Advanced Operation of the Steam Methane Reformer by Using Gain-Scheduled Model Predictive Control

Abstract

A rigorous computationally effcient closed-loop system with a gain-scheduled model predictive controller (MPC) is developed for the first time, where a first-principle model of the steam methane reformer is utilized to represent the process dynamics. A dynamic model for a generic primary gas reformer is developed using a homogeneous-phase one-dimensional reaction kinetics model to describe the chemical reactions inside the reforming tubes and to compute the external heat transfer to the reformer tubes by radiation and convection. The gain-scheduled MPC considers critical process parameters of the steam methane reformer such as outlet methane molar concentration and outlet temperature of the reformed gas as the most appropriate and reliable process variables. The developed gain-scheduled MPC demonstrates adaptive and advanced operation of the steam methane reformer at three different steam-to-carbon ratios. By simulation of the set-point changes under the influence of the steam methane reformer critical disturbance rejection performances, it is shown that reformer tubes could operate in a safe temperature range. The model determines optimal trajectories of the reformed syngas outlet temperature and methane outlet molar concentration based on tracking the set point under the influence of the manipulated variablestemperature and mass rate of mixed feed and fuel flow rate for burners. The gain-scheduled MPC is compared with already proven standard process control solutions based on proportional-integral-derivative (PID) controllers. Proposed control strategy benefits include energy savings in the range from 3% to 5% and prolonged lifetime of the reformer tubes and catalyst.

Integrated Method of Monitoring and Optimization of Steam Methane Reformer Process

“…Calculated data confirm the profile shapes regarding recently published work from Zecevic and Bolf [27]. The effectiveness factor of 0.001 was used as the typical value for industrial SMR catalyst installed in the reformer tubes [25].…”

“…where F i represents the molar flux of species i, r i denotes the rate of formation or disappearance of species i given by Xu and Froment [9,10], and l is the distance along the reactor tube. The model is also able to calculate pressure drop and energy balance with related pressure and temperature profile along the reformer tube [9,10,[23][24][25][26][27]. The Newton-Raphson iterative method of solving ordinary differential equations was used.…”

“…Comparison between model and literature data for methane conversion at different steam-to-carbon ratios and temperature range from 400 to 1000 • C at 20 bar[8,11,27].…”

Catalytic Methane Combustion on the Hydrothermally Synthesized MnO2 Nanowire Catalysts

“…The major energy sources in the world are oil, coal, and natural gas. However, fossil fuel consumption increases with the increase in population and industrialization growth. , As a fossil fuel, methane is the major component in natural gas. It is used in various industrial plants such as power stations and petrochemical industries.…”

Experimental Insights into the Coupling of Methane Combustion and Steam Reforming in a Catalytic Plate Reactor in Transient Mode

“…The design of CPR requires the balance between heat input and heat consumption . Significant research efforts have been devoted to achieving better temperature control of the reformer and proper handling of heat to enhance energy efficiency. − In a burner-fired industrial reformer, the heat is supplied mostly via radiative and convective transfer from combustion flames at >1400 °C to the walls of catalyst tubes and via conductive transfer from walls to the catalyst pellets in the tubes. The homogeneous combustion in the industrial burner releases a significant amount of harmful pollutants such as carbon monoxide, nitrogen oxides, and hydrocarbons.…”