Non Coking Coal for Iron Production...

Non Coking Coal for Iron Production A non-coking coal is that coal which when heated in the absence of air leaves a coherent residue. This residue does not possess the physical and chemical properties of the coke and is not suitable for the manufacture of coke. Non coking coal like any other coal is an organic rock (as opposed to most other rocks in the earth’s crust, such as clays and sandstone, which are inorganic). It contains mostly carbon (C), but it also has hydrogen (H2), oxygen (O2), sulphur (S) and nitrogen (N2), as well as some inorganic constituents which are known as ash (minerals) and water (H2O). Coal was formed from prehistoric plants, in marshy environments, some tens or hundreds of millions of years ago. The presence of water restricted the supply of oxygen and allowed thermal and bacterial decomposition of plant material to take place, instead of the completion of the carbon cycle. Under these conditions of anaerobic decay, in the so-called biochemical stage of coal formation, a carbon-rich material called ‘peat’ was formed. In the subsequent geochemical stage, the different time-temperature histories led to the formations of coal of widely differing properties. These formations of coal are lignite (65 % to 72 % carbon), sub-bituminous coal (72 % to 76 % carbon), bituminous coal (76 % to 90 % carbon), and anthracite (90 % to 95 %) carbon. The degree of change undergone by a coal as it matures from peat to anthracite is known as coalification. Coalification has an important bearing on the physical and chemical properties of coal and is referred to as the ‘rank’ of the coal. Ranking is determined by the degree of transformation of the original plant material to carbon. The ranks of coals, from those with...

Selection of Coal for inclusion in Coal Blend in Coke Making Sep26

Selection of Coal for inclusion in Coal Blend in Coke Making...

Selection of Coal for inclusion in Coal Blend in Coke Making Blending of coals is necessary from economical point of view by reducing the percentage of high cost, prime or hard coking coals and replacing it with medium or soft coking coals. In some coke oven plants even a small percentage of non-coking or steam coals have also been used in the blend. Selection of a proper coal blend for use in by product coke ovens is always a big challenge for the coke producer since the blend has to meet the following requirements. It is to meet the requirement of crushing during coal preparation. All the components of the coals are neither be over crushed or under crushed. The sized coal blend for charging the coke ovens is to meet the requirements of density, flow, and the size fractions. It is to have necessary coking and caking properties for producing coke of quality which meets the quality requirements of blast furnace (BF) coke. The three basic quality requirements of BF coke are (i) to provide heat for the endothermic reactions taking place in the blast furnace, (ii) to act as a reducing agent by producing the necessary reduction gases, and (iii) to provide a permeable support in the BF for the iron bearing burden. It is to provide safe pushing performance in coke ovens. It must not put excessive pressure on coke oven walls during the process of coking and damage them. It should meet the yield requirements not only of BF coke but also of coke oven gas. A proper coal blend will not produce excessive nut coke and coke breeze. It is to be economical. In view of the above varied types of requirements, the decisions regarding coal blends are not...

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...

Understanding Coke Making in Byproduct Coke Oven Battery Mar09

Understanding Coke Making in Byproduct Coke Oven Battery...

Understanding Coke Making in Byproduct Coke Oven Battery  Coke is one of the basic materials used in blast furnaces for the conversion of iron ore into hot metal (liquid iron), most of which is subsequently processed into steel. The major portion of coke produced is used for the production of hot metal. Coke is also used by a number of other industries, namely iron foundries, nonferrous smelters, and chemical plants. It is also used in steel making as a carburizing material. Coke and coke by-products, including coke oven gas, are produced by the pyrolysis (heating in the absence of air) of suitable grades of coal. The process also includes the processing of coke oven gas to remove tar,  ammonia (usually recovered as ammonium sulphate), phenol, naphthalene, light oil, and sulphl, and sulfs under links n of coal)  period.e doorg nitrogen gas is used for the production of steam and then power.ur before the gas is used as fuel for heating the ovens. The coke making industry consists of two sectors, integrated plants and merchant plants. Integrated plants are owned by or affiliated with iron-and steel producing plants who produce blast furnace coke primarily for consumption in their own blast furnaces. Independent merchant plants produce furnace and/or foundry coke for sale in the open market. These plants sell most of their products to other plants engaged in blast furnace, foundry, and nonferrous smelting operations. A good quality coke is generally made from carbonization of good quality coking coal. Coking coals are defined as those coals that on carbonization pass through softening, swelling, and re-solidification to coke. One important consideration in selecting a coal blend is that it should not exert a high coke oven wall pressure and should contract sufficiently to allow the coke to...

Energy Efficiency and Iron and Steel Production Sep09

Energy Efficiency and Iron and Steel Production...

Energy Efficiency and Iron and Steel Production  In the recent years, the need for a more rational and efficient use of energy has emerged as a strategic and urgent issue. Such a necessity is particularly perceived in the iron and steel production, not only because of the increasing costs of energy, but also as a consequence of the competition, which stresses some features of the process and its final products (e.g. cost and quality). Also, the rational use of the energy resource may be 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 born to procure energy. Globally, ever increasing consumption of energy has gone hand in hand with rising concerns about its conservation. Apart from being expensive and prone to sudden price fluctuations, the overwhelming majority of energy sources are non renewable. Therefore, the conservation of energy is considered vital not just to avoid wastage of a precious resource, but also to slow down the rapid depletion of coal, oil, and natural gas resources. However, with the environmental movement gaining ground in the past 30 years, the ramifications of unsustainable energy use are no longer confined to economics alone. As the bulk of greenhouse gas (GHG) emissions are a result of fossil fuel burning, conservation of energy is today intrinsically linked to the climate question. As halting fossil fuel use is not an option without the viability of alternative sources, the only way to reduce energy use and manage emissions is therefore to maximize its efficiency. Since the iron and steel industry presents one of the most energy intensive sectors within the economy of any country,...