Model Predictions for New Iron Ore Sintering Process Technology Based on Biomass and Gaseous Fuels

Abstract

In this paper a new technology for a compact iron ore sintering machine is analyzed. The compact sintering process is based on the massive injection of gaseous fuels and the solid fuel is only agglomerated fine charcoal obtained by biomass. The solid fuel used in this study is obtained by agglomeration of fine charcoal produced from elephant glass which has very short period for production and CO2 capture (less than 6 months in tropical climate). To overcome the lower heat supply into the combustion front of the sintering process the simultaneous injection of oxygen and gaseous fuel is proposed. The proposed methodology is to combine the solid fuel (agglomerated fines charcoal) and steelworks gases in a compact machine to enhance heat and mass transfer with high productivity (about 5 times the conventional large machine). A multiphase mathematical model based on transport equations of momentum, energy and chemical species coupled with chemical reaction rates and phase transformations is used to analyze the inner process parameters. A base case representing a possible actual industrial operation of the sintering machine is used in order to compare different scenarios of practicable operations which represents advanced operations techniques. The model was used to predict six cases of combined operation with biomass and fuel gas utilization: a) Scenario 01 and 02: Wind boxes inflow from N01-N10 of rich mixture of natural gas (NG) +Air +O2, b) Scenario 03 and 04: Wind boxes inflow from N01-N10 of rich mixture of coke oven gas (COG)+Air + O2, c) Scenario 05 and 06: Wind boxes inflow from N01-N10 of mixture of COG+BFG+Air+O2. The model predictions indicated that for all cases, 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 within a compact sintering machine (in this study was the scenario 05), which enhance the productivity keeping good inner temperature distribution which promotes formation of calcium ferrites of structural shape which confers adequate metallurgical properties for blast furnace sinter. This technology is also expected to decrease considerably the specific CO2 emissions, as demonstrated by scenarios simulated. It worthy to mention that, although the solid fuel considered in this work is produced from biomass the gas utilization is attractive due to decrease of the CO2 emissions and the gas mixtures can easily be obtained by using inner steelworks gas.