User`s guide

Time Delays
2-49
The regulated output variabl es are:
• Percentage of methanol in the distillate
• Percentage of methanol in the bottom products.
The goal is to maximize by adjusting the reflu x flo w rate an d the steam
flow rate in the reboiler.
To obtain a linearized model around the steady-state operating conditions, the
transi ent responses to pulses in steam and reflux flow are fitted by first-order
plus delay models. The resulting transfer function model is
Note the different time delays for each input/output pair.
You can specify this MIMO transfer function by typing
H = tf({12.8 –18.9;6.6 –19.4},...
{[16.7 1] [21 1];[10.9 1] [14.4 1]},...
'iodelay',[1 3;7 3],...
'inputname',{'R' , 'S'},...
'outputname',{'Xd' , 'Xb'})
X
D
X
B
X
D
R
S
X
D
s()
X
B
s()
12.8e
1s–
16.7e 1+
------------------------
18.9 e
3s–
–
21.0s 1+
-------------------------
6.6e
7s–
10.9s 1+
------------------------
19.4 e
3s–
–
14.4s 1+
-------------------------
Rs()
Ss()
=