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{
"metadata": {
"name": "",
"signature": "sha256:49d323999697626f705831867b32f6c520c5287d76ed00656f7259e6db65356e"
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter15:CHEMICAL REACTIONS"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex15.1:Pg-621"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#ques1\n",
"#theoratical air-fuel ratio for combustion of octane\n",
"#combustion equation is\n",
"#C8H18 + 12.5O2 + 12.5(3.76) N2 \u2192 8 CO2 + 9H2O + 47.0N2\n",
"rm=(12.5+47.0)/1;#air fuel ratio on mole basis\n",
"rma=rm*28.97/114.2;#air fuel ratio on mass basis;\n",
"print \"Theoratical air fuel ratio on mass basis is\",round(rma),\"kg air/kg fuel\"\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
" Theoratical air fuel ratio on mass basis is 15.0 kg air/kg fuel\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex15.6:Pg-629"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#ques6\n",
"#determining heat transfer per kilomole of fuel entering combustion chamber\n",
"\n",
"#1-CH4\n",
"#2-CO2\n",
"#3-H2O\n",
"#hf-standard enthalpy of given substance\n",
"hf1=-74.873;#kJ\n",
"hf2=-393.522;#kJ\n",
"hf3=-285.830;#kJ\n",
"Qcv=hf2+2*hf3-hf1;#kJ\n",
"print \"Heat transfer per kilomole of fuel entering combustion chamber is\",round(Qcv,3),\"kJ\"\n",
"#the answers in the book is different as they have not printed the decimals in values"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Heat transfer per kilomole of fuel entering combustion chamber is -890.309 kJ\n"
]
}
],
"prompt_number": 5
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex15.7:Pg-631"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#ques7\n",
"#calculating enthalpy of water at given pressure and temperature\n",
"\n",
"#1.Assuming steam to be an ideal gas with value of Cp\n",
"T1=298.15;#Initial temperature in K\n",
"T2=573.15;#final temperature in K\n",
"T=(T1+T2)/2;#average temperature in K\n",
"Cp=1.79+0.107*T/1000+0.586*(T/1000)**2-.20*(T/1000)**3;#specific heat at constant pressure in kj/kg.K\n",
"M=18.015;#mass in kg\n",
"dh=M*Cp*(T2-T1);#enthalpy change in kJ/kmol\n",
"ho=-241.826;#enthalpy at standard temperature and pressure in kJ/mol\n",
"htp1=ho+dh/1000;#enthalpy at given temp and pressure in kJ/kmol\n",
"print \" 1. Enthalpy of water at given pressure and temperature using value of Cp =\",round(htp1,3),\"kJ/kmol\"\n",
"\n",
"#2..Assuming steam to be an ideal gas with value for dh\n",
"dh=9359;#enthalpy change from table A.9 in kJ/mol\n",
"htp2=ho+dh/1000;#enthalpy at given temp and pressure in kJ/kmol\n",
"print \" 2. Enthalpy of water at given pressure and temperature assuming value od dh =\",round(htp2,3),\"kJ/kmol \"\n",
"\n",
"#3. Using steam table\n",
"dh=M*(2977.5-2547.2);#enthalpy change for gases in kJ/mol\n",
"htp3g=dh/1000+ho;\n",
"dh=M*(2977.5-104.9);#enthalpy change for liquid in kJ/mol\n",
"hl=-285.830;#standard enthalpy for liquid in kJ/kmol\n",
"htp31=hl+dh/1000.0;#enthalpy at given temp and pressure in kJ/kmol\n",
"print \" 3.(i) enthalpy at given temp and pressure in kJ/kmol in terms of liquid =\",round(htp31,3),\"kJ/kmol \"\n",
"print \" 3.(ii) enthalpy at given temp and pressure in kJ/kmol in terms of liquid =\",round(htp3g,3),\"kJ/kmol \"\n",
"#4.using generalised charts\n",
"#htp=ho-(h2*-h2)+(h2*-h1*)+(h1*-h1);\n",
"#h2*-h2=Z*R*Tc,\n",
"#h2*-h1*=9539 kJ/mol, from part 2\n",
"#h1*-h1=0 ,as ideal gas \n",
"Z=0.21;#from chart\n",
"R=8.3145;#gas constant in SI units\n",
"Tc=647.3;#critical temperature in K\n",
"htp4=ho+9539/1000-Z*R*Tc/1000;#enthalpy at given temp and pressure in kJ/kmol\n",
"print \" 4. enthalpy at given temp and pressure in kJ/kmol using compressibility chart = \",round(htp4,3),\"kJ/kmol\"\n",
"#the answers in book are different as they have not printed the decimals in values"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
" 1. Enthalpy of water at given pressure and temperature using value of Cp = -232.258 kJ/kmol\n",
" 2. Enthalpy of water at given pressure and temperature assuming value od dh = -232.826 kJ/kmol \n",
" 3.(i) enthalpy at given temp and pressure in kJ/kmol in terms of liquid = -234.08 kJ/kmol \n",
" 3.(ii) enthalpy at given temp and pressure in kJ/kmol in terms of liquid = -234.074 kJ/kmol \n",
" 4. enthalpy at given temp and pressure in kJ/kmol using compressibility chart = -233.956 kJ/kmol\n"
]
}
],
"prompt_number": 12
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex15.15:Pg-649"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#ques15\n",
"#calculatng reversible elecromotive force \n",
"\n",
"#1-H2O\n",
"#2-H2\n",
"#3-O2\n",
"#hf-standard enthalpy \n",
"#sf-standard entropy\n",
"hf1=-285.830;#kJ\n",
"hf2=0;#kJ\n",
"hf3=0;#kJ\n",
"sf1=69.950;#kJ/K\n",
"sf2=130.678;#kJ/K\n",
"sf3=205.148;#kJ/K\n",
"dH=2*hf1-2*hf2-hf3;#change in enthalpy in kJ\n",
"dS=2*sf1-2*sf2-sf3;#change in entropy in kJ/K\n",
"T=298.15;#temperature in K\n",
"dG=dH-T*dS/1000;#change in gibbs free energy in kJ\n",
"E=-dG*1000/(96485*4);#emf in V\n",
"print\" Reversible electromotive Force =\",round(E,3),\" V\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
" Reversible electromotive Force = 1.229 V\n"
]
}
],
"prompt_number": 15
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex15.17:Pg-654"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#ques17\n",
"#efficiency of generator and plant\n",
"\n",
"q=325000*(3398.3-856.0);#heat transferred to H2O/kg fuel in kJ/kg\n",
"qv=26700.0*33250;#higher heating value in kJ/kg\n",
"nst=q/qv*100;#efficiency of steam generator\n",
"w=81000.0*3600;#net work done in kJ/kg\n",
"nth=w/qv*100.0;#thermal efficiency\n",
"print\" Efficiency of generator =\",round(nst,1),\"percent\\n\"\n",
"print\" Thermal Efficiency =\",round(nth,1),\" percent\"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
" Efficiency of generator = 93.1 percent\n",
"\n",
" Thermal Efficiency = 32.8 percent\n"
]
}
],
"prompt_number": 20
}
],
"metadata": {}
}
]
}
|
