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Prediction of performance from PRB coal fired in utility boilers with various furnace and firing system arrangements / B. Chudnovsky in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 12 (Décembre 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 12 (Décembre 2010) . - 04 o. Titre : Prediction of performance from PRB coal fired in utility boilers with various furnace and firing system arrangements Type de document : texte imprimé Auteurs : B. Chudnovsky, Auteur ; A. Talanker, Auteur ; Y. Berman, Auteur Année de publication : 2011 Article en page(s) : 04 o. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Boilers  Coal  Furnaces  Heat  exchangers  Pulverised  fuels  Steam  power  stations Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The present regulatory requirements enforce the modification of the firing modes of existing coal-fired utility boilers and the use of coals different from those originally designed for these boilers. The reduction in SO2 and NOx emissions was the primary motivation for these changes. Powder river basin (PRB) coals, classified as subbituminous ranked coals, can lower NOx and SOx emissions from power plants due to their high volatile content and low sulfur content, respectively. On the other hand, PRB coals have also high moisture content, low heating value, and low fusion temperature. Therefore when a power plant switches from the designed coal to a PRB coal, operational challenges were encountered. A major problem that can occur when using these coals is the severe slagging and excess fouling on the heat exchanger surfaces. Not only is there an insulating effect from deposit, but there is also a change in reflectivity of the surface. Excess furnace fouling and high reflectivity ash may cause reduction in heat transfer in the furnace, which results in higher furnace exit gas temperatures (FEGTs), especially with opposite wall burners and with a single backpass. Higher FEGTs usually result in higher stack gas temperature, increasing the reheater spray flow and therefore decreasing the boiler efficiency with a higher heat rate of the unit. A successful modification of an existing unit for firing of PRB coals requires the evaluation of the following parameters: (1) capacities or limitations of the furnace size, (2) the type and arrangement of the firing system, (3) heat transfer surface, (4) pulverizers, (5) sootblowers, (6) fans, and (7) airheaters. In the present study we used a comprehensive methodology to make this evaluation for three PRB coals to be potentially fired in a 575 MW tangential-fired boiler. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] Prediction of performance from PRB coal fired in utility boilers with various furnace and firing system arrangements [texte imprimé] / B. Chudnovsky, Auteur ; A. Talanker, Auteur ; Y. Berman, Auteur . - 2011 . - 04 o. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 12 (Décembre 2010) . - 04 o. Mots-clés : Boilers  Coal  Furnaces  Heat  exchangers  Pulverised  fuels  Steam  power  stations Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The present regulatory requirements enforce the modification of the firing modes of existing coal-fired utility boilers and the use of coals different from those originally designed for these boilers. The reduction in SO2 and NOx emissions was the primary motivation for these changes. Powder river basin (PRB) coals, classified as subbituminous ranked coals, can lower NOx and SOx emissions from power plants due to their high volatile content and low sulfur content, respectively. On the other hand, PRB coals have also high moisture content, low heating value, and low fusion temperature. Therefore when a power plant switches from the designed coal to a PRB coal, operational challenges were encountered. A major problem that can occur when using these coals is the severe slagging and excess fouling on the heat exchanger surfaces. Not only is there an insulating effect from deposit, but there is also a change in reflectivity of the surface. Excess furnace fouling and high reflectivity ash may cause reduction in heat transfer in the furnace, which results in higher furnace exit gas temperatures (FEGTs), especially with opposite wall burners and with a single backpass. Higher FEGTs usually result in higher stack gas temperature, increasing the reheater spray flow and therefore decreasing the boiler efficiency with a higher heat rate of the unit. A successful modification of an existing unit for firing of PRB coals requires the evaluation of the following parameters: (1) capacities or limitations of the furnace size, (2) the type and arrangement of the firing system, (3) heat transfer surface, (4) pulverizers, (5) sootblowers, (6) fans, and (7) airheaters. In the present study we used a comprehensive methodology to make this evaluation for three PRB coals to be potentially fired in a 575 MW tangential-fired boiler. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]