Título

ANALYSIS OF PCDD AND PCDF EMISSIONS ON THE IRON ORE SINTERING PROCESS BASED ON ALTERNATIVE GASEOUS FUELS FROM STEELWORKS

ANALYSIS OF PCDD AND PCDF EMISSIONS ON THE IRON ORE SINTERING PROCESS BASED ON ALTERNATIVE GASEOUS FUELS FROM STEELWORKS

Autoria

Castro, Jose Adilson de; Guilherme, Vagner Silva; França, Alexandre Bôscaro; Sazak, Yasushi; Jun-ichiroYagi.,

DOI

10.5151/2594-357X-22097

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Resumo

Recently the technology of gas utilization on the iron ore sintering process has been proposed as alternative for reducing the environmental impact and improvements on the sinter quality with lower return(<5mm). This paper deals with the numerical simulation of this new technology in order to evaluate the emissions of poly chlorinated di-benzene dioxin (PCDD) and Poly Chlorinated di-benzene furan (PCDF). The proposed methodology is to partially replace the solid fuel(coke breeze) by steelworks gases such as coke oven gas (COG), blast furnace gas (BFG) and synthetic gas obtained by mixture of these gases. A multiphase mathematical model based on transport equations of momentum, energy and chemical species coupled with chemical reaction rates and phase transformations is proposed to analyze the inner process parameters and the rates of PCDD and PCDF formation. A base case representing the actual industrial operation of a large sintering machine is used with thermocouples inserted into the sintering bed to record the inner bed temperatures and compare with model predictions in order to obtain model validation and parameters adjustment. Good agreement of the temperature pattern was obtained for the base case and thus, the model was used to predict four cases of fuel gas utilization: a) 4% of the wind boxes inflow from N01-N12 wind boxes COG, b) same condition with BFG, c) same condition with 50% COG and 50% BFG and d) mixture of 25% COG and 75% BFG. The model predictions indicated that for all cases, except only BFG, the sintering zone is enlarged and the solid fuel consumption is decreased. In order to maximize the steelworks gas utilization it is recommended the use of mixture of COG and BFG with optimum inner temperature distribution. For all cases of gas utilization the PCDD and PCDF emissions decreased.

 

Recently the technology of gas utilization on the iron ore sintering process has been proposed as alternative for reducing the environmental impact and improvements on the sinter quality with lower return(<5mm). This paper deals with the numerical simulation of this new technology in order to evaluate the emissions of poly chlorinated di-benzene dioxin (PCDD) and Poly Chlorinated di-benzene furan (PCDF). The proposed methodology is to partially replace the solid fuel(coke breeze) by steelworks gases such as coke oven gas (COG), blast furnace gas (BFG) and synthetic gas obtained by mixture of these gases. A multiphase mathematical model based on transport equations of momentum, energy and chemical species coupled with chemical reaction rates and phase transformations is proposed to analyze the inner process parameters and the rates of PCDD and PCDF formation. A base case representing the actual industrial operation of a large sintering machine is used with thermocouples inserted into the sintering bed to record the inner bed temperatures and compare with model predictions in order to obtain model validation and parameters adjustment. Good agreement of the temperature pattern was obtained for the base case and thus, the model was used to predict four cases of fuel gas utilization: a) 4% of the wind boxes inflow from N01-N12 wind boxes COG, b) same condition with BFG, c) same condition with 50% COG and 50% BFG and d) mixture of 25% COG and 75% BFG. The model predictions indicated that for all cases, except only BFG, the sintering zone is enlarged and the solid fuel consumption is decreased. In order to maximize the steelworks gas utilization it is recommended the use of mixture of COG and BFG with optimum inner temperature distribution. For all cases of gas utilization the PCDD and PCDF emissions decreased.

Palavras-chave

Sintering; Modeling; Fuels; Multiphase flow.

Sintering; Modeling; Fuels; Multiphase flow.