Efficient and low-NOx combustion in a grate-fired boiler by feeding biomass non-uniformly along grate width: An integrated modeling study with experimental validation

Xianqiang Su, Qingyan Fang, Lun Ma, Cheng Zhang, Gang Chen, Chungen Yin and Wenming Yang

Energy, 2024, vol. 312, issue C

Abstract: The distribution of air flows and fuel feeds are two crucial operational parameters determining the high-efficiency combustion and low-nitrogen emissions in biomass-fired grate boilers. However, current optimizations primarily focus on air distribution, with limited attention given to fuel feeds optimization. In this study, a three-dimensional integrated model was developed in FLUENT platform for simulating a grate-fired boiler with four feed inlets, in which the DPM model was adopted to track particle information in detail, and the Ergun model was used to account for the flow resistance generated by the thick packed bed, implemented in the form of a UDF code. The reliability of the model was validated through comprehensive on-site experimental data. It was found that key parameters such as temperature and ignition front of char are non-uniformly distributed along the width of the four grates. Specifically, a significant lag in volatiles release and char oxidation occurs near the water-cooled wall on both sides. On this basis, the optimization strategies on improving efficient and low-NOx combustion were proposed by redistributing the biomass fuel from near the sidewalls to the middle sections, and the optimal non-uniform feeding mode along the grate width was found. Results demonstrate that when the mass ratio of fuel between the middle and side grates is 0.30 to 0.20, yielding a maximum overall char burnout ratio of 84.74 %. Additionally, the concentration of NO decreases from 163.2 mg/m3 of uniform feeding mode to 149.4 mg/m3 (at 11 % O2). These predictions will provide reliable theoretical guidance for enhancing boiler efficiency and reducing NOx emissions in grate-fired boilers.

Keywords: Grate boiler; Non-uniform feeding; DPM model; Integrated model; Efficient and low-NOx combustion (search for similar items in EconPapers)
Date: 2024
References: View references in EconPapers View complete reference list from CitEc
Citations:

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0360544224033619
Full text for ScienceDirect subscribers only

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:energy:v:312:y:2024:i:c:s0360544224033619

DOI: 10.1016/j.energy.2024.133583

Access Statistics for this article

Energy is currently edited by Henrik Lund and Mark J. Kaiser

More articles in Energy from Elsevier
Bibliographic data for series maintained by Catherine Liu ().