I need help with a material balance problem.

FUNCTION:

function [A, B, C, D, E, F] = material_balance (Ao, Bo, Co, Do, Eo, Fo)

[A, B, C, D, E, F] = Ao+Bo+Co+Do+Eo+Fo

k21 =0.2;

k31 =0.1;

k32 =0.1;

k34 =0.1 ;

k54 =0.05;

k64 =0.2 ;

k12 =0.1 ;

k13 =0.05 ;

k23 =0.05;

k43 =0.2 ;

k45 =0.1;

k46 =0.2;

k65 =0.1;

k56 =0.1;

x = [ -(k21+k31) k12 k13 0 0 0

k31 k32 -(k13+k23+k43) k34 0 0

0 0 0 k54 -(k45-k65) k56

k21 -(k12+k32) k23 0 0 0

0 0 k43 -(k34+k54+k64) 0 k45

0 0 0 k64 k65 -(k46+k56)];

b = [0

0

0

0

0

0];

[A B C D E F]= inv(x)*b

SCRIPT:

clear, clc, close all

Ao =1.0;

Bo =0;

Co =0 ;

Do =0 ;

Eo =1.0;

Fo= 0;

[A, B, C, D, E, F] = material_balance (Ao, Bo, Co, Do, Eo, Fo)

Please Help!

[Nicole Jackson]

It's me again. The code is not working, I keep getting 0 as the answer for A, B, C, D, E, and F.

[Akira Agata]

It's an simultaneous ordinary differential equations. Please refer to the following ode45 documentation page.

https://www.mathworks.com/help/matlab/ref/ode45.html

[Torsten]

Do you try to calculate the steady state for your chemical system ?

[Nicole Jackson]

How do I calculate a steady state?

[Torsten]

You set the time derivatives to zero and solved

x*[A;B;C;D;E;F] = 0

But you are told to solve

x*[A;B;C;D;E;F] =[dA/dt;dB/dt;dC/dt;dD/dt;dE/dt;dF/dt].

Try an ODE integrator to do so, e.g. ODE15S.