{ "metadata": { "name": "", "signature": "sha256:57baf6d72b0852fbedefdd618b07a013f83f99bf6037a025a931e79491c28af0" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter 14 - Energies associated with chemical reactions" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 1 - Pg 297" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#calculate the HHV and LHV at constant volume\n", "#Initalization of variables\n", "lhs=8.5 #moles of reactants\n", "rhs=6 #moles of CO2\n", "n=3. #moles of H2O\n", "R=1545. #Universal gas constant\n", "R2=18.016 #molar mass of water\n", "J=778. #Work conversion constant\n", "T=537. #R\n", "T2=1050.4 #R\n", "T3=991.3 #R\n", "Qhp=1417041. #Btu/mol\n", "#calculations\n", "Qhpv=(lhs-rhs)*R*T/J\n", "Qhv=Qhp-Qhpv\n", "hfg=(rhs-n)*R2*T2\n", "Qlp=Qhp-hfg\n", "Qlpv=(lhs-rhs-n)*R/J *T\n", "Qlv=Qlp-Qlpv\n", "Qhlv=(rhs-n)*R2*T3\n", "Qlv3=Qhv-Qhlv\n", "#results\n", "print '%s %d %s' %(\"Higher heating value at constant volume =\",Qhv,\"Btu/mol\")\n", "print '%s %d %s' %(\"\\n Lower heating value at constant pressure =\",Qlp,\"Btu/mol\")\n", "print '%s %d %s' %(\"\\n In case 1,Lower heating value at constant volume =\",Qlv,\" Btu/mol\")\n", "print '%s %d %s' %(\"\\n In case 2,Lower heating value at constant volume =\",Qlv3,\"Btu/mol\")\n", "print '%s' %(\"The answers might differ a bit from textbook due to rounding off error.\")\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Higher heating value at constant volume = 1414374 Btu/mol\n", "\n", " Lower heating value at constant pressure = 1360268 Btu/mol\n", "\n", " In case 1,Lower heating value at constant volume = 1360802 Btu/mol\n", "\n", " In case 2,Lower heating value at constant volume = 1360797 Btu/mol\n", "The answers might differ a bit from textbook due to rounding off error.\n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 2 - Pg 301" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#calculate the change in chemical energy during complete combustion and LHV at constant volume\n", "#Initalization of variables\n", "print '%s' %(\"From table 5-4,\")\n", "no=7.5\n", "n1=3.\n", "n2=6.\n", "Q=1360805. #Btu/mol\n", "#calculations\n", "Uo=337+no*85\n", "Uf=n1*104+n2*118\n", "delo= Q-(Uo-Uf)\n", "Uo2=1656+no*402\n", "Uf2=n1*490+n2*570\n", "Qv=Uo2-Uf2+delo\n", "#results\n", "print '%s %d %s' %(\"Change in chemical energy during complete combustion =\",delo,\"Btu/mol\")\n", "print '%s %d %s' %(\"\\n Lower heating value at constant volume =\",Qv,\"Btu/mol\")\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "From table 5-4,\n", "Change in chemical energy during complete combustion = 1360850 Btu/mol\n", "\n", " Lower heating value at constant volume = 1360631 Btu/mol\n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 3 - Pg 302" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#calculate the heat removed in the process\n", "#Initalization of variables\n", "print '%s' %(\"From table 5-4,\")\n", "a=1 #moles of C6H6\n", "b=7.5 #moles of O2 in reactant\n", "c=1.875 #moles of excess O2\n", "d=35.27 #moles of N2\n", "e=3 #moles of H2O\n", "flow=40. #lb/min\n", "w=1360850. #Btu/mol\n", "#calculations\n", "U11=a*337\n", "U12=(b+c)*85\n", "U13=d*82\n", "U14=(a+b+c+d)*1066\n", "Ua1=U11+U12+U13+U14\n", "U21=c*2539\n", "U22=d*2416\n", "U23=e*3009\n", "U24=2*e*3852\n", "U25=(c+d+e+2*e)*1985\n", "Ua2=U21+U22+U23+U24+U25\n", "Q=Ua1+w-Ua2\n", "fuel=flow/(6*12+2.*e)\n", "Q2=Q*fuel\n", "#results\n", "print '%s %d %s' %(\"Heat removed =\",Q2,\"Btu/min\")\n", "print '%s' %(\"The answers might differ a bit from textbook due to rounding off error.\")" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "From table 5-4,\n", "Heat removed = 615294 Btu/min\n", "The answers might differ a bit from textbook due to rounding off error.\n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 4 - Pg 305" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#calculate the furnace efficiency\n", "#Initalization of variables\n", "rate=10700. #lb/min\n", "t2=97.90 \n", "t1=33.05 \n", "r1=46. #lb/min\n", "#calculations\n", "print '%s' %(\"From steam tables,\")\n", "Hv=1417041.\n", "Qw=rate*(t2-t1)\n", "Q=r1/(12*6+6) *Hv\n", "eff=Qw/Q*100.\n", "#results\n", "print '%s %.1f %s' %(\"Furnace efficiency =\",eff,\"percent\")\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "From steam tables,\n", "Furnace efficiency = 83.0 percent\n" ] } ], "prompt_number": 4 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 5 - Pg 306" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#calculate the thermal efficiency\n", "#Initalization of variables\n", "rate=94. #lb/hr\n", "hp=197. #hp\n", "c=8.\n", "h=18.\n", "Lv=17730. #Btu/hr\n", "H=2368089. #Btu/hr\n", "#calculations\n", "amount=rate*c/12 +h\n", "amount=0.824\n", "Lvv=H-Lv\n", "eff=hp*2544/(amount*Lvv) *100\n", "#results\n", "print '%s %.2f %s' %(\"Thermal efficiency =\",eff,\" percent\")\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Thermal efficiency = 25.88 percent\n" ] } ], "prompt_number": 5 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6 - Pg 306" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#calculate the thermal efficiency\n", "#Initalization of variables\n", "rate=94. #lb/hr\n", "hp=197. #hp\n", "c=8.\n", "h=18.\n", "mole=9.\n", "H=2350359. #Btu/hr\n", "#calculations\n", "amount=rate*c/12 +h\n", "amount=0.824\n", "Lvv=H-mole*18.016*1050.4\n", "eff=hp*2544/(amount*Lvv) *100\n", "#results\n", "print '%s %.2f %s' %(\"Thermal efficiency =\",eff,\"percent\")\n", "print '%s' %(\"The answer in the textbook is a different due to rounding off error\")\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Thermal efficiency = 27.90 percent\n", "The answer in the textbook is a different due to rounding off error\n" ] } ], "prompt_number": 6 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 7 - Pg 307" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#calculate the total available energy\n", "#Initalization of variables\n", "import math\n", "hv=14000. #Btu/lb\n", "ef=0.4\n", "tmin=80. #F\n", "tmid=300. #F\n", "m=13. #lb\n", "c=0.27\n", "tmean=2300. #F\n", "#calculations\n", "heat=ef*hv\n", "Qavail=heat*(tmean-tmin)/(tmean+460)\n", "Q=m*c*(tmean-tmid)\n", "Q2=Q- (tmin+460)*m*c*math.log((tmean+460)/(tmid+460))\n", "tot=Qavail+Q2\n", "#results\n", "print '%s %d %s' %(\"Total available energy =\",tot,\" Btu/lb of fuel\")\n", "print '%s' %(\"The answer is a bit different due to rounding off error in textbook\")\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Total available energy = 9079 Btu/lb of fuel\n", "The answer is a bit different due to rounding off error in textbook\n" ] } ], "prompt_number": 7 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 8 - Pg 308" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#calculate the max amount of work available\n", "#Initalization of variables\n", "print '%s' %(\"From table 14-2,\")\n", "G1=55750. #Btu/mol\n", "co2=-169580. #Btu/mol\n", "h2o=-98290. #Btu/mol\n", "#calculations\n", "G2=6*co2+3*h2o\n", "avail=G1-G2\n", "#results\n", "print '%s %d %s' %(\"Max. amount of work =\",avail,\"Btu/mol\")\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "From table 14-2,\n", "Max. amount of work = 1368100 Btu/mol\n" ] } ], "prompt_number": 8 } ], "metadata": {} } ] }