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diff --git a/Applied_Thermodynamics/Chapter11.ipynb b/Applied_Thermodynamics/Chapter11.ipynb new file mode 100755 index 00000000..57bf66e3 --- /dev/null +++ b/Applied_Thermodynamics/Chapter11.ipynb @@ -0,0 +1,918 @@ +{ + "metadata": { + "name": "", + "signature": "sha256:6a2922d727738ae70604bae46fb35f03608e71a4b1a12c93dd485fb1323281a2" + }, + "nbformat": 3, + "nbformat_minor": 0, + "worksheets": [ + { + "cells": [ + { + "cell_type": "heading", + "level": 1, + "metadata": {}, + "source": [ + "Chapter 11: Boilers and Boiler Calculations" + ] + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 1, page no. 481" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "from __future__ import division\n", + "\n", + "#Variable Declaration: \n", + "H = 30 #Height of chimney(in m):\n", + "Ta = 27+273 #Ambient air temperature(in K):\n", + "m = 20 #Mass per kg of fuel required for complete combustion(in kg):\n", + "hw = 12 #Height in the water column(in mm):\n", + "\n", + "#Calculations:\n", + "Tg = (Ta*353*H)/(353*H-hw*Ta)*(m)/(m+1)#Temperature of burnt gases(in K):\n", + "\n", + "#Results:\n", + "print \"Temperature of the burnt gases: \",round(Tg,2),\"K\"" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Temperature of the burnt gases: 432.86 K\n" + ] + } + ], + "prompt_number": 3 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 2, page no. 482" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "from __future__ import division\n", + "\n", + "#Variable Declaration: \n", + "m = 18 #Mass per kg of fuel required for complete combustion(in kg):\n", + "hw = 20 #Height in the water column(in mm):\n", + "Ta = 27+273 #Ambient air temperature(in K):\n", + "Tg = 300+273 #Temperature of burnt gases(in K):\n", + "\n", + "#Calculations:\n", + "H = hw/(353*(1/Ta-(m+1)/(m*Tg)))#Height of chimney(in m):\n", + "\n", + "#Results:\n", + "print \"Height of chimney: \",round(H,2),\"m\"" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Height of chimney: 37.99 m\n" + ] + } + ], + "prompt_number": 5 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 3, page no. 482" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "from __future__ import division\n", + "\n", + "#Variable Declaration: \n", + "H = 20 #Height of chimney(in m):\n", + "Tg = 380+273 #Temperature of burnt gases(in K):\n", + "Ta = 27+273 #Ambient air temperature(in K):\n", + "\n", + "#Calculations:\n", + "m = 2*Ta/(Tg-2*Ta) #Air supplied(in kg air per fuel):\n", + "\n", + "#Results:\n", + "print \"Air supplied:\",round(m,2),\"kg/kg of fuel\"" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Air supplied: 11.32 kg/kg of fuel\n" + ] + } + ], + "prompt_number": 7 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 4, page no. 482" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "from __future__ import division\n", + "\n", + "#Variable Declaration: \n", + "H = 60 #Height of chimney(in m):\n", + "Ta = 17+273 #Ambient air temperature(in K):\n", + "Tg = 300+273 #Temperature of burnt gases(in K):\n", + "Tga = 150+273 #Temperature of the artificial burnt gases(in K):\n", + "m = 19 #Mass per kg of fuel required for complete combustion(in kg):\n", + "Cpg = 1.0032 #Specific heat of hot gases(in kJ/kg.K):\n", + "c = 32604 #Calorific value of burnt fuel(in kJ/kg):\n", + "\n", + "#Calculations:\n", + "hw = 353*H*(1/Ta-(m+1)/(m*Tg)) #Draught (in mm of water column):\n", + "n = 9.81*H*(m/(m+1)*Tg/Ta-1)/(Cpg*(Tg-Tga)*10**3)*100 #Chimney efficiency:\n", + "Q = (m+1)*Cpg*(Tg-Tga) #Extra heat carried away by flue gases(in kJ):\n", + "\n", + "#Results:\n", + "print \"Draught: \",round(hw,2),\" mm of water\"\n", + "print \"Chimney efficiency\",round(n,4),\"%\"\n", + "print \"Extra heat carried away by flue gases per kg of fuel burnt\",round(Q,1),\" kJ\"" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Draught: 34.13 mm of water\n", + "Chimney efficiency 0.3431 %\n", + "Extra heat carried away by flue gases per kg of fuel burnt 3009.6 kJ\n" + ] + } + ], + "prompt_number": 9 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 5, page no. 483" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "from __future__ import division\n", + "\n", + "#Variable Declaration: \n", + "H = 80 #Height of chimney(in m):\n", + "Ta = 27+273 #Ambient air temperature(in K):\n", + "m = 20 #Mass per kg of fuel required for complete combustion(in kg):\n", + "Tga = 110+273 #Temperature of the artificial burnt gases(in K):\n", + "Cpg = 1.0032 #Specific heat of hot gases(in kJ/kg.K):\n", + "\n", + "#Calculations:\n", + "Tg = Ta*2*(m+1)/m #Temperature of burnt gases(in K):\n", + "hw = 353*H*(1/Ta-(m+1)/(m*Tg)) #Draught in water column(in mm):\n", + "n = 9.81*H*(m/(m+1)*Tg/Ta-1)/(Cpg*(Tg-Tga)*10**3)*100 #Chimney efficiency:\n", + "\n", + "#Results:\n", + "print \"Hot gas temperature in chimney: \",round(Tg),\"K\"\n", + "print \"Natural draught: \",round(hw,2),\"mm of water\"\n", + "print \"Chimney efficiency: \",round(n,4),\"%\"" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Hot gas temperature in chimney: 630.0 K\n", + "Natural draught: 47.07 mm of water\n", + "Chimney efficiency: 0.3167 %\n" + ] + } + ], + "prompt_number": 12 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 6, page no. 484" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "from __future__ import division\n", + " \n", + "from math import sqrt,pi\n", + "\n", + "#Variable Declaration: \n", + "R = 2.5*10**3 #Rate at which coal is burnt(in kg/hr):\n", + "m = 20 #Mass per kg of fuel required for complete combustion(in kg):\n", + "Tg = 327+273 #Temperature of burnt gases(in K):\n", + "Ta = 27+273 #Ambient air temperature(in K):\n", + "h = 7+6+3+2 #Pressure head(in mm):\n", + "na = 0.90 #Ratio of actual natural draught to theoretical draught:\n", + "g = 9.81 #Acceleration due to gravity(in m/s**2):\n", + "\n", + "#Calculations:\n", + "hw = h/na #Actual natural draught(in mm of water):\n", + "H = hw/(353*(1/Ta-(m+1)/(m*Tg))) #Height of chimney(in m):\n", + "dg = 353/Tg*(m+1)/m #Density of hot gases(in kg/m**3):\n", + "hg = H*((m+1)/m*Tg/Ta-1) #Height of hot gases column(in m):\n", + "Mg = R*hw/3600 #Mass flow rate of hot gases(in kg/s):\n", + "C = sqrt(2*g*hg) #Velocity of got gases(in m/s):\n", + "D = sqrt((4*Mg)/(pi*C*dg)) #Diameter of chimney(in m):\n", + "\n", + "#Results:\n", + "print \"Height of chimney:\",round(H,2),\"m\"\n", + "print \"Diameter of chimney:\",round(D,2),\"m\"" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Height of chimney: 35.78 m\n", + "Diameter of chimney: 1.01 m\n" + ] + } + ], + "prompt_number": 14 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 7, page no. 485" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "from __future__ import division\n", + " \n", + "#Variable Declaration: \n", + "hw = 50 #Draught in water column(in mm):\n", + "T = 300+273 #Temperature of burnt gases(in K):\n", + "m = 19 #Mass per kg of fuel required for complete combustion(in kg):\n", + "T1 = 27+273 #Ambient air temperature(in K):\n", + "T0 = 273 #Zero temperature(in K):\n", + "n = 0.90 #Mechanical efficiency:\n", + "d = 1.293 #Density of hot gases(in kg/m**3):\n", + "\n", + "#Calculations:\n", + "M = 2000/3600 #Rate at which coal is burnt(in kg/s):\n", + "P = hw*9.81 #Pressure applied by the draught water(in N/m**2):\n", + "PFD = P*m*M*T1/(d*T0*n*1000) #Power required in FD fan(kW):\n", + "P1D = P*m*M*T/(d*T0*n*1000) #Power required in 1D fan(kW):\n", + "\n", + "#Results:\n", + "print \"Power for FD fan:\",round(PFD,2),\"kW\"\n", + "print \"Power for 1D fan:\",round(P1D,2),\"kW\"" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Power for FD fan: 4.89 kW\n", + "Power for 1D fan: 9.34 kW\n" + ] + } + ], + "prompt_number": 16 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8, page no. 486" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "from __future__ import division\n", + "\n", + "#Variable Declaration: \n", + "Cpg = 1.0032 #Specific heat of hot gases(in kJ/kg.K):\n", + "Tg = 177+273 #Temperature of burnt gases(in K):\n", + "Ta = 27+273 #Ambient air temperature(in K):\n", + "Tn = 327+273 #Natural draught temperature(in K):\n", + "mn = 25 #Mass per kg of fuel required for natural draught(in kg):\n", + "ma = 20 #Mass per kg of fuel required for artificial draught(in kg):\n", + "r = Tg/Ta #Ratio of brake power for induced draught to forced draught:\n", + "\n", + "#Calculations:\n", + "Qgad = (ma+1)*Cpg*(Tg-Ta) #Heat carried by hot flue gases in artificial draught(in per kg of fuel burnt):\n", + "Qgnd = (mn+1)*Cpg*(Tn-Ta) #Heat carried by hot flue gases in natural draught(in per kg of fuel burnt):\n", + "rh = Qgad/Qgnd #Ratio of heat carried away:\n", + "\n", + "#Results:\n", + "print \"Ratio of power required: \",round(r,1)\n", + "print \"Ratio of heat carried away: \",round(rh,3)" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Ratio of power required: 1.5\n", + "Ratio of heat carried away: 0.404\n" + ] + } + ], + "prompt_number": 18 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 9, page no. 486" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "from __future__ import division\n", + "\n", + "#Variable Declaration: \n", + "T = 27+273 #Feed water supply temperature(in K):\n", + "P = 10 #Mean steam generation pressure(in bar):\n", + "x = 0.95 #Dryness fravtion of steam generated:\n", + "Q = 2500 #Feed water supplied(in kg/hr):\n", + "Q1 = 275 #Coal burnt(in kg/hr):\n", + "d = 300 #Difference in mass of water after trial:\n", + "hf = 762.81 #kJ/kg #From steam tables:\n", + "hg = 2778.1 #kJ/kg\n", + "hfg = 2015.29 #kJ/kg\n", + "\n", + "#Calculations:\n", + "h = hf+x*hfg #Enthalpy of steam generated(in kJ/kg):\n", + "mw = Q+d #Mass of water evaporator per hour(in kg/hr):\n", + "Ae = mw/Q1 #Actual evaporation(in per kg of coal):\n", + "Ee = Ae*h/2257 #Equivalent evaporation(in kg per kg of coal):\n", + "\n", + "#Results:\n", + "print \"Actual evaporation: \",round(Ae,2),\" kg per kg of coal\"\n", + "print \"Equivalent evaporation: \",round(Ee,2),\"kg per kg of coal\"" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Actual evaporation: 10.18 kg per kg of coal\n", + "Equivalent evaporation: 12.08 kg per kg of coal\n" + ] + } + ], + "prompt_number": 22 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 10, page no. 487" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "from __future__ import division\n", + " \n", + "#Variable Declaration: \n", + "p = 10 #Average pressure of the steam(in bar):\n", + "Ww = 15 #Weight of water consumed(in ton):\n", + "Wc = 1.5 #Weight of coal produced(in ton):\n", + "n = 1-0.03-0.04 #Percentage coal that caan be burnt:\n", + "nm = 0.03 #Composition of moisture in coal:\n", + "Tf = 35 #Temperature of feed water(in C):\n", + "hg = 2778.1 #From steam tables(kJ/kg) \n", + "\n", + "#Calculations:\n", + "h = hg-4.18*Tf #Enthalpy of steam generated(in kJ/kg):\n", + "m = Ww/Wc #Steam generated per kg of coal(in kg):\n", + "nb = m*h/(30.1*10**3)*100 #Boiler efficiency:\n", + "Ee = m*h/(2257*(1-nm)) #Equivalent evaporation per kg of dry coal(in kg:\n", + "Eea = Ee*(1-nm)/n #Equivalent evaporation per kg of combustible present in coal(in kg):\n", + "\n", + "#Results:\n", + "print \"Boiler efficiency: \",round(nb,2),\"%\"\n", + "print \"Equivalent evaporation per kg of dry coal: \",round(Ee,2),\"kg\"\n", + "print \"Equivalent evaporation per kg of combustible present in coal: \",round(Eea,2),\"kg\"" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Boiler efficiency: 87.44 %\n", + "Equivalent evaporation per kg of dry coal: 12.02 kg\n", + "Equivalent evaporation per kg of combustible present in coal: 12.54 kg\n" + ] + } + ], + "prompt_number": 24 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 11, page no. 488" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "from __future__ import division\n", + "\n", + "#Variable Declaration: \n", + "t = 24 #Time of trial(in hrs):\n", + "p = 16 #Pressure at which steam is generated(in bar):\n", + "c = 10000 #Coal consumed(in kg):\n", + "r = 2500 #Rate of steam generation(in kg/hr):\n", + "Tf = 27 #Feed water temperature(in C):\n", + "hsa = 3000 #Total heating surface area(in m**2):\n", + "ga = 4 #Total grate area(in m**2):\n", + "C = 28000 #Calorific value of coal(in kJ/kg):\n", + "hg = 2794 #From steam tables(kJ/kg)\n", + "L = 2257 #Latent heat at 100 C:\n", + "\n", + "#Calculations:\n", + "m = c/t #Coal burnt per hour(in kg/hr):\n", + "mg = m/ga #Coal burnt per m**2 of grate per hour:\n", + "r1 = r/m #Rate of steam generated per kg of coal(in kg steam/kg coal):\n", + "Q = r1*(hg-4.18*Tf) #Heat added to steam per kg of coal(in kJ):\n", + "Ee = Q/L #Equivalent evaporation from and at 100 C per kg of coal(in kg):\n", + "Eepm = Ee*m/hsa #Equivalent evaporation from and at 100 C per m**2 of total surface per hour(in kg):\n", + "n = Ee*L/C*100 #Boiler efficiency:\n", + "\n", + "#Results:\n", + "print \"Mass of coal burnt per m**2 of grate per hour: \",round(mg,2),\"kg\"\n", + "print \"Equivalent evaporation from and at 100 C per kg of coal: \",round(Ee,2),\"kg\"\n", + "print \"Equivalent evaporation from and at 100 C per m**2 of total surface per hour: \",round(Eepm,2),\"kg\"\n", + "print \"Boiler efficiency: \",round(n,2),\"%\"" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Mass of coal burnt per m**2 of grate per hour: 104.17 kg\n", + "Equivalent evaporation from and at 100 C per kg of coal: 7.13 kg\n", + "Equivalent evaporation from and at 100 C per m**2 of total surface per hour: 0.99 kg\n", + "Boiler efficiency: 57.45 %\n" + ] + } + ], + "prompt_number": 26 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 12, page no. 489" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "from __future__ import division\n", + "\n", + "#Variable Declaration: \n", + "p = 30 #Pressure at which steam is generated(in bar):\n", + "Ts = 300 #Temperature of steam(in C):\n", + "r = 11 #Rate at which feed water enters(in kg/s):\n", + "T1 = 100 #Temperature at which feed water enters the economiser(in C):\n", + "m = 5000 #Mass of fuel used(in kg):\n", + "C = 35000 #Calorific value of fuel(in kJ/kg.K):\n", + "T = 27 #Temperature of feed water(in C):\n", + "hg = 2993.5 #From steam tables:\n", + "L = 2257 #Latent heat at 100 C:\n", + "\n", + "#Calculations:\n", + "ms = r*3600/m #Mass of steam genrated per kg of fuel(in kg/kg fuel):\n", + "Q = hg-4.18*T #Heat added per kg of fuel(in kJ):\n", + "Ee = ms*Q/L #Equivalent evaporation from and at 100 C per kg of coal(in kg):\n", + "n = Ee*L/C*100 #Boiler efficiency:\n", + "Q1 = ms*4.18*(T1-T) #Heat utilised in economiser per kg of fuel(in kJ):\n", + "P = Q1/C*100 #Percentage of energy utilised in economiser:\n", + "\n", + "#Results:\n", + "print \"Equivalent evaporation per kg of fuel: \",round(Ee,2),\"kg\"\n", + "print \"Boiler efficiency: \",round(n,2),\"%\"\n", + "print \"Percentage of energy utilised in economiser: \",round(P,1),\"%\"" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Equivalent evaporation per kg of fuel: 10.11 kg\n", + "Boiler efficiency: 65.18 %\n", + "Percentage of energy utilised in economiser: 6.9 %\n" + ] + } + ], + "prompt_number": 28 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 13, page no. 489" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "from __future__ import division\n", + "\n", + "#Variable Declaration: \n", + "m = 8 #Mass of steam genrated per kg of fuel:\n", + "Ts = 400 #Temperature of steam(in C):\n", + "p = 30 #Pressure of feed water(in bar):\n", + "T = 40 #Temperature of feed water(in C):\n", + "T1 = 150 #Temperature at which feed water leaves the economiser(in C):\n", + "x = 0.98 #Dryness fraction:\n", + "C = 29000 #Calorific value(in kJ/kg.K):\n", + "h = 3230.9 #Enthalpy of steam generated(in kJ/kg): #From steam tables:\n", + "hf = 1008.42 #kJ/kg\n", + "hfg = 1795.78 #kJ/kg\n", + "\n", + "#Calculations:\n", + "Q = h-4.18*T #Heat to be added(in kJ):\n", + "n = m*Q/C*100 #Boiler efficiency:\n", + "Q1 = 4.18*(T1-T) #Heat added in economiser per kg of steam generated(in kJ/kg):\n", + "r1 = Q1/Q*100 #Percentage fraction of heat in economiser:\n", + "Q2 = (hf+x*hfg)-4.18*T1 #Heat added in evaporator per kg of steam generated(in kJ/kg):\n", + "r2 = Q2/Q*100 #Percentage fraction of heat in economiser:\n", + "Q3 = Q-Q1-Q2 #Heat added in super heater per kg of steam generated by difference(in kJ/kg):\n", + "r3 = Q3/Q*100 #Percentage fraction of heat in economiser:\n", + "\n", + "#Results:\n", + "print \"Boiler efficiency: \",round(n,2),\"%\"\n", + "print \"Percentage fraction of heat in economiser: \",round(r1,2),\"%\"\n", + "print \"Percentage fraction of heat in evaporator: \",round(r2,2),\"%\"\n", + "print \"Percentage fraction of heat in superheater: \",round(r3,2),\"%\"" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Boiler efficiency: 84.52 %\n", + "Percentage fraction of heat in economiser: 15.01 %\n", + "Percentage fraction of heat in evaporator: 69.89 %\n", + "Percentage fraction of heat in superheater: 15.1 %\n" + ] + } + ], + "prompt_number": 30 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 14, page no. 490" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "from __future__ import division\n", + "\n", + "#Variable Declaration: \n", + "T1 = 20 #Temperature at which feed water enters and leaves the economiser(in C):\n", + "T2 = 125\n", + "r = 3 #Rate at which feed water leaves the economiser(in kg/s):\n", + "T3 = 425 #Temperature of flue gases at inlet and outlet of economiser(in C):\n", + "T4 = 300\n", + "r1 = 18 #Rate at which coal is supplied(in kg/min):\n", + "nc = 0.80 #% of C in coal:\n", + "Cpg = 1.05 #Specific heat of flue gases(in kJ/kg.K):\n", + "Ta = 15 #Atmospheric temperature(in C):\n", + "m1 = 23.65 #Mass of dry flue gases at inlet and exit of economiser(in kg):\t\t\t\t#From table:\n", + "m2 = 24.78\n", + "\n", + "#Calculations:\n", + "A = m2-m1 #Air leakage in economiser per kg of coal:\n", + "Q1 = m1*Cpg*T3+A*Cpg*Ta #Heat entering economiser with flue gases and leakage(in kJ):\n", + "Q2 = m2*Cpg*T4 #Heat entering economiser with flue gases and leakage(in kJ):\n", + "Q = Q1-Q2 #Heat lost in economiser per kg of coal(in kJ):\n", + "Q3 = (r*60/r1)*4.18*(T2-T1)\t#Heat picked up by feed water in economiser per kg of coal(in kJ):\n", + "\n", + "#Results:\n", + "print \"Heat released by the flue gases: \",round(Q,2),\"kJ per kg of coal\"\n", + "print \"Air leakage: \",round(A,2),\"kg per kg of coal\"\n", + "print \"Heat gained by feed water: \",round(Q3),\"kJ per kg of coal\"\n", + "print \"___Please check there is a calculation mistake in book in calculating Q3____\"" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Heat released by the flue gases: 2765.91 kJ per kg of coal\n", + "Air leakage: 1.13 kg per kg of coal\n", + "Heat gained by feed water: 4389.0 kJ per kg of coal\n", + "___Please check there is a calculation mistake in book in calculating Q3____\n" + ] + } + ], + "prompt_number": 32 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 15, page no. 492" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "from __future__ import division\n", + "\n", + "#Variable Declaration: \n", + "CpKg = 0.84 #Carbon present per kg:\n", + "CpKgDf = 0.0495 #Carbon present per kgof dry fluegas:\n", + "sg = 8 #Steam generated (kg per kg of coal):\n", + "mh = 0.04*9 #H2O produced during the combustion(kg per kg of coal):\n", + "ash = 0.05 #Ash produced duing cumbustion(kg per kg of coal):\n", + "M = 0.015 #Moisture in coal burnt per kg of coal:\n", + "h = 3213.6 #Enthalpy of heat generated at 40 bar 400\u00b0C (KJ/Kg):\n", + "C = 4.18 #Heat capacity of water (KJ/Kg.K):\n", + "Ti = 27 #Feed water temperature at inlet to economiser (\u00b0C):\n", + "Te = 137 #Feed water temperature at exit of economiser(\u00b0C):\n", + "Tfe = 300 #Flue gas temperature entering air heater(\u00b0C):\n", + "Tae = 120 #Temperature of air entering boiler furnace(\u00b0C):\n", + "Tatm = 15 #Atmospheric air temperature(\u00b0C):\n", + "Hs = 32600 #Heat supplied by the fuel(KJ/Kg coal):\n", + "cp = 1.0032 #Heat capacity of air and dry gas (KJ/Kg.K):\n", + "sp = 2.0064 #Specific pressure of vapour(KJ/Kg.K):\n", + "\n", + "#Calculations:\n", + "md = CpKg/CpKgDf #Mass of dry flue gas per kg of coal: #Specific pressure of vapour = 2.0064 kJ/kg K\t\t\t\t#Partial pressure of vapour in flue gas = 0.075 bar\t\t\t\t#For air and dry flue gas, cp = 1.0032 kJ/kg K\t\t\t\t#Calorific value of coal = 32600 kJ/kg\t\t\t\t#Datum temperature = 15C\t\t\t\t#Dry flue gas composition by volume = 12.5% CO2, 7.5% O2, 80% N2\t\t\t\t#Dry coal composition by mass = 84% C, 4% H2, 7% O2 and remainder ash\t\t\t\t#Temperature of air entering boiler furnace = 120C\t\t\t\t#Flue gas temperature leaving air heater and entering chimney = 150C\t\t\t\t#Flue gas temperature entering air heater = 300C\t\t\t\t#Moisture in coal burnt = 1.5%\t\t\t\t#Feed water temperature at exit of economiser = 137C\t\t\t\t#Feed water temperature at inlet to economiser = 27C\t\t\t\t#Steam generated per kg of coal = 8 kg\t\t\t\t#Steam generation: 40 bar, 400C\t\t\t\t#Atmospheric air temperature: 15C\n", + "ma = md-(1-ash-mh) #Amount of air supplied for combustion of one kg of dry coal(in kg):\n", + "m = M/(1-M) #Moisture per kg of dry coal(in kg):\n", + "mt = round(mh+m,4)#Total moisture per kg of coal(in kg):\n", + "sgd = sg/(1-M) #Steam generated per kg of dry coal(in kg steam):\n", + "H = sgd*(h-C*Ti) #Heat utilized by steam per kg of coal(KJ):\n", + "n = H/Hs*100 #Boiler efficiency:\n", + "Hu = ma*cp*(Tae-Tatm) #Heat utilized by air(KJ/Kg of coal)\n", + "Ha = (md*cp+mt*sp)*(Tfe-Te) #Heat available in air heater(KJ/Kg of coal):\n", + "na = Hu/Ha*100 #Efficiency of heat exchange in air heater:\n", + "\n", + "#Results:\n", + "print \"Boiler efficiency: \",round(n,2),\"%\"\n", + "print \"Efficiency of heat exchange in air heater: \",round(na,2),\"%\"" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Boiler efficiency: 77.25 %\n", + "Efficiency of heat exchange in air heater: 59.54 %\n" + ] + } + ], + "prompt_number": 34 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 17, page no. 496" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "from __future__ import division\n", + "\n", + "#Variable Declaration: \n", + "p = 20 #Pressure at which steam is generated(in bar):\n", + "Ts = 300 #Temperature at which steam is generated(in C):\n", + "T1 = 50 #Temperature of feed water supplied to the boiler(in C):\n", + "C = 30000 #Calorific value of fuel(in kJ/kg):\n", + "r = 600 #Rate at which coal is used(in kg/hr):\n", + "r1 = 5000 #Rate at which steam is generated(in kg/hr):\n", + "T = 100 #Temperature of the boiler unit(in C):\n", + "L = 2257 #Latent heat(in kJ/kg.K):\n", + "\n", + "#Calculations:\n", + "ms = r1/r #Steam generation per unit coal burnt per hour:\n", + "hfi = 3023.5 #Final enthalpy of the steam(in kJ/kg):\n", + "hfw = 209.33 #Enthalpy of feed water(in kJ/kg):\n", + "no = ms*(hfi-hfw)/C*100 #Overall efficiency of boiler:\n", + "Ee = ms*(hfi-hfw)/L #Equivalent evaporation of boiler unit(in kg steam per kg of coal):\n", + "Eea = Ee*r #Equivalent evaporation of boiler unit at 100 C(in kg/hr):\n", + "hfw1 = 313.93 #After fitting economiser the enthalp of feed water(in kJ/kg):\n", + "nom = no+5 #Modified overall efficiency of boiler unit:\n", + "mc = (hfi-hfw1)*r1*100/(C*nom) #Coal consumption(in kg/hr):\n", + "s = r-mc #Saving of coal(in kg/hr):\n", + "\n", + "#Results:\n", + "print \"Saving of coal: \",round(s,2),\"kg/hr\"" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Saving of coal: 57.03 kg/hr\n" + ] + } + ], + "prompt_number": 36 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 18, page no. 497" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "from __future__ import division\n", + "\n", + "#Variable Declaration: \n", + "r = 5000 #Rate at which steam is generated(in kg/hr):\n", + "p = 20 #Pressure of steam(in bar):\n", + "x = 0.98 #Dryness fraction:\n", + "T = 60 #Temperature of feed water(in \u00b0C):\n", + "r1 = 600 #Rate at which coal is supplied(in kg/hr):\n", + "r2 = 16 #Rate at which air is supplied(in kg per kg coal):\n", + "C = 30000 #Cslorific value of coal(in kJ/kg):\n", + "Tr = 20 #Temperature of boiler room(in \u00b0C):\n", + "nl = 0.86 #Fraction of heat losr with flue gases:\n", + "Cpg = 1.005 #Specific heat of flue gases(in kJ/kg.K):\n", + "#From steam tables:\n", + "hf = 908.79 #kJ/kg\n", + "hfg = 1890.7 #kJ/kg\n", + "\n", + "#Calculations:\n", + "ms = r/r1 #Mass of steam genrated per kg of coal:\n", + "hfi = hf+x*hfg #Enthalpy of final steam produced(in kJ/kg):\n", + "hfw = 251.13 #Enthalpy of feed water(in kJ/kg):\n", + "Q = ms*(hfi-hfw) #Heat used for steam generation(in kJ per kg of coal):\n", + "Ql = C-Q #Heat lost per kg of coal:\n", + "Qlf = nl*Ql #Heat lost with flue gases(in kJ per kg of coal):\n", + "Tgas = Tr+Qlf/((r2+1)*Cpg) #Temperature of flue gases(in \u00b0C):\n", + "\n", + "#Results:\n", + "print \"Temperature of flue gases: \",round(Tgas,2),\" \u00b0C\"" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Temperature of flue gases: 476.99 \u00b0C\n" + ] + } + ], + "prompt_number": 38 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 19, page no. 498" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "from __future__ import division\n", + " \n", + "#Variable Declaration: \n", + "Ta = 20+273 #Ambient temperature(in K):\n", + "V = 20 #Velocity(in m/s):\n", + "hw1 = 30 #Draught lost through grate(in mm of water column):\n", + "nm = 0.80 #Mechanical efficiency:\n", + "mf = 1000 #Rate at which coal is burnt(in kg/hr):\n", + "ma = 16 #Rate at which air is supplied(in kg/hr):\n", + "pa = 1.01325 #Ambient pressure(in bar):\n", + "d = 1.29 #Density of air(in kg/m**3):\n", + "g = 9.81 #Acceleration due to gravity(in m/s**2):\n", + "T0 = 273 #Zero temperature(in K):\n", + "\n", + "#Calculations:\n", + "P1 = d*V**2/2 #Pressure equivalent to velocity head(in N/m**2):\n", + "P = P1/g #mm of water column\n", + "hw = hw1+P #Total draught loss(in mm of water column):\n", + "p = hw*g #Pressure required(in N/m**2):\n", + "PFD = p*mf*ma*Ta/(d*T0*nm*3600) #F.D. fan power requirement(in W):\n", + "\n", + "#Results:\n", + "print \"F.D. fan power: \",round(PFD/10**3,2),\"KW\"" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "F.D. fan power: 2.55 KW\n" + ] + } + ], + "prompt_number": 40 + } + ], + "metadata": {} + } + ] +}
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