The simulink block for the FCCU obtainable from
cpc_fcc.mdl is to be used for development of transfer
is to be used for development of transfer function models between
the outputs and the inputs of the process. The specifications
for the process are given below:
Inputs (Manipulated variables)
Regenerated catalyst feed rate (Fs) : steady state value = 294 kg/s
Air flow rate (Fa) : steady state value = 25.35 kg/s
Riser outlet temperature (T1) : steady state value = 776.9 K
Regenerator cyclone temperature (Tcy) : steady state value = 988.1 K
Regenerator bed temperature (Trg) : steady state value = 965.4
You should attempt to develop transfer functions between each
of the inputs and the outputs, i.e. six transfer functions in
all. The control problem involves the control of two outputs by manipulating
the two inputs. Suggested outputs for control are T1 and Tcy.
Trg should also be monitored during the control phase of the project. For
SISO control, develop four controllers based on input-output combinations
with T1 and Tcy being the controlled outputs, and Fs and Fa being the manipulated
variables. Each controller will be run on the plant in isolation.
You will develop transfer functions by running step tests, one
input at a time, and observing the output responses. You will
then attempt to fit the observed response to a transfer function
model, and comment on the goodness of fit. Note that the step
inputs in the simulink file have initial values set at steady
state values, so that you will have to input the final values
of the steps in physical variables (and not deviation variables).
This is because the simulink block has been set up to accept inputs
in physical variables. Outputs are also available as physical
The simulink block has measurement noise built into it, so that
you will obtain a noisy response to your step inputs. In order
to maintain a reasonable ratio of the true value to the magnitude
of the noise for the output responses, it is recommended that
you use a step of magnitude 10 kg/s for the input Fs (regenerated
catalyst flow rate) and a step of magnitude 1 kg/s for the input Fa
(air flow rate).
The next step is to design SISO controllers for each input-output combination
(T1 controlled by manipulating Fs, T1 controlled by manipulating Fa, Tcy
controlled by manipulating Fs, Tcy controlled by manipulating Fa). Implement
these SISO controllers one at a time on the plant, and run simulations for
setpoint changes of the order of 10 degrees C.
Submissions for this stage of the project must include the transfer functions you develop, and plots of all the output step responses (the actual plant responses and your model's fit). Be sure to specify the magnitude of the step in the input (especially if it is not a unit step) for each case.Also present results for control with all four SISO controllers. For the control results, be sure to include plots of the uncontrolled output along with the plots of the controlled output and the manipulated variable. Attach a memo with your work consisting of a description of the procedure you followed for model development and controller design, and a discussion of your results.