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Easy method HE calculation sizing costing


X-5F.10 SIZING AND COSTING FOR HEAT EXCHANGERHeat Exchanger, X-5Heat exchanger type2 shell and 4 tubesDesign typeSplit-ring floating headHeat exchanger orientationHorizontalTube inlet directionHorizontalNumber of parallel plate1Tube side stream feed1Tube sideNgShell sideSteamHeat duty (kW)11666.670a) Equipment sizingshelltubeStreamSteamNGTin (K)617.60330.86Tout (K)579.55607.25T1(oC) =344.10T2(oC) =306.40t1(oC) =57.71t2(oC) =334.10R =(T1-T2)/(t2-t1)( eqn. 12.6 )=0.138S=(t2-t1)/(T1-t1)( eqn. 12.7 )=0.964Ft can be obtained from fig 12.19 ( vol. 6 ),Ft =0.8900DTlm can be calculated from the equation,( eqn. 12.4 )DTlm =74.9681Therefore, the actual temperature difference isFtDTlm =66.7216Assumption: (Table 12.1, 'Chem. Eng', Vol. 6)U454.264W/(C.m2)Provisional area of heat exchanger, A can be obtained trough the formulae,Provisional area, A384.9216m24143.2620ft2b) Tube rating ( App.5.-2, Tranport Processes )MaterialCarbon steelBWG number18Length of tube Lt (m)2.44Outer diameter, Dto (mm)19.05Inner diameter, Dti (mm)16.56Material Thermal Conductivity ( W/m.K )16.3Heat transfer area of a tube, AtArea of one tube, At (m2)0.1460(ft2)1.5718Number of tube, NtNumber of tube, Nt2636Tube pitch is the distance between tube centres and formulated asTube pitch, Pt (mm)23.8125From Table 12.4, Chemical Engineering , Vol. 6 ( 1st Edition )Triangular pitch K10.249( 2 passes ) n2.207The bundle diameter, Db( eqn. 12.3b )Bundle diameter, Db (mm)1269.1683From Chemical Engineering , Vol. 6 (figure 12.10)Shell bundle clearance (mm)72For Split-ring floating head,Ds = Db + shell bundle clearanceShell internal diameter, Ds (m)1.3412c) Tube side coefficientMean temperature (K)Tmean =(Tc.in +Tc,out)/2Mean temperature (K)469.0550Tube cross-sectional area, AtTube cross-sectional area, AtTube cross-sectional area, At215.4105mm2Tube per pass = Nt659Total flow area (m2), ATTotal flow area (m2), AT0.1420Mass flow rate (inside tube), m10.1183kg/sFluid velocity, nfmass velocity, nf71.2794kg/m2.sPhysical properties of the tube side fluidPhysical properties of Waterwater density, rt1015.2654kg/m3MW18.0305kg/kmoleViscosity of water, mtL7.94E-04Ns/m217.9948kcal/kmol/cHeat capacity, Ctp4.1717236904kJ/kg.K0.081644kcal/m/hr/cThermal conductivity, ktf0.0948882897W/m.KLinear velocity, uReynold number, RePrandtl number, Prlinear velocity, u (m/s)0.0702Reynold number, Re1486.072Prandtl number, Pr34.9211L/Dti147.3430From figure 12.23, Chemical Engineering, Vol. 6Heat transfer factor, jh0.0035Tube side heat transfer coefficient, hi( eqn. 12.15 )Tube side heat transfer coefficient, hi96.267379973W/m2.C( assuming viscosity of the fluid is identical at the wall and of the bulk fluid )d) Tube side pressure dropFrom figure 12.24 'Chemical Engineering'. Vol. 6friction factor, jf0.0030Tube side pressure drop, DPt( eqn. 12.20 )where m = 0.25 for laminar flow, Re2100Np = number of tube side passesTube side pressure drop,0.0302kPa(acceptable)DPte) Shell side coefficientShell diameter, Ds1.3412mBafflediameterBaffle spacing, lB1.2071mBaffle Diameter1.3396mTube pitch, Pt23.8125mmCross flow area, As( eqn. 12.21 )Cross flow area, As0.3238m2Shell side mass velocity, GsMass flow (inside shell), Ws204583kg/hrShell side mass velocity, Gs175.5206kg/s.m2Shell side equivalent diameter, De( eqn. 12.23 )Shell side equivalent diameter, De13.5265mmMean temperature (C)Tmean = (Tshell.in +Tshell.out)/2Mean temperature (C)598.5750Physical properties of shell fluid (light hydrocarbon)Physical propertiesFluid density, rs3.9318kg/m3Viscosity, msL3.3589E-05Ns/m2MW15.9561kg/kmoleHeat capacity, Csp2.6068251014kJ/kg.K9.9509kcal/kmol/cThermal conductivity, ksf0.1718W/m.K0.147848kcal/m/hr/cReynold number, Re( eqn. 12.24 )Reynold number, Re2989.010Prandtl number, Pr0.5096Selecting 15% for baffle cutFrom figure 12.29, Chemical Engineering, Vol. 6Heat Transfer Factor, jh0.0100Shell side heat transfer coefficient, hs( eqn. 12.25 )Shell side heat transfer coefficient, hs303.9659560232W/m2.Cf) Shell side pressure dropLinear velocity, usLinear velocity, us44.6413m/sFrom figure 12.30 'Chemical Engineering'. Vol. 6friction factor, jf0.0800Shell side presure drop, DPs( eqn. 12.26 )Shell side presure drop,26979084.0816Pa(acceptable)DPs26979.0841kPag) Overall CoefficientOutside fluid film coefficient, hs, W/m2.oC303.9659560232Inside fluid film coefficient, hi, W/m2.oC96.267379973Outside dirt coefficient (fouling factor), hod, W/m2.oC5000Inside dirt coefficient, hid, W/m2.oC (from Table 12.2, vol. Six )5500Thermal conductivity of the tube wall material, kw, W/m.oC16.3Tube inside diameter, Dti, m0.01656Tube outside diameter, Dto, m0.01905Overall heat transfer coefficient can be calculated by using the formula( eqn. 12.1 )Therefore,1/Uo =0.0157305122Uo =63.5707208245W/m2.Ch) Number of baffle, NbNumber of baffle, NbNbaffle1CostingTypeShell and tubeArea (m2)384.9216MaterialCarbon SteelFeed Pressure5.07barWith reference to costing method proposed by L.T. Biegler,Base Cost, CBare Module Cost, BMCFor 100