Modellering av järnnmalmsreduktion baserade på Rist-diagrammet

Validerat; 20101217 (root

Understanding of Blast Furnace Performance with Biomass Introduction

The blast furnace still dominates the production and supply of metallic units for steelmaking. Coke and coal used in the blast furnace contribute substantially to CO2 emissions from the steel sector. Therefore, blast furnace operators are making great efforts to lower the fossil CO2 emissions and transition to fossil-free steelmaking. In previous studies the use of pre-treated biomass has been indicated to have great potential to significantly lower fossil CO2 emissions. Even negative CO2 emission can be achieved if biomass is used together with carbon capture and storage. Blast furnace conditions will change at substantial inputs of biomass but can be defined through model calculations when using a model calibrated with actual operational data to define the key blast furnace performance parameters. To understand the effect, the modelling results for different biomass cases are evaluated in detail and the overall performance is visualised in Rist- and carbon direct reduction rate (CDRR) diagrams. In this study injection of torrefied biomass or charcoal, top charging of charcoal as well as the use of a combination of both methods are evaluated in model calculations. It was found that significant impact on the blast furnace conditions by the injection of 142 kg/tHM of torrefied biomass could be counteracted by also top-charging 30 kg/tHM of charcoal. With combined use of the latter methods, CO2-emissions can be potentially reduced by up to 34% with moderate change in blast furnace conditions and limited investments

Forestry meets Steel : A system study of the possibility to produce DRI (directly Reduced Iron) using gasified biomass

The main production of primary Iron from ore is now made by reduction using fossil reductants, either by producing hot metal in the blast furnace process or as directly reduced iron with natural gas as most common reductant. The climate gas impact would be improved if at least part of the reductants could be produced from Biomass. One possibility could be to use gasified Biomass to produce DRI (Directly Reduced Iron). This is studied in a cooperative project where LTU, MEFOS, ETC and five industries in the areas forestry &amp; pulp, mining, iron and gas are involved. The investigation is made in four parts where the first one is on the supply of biomass. A large amount of Biomass has to be delivered into a single site to exchange a large amount of fossil reductant. Also, forestry by-products should be used as most of the round wood is reserved for other uses. Harvesting, logistics and economics are considered. The second part is on the gasification of the biomass, where the aim is to use to produce hot gas that can be used directly. Pilot experiments are carried out using oxygen in an entrained flow gasifier. The third part is on the metallurgical processes, where reduction tests are carried out with gas that can be produced in the gasifier. The limitations of the gas content are studied as well as the effect on DRI. Also the suitability of the DRI product is evaluated. The fourth part of the project uses process integration to model the whole process chain. The results from the other project parts are used to build the system model. It is then used for technical economic optimization the whole system harvesting-transport-gasifier-direct reduction-use of DRI. The first use of the system model has been to find the best supply road (harvesting, pretreatment and transport) for a chosen production case The simulations indicated that the supply of residuals is possible but will need material from a large part of the north Sweden wood area, and that a relatively large amount of gas recirculation is needed. The continuing work is focused on further development of the optimization tool and the use of it for more extensive studies of the trade-off between parameters of metallurgy, gasification and supply. The result can be important for evaluation of future industrial applications. It could also help in understanding the effect of governmental control instruments. The paper will mainly focus on the process integration study.Godkänd; 2015; 20150811 (cargri)</p

Low CO2 ironmaking in the blast furnace : Roheisenerzeugung im Hochofen mit niedrigen CO2 Emissionen

The steel industry contributes to the global emissions of fossil CO2 by ~ 7 %, mainly related to coal and coke used in the BF. At the same time the BF is, and will be in a foreseeable future, the most energy efficient method for ore based hot metal production. Several R&amp;D teams have investigated concepts to minimise CO2 emission as e.g. the ULCOS top gas recycling BF, high injection of H2, use of bio-mass products and HBI. In this paper these different options, and in some cases combination of these are analysed relative the BF conditions and their possible impacts on fossil CO2 emission are compared.Validerad;2017;Nivå 2;2017-10-05 (andbra)</p