# Oneeq20a

 Name: Oneeq20a - Equilibrium conversion in a tubular reactor - original form Source: N. Brauner, M. Shacham and M. Cutlip, Chem. Eng. Educ., 30 (1), 20-25 (1996). Reference/s Model: 1 implicit equation, indep. variable name: xa High difficulty level Constraints: 0<=xa<=1 Discontinuities: function undefined for xa=1.029 Initial range: xamin=0.75, xamax=1.2 Solved by Shacham, M., POLYMATH 5.1, build 19, April 1, 2001 Model Eqs. Equilibrium conversion in a tubular reactor - original form |POLVER05_1 EXCEL FILE f(xa)=-ra/FA0 # TEXT FILE T=313 # POLYMATH FILE P0=10 # FA0=20*P0/(0.082*450) # k1=1.277*1.e9*exp(-90000/(8.31*T)) # k2=1.29*1.e11*exp(-135000/(8.31*T)) # den=1+7*P0*(1-xa)/(1+xa) # xa1=1+xa # ra = (-k1*P0*(1-xa)/xa1+k2*P0*P0*xa*xa/(xa1^2))/den # xa(min)=.75, xa(max)=1.2 Variable/function values Variable Value f(x) xa 0.85 2.69E-08 T 313 P0 10 FA0 5.420054201 k1 1.19915E-06 k2 3.71E-12 den 6.675675676 xa1 1.85 ra -1.45634E-07 Root Variable Value f(x) xa 0.999251497006000 7.9049E-10 T 313 P0 10 FA0 5.42005420054200 k1 1.1991500E-06 k2 3.7120483E-12 den 1.02620741295400 xa1 1.99925149700600 ra -4.2844995E-09 Additional information There is a scaling problem. Function value is very small throughout the entire range of interest (order of E-8). A point discontinuity very close to the root. Function plot