Mohammad Shahrokhi
Department of Chemical and Petroleum Engineering, Sharif University of Technology, P.O. Box 11365-9465 Tehran, I.R. IRAN
[ 1 ] - Chaos Control in a Non-Isothermal Autocatalytic Chemical Reactor
In this paper, a reaction system consisting of two parallel, non-isothermal autocatalytic reactions in a Continuous Stirred Tank Reactor (CSTR) has been considered. Reactor chaotic behavior is possible for certain values of system parameters. Two types of controllers are designed and compared in order to control both the reactor temperature and the product concentration. T...
[ 2 ] - Simulation, Optimization & Control of Styrene Bulk Polymerization in a Tubular Reactor
In this paper, optimization and control of a tubular reactor for thermal bulk post-polymerization of styrene have been investigated. By using the reactor mathematical model, static and dynamic simulations are carried out. Based on an objective function including polymer conversion and polydispersity, reactor optimal temperature profile has been obtained. In the absence of model mismatch, de...
[ 3 ] - Control of a Chemical Reactor with Chaotic Dynamics
In this paper, control of a non-isothermal continuous stirred tank reactor in which two parallel autocatalytic reactions take place has been addressed. The reactor shows chaotic behavior for a certain set of reactor parameters. In order to control the product concentration, an optimal state feedback controller has been designed. Since concentrations of reactor species are ...
[ 4 ] - Fault Diagnosis in a Yeast Fermentation Bioreactor by Genetic Fuzzy System
In this paper, the fuzzy system has been used for fault detection and diagnosis of a yeast fermentation bioreactor based on measurements corrupted by noise. In one case, parameters of membership functions are selected in a conventional manner. In another case, using certainty factors between normal and faulty conditions the optimal values of these parameters have been obtained through the g...
[ 5 ] - Adaptive Input-Output Linearization Control of pH Processes
pH control is a challenging problem due to its highly nonlinear nature. In this paper the performances of two different adaptive global linearizing controllers (GLC) are compared. Least squares technique has been used for identifying the titration curve. The first controller is a standard GLC based on material balances of each species. For implementation of this controller a nonlinear state...
[ 6 ] - Control of a Fluidized Bed Polyethylene Reactor
In present paper, dynamic behavior and control of a fluidized bed reactor for polyethylene production has been considered. A double active sites model for Ziegler-Natta catalysts is used for simulation of polymerization reaction. Hydrodynamic behavior of the bed is modeled using a two phase model including bubble and emulsion phases in which bubble phase has plug flow pattern with different...
[ 7 ] - Simulation and Control of an Aromatic Distillation Column
In general, the objective of distillation control is to maintain the desired products quality. In this paper, the performances of different one point control strategies for an aromatic distillation column have been compared through dynamic simulation. These methods are: a) Composition control using measured composition directly. This method sufferes from large sampling delay of measuring de...
[ 8 ] - Detection of Single and Dual Incipient Process Faults Using an Improved Artificial Neural Network
Changes in the physicochemical conditions of process unit, even under control, may lead to what are generically referred to as faults. The cognition of causes is very important, because the system can be diagnosed and fault tolerated. In this article, we discuss and propose an artificial neural network that can detect the incipient and gradual faults either individually or mutually. The mai...
[ 9 ] - Experimental Evaluation of Batch and Continuous Production of Baker’s Yeast under Computer Controlled pH
Steady state and dynamic fermentations of baker's yeast in molasses based media were analyzed in a laboratory scale bioreactor. Sugar and biomass balances together with the Monod biokinetics were used to develop the process model. Parameters of the model were obtained using collected experimental data. Model predicted open loop responses to step changes in feed concentration as well as dilu...
[ 10 ] - Simulation and Optimization of a Naphtha Thermal Cracking Pilot Plant
In thermal cracking plants, it is desired to apply an optimal temperature profile along the reactor to minimize the operation cost. In this article a simulator is developed by the use of a mathematical model, which describes the static operation of a naphtha thermal cracking pilot plant. The model is used to predict the steady state profiles of the gas temperature and product yields. Using ...
[ 11 ] - A Control System for A Pilot Batch Polymerization Reactor
In this article several control schemes for a pilot scale polymerization reactor are proposed and one of them is selected as the most suitable design. The performances of proposed schemes have been compared through computer simulations. The controllers are PID and Chosen reaction is polymerization of methyl methacrylate which is highly exothermic.
[ 12 ] - Model Predictive Inferential Control of a Distillation Column
Typical production objectives in distillation process require the delivery of products whose compositions meet certain specifications. The distillation control system, therefore, must hold product compositions as near the set points as possible in faces of upset. In this project, inferential model predictive control, that utilizes an artificial neural network estimator and model predictive cont...
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