Abstract

The effects of reaction parameters, including reaction temperature and space velocity, on hydrogen production via steam reforming of methane (SRM) were investigated using lab- and bench-scale reactors to identify critical factors for the design of large-scale processes. Based on thermodynamic and kinetic data obtained using the lab-scale reactor, a series of SRM reactions were performed using a pelletized catalyst in the bench-scale reactor with a hydrogen production capacity of 10 L/min. Various temperature profiles were tested for the bench-scale reactor, which was surrounded by three successive cylindrical furnaces to simulate the actual SRM conditions. The temperature at the reactor bottom was crucial for determining the methane conversion and hydrogen production rates when a sufficiently high reaction temperature was maintained (>800 °C) to reach thermodynamic equilibrium at the gas-hourly space velocity of 2.0 L CH4/(h·gcat). However, if the temperature of one or more of the furnaces decreased below 700 °C, the reaction was not equilibrated at the given space velocity. The effectiveness factor (0.143) of the pelletized catalyst was calculated based on the deviation of methane conversion between the lab- and bench-scale reactions at various space velocities. Finally, an idling procedure was proposed so that catalytic activity was not affected by discontinuous operation.

Highlights

  • The demand for hydrogen has traditionally been high because hydrogen has been widely used as a chemical raw material in various refineries, as it is essential for the Fischer–Tropsch process and methanol synthesis [1,2]

  • Preliminary lab-scale reactions were performed using a powder-type catalyst obtained by grinding a commercial pellet-type catalyst and sieving it through a 16–20 size mesh

  • It should be noted that the temperature at the catalyst bed reported here was somewhat underestimated compared to the overall reactor system, so the experimental values could exceed the equilibrium values calculated based on the temperature of the catalyst bed

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Summary

Introduction

The demand for hydrogen has traditionally been high because hydrogen has been widely used as a chemical raw material in various refineries, as it is essential for the Fischer–Tropsch process and methanol synthesis [1,2]. Hydrogen is expected to play an important role as a carbon-free energy carrier in the future [3,4]. Various methods for producing hydrogen with renewable energies have been proposed over the past few decades [5,6,7,8,9,10,11,12,13]. Large-scale commercialization of hydrogen production using renewable energy to meet the massive demand for hydrogen remains challenging [14,15,16]. Until hydrogen production technology using renewable energy is sufficiently mature to facilitate the implementation of a sustainable hydrogen economy, a large amount of hydrogen is required to construct and operate the infrastructure for its storage, transportation, and utilization.

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