Influence of NH/sub 3/ addition on the NO emissions from a coal-fired fluidised bed combustor

Conference · Fri Jan 01 04:00:00 EST 1982 · Symp. (Int.) Combust., (Proc.); (United States)

OSTI ID:5756899

Hampartsoumian, E; Gibbs, B M

The feasibility of ammonia injection directly into a fluidised-bed coal combustor for the control of NO emissions by selective noncatalytic homogeneous reactions was studied. Experimental runs were carried out using a bituminous coal and a low volatile anthracite fired in a 0.3 m square combustor. The ammonia was either premixed with the combustion air or directed horizontally across the fluidising air flow through injectors designed to ensure a uniform distribution of NH/sub 3/ over the total width of the combustion chamber. The combustor was operated over an excess air range of -20 to 120% and bed temperatures of 770 to 910/sup 0/ C. Results showed that for NH/sub 3/ injection at the optimum location just above the bed surface, a 30 to 50% reduction in the NO levels in the exit flue was attainable for a NH/sub 3//NO molar ratio of 2 to 4 and a bed temperature of around 825/sup 0/ C. A maximum reduction of 75% was possible by using excess ammonia, but at the cost of increased ammonia emissions. Premixing the ammonia with the combustion air initially resulted in an increase in the NO levels, whilst at higher NH/sub 3/ flows, marginal reductions in the NO emission were observed. The presence of excess air was found to lower the extent of NO removal, with optimum reductions occurring at an oxygen concentration of around 3 to 5% at the point of injection. Varing the bed temperature in the range 770 to 910/sup 0/C did not significantly influence the extent of NO reduction and it is thought that the reductions achieved, especially at the lower bed temperatures, can partly be accounted for by the presence of unburnt volatile fragments (e.g. H/sub 2/, CH/sub 4/) which are known to enhance the NO/NH/sub 3/ reaction.

• Research Organization: Univ. of Leeds, England
• OSTI ID: 5756899
• Report Number(s): CONF-820801-
• Conference Information: Journal Name: Symp. (Int.) Combust., (Proc.); (United States)
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
014000* -- Coal
Lignite
& Peat-- Combustion
42 ENGINEERING
421000 -- Engineering-- Combustion Systems
500200 -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
AIR POLLUTION CONTROL
AMMONIA
CARBONACEOUS MATERIALS
CHALCOGENIDES
CHEMICAL REACTIONS
COAL
COMBUSTION
COMBUSTION PRODUCTS
COMBUSTORS
CONTROL
ENERGY SOURCES
FLUIDIZED-BED COMBUSTION
FLUIDIZED-BED COMBUSTORS
FOSSIL FUELS
FUELS
HYDRIDES
HYDROGEN COMPOUNDS
MATERIALS
NITRIC OXIDE
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NITROGEN OXIDES
OXIDATION
OXIDES
OXYGEN COMPOUNDS
POLLUTION CONTROL
THERMOCHEMICAL PROCESSES