ABSTRACT
This paper deals with optimization of coal combustion conditions to support selection a sustainable combustion technology and an optimal furnace and boiler design. A methodology for optimization of coal combustion conditions is proposed and demonstrated on the example of Bosnian coals. The properties of Bosnian coals vary widely from one coal basin to the next, even between coal mines within the same basin. Very high percentage of ash (particularly in Bosnian brown coal) makes clear certain differences between Bosnian coal types and other world coal types, providing a strong argument for investigating specific problems related to the combustion of Bosnian coals, as well as ways to improve their combustion behavior. In this work, options of the referent energy system (boiler) with different process temperatures, corresponding to the different combustion technologies; pulverised fuel combustion (slag tap or dry bottom furnace) and fluidized bed combustion, are under consideration for the coals tested. Sustainability assessment, based on calculation economic and environment indicators, in combination with common low cost planning method, is used for the optimization. The total costs in the lifetime are presented by General index of total costs, calculated on the base of agglomeration of basic economic indicators and the economic indicators derived from environmental indicators. So, proposed methodology is based on identification of those combustion technologies and combustion conditions for coals tested for which the total costs in lifetime of the system under consideration are lowest, provided that all environmental issues of the energy system is fulfilled during the lifetime. Inputs for calculation of the sustainability indicators are provided by the measurements on an experimental furnace with possibility of infinite variation of process temperature, supported by good praxis from the power plants which use the fuels tested and by thermal calculations of the different options (different temperature in the boiler furnace) of the referent energy system.
KEYWORDS
PAPER SUBMITTED: 2009-11-27
PAPER REVISED: 2010-03-22
PAPER ACCEPTED: 2010-05-26
THERMAL SCIENCE YEAR
2010, VOLUME
14, ISSUE
Issue 3, PAGES [715 - 727]
- Afgan, N. H., Multicriteria Indicators for Clean Air Technologies, UNESCO chair holder, Instituto Superior Tecnico, Lisbon, Portugal, Estoril, Portugal, 2000
- Wall, T. F., Juniper, L., Lowe, A., State-of-the-Art Review of Ash Behaviour in Coal-Fired Furnaces, ACARP Project C9055, The University of Newcastle, University Drive Callaghan, NSW, 2308 Australia, 2001
- Kazagi}, A., Smajevi}, I., Synergy Effects of Co-Firing of Wooden Biomass with Bosnian Coal, Energy, 34 (2009), 5, pp. 699-707, doi: 10.1016/j.energy.2008.10.007.
- Kazagi}, A., Smajevi}, I., Investigation of Coal Combustion Indicators by an Experimental Method, Proceedings on CD, 32nd, International Clearwater Coal Conference, Clearwater, Fla., USA, 2008
- Kazagi}, A., Smajevi}, I., Experimental Investigation of Ash Behavior and Emissions during Combustion of Bosnian Coal and Biomass, Energy, 32 (2007), 10, pp. 2006-2016,
- doi:10.1016/j.energy.2007.03.007
- Kazagi}, A., Investigation of Pulverised Combustion of Bosnian Coals Focused on Improvement Existing and Selection New Combustion Technologies in Coal-Based Power Plants (in Bosnian), Ph. D. thesis, Faculty of Mechanical Engineering, University of Sarajevo, Sarajevo, 2009
- Kupka, T., Zajac, K., Weber, R., Influence of Fuel Type and Deposition Surface Temperature on the Growth and Chemical and Physical Structure of Ash Deposit Sampled during Co-Firing of Coal with Sewage Sludge and Saw-Dust, Proceedings on CD, 8th International INFUB Conference, Vilamoura, Portugal, 2008
- Kupka, T., et al., Investigation of Ash Deposit Formation during Co-Firing of Coal with Sewage Sludge, Saw-Dust and Refuse Derived Fuel, Fuel, doi:10.1016/j.fuel.2008.01.024.
- Ots, A, Zelkowski, J., Determination of Fusion and Sintering Characteristics of Ashes, Proceedings, 5th International Conference Heat Engines & Environmental Protection, Balatonfüred, Hungary, 2001
- Zelkowski, J., Sturm, A., Mauritz, O., Combustion Property Characterization of Imported Coals by Indexes, VGB-PowerTech, Heft 10, 1998, pp. 83-87
- Maier, J., et al., Particle and Emission Behavior of Raw and Predried Lignite in a 20 kW and in a 500 kW Test Facility, Proceedings, 23rd International Conference on Coal Utilization & Fuel Systems, Clearwater, Fla., USA, 1998
- Smajevi}, I., Kazagi}, A., Evaluation of Ash Deposits during Experimental Investigation of Co-Firing of Bosnian Coal with Wooden Biomass, Proceedings, Advanced Fuels and Technology Portfolio in Thermal Power Plant Engineering, 40nt Conference of Thermal Power Plant Engineering, Dresden, Germany, 2008, Band 2, pp. 238-249
- Wolff, G. D., Lauxtermann, S., Kumar, R., Online Optimization of Hybrid Desalination Plants, Middle East Energy, September 2007, pp. 11-12, and Power Engineering International, December 2007/January 2008, pp. 47-48