IRON AND STEEL: PRINCIPLES, TECHNOLOGIES AND INDUSTRIAL PRACTICE

The slab surface quality is influenced by the mold level stability. Serious mold level fluctuation makes additional production cost for the derived slab machine scarfing process. Different types of mold level fluctuation in a continuous casting process can be observed online through the application of a real time fast Fourier transform method. Four types of compensators which are phase-lead, phase-lag, sliding mode and periodic mode applied to the mold level control with a control logic based on the results of FFT. Each compensator corresponds to a specific type of fluctuation. From a statistic result, the phase-lead compensator is mostly triggered at the casting of the silicon steel and the periodic mode is mostly triggered at the peritectic steel casting. A low-pass filter is also adopted to ignore the standing wave effect on the flow control actuator. The advanced compensator is put into practical use at the #5 Slab CC of China Steel Corporation in 2011 and the mold level fluctuation is reduced to about 60% of conventional PID mode. The accumulated mold level fluctuation can be down from 1000 to 80 mm per minute at the peritectic steel casting.

In the steel industry, annealing furnaces are used for reheating and heat treatment of steel strips. To realize a continuous operation of the furnace, the strips are welded together to form an infinite strip. For a high product quality, the strip has to be heated according to a predetermined heating curve while passing through the furnace. From a control point of view, this is a challenging task, particularly when a welded joint traverses the furnace. The task is further complicated by the fact, that the strip temperature usually can be monitored by radiation pyrometers only, which are located at a few discrete points. For accurate model-based control for the strip temperature, a mathematical model of the furnace is required.In the presented paper, a dynamical model of a strip annealing furnace, which is designed as a tunnel furnace, is proposed. The furnace is divided into several heating zones, where the local temperatures are used as model inputs. The presented model takes into account the most important underlying physical phenomena, i.e., the energy balance of the strip and the heat transfer by radiation. For determining the radiative heat transfer, radiation balances in the form of integral equations are used. Approximate solutions of these equations are obtained by means of the method of weighted residuals. Furthermore, the strip motion is described in a Lagrangian framework, which facilitates an accurate representation of the strip temperature, which is especially useful at welded joints. The capabilities of the model are explored in simulation studies.

An automatic control of a DRI Plant has been performed in order to provide the best possible working point, to obtain the target Level 2 Process Set Points (DRI Metallization, Carburation , Productivity) in function of Iron Ore and Reducing Gas quality. - A Process Reconstruction Model provides continuous static estimations of plant measures, efficiency analyses, virtual sensor and diagnostics- An Extended Kalman Filter provides continuous robust dynamic estimations of output process measures to feed the Regulator. - A Linear Quadratic Gaussian Regulator performs, in real time, the calculation of Optimal Controls (minimum energy, maximum gas quality Level 1 Set Points), in function of Level 2 Sets.The suite has been successfully applied to a DRI EnergIRON Plant.

The object of this study is the control of the influence of minerals, nitrogen, phosphorus and potassium during cultivation of some varieties of winter barley (hordeum vulgare L.) for beer production in the climatic conditions of Kosovo. During cultivation and production a total of six barley cultivars have been analyzed such as Bingo, Zlatko, Vannesa, Esterel, Barun while Rex was used as comparative (standard). The analysis of the breeding and production are conducted in two agro climatic regions of Kosovo (in Arbnesh Research farm of the agricultural institute of Kosovo, Peja – Dukagjin Field, and Pestova – Kosovo Fields). Experiments were carried out by the method of randomized blocks in repetitions. Area of each experimental was 10 m2. Soil analyses for minerals, nitrogen, phosphorus and potassium were conducted on two fields. In order to achieve a proper control the following factors were measured: the yield (kg/ha), the weight (1000 seeds in grams), the hectoliters weight (kg), the protein content (%), the humidity (%) and the starch. The obtained results showed that there were significant statistical differences between various levels for all investigated areas compared with the standard (Rex) and between various localities. These data served for a proper control of the quality of the beer production.

This contribution is about the active damping injection procedure for high performance converter tilting drives. Irrespective of the particular steel making process (BOF, AOD) the metallurgical reactions will cause unwanted vibrations within the mechanical equipment. The oscillations are additive to the static loads and the amplitude can affect the equipment lifetime. Therefore, it is of strong interest to suppress the process vibrations as much as possible. According to the usual fixation procedure, it is not possible to transfer dissipative energy from the equipment to the environment due to the zero velocity at the clamping. A model-based MIMO control approach exploits the opportunities given by the multiple electric drives of the converter tilting system for an active damping injection method. The presented concept shows a possible upgrade for operating drives and it is based on an extension of the current control scheme. By the way, an upgrade of the controller has a very short ROI time and it can be done during a regular maintenance break without major influence to the ongoing production process.

Ironmaking blast furnace uses fossil fuel and hence produces top gas as a by-product of ironmaking which is usually composed of 22-26% CO, 16-19% CO2, 1-4% H2 and 58-60% of N2 by volume. Blast furnace gas (BFG) is commonly used for heating, which resulted not only in very low energy efficiency, but also in the increasing CO2 emission. Meanwhile, CO and H2 are important reducing agents for iron ore reduction in BFs. Therefore, it would be a most promising technology to maximize the reuse of CO and H2 in BFG by the top gas recycling (TGR) to reduce coke consumption and production costs, thus significantly reduces CO2 emissions. TGR relies on the removal of the CO2 contained in BFG so that the useful components – CO+H2 can be recycled back into the furnace and reused as reducing agents. In addition, injecting oxygen (O2) into the furnace instead of preheated air, removes unwanted nitrogen (N2) from the gas, facilitating CO2 Capture and Storage (CCS). However, there are still two issues, i. E., supply of oxygen and storage of CO2, which are difficult to overcome due to economic and technical barriers. In addition, process for CO2 capture is also needed to be further optimized. To address the issues, this study aims to develop an alternative TGR technology in order to optimize the CO2 separation from BFG and maximize utilizing carbon and hydrogen in BFs. The study will demonstrate a process to capture CO2 from BFG with calcium looping packed bed carbonators, convert it to CO and H2 using non-thermal plasma with steam addition, and then directly re-inject the production gas into blast furnace. This research involves numerical and experimental simulation that will generate important information on technical and economic feasibility applying TGR technology in ironmaking blast furnace. It deals with several novel technologies, such as calcium looping packed bed carbonators for CO2 capture and non-thermal plasma reactor for CO2 dissociation; And investigation on the effects of new TGR process on blast furnace operation. Those technologies will significantly improve carbon utilization and energy efficiency in ironmaking blast furnaces and remarkably reduce CO2 emission and ironmaking cost.