Performance Of An Alumina Ball Packed Bed Porous Media Burner Fueled By Producer Gas
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Date
2012-04
Authors
Ho, John Chung eng
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Producer gas from biomass gasification is unable to burn efficiently in
conventional burner due to low burning velocity of CO which comprises of about
20% of the producer gas. Porous media burner (PMB) is a promising technology for
improving combustor performance that could solve the problem. The study aims to
investigate the performance of PMB fueled by producer gas from biomass
gasification. A stratified throatless downdraft gasifier was used to generate producer
gas with heating value of about 4-5 MJ m-3. Investigation has been done on a 2-layer
alumina balls packed bed PMB with first and second layer consist of 10 mm and 20
mm alumina balls respectively. The study was done at various equivalence ratios (Φ)
and heights of second layer packed bed (H). Flow rate of producer gas was kept
constant at 130 LPM whereas flow rate of air was varied to produce different
equivalence ratios.
Increase in both equivalence ratio and height of second layer packed bed
increase the maximum temperature and the volume of combustion zone. The
combustion region achieved the highest temperature between 1300 K and 1550 K for
all cases. CO emission generally decreases with equivalence ratio. NOx emission
increases significantly when packed bed height exceeds 140 mm. But for the case of
packed bed heights of 80 mm and 110 mm, it shows increasing CO emission near the
lean limit. The lowest recorded emissions from the PMB were 6 ppm and 230 ppm
for CO and NOx respectively. PMB with second layer height of 140 mm was found
to be the best height for the current setup that manages to operate with submerged
flame between the range of equivalence ratio of 0.33 and 0.71.
A cyclone burner (CB) was experimented and the results were compared with
the PMB for the same producer gas flow rate of 130 LPM. It produces lower
maximum temperature at about 1200 K with minimum emissions of CO and NOx at
4 ppm and 350 ppm respectively. It was found that PMB has better performance than
CB in general. A shell and tube heat exchanger was incorporated with the PMB for
hot air production yielding maximum thermal output of 7 kW. Lean combustion in
PMB generally yields better performance.
Description
Keywords
The performance of PMB fueled , producer gas from biomass gasification