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Optimization studies of low-density polyethylene process: effect of different interval numbers

  • Ashraf Azmi , Suhairi Abdul Sata ORCID logo , Fakhrony Sholahudin Rohman and Norashid Aziz EMAIL logo
Published/Copyright: June 1, 2020
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Chemical Product and Process Modeling
From the journal Chemical Product and Process Modeling Volume 15 Issue 4

Abstract

The highly exothermic nature of the low-density polyethylene (LDPE) polymerization process and the heating-cooling prerequisite in tubular reactor can lead to various problems particularly safety and economic. These issues complicate the monomer conversion maximization approaches. Consequently, the dynamic optimization study to obtain maximum conversion of the LDPE is carried out. A mathematical model has been developed and validated using industrial data. In the dynamic optimization study, maximum monomer conversion (XM) is considered as the objective function, whereas the constraint and bound consists of maximum reaction temperature and product melt flow index (MFI). The orthogonal collocation (OC) on finite elements is used to convert the original optimization problems into Nonlinear Programming (NLP) problems, which are then solved using sequential quadratic program (SQP) methods. The result shows that five interval numbers produce better optimization result compared to one and two intervals.

Keywords: dynamic optimization; low-density polyethylene; nonlinear programming; tubular reactor
Corresponding author: Norashid Aziz, School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, Seri Ampangan, Nibong, Tebal, Seberang Perai Selatan, 14300, Pulau Pinang, Malaysia, E-mail:

Funding source: Ministry of Higher Education, Malaysia

Award Identifier / Grant number: 203/PJKIMIA/6071368

Acknowledgment

The financial support from Kementerian Pengajian Tinggi (KPT) through Grant No. 203/PJKIMIA/6071368 and MyBrain15's Fund to the first author are greatly acknowledged.

List of symbols
Bb

Backbiting

Fx

Mass flow rate of x component (kg/h)

I

Initiator

M

Monomer

px

Input variable of x component

P(x)

Live radical with chain length x

R(x)

Live radical with chain length x

S

Solvent

T

Temperature (°C)

Tin

Reactor inlet temperature (°C)

TJ

Reactor jacket temperature (°C)

Tmax

Maximum reaction temperature (°C)

U

Overall heat transfer coefficient (cal/cm2.s.K)

  1. Author contribution: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.

  2. Research funding: None declared.

  3. Employment or leadership: None declared.

  4. Honorarium: None declared.

  5. Conflict of interest statement: The authors declare no conflicts of interest regarding this article.

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Received: 2019-11-19
Accepted: 2020-04-01
Published Online: 2020-06-01

© 2020 Walter de Gruyter GmbH, Berlin/Boston

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https://doi.org/10.1515/cppm-2019-0125
Keywords for this article
dynamic optimization; low-density polyethylene; nonlinear programming; tubular reactor

Articles in the same Issue

  1. Research Articles
  2. Simulation of an Acid Gas Removal Unit Using a DGA and MDEA Blend Instead of a Single Amine
  3. An Investigation on the Performance of an Oxidation Catalyst Using Two-dimensional Simulation with Detailed Reaction Mechanism
  4. Bioprocess Optimization of L-Lysine Production by Using RSM and Artificial Neural Networks from Corynebacterium glutamicum ATCC13032
  5. Short Communication
  6. Exergoenvironmental Analysis of Tetrahydrofuran/Ethanol Separation through Extractive and Pressure-Swing Distillation
  7. Special section dedicated to selected extended papers from the 26th Regional Symposium on Chemical Engineering (RSCE 2019) held on Oct. 29 to Nov. 1, 2019 in Kuala Lumpur, Malaysia
  8. Editorial
  9. Editorial special section: selected extended papers from the 26th Regional Symposium on Chemical Engineering (RSCE 2019)
  10. Research Articles
  11. Mixed-integer non-linear programming (MINLP) multi-period multi-objective optimization of advanced power plant through gasification of municipal solid waste (MSW)
  12. A mixed integer nonlinear programming approach for integrated bio-refinery and petroleum refinery topology optimization
  13. Development and validation of mathematical model of hydrotropic-reactive extraction of lignin
  14. Optimization studies of low-density polyethylene process: effect of different interval numbers
  15. Modeling and simulation of the hollow fiber bore size on the CO2 absorption in membrane contactor
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