Vagner Silva Guilherme

Analysis by multiphase multicomponent model of iron ore sintering based on alternative steelworks gaseous fuels

Abstract This paper presents the numerical simulation of the technology of gaseous fuel utilisation for iron ore sintering. The proposed methodology is to partially replace the solid fuel by steelworks gases. A multiphase mathematical model based on transport equations of momentum, energy and chemical species coupled with chemical reaction and phase transformations was proposed to analyse temperature distributions of the process. A base case of actual industrial operation of a large sintering machine was monitored with thermocouples inserted into the sinter bed to validate the model. The model was used to predict four cases of fuel gas utilisation: feeding from N01 to N15 wind boxes with blast furnace gas (BFG); natural gas (NG); coke oven gas (COG); and a 50–50 mixture of BFG and COG. The model predictions indicated that for all cases the sintering zone is enlarged and the solid fuel consumption could be decreased.

Utilização de gás de coqueria na sinterização de minério de ferro

In order to study new alternatives for the sintering, the use of gaseous fuels has provided a significant reduction in the consumption of solid fuels, and also propitiates better quality control of physical and metallurgical sinter properties. In this study, a sintering model is proposed to evaluate the injection of coke oven gas in the process. We analyze five cases of coke oven gas injection always seeking a stable operational process. The simulation results indicate a lower consumption of solid fuel with the injection of coke oven gas and an increase of the combustion front. As a result, this increased the fraction of calcium silicates, which consequently improved the reducibility and also reduced the amount of CO2 in the output gas.

Iron Ore Sintering Process Based on Alternative Gaseous Fuels from Steelworks

This paper deals with the numerical simulation of the new technology of gaseous fuel utilization on the sintering process of iron ore. The proposed methodology is to partially replace the solid fuel(coke breeze) by steelworks 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. 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) 2% of the wind boxes inflow from N01-N15 wind boxes of natural gas(NG), b) same condition with coke oven gas(COG), c) same condition with blast furnace gas(BFG) and d) mixture of 50% COG and 50% BFG. The model predictions indicated that for all cases, except only BFG, the sintering zone is enlarged and the solid fuel consumption is decreased about 8kg/t of sinter product. In order to maximize the steelworks gas utilization it is recommended the use of mixture of COG and BFG with optimum inner temperature distribution

Displacement of the Ingnition Furnace in the Iron Ore Sintering with Re-Circulation of Waste Gases

In search of new technologies for the iron ore sintering process, the re-circulation of waste gases in the process can provide some advantages in relation to the conventional process. For such study, a sintering multi-phase model was used for the assessment of the re-circulation of waste gases in the process. Five cases of re-circulation of waste gases in the sintering process were analyzed, always aiming at a stable operation in the process. The results of the simulation indicate an enlargement of the combustion front with the re-circulation of the waste gases and the possibility of existing a reduction of the solid fuel consumption. As a result, there was an increase of the calcium-silicate fraction, providing a sinter reducibility improvement, apart from the reduction of the emission of CO2 and PCDD/Fs in the sinter machine.

Predictions of PCDD/F, SO x , NO x , and Particulates in the Iron Ore Sintering Process of Integrated Steelworks

This chapter is focused on the multiphase multicomponent model development and prediction of common hazardous compounds produced during the industrial iron ore sintering process within an integrated steelworks. The iron ore sintering process is a key technology in the steel industry due to its possibility of recycling waste solids or powders internally produced during the raw materials handling or subsequent process of steel production. However, this process is also recognized as one of the most critical unit with regard to the polychlorinated dioxins and furans (PCDD/F) emissions. In addition, as fossil fuels are used, the emissions of SOx and NOx are significant and must be strictly controlled. The process is dynamic and involves the cross flow of gas through the bed which can carry the fine particles. The outlet gas treatment involves the cleaning with electrostatic precipitator and filter bags. New technologies, however, have been introduced in order to treat PCDD/F and SOx–NOx compounds, which introduce significant increase in the cost of the production. New process concepts and technologies have been proposed such as gas recycling, fuel gas injection, and biomasses fuels. However, testing these technologies are expensive. In this context, comprehensive mathematical models based on transport phenomena are efficient tools to study and indicate new possibilities for designing operational conditions as well as resizing the machines for minimizing the hazardous emissions. In this chapter, the model principles and analysis cases are presented and discussed. The impacts of four technological proposal on the hazardous emissions of PCDD/F, NOx, SOx, and particulates are analyzed, as follows: (a) effect of fuel gas injection; (b) effect of gas recycling and oxygen injection; and (c) effect of using biomass and biogas replacing the fossil fuel (coke breeze). The analysis is carried out comparing the actual operation of the industrial iron ore sintering machine with the new concepts proposed based on their specific hazardous emissions.