Abstract
Emissions of NOx and SO2 were monitored in the presence of ammonia liquor in a 0.09 m2 and 2 m high stainless-steel fluidized-bed combustor. Experiments were carried out at 2 m/s fluidizing velocity, 40% excess air, and 870 °C bed temperature. Ammonia liquor with 7% ammonia by weight was injected into the freeboard of the combustor 52 cm above the distributor through a water-cooled injector. A 65 : 34 primary/secondary air ratio was maintained throughout the investigation. Approximately 70% of NO and 20% of SO2 was reduced at an NH3/NO molar ratio of 2 : 1, respectively. However, a higher reduction in SO2 emissions (62%) was achieved at a very high NH3/NO molar ratio of 7 : 1. These experiments showed that ammonia addition did have a significant effect in SO2 reduction if injected in an excess amount. The injection of ammonia liquor combined with staged combustion was found to be very effective in reducing NOx emissions. A reduction of about 50% was achieved at an NH3/NO molar ratio of 0.6 : 1 which is also coupled with a very low level of ammonia in the flue.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Barnes, J. P.: 1988, ‘Abatement of Nitric Oxide Emissions from a Coal Fired Fluidized-Bed Combustor', Ph. D. Thesis, Dept. of Fuel and Energy, Univ. of Leeds, U.K.
Dean, A. M.: 1985, United States Patent No. 4507269.
Jonke, A. A. et al.: 1972, ‘Pollution Control Capabilities of FBS', AIChE Symp. Series, No 126, 68, 241–251.
Khan, W. Z. and Gibbs, B. M.: 1991, ‘Simultaneous Removal of NOx and SO2 by Limestone in a Fluidized Combustor', 11th Int. Conf. on Fluidized-Bed Combustion, Montreal, Canada, pp. 99–106.
Khan, W. Z. and Gibbs, B. M.: 1996, ‘Reduction of SO2 Emissions by Ammonia Gas during Unstaged Combustion', Environ. Monit. Assess. 40, 157–170.
Lyon, R. K.: 1975, ‘Method for the Reduction of the Concentration of NO in the Combustion Effluent Using Ammonia', US Patent No. 390054.
Lyon, R. K.et al.: 1979a, ‘The Thermal DeNox Process', IChE Symp. Series No. 57.
Lyon, R. K.: 1979b, ‘Thermal DeNOx: How it Works', Hydrocarbon Process 58, 109–112.
Lucas, D. and Brown, N. J.: 1983, ‘The Influence of Thiophene on the Selective Reduction of NO by NH3', Combustion and Flame 49(1–3), 283–288.
Lyon, R. K. and Hardy, J. E.: 1986, ‘Discovery and Development of the Thermal DeNOx Process', Ind. Eng. Chem. (Fundamental) 25, 19–24.
Lyon, R. K. et al.: 1987, ‘Thermal DeNOx', Environ. Sci. Technol. 21(3), 231–236.
Muzio, L. J. et al., 1977, ‘Gas Phase Decomposition of NO in Combustion Products', 16th Symp. (Int.) on Combustion, The Combustion Institute.
Muzio, L. J., Maloney, K. L. and Aranad, J. K.: 1978, ‘Reaction of Ammonia with NO in Coal Derived Combustion Product', 17th Symp. (Int.) on Combustion, Leeds, U.K., The Combustion Institute, pp. 86–89.
Ritz, J. et al.: 1989, ‘Reduction of NOx Emissions by Fuel Staging, Effects of Ammonia Addition to the Reburn Fuel', Joint Meeting of the British and French Section of the Combustion Institute, Rouen, France.
Shale, C. C.: 1971, ‘Removal of Sulphur and Nitrogen Oxides from Stack Gases by NH3', AIChE Symp Series No. 115, 52–58.
Slack, A. V,: 1979, ‘Status of NOx Removal from Combustion Gases', 3rd Int. Conf. on the Control of Sulphur and Other Gaseous Emissions Salford, IChE Symp. Series No. 57.
Tatebayashi, J. et al.: 1980, ‘Simultaneous NOx and SO2 Emissions Reduction with Fluidized-Bed Combustion', 6th Int. Conf. on FBC, Atlanta, USA, pp. 986–995
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Khan, W.Z., Sibtain, F.S. & Gibbs, B.M. Combined Non-Catalytic Reduction of NOx and SO2 by Ammonia Liquor during Staged Fluidized-Bed Combustion. Environ Monit Assess 57, 45–58 (1999). https://doi.org/10.1023/A:1005940728499
Issue Date:
DOI: https://doi.org/10.1023/A:1005940728499