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CONDENSATE AND STEAM TRAP IN STEAM LINE INSULATION IN PIPINGFLASH STEAM1Condensate load Condensate formed during warming

Where, Ci = Initial warm-up condensate load, kg/hr.W = Total weight of pipe including flanges and fittings = w x l + WfW = Weight per m. of pipe, kg/m. l = Length of pipe in m., i.e. distance between steam trap( for steam trap location calculation it can be taken as 50 or 60 m.) Wf = Weight of flanges, fittings etc T = Final temperature of pipe, i.e. steam temperature t = Initial temperature of pipe, i.e. ambient temperature S = Specific heat of steel , = 0.12 Kcal/kg C L = Latent heat of evaporation = hfg + (h1-h2), Kcal/kg hfg= Latent heat of evaporation h1 = Enthalpy of steam at final temperature h2= Enthalpy of steam at saturation temperature m= Warm-up time (Usually 0.6 C rise per second) =

Radiation condensate load

Kg/hr.Where, Q = Heat loss through insulation, Kcal/hr./m l & L has been defined earlier. Total Condensate Load, C = Ci + CrA safety factor ( usually 1.2 to 2 for TD type and 2 to 3 for inverted bucket type ) is multiplied with total condensate load for sizing steam trap.2General Thumb rule Steam tracing line : Approx. 30 kg/hr. for each 30m. of tracer. Heating water with steam :Kg/hr. condensate=Litre/hr. of water x Tempr. Rise, C500 Heating fuel oil with steam :

Kg/hr. condensate=Litre/hr. of fuel oil x Tempr. Rise, C1000 Heating air with steam :Kg/hr. condensate=Nm3/min of air x Tempr. Rise, C273Condensate load contdDischarge capacities of steam trapsThermodynamic Steam trapInlet Steam Pressure,Kg/cm2,gDischarge in Kg/hr.15 NB20NB0.72104551.082354901.412605201.762755803.523556905.274107957.0347086010.5558099514.06665109017.58725113521.09725113524.61810124528.12850131531.64895133535.15930136042.189851380Inverted bucket type Steam trapDifferential pressure, Kg/cm2Discharge in Kg/hr.15 NB20NB0.351953780.72554451.062904801.413154001.762404302.112654552.822953503.522653804.222804104.923004305.623153657.032903908.7931043010.5526036511.25265375The differential pressure is the difference between the pressure upstream and downstream of the trap. Where a trap discharges to atmosphere, the differential pressure is the same as upstream pressure.4TRAP TYPE AND SIZES FOR STEAM SERVICECondensate load contdPipe SizeTrapSl.No.DN (mm)TypeSize DN (mm)1.15Thermodynamic152.20- d o -153.25- d o -154.40- d o -155.50- d o -156.65- d o -207.80- d o -208.100- d o -209.125- d o -2010.150- d o -2011.200- d o -2012.250Inverted Bucket2513.300- d o -2514.350- d o -2515.400- d o -25Note:the above table is based on maximum trap spacing of 60 M.5INSULATION THICKNESS CALCULATION Design Code : IS 14169OD of insulation, d1

Where,K = Kcal/hr-mC at mean temperature tmCtm = (th + tc)/ tath = Temperature of hot fluid, Ctc = Surface temperature of insulation, C (Usually 55 60 C)ta = Ambient temperature, C h = Heat transfer coefficient, Kcal/m2 hr C = 8.598 [A +0.005 (tc - ta)] for horizontal surface = 8.598 [B +0.009 (tc - ta)] for vertical surfaceD = OD of pipe, mmCoefficent for calculating heat transfer ceofficent (IS - 14169-Annex-c)SurfaceABAluminium bright rolled0.250.27Aluminium, oxidized0.310.33Galvanized sheet metal, blank0.40.42Galvanized sheet metal, dusty0.530.556INSULATION CONTDHeat loss from pipe,

Heat loss From Flat Surface

7INSULATION MATERIAL AND APPLICATION SN.Specification Applicationi)Resin bonded mineral wool (rock wool) mattress as per IS:8183, with factory stitched G.I. Wire netting on outer surface. For pipe sizes above DN 350 and for flat surfaces and equipmentii)Rock or Slag wool mats wire netting on both sides conforming to IS 3677Type 3 (for up to 250 C)Type 2 ( For up to 500 C)Type 1 ( For up to 900 C)iii)Glass wool mat with wire netting on both sides conforming to IS 3690 Type 2 Gr. B (for up to 450 C )Type 3 (for up to 550 C) SN.Specification Applicationiv)Pipe-sections of light resin-bonded mineral wool (rock/slag wool) as per IS:9842For pipe work upto DN 350i)Group1(50-80 Kg/m3) up to 400 Cii)Group 2 (81-120 Kg/m3) up to 400 Ciii)Group 3 (121-160Kg/m3) up to 650 Civ) Group 4 (161-250 Kg/m3) up to 750 Cv)Expanded polystyrene blocks and pipe sections/ segments conforming to IS:4671 Type 1. Self-extinguishing (type 2) material shall be used where fire hazard exists.For chilled water pipelines/valves. Board will be used for flat surfaces8THERMAL CONDUCTIVITY OF INSULATION MATERIAL Thermal conductivity of insulating material in Kcal/hr-m-CUn bonded rock and slag wool - IS 3677DensityTemperature , CKg/m350100150200250300800.042990.0481490.0481490.0584660.0877NR1000.042990.0481490.0584660.0687840.0877NR1200.041270.0464290.0567470.0670640.076522NR1500.0395510.044710.0533080.0644850.075662NRGlass Wool- IS 3690Density Kg/m3Temperature , C50100150200250300800.0369710.0447090.0550270.067064NRNR1000.0369710.0447090.0533070.062765NRNR1200.0369710.0447090.0533070.062765NRNR1500.03697140.04470960.05330760.0584664NRNRBonded Mineral Wool-IS 8183Density Kg/m3Temperature , C50100150200250300800.03697140.04470960.05502720.06706440.07996140.0945781000.03697140.04470960.05330760.06276540.07222320.0816811200.03697140.04470960.05330760.06276540.07222320.0816811500.03697140.04470960.05330760.05846640.0687840.0773829THERMAL CONDUCTIVITY OF INSULATION MATERIAL IS 9842 , Thermal conductivity in Kcal/hr-m-CMean Tempr.,CGroup 1Group 2Group 3Group 4500.03697360.03697360.0369740.0369741000.04471220.04471220.0447120.0447121500.05503040.05331070.0533110.0533112000.06706830.06276910.060190.058472500.07996610.07308730.0730870.0687883000.09458350.0859850.0859850.077387IS : 4671Density Kg/m3Temperature C010150.0292350.031814200.0275150.030095250.0257960.028375300.0249360.027515350.0240760.02665510STANDARD INSULATION THICKNESS FOR PIPES Hot ServiceCold ServicePipe SizeSteam SteamCondensateChilled water(Supply and Return)DN, mm(315oC)(190oC)(170oC)(7oC & 14oC)156040402520604540252560454025406550404050705040406575554040807555504010080555050125906050501509060505020090606075250100657575300100657575350100657575400100657575450105657575500105707575550105707575600110707575a)For hot service Outside surface temperature shall not exceed 100C above maximum ambient temperature b)For cold service Outside surface temperature shall not fall below 100C 11FLASH STEAM GENERATIONIf the pressure of the condensate - the saturated water at the boiling point at the actual pressure - is reduced, some portion of the condensate converted in steam and is called flash steam.The energy - or enthalpy - made available when the pressure is reduced, will evaporate a part of the water, producing the flash steam.

The amount of flash steam produced during the pressure reduction can be expressed as:w = (hil - hfl) / hfew = ratio of flash steam generated (kg flash steam / kg condensate)hil = initial liquid enthalpy (kJ/kg)hfl = final liquid enthalpy (kJ/kg) hfe = enthalpy of evaporation (kJ/kg)Example : Condensate at a pressure of 5 bar gauge (6 bar absolute) is reduced to atmospheric pressure - 0 bar gauge (1 bar absolute) through the steam trap. To calculate Flash steam.hil = initial liquid enthalpy (kJ/kg) of condensate at 6 bara = 670 Kj/kg hfl = Final liquid enthalpy (kJ/kg) of condensate at atmospheric pr.= 419 Kj/kg hfe = enthalpy of evaporation at atmospheric pr=2257 Kj/kgw = ((670.9 kJ/kg)- (419.0 kJ/kg)) / (2,257 kJ/kg) == 0.11 (kg flash steam / kg condensate)

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Typical flash vessel15

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