model toolbox for a continuous Dual Vessel Hydraulic EMCC
digester, using Matlab® v6.1.
IETek, February 2002.
Fundamental dynamic plug flow model of dual vessel hydraulic
EMCC digester. Complex unit operation with moving packed bed of polydispersed
porous chips reacting with diffused entrapped liquor while moving through
co-current and counter-current liquor streams. High dimensional nonlinear
realistic dynamic model with great potential to be used as a reference toolbox
for a range of systems R&D work.
Chip movement through the vessels as individual discrete plugs
(about 1000 plugs in the vessels at any given time). Each chip plug carries its
own physical properties and reaction parameters. The model is naturally suited
for specie swing (transition) management and control.
Five different chip dimensions represent chip size variability
with interchip density (composition) gradients as part of the model.
Dynamic chip column compaction, one of the main sources of
Cinematic numerical approach to facilitate the solution of
~130,000 ODEs at a speed approximately 200 times faster than real time on a
1.7GHz PC; e.g., 5 minutes of real time in about 1.5 seconds including update of
Rich animated GUI for user
interactions and process visualization.
Although the toolbox code
represents hypothetical design and operating conditions, recently IETek has
successfully customized the model to simulate an operating commercial unit.
demonstration software retains most but not all of the capabilities available in
the full version of the software. In particular, the demo program is a compiled
executable code with no user m-file accessible input/output information. All of
the user interactions with the Demo code are through a GUI. The Demo software
highlights the essential features of the model and hopefully provides sufficient
information to a potential user to assess the value of the model for academic
research and development. Demo code consists of the following components: (1) rundvhemcc2002,
the executable compiled code (~2.1 megs); (2) FigureMenuBar and FigureToolBar,
two Matlab figure files to provide figure generating support to the executable
code (~100 kb combined); and (3) Data01, Matlab data file (mat)
containing the initial states for the model (~10 megs). Although the demo code
is in compiled form, the user still needs a valid Matlab license to run the
model. Under special arrangements IETek may provide a true standalone version of
the demo and the full code that would not require the presence of Matlab
software. Contact IETek (firstname.lastname@example.org)
to receive a free 30-day examination copy of the demo
code. Recommended environment for the code are: (a) ability to receive ~10 meg
through e-mail, (b) Matlab v6.1, (c) 252+ meg ram, and (d) XGA (1024x768) or
Install all 4 files into a project folder as a Matlab
application. Make sure that Matlab path has access to this folder. If the same
folder has other Matlab applications, then place the two figure files in a
subfolder called Bin to make sure that they do not interfere with other
m-file applications. Create a backup copy of the data file Data01 under a
different name so that you can always recover the original version. The code
always expects the data file to be under the default name Data01.
Start the model by typing !rundvhemcc2002 at the Matlab
prompt >> in the Command Window. The ! mark identifies the code as
compiled rather than the usual m-file.
Use the START button on the GUI to initiate a simulation
session. Use the manual interaction “triangles” to move process inputs up or
down. Explore other options of interacting with the model as instructed on the
GUI. Experiment with the two different choices for level control (through
OPTIONS button) and run through a demo of specie swing from softwood to
hardwood. Note that some trend graphs have multiple display options and each
dynamic trend or profile can be captured as a snapshot Matlab figure with a time
stamp. Try saving the states of a simulation (after a PAUSE or at the end) and
then restarting from that condition again. Note that saving the present states
as Data01 will overwrite the previous data file, and that the default
starting file name is Data01. Take advantage of the Data02 file
name that is offered as a safe intermediate storage location.
Chip level controls and specie swing (transition) feedforward
control policies are very rudimentary and provided for the sole purpose of
exercising/displaying model capabilities.
Contact IETek for questions, suggestions and bug reports, and to purchase the full code.
In the full version of the
software the user has complete m-file access to model inputs and outputs at
every time increment (5min) with the option of providing custom control and
process management policies. Initially the model starts operating from nominal
conditions as provided, but then can be taken to any other operating state
desired by the user. The model has the capability of “warm” starting from
any feasible operating state. This makes it possible for the user to either
terminate the model at any time and save the current results as the initial
conditions for a subsequent run, or pause the model to make manual changes in
the user input m-file (e.g. change controller tuning) before continuing with the
run. GUI provides animated visualization of the process conditions, live manual
input/interaction capabilities and graphical snapshot capturing of operating
status. User starts the code execution through an open m-file called rundvhemcc2002
which has defined option parameters selecting the way the user wants to the
model. For example, GUI may or may not be activated and the specific m-file name
for user decisions (Options.InputFileName) can be specified for single or
multiple applications. Within Options.InputFileName (default
inputspecifications_dvhemcc02 is provided) the user has complete
freedom to update decisions on process control and feed (chip and liquor)
properties. Alternatively, part or all of the process input decisions can be
made “live” from the animated GUI as demonstrated by the Demo Code. For
convenience, a separate file called outputprocessing_dvhemcc02 is
preserved for processing model outputs at each time increment. All pertinent
model variables and profiles are updated and available to the user as a snapshot
at current time as well as 24 hr history files at 5 minute frequency. The
specifics of the variable names and array sizes are defined in a user m-file
called inputoutputdefs_dvhemcc02. All other model computations and GUI
management tasks are done behind the curtain through pre-parsed Matlab p-files.
The model works for a fixed geometry hypothetical EMCC dual vessel design with a
wide range of operating capability. Both softwood and hardwood chip chemical and
physical properties are made available and nominal operating starting data files
for each specie are provided with the code. The full version of the code is
licensed to an organization, specific to one Matlab license (Matlab license
number required at the time of order), with a one-time fee of US$1,000 for
internal R&D use only. IETek will provide 12-month upgrade and bug fix
service free of charge. Other license arrangements and custom
modification/development options can be provided on a case-by-case basis. Please
contact IETek if you have questions or would like to place an order.
Modeling and numerical procedures
are based on the traditional fundamental conservation laws combined with
best-known data and information pertaining to the process. Every effort is made
to provide error free coding of the model, though it is entirely possible that
some bugs may still be hiding undetected in the details of the software. Please
notify IETek of any software bug discovered. A few words of caution here: (a)
the model represents a nonlinear process and you may easily perceive an
unexpected dynamic behavior as a possible bug, but the chances are there is a
physical/chemical reason for it; (b) this is a plug flow reactor model with
discretised numerical approximations, therefore almost no dynamic response is
smooth as it is usually with CSTR models, thus sharp local variations are
natural in this model. Therefore, plan for smooth and judicious control actions
as it is actually practiced with the real process. Some operating restrictions
are imposed on model parameters and flowrates in an attempt to secure the
computational integrity of the model. Specific limits are enumerated in the user
m-file "inputspecifications_dvhemcc01" (available in full licensed
version, not available as part of the 30-day free Demo version).
Although every effort is made to provide an error-free dynamic model the code presented here is not guaranteed to be error free or an absolute representation of any real digester. The user assumes all responsibilities for conclusions and designs reached as a result of exercising this model. IETek will not be liable to the user for any special, consequential, direct or indirect damages, including any lost profits, lost data or lost staff time arising from the use or inability to use the model code.
For additional simulation results see the Advanced Digester Model section.
A SAMPLE OF GUI DURING A
A SAMPLE OF GUI DURING
SPECIE SWING FROM SOFTWOOD TO HARDWOOD
A SAMPLE OF GUI AFTER THE SWING WITH ALTERNATE PLOT SELECTIONS
For additional information or questions please contact
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Tel: (253) 925-2179, Fax: (253) 925-5023
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