Combustion characteristics of low-quality lignite for different bed material sphericities in a circulating fluidized bed boiler: A numerical study--颗粒学报PARTICUOLOGY

Gürel, B., Karaca Dolgun, G., İpek, O., & Keçebaş, A. (2024). Combustion characteristics of low-quality lignite for different bed material sphericities in a circulating fluidized bed boiler: A numerical study. Particuology, 90, 364-382. https://doi.org/10.1016/j.partic.2023.12.011

Combustion characteristics of low-quality lignite for different bed material sphericities in a circulating fluidized bed boiler: A numerical study

Barış Gürel^a, Gülşah Karaca Dolgun ^b *, Osman İpek ^a, Ali Keçebaş ^b

a Department of Mechanical Engineering, Engineering Faculty, Süleyman Demirel University, Çünür, Isparta, Turkey
b Department of Energy Systems Engineering, Technology Faculty, Muğla Sıtkı Koçman University, Kötekli, Menteşe, Muğla, Turkey

10.1016/j.partic.2023.12.011

Volume 90, July 2024, Pages 364-382

Received 8 May 2023, Revised 7 November 2023, Accepted 18 December 2023, Available online 28 December 2023, Version of Record 8 February 2024.

E-mail: gulsahkaraca1@gmail.com

Highlights

• Investigates the influence of bed material sphericity on combustion processes.

• Examines mole fractions of CO₂, CO, H₂O, and O₂ within the circulating fluidized bed boiler (CFBB).

• Analyzes temperature, pressure, NO_x, and SO₂ distributions in the CFBB.

• Explores the potential for reducing energy consumption in the boiler.

• Emphasizes the enhanced combustion efficiency associated with lower sphericity.

Abstract

This study delves into the combustion behavior of various lignite types within a circulating fluidized bed boiler (CFBB), with a primary focus on the impact of different bed material sphericity ratios (0.5, 0.7, and 0.9). Utilizing bed material with a sphericity ratio of 0.9 sourced from the Çan power plant and verified through experimentation, the research reveals several key findings. Notably, furnace temperatures tended to rise with higher sphericity ratios, albeit with variations between lignite types, particularly highlighting the complexity of this relationship in the case of GLI-Tunçbilek lignite. Pressure levels in the combustion chamber remained consistent across different sphericity ratios, indicating minimal influence on pressure dynamics. Improved combustion efficiency, especially at the bottom of the boiler, was observed at lower sphericity levels (0.5 and 0.7) for Çan lignite, as reflected in CO₂ mole fractions. While NO_x emissions generally decreased with lower sphericity, the sensitivity to sphericity varied by lignite type, with Ilgın lignite showcasing low NO_x but high SO₂ emissions, underscoring the intricate interplay between lignite properties, sphericity, and emissions. Overall, this study advances our understanding of CFBB combustion dynamics, offering insights valuable for optimizing performance and emissions control, particularly in lignite-based power.

Graphical abstract

Keywords

Circulating fluidized bed boiler; Computational particle fluid dynamics method; Particle sphericity ratios; NO_x and SO₂ emissions; Energy production efficiency

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