Optimization and Control of Propylene Production by Metathesis of 2-Butene

Abstract

This article considers the design and control of the 2-butene metathesis process. The process transforms a low-value feedstock derived from a fluid catalytic cracking unit into more valuable products. The economical optimization is applied to the preheat–reaction and separation sections, with the objective of minimizing the total annual cost. The dynamic response and control of the plant are evaluated for feed flow perturbations. Although the process control system acts as a first line of defense against potential hazards, other independent safety layers are discussed with safety limits specific to the critical equipment of the 2-butene metathesis unit. The results prove that the metathesis reaction of 2-butene over a mesoporous tungsten catalyst is economically attractive. For a 5.7 t/h feed rate consisting of 2-butene (70% molar) and n-butane (30% molar), a reaction–separation plant (without recycle) requires 6570 × 103 $ investment and has a profitability of 2300 × 103 $/year.

Linear Model Predictive Control of Olefin Metathesis Process

“…This work proves that linear model predictive control of the 2-butene metathesis process [25] has a much better performance compared to the conventional process control. The methodology is similar to the industrial approach.…”

“…The design of the 2-butene metathesis process is described in an earlier paper [25], where Aspen Plus version 10 was used for steady-state simulation and evaluation. After equipment sizing, a flow-driven Aspen Plus Dynamics simulation model is obtained.…”

“…Figure 1 presents the flowsheet of the 2-butene metathesis process [25]. The fresh feed is a mixture of 2-butene (reactant) and n-butane (inert) in a 70:30 mol% ratio.…”

“…This process is of industrial interest [24]. In a previous work [25], the design, optimization, and basic process control of the 2-butene metathesis process were investigated. The present work completes the endeavor by studying the applicability of MPC to the metathesis process.…”