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"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 15 : Circulation Systems"
]
},
{
"cell_type": "heading",
"level": 3,
"metadata": {},
"source": [
"Example 1, Page 369\n"
]
},
{
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"collapsed": false,
"input": [
"\n",
"\n",
"import math\n",
"\n",
"#Variable declaration\n",
"thalf=1; #Half life of catalyst in s\n",
"F=960; #Feed rate of oil in tons/day\n",
"W=50; #Weight of the bed in tons\n",
"a=0.5; #Activity after time equal to half life\n",
"abar=0.01; #Average activity of the catalyst\n",
"\n",
"#CALCULATION\n",
"Ka=-math.log(a)/thalf;#Rate constant is s**-1, assuming I order kinetics from Eqn.(12)\n",
"Fs=Ka*W*abar/(1-abar);#Circulation rate of solids from Eqn.(16)\n",
"x=(Fs*60*60*24.0)/F; #Circulation rate per feed of oil\n",
"\n",
"#OUTPUT\n",
"print '\\nSolid recirculation per feed of oil =%ftons of solid circulated/ton feed oil'%x\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"\n",
"Solid recirculation per feed of oil =31.506690tons of solid circulated/ton feed oil\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 3,
"metadata": {},
"source": [
"Example 2, Page 370\n"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"#Variable declaration\n",
"deltaHr1=1260.; #Enthalpy change during endothermic reaction in kJ/kg\n",
"deltaHr2=-33900.; #Enthal[y change during exothermic reaction in kJ/kg\n",
"H1=703.; #Enthalpy of feed oil in kJ/kg\n",
"T1=260.; #Temperature of feed oil in degree celcius\n",
"H3=1419.; #Enthalpy of cracked product in kJ/kg\n",
"T3=500.; #Temperature of cracked product in degree celcius\n",
"Ta=20.; #Temperature of entering air in degree celcius\n",
"Cpa=1.09; #Specific heat of entering air in kJ/kg K\n",
"Cpf=1.05; #Specific heat of flue gases in kJ/kg K\n",
"Cps=1.01; #Specific heat of solids in kJ/kg K\n",
"Cpv=3.01; #Specific heat of vaporized feed in kJ/kg K\n",
"T4=[520.,540.,560.,580.,600.,620.,640.,660.]; #Temperature of flue gas in degree celcius\n",
"V=22.4; #Volume of 1 mole of Carbon dioxide gas in N-m**3\n",
"M=12.; #Molecular weight of carbon in kg\n",
"rho=1.293; #Density of carbon dioxide gas in kg/N-m**3\n",
"xa=0.21; #Mass fraction of oxygen in air\n",
"betac=0.07; #Mass fraction of carbon\n",
"\n",
"#CALCULATION\n",
"n=len(T4);\n",
"i=0;\n",
"x1 = [0,0,0,0,0,0,0,0]\n",
"x2 = [0,0,0,0,0,0,0,0]\n",
"excess_air = [0,0,0,0,0,0,0,0]\n",
"\n",
"x2min=betac*(V*rho/(M*xa));#Minimum amount of air required for complete combustion\n",
"while ix2min:\n",
" excess_air[i]=(x2[i]-x2min)/x2min; #Excess air used\n",
" else:\n",
" excess_air[i]=0;\n",
" i=i+1;\n",
"\n",
"#OUTPUT \n",
"print 'T4(degree celcius)',\n",
"print '\\tFs/F1',\n",
"print '\\t\\tF2/F1',\n",
"print '\\t\\tExcess air(percentage)'\n",
"i=0;\n",
"while i