Detailed gas/particle flow characteristics of an improved down-fired boiler with respect to a critical factor affecting coal burnout: Vent-air inclination angle

Qingxiang Wang, Zhichao Chen, Hui Han, Yaojie Tu, Guangkui Liu, Lingyan Zeng and Zhengqi Li

Energy, 2019, vol. 182, issue C, 570-584

Abstract: The eccentric-swirl-secondary-air combustion technology has been confirmed to comprehensively solve high NOx emission and poor coal burnout for down-fired boilers with swirl burners. The influence of vent-air inclination angle (βv), a critical factor that affects coal burnout, on gas/particle flow characteristics is investigated to further decrease unburned combustible in fly ash. Gas/particle two-phase flow experiments under different βv (i.e., 10°, 20°, 28°, 40° and 50°) are performed by using a particle dynamic analyser in a 1:10-scale model of the full-scale improved boiler. With increasing βv, the under-arch recirculation zone and the recirculation velocities of gas/particle flows continuously increase. In the staged air region, the vertical velocities of gas/particle flows near water-cooled wall for βv of 40° and 50° are still as high as 2–4 m/s, however, the vertical velocities of gas/particle flows basically decay to negative values for smaller βv of 10° and 20°. At furnace section Y/Y0 from 0.220 to 0.369, the vertical fluctuation velocities of gas/particle flows near water-cooled wall for βv of 40° and 50° are significantly higher than those with βv of 10°, 20° and 28°, and the particle volume flux at the same horizontal position X/X0 constantly increases with increasing βv. Furthermore, the downward ejection ability of vent air to gas/particle flows from burners continuously improves, and the downward depth of gas/particle flows and the space utilization ratio of lower furnace both increase with increasing βv. The appropriate inclination angle of vent air for the improved boiler varies from 40° to 50°.

Keywords: Down-fired boiler; Novel combustion technology; Vent-air inclination angle; PDA; Gas/particle flow characteristics; Pulverized coal burnout (search for similar items in EconPapers)
Date: 2019
References: Add references at CitEc
Citations: View citations in EconPapers (4)

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0360544219311867
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:182:y:2019:i:c:p:570-584

DOI: 10.1016/j.energy.2019.06.057

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 ().