W. Bialik

Importance of Electrodes Slipping Algorithm for the Ferrosilicon Smelting Process

The electric arc is one of the most unstable parts of the electrical circuit of submerged-arc furnaces in the ferrosilicon smelting process. In the carbothermal silica reduction electric arc has an important role as a high temperature heat source, and its presence is essential for the proper ferrosilicon process flow. Presence of the of electric arc and temperature conditions of the ferrosilicon process have a direct relationship with position of the electrodes tip and electrodes slipping. In the ferroalloy industry position of electrodes tip as similar as metallurgical parameters of the process are not directly measured. Most often these assessments are still based to a large extent on intuition and experience operating staff of the furnaces, and have qualitative and subjective character. In order to check the existing algorithm of electrodes slipping was carried out statistical studies of the FeSi75 ferrosilicon smelting process. The study was conducted at discrete intervals ∆t = 8h using data recorded by the furnace computer measuring system and methods of statistical data processing. It was found that the size of the electrodes slipping, and Cfix ratio in the feed are correlated and are among the most important parameters which have an impact on the technical and economic indicators of the process.

Modelling of Nitric Oxide Formation During Liquid Fuel Combustion

A liquid fuel combustion process, being a source of many environmentally hazardous pollutants (e.g. nitric oxides, carbon monoxide, polycyclic aromatic hydrocarbons, soot and sulphur oxides), is a subject of extensive research aimed at reduction of their emissions. A high temperature of the combustion air tends to increase the content of NOX in exhaust gases. Based on the experimental data and literature as well as using the CFD tools, a model of light fuel oil combustion has been developed with an emphasis on nitric oxide formation. The model adequately reflects the impact of geometry changes in the flow of combustion substrates on concentrations of carbon monoxide and nitric oxides in the chamber. The quantitative results obtained are comparable to the experimental data.

Analysis of the Possibilities Using of the Post-Reaction Gases Enthalpy from the Ferrosilicon Smelting Process

The paper presents an analysis of the possibilities of using the enthalpy of post-reaction gases from the ferrosilicon smelting process to produce electricity. Ferrosilicon smelting in the submerged arc furnace is one of the most energy-consuming electro thermal processes. Post-reaction gases, generated during the silica reduction process with carbon, contain significant amounts of energy. In the past the issue of energy recovery from the ferrosilicon process has been repeatedly taken, but for the Polish ferroalloy industry it is still valid. In order to determine the amount of energy possible for recovery calculations based on mass and energy balances has been carried out and determined the stream enthalpy of post processing gas. For preparing the balance sheets has been used operational data from the 20 MVA furnace and the overall reaction of the silica reduction process. It was assumed that the reduction process occurs at a temperature of 1650°C, and the temperature of leaving post-reaction gas, whose main ingredients are oxides CO and SiO, is 750°C.

Effects of Raw Material Contaminants on the Ferrosilicon Melting Process in the Submerged Arc Furnace

Based on the Minimum Gibbs Free Enthalpy algorithm (FEM) and a model of reaction zones located around electrode tips in the submerged arc furnace, an analysis of the raw material chemical composition influence on the ferrosilicon smelting process was carried out. A model of the ferrosilicon process in the submerged arc furnace is a system of two closed isothermal reactors: an upper one with a lower temperature T1, and a lower one with a higher temperature T2. Between the reactors and the environment as well as between the reactors inside the system, a periodical exchange of mass occurs at the moments when the equilibrium state is reached. Based on the model, sets of calculations were performed: for a Fe-Si-O-C system and, subsequently, for a more complex Fe-Si-O-C-Al-Ca-Mg-Ti system. For both systems, the energy and mass balance values were calculated and the effects of raw material contaminants on the efficiency of the ferrosilicon melting process were determined.