Industrial Heating Furnaces and their Types...

Industrial Heating Furnaces and their Types A furnace is equipment which is used as a reactor, or for melting of metals for casting, or to heat materials to change their shape (e.g. rolling, forging etc.) or properties (heat treatment). Industrial furnaces are mainly used for carrying out the process or for the purpose of heating. Furnaces which are used for carrying out the processes are sometimes known as reactors. Industrial furnaces which do not ‘show colour’, that is, in which the temperature is below 650 deg C are sometimes called ‘ovens’. However, the dividing line between ovens and furnaces is not very sharp. As an example, coke ovens operate at temperatures above 1400 deg C. In the ceramic industry, furnaces are called ‘kilns’. In the petrochemical and chemical process industries, furnaces are termed ‘heaters’, ‘kilns’, ‘afterburners’, ‘incinerators’, or ‘destructors’. The furnace of a boiler is known as its ‘firebox’ or ‘combustion chamber. Industrial heating furnaces are insulated enclosures designed to deliver heat to loads for many forms of heat processing. Furnaces used as reactors, and melting furnaces require very high temperatures and can involve erosive and corrosive conditions. Shaping operations need high temperatures to soften materials for processes such as forging, swaging, rolling, pressing, bending, and extruding etc. Heat treating operations need midrange temperatures to physically change crystalline structures or chemically (metallurgically) alter surface compounds, including hardening or relieving strains in metals, or modifying their ductility. These include aging, annealing, normalizing, tempering, austenitizing, carburizing, hardening, malleabilizing, nitriding, sintering, spheroidizing, and stress relieving etc. Industrial processes which use low temperatures include drying, coating, polymerizing, and chemical changes etc. Industrial heating operations encompass a wide range of temperatures, which depend partly on the material being heated and partly on the purpose of the heating process and...

Compressed Air System in a Steel Plant...

Compressed Air System in a Steel Plant Compressed air is the air which is kept under a pressure having a value greater than the atmospheric pressure (1.03 kg/sq cm). It is a medium that carries potential energy. Compressed air is a widely used utility in a steel plant. It is an important source of instrument air. Other than instrumentation air which is completely dry and free from contaminants, there are the following three main uses of compressed air in a steel plant. Blast air for blast furnace For the production of oxygen, nitrogen and argon in an air separation plant A utility gas with many uses. Major among it is the operation of pneumatic devices Normally for blast furnace the cold blast air is supplied either by a turbo-blower or an electric blower. In the air separation plant, there are dedicated compressors producing compressed air of the specification needed by the air separation plant for the production of oxygen, nitrogen and argon gases. In case of compressed air being used as a utility gas, steel plants usually have either a centralized compressed air system or/and local compressed air systems. Compressed air is an expensive utility when evaluated on a per unit energy delivered basis. The advantage with the use of compressed air is that it can be easily stored in air receivers and readily available for brief peak demand periods. There are inefficiencies in converting electricity into compressed air as well as line losses in the compressed air distribution. Although the total energy consumption of such systems is normally small, compressed air systems are the most expensive energy in the steel plant due to its very low efficiency. Typical energy efficiency of a compressed air system is around 12 % to 15 %.  Various measures can help...

Energy Conservation in a Steel Plant...

Energy Conservation in a Steel Plant Production of iron and steel is an energy intensive manufacturing process and needs natural resources (including the energy resource) in large amounts. Energy cost is one of the major costs in the operation of the steel plant. The energy efficiency and hence the energy consumption of the steel plant varies depending on production route, type of iron ore and coal used, the steel product mix, operation control technologies employed, and material efficiency of the plant. Conservation of energy is one of the most effective ways to improve the energy efficiency, to reduce the energy consumption, and to lower the costs with an added benefit of reducing the impact of the steel plant on the environment. In recent years, the need for a more rational and efficient use of energy has emerged as a strategic and urgent issue. The rational use of the energy resource is being regarded as a twofold issue, a first aspect being related to the achieved consciousness of the limited availability of energy, regarded as a source, and the second being represented by a mature appreciation of the costs incurred to procure energy. The cost of energy is not only the important motivation for the steel plant management to make efforts towards energy conservation and to increase the energy efficiency of the processes but the threat of energy shortages is leading the management to take steps for the conservation of the energy. Energy conservation also helps the steel plant towards its societal goal towards reduction of the generation of greenhouse gases. The composition and local conditions of each steel plant is different, and based on each unique situation the most favourable selection of energy conservation opportunities are required to be made to address to the...

Energy Audit in an Integrated Iron and Steel Plant...

Energy Audit in an Integrated Iron and Steel Plant Energy audit is a key requirement for an integrated iron and steel plant which helps it to identify and realize energy efficiency improvements in a systematic way. It assists the steel plant management in understanding how it uses energy and helps to identify the areas where waste occurs and where opportunities for improvement exist. Energy audit is the inspection, examination, analysis and evaluation of the physical and financial processes of the steel plant relating to the use of the energy. The aim of the energy audit is to systematically identify the potential for saving energy and make recommendations for improvement. Energy audit is the key to a systematic approach for decision making in the area of energy management.It attempts to balance the total energy inputs with its use, and serves to identify all the energy streams in the steel plant. It quantifies energy usage according to its discrete functions. It is an effective tool in defining and pursuing comprehensive management of the energy usage in various processes of the steel plant. Energy audit helps to understand more about the ways energies and fuels are used in various processes of the steel plant. It helps in identifying the areas where waste of energy is occurring and where scope for improvement in energy consumption exists. It gives a positive orientation to the energy cost reduction and helps to keep focus on variations which occur in the availability and reliability of supply of energies and their costs, decide on appropriate energy mix, identify energy conservation technologies, retrofit for energy conservation equipment etc. It is the translation of conservation ideas into realities, by identifying technically feasible solutions with economic and other organizational considerations within a specified time frame. Energy...

Types of Energy used in a Steel Plants and Energy Conservation...

Types of Energy used in a Steel Plants and Energy Conservation Energy is needed to do any work. Energy can be in the form of potential energy or it can be in the form kinetic energy. Potential energy is stored energy and for doing the work it is to be released from the storage.  Common example of potential energy are fuel energy, chemical energy and  pressure energy etc. Kinetic energy is energy due to motion and example of kinetic energy is electric energy which is the movement of electrons. Energy conservation activities are the efforts made towards reduction in energy consumption for doing a work. These efforts can be in the form of reduction of energy wastages, recovery and recycling of waste energy, and/or by improving the energy efficiency of the processes. Various forms of energy used in an integrated steel plant are described below.  Fuel energy Fuel energy is the potential energy which constitutes the major component of all the form of energies used in the steel plant. Fuel energy is used in the form of primary fuels and the byproduct fuels. Primary fuels used in steel plant are (i) solid fuels, (ii) liquid fuels, and (iii) gaseous fuels. Byproduct fuels are mainly coke oven gas recovered during coking process of metallurgical coals, blast furnace gas recovered from blast furnace during the production of hot metal, converter gas recovered during the production of steel in the basic oxygen furnace process, and coal tar fuel produced during the cleaning of the raw coke oven gas produced while coking of the metallurgical coals. Solid fuels used in the steel plant are coal and/or coke. Solid fuels constitute the highest percentage of energy consumed in steel plant. Both metallurgical (coking) coals and non coking coals are...