年产85万吨焦化厂终冷洗苯工段工艺计算

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）H2S0.02g/Nm3煤气NH30.03g/Nm3煤气HCN0.3g/Nm3煤气苯28.45g/Nm3煤气萘0.4g/Nm3煤气焦油微量g/Nm3煤气1.煤气质量产量G煤气=85×107×11.7%78%×365×24=1.46×104kg/h煤气体积流量V煤气=1.45×1070.45=3.24×104m3/h煤气密度ρ=0.45kg/m32.煤气中粗苯质量流量G苯=3.24×104×28.45×10−3=921.78kg/h煤气中粗苯体积流量V苯=921.783.667=251.37Nm3/h粗苯的密度ρ萘＝3.667kg/Nm33.煤气中萘质量流量G萘=3.24×104×0.4×10−3=12.96kg/h煤气中萘体积流量V苯=12。961.162=11.15Nm3/h萘的密度ρ萘＝1.162kg/Nm34.煤气中H2S质量流量GH2S=3.24×104×0.02×10−3=0.65kg/h煤气中H2S体积流量VH2S=0.651.518=0.43Nm3/hH2S密度ρH2S＝1.518kg/Nm35.煤气中NH3质量流量GH3=3.24×104×0.03×10−3=0.97kg/h煤气中NH3体积流量VH3=0.970.708=1.37Nm3/hNH3的密度ρNH3＝0.708kg/Nm36.煤气中HCN质量流量GHC=3.24×104×0.3×10−3=9.72kg/h煤气中HCN体积流量VHC=9.720.93=10.45Nm3/hHCN的密度ρHCN＝0.93kg/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=752.08mmH2O煤气入终冷塔压力P人=1200mmH2O（表压）V塔前水蒸气=V混合煤气×P40P入+9830−P40=32674.77×752.081200+9830−752.08=2390.95Nm3/h质量流量G塔前水蒸气=V塔前水蒸气×1822.4=2390.95×1822.4=1921.30kg/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=32674.77×573.441200+9830−573.44=1791.89Nm3/h质量流量G一段水蒸气=V一段水蒸气×1822.4=1791.89×1822.4=1439.91kg/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=32674.77×323.021200+9830−323.02=985.77Nm3/h质量流量G塔后水蒸气=V塔后水蒸气×1822.4=985.77×1822.4=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=14600×0.73×55=586190kcal/h2)水蒸气带入热量：40℃水蒸气的焓617.4kcal/kgQ12=1921.30×614.7+1921.30×15×0.18=1186210.62kcal/h3)粗苯带入热量：粗苯的比热0.26kcal/(kg·℃)Q13=921.78×0.26×55=13181.45kcal/h4)其他物料带入热量：取物料平均比热为0.24kcal/(kg·℃)Q14=(0.65+0.97+9.72+12.96)×55×0.24=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=14600×0.73×35=373030kcal/h2)粗苯带走热量:Q22=921.78×0.26×35=8388.20kcal/h3)水蒸气带走热量:35℃水蒸气的焓611.2kcal/kgQ23=1439.91×611.2+481.39×1×35=896921.64kcal/h4)其他物料带走热量Q24=(0.65+0.97+9.72+12.96)×35×0.24=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=14600×0.73×25=266450kcal/h2)粗苯带走热量:Q22=921.78×0.26×25=5991.57kcal/h3)水蒸气带走热量:35℃水蒸气的焓607.8kcal/kgQ23=792.14×607.8+647.77×1×25=497656.94kcal/h4)其他物料带走热量Q24=(0.65+0.97+9.72+12.96)×25×0.24=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=5℃2.终冷塔基本参数的选取：选φ453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=36℃1K!=1α1+δ1λ1+δ2λ2+1α2式中α1——粗气到管壁的给热系数δ1——管壁厚度，取δ1=0.003mδ2——管壁垢层厚度λ1——钢的导热系数，取λ1=40kcal/m·h·℃α2——管壁到循环水的给热系数粗气到管壁的给热系数α1lgα1=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+1791.8934466.66)×0.5×100=6.01%带入上式lgα1=1.69+0.0246×6.01%=1.84α1=68.84kcal/m2·h·℃管壁垢层热阻取δ2λ2=0.001m2·h·℃/kcal管壁至循环水的给热系数α2按下式计算α2=Nuλd式中Nu——怒塞尔特准数λ——水的导热系数，取λ=0.538kcal/m·h·℃d——管壁内径d=0.039mNu准数按下式计算Nu=0.023Re0.8Pr0.4ψ式中Re——雷诺准数Pr——普兰特准数ψ——矫正系数Re准数按下式计算Re=1000duρμ式中u——管程水流速ρ——水的密度，取ρ=993.68kg/m3μ——水的动力粘度，μ=0.7225cP管内流速u=63419.98993.68×3600×0.04=0.44m/sRe=1000×0.039×0.44×993.680.7225=23600.76Pr准数按下式计算Pr=3.6cμλ=3.6×0.997×0.72250.538=4.82式中c——水的比热，取c=0.997kcal/kg·℃由此求得Nu=0.023×23600.760.8×4.820.4×0.8935=121.45α2=121.45×0.5830.039=1815.52kcal/m2·h·℃1K!=168.84+0.00340+0.001+11815.52K1=61.91kcal/m2·h·℃4.终冷塔二段传热系数K21K2=1α1‘+δ1‘λ1‘+δ2’λ2’+1α2’式中α1‘——粗气到管壁的给热系数δ1‘λ1‘——管壁热阻，取δ1‘λ1‘=0.000075m2·h·℃/kcalδ2’λ2’——管壁垢层热阻，取δ2’λ2’=0.001m2·h·℃/kcalα2’——管壁到冷却水的给热系数α1’按下式计算lgα1’=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+1791.8934466.66)×0.5×100=4.06%带入上式lgα1’=1.69+0.0246×4.06%=1.69%α1’=49.09kcal/m2·h·℃管壁至循环水的给热系数α2按下式计算α2’=Nuλd取λ=0.517kcal/m·h·℃c=0.999kcal/kg·℃μ=0.9905cPd=0.039mNu准数按下式计算Nu=0.023Re0.8Pr0.4ψ管内流速u=101660.01998.2×3600×0.04=0.71m/sRe=1000duρμ=1000×0.039×0.71×998.20.9905=27905.26Pr=3.6cμλ=3.6×0.999×0.99050.517=6.89由此求得Nu=0.023×27905.260.8×6.890.4×0.8177=146.61α2=146.61×0.5170.039=1943.52kcal/m2·h·℃1K2=149.09+0.00340+0.001+11943.52K2=45.54kcal/m2·h·℃5.传热面积终冷塔一段W循（40-32）=K1A1Δt1Δt1=15−3ln153=7.46℃A1=8×63419.987.46×61.91=1098.54m2终冷塔二段W冷（23-18）=K2A2Δt2Δt2=12−7ln127=9.28℃A1=5×101660.09.28×45.54=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900mmH2O。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