.451070.45=3.24104 m3/h煤气密度 =0.45 kg/m32. 煤气中粗苯质量流量 G苯=3.2410428.4510-3=921.78 kg/h煤气中粗苯体积流量 V苯=921.783.667=251.37 Nm3/h粗苯的密度 萘3.667 kg/ Nm33. 煤气中萘质量流量 G萘=3.241040.410-3=12.96 kg/h煤气中萘体积流量 V苯=12。961.162=11.15 Nm3/h萘的密度 萘1.162 kg/ Nm34. 煤气中H2S质量流量 GH2S=3.241040.0210-3=0.65 kg/h煤气中H2S体积流量 VH2S=0.651.518=0.43 Nm3/hH2S密度H2S1.518 kg/ Nm35. 煤气中NH3质量流量 GNH3=3.241040.0310-3=0.97 kg/h煤气中NH3体积流量 VNH3=0.970.708=1.37 Nm3/hNH3的密度 NH3 0.708 kg/ Nm36. 煤气中HCN质量流量 GHCN=3.241040.310-3=9.72 kg/h煤气中HCN体积流量 VHCN=9.720.93=10.45 Nm3/hHCN的密度HCN0.93 kg/ Nm3故煤气组成为：组成g/Nm3煤气分子量kg/hNm3/h煤气10.41450032400H2S0.02340.650.43NH30.03170.971.37HCN0.3279.7210.45苯28.4582.2（平均）921.78251.37萘0.412812.9611.15焦油微量160总计15446.0832674.77终冷塔一、物料衡算终冷塔塔前煤气中水蒸气体积流量煤气露点40下，水的饱和蒸汽压P40=752.08 mmH2O煤气入终冷塔压力P人=1200 mmH2O（表压） V塔前水蒸气=V混合煤气P40P入+9830-P40=32674.77752.081200+9830-752.08=2390.95Nm3/h质量流量G塔前水蒸气=V塔前水蒸气1822.4=2390.951822.4=1921.30 kg/h出终冷塔一段的水蒸气体积流量35下水的饱和蒸汽压 P35=573.44mmH2O煤气压力（表压）1200mmH2OV一段水蒸气=V混合煤气P40P入+9830-P40=32674.77573.441200+9830-573.44=1791.89Nm3/h质量流量G一段水蒸气=V一段水蒸气1822.4=1791.891822.4=1439.91 kg/h出终冷塔二段的水蒸气体积流量25下水的饱和蒸汽压 P25=323.02mmH2O煤气压力（表压）1200mmH2OV塔后水蒸气=V混合煤气P25P出+10333-P25=32674.77323.021200+9830-323.02=985.77 Nm3/h 质量流量G塔后水蒸气=V塔后水蒸气1822.4=985.771822.4=792.14kg/h进入终冷塔荒煤气的物料组成：组成g/Nm3煤气kg/hNm3/h煤气1450032400苯28.45921.78251.37H2S0.020.650.43NH30.030.971.37HCN0.39.7210.45萘0.412.9611.15焦油微量水蒸气1921.302390.95总计17367.3835065.72出终冷塔一段荒煤气物料组成组成g/Nm3煤气kg/hNm3/h煤气1450032400苯28.45921.78251.37H2S0.020.650.43NH30.030.971.37HCN0.39.7210.45萘0.412.9611.15焦油微量水蒸气1439.911791.89总计16885.9934466。66出终冷塔二段荒煤气物料组成组成g/Nm3煤气kg/hNm3/h煤气1450032400苯28.45921.78251.37H2S0.020.650.43NH30.030.971.37HCN0.39.7210.45萘0.412.9611.15焦油微量水蒸气792.14985.77总计16238.2233660.54二、热量衡算1. 入终冷塔物料带入热量1) 粗气带入热量：粗气比热0.73kcal/(kg)Q11=146000.7355=586190kcal/h2) 水蒸气带入热量：40水蒸气的焓617.4 kcal/kgQ12=1921.30614.7+1921.30150.18=1186210.62kcal/h3) 粗苯带入热量：粗苯的比热0.26 kcal/(kg)Q13=921.780.2655=13181.45kcal/h4) 其他物料带入热量：取物料平均比热为0.24 kcal/(kg)Q14=0.65+0.97+9.72+12.96550.24=320.76kcal/h5) 循环水带入热量：Q15=32W循环水2. 出终冷塔一段物料带走热量1) 粗气带走热量：Q21=146000.7335=373030kcal/h2) 粗苯带走热量:Q22=921.780.2635=8388.20kcal/h3) 水蒸气带走热量: 35水蒸气的焓611.2 kcal/kgQ23=1439.91611.2+481.39135=896921.64kcal/h4) 其他物料带走热量Q24=0.65+0.97+9.72+12.96350.24=204.12kcal/h5) 循环水带走热量Q25=40W循环水3. 出终冷塔二段物料带走热量1) 粗气带走热量：Q31=146000.7325=266450kcal/h2) 粗苯带走热量:Q22=921.780.2625=5991.57kcal/h3) 水蒸气带走热量: 35水蒸气的焓607.8 kcal/kgQ23=792.14607.8+647.77125=497656.94kcal/h4) 其他物料带走热量Q24=0.65+0.97+9.72+12.96250.24=145.80kcal/h5) 循环水带走热量Q25=40W循环水4. 热量衡算终冷塔一段：586190+1186210.62+13182.45+320.76+32W循环=373030+8388.20+896921.64+204.12+40W循环373030+8388.20+896921.64+204.12+18W冷却=266450+5991.57+497656.94+145.80+40W冷却W循环=63419.98kg/hW冷却=101660.01kg/h三、传热面积1. 温度差煤气 55 35 25循环水40 32 ；冷却水23 18终冷塔一段温度差 40-32=8终冷塔二段温度差 23-18=52. 终冷塔基本参数的选取：选453管子，管长2000mm，管程走循环水和冷却水，流通面积0.04m2，壳程走煤气，流通面积1.31m2。3. 终冷塔一段传热系数K1平均温度 （32+40）/2=361K!=11+11+22+12式中1粗气到管壁的给热系数1管壁厚度，取1=0.003m2管壁垢层厚度1钢的导热系数，取1=40 kcal/mh2管壁到循环水的给热系数粗气到管壁的给热系数1lg1=1.69+0.0246x根据终冷塔一段进出口煤气中水蒸气体积含量，求的粗气中水蒸气平均含量x=2390.9535065.7+1791.8934466.660.5100=6.01%带入上式lg1=1.69+0.02466.01%=1.841=68.84 kcal/m2h管壁垢层热阻取 22=0.001m2h/kcal管壁至循环水的给热系数2按下式计算2=Nud式中 Nu怒塞尔特准数水的导热系数，取=0.538kcal/mhd管壁内径 d=0.039mNu准数按下式计算Nu=0.023Re0.8Pr0.4式中Re雷诺准数Pr普兰特准数矫正系数Re准数按下式计算Re=1000du式中u管程水流速水的密度，取=993.68kg/m3水的动力粘度，=0.7225cP管内流速u=63419.98993.6836000.04=0.44m/sRe=10000.0390.44993.680.7225=23600.76Pr准数按下式计算Pr=3.6c=3.60.9970.72250.538=4.82式中c水的比热，取c=0.997kcal/kg由此求得Nu=0.02323600.760.84.820.40.8935=121.452=121.450.5830.039=1815.52 kcal/m2h1K!=168.84+0.00340+0.001+11815.52K1=61.91kcal/m2h4. 终冷塔二段传热系数K21K2=11+11+22+12式中1粗气到管壁的给热系数11 管壁热阻，取11=0.000075 m2h/kcal 22 管壁垢层热阻，取22=0.001m2h/kcal 2 管壁到冷却水的给热系数1 按下式计算lg1=1.69+0.0246x根据终冷塔二段进出口煤气中水蒸气体积含量，求的粗气中水蒸气平均含量x=985.7733660.54+1791.8934466.660.5100=4.06%带入上式lg1=1.69+0.02464.06%=1.69%1=49.09 kcal/m2h管壁至循环水的给热系数2按下式计算2=Nud取=0.517kcal/mhc=0.999 kcal/kg=0.9905cPd=0.039mNu准数按下式计算Nu=0.023Re0.8Pr0.4管内流速u=101660.01998.236000.04=0.71m/sRe=1000du=10000.0390.71998.20.9905=27905.26Pr=3.6c=3.60.9990.99050.517=6.89由此求得Nu=0.02327905.260.86.890.40.8177=146.612=146.610.5170.039=1943.52 kcal/m2h1K2=149.09+0.00340+0.001+11943.52K2=45.54kcal/m2h5. 传热面积终冷塔一段 W循（40-32）=K1A1t1t1=15-3ln153=7.46A1=863419.987.4661.91=1098.54m2终冷塔二段W冷（23-18）=K2A2t2t2=12-7ln127=9.28A1=5101660.09.2845.54=1202.76m2总传热面积A=1098.54+1202.76=2301.3m2洗苯塔采用单台填料塔原始数据煤气入塔温度25，压力1200mmH2O,出塔压力900 mmH2O。入塔物料：组成g/Nm3煤气kg/hNm3/h煤气1450032400苯28.45921.78251.37H2S0.020.650.43NH30.030.971.37HCN0.39.7210.45萘0.412.9611.15焦油微量水蒸气792.14985.77总计16238.2233660.54出塔物料：组成g/Nm3煤气kg/hNm3/h煤气1450032400苯264.817.67H2S0.020.650.43NH30.030.971.37HCN0.39.7210.45萘0.412.9611.15焦油微量水蒸气792.14985.77总计15381.2433426.84物料衡算湿煤气实际流量入塔时V入=33660.54273+252731033310333+1200=32919.92m3/h出塔时V出=33426.84273+252731033310333+1200=33564.46m3/h塔内平均流量V=V入+V出2=32919.92+33564.462=33242.19m3/h湿煤气实际含苯量入塔时ai=921.7832919.921000=28.00g/m3出塔时a2=64.833564.461000=1.93 g/m3粗苯回收率=921.78-64.8921.78=92.97%贫富油实际含苯量及洗油量当塔顶吸收过程达到平衡时，贫油最高允许含苯量按下式计算0.0224yPMcb=1.25(x/Mcb)PcbxMcb+100-xMm煤气出塔时含苯量y=1.93 g/m3煤气出塔时压力P=10333+900=11233mmH2O=826.26mmHg粗苯平均分子量Mcb=82.2粗苯饱和蒸汽压Pcb=101mmHg洗油分子量Mm=160,0.02241.93826.2682.2=1.25(x/82.2)101x82.2+100-x160解得贫油含苯量x=0.177%则入塔贫油实际含苯量c1=xn=0.177%1.15=0.154%则与c1平衡的煤气出塔含苯量为0.0224y826.2682.2=1.25(0.154/82.2)1010.15482.2+100-0.15482.2y=1.678g/m3故塔顶吸收达到平衡时，粗苯的最高回收率为max=1-1.67828.00=94.01%最小洗油循环量为Lmin=PcbMmV22.4Pmax25时粗苯的饱和蒸汽压Pcb=101mmHg洗油分子量Mm=160入塔时煤气流量V=33660.54-251.37=33409.17m3/h粗苯回收率=94.01%粗苯入塔时压力P=1200+10333=11533mmH2O=848.33mmHg因此，Lmin=10116033409.1792.97%22.4848.3394.01%=28097.20kg/h实际洗油循环量L=mLmin=1.528097.20=42145.79 kg/h回收的粗苯量G1=921.78-64.8=856.98富油含苯量G2=c1+GL=0.154+856.9842145.79=2.18%贫油总含苯量42145.790.154%=64.90%富油总含苯量856.98+64.90=921.88洗苯塔的设备计算采用250Y塑料孔板波纹填料，比表面积250,孔隙率97%，密度7.5泛点气速logwF2ga3gll0.2=0.291-1.75LG0.25gl0.125WF泛点气速g重力加速度，取g=9.8m/s2a填料比表面积，取a=250m2/m3孔隙率，=0.97a/3干填料因子，a/3=250/0.973=274m-1g 气体密度l 液体密度, l=1055kg/m3l液体粘度，1=16.5cPL液体流量，L=42145.79kg/hG气体流量在标准状况下，入塔前密度G人=16238.22/33660.54=0.48kg/m3出塔后密度G出=15381.24/33426.84=0.46kg/m3平均密度=0.48+0.462=0.47kg/m3温度25，平均压力1050mmH2O,气体密度g=0.47273273+259830+105010333=0.44kg/m3故gl=0.441055=0.00042G=gVg=0.4433242.19=14626.56kg/hLG=42145.7914626.56=2.88则logwF29.82740.0004416.50.2=0.291-1.752.880.250.000420.125得WF=3.60m/s对填料塔，操作气速为泛点起诉的0.50.85当V=0.5WF,V