{ "metadata": { "name": "" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter 17 : Two Phase Gas Liquid Systems Saturation Condensation and Vaporization" ] }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ " Example 17.1 Page no. 511\n" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Variables\n", "F = 1. ;\t\t\t#H2C2O4- [mol]\n", "ex_O2 = 248. ;\t\t#Excess air- [%]\n", "f_C = 65/100. ;\t\t# Fraction of Carbon which convert to CO2\n", "P = 101.3 ;\t\t\t# Atmospheric pressure-[kPa]\n", "\n", "# Calculations\n", "O2_req = F*0.5 ;\t\t\t# O2 required by the above reaction-[mol]\n", "O2_in = (1. + ex_O2*F/100)*0.5 ;\t\t\t# Mol. of O2 entering\n", "\n", "# Use Elemental balance moles of species in output \n", "n_CO2 = f_C*2 ;\t\t\t# [mol]\n", "n_H2O = (2*F)/2. ;\t\t# From 2H balance-[mol]\n", "n_N2 = ((O2_in*0.79)/(0.21)) ;\t\t\t# From 2N balance-[mol]\n", "n_CO = 2-n_CO2 ;\t\t\t # From C balance-[mol]\n", "n_O2 = ((4 + O2_in*2)-(n_H2O + n_CO + 2*n_CO2))/2 ;\t\t\t# From O2 balance-[mol]\n", "total_mol = n_CO2 + n_H2O + n_N2 + n_CO + n_O2 ;\t\t\t# Total moles in output stream-[mol]\n", "y_H2O = n_H2O/total_mol ;\t# Mole fraction of H2O\n", "pp_H2O = y_H2O*P ;\t\t\t# Partial pressure of H2O-[kPa]\n", "\n", "\n", "# Results\n", "print 'Partial pressure of H2O %.2f kPa.'%pp_H2O\n", "print 'Use partial pressure of H2O to get dew point temperature T from steam table: T = 316.5 K'\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Partial pressure of H2O 9.10 kPa.\n", "Use partial pressure of H2O to get dew point temperature T from steam table: T = 316.5 K\n" ] } ], "prompt_number": 7 }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ " Example 17.2 Page no. 517\n" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Variables\n", "gas = 1. ;\t\t\t# Entering gas-[g mol]\n", "T = 26. ;\t\t\t# Temperature (for isothermal process)-[degree C]\n", "vp = 99.7 ;\t\t\t# vapour pressure of benzene at 26 C-[mm of Hg]\n", "\n", "# Analysis of entering gas \n", "f_C6H6 = 0.018 ;\t\t\t# Mol fraction of benzene\n", "f_air = 0.982 ;\t\t\t# Mol fraction of air\n", "mol_C6H6 = 0.018*gas ;\t\t# Moles of benzene-[g mol]\n", "mol_air = 0.982*gas ;\t\t# Moles of air-[g mol]\n", "\n", "# Calculations\n", "# Analysis of exit gas\n", "C6H6_rec = 95./100 ;\t\t\t# Fraction of benzene recovered\n", "C6H6_out = 1-C6H6_rec ;\t\t#Fraction of benzene in exit stream\n", "C6H6_out = mol_C6H6*C6H6_out ;\t#Moles of benzene in exit stream-[g mol]\n", "air_out = mol_air ;\t\t\t #Moles of air in exit stream-[g mol]\n", "total_mol = C6H6_out+air_out ;\t# Total moles in exit stream\n", "y_C6H6_out = C6H6_out/total_mol ;\t\t\t# Mole fraction of benzene in exit\n", "P = vp/y_C6H6_out ;\t\t\t # Pressure total of exit\n", "\n", "# Results\n", "print ' Pressure total at exit of compressor %.2e mm of Hg.'%P\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ " Pressure total at exit of compressor 1.09e+05 mm of Hg.\n" ] } ], "prompt_number": 8 }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ " Example 17.3 Page no. 519\n" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Variables\n", "ex_air = .4 ;\t\t\t# Fraction of excess air required\n", "w_C = 12. ;\t\t\t # Mol. wt. of C-[g]\n", "mol_C = 71./w_C ;\t\t#[kg mol]\n", "w_H2 = 2.016 ;\t\t\t# Mol. wt. of H2 - [g] \n", "mol_H2 = 5.6/w_H2;\n", "air_O2 = 0.21;\t\t\t# Fraction of O2 in air\n", "air_N2 = 0.79;\t\t\t# Fraction of N2 in air\n", "\n", "# Calculations\n", "CO2_1 = 1. ;\t\t\t# By Eqn. (a) CO2 produced -[kg mol]\n", "H2O_1 = 2. ;\t\t\t# By Eqn. (a) H2O produced -[kg mol]\n", "Req_O2_1 = 2. ;\t\t\t# By Eqn. (a) -[kg mol]\n", "ex_O2_1 = Req_O2_1*ex_air ;\t\t\t# Excess O2 required -[kg mol]\n", "O2_1 = Req_O2_1 + ex_O2_1 ;\t\t\t # Total O2 required - [kg mol]\n", "N2_1 = O2_1*(air_N2/air_O2) ;\t\t\t#Total N2 required - [kg mol]\n", "Total_1 = CO2_1 + H2O_1 + N2_1 + ex_O2_1 ;\t\t\t# Total gas produced- [kg mol]\n", "\n", "CO2_2 = 1 ;\t\t\t# By Eqn. (a) CO2 produced -[kg mol]\n", "H2O_2 = mol_H2/mol_C ;\t\t\t# By Eqn. (a) H2O produced -[kg mol]\n", "Req_O2_2 = 1 + (mol_H2/mol_C)*(1./2) ;\t\t\t# By Eqn. (b) and (c) -[kg mol]\n", "ex_O2_2 = Req_O2_2*ex_air ;\t\t\t# Excess O2 required -[kg mol]\n", "O2_2 = Req_O2_2 + ex_O2_2; \t\t\t# Total O2 required - [kg mol]\n", "N2_2 = O2_2*(air_N2/air_O2); \t\t\t#Total N2 required - [kg mol]\n", "Total_2 = CO2_2 + H2O_2 + N2_2 + ex_O2_2 ;\t\t\t# Total gas produced- [kg mol]\n", "\n", "P = 100. ;\t\t\t# Total pressure -[kPa]\n", "p1 = P*(H2O_1/Total_1) ;\t\t\t# Partial pressure of water vapour in natural gas - [kPa]\n", "Eq_T1 = 52.5 ;\t\t\t# Equivalent temperature -[degree C]\n", "p2 = P*(H2O_2/Total_2) ;\t\t\t# Partial pressure of water vapour in coal - [kPa]\n", "Eq_T2 = 35 ;\t\t\t# Equivalent temperature -[degree C]\n", "\n", "# Results\n", "print ' Natural gas Coal'\n", "print ' ---------------------- --------------------'\n", "print 'Partial pressure: %.1f kPa %.1f kPa'%(p1,p2 )\n", "print 'Equivalent temperature: %.1f C %.1f C'%(Eq_T1,Eq_T2 );\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ " Natural gas Coal\n", " ---------------------- --------------------\n", "Partial pressure: 14.0 kPa 5.5 kPa\n", "Equivalent temperature: 52.5 C 35.0 C\n" ] } ], "prompt_number": 9 }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ " Example 17.4 Page no. 522\n" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Variables\n", "F = 30. ;\t\t\t# Volume of initial gas-[m**3]\n", "P_F = 98.6 ;\t\t\t# Pressure of gas-[kPa]\n", "T_F = 273.+100 ;\t\t\t# Temperature of gas-[K]\n", "P_p = 109. ;\t\t\t#[kPa]\n", "T_p = 14.+273 ;\t\t\t# Temperature of gas-[K]\n", "R = 8.314 ;\t\t\t# [(kPa*m**3)/(k mol*K)] \n", "# Additional condition\n", "vpW_30 = 4.24 ;\t\t\t#Vapour pressure-[kPa]\n", "vpW_14 = 1.60 ;\t\t\t#Vapour pressure-[kPa]\n", "n_F = (P_F*F)/(R*T_F) ;\t\t\t# Number of moles in F\n", "\n", "# Calculations\n", "# Material balance to calculate P & W\n", "P = (n_F*((P_F-vpW_30)/P_F))/((P_p-vpW_14)/P_p) ;\t\t\t# P from mat. bal. of air -[kg mol]\n", "W = (n_F*(vpW_30/P_F))- P*(vpW_14/P_p); \t\t\t# W from mat. bal. of water -[kg mol]\n", "iW = n_F*(vpW_30/P_F) ;\t\t\t# Initial amount of water -[kg mol]\n", "fr_con = W/iW ;\t\t\t#Fraction of water condenseed \n", "\n", "# Results\n", "print ' Fraction of water condenseed %.3f.'%fr_con\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ " Fraction of water condenseed 0.668.\n" ] } ], "prompt_number": 10 }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ " Example 17.5 Page no. 527\n" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Variables\n", "P = 100. ;\t\t\t# Pressure of air-[kPa]\n", "T = 20. + 273 ;\t\t\t# Temperature of air-[K]\n", "R = 8.314 ;\t\t\t# [(kPa*m**3)/(k mol*K)] \n", "EOH = 6 ;\t\t\t# Amount of ethyl alcohol to evaporate-[kg]\n", "mw_EOH = 46.07 ;\t\t\t# Mol.wt. of 1 k mol ethyl alcohol-[kg]\n", "\t\t\t\n", "# Calculations\n", "# Additional data needed\n", "vp_EOH = 5.93 ;\t\t\t# Partial pressure of alcohol at 20 C-[kPa]\n", "vp_air = P-vp_EOH ;\t\t\t# Partial pressure of air at 20 C-[kPa]\n", "n_EOH = EOH/mw_EOH ;\t\t\t#Moles of ethyl alcohol -[kg mol]\n", "n_air = (n_EOH*vp_air)/vp_EOH ;\t\t\t# Moles of air -[kg mol]\n", "V_air = n_air*R*T/P ;\t\t\t# Volume of air required\n", "\n", "# Results\n", "print ' Volume of air required to evaporate 6 kg of ethyl alcohol is %.1f cubic metre . '%V_air\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ " Volume of air required to evaporate 6 kg of ethyl alcohol is 50.3 cubic metre . \n" ] } ], "prompt_number": 11 }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ " Example 17.6 Page no. 529\n" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "# Variables\n", "P = 760. ;\t\t\t# Pressure -[ mm of Hg]\n", "vp = 40. ;\t\t\t# vapour pressure of n-heptane-[mm of Hg]\n", "\n", "# Calculations\n", "K = 10**((math.log10(vp/P)-0.16)/1.25) ;\n", "x = 0.5 ;\t\t\t# mole fraction after t_half\n", "x0 = 1. ;\t\t\t# initial mole fraction \n", "t_half = (math.log(x/x0))/(-K);\t\t\t# Time required to reduce the concentration to one-half-[min]\n", "\n", "# Results\n", "print 'Time required to reduce the concentration to one-half is %.1f min. '%t_half\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Time required to reduce the concentration to one-half is 9.8 min. \n" ] } ], "prompt_number": 12 }, { "cell_type": "code", "collapsed": true, "input": [], "language": "python", "metadata": {}, "outputs": [] } ], "metadata": {} } ] }