Material efficiency is one of the most effective methods for achieving more sustainable operations in iron and steelmaking. Sintering and briquetting processes are commonly used in integrated steel plants to recycle carbon- and iron-containing residues back to blast furnace. In the Ruukki steelworks in Finland, a surplus of solid coking plant by-products is produced, none of which are presently utilized within the steelworks. In this paper, a novel concept for recycling solid coking plant by-products to a blast furnace via liquid-solid injection is evaluated. According to the conducted laboratory study, all the solid by-products could be utilized via liquid-solid mixture injection. By pulverizing the coke gravel and coke sand and mixing it with extra heavy bottom oil, the annual coke requirement of a blast furnace could be decreased by almost 9% with constant oil injection and could reduce annual oil requirements by almost 39% with constant coke rate. Evaluation of direct and indirect environmental impacts reveals that there would be more positive than negative impacts when recycling solid coking plant by-products inside steel plant boundaries.
References
[1]
World Steel Association. Steel Statistical Yearbook 2012; World Steel Association: Brussels, Belgium, 2012.
[2]
Das, B.; Prakash, S.; Reddy, P.S.R.; Misra, V.N. An overview of utilization of slag and sludge from steel industries. Resour. Conserv. Recycl. 2007, 50, 40–57.
[3]
Shatokha, V.I.; Gogenko, O.O.; Kripak, S.M. Utilising of the oiled rolling mills scale in iron ore sintering process. Resour. Conserv. Recycl. 2011, 55, 435–440.
[4]
Singh, M.; Bj？rkman, B. Effect of processing parameters on the swelling behaviour of cement-bonded briquettes. ISIJ Int. 2004, 44, 59–68, doi:10.2355/isijinternational.44.59.
[5]
Doronin, I.E.; Svyazhin, A.G. Commercial methods of recycling dust from steelmaking. Metallurgist 2011, 54, 673–681, doi:10.1007/s11015-011-9356-z.
[6]
Remus, R.; Aguado Monsonet, M.A.; Roudier, S.; Sancho, L.D. Best Available Techniques (BAT) Reference Document for Iron and Steel Production: Industrial Emissions Directive 2010/75/EU (Integrated Pollution Prevention and Control); Publications Office of the European Union: Luxembourg, 2013.
[7]
Yabe, S.; Iba, T.; Miyazaki, T.; Satoh, K.; Kojima, M.; Aminaga, Y. COM and CTM injection into all tuyeres of Kashima No.3 blast furnace. Ironmak. Proc. Metall. Soc. AIME 1983, 42, 541–547.
[8]
Makkonen, H.T.; Heino, J.; Laitila, L.; Hiltunen, A.; P？yli？, E.; H？rkki, J. Optimisation of steel plant recycling in Finland: Dusts, scales and sludge. Resour. Conserv. Recycl. 2002, 35, 77–84, doi:10.1016/S0921-3449(01)00123-9.
[9]
Diemer, P.; Killich, H.J.; Knop, K.; Lüngen, H.B.; Reinke, M.; Schm？le, P. Potentials for utilization of coke oven gas in integrated iron and steel works. In Second International Meeting on Ironmaking; First International Symposium on Iron Ore: Espírito Santo, Brazil, 2004.
[10]
Babich, A.; Senk, D.; Fernandez, M. Charcoal behavior by its injection into the modern blast furnace. ISIJ Int. 2010, 50, 81–88, doi:10.2355/isijinternational.50.81.
[11]
Andahazy, D.; Slaby, S.; L？ffler, G.; Winter, F.; Feilmayr, C.; Bürgler, T. Governing processes of gas and oil injection into the blast furnace. ISIJ Int. 2006, 46, 496–502.
[12]
Parikh, J.; Channiwala, S.A.; Ghosal, G.K. A correlation for calculating HHV from proximate analysis of solid fuels. Fuel. 2005, 84, 487–494, doi:10.1016/j.fuel.2004.10.010.
[13]
Geerdes, M.; Toxopeus, H.; van der Vliet, C. Modern Blast Furnace Ironmaking—An Introduction, 2nd ed.; IOS Press: Amsterdam, The Netherlands, 2009; pp. 47–57.
[14]
Ariyama, T.; Murai, R.; Ishii, J.; Sato, M. Reduction of CO2 emissions from integrated steel works and its subjects for a future study. ISIJ Int. 2005, 45, 1371–1378, doi:10.2355/isijinternational.45.1371.
[15]
Ruukki Web Page. Environmental Data Monitor. Available online: http://www.ruukki.com/Corporate-responsibility/Environment/Environmental-data-monitor (accessed on 5 January 2013).
[16]
Kinnunen, K.; Paananen, T.; Lilja, J. Modelling and simulation of Blast Furnace Process for switch from Sinter to Pellet Operation. In Proceedings of 4th International Conference on Modelling and Simulation of Metallurgical Processes in Steelmaking, Düsseldorf, Germany, 27 June–1 July 2011.
[17]
Salo, A. The Viscosity Measurements of Blast Furnace Injectants [in Finnish]. Master’s Thesis, University of Oulu, Oulu, Finland, 5 April 2012.
[18]
Mertdogan, A.; Marlin, L.A.; Beaucair, V.D.; Jansto, S.G. Production and use of coal-oil mixture as blast furnace auxiliary fuel. Ironmak. Proc. Metall. Soc. AIME 1983, 42, 593–606.
[19]
It is assumed that all the carbon entering to blast furnace is transformed into CO2. In practice hot metal has C-content of 4.5%, which is decreased close to zero in basic oxygen furnace. Carbon content of coke, oil, coal tar and coke fines are assumed to be 88%, 87%, 88% and 87% respectively.
[20]
Esteban, L.S.; Carrasco, J.E. Evaluation of different strategies for pulverization of forest biomasses. Powder Technol. 2006, 166, 139–151, doi:10.1016/j.powtec.2006.05.018.
[21]
The average Finnish emission factor for electricity is 210 kg/MWh.
[22]
Ditsele, O.; Awuah-Offei, K. Effect of mine characteristics on life cycle impacts of US surface coal mining. Int. J. Life Cycle Assess. 2012, 17, 287–294, doi:10.1007/s11367-011-0354-y.
[23]
Mangena, S.J.; Brent, A.C. Application of a Life Cycle Impact Assessment framework to evaluate and compare environmental performances with economic values of supplied coal products. J. Clean. Prod. 2006, 14, 1071–1084, doi:10.1016/j.jclepro.2004.04.012.
[24]
Wikstr？m, J.O.; Grip, G.E.; Larsson, M.; ？ngstr？m, S. Ways to Reduce CO2 Emissions at SSAB Lule？ Works. In Proceedings of 2nd International Conference on New Developments in Metallurgical Process Technology, Riva del Garda, Italy, 19–21 September 2004.
[25]
Sepp？l？, J.; Koskela, S.; Melanen, M.; Palperi, M. The Finnish metals industry and the environment. Resour. Conserv. Recycl. 2002, 35, 61–76, doi:10.1016/S0921-3449(01)00122-7.
