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{
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"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 2. Process Economics"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Problem 2.1, Page Number 22"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#Variable Declaration\n",
"Q = 500.0 #Heat TRansfer Area, m2\n",
"QB = 80.0 #Base Size, m2\n",
"CB = 3.28e4 #Base Cost, $\n",
"CEIc = 441.9 #Current CE Index\n",
"CEIp = 435.8 #Past CE Index\n",
"M = 0.68 #Cost exponent\n",
"fM = 2.9 #Factor for capital cost\n",
"fPIP = 0.7\n",
"fER = 0.4\n",
"fINST = 0.2\n",
"fELE = 0.1\n",
"fUTIL = 0.5\n",
"fOS = 0.2\n",
"fBUILD = 0.2\n",
"fSP = 0.1\n",
"fDEC = 1.0\n",
"fCONT =0.4\n",
"fWS = 0.7\n",
"\n",
"#Calculations\n",
"CE = CB*(Q/QB)**M\n",
"CEc = CE*(CEIc/CEIp)\n",
"CF1 = fM*(1+fPIP)*CEc + (fER + fINST + fELE + fUTIL + fOS + fBUILD + fSP + fDEC + fCONT + fWS)*CEc\n",
"CF2 = fM*(1+fPIP)*CEc + (fER + fINST + fDEC + fCONT)*CEc\n",
"#Results\n",
"print 'Capital Cost of Carbon steel exchanger $%5.3e'%CE\n",
"print CF1, CF2"
],
"language": "python",
"metadata": {},
"outputs": []
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Problem 2.2, Page Number 22"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#Variable Declaration\n",
"Q = 500.0 #Heat TRansfer Area, m2\n",
"QB = 80.0 #Base Size, m2\n",
"CB = 3.28e4 #Base Cost, $\n",
"CEIc = 441.9 #Current CE Index\n",
"CEIp = 435.8 #Past CE Index\n",
"M = 0.68 #Cost exponent\n",
"fM = 2.9 #Factor for capital cost\n",
"fPIP = 0.7\n",
"\n",
"#Calculations\n",
"CE = CB*(Q/QB)**M\n",
"CEc = CE*(CEIc/CEIp)\n",
"Cpip = fM*fPIP*CEc\n",
"#Results\n",
"print 'Piping cost $%5.3e'%Cpip"
],
"language": "python",
"metadata": {},
"outputs": []
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Problem 2.3, Page Number 24"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#Variable Declaration\n",
"Q = 1.5 #Heat TRansfer Area, m2\n",
"QB = 0.5 #Base Size, m2\n",
"H = 30.0 # Height of Packing, m\n",
"CB = 1.8e4 #Base Cost for 5m height of pkg, $\n",
"CEIc = 441.9 #Current CE Index\n",
"CEIp = 435.8 #Past CE Index\n",
"M = 1.7 #Cost exponent\n",
"Cr = 0.1 #Cost of removing old packing\n",
"Ca = 0.7 #Cost of adding new packing\n",
"\n",
"#Calculations\n",
"CE = CB*(H/5.)*(Q/QB)**M\n",
"CEc = CE*(CEIc/CEIp)\n",
"Cp = CEc*(1.0+Cr+Ca)\n",
"#Results\n",
"print 'Cost of packing $%5.2e'%CE\n",
"print 'Cost of packing corrected using cost indexes $%5.2e'%CEc\n",
"print 'total Cost of Project $%5.2e'%Cp"
],
"language": "python",
"metadata": {},
"outputs": []
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Problem 2.4, Page Number 24"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#Variable Declaration\n",
"Ci = 1.0e6 #Cost of Distillation column in Dollor\n",
"n = 5. #Number of years\n",
"i = 0.05 #Interest rate in percent\n",
"fi = 5.8 #Installation factor\n",
"\n",
"#Calculations\n",
"CF = fi*Ci\n",
"fA = i*(1.+i)**n/((1.+i)**n-1.)\n",
"CAnnualized = CF*fA\n",
"#Results\n",
"print 'Cost of installed Equipment $%8.0f'%CF\n",
"print 'Annulization factor $%5.4f'%fA\n",
"print 'Annualized cost $%8.0f per year'%CAnnualized"
],
"language": "python",
"metadata": {},
"outputs": []
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Problem 2.5, Page Number 26"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from numpy import array,zeros\n",
"from sympy import symbols, integrate\n",
"from scipy.interpolate import interp1d\n",
"from scipy.optimize import root\n",
"\n",
"#Variable Declaration\n",
"P = array([41.0,10.0,3.0]) #Array of pressure for High medium and low pressures, barg bar gauge\n",
"Ieff = 80.0 #Isentropic efficiency of steam turbine\n",
"Cfuel = 4.0e-9 #Cost of fuel, $ per J\n",
"Cele = 0.07 #Cost of electricity, $ per (kWh)\n",
"Tw = 100.0 #Temperature of boiler feed water, \u00b0C\n",
"Cpw = 4200.0 #Specific heat of water, K/(kg.K)\n",
"effSG = 85.0 #Efficiency of Steam Generation\n",
"Ts = 400.0 #Temperature of superheated steam,\u00b0C \n",
"Hs = 3212e3 #Enthalpy of steam at 400 \u00b0C and 41 barg, J/kg\n",
"Tref = 0.0 #Reference Temperature,\u00b0C\n",
"Qloss = 10.0 #Distribution losses in percent\n",
"\n",
"#Calculations\n",
"hw = Cpw*(Tw-Tref) #Enthalpy of water at 100 \u00b0C, J/kg \n",
"dHs = Hs-hw\n",
"#Cost of steam at 41.0 barg\n",
"Csg41 = dHs*Cfuel*100*(1.0+Qloss/100)/effSG\n",
"\n",
"#Cost of steam at 10.0 barg\n",
"Ss = 6747.0 #Entropy of steam at 400 \u00b0C and 41 barg\n",
"H10 = 2873000.0 #Enthalpy of steam at 10 barg\n",
"S10 = 6747.0 #Entropy of steam at 10 barg\n",
"H10dash = Hs - Ieff*(Hs - H10)/100\n",
"Pgen10 = Hs-H10dash #Power gernerated per kg of steam to convert it to 10 barg from 41 barg steam\n",
"\n",
"#Value of power gerneration due to forrmation of 10 barg steam\n",
"VP41t10 = Pgen10*Cele/(3600*1000)\n",
"Csg10 = Csg41-VP41t10\n",
"\n",
"#Cost of steam at 3.0 barg\n",
"H10 = 2941000.0 #Enthalpy of steam at 3.0 barg\n",
"S10 = 6880.0 #Entropy of steam at 3.0 barg\n",
"H3 = 2732000.0 #Enthalpy of steam at 3.0 barg\n",
"S3 = 6880.0 #Entropy of steam at 3.0 barg\n",
"H3dash = H10 -Ieff*(H10-H3)/100\n",
"#Value of power gerneration due to forrmation of 3 barg steam\n",
"Pgen3 = H10-H3dash #Power gernerated per kg of steam to convert it to 3 barg from 10 barg steam\n",
"VP10t3 = Pgen3*Cele/(3600*1000)\n",
"Csg3 = Csg10-VP10t3\n",
"\n",
"#Results\n",
"print 'Heat required to generate steam at 41 barg and 400\u00b0C from water: %8.1f J/kg'%dHs\n",
"print 'Cost of Steam generation for steam at 41 barg and 400\u00b0C from water: $ %8.6f per kg ' %Csg41\n",
"\n",
"print 'Power geration when 41 barg steam is converted to 10 barg steam : %8.1f J/kg'%Pgen10\n",
"print 'Value of when 41 barg steam is converted to 10 barg steam: $ %8.6f per kg ' %VP41t10\n",
"print 'Cost of Steam generation for steam at 10 barg from 41 barg steam: $ %8.6f per kg ' %Csg10\n",
"\n",
"print 'Power geration when 10 barg steam is converted to 3 barg steam : %8.1f J/kg'%Pgen3\n",
"print 'Value of when 10 barg steam is converted to 3 barg steam: $ %8.6f per kg ' %VP10t3\n",
"print 'Cost of Steam generation for steam at 3 barg from 10 barg steam: $ %8.6f per kg' %Csg3"
],
"language": "python",
"metadata": {},
"outputs": []
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Problem 2.6, Page Number 28"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#Variable Declaration\n",
"Qc = 0.5e6 #Cooling load, W\n",
"Tc = -20.0 #Cold Sink temperature, \u00b0C\n",
"Th = 30.0 #Hot source temperature, \u00b0C\n",
"dTmin = 5.0 #Minimum temperature difference, \u00b0C\n",
"eff = 0.6\n",
"Ce = 0.07 #Cost of electricity, $ per KWh\n",
"Hours = 8000.0 #Hours of working per year\n",
"\n",
"#Calculations\n",
"Th = Th + dTmin + 273.15\n",
"Tc = Tc - dTmin + 273.15\n",
"W = Qc/eff*((Th-Tc)/Tc)\n",
"Cele = W*Ce*Hours\n",
"\n",
"#Results\n",
"print 'Actual power required %6.0f W'%W\n",
"print 'Cost of Electriciity $ %6.0f '%(Cele/1000)"
],
"language": "python",
"metadata": {},
"outputs": []
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Problem 2.7, Page Number 30"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from numpy import array,zeros\n",
"from sympy import symbols, integrate\n",
"from scipy.interpolate import interp1d\n",
"from scipy.optimize import root\n",
"\n",
"#Variable Declaration\n",
"CP = 1.0e6 #Cost of Project, dollor\n",
"ACFA = array([-10.,1.6,2.8,4.0,5.2,6.4]) #Annual Cash Flow for Project A\n",
"ACFB = array([-10.,6.5,5.2,4.0,2.8,1.6]) #Annual Cash Flow for Project B\n",
"ADCFA = zeros(len(ACFA)) #Annual Discounted Cash Flow for Project A\n",
"ADCFB = zeros(len(ACFB)) #Annual Discounted Cash Flow for Project B\n",
"Y = array([0,1,2,3,4,5]) #Array containing disyear \n",
"j = array([20.,25.,30.,35.,40.]) #Array containing Discounted Cash Flow Rate of Return in percent\n",
"SADCFA = zeros(len(j)) #Array containing Sum of Annual Discounted Cash Flow for Project A\n",
"SADCFB = zeros(len(j)) #Array containing Sum of Annual Discounted Cash Flow for Project B\n",
"\n",
"#Calculations\n",
"\n",
"ACFA = ACFA*1e6\n",
"ACFB = ACFB*1e6\n",
"NPVA = ACFA/(1.0 + i)**Y\n",
"NPVB = ACFB/(1.0 + i)**Y\n",
"\n",
"print 'Project A:'\n",
"for n in j:\n",
" k = sorted(j).index(n)\n",
" print 'Discounted Annual Cash Flow for DCFRR %2d'%n\n",
" for m in Y:\n",
" ADCFA[m] = ACFA[m]/(1. + n/100.0)**m\n",
" SADCFA[k] = SADCFA[k] + ADCFA[m]\n",
" print 'For year %2d is %8.0f'%(m,ADCFA[m])\n",
" print 'For DCFRR of %2d%% Net Present Value is %9.0f'%(n,SADCFA[k]) \n",
" print '---------------------------------------------'\n",
"\n",
"fA = interp1d(j, SADCFA)\n",
"f = lambda x:fA(x)\n",
"sol = root(f,21)\n",
"DCFRRA = sol.x[0]\n",
"print \n",
"print 'Project B:'\n",
"for n in j:\n",
" k = sorted(j).index(n) \n",
" print 'Discounted Annual Cash Flow for DCFRR %2d'%n\n",
" for m in Y:\n",
" ADCFB[m] = ACFB[m]/(1. + n/100.0)**m\n",
" SADCFB[k] = SADCFB[k] + ADCFB[m]\n",
" ADCFB[m] = ACFB[m]/(1. + n/100.0)**m\n",
" print 'For year %2d is %8.0f'%(m, ADCFB[m])\n",
" print 'for DCFRR of %2d%% Net Present Value is %9.0f'%(n,SADCFB[k]) \n",
" print '---------------------------------------------'\n",
"\n",
"fB = interp1d(j, SADCFB)\n",
"f = lambda x:fB(x)\n",
"sol = root(f,35)\n",
"DCFRRB = sol.x[0]\n",
"\n",
"#Results\n",
"print 'Discounted Cash flow Rate of Return for Project A is: %4.2f%% and for Project B is %4.2f%%'%(DCFRRA,DCFRRB)\n",
"if DCFRRA > DCFRRB:\n",
" print 'Discounted Cash flow Rate of Return for Project A is %4.2f%% > %4.2f%% for Project B, \\nhence project A should be preffered'%(DCFRRA,DCFRRB)\n",
"else:\n",
" print 'Discounted Cash flow Rate of Return for Project A is %4.2f%% < %4.2f%% for Project B, \\nhence project B should be preffered'%(DCFRRA,DCFRRB)\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": []
}
],
"metadata": {}
}
]
}
|
