18
Views
7
CrossRef citations to date
0
Altmetric
Original Articles

Near-Limit Combustion in Spouted and in Crater Beds

, &
Pages 1-24 | Received 12 Dec 1990, Accepted 25 Mar 1991, Published online: 06 Apr 2007
 

Abstract

Combustion in spouted and in crater beds is studied under very fuel-lean and very fuel-rich conditions and compared with burning in an electrically heated fixed bed. Ultra-lean mixtures are relevant to burning low calorific value reactants, whilst burning beyond the rich limit allows self-sustaining partial oxidation reactions to proceed economically. The common aim is to employ heat recirculation by the bed in order to pre-vaporise or pre-gasify (in the case of solid or liquid fuels), pre-heat and pre-mix prior to combustion. The conclusions of this very extensive study include a model which successfully predicts flame stability limits, as well as a critical comparison of crater- with spouted-beds. The former, unlike the latter, can operate with the smallest of particles (dusts) and are not subject to minimum spouting depth limitations; however the fountain in the crater is not effective in recirculating heat. Nonetheless, by extending the heat transfer surface of the inlet tube, much leaner mixtures can be burned in crater beds. Means of increasing the residence time of coal particles in spouted beds in order to improve burn-out of the ungasified fractions, even in small laboratory systems, are presented.

Additional information

Notes on contributors

MARCUS GOVER

AEA Environment & Energy, Harwell, OX 11 0RA, UK.

NUSRAT KERMANI

The University. Leeds. LS2 9JT. UK.

Reprints and Corporate Permissions

Please note: Selecting permissions does not provide access to the full text of the article, please see our help page How do I view content?

To request a reprint or corporate permissions for this article, please click on the relevant link below:

Academic Permissions

Please note: Selecting permissions does not provide access to the full text of the article, please see our help page How do I view content?

Obtain permissions instantly via Rightslink by clicking on the button below:

If you are unable to obtain permissions via Rightslink, please complete and submit this Permissions form. For more information, please visit our Permissions help page.