Neural - Wiener Model for Multivariable Methyl Tertiary Butyl Ether (MTBE) Reactive Distillation

2013 ◽  
Vol 284-287 ◽  
pp. 409-413
Author(s):  
Sudibyo Sudibyo ◽  
Muhamad Nazri Murat ◽  
Norashid Aziz
Keyword(s):  
Reactive Distillation ◽  
State Space Model ◽  
Nonlinear Behavior ◽  
Distillation Process ◽  
Wiener Model ◽  
Butyl Ether ◽  
Separation Processes ◽  
Tertiary Butyl ◽  
Highly Nonlinear ◽  
Reliable Model

MTBE is a chemical that can be used as anti-knock additive to replace lead additive (tetra ethyl lead) which can be efficiently produced using reactive distillation process. It has been established in the literature that MTBE reactive distillation poses a highly nonlinear behavior due to the combination of reaction and separation processes. A reliable model for predicting the behavior is required especially for the control purposes. In this work, a Neural Wiener model which is one of the available types of oriented block model was utilised to develop the MTBE reactive distillation model. The required data for the Neural Wiener model were generated using a validated Aspen dynamics model for the MTBE reactive distillation process. It is found that the Neural Wiener model is capable to predict the MTBE purity and isobutene conversion with accuracy of 98.55% and 96.95%, respectively. Those values are quantitatively better in comparison to the state space model which gives lower values for prediction accuracy of 87.86% and 82.90%, respectively.

Simulation of Methyl Tertiary Butyl Ether Production in Catalytic Distillation

2012 ◽  
Vol 263-266 ◽  
pp. 444-447
Author(s):  
Jin Nan Chen ◽  
Yu Chun Zhang ◽  
Xing Yong Sun
Keyword(s):  
Relative Error ◽  
Conversion Rate ◽  
Model Development ◽  
Methyl Tertiary Butyl Ether ◽  
Reflux Ratio ◽  
Distillation Process ◽  
Butyl Ether ◽  
Catalytic Distillation ◽  
Design Data ◽  
Tertiary Butyl

The software of the catalytic distillation process of methyl tertiary butyl ether was developed by using Process Simulation System Platform. The isobutylene conversion rate was calculated by using the catalytic distillation software. The relative error of isobutylene conversion rate between the simulation results and the design data from the China Petroleum Hohhot Petrochemical Co. was less than 5%. The relative error satisfies industrial design requirements. At present, enterprise workers use this software to learn how to operate the catalytic distillation process. The catalytic distillation software is further used to study the influence of reaction temperature and reflux ratio on the isobutylene conversion rate which can be used for future empirical model development and control studies.

Neural Wiener Based Model Predictive Control (NWMPC) for MTBE Catalytic Distillation Using Reduced Sequential Quadratic Programming (RSQP)

2015 ◽  
Vol 1113 ◽  
pp. 733-738
Author(s):  
Sudibyo Sudibyo ◽  
Muhamad Nazri Murat ◽  
Norashid Aziz
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
Reactive Distillation ◽  
Nonlinear Behavior ◽  
Strong Interactions ◽  
Catalytic Distillation ◽  
Unit Process ◽  
Reaction Conversion ◽  
Highly Nonlinear ◽  
Control Study

Reactive distillation is a process that combines both reactor and distillation column in one unit process. The reactive distillation is normally applied in MTBE production in order to achieve high reaction conversion and purity of the MTBE. Controlling such reactive distillation is a challenging task due to its highly nonlinear behavior and the existence of strong interactions among control variables. In this work, a Neural Wiener based model predictive control (NWMPC) is designed and implemented to control the tray temperature of MTBE reactive distillation. The Reduced SQP (RSQP) has been embedded as an optimizer in the NWMPC proposed. The MTBE reactive distillation has been modeled using aspen dynamic and the control study has been simulated using Simulink (Matlab) which is integrated with Aspen dynamic model. The results achieved show that the NWMPC is able to maintain tray temperatures at desired set points, able to reject the disturbance and robust toward robustness test conducted.

scholarly journals Modeling Of A Reactive Distillation Column: Methyl Tertiary Butyl Ether (Mtbe) Simulation Studies

1970 ◽  
Vol 4 (2) ◽  
Author(s):  
Ismail Mohd Saaid Abdul Rahman Mohamed and Subhash Bhatia
Keyword(s):  
Distillation Column ◽  
Reactive Distillation ◽  
Relaxation Method ◽  
Differential Algebraic Equations ◽  
Operating Conditions ◽  
Integration Scheme ◽  
Algebraic Equations ◽  
Butyl Ether ◽  
Tertiary Butyl ◽  
Proposed Model

A process simulation stage-wise reactive distillation column model formulated from equilibrium stage theory was developed. The algorithm for solving mathematical model represented by sets of differential-algebraic equations was based on relaxation method. Numerical integration scheme based on backward differentiation formula was selected for solving the stiffness of differential-algebraic equations. Simulations were performed on a personal computer (PC Pentium processor) through a developed computer program using FORTRAN90 programming language. The proposed model was validated by comparing the simulated results with the published simulation results and with the pilot plant data from the literature. The model was capable of predicting high isobutene conversion for heterogeneous system, as desirable in industrial MTBE production process. The comparisons on temperature profiles, liquid composition profile and operating conditions of reactive distillation column also showed promising results. Therefore the proposed model can be used as a tool for the development and simulation of reactive distillation column.Keywords: Modeling, simulation, reactive distillation, relaxation method, equilibrium stage, heterogeneous, MTBE

Process Parameters Optimization of the MTBE Reactive Distillation by Orthogonal Numberical Test and Least Square Method

2012 ◽  
Vol 550-553 ◽  
pp. 947-952
Author(s):  
Wu Xiao ◽  
Yan Yan Zhou ◽  
Shou Cheng Du ◽  
Gao Hong He
Keyword(s):  
Process Parameters ◽  
Reactive Distillation ◽  
Numerical Test ◽  
Least Square Method ◽  
Parameters Optimization ◽  
Least Square ◽  
Butyl Ether ◽  
Process Parameters Optimization ◽  
Tertiary Butyl ◽  
The Relationship

Because of the large number of operating and equipment parameters of the reactive distillation(RD) and a strong coupling between them, it is difficult to find the optimal process parameters. A novel hybrid method on process parameters optimization of methyl tertiary butyl ether (MTBE) RD was developed in the paper. MTBE RD process was firstly simulated with Aspen Plus. Then based on the MTBE RD model, sensitivity analysis of various parameters was accomplished to determine the key decision parameters. After that, the orthogonal numerical tests were performed in feasible fields to obtain nearly optimal parameters. Finally, with the orthogonal numerical test results, the least square method was used to regress equation, which showed the relationship between objective function and the key decision parameters, thus determining the optimal operating parameters and equipment parameters. Results of analysis indicated that the combination of orthogonal numerical test and the least square method can be attractive since the number of tests was reduced substantially while the specification of the products can be met.

scholarly journals Operability Analysis of MTBE Reactive Distillation Column using a Process Simulator

2009 ◽  
Vol 4 (3) ◽  
Author(s):  
Herry Santoso ◽  
Jie Bao ◽  
Peter L Lee
Keyword(s):  
Steady State ◽  
Process Design ◽  
Distillation Column ◽  
Reactive Distillation ◽  
Design Parameters ◽  
Hammerstein Model ◽  
Reflux Ratio ◽  
Tertiary Butyl ◽  
Highly Nonlinear ◽  
Process Simulator

It has been understood for decades that process operability does not depend entirely upon the control system but also on the inherent properties of the process itself. For example, the decision on the size of equipment or the use of a highly integrated process may have a significant impact on the overall operability. Ignoring operability during process design may lead to a very difficult to control process. In this paper, a dynamic operability analysis of a Methyl Tertiary Butyl Ether (MTBE) reactive distillation column is presented. The effects of two design parameters, i.e. the reboiler duty and the reflux ratio, on the operability of the reactive distillation system are studied. Process operability is defined as the ability of the process to return to the steady-state in spite of unknown but bounded disturbances. The nonlinearity of the process is represented using a Hammerstein model, which can be easily obtained during process design from the steady-state model combined with some limited information on the process dynamics. The recent operability analysis method proposed by Rojas et al. (2007) is extended such that it can be implemented conveniently as one extra step after the flowsheet simulation using a process simulator. Based on this approach, an optimal controller for this highly nonlinear process is determined by solving a linear matrix inequality (LMI) optimization problem.

Influence of the reactive distillation column configuration on its performance: A computational study

2008 ◽  
Vol 62 (1) ◽  
Author(s):  
Zuzana Švandová ◽  
Jozef Markoš ◽  
L’udovít Jelemenský
Keyword(s):  
Flow Rate ◽  
Distillation Column ◽  
Reactive Distillation ◽  
Computational Study ◽  
Reaction System ◽  
Reflux Ratio ◽  
Feed Flow Rate ◽  
Butyl Ether ◽  
Dynamic Simulations ◽  
Tertiary Butyl

AbstractComparison of the performance of a reactive distillation column with three different hardware configurations is presented. As a reaction system the methyl tertiary-butyl ether (MTBE) synthesis has been chosen. The sieve tray columns with catalyst (encased inside wire gauze envelopes) placed along the liquid flow path differ in the number of reactive trays. The column simulations have been performed using the nonequilibrium model. The steady state behaviour of the three different hardware configurations was studied regarding the three input parameters; feed flow rate of methanol, feed flow rate of butenes, and reflux ratio. It has been shown that by varying the location of the methanol feed stage, the columns exhibit significantly different solution diagrams using the butenes feed flow rate as a continuation parameter. Using dynamic simulations, different perturbations of the manipulated variables were found to cause transitions between multiple steady states and these were also investigated. The major objective of this paper is to demonstrate the importance of the hardware choice in the performance of a reactive distillation column e.g. during the start-up or if occasional variations of the operating parameters occur.

scholarly journals Multi-Output Soft Sensor with a Multivariate Filter That Predicts Errors Applied to an Industrial Reactive Distillation Process

Mathematics ◽  
2021 ◽  
Vol 9 (16) ◽  
pp. 1947
Author(s):  
Vladimir Klimchenko ◽  
Andrei Torgashov ◽  
Yuri A. W. Shardt ◽  
Fan Yang
Keyword(s):  
Distillation Column ◽  
Reactive Distillation ◽  
Optimal Estimation ◽  
Soft Sensor ◽  
Methyl Tert Butyl Ether ◽  
Model Errors ◽  
Distillation Process ◽  
Butyl Ether ◽  
Predict Model ◽  
Estimation Of Time

The paper deals with the problem of developing a multi-output soft sensor for the industrial reactive distillation process of methyl tert-butyl ether production. Unlike the existing soft sensor approaches, this paper proposes using a soft sensor with filters to predict model errors, which are then taken into account as corrections in the final predictions of outputs. The decomposition of the problem of optimal estimation of time delays is proposed for each input of the soft sensor. Using the proposed approach to predict the concentrations of methyl sec-butyl ether, methanol, and the sum of dimers and trimers of isobutylene in the output product in a reactive distillation column was shown to improve the results by 32%, 67%, and 9.5%, respectively.

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