8th International Congress on Science and Technology of Ironmaking - ICSTI 2018

The demand for increasing energy efficiency is one of the global megatrends of our time. Although the steel industry suffers from a volatile economic environment, steel plant operators are interested to find opportunities for sustainable cost reduction. Steel mills are trying to cut electrical power and energy costs as these are among the biggest cost factors that can be influenced. The product cooler of sinter plants offers an excellent possibility to recover up to 50 - 80 kWh thermal energy per ton of sinter by using either a steam or hot water boiler. The recovered energy can be used to produce electrical energy or be used for instance for the SCR (Selective Catalytic Reduction) – Technology, which is applied to reduce the nitrous oxides in the primary sinter off-gas in conjunction with Primetals’ MEROS® technology. The SCR technology requires typically an elevated reaction temperature and can be therefore an efficient consumer for the generated waste heat and contributes to the efficient gas cleaning of the sinter off gas. Furthermore significant proportion of the generated blast furnace (top-) gas with the inherent pressure/thermal energy is unutilized since the blast furnace gas is just throttled by means a throttling element to reach the pressure of low pressure gas network. In order to recover this energy, Primetals Technologies offers its TRT (Top-Gas Recovery Turbine) solution that includes a gas expander and the required auxiliaries downstream of a widely used wet or innovative dry dedusting technology (MERIM®). In the energy generation process from blast furnace gas approximately 30 – 40 kWh of electrical energy per ton of hot metal is possible with low maintenance costs. This electricity can be used for internal usage within the steelworks or for external sales to the power grid thereby reducing CO2 emissions. One of the global trends that are constantly challenging the iron and steel industry is related to the generation of fines, slurry, sludge and scales, summed up as ferrous by-products. The recycling of those by-products is commonly practiced in many steel plants. These materials normally cannot be used directly in the primary processes. The most common application is to add ferrous by-products which are suitable concerning chemical composition and grain size distribution to the sinter mix. Primetals will present latest developments in the field of cold briquetting of ferrous by-products and of coal briquetting . Giving examples and results of executed project(s) of cold briquettes directly fed to the DR shaft, and other solutions for integrated steel mills. Coal briquetting on the other hand is based on coal fines which often originate from wear during coal transport from mine to plant. These fines can be used to produce briquettes designed either for the use in a smelting reduction process (COREX®/FINEX®) or for enhanced coke oven operation in the traditional blast furnace route.