Coal is used as a reducent for sponge iron making in the furnace. Schematic of optimised rotary kiln sponge iron making process. The sponge iron is processed further for making liquid metal at steel melting shop. In this pilot plant, a totally indigenous technology for production of sponge iron has been developed in which noncoking coal is essentially used as the reductant. The rotary kiln process is a commonly practiced method in india for producing coal based sponge iron. The grate kiln process which is part of the pelletizing and of great importance for this work, is further described in chapter 2. Cement production process is extremely timeconsuming 1 and the rotary kiln is the most important part of the.
Present economics of direct reduction challenges the blast furnace route to steel. Direct reduction processes with special emphasis on the melting of sponge iron. Simulation of rotary kiln used in sponge iron process. Criteria on the adaptation of the technology to the country a. Clinker from rotary or vertical shaft kiln page 1 of 1. The reduction is carried out in a rotary kiln of a predetermined temperature and controlled atmospheric pressure.
We then illustrate the approach using the cement and the iron and steel industries. Pdf a rotary kiln is a cylinder which rotates around its cylindrical axis and acts as a device to exchange the heat. Modelling and optimization of a rotary kiln direct reduction process 55 figure 3. During this stage the mixture is passed through a kiln and possibly a preheater. Rotary kiln the hot gases may be generated in an external furnace or by a flame inside the kiln. Rotary kilns sometimes called calciners or rotary furnaces are used for thermal treatment processes such as calcination, sintering, pyrolysis and firing, as well as for oxidation and reduction.
Pdf operation of coalbased sponge iron rotary kiln to reduce. The coal reacts with air to form carbon monoxide which then reduces iron oxide ore to iron. The book comprehensively explains the process of selection and testing of raw materials. One of the major challenges for sponge iron plant is the accretion formation. Heres a little bit about what a rotary kiln is and the seals we make for them. Pdf the present paper deals with 2d cfd model of sponge iron rotary kilns. A rotary kiln consists of a cylindrical, rotating body mounted between stationary material feed and outlet housings. Recovery and utilization of waste heat in a coal based.
In the sponge iron process concentrated and finely divided iron ore is reduced in solid phase into sponge iron at high temperatures in rotary kiln. The cold model study was conducted with iron ore as the feed material to determine the influence of length to diameter ratio ld of a rotary kiln on the filling degree, holdup, and residence time of the charge. World steel production with dismbution of pig ironscrapdri. Operation of coalbased sponge iron rotary kiln to reduce accretion formation and optimize quality and power generation. Consequently, they were replaced by the high production rate indirect process, and the development of modern dr process did not begin until the middle of 19th century. The reduction of iron ores, scientific basis and technology. Recovery and utilization of waste heat in a coal based sponge iron process.
A wet process kiln may be up to 200m long and 6m in diameter. An empirical equation correlating different operating variables has been derived on the basis of. In the sponge iron industry rotary kiln is the primary equip. Simulation of rotary kiln used in sponge iron process using ann iacsit international journal of engineering and technology, vol. However, rotary kiln process suffers from serious limitations like low productivity and pollution. The feed is introduced together with reducing and desulphurizing agents limestone or raw dolomite into an inclined rotary kiln, heated counter current to the flow of hot gas and reduced to form sponge. The production capacities of these industries depend significantly on the. The mean particle size of iron ore shall be restricted to 11mm in order to achieve uniform fe metallic of all grain size fraction of the product. Our cement rotary kiln and sponge iron rotary kiln has been developed for performing drying, calcination and sintering work in a continuous process. Dolomite all at 30 c rotary cooler sponge iron magnetic at 110 oc water.
Pdf the present paper deals with 2d cfd model of rotary kilns employed in sponge iron process. The feed is introduced together with reducing and desulphurizing agents limestone or raw dolomite into an inclined rotary kiln, heated counter current to the flow of hot gas and reduced to form sponge iron. The literature discussed above is based on cfd analysis of rotary kiln of cement plant. Best tmt bar manufacturing plants india in the direct reduced iron dri plant, production of sponge iron using a solid reductant involves reducing iron ore lumpspellets with a carbonaceous material such as coal.
In their basic form they were relatively simple compared with modern developments. Nov 05, 2016 rotary kiln is a pyroprocessing equipment used to raise materials to a high temperature calcinationin a continuous process, chaeng has 3005000 td cement rotray kiln, 150 td lime rotary kiln. It has to be long because a lot of water has to be evaporated. The main function of making sponge iron in the kiln is to convert iron ore into sponge iron by using iron ore, coal and dolomite limestone. Processes that produce iron by reduction of iron ore in solid state below the melting point are generally classified as dr processes. Haematite and noncoking coal are fed to the kiln at controlled rates without premixing and. Jul 06, 2012 gulin supply mining and construction equipment for mineral handling. Ibutec the rotary kiln experts for trials and production. Energy audit methodology of sponge iron manufacturing. Rotary kiln body, with drive gear and 2 tyres riding rings a rotary kiln is a pyroprocessing device used to raise materials to a high temperature calcination in a continuous process. Esp dust wet scraper waste gas dusty gas chimney steam water. Pdf production of sponge iron through tunnel kiln process. Ron mcdowall, auckland new zealan d for secretariat of the basel convention part i.
Simulation of rotary kiln used in sponge iron process using. In order to identify the largest losses and to find ways to increase the efficiency, an energy survey of the sponge iron plant was carried out for a number of. The maximum recommended kiln shell temperature varies by plant, by country and by kiln manufacturer, despite the fact that most kiln shells are made of low alloy carbon steel. Introduction in todays world, powering along the supply of raw materials, cement production is the most important factor. Operation and construction details a schematic diagram of the rotary kiln of sponge iron process considered for the present work is shown in fig. Details of rotary kiln pdf file process detail henan fumine. Power plant, chlor alkali, cement, pulp and paper and iron and steel. In rotary kiln, carbon is charged from either end, in one end in the form of coal particles and in another in form of coal lumps. The entire process of making sponge iron is associated with various safety hazards. Modelling and optimization of a rotary kiln direct reduction. Details of rotary kiln pdf file process detail henan. Rotary kiln 1050 c kiln air at 30 c flue gas fly ash fines of iron ore at 900 oc kiln feeding iron ore.
Kiln temperature distribution for the base case the feed material bed enters the kiln at ambient temperature and rapidly heats up due to the hot gas in the freeboard. In sponge iron industry rotary kiln is the primary equipment. For questions or problems with your specific application please contact north american kiln. They are also used for roasting a wide variety of sulfide ores prior to metal extraction. For questions or problems with your specific application please contact north american kiln for assistance. Dri is also known as sponge iron because of its spongy micro structure. Characteristics requirement i inherent moisture content, percent by mass, max 4 ii ash, percent by mass, max 24 iii volatile matter percent by mass 2535 iv. Pdf analysis of temperature profile and % metallization in rotary. This work aims at developing a temperature profile by modelling the heat transfer phenomena happening inside the kiln. Cement kiln coprocessing high temperature treatment page 3 of 11 pesticides treatment technology fact sheet john vijgen, international hch and pesticides assoc iation and dr.
Study on accretion formation on dri kiln during spong iron. Coal, dolomite and iron ore or pellets are fed into one end of a rotary kiln, while sponge iron and char are withdrawn from the other end. This book comprehensively deals with the production of sponge iron in the rotary kiln. Dri is also known as sponge iron, it is a solidstate direct reduction process fig. Iron ore pelletizing, gratekiln process, magnetite oxidation, rotary kiln, process modelling. More than 100 dr processes have been invented and operated since 1920. Requirements for coal for sponge iron industry in case direct reduction in rotary kiln and in other reactors is 11860. I lardl and sponge iron is utilised in eastern asia and australia. A thesis submitted for partial fulfillment of the degree.
The original rotary cement kilns were called wet process kilns. Pdf 2 d model of sponge iron rotary kiln developed using cfd. Shape of produced sponge iron is in form of briquette having better density compared to dri from rotary kiln. Flow of materials in rotary kilns used for sponge iron manufacture. Thermodynamic process evaluation of a rotary kiln unit at. Reference lines should be identified for a basis of evaluating installation accuracy. A processstep benchmarking approach to energy use at industrial. The information collected and the background documents were synthesized by the secretariat. Computational fluid dynamics analysis of sponge iron rotary kiln. The major raw materials required for production of sponge iron by the rotary kiln process are. Based on the types of reductant used, dr processes can be broadly classified into two groups. Integrated steel plant tmt bar manufacturing plants.
Potential pollution problems met with in sponge iron production. Limestone, in small quantities, is also required to scavenge the sulphur. Recovery and utilization of waste heat in a coal based sponge. The raw meal was supplied at ambient temperature in the form of a slurry. Energy survey of the coal based sponge iron industry. Prasad and ray simulated flow pattern of air using fluent software in rotary kiln of a typical 100 tpd sponge iron process. Flow of materials in rotary kilns used for sponge iron.
Production process and technology for direct production of sponge iron from iron ore fines withough any need of either pelletisation nor sintering is offered adopted tunnel kiln and hematite iron ore fines. In the present work, several challenges faced in sponge iron production. Thermodynamic process evaluation of a rotary kiln unit at lkab kiruna. Modeling of rotary kiln for sponge iron processing using. A thesis submitted for partial fulfillment of the degree award of. The process of reducing the iron ore in solid form by reducing gases is called direct reduction. India is one of the countries where use of sponge iron contributes a large share in annual crude steel production. The present work identifies the basic features of burden movement in a rotary kiln. Recovery and utilization of waste heat in a coal based sponge iron. Regardless of rotary kiln size or configuration the basic principles outlined in this manual govern the reliable operation of every rotary kiln, calciner, dryer, incinerator, digester and cooler application. Pdf modeling of rotary kiln for sponge iron processing using.
Hot products used for rotary impact mill pdf rotary mill utiliing an impact reduction chamber and a vertical air flow classification. Industrial rotary kilns used in iron making are complex reactors having several functions. In this respect fixed bed tunnel kiln furnace are evolving as an alternative to rotary kiln process. Simulation of rotary kiln used in sponge iron process using ann. Typical 3d image of accretions in kiln 3 at tata sponge, developed. The initial chapters give a brief on the fundamental theories and basic principles of sponge iron production, commercially used dr direct reduction processes and physicochemical principles of sponge iron production.
Today india stands as the largest producer of coal based sponge iron through rotary kiln process using calibrated ore and non coking coal. In this pilot plant, a totally indigenous technology for production of. At first, the crude ore is mined by drilling or blasting at a depth of approximately. The process of the direct reduction of haematite in a rotary kiln is schematically described in the fig. A rotary kiln consists of a cylindrical, rotating body mounted. The reduction is carried out in a rotary kiln which is inclined and rotates at a predetermined range of speeds at a.
Cement kiln coprocessing high temperature treatment. General recommendation is to place reference lines every five linear feet. Sponge iron making is a process in which iron ore lumps typically 5mm18mm size are tumbled with a select grade of iron coking coal little dolomite inside an inclined rotary kiln and control combusted in the presence of air for about 12 hours before the products are air cooled, magnetically separated, screened and size wise in finished. Apart from this, primary and secondary airs are supplied to the kiln to initiate the combustion and reaction processes. Setting up of modalities for normative coal requirement in. Rotary kiln maintenance procedures rotary kiln lubrication. Energy balance in a rotary kiln sponge based iron making. Schematic flow sheet of coal based direct reduction process 1. These treatments can be applied to powders, granulates, suspensions and green bodies. A rotary kiln is a pyroprocessing device used to raise materials to a high temperature calcination in a continuous process. The amount of sponge iron in the charge mix varies from 090% depending on its.
Rotary kiln cement rotary kiln and sponge iron rotary kiln. Direct reduction process an overview sciencedirect topics. Raw materials, like iron ore and noncoking coal, are continuously fed whilst product sponge iron is continuously discharged from the downstream end, while the waste gases in. Formation and techniques for control of sulfur dioxide and. I know that the disadvantages of the vsk kiln are the inclusion of ash in the clinker, the problem with homogeneity of heat distribution, the low production. What is the maximum continuous shell temperature a kiln stands without permanent damage to the shell. Sponge iron process uses a rotary kiln for the reduction of high grade lump ores or pellets fig. Pdf industrial applications of rotary kiln in various.
Genetic algorithms based multiobjective optimization of. It is used to create cement, lime, metakaolin, titanium dioxide, alumina, iron ore pellets, and more. Coal is used as a reducent for sponge iron making in. Direct reduction processes with special emphasis on. Dear sirs, what is the difference between a clinker produced in a rotary kiln and the clinker produced in a vertical shaft kiln. The literature suggests that 5070% of the remaining so2 will be removed from exhaust gases when passed through an in. Iron ore the quality requirement of sized ore for sponge iron production can be classified into. This electric arc furnace can also use a form of iron known as sponge iron or there is no difference between the ecotech and alltech performance.
This product is known as direct reduced iron dri or sponge iron. As the focus of the present work is to study the kiln of sponge iron process, literature related to it is discussed here. All sponge iron units are operated the rotary kiln and operated with coal based. The input raw material such as iron ore, noncoking coal with high reactivity and the fluxing materials.
Analysis of temperature profile and % metallization in rotary. Looking forward to the need of developing coalbased sponge iron technology in india, a country having no significant resources of either coking coal or natural gas, the research and development division of the tata iron and steel company limited tisco set up a rotary kiln based direct reduction pilot plant in 1975. Plant details mgm group in the first phase one 350 tpd rotary kiln and 8mw power plant have been missioned and are operating smoothly sponge iron plant sponge iron plant or direct reduction plant drp is designed to produce 350tons of sponge iron per day in a rotary kiln using iron ore, non coking coal and dolomite as the raw materials. Modelling and optimization of a rotary kiln direct. A rotary kiln is a pyroprocessing device that raises materials to very high temperatures in a continuous process.