Kerala Sponge Iron Limited is a public company incorporated on 27 January 2005. It is classified as a non-government company and registered with the Ernakulam Companies Registry. Its authorized share capital is Rs. 160,000,000, the actual paid-up capital is Rs. 158,400,000. Involves basic steelmaking
Kerala Sponge Iron Limited’s Annual General Meeting was last held on September 30, 2013 and its balance sheet was last filed on March 31, 2013, according to the Ministry of Corporate Affairs (MCA).
The production methods of sponge iron are very different as you know. The iron-made blast furnace is a circular shaft furnace with a height of about 30m and a maximum internal diameter of about 10m. The hearth is a steel shell lined with refractory materials, almost all of which are clay bricks.
The bricks used for the hearth and crucible are fire clay bricks of the highest quality – a hard and dense super material. Some furnace liners are made from carbon blocks. The thickness of the refractory brick layer is about 1m at the belly and about 1-2m at the upper part of the shaft.
The bottom of the crucible is made of high-quality refractory clay bricks, with tight seams to prevent molten metal from seeping up from the bottom, with a thickness of 2-4m.
There are 10 to 16 fans equally spaced along the circumference under the belly, through which preheated air (1000-1100 °C) enters the furnace at a pressure of 2 kg/sq.cm.
The hearth is the part of the furnace placed between the mantle and the upper part of the crucible; it is the melting zone and is the hottest part of the furnace (1900-2000°C). As the hot reducing gas moves up, it heats the solid charge and participates in different reactions in different areas of the furnace.
Steel is a product of a large and technologically complex industry with a strong material flow forward and backward. The Indian steel industry has reached a sufficiently mature level in terms of technology absorption, product development, and productivity improvements. India ranks second in the world in both production and consumption (WSA, 2020). The Indian steel industry is large, medium and small in scale with varying degrees of vertical and horizontal integration. It is very diverse and consists of state-of-the-art factories with an extensive and varied product range.
Steelmaking in the country follows various routes such as blast furnace basic oxygen furnace (BF-BOF), coal-based direct reduction (DR), gas-based DR, electric induction furnace (EIF) and electric arc furnace (EAF). Based DR is unique in the Indian steel industry as it mainly caters to local steel needs.
The uniqueness of DRI technology is driven by the availability of domestic coal reserves and the lack of adequate domestic gas supply and coking coal in the country. Like any industrialized economy, the steel industry is vital to the Indian economy. It contributes about 2% to the country’s GDP and employs about 2.5 million people in the steel and related industries.
India’s total annual direct reduced iron (DRI) capacity in 2020-21 is 47.85 million tons (Mt) and production is 34.15 Mt. There are 285 DRI plants in India, most of which use coal-based rotary kilns. DRI units have installed capacity in the range of 50-500 tons per annum. day (tpd), with single or multiple furnaces.
Most DRI plants use 100 t/d furnaces. The total installed capacity for coal-based DRI units is 36.74 tons, while the total installed capacity for gas-based DRI units is 11.10 tons, of which 2 use the gasification route (syngas and COREX gas), 3 use the natural gas route, Supplemented with COREX /coke oven gas.
kerala sponge iron limited company
Karala sponge iron limited company started its work in 2005 and has its own share in the production of sponge iron in India. Direct reduction of iron can be defined as the process of direct production of metallic iron by reducing solid iron ore at temperatures below the melting point of iron.
The reduction of iron ore can be achieved by using carbonaceous materials (eg non-coking coal) or a suitable reducing gas in the form of reformed natural gas. The reducing gas in the DRI process consists mainly of hydrogen and carbon monoxide.
The solid iron produced in this way is called directly reduced iron. DRI looks like a honeycomb structure and looks like a mushroom-like structure under the microscope, so it is also called “sponge iron”. DRI plants in India follow one of these approaches and obtain the reducing agent in the form of hydrogen or carbon monoxide during the reduction of solid coal, coal gasification or natural gas.
Most coal-based DRI production in India has tailored plant specifications using one of the standard DRI processes such as SL/RN, KRUPP-REIN, KRUPP-CODIR, DRC (DAVY Reduction Corporation), ACCAR, DRC, or adapted from these classes like TDR (Taigang Direct Reduction), SIIL (Indian Sponge Iron Limited), JINDAL, OSIL (Odisha Sponge Iron Limited) and Popuri Engineering Limited.
Solid coal-based DRI production uses horizontal rotary kilns in the production process. The furnace is equipped with a 150-200 mm refractory lining to protect the furnace body, which slopes 2.5%-3.0% towards the outlet end.
Combustion air requirements for the feed are provided by fans along the length of the heating zone. The main raw materials used in the production of sponge iron include iron ore (hematite or Fe2O3), non-coking coal, and limestone/dolomite.
Hematite rich in iron content of 65% or more is the preferred choice for iron sponge mills. Iron ore is available in lumps and pellets. Most DRI plants in India use smaller-capacity rotary kilns (100 t/d or less).
Iron ore and non-coking coal are crushed to the desired size in the crusher. The required proportions of iron ore, coal and dolomite are continuously fed into the furnace from the feed end through a gravimetric feeder. The raw material moves along the length of the oven in a preset rotation. Secondary air is blown into the furnace through an air duct located along the length of the furnace.
The initial heating of the furnace refractory is carried out at the outlet end of the furnace using a fuel oil system above the ignition temperature of the coal.
The temperature in the different heating zones is measured and controlled using thermocouples mounted on the oven. Fine coal is injected at the outlet end of the furnace to meet the additional carbon demand of the reaction.
As the charge moves along the length of the furnace, it gradually absorbs heat from the hot gases flowing in the opposite direction of the charge. The preheating zone, which is approximately 30% of the oven length, is where moisture and volatiles are removed from the feed mixture. The necessary heat in the preheating zone comes from the part of the coal combustion.
Cooling of sponge iron
Discharges of sponge iron and solid waste (including charcoal, spent limestone/dolomite) are diverted to water-cooled rotary coolers. The slope of the rotary cooler is approx. 2.5%–3%. Spray water to the rotary cooler shell to indirectly reduce the furnace temperature to about 100-120℃. This helps avoid reoxidation of sponge iron when exposed to the atmosphere, as it is very unstable at high temperatures.
Electromagnetic separation and shielding The material discharged from the rotary cooler is transported by a conveyor to shield fine and coarse materials.
The discharge material with a particle size of less than 3 mm is separated, and the iron sponge and carbon and other impurities are separated through an electromagnetic separator. Sponge iron is sieved by size fraction to separate lumps and fine particles.
The waste gas produced by the rotary kiln flows into the feed in a countercurrent direction, exits from the feed end of the rotary kiln and passes through the gravity settling chamber.
It then passes through a post-combustion chamber (PCC) or post-combustion chamber (ABC), where the remaining carbon monoxide in the exhaust is converted to carbon dioxide. The flue gas is passed through a wet scrubber or a combined gas conditioning tower to reduce the flue gas temperature below 150°C. The cooled exhaust gas passes through an electrostatic precipitator (ESP) before being discharged through the stack.
kerala sponge iron limited
The last meeting of the kerala sponge iron limited was held in India in 2013. Kerala Sponge Iron Limited is majorly in Manufacturing (Metals & Chemicals, and products thereof).
Gas-based DRI manufacturing processes include:
(i) using gasification or reforming pathways, as appropriate, to generate and purify reducing gases such as hydrogen and carbon monoxide; and
(ii) reduction of iron ore in a vertical shaft furnace. The vertical shaft furnace is the heart of the gas-based DRI process and consists of a cylindrical, refractory-lined vessel. It uses reducing gas from natural gas, syngas from coal, coke oven gas or waste gas from the COREX process.
The shaft furnace works on the principle of a counter-current system, where iron ore (charge) is moved downwards by gravity and reduced by the upward-flowing reducing gas.
The iron material is fed from the top of the furnace and the sponge iron is taken out from the bottom of the furnace. The syngas is treated to enrich hydrogen and carbon monoxide, which are then preheated and used in the shaft furnace.
The reducing gas is passed through the landfill, and the waste gas is recirculated after being heated and converted into a mixture of hydrogen and carbon monoxide in a reformer, where it is heated to approx. 950°C to ensure a suitable reduction rate. reaction.
Gas-based DRI does not require magnetic separation due to the absence of contamination from non-magnetic materials. The gas-based process is very flexible and the final yield can be produced in three different product forms, depending on specific requirements, including cold DRI, hot briquette iron (HBI) or hot DRI.
There are three main gas-based processes that can be used in DRI production: (1) the HYL or Energiron process, (2) the MIDREX process, and (3) the PERED process. Most DRI plants in India follow the fixed coal-based route. In light of this, this technical compendium focuses primarily on energy-saving technologies and practices associated with rotary kiln-based DRI processes using solid coal.
A key performance indicator (KPI) is a measurable parameter that indicates the effectiveness or efficiency of a system. KPIs indicate the potential for performance improvement relative to a design or optimal performance value. KPIs for the direct reduced iron (DRI) process include capacity utilization, yield, specific energy consumption (SEC), material balance, and energy balance. This section provides KPIs for the production of direct reduced iron or sponge iron using solid coal in the process.
The performance of sponge iron depends on factors such as tumble index, wear index and thermal degradation. The degree of metallization of the iron ore and the loss of iron in the process are also factors that determine the yield. The loss of iron can occur in a number of ways, such as tail gas entrainment, degree of adhesion, magnetic separation, loss of non-separable iron in the carburization, depending on the level of fines in the feed iron ore.
the yield of the rotary kiln is the ratio of the total sponge iron production to the feed iron ore. It depends on the iron content, thermal decomposition of the iron ore and operating practices.
If most iron ore properties are at optimal levels, then optimal yield equals iron content. Any deviation in yield may be related to ignition losses and operating practices. The higher the percentage of sponge iron, the more productive the process, and vice versa, for a given feed.
If there are no losses in the process, the maximum output from the DRI process will be equal to the percentage of iron in the ore. As a best-case illustration, approximately 1.55 tons of iron ore, at 64% iron, yields up to 1 ton of sponge iron.
The performance of the DRI industry is largely determined by the overall utilization of installed capacity. It is the ratio between DRI production and total installed capacity.
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