ESTUDO NUMERO DA RECICLAGEM DE CO2 NA ZONA DE COMBUSTÃO DO ALTO FORNO
NUMERICAL STUDY OF CO2 RECYCLING INTO THE COMBUSTION ZONE OF THE BLAST FURNACE
Castro, José Adilson de; Baltazar, Anderson Willian de S.
http://dx.doi.org/10.4322/tmm.00601003
Tecnol. Metal. Mater. Min., vol.6, n1, p.13-18, 2009
Resumo
Altos fornos produzem gases com poder calorífico relativamente elevado que são comumente utilizados no interior da usina. Entretanto, o gás rico em CO2 não tem aplicação sendo descartado na atmosfera. Portanto, é desejável que a geração especifica de gás de alto forno seja minimizada, pois contribuiria para a diminuição do aquecimento global. Neste estudo, é utilizado um modelo total do alto forno para avaliar a possibilidade de injeção de CO2 nas ventaneiras utilizando-se do excesso de entalpia nessa região do alto forno, visando incrementar as reações de gás d’agua e solution loss, gerando gás redutor para o processo. O modelo total do alto forno é baseado em equações de transporte de momentum, energia e espécies químicas em sistemas multifásicos, a saber: gás, sólidos, gusa, escória e fases pulverizadas. São selecionados quatro casos de análise com injeção de CO2 e o enriquecimento em oxigênio do sopro é ajustado visando operação estável do processo. Resultados de simulação indicam que a produtividade pode ser aumentada em torno de 15% devido ao efeito combinado de alto consumo de PCI, via solution loss, e aumento de geração do gás redutor no forno.
Palavras-chave
Altos-fornos, Reciclagem, Dióxido de carbono, Simulação computacional
Abstract
The blast furnaces process produces gases with relative high calorific value, which is commonly used in the steelmaking facilities. However, CO2 rich gas has not application and it is desirable to minimize its emission due to global warming effects. In this investigation, a total model of the blast furnace is used to analyze the injection of CO2 into the blast furnace tuyeres promoting water shift reaction and solution loss, which, in turn, generates reducing gas to the blast furnace process. The total blast furnace model is based on transport equations of momentum, energy and chemical species for solids, gas, hot metal, slag and pulverized phases. Four cases are selected with CO2 recycling and blast volume together with oxygen enrichment adjustment in order to keep smooth operation. For the cases of high CO2 injection burden distribution is changed aiming at promoting better gas flow conditions. Simulated results indicate that productivity could be increased around 15% due to the combined effect of higher consumption on PCI via solution loss and higher reducing gas generation on the lower part of the furnace.
Keywords
Blast furnace, Recycling, Carbon dioxide, Computational simulation
Referências
1 NOGAMI, H.; YAGI, J.; KITAMURA, S.; AUSTIN P.R. Analysis on material and energy balances of iron making systems
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2 ANDAHAZY, D.; LOFFLER, G.; WINTER, F.; FEILMAYER, C.; BURGLER, T. 2005, Theoretical analysis on the injection of H2, CO, CH4 rich gases into the blast furnace. ISIJ International, v. 45, n. 2, p. 166-74, Feb. 2005.
3 YAGI, J. Mathematical modeling of the flow of four fluids in a packed bed. ISIJ International, v. 33, n. 6, p. 619-39, June 1993.
4 AUSTIN, P.R.; NOGAMI, H.; YAGI, J. A mathematical model for blast furnace reactions analysis based on the four fluid model. ISIJ International, v. 37 n. 8, p. 748-55, Aug. 1997.
5 CASTRO, J.A.; NOGAMI, H.; YAGI, J. Numerical analysis of multiple injection of pulverized coal, prereduced iron ore and flux with oxygen enrichment to the blast furnace. ISIJ International, v. 41, n. 1, p.18-24, Jan. 2001.
6 CASTRO, J.A.; NOGAMI, H.; YAGI, J. Numerical investigation of simultaneous injection of pulverized coal and natural gas with oxygen enrichment to the blast furnace. ISIJ International, v. 42, n. 11, p. 1203-11, Nov. 2002.
7 CASTRO, J.A.; NOGAMI, H.; YAGI, J. Transient mathematical model of blast furnace based on multi-fluid concept, with application to high PCI operation. ISIJ International, v. 40, n. 7, p. 637-46, Jul. 2000.
2 ANDAHAZY, D.; LOFFLER, G.; WINTER, F.; FEILMAYER, C.; BURGLER, T. 2005, Theoretical analysis on the injection of H2, CO, CH4 rich gases into the blast furnace. ISIJ International, v. 45, n. 2, p. 166-74, Feb. 2005.
3 YAGI, J. Mathematical modeling of the flow of four fluids in a packed bed. ISIJ International, v. 33, n. 6, p. 619-39, June 1993.
4 AUSTIN, P.R.; NOGAMI, H.; YAGI, J. A mathematical model for blast furnace reactions analysis based on the four fluid model. ISIJ International, v. 37 n. 8, p. 748-55, Aug. 1997.
5 CASTRO, J.A.; NOGAMI, H.; YAGI, J. Numerical analysis of multiple injection of pulverized coal, prereduced iron ore and flux with oxygen enrichment to the blast furnace. ISIJ International, v. 41, n. 1, p.18-24, Jan. 2001.
6 CASTRO, J.A.; NOGAMI, H.; YAGI, J. Numerical investigation of simultaneous injection of pulverized coal and natural gas with oxygen enrichment to the blast furnace. ISIJ International, v. 42, n. 11, p. 1203-11, Nov. 2002.
7 CASTRO, J.A.; NOGAMI, H.; YAGI, J. Transient mathematical model of blast furnace based on multi-fluid concept, with application to high PCI operation. ISIJ International, v. 40, n. 7, p. 637-46, Jul. 2000.
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