Question

develop a programming code in FORTRAN 77 software for solar assisted air source water heat pump inline connected with bry air dehumidifier and pulse tube cryocooler

Answer 1

"!Solving Chemical Equilibrium using the Law of Mass Action "

"Liquid octane at 300 K is reacted with 120% theoretical air also at 300 K. The reaction can be written:

C8H18 + a (O2+3.76N2) = b C02 + c CO + d H2O + e N2 + f O2 + g NO

Determine the temperature and composition of the equilibrium products which are at 5 bar.

This problem illustrates the use of the external procedure JANAF in a function and in a procedure."

procedure h&g(S$,T:h,g)
"This procedure uses the JANAF external procedure to return the enthalpy and Gibbs energy of species S$ at T."
   call JANAF(S$,T:cp,h,s)
   g:=h-T*s
end h_g

Function hf(S$,T)
"This function uses the JANAF external procedure to return the enthalpy of species S$ at T."
   Call JANAF(S$,T:cp,hf,s)
end hf

"Stoichiometry for a basis of 1 kgmole of octane"
8-b-c=0            "Carbon balance"
18-2*d=0            "Hydrogen balance"
2*a-2*b-c-d-2*f-g=0       "Oxygen balance"
a*3.76*2-2*e-g=0       "Nitrogen balance"
a_stoic=8+4.5       "no excess oxygen and complete combustion"
a=a_stoic*1.2           "120% theoretical air"  
P=5 [bar]            "specified pressure of productsr"
P_ref=1[bar]            "reference pressure for evaluation of standard state Gibbs energy"
R=R#             "Universal gas constant"

"Total moles of gas and mole fractions."
n_tot=(b+c+d+e+f+g)
y_CO2=b/n_tot; y_CO=c/n_tot; y_H2O=d/n_tot; y_N2=e/n_tot;; y_O2=f/n_tot; y_NO=g/n_tot

"The following equations provide the enthalpy and the specific Gibbs Free Energy for each chemical species at T and the reference pressure of 101.3 kPa. The JANAF external procedure is used in the Procedure h&g to calculate h and g at the equilibrium temperature, which is determined from an energy balance."
call h&g('CO2',T:h_CO2, g|o_CO2)
call h&g('CO',T:h_CO, g|o_CO)
call h&g('N2',T:h_N2, g|o_N2)
call h&g('O2',T:h_O2, g|o_O2)
call h&g('NO',T:h_NO, g|o_NO)
call h&g('H2O',T:h_H2O, g|o_H2O)

"Standard-state Gibbs Free Energy change for CO-CO2 and for N2-O2 reactions."
DELTAG|o_1=0.5*g|o_O2+g|o_CO-g|o_CO2
DELTAG|o_2=2*g|o_NO-g|o_O2-g|o_N2

"Law of Mass Action for reactions 1 and 2"
DELTAG|o_1=-R*T*ln(K_1)
DELTAG|o_2=-R*T*ln(K_2)

"Definition of equilibrium constant for reactions 1 and 2"
K_1=y_CO/y_CO2*(sqrt(y_O2*P/P_ref))   
K_2=y_NO^2/(y_O2*y_N2)

"Find the enthalpy of the reactants- liquid octane is not in the EES or JANAF data base."
h_f_C8H18=-249952       "[kJ/kmol] enthalpy of formation of liquid octane at 300 K."
h_f_O2=hf('O2',300)       "[kJ/kmol] enthalpy of O2 at 300 K"
h_f_N2=hf('N2',300)       "[kJ/kmol] enthalpy of N2 at 300 K"
HR=h_f_C8H18+a*h_f_O2+3.76*a*h_f_N2

"Find the enthalpy of products"
HP=b*h_CO2+c*h_CO+d*h_H2O+e*h_N2+f*h_O2+g*h_NO

"Apply an adiabatic energy balance to determine the product temperature"
HR=HP   

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