Function ENTHALPY_O (T)

{$ENTHALPY_O

Enthaply of monatomic oxygen units kJ/kgmol}

a1=0.0254e2

a2=-0.02755e-3

a3=-0.03103e-7

a4=0.04551e-10

a5=-0.0455106e-14

a6=0.02923e6

ENTHALPY_O = 8.314*T*(a1+a2*T/2+a3*T^2/3+a4*T^3/4+a5*T^4/5+a6/T)

END

Function ENTROPY_O (T)

{$ENTROPY_O

Entropy of monatomic oxygen units kJ/kgmol-K}

a1=0.0254e2

a2=-0.02755e-3

a3=-0.03103e-7

a4=0.04551e-10

a5=-0.0455106e-14

a7=0.04920e2

ENTROPY_O = 8.314*(a1*ln(T)+a2*T+a3*T^2/2+a4*T^3/3+a5*T^4/4+a7)

END

Function ENTHALPY_OH (T)

{$ENTHALPY_OH

Enthaply of OH units kJ/kgmol}

a1=0.02883e2

a2=0.101397e-2

a3=-0.022769e-5

a4=0.021747e-9

a5=-0.051263e-14

a6=0.038869e5

ENTHALPY_OH = 8.314*T*(a1+a2*T/2+a3*T^2/3+a4*T^3/4+a5*T^4/5+a6/T)

END

Function ENTROPY_OH (T)

{$ENTROPY_OH

Entropy of OH units kJ/kgmol-K}

a1=0.02883e2

a2=0.101397e-2

a3=-0.022769e-5

a4=0.021747e-9

a5=-0.051263e-14

a7=0.055957e2

ENTROPY_OH = 8.314*(a1*ln(T)+a2*T+a3*T^2/2+a4*T^3/3+a5*T^4/4+a7)

END

Function ENTHALPY_H (T)

{$ENTHALPY_H

Enthaply of monatomic hydrogen units kJ/kgmol}

a1=0.025e2

a2=0

a3=0

a4=0

a5=0

a6=0.02547e6

ENTHALPY_H = 8.314*T*(a1+a2*T/2+a3*T^2/3+a4*T^3/4+a5*T^4/5+a6/T)

END

Function ENTROPY_H (T)

{$ENTROPY_H

Entropy of monatomic hydrogen units kJ/kgmol-K}

a1=0.025e2

a2=0

a3=0

a4=0

a5=0

a7=-0.04601e1

ENTROPY_H = 8.314*(a1*ln(T)+a2*T+a3*T^2/2+a4*T^3/3+a5*T^4/4+a7)

END

P1=101.3 {kpa}

P=1000/101.3 {atm}

R=8.314 {kJ/kmol-K}

{ Reaction:

a (C3H8 +5/Phi(O2 + 3.76 N2)) + b(3 CO2 + 4 H2O +0.26 O2 + 19.76 N2) -->

3(a+b) CO2 + 4(a+b) H2O + 0.26(a+b) O2 + 19.76(a+b) N2 }

26.06*a+27.06*b=1 {1 total mole of reactants }

X_res=27.06*b {residual mole fraction - note there is one total mole of reactants}

hc3=Enthalpy(C3H8, T=298)

hco2=Enthalpy(CO2, T=T1)

hh2o=Enthalpy(H2O, T=T1)

ho2=Enthalpy(O2, T=T1)

hn2=Enthalpy(N2, T=T1)

{T1 is the product temperature

H_reactants = H_products }

a*hc3+3*b*Enthalpy(CO2,T=298)+4*b*Enthalpy(H2O,T=298)=(a+b)*(3*hco2+4*hh2o+0.26*ho2+19.8*hn2)

{Equilibrium calculation - note P1 = reference pressure = 101.3 kPa = 1 atm}

go2=Enthalpy(O2,T=T1)-T1*Entropy(O2,T=T1,P=P1)

go=ENTHALPY_O(T1)-T1*ENTROPY_O(T1)

gn2=Enthalpy(N2,T=T1)-T1*Entropy(N2,T=T1,P=P1)

gno=Enthalpy(NO,T=T1)-T1*Entropy(NO,T=T1,P=P1)

goh=ENTHALPY_OH(T1)-T1*ENTROPY_OH(T1)

gh2o=Enthalpy(H2O,T=T1)-T1*Entropy(H2O,T=T1,P=P1)

gh=ENTHALPY_H(T1)-T1*ENTROPY_H(T1)

3*(a+b)=nco2 {C balance }

8*(a+b)=2*nh2o+noh+nh {H balance}

(2*0.26+4+6)*(a+b)=2*nco2+nh2o+2*no2+no+noh+nno {O balance}

19.8*(a+b)=2*nn2+nno {N balance}

ntot=nco2+nh2o+no2+nn2+nno+no+noh+nh

{

O2 -> 2O Equilibruim

}

kpo=exp(-(2*go-go2)/R/T1)

kpo=no^2/no2 * (P/ntot)

{

N2 + O2 = 2NO Equilibrium

}

kpno=exp(-(2*gno-gn2-go2)/R/T1)

kpno=nno^2/nn2/no2

{

H2O +1/2 O2 = 2OH Equilibrium

}

kpoh=exp(-(2*goh-gh2o-0.5*go2)/R/T1)

kpoh=noh^2/nh2o/sqrt(no2) * (P/ntot)^0.5

{

H2O = OH + H Equilibrium

}

kph=exp(-(goh+gh-gh2o)/R/T1)

kph=noh*nh/nh2o * (P/ntot)

{Conversion to concentrations }

C_O=no*P*101.3/(ntot*R*T1) {kmol/m^3}

C_OH=noh*P*101.3/(ntot*R*T1)

C_H=nh*P*101.3/(ntot*R*T1)

C_NO=nno*P*101.3/(ntot*R*T1)

C_O2=no2*P*101.3/(ntot*R*T1)

C_N2=nn2*P*101.3/(ntot*R*T1)

xno=nno/ntot*1e6 {NO in parts per million}