ROTARY LIME KILN MODEL DEVELOPMENT

The two MATLAB files which you will need to simulate the rotary lime kiln are cpc_kiln.mdl and kiln_code.m. You will need to put both of these files in your own directory before using them. These files make-up a "plant" which you will apply step tests to in order to construct transfer-function models between its outputs and inputs. Note that you will only run the file cpc_kiln.mdl (in SIMULINK), but you need to have the file kiln_code.m present in the same directory in order to be able to run it. You will not directly run the file kiln_code.m.

The specifications for the process are given below:

Inputs (Manipulated variables)

fuel gas valve position (Fg) : steady state value = 0.5 (fraction open)

damper position (Dp) : steady state value = 0.5 (fraction open)

Measured Outputs

"Front end" (i.e. hot gas entrance) temperature (Th) : steady state value approximately = 2225 deg C

"Back end" (i.e. cold gas exit) temperature (Tc) : steady state value approximately = 425 deg C

The time scale for this plant is minutes.

You should attempt to develop transfer functions between each of the inputs and the outputs, that is, four transfer functions in all. The problem of control, which will be dealt with at a later stage, will involve the control of two outputs by correctly manipulating both inputs.

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 inputs to the simulink block both need to have initial values of 0.5, so that you will have to make your steps away from 0.5 toward 0.0 or 1.0. You may do this by staying in physical variables and making sure that you have initial step values of 0.5, or by subracting off the steady-state values and using steps in deviation variables. The outputs are provided as physical variables and since we are not doing any control at this point there is no need to be concerned about their deviation-variable forms. Note that the simulink block has measurement noise built into it, so that you will obtain a noisy response to your step inputs.

IMPORTANT SIMULATION DETAIL: For your simulations, you must use the Euler method of integration with a fixed (i.e. maximum=minimum) integration step size of 0.2.

Submissions for this stage of the project must include the transfer functions you develop and plots of both step inputs and the output responses. Attach a memo (a real memo, like one you'd give to someone signing your paychecks!) with your work consisting of a description of the procedure you followed for model development, and a discussion of your results. You may also include a discussion on any other issues you may consider important. For example, what happens if you try to push the simulation past the "physical" bounds of the problem? Do the results make sense? Why or why not?