
Development of an Activated Carbon Fiber Cloth Adsorption/Regeneration System to Recover and Reuse Toxic Volatile Organic Compounds |
APPENDIX D Mass Transfer/Thermodynamic Model
{mass balance}
mLdot=Kg*MWA*(dPlmAC)*area1
m1dot=m2dot-mLdot
m2dot=rhoAN2*QAN2
{Wagner Equation}
Pa2=xA2*P
xA1=xA2-(mLdot/m2dot)*(MWTA1/MWA)
Pa1=xA1*P
Pc=((exp(((-7.45514*J7)+(1.202*(J7^1.5))+(-2.43926*(J7^3))+(-3.3559*(J7^6)))/(Tc/508.1))*47))* 1e5
J7=1-(Tc/508.1)
{Thermodynamic Balance}
mLNdot*hLN+mLNdot*EnthN1=mLdot*hA+mLdot*EnthL+(rhoAN1*QAN1)*EnthAN
{Mass Transfer}
dPlmAC=((Pa2-Pc)-(Pa1-Pc))/ln((Pa2-Pc)/(Pa1-Pc))
Pa2n=Pa2-(1e-10)
xA2n=xA2-(1e-10)
Kg=(h1*((CpAN*VisAN/kAN)^(2/3)))/((CpAN*Pngf*MWANave)*(((VisAN/(rhoANave*kd))^(2/3))))
Pcn=Pc+(.001)
Kg=(h1*((CpAN*VisAN/kAN)^(2/3)))/((CpAN*Pngf*MWANave)*(((VisAN/(rhoANave*kd))^(2/3))))
kd=((0.0166*(((TA1+TA2)/2)^(3/2))*((1/MWN+1/MWA)^(1/2)))/((P/101325)*(NuN^(1/3)+
NuA^(1/3))^(2)){ft^2/hr}*0.0929/3600){m^2/sec}
Pngf=(PNc-PNb)/(ln(PNc/PNb))
PNc=P-Pc
PNb=P-((Pa1+Pa2)/2)
h1=1.86*(kAN/De)*((De*Gave/VisAN)*(CpAN*VisAN/kAN)*(De/dx))^(1/3)*(VisAN/VisANc)^(0.14)
{Correlations}
area1=3.14159*De*dx
area2=3.14159*Din*dx
area3=(3.14159*De^2)/4
MWANave=((MWTA1+MWTA2)/2)
rhoANave=((rhoAN1+rhoAN2)/2)
Gave=(rhoAN1*QAN1+rhoAN2*QAN2)/(2*area3)
De=(Dout^2-Din^2)/Din {m}
rhoAN1=P*MWTA1/(R*TA1)
rhoAN2=P*MWTA2/(R*TA2)
QAN1=m1dot/rhoAN1
MWTA1=xA1*MWA+xN1*MWN
MWTA2=xA2*MWA+xN2*MWN
xA1+xN1=1
xA2+xN2=1
{Specific Heats}
CpN2=(31.2+-0.0136*(TaveN2)+0.0000268*(TaveN2)^2+-0.0000000117*(TaveN2)^3)*(1/MWN) *(1000)
TaveN2=(TA1+TA2)/2
CpA=(6.301+0.261*TaveA-0.000125*(TaveA)^2+0.0000000204*(TaveA)^3)*(1/MWA)*(1000)
TaveA=(TA1+TA2)/2
CpAN=((xA1+xA2)/2)*CpA+((xN1+xN2)/2)*CpN2
CpL=(2.3388-0.0038942*Tc+1.1221e-05*(Tc)^2)*1000 {J/kg K} {correlation with experimental data}
{Enthalpies -- Integrated form of Specific Heats}
EnthN1=(31.2*(TN2-TN1)+-0.0136/2 * (TN2^2-TN1^2)^2+0.0000268 /3* (TN2^3-TN1^3)+ -0.0000000117/4*(TN2^4-TN1^4)) *(1/MWN)*(1000) {g-mol/kg-mol}
EnthN2=(31.2*(TA2-TA1)+-0.0136/2*(TA2^2-TA1^2)+0.0000268/3*(TA2^3-TA1^3)+ -0.0000000117/4*(TA2^4-TA1^4)) *(1/MWN)*(1000) {Reid 226}
EnthL=(2.3388*(TA2-TA1)-0.0038942/2*(TA2^2-TA1^2)+1.1221e-05/3*(TA2^3-TA1^3))*1000 {J/kg K} {correlation with experimental data}
EnthA=(6.301*(TA2-TA1)+0.261/2*(TA2^2-TA1^2)-0.000125/3*(TA2^3-TA1^3)+ 0.0000000204/4*(TA2^4-TA1^4))*(1/MWA)*(1000)
EnthAN=((xA1+xA2)/2)*EnthA+((xN1+xN2)/2)*EnthN2
{Viscosities}
{N2 Gas--Chapman-Enskog Method: Non-polar gas}
{Inner Tube}
sigmaN=3.798 {Ang.}
epskN=71.4 {K} {potential energy constant-epsilon/boltzmann's constant}
AAN=1.16145
BBN=0.14874
CCN=0.52487
DDN=0.77320
EEN=2.16178
FFN=2.43787
{Outer Tube}
VisNGO=26.69*(MWN*TaveN2)^(1/2)/(sigmaN^2*OMEGAvNO) {micro Poise}
OMEGAvNO=AAN/(TstarNO^(BBN))+CCN/(exp(DDN*TstarNO))+EEN/(exp(FFN*TstarNO))
TstarNO=TaveN2/epskN
{Outer Tube at Condensate Film}
VisNGOc=26.69*(MWN*Tc)^(1/2)/(sigmaN^2*OMEGAvNOc) {micro Poise}
OMEGAvNOc=AAN/(TstarNOc^(BBN))+CCN/(exp(DDN*TstarNOc))+EEN/(exp(FFN*TstarNOc))
TstarNOc=Tc/epskN
{Acetone Gas Viscosity--Reichenberg Method: Polar Gas}
VisAce=(Astar*(TrAce)/((1+0.36*TrAce*(TrAce-1))^(1/6)))
TrAce=TaveN2/508.1
Astar=MWA^(1/2)*508.1/(30.1) {30.1 from molecular bond structure of Acetone--see notes}
{Acetone Gas Viscosity at Condensate Film--Reichenberg Method: Polar Gas}
VisAcec=(Astar*(TrAc)/((1+0.36*TrAc*(TrAc-1))^(1/6)))
TrAc=Tc/508.1
{Combined Gas Viscosity--Brokaw Approximation of PHIij}
VisAN=((xAave*VisAce/(xAave+xNave*PHI12))+(xNave*VisNGO/(xNave+xAave*PHI21)))*1e-7
xAave=(xA1+xA2)/2
xNave=(xN1+xN2)/2
PHI12=(VisAce/VisNGO)^(1/2)*Souter12*Aouter12
Aouter12=mwx12*MWy12^(-1/2)*(1+((MWy12-MWy12^(0.45)))/(2*(1+MWy12)+((1+MWy12^(0.45))*mwx12^(-1/2)/(1+mwx12))))
mwx12=(4/((1+MWy12^(-1))*(1+MWy12)))^(0.25)
MWy12=MWA/MWN
PHI21=(VisNGO/VisAce)^(1/2)*Souter21*Aouter21
Souter21=Souter12
Aouter21=(MWN/MWA)^(-0.37) {since 0.4 < (MWN/MWA) < 1.33}
Souter12=(1+(TstarAce*TstarNO)^(1/2))/(((1+TstarAce+deltaAce^2/4)^(1/2))*((1+TstarNO)^(1/2)))
TstarAce=TaveA/epskA
epskA=560.2 {K}
deltaAce=(1.94e03*dipoleAce^2)/(VboilingA*TboilingA)
dipoleAce=2.9 {debyes}
VboilingA=82.6 {cm3/g-mol}
TboilingA=329.4 {K}
TboilingN=77.4 {K}
{Combined Gas Viscosity at Condensate Film--Brokaw Approximation of PHIij}
VisANc=((xAc*VisAcec/(xAc+xNc*PHI12c))+(xNc*VisNGOc/(xNc+xAc*PHI21c)))*1e-7
xAc=(Pc/P)
xNc=(1-Pc/P)
PHI12c=(VisAcec/VisNGOc)^(1/2)*Souter12c*Aouter12
PHI21c=(VisNGOc/VisAcec)^(1/2)*Souter21c*Aouter21
Souter21c=Souter12c
Souter12c=(1+(TstarAc*TstarNc)^(1/2))/(((1+TstarAc+deltaAce^2/4)^(1/2))*((1+TstarNc)^(1/2)))
TstarAc=Tc/epskA
TstarNc=Tc/epskN
{Conductivity of Acetone Gas}
kAce=(TaveA/TrefA)^(1.786)*kAceref
TrefA=373 {K}
kAceref=17.3e-3 {W/m K}
{Conductivity of Gas Mixture--Wassiljewa Eq. modified with the Lindsay and Bromley Modification}
kAN=(xAave*kAce/(xAave+Ak12*xNave))+(xNave*kNG2/(xNave+Ak21*xAave))
Ak12=(1/4)*(1+(VisAce*1e7/(VisNGO*1e7)*((MWN/MWA)^(3/4))*(TaveA+Sace) /(TaveA+Snit))^(1/2))^2*(TaveA+Sacenit)/(TaveA+Sace)
Ak21=(1/4)*(1+(VisNGO*1e7/(VisAce*1e7)*((MWA/MWN)^(3/4))*(TaveA+Snit) /(TaveA+Sace))^(1/2))^2*(TaveA+Sacenit)/(TaveA+Snit)
Sace=1.5*TboilingA
Snit=1.5*TboilingN
Sacenit=Cs*((Sace*Snit)^(1/2))
Cs=0.73 {If one of the gases is very polar, otherwise-->Cs=1.0}
{Parameters}
{dx=.1}
Dout=0.0191 {m}
Din=0.0127 {m}
P=101325 {N/m^2}
R=8314 {N m/K kg-mol}
TA2=294.1 {K}
TA1=200 {K}
T1=77 {K}
MWA=58.1 {kg/kg-mol}
MWN=28.02 {kg/kg-mol}
NuN=2*15.6 {2*N}
NuA=3*14.8+6*3.7+7.4 {3*C+6*H+O}
QAN2=(1{Lpm}/(1000*60)) {m3/sec}
xA2=0.8
kNG2=1.8e-2
hA=524000*((1-Tc/508.1)/(1-329.2/508.1))^0.27 {J/Kg}{Reid pg.228}
hLN=199106 {J/Kg}
mLNdot=0.00001667 {Kg/sec}