Technologies for Improving Blast Furnace Operating Performance Oct03

Technologies for Improving Blast Furnace Operating Performance...

Technologies for Improving Blast Furnace Operating Performance A blast furnace (BF) is an investment in the future. Hence it is necessary that there is the proper dimensioning of all equipment, systems and components as well as incorporation of technologies which assure the desired production and quality so that improved performance of the blast furnace can be achieved. This is particularly true when blast furnace goes for capital repairs. During capital repairs incorporation of technologies for the improvement of blast furnace operating performance also meet the new demands placed on the performance of the blast furnace, personnel safety, lower maintenance requirements and environmental compliance. A key challenge for blast furnace operators has always been to assure a continuous and reliable supply of hot metal for the steel melting shop at uniform quality and at the lowest possible costs. Any interruption in the production of hot metal can lead to potential standstills in the downstream production and processing facilities. Downtime must be kept to a minimum while the blast furnace campaign life must be extended for as long as possible. Fluctuations in blast furnace operating parameters must be avoided for uniform hot metal quality, which is only possible through the application of proper technologies as well as sophisticated automation and process control solutions. There are several technologies (Fig 1), which when adopted greatly improve blast furnace operating performance and increase its efficiency both with respect to productivity and fuel consumption. This results into improved hot metal production rate per unit of volume of blast furnace and reduced consumption of BF coke. Some of the major technologies are described below. Fig 1 Technologies for improving BF operating performance Increase in furnace internal volume By using advanced technologies for furnace refractory lining and furnace cooling, it is possible...

Oxygen gas and its usage in Steel Plant...

Oxygen gas and its usage in Steel Plant Oxygen is an active, life sustaining component of the atmosphere. The percentage of oxygen in air is 20.94 % by volume or 23 % by weight of the air. It is the most widely occurring element on the mother earth.  Because it forms compounds with virtually all chemical elements except the noble gases, most terrestrial oxygen is bound with other elements in compounds such as silicates, oxides, and water. Oxygen is also dissolved in rivers, lakes, and oceans.  Molecular oxygen occurs almost entirely in the atmosphere. Between 1770 and 1780, Swedish pharmacist Carl Wilhelm Scheele, British clergyman Joseph Priestley and French chemist Antoine Laurent Lavoisier researched, documented and helped discover oxygen. The name oxygen was first used by Lavoisier in 1777. It was only later that its high level of chemical reactivity was discovered. Oxygen is produced in large quantities and at high purity as a gas or liquid through the liquefaction and distillation of ambient air at the cryogenic air separation plants. It is also produced on commercial scales as a lower purity gas (typically about 93 %) by adsorption technologies (pressure swing adsorption (PSA), or vacuum-pressure swing adsorption (VPSA or VSA). Very pure oxygen can be produced by the electrolysis of water. Gaseous oxygen is called in short as GOX while the liquid oxygen is called in short as LOX. Liquid oxygen is a cryogenic liquid. Cryogenic liquids are liquefied gases that have a normal boiling point below – 150 deg C. Liquid oxygen has a boiling point of -183 deg C. Because the temperature difference between the product and the surrounding environment is substantial, it is necessary to keep the liquid oxygen insulated from the surrounding heat. Oxygen also requires special equipment for handling and storage....

Industrial gases used in steel industry...

Industrial gases used in steel industry The term “Industrial gas” refers to a group of gases (Fig 1) which are specifically produced for use in a variety of industrial processes. They are distinct from the fuel gases. Speciality gases such as neon, krypton, xenon and helium are sometimes considered under the category of industrial gases.  Industrial gases are produced and supplied in both gas and liquid form and transported in cylinder, as bulk liquid or in pipelines as gas. Industrial gases usually used in steel industry are oxygen, nitrogen, argon and hydrogen. Fig 1 Industrial gases Oxygen Oxygen (O2) is an active component of the atmosphere making up 20.94 % by volume or 23 % by weight of the air. It is colorless, odorless and tasteless. Oxygen is highly oxidizing.  Oxygen reacts vigorously with combustible materials, especially in its pure state, releasing heat in the reaction process. Many reactions require the presence of water or are accelerated by a catalyst. Oxygen has a low boiling/ condensing point which is -183 deg C. The gas is approximately 1.1 times heavier than air and is slightly soluble in water and alcohol.  Below its boiling point, oxygen is a pale blue liquid slightly heavier than water. Properties of oxygen are at Tab 1. Oxygen is produced in large quantities and at high purity as a gas or liquid by cryogenic distillation and in smaller quantities as a lower purity gas (typically about 93%) by adsorption technologies such as pressure swing adsorption (PSA) or vacuum pressure swing adsorption (VPSA or VSA). Oxygen is the second largest consumed industrial gas.  Aside from its chemical name O2 oxygen is also referred to as GOX or GO when produced and delivered in gaseous form, or as LOX or LO when in its cryogenic liquid form. Oxygen is...

HIsmelt process of Ironmaking Jul02

HIsmelt process of Ironmaking...

HIsmelt process of Ironmaking  HIsmelt is short for high intensity smelting. It is a direct smelting process for making liquid iron straight from the iron ore.  The process has been developed to treat iron ore fines with minimum pretreatment, making the process more flexible in terms of the quality of iron ore it can treat.  The process allows the use of non coking coal and iron ore fines with significant impurities. The core of the HIsmelt process is the smelt reduction vessel (SRV) which has a refractory lined hearth and water cooled upper shell. The process is carried out in this vessel. The refractory hearth contains the molten iron bath and liquid slag. The main product of the process is liquid iron or hot metal which can be used in steel melting shop or cast in pig casting machine to produce pig iron. The byproduct of the process is slag and the off gas. Main features of the process HIsmelt process has the following unique features. The method of solid injections using high speed lances ensure that the capture efficiency in the melt is high and even ultra fines can be used directly. The ‘natural’ 5 % to 6 % FeO level in the slag in conjunction with the metal carbon at 4 % creates conditions for strong partition of phosphorus from metal to slag. Typically around 80 % to 90 % of phosphorus goes to slag. Coal performance has virtually no dependence on particle morphology, since the coal is ground fine for injection. Historical process development  The origin of the HIsmelt process is traced back to the bottom blown oxygen converter process (OBM) and the evolution of the combined blowing steel making process developed by Klöckner Werke at their Maxhütte steel works.  CRA (now Rio...