From b1f5c3f8d6671b4331cef1dcebdf63b7a43a3a2b Mon Sep 17 00:00:00 2001 From: priyanka Date: Wed, 24 Jun 2015 15:03:17 +0530 Subject: initial commit / add all books --- 1040/CH7/EX7.6/Ex7_6.sce | 148 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 148 insertions(+) create mode 100644 1040/CH7/EX7.6/Ex7_6.sce (limited to '1040/CH7/EX7.6/Ex7_6.sce') diff --git a/1040/CH7/EX7.6/Ex7_6.sce b/1040/CH7/EX7.6/Ex7_6.sce new file mode 100644 index 000000000..46631e743 --- /dev/null +++ b/1040/CH7/EX7.6/Ex7_6.sce @@ -0,0 +1,148 @@ +//Harriot P,2003,Chemical Reactor Design (I-Edition) Marcel Dekker,Inc., USA,pp 436. +//Chapter-7 Ex7.6 Pg No.300 +//Title:Fraction of O2,Power of agitator, k_L_a and average dissolved oxygen concentration. +//====================================================================================================================== +clear +clc +// COMMON INPUT +Vol_reactor=200;//Volume of reactor (m3) +D=4;//Diameter of reactor (m) +depth=12;//Depth of reactor (m) +u_g=3;//Superficial velocity (cm/sec) +T_C=30;//Temperature (°C) +T_K=273+T_C;//Temperature (K) +f_O2=0.21;//Fraction of O2 in air +myu_soln=1.5*(10^(-3));//Viscosity of solution (Pa sec) +R=0.08206;//Gas constant (m3 atm/ K kmol) +r_O2_peak=45*(10^(-3));//Flow rate of O2 at peak demand +Da_by_Dt=(1/3); +Da=1.333;//(m) +N=120;//(rpm) +N_conv=(N/60);//(sec-1) +Press_top=1;//Pressure at the top of the vessel (atm) +rho=1000;//Density of water (kg/m3) +ug_sup1=3*(10^(-2));//based on 30(°C) and 1 (atm) +V=151;//Volume of solution calculated Ex7.6.a (m3) +ug_sup1=3*(10^(-2));//based on 30(°C) and 1 atm. +Press_top=1;//Pressure at the top of the vessel (atm) +Press_bottom=2;//From Ex7.6.c +ug_sup2=ug_sup1/Press_bottom;// at 2atm superficial velocity (cm/sec) +ug_ave=(ug_sup1+ug_sup2)/2;//Average superficial velocity (cm/sec) +depth=12;//Depth of reactor (m) +one_atm_water=10.3;//1 atm pressure corresponds to 10.3 (m) height of water +k_H_O2=5.2*10^(4)// Henery's law constant for O2 in water for O2 (atm/mol fraction) +M_O2=32;//Molecular weight of O2 +M_H2O=18;//Molecular weight of water +C_O2_critical=1*10^(-3);//Critical O2 Concentration (g/L) +percent_reduction=40/100;//Mass transfer coefficient in the upper region of the reactor is 40% less than the average +kLa_soln=0.22;//Value calculated in Ex7.6.d +r_conv=1.25*10^(-5);//Rate at peak O2 demand (mol/L sec) +depth=12;//Depth of reactor (m) + + +//CALCULATION (Ex7.6.a ) +S=%pi*(D^2)/4;//Cross section area (m2) +V=S*depth;//Volume of solution(m3) +F_air=(S*u_g*(10^(-2))*3600)/(R*(10^(-3))*T_K); +F_O2=f_O2*F_air;//Feed rate of O2 (mol/hr) +F_O2_used=r_O2_peak*V*(10^(3));//O2 used for aerobic fermentation (mol/hr) +F_O2_left=F_O2-F_O2_used;//O2 left after aerobic fermentation(mol/hr) +f_O2_exitgas=F_O2_left/F_air;//Fraction of O2 in exit gas +Percent_O2_exitgas=(f_O2_exitgas)*(100); +Frac_O2_used=((f_O2-f_O2_exitgas)/f_O2); + +//CALCULATION (Ex7.6.b ) +Re=(rho*N_conv*Da^2)/myu_soln; +N_p=6;//For a standard turbine +N_p_pitched=1.7;//For a pitched-blade turbine +P0=(N_p*rho*(N_conv^3)*(Da^5))*(10^(-3));//Refer equation 7.73 (kW) +//If the turbine is 2 m from the bottom, or 10 m below the surface,the pressure is about 2 atm since 1atm= 10.3 m water +Press_bottom=2 +ug_sup2=ug_sup1/Press_bottom; +Q=ug_sup2*S; +N_Ae=Q/(N_conv*(Da^3)); +Pg_by_P0=0.55;//From figure 7.15 based on N_Ae value calculated +Pg=Pg_by_P0*P0;//When aerated +P0_pitched=(N_p_pitched/N_p)*P0; +Pg_by_P0_pitched=0.8;//Solution reaching the upper stirrers is already aerated +Pg_pitched=Pg_by_P0_pitched*P0_pitched; +Tot_Pow_no_air=P0+Press_bottom*P0_pitched;//Total power when no air is presented +Tot_Pow_aerated=Pg+Press_bottom*Pg_pitched;//Total power when it is aerated + +//CALCULATION (Ex7.6.c ) +P_by_V_ave=Tot_Pow_aerated/V; +kLa_O2_sulfite=0.32;//Using figure7.16 based on ave(P/V) value and ug_average value +kLa_soln=0.7*kLa_O2_sulfite;//kLa for this solution is 70% of the value for oxygen absorption in sodium sulfite (sec-1) +y_O2=0.086;//If gas is backmixed +depth_ave=depth/2; +Press_ave=(Press_top+(depth_ave/one_atm_water));//Pressure at average depth (atm) +C_O2_star=(Press_ave*y_O2/k_H_O2)*(1000/M_H2O);//Conversion (mol/L) +r_conv=r_O2_peak/3600;//Rate at peak O2 demand (mol/L sec) +C_ave=(C_O2_star-(r_conv/kLa_soln)) +C_ave_conv=C_ave*M_O2*1000;//Converted value of O2 concentration in(mg/L) + +//CALCULATION (Ex7.6.d) +depth_ave=depth/2; +Press_ave=(Press_top+(depth_ave/one_atm_water));//Pressure at average depth (atm) +kLa_soln_reduced=kLa_soln*(1-percent_reduction); +C_star_minus_C=r_conv/kLa_soln_reduced; +C_O2_new=(C_O2_star-(C_star_minus_C)); +C_O2_new_conv=C_O2_new*M_O2*1000;//Converted value of O2 concentration in(mg/L) +C_O2_star_new=C_O2_star/Press_ave; + +//OUTPUT (Ex7.6.a) +mprintf('\n OUTPUT Ex7.6.a'); +mprintf('\n=========================================================='); +mprintf('\nAt the peak demand, fraction of the oxygen supplied = %.3f ',Frac_O2_used); + +//OUTPUT(Ex7.6.b ) +mprintf('\n\n\n OUTPUT Ex7.6.b'); +mprintf('\n=========================================================='); +mprintf('\nThe total power required for the agitator before the air is turned on: %0.0f kW',Tot_Pow_no_air); +mprintf('\nThe total power required for the agitator after the air is turned on: %0.0f kW',Tot_Pow_aerated); + +//OUTPUT (Ex7.6.c ) +mprintf('\n\n\n OUTPUT Ex7.6.c'); +mprintf('\n=========================================================='); +mprintf('\nThe calculated value of kLa (mass transfer coefficient) of solution:%0.2f (sec-1)',kLa_soln); +mprintf('\nThe calculated value of average dissolved O2 concentration: %0.2f (mg/L)',C_ave_conv); + + //OUTPUT (Ex7.6.d) + mprintf('\n\n\n OUTPUT Ex7.6.d'); +mprintf('\n=========================================================='); + mprintf('\nThe new calculated value of average dissolved O2 concentration %0.2f (mg/L)',C_O2_new_conv); + if(C_star_minus_C>C_O2_star_new) + mprintf('\nThe reactor is operated above critical O2 concentration '); + else + mprintf('\nThe reactor should be operated at higher air rate otherwise C_O2 would drop to zero') + end + // FILE OUTPUT +fid= mopen('.\Chapter7-Ex6-Output.txt','w'); +mfprintf(fid,'\n OUTPUT Ex7.6.a'); +mfprintf(fid,'\n=========================================================='); +mfprintf(fid,'\nAt the peak demand, fraction of the oxygen supplied = %.3f ',Frac_O2_used); +mfprintf(fid,'\n\n\n OUTPUT Ex7.6.b'); +mfprintf(fid,'\n=========================================================='); +mfprintf(fid,'\nThe total power required for the agitator before the air is turned on: %0.0f kW',Tot_Pow_no_air); +mfprintf(fid,'\nThe total power required for the agitator after the air is turned on: %0.0f kW',Tot_Pow_aerated); +mfprintf(fid,'\n\n\n OUTPUT Ex7.6.c'); +mfprintf(fid,'\n=========================================================='); +mfprintf(fid,'\nThe calculated value of kLa (mass transfer coefficient) of solution:%0.2f (sec-1)',kLa_soln); +mfprintf(fid,'\nThe calculated value of average dissolved O2 concentration: %0.2f (mg/L)',C_ave_conv); +mfprintf(fid,'\n\n\n OUTPUT Ex7.6.d'); +mfprintf(fid,'\n=========================================================='); +mfprintf(fid,'\nThe new calculated value of average dissolved O2 concentration %0.2f (mg/L)',C_O2_new_conv); + if(C_star_minus_C>C_O2_star_new) + mfprintf(fid,'\nThe reactor is operated above critical O2 concentration '); + else + mfprintf(fid,'\nThe reactor should be operated at higher air rate otherwise C_O2 would drop to zero') + end + mclose(fid); +//===================================================END OF PROGRAM====================================================== + + + + + + + -- cgit