Nonlinear Control of Fouling in Polyethylene Reactors

Fakhrony Sholahudin Rohman; Mohd Roslee Othman; Dinie Muhammad; Ashraf Azmi; Iylia Idris; Rushdan Ahmad Ilyas; Samah Elsayed Elkhatif; Muhammad Nazri Murat

doi:10.1021/acsomega.2c03078

Nonlinear Control of Fouling in Polyethylene Reactors

ACS Omega. 2022 Oct 30;7(44):39648-39661. doi: 10.1021/acsomega.2c03078. eCollection 2022 Nov 8.

Authors

Fakhrony Sholahudin Rohman¹, Mohd Roslee Othman¹, Dinie Muhammad¹, Ashraf Azmi², Iylia Idris², Rushdan Ahmad Ilyas^{3

4

5}, Samah Elsayed Elkhatif⁶, Muhammad Nazri Murat¹

Affiliations

¹ School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, Nibong Tebal, 14700Penang, Malaysia.
² School of Chemical Engineering, College of Engineering, Universiti Teknologi MARA, Shah Alam, 40450Selangor, Malaysia.
³ School of Chemical and Energy Engineering, Faculty of Engineering, Universiti Teknologi Malaysia (UTM), Johor Bahru, 81310Johor, Malaysia.
⁴ Centre for Advanced Composite Materials (CACM), Universiti Teknologi Malaysia (UTM), Johor Bahru, 81310Johor, Malaysia.
⁵ Institute of Tropical Forestry and Forest Products, Universiti Putra Malaysia (UPM), Serdang, 43400Selangor, Malaysia.
⁶ Mechanical Engineering, Faculty of Engineering and Technology, Future University in Egypt, New Cairo11845, Egypt.

Abstract

Fouling formation in reactor vessels poses a serious threat to the safe operation of the industrial low-density polyethylene (LDPE) polymerization. Fouling also degrades the polymer quality and causes productivity loss to some extent. In this work, neural Wiener model predictive control (NWMPC) is introduced to address the fouling concern. In addition, a soft sensor model is used to activate the fouling-defouling (F-D) mechanism when the fouling surpasses the thickness limit to prevent vessel overheating. NWMPC is proven to be fast, stable, and robust under various control scenarios. The use of a soft sensor model in conjunction with NWMPC enables the online monitoring and controlling of the F-D processes. When comparison is made with a state space (SSMPC) utilizing only the linear block, NWMPC is found to be able to control the LDPE grade with quicker grade transition and lower resource consumption.