The target concentration Cref ramps down from 8.57 kmol/m^3 at t=10 to 2 kmol/m^3
at t=36 (the transition lasts 26 minutes). The corresponding profile Tref for the reactor
temperature is obtained by interpolating the equilibrium values TrEQ from trim analysis.
The controller computes the coolant temperature adjustment dTc relative to the initial
equilibrium value TcEQ(1)=297.98 for Cr=8.57. Note that the model is set up so that
initially, the output TrSP of the "Concentration controller" block matches the reactor
temperature, the adjustment dTc is zero, and the coolant temperature Tc is at its
equilibrium value TcEQ(1).
clf
t = [0 10:36 45];
C = interp1([0 10 36 45],[8.57 8.57 2 2],t);
subplot(211), plot(t,C), grid, set(gca,'ylim',[0 10])
title('Target residual concentration'), ylabel('Cref')
Gain-Scheduled Control of a Chemical Reactor