Control of catalytic flow reversal reactors

• Main Author: Aw, You Wei
• Other Authors: Vinay Kumar Kariwala
• Format: Final Year Project
• Language: English
• Published: 2009
• Subjects: DRNTU::Engineering::Chemical engineering::Processes and operations
• Online Access: http://hdl.handle.net/10356/16677
• Institution: Nanyang Technological University

Catalytic flow reversal reactor (CFRR) is a special type of reactor that traps heat generated by exothermic reactions and utilizes the heat to preheat the feed. To do so, it reverses the feed flow direction periodically. However, without an effective control system in place to control the amount of heat in the reactor, the CFRR can either extinguish or overheat if feed conditions are extreme and prolonged. Thus, an effective control system must be implemented. It is widely perceived that Proportional-Integral-Derivative (PID) controllers are superior in performance as compared to simple on-off controllers. In this thesis, the performance of the PI controller for control of CFRR is investigated and is compared with the on-off controller using a simulation model constructed using COMSOL Multiphysics®. Both on-off and PI controllers are implemented for heat and mass extraction strategies. The controllers are designed to control the amount of heat or mass extracted at the midsection of the reactor, with the objective of operating the reactor at the highest possible temperature for optimal conversion of methane, and at the same time without violating the upper temperature constraint in the catalyst beds. The results suggested that the average outlet methane concentration is slightly lower and efficiency slightly higher using both P and PI control as compared to on-off control.