COURSE50 (CO2 ultimate reduction in steelmaking process by innovative technology for Cool Earth 50) carried out COG and reformed COG (RCOG) injection operation trials at LKAB's experimental blast furnace in Luleå in cooperation with LKAB and Swerea MEFOS. Operation trials were successfully carried out. Input of C in both COG and RCOG injection periods decreased comparing the base period, because of increase in H2 reduction instead of C direct reduction that is a huge endothermic reaction. However poor penetration depth of injected gas from shaft tuyere made furnace efficiency worse. Hot top gas injection increased temperature of top gas and upper part of the furnace. Efficiency of hot top gas injection was not clear as sinter degradation did not occur in the base period.KEY WORDS: COURSE50; experimental blast furnace; blast furnace; CO2 emission; H2; COG; reformed COG; injection; hot top gas; sinter degradation. PrefaceCOURSE50 (CO2 ultimate reduction in steelmaking process by innovative technology for Cool Earth 50) is a national project for development of technologies for environmentally harmonized steelmaking process to achieve drastic CO2 emissions reduction in steel industry. Main targets of COURSE50 project are development of technologies to reduce CO2 emissions from blast furnace and development of technologies to capture, separate and recover CO2 from blast furnace gas. CO2 reduction technology from blast furnace consists of research of control reactions for reducing iron ore with hydrogenous reducing agents such as coke oven gas (COG) or reformed COG (RCOG). RCOG is amplified its hydrogen content in COG by utilizing newly developed catalyst and unused waste heat. Also a technology to produce high strength and high reactivity coke for reduction with hydrogen is under development.RCOG will be injected to the blast furnace through tuyeres located at lower part of the shaft of blast furnace, and COG will be injected through blast tuyeres to utilize CH4 combustion.Amount of O2 enrichment to the hot blast air has to be increased when COG is injected to the blast tuyere to maintain the flame temperature constant to compensate for heat of decomposition of hydrocarbon. It results in decrease in upper part temperature and decreased upper part temperature prolongs the residence time for sinter where disintegration is promoted. In addition, H2 may promote sinter deterioration. To prohibit prolonged residence time for sinter at low temperature range, top gas is partly combusted is injected in the upper shaft for temperature control. We call it hot top gas injection in this article.Basic and remarkable results are conducted through various laboratory tests and mathematical model calculation in COURSE50 project.3,4) H2 in COG or RCOG is expected to react with ferrous material very fast and to replace C as reducing agent of blast furnace.However, reaction in the blast furnace is much complicated because it is dominated by burden and gas distribution

A high CSR coke was tested in the LKAB's Experimental Blast Furnace (EBF) at Luleå. The evolution of physical and chemical properties of the centre-line coke samples were analysed by Light Optical Microscopy (LOM), BET N 2 absorption and SEM/XRF/XRD. Alkali distribution in the EBF cokes was examined by XRF/SEM and EDS. Thermo Gravimetric Analysis (TGA) was used to measure isothermal and nonisothermal CO 2 reactivity of the cokes. The crystalline order of carbon and the concentration of alkalis were found to increase as the coke descended through thermal reserve zone to the cohesive zone of the EBF. The crystallite height (L c ) of EBF coke carbon displayed a linear correlation with the measured EBF temperatures demonstrating the strong effect of temperature on carbon structure of coke in the EBF. Alkali concentration of the coke was increased as it descended into the EBF, and was uniformly distributed throughout the coke matrix. The CO 2 reactivity of lower zone cokes was found to increase when compared to the reactivity of the upper zones cokes, and was related to the catalytic effect of increased alkalis concentration. The deterioration of coke quality particularly coke strength and abrasion propensity were related to coke graphitisation, alkalization and reactivity. Coke graphitisation is shown to have a strong influence on the coke degradation behaviour in the EBF.KEY WORDS: coke; CSR; abrasion; graphitisation, XRD; gasification; TGA reactivity; alkali.experimental blast furnace. Even though the EBF tests are time consuming, tedious and highly expensive, the information generated is of great value in terms of their reliability suitability due to simulation of more realistic conditions of a blast furnace process.Coke degradation in a blast furnace occurs due to chemical, mechanical and thermal effects. At higher flame temperature, cracking of coke is mainly attributed to thermal stress while at lower temperatures, the degradation behaviour is influenced by coke reactivity which is dependent on other coke properties. The coke reactivity can be influenced by its three major properties namely porosity, carbon structure and constituent minerals. Coke pore structure is modified by growth and/or coalescence of pores, which is often related to fluidity and swelling characteristics of parent coals, 5) and modifies the available carbon surface area for gas reactions. Coke displays graphitisation behaviour particularly at temperatures exceeding 1 200°C, which is influenced by the catalytic effect of minerals such as iron, and is believed to weaken the abrasion resistance.6) Iron in coke is also believed to catalyze gasification reactions 7) which could have different implications on coke behavior in the EBF. The influence of other minerals particularly those containing alkali on the coke degradation is less certain. The main aim of this study is to investigate the effect of alkalis on coke behaviour in the experimental blast furnace. Therefore, it is imperative to discuss further various aspects of alkalis influence on...

SUMMARYThe iron and steel industry is a large energy user in the manufacturing sector. Carbon dioxide from the steel industry accounts for about 5-7% of the total anthropogenic CO 2 emission. Concerns about energy consumption and climate change have been growing on the sustainability agenda of the steel industry. The CO 2 emission will be heavily influenced with increasing steel production in the world. It is of great interest to evaluate and decrease the specific CO 2 emission and to find out feasible solutions for its reduction. In this work, a process integration method focusing on the integrated steel plant system has been applied. In this paper, an optimization model, which can be used to evaluate CO 2 emission for the integrated steel plant system, is presented. Two application cases of analysing CO 2 emission reduction possibilities are included in the paper. Furthermore, the possibility to apply the model for a specific integrated steel plant has been discussed. The research work on the optimization of energy and CO 2 emission has shown that it is possible to create a combined optimization tool that is powerful to assess the system performance from several aspects for the steel plant.

The role of ferrous raw materials and iron ore agglomeration in energy consumption of integrated steelmaking has been evaluated using a system-wide model. Four steelplant cases were defined: typical European steelplant with sinterplant; Nordic steelplant with sinterplant; European steelplant with sinter:pellet ratio of 50%, and Nordic steelplant charging pellets and a small amount of briquettes. Energy consumption in the mining system were estimated from published statistics at 150 MJ/t for lump ore and sinter fines, 650 MJ/t for pellets made from magnetite and 1 050 MJ/t for pellets made from hematite. An integrated steelplant model including all major unit operations was used to calculate overall system energy consumption from iron ore mining to hot rolled coil. Adjustments were made accounting for energy benefit of ground granulated blast furnace slag in cement production, energy required for cement production required for briquetting, and excess BF and BOF gas producing electricity in a 32% efficient power plant. The system-wide net adjusted energy in the first three steeplant cases showed marginal improvement with use of high grade sinter fines and decrease of pellet/sinter ratio to 50% compared to typical European case. Nordic steelplant charging pellets and briquettes had a reduction in system-wide energy of 5% to 8% for charging pellets from hematite or magnetite respectively compared to the typical European steelplant charging sinter and pellets made from hematite ore. Replacement of sinter with pellets was mainly responsible for the improvement with smaller contributions from magnetite ore in pelletizing.