Simulations of sorbent regeneration in a circulating fluidized bed system for sorption enhanced steam reforming with dolomite--颗粒学报PARTICUOLOGY

Phuakpunk, K., Chalermsinsuwan, B., Putivisutisak, S., & Assabumrungrat, S. (2020). Simulations of sorbent regeneration in a circulating fluidized bed system for sorption enhanced steam reforming with dolomite. Particuology, 50, 156-172. https://doi.org/10.1016/j.partic.2019.08.005

Simulations of sorbent regeneration in a circulating fluidized bed system for sorption enhanced steam reforming with dolomite

Kiattikhoon Phuakpunk ^{a b}, Benjapon Chalermsinsuwan ^{c d e *}, Sompong Putivisutisak ^{e f}, Suttichai Assabumrungrat ^{a e}

a Center of Excellence in Catalysis and Catalytic Reaction Engineering, Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, 10330, Thailand
b Energy Research Institute, Chulalongkorn University, Bangkok, 10330, Thailand
c Fuels Research Center, Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand
d Center of Excellence on Petrochemical and Materials Technology, Chulalongkorn University, Bangkok, 10330, Thailand
e Advanced Computational Fluid Dynamics Research Unit, Chulalongkorn University, Bangkok, 10330, Thailand
f Department of Mechanical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, 10330, Thailand

10.1016/j.partic.2019.08.005

Volume 50, June 2020, Pages 156-172

Received 13 July 2018, Revised 20 October 2018, Accepted 28 August 2019, Available online 11 November 2019, Version of Record 7 April 2020.

E-mail: Benjapon.C@chula.ac.th

Highlights

• Dolomite was the selected sorbent for sorption enhanced steam reforming.

• Dolomite decarbonation kinetics was investigated via multiphase fluid dynamic models.

• The sorbent regenerator was preliminary designed in a 2D system.

• Used dolomite could be completely regenerated through double stage regenerators.

Abstract

In this work, the sorption enhanced steam reforming (SESR) method was developed for improved hydrogen (H₂) production, and the drawbacks of conventional steam reforming processes on H₂ yield and purity were overcome. However, the SESR process is discontinuous and requires regeneration after sorbent saturation with CO₂. The circulating fluidized bed reactor (CFBR) system has previously been proposed for continuous H₂ production, with both reforming and sorbent regeneration occurring simultaneously. The main aim of this work was to determine the feasibility and performance of SESR with a proper design and conditions in conjunction with the CFBR system. The reforming riser and bubbling bed regenerator are studied separately but related to each other. Two-dimensional transient models using the Euler‒Euler approach and kinetic theory of granular flow were used for fluid dynamic simulations combined with the decarbonation kinetics of dolomite, to investigate a conceptual regenerator system and determine its key conditions. A mixture of the Ni-based catalyst and dolomite from the risers was injected with a flux of 200 kg/(m² s) and a catalyst to sorbent ratio of 2.54 kg/kg. A double-stage bubbling bed regenerator system was designed with 1.2 m width, 0.8 m bed height, a gas inlet velocity of 0.2 m/s and solid preheating at 950 °C. The used dolomite was regenerated with an assumed CaO conversion of 3%; the almost fresh dolomite was then released with good mixing of the catalyst and sorbent.

Graphical abstract

Keywords

CaO sorbent; Regenerator; Computational fluid dynamics; Circulating fluidized bed; Multiphase flow model

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