Comportamiento de cenizas y su impacto en sistemas de combustión de biomasa
Palavras-chave:
Biomasa, Combustión, Cenizas, Cloro, CorrosiónResumo
La biomasa como combustible, además de proveer energía de manera renovable, decrece la dependencia del crudo importado y genera valor agregado para los países donde se desarrollan. El conocimiento del comportamiento del combustible es imprescindible para diseñar y operar equipos de manera segura y eficiente, en particular el conocimiento de los minerales que contenga ya que su ceniza jugará un papel importante en la dinámica del sistema de generación. A través del conocimiento de la composición química y propiedades físicas de la ceniza es posible predecir la tendencia a formar depósitos en componentes de caldera y su potencial para causar corrosión, erosión y abrasión. El comportamiento de las cenizas en el sistema es altamente dependiente del combustible, en particular cuando se trata de desechos industriales o cultivos energéticos. Estos combustibles tienen mayor contenido de minerales, en particular Sodio Potasio, Fósforo y Cloro, alto contenido de cenizas con bajo punto de fusión y alto potencial corrosivo. Este trabajo se concentra en las características de la ceniza derivada de la combustión de biomasa, con particular atención en la química de transformaciones a alta temperatura y su efecto sobre las instalaciones. Se hace énfasis en los posibles problemas que ocurren cuando se adecúan las tecnologías de quemado de madera a cultivos energéticos, por ejemplo, de manera de evitar fallas catastróficas. Se concluye con recomendaciones sobre el manejo, control y prevención de problemas asociados a cenizas.
Downloads
Referências
[2] Obernberger, I. and Biedermann, F. Fractionated heavy metal separation in Austrian biomass grate-fired combustion plants approach, experiences, results Ashes and Particulate Emissions from Biomass Combustion Thermal Biomass Utilization series, 1998, vol. 3, BIOS, Graz,
Austria, dbv-Verlag.
[3] Obernberger, I., Dahl, J. and Brunner T. Formation, composition and particle size distribution of fly ashes from biomass combustion plants Proceedings of the 4th Biomass Conference of the Americas, September 1999, Oakland, CA, Elsevier Science Ltd., Oxford, UK,
pp1377–1385
[4] Kauppinen, E., Lind, T., Kurkela, J., Latva-somppi, J. and Jokiniemi, J. Ash particle formation mechanisms during pulverised and fluidised bed combustion of solid fuels, Ashes and Particulate Emissions from Biomass Combustion, vol. 3 of Thermal Biomass Utilization series,1998, BIOS, Graz, Austria, dbv-Verlag.
[5] Lind, T., Valmari, T., Kauppinen, E., Maenhaut, W. and Huggins, F. Ash formation and heavy metal transformations during fluidised bed combustion of biomass Ashes and Particulate Emissions from Biomass Combustion, volume 3 of Thermal Biomass Utilization series, 1998,
BIOS, Graz, Austria, dbv-Verlag
[6] Brunner, T., Obernberger, I., Brouwers J. J. H. and Preveden, Z. Efficient and economic dust separation from flue gas by the rotational particle separator as an innovative technology for biomass combustion and gasification plants, Proceedings of the 10th European Bioenergy Conference, June 1998, Würzburg, Germany, CARMEN, Rimpar, Germany
[7] Materials Characterization Laboratory, SEM photos, www.pmetlabservices.com
[8] Wood fuels Handbook, 2008
[9] Van Loo, S and Koppejan, J. Handbook of Combustion and Co-Firing, 2010
[10] CEN/TS 14961 – 2005 Technical Specification - Solid Biofuels
[11] Francescato, V – Vitis energetic, 2007
[12] Baxter, L. L., Miles, T. R., Miles, T. R. jr., Jenkins, B. M. Milne, T., Dayton, D., Bryers, R. W. and Oden, L .L. ‘The behaviour of inorganic material in biomass-fired power boilers: Field and laboratory experiences’, Fuel Processing Technology, 1998, vol 54, pp47–78
[13] Melissari, B. Tecnologías de Quema de Biomasa en el Uruguay, Memoria de Trabajos de Difusión Científica y Técnica, ISSN 1510-7450, Nº. 9, 2011, pags. 55-66
[14] Obernberger, I., Brunner, T. and Joller, M. Characterisation and formation of aerosols and fly ashes from fixed-bed biomass combustion, in Nussbaumer, T. (ed.), Aerosols from Biomass Combustion, International Seminar, 27 June 2001 in Zurich, 2001, Verenum, Switzerland.
[15] Obernberger, I. and Brunner, T. ‘Fly ash and aerosol formation in biomass combustion processes – an introduction’, Aerosols in Biomass Combustion, 2005, vol 6 in Thermal Biomass Utilization Series, BIOS Bioenergy Systeme, Graz, Austria
[16] Valmari, T. Potassium behaviour during combustion of wood in circulating fluidised bed power plants’, VTT Publication, 2000, 414
[17] Bain, R. L., Overend, R. P. and Craig, K. R. Biomass-fired power generation, Fuel Processing Technology, 1998, vol 54, pp1–16
[18] Backman, R., Skrifvars, B.-J. and Yrjas, P. The influence of aerosol particles on the melting behaviour of ash deposits in biomass-fired boilers, Aerosols in Biomass Combustion, 2005, Graz, Austria
[19] Raask, E. Mineral Impurities in Coal Combustion: Behavior, Problems, and Remedial Measures, Hemisphere Publishing, 1985, New York
[20] Neilsen, H. P., Frandsen, F. J., Dam-Johansen, K. and Baxter, L. L. The implications of chlorine-associated corrosion on the operation of biomass-fired boilers Prog. Energy and Combustion Science, 2000, vol 26, pp283–298
[21] Henriksen, N., Montgomery, M. and Larsen, O. H. High temperature corrosion in biomassfired boilers, VDI-Berichte, 2002, No. 1680
[22] Baxter, L. L., Tree, D., Fonseca, F. and Lucas, W. Biomass combustion and cofiring issues overview: Alkali deposits, fly ash, NOx/SCR impacts, International Conference on Co-utilisation of Domestic Fuels, feb. 2003, Gainesville, FL.
[23] Riedl, R., Dahl, J., Obernberger, I. and Narodoslawsky, M. Corrosion in fire tube boilers of biomass combustion plants, Proceedings of the China International Corrosion Control Conference, 1999, Beijing.
[24] Montgomery, M., Karlsson, A. and Larsen, O. H. Field test corrosion experiments in Denmark with biomass fuels. Part 1: Straw firing, Materials and Corrosion, 2002, vol 53, pp121–131.
[25] Montgomery, M. and Larsen, O. H. Field test corrosion experiments in Denmark with biomass fuels. Part 2: Co-firing of straw and coal, Materials and Corrosion, 2002, vol 53, pp185–194.
[26] Parthiban, K.K. Chlorine induced high temperature superheater corrosion in biomass power plants Venus Energy Audit System, 2006.