Wind heaters serve to increase the temperature of the blast from 140-200 °C to temperatures of 1030–1150 °C. Each of our blast furnaces has four wind heaters and they together consume about 40 percent of the total blast-furnace gas supply and about 10 percent of the total coking gas production. They are an organic component of the blast-furnace system. A team consisting of representatives of the departments Process and Technology Improvement and Production Transformation USSE, BSC, Blast Furnace Production and Blast Furnace Maintenance – Blast Furnace Electromaintenance shops, and of the companies Primetals England, MDJ Košice and PA Košice, identified potential savings, and developed and installed a new, more efficient system of gas combustion management in wind heaters. Taking into consideration the selection of team members, the period of the team formation and setting up creative communication within it went very fast. The group had to cope then with various pitfalls, such as different systems of heating management on each of the batteries, data transfers and limitations in hardware capacity. These days the new system controls combustion based on on-line chemical analysis of blast-furnace gas and coking gas, automatically and reliably managing residual oxygen content in the exhaust gases as well. This has been fully maintained by the BSC group of Michal Dulovič. Not only operators in blast-furnace control rooms, but also key managers of the Molten Iron Production Shop underwent training for the new system in 2014. General Managers Joseph H. Morey, Martin Varga and Ján Petko brought along significant support. The new system strives for blast-furnace gas and coking gas combustion reduction and also for increase in hot wind temperature.
Project work got started back in 2013, and it started poducing benefits from the middle of 2014. Savings have exceeded USD 5.5 million since then. The software for better heating of wind heaters at blast furnaces was evaluated in the section of Vice President BSC as the best BSC project in the first quarter of 2015, and the whole team last year obtained third place among U. S. Steel Košice projects oriented towards cost reduction.
The primary work of programming activity and data manipulation was concentrated in primary production in the BSC group of M. Dulovič, whereby additional, approximately one million American dollars of external support were saved. This turned out afterwards to be another advantage, because the BSC team, Process Improvement Department and Blast Furnaces Division were able to continue work hand in hand in 2015. Without any external support they developed and also installed a new part of the information system, evaluating on a daily basis the efficiency of energy transition from heating gases into hot wind. The group of Ivan Balla, blast furnaces electromaintenance coordinator, installed an on-line analyzer of carbon and hydrogen oxide content in blast-furnace gas in 2015 to support combustion management not only of blast furnaces 1 and 2 wind heaters, but also of the other consumers connected in the company network. It should be pointed out that at the beginning significant support was provided by the Technical Diagnostics Equipment Reliability unit managed by Peter Kuruc, but also by Peter Semanec's group in the Controlling Production Support Department.
The new management system enabled the creation of an application for on-line calculation of heat balance input/output for each wind heater battery, and began to monitor wind heater efficiency. This creative step was the basis for further system development and installation of automatic management of fuel quantity for each individual wind heater, based on blast quantity, cold wind temperature, hot wind required temperature and calorific power of heating gases.
A common challenge for 2016/2017 for the Process Improvement, BSC and Blast Furnaces Division teams is to start wind heater heating management without any direct operator intervention. This approach involves additional possibilities for heating gas consumption savings as well as potential for hot wind stability and temperature increase. These teams are going to continue in 2016 also in heat exchanger operation restoration for the heaters of blast furnace no. 1, so that combustion air temperature returns again after five years from common ambient temperature to temperature 170 – 200°C and energy is utilized for coking gas consumption saving or for increase in hot wind temperature. Intensive support and initiative are at the same time provided by the team of Blast Furnaces Maintenance operating manager Samuel Steranko.
Regarding BAT (best available techniques), the team consisting of representatives of Process Improvement, BSC, Blast Furnaces, Engineering, Environment and Production Support departments has been intensively working on a task, so that when meeting BAT demands after April 2016 we are able henceforth to fully internally recycle ferrous units from fine oil mill scale.
Last but not least, close team cooperation should be remembered within the Engineering, Process Improvement, BSC and Blast Furnaces Division group during installation of a new system of obtaining heat from waste gases for the wind heaters at blast furnace no. 3, and increasing blast-furnace gas and combustion air temperatures from ambient temperature to 150°C. This project is going to bring benefits from April 2016. In the course of gradual completion of the equipment, the team headed by František Konečný from the Engineering Department, as well as BSC groups and operators are going to be steadily increasingly active.
As can be seen from the Carnegie Way information system, the above-mentioned approach and results have attracted the molten iron production group in the affiliated Gary Works. A new project aiming to optimize combustion in blast-furnace heaters was started with the objective to increase hot wind temperature. This is a new opportunity for the Košice team for experience exchange and comparison of results attained.
RNDr. Jaroslav Čurilla, PhD.
He has been employed in U. S. Steel Košice since 1995 as a research worker in the area of blast-furnace and steel plant waste recycling and environment. In 2001 he became the first manager of the Primary Production and Ecology department within the then Research and Testing Institute. Between 2004 – 2008 he directly participated in technology and raw materials quality management in the USA in the blast furnace plants at Gary Works and Great Lakes Works. After returning from the United States he again became involved in blast-furnace process technology and raw materials management in Košice and Smederevo. Since this period, USSK has started to fully utilize all the coke produced at home in its own blast-furnace and sintering processes. As manager for blast furnaces and raw materials, since 2014 J. Čurilla has been a member of the team in the Department of Process and Technology Improvement and Production Transformation USSE. In 2010 he finished his studies at the Blast Furnace Academy of McMaster University, Hamilton, Canada. He has been regularly attending and also publishing results of work in the area of primary production at important European and worldwide congresses. He has been active in the European Commission blast furnaces team in the area of data and experience exchange, he has been communicating with the World Steel Association within the areas of LCI and recycling, he has led and participated in the work of multibranch teams engaged in cost reduction in primary production, energy consumption and distribution, waste evaluation and disposal. He has earned a Six Sigma Green Belt certificate for the area of project management and process improvement.