ROTARY KILN

(Coal-based DRI Plant)

Direct Reduced Iron (DRI), which is also known as sponge iron, is the product of the direct reduction of iron ore in the solid state by carbon monoxide and hydrogen derived from natural gas or coal.

Sponge iron can be used by Electric Arc Furnace (EAF) steelmakers as a part of their metallic charge, along with normal mill returns and, if required, with certain amounts of non – selected cheap scrap. Sponge iron is cost-effective as it allows EAF steelmakers to produce tight specifications steels.  

WHY SPONGE IRON IS BECOMING POPULAR

• Its quality and variations in composition are captivating.
• Its even composition, size, and high bulk density are incomparable (to scrap).
• It is capable of forming protective layer of foamy slag in the bath.
• The steel produced requires low refining.
• Scraps aren’t common again the way they used to be.
• Sponge iron can be produced with non-coking and low quality of coal.
• It enables steelmaking to dilute metallic residuals in scrap.
• Sponge iron is an excellent feedstock for the electric furnaces used by mini mills because it has almost the same iron content as pig iron, typically 90–94% total iron (depending on the quality of the raw ore).
• The direct reduction process uses pelletized iron ore or natural "lump" ore. One exception is the fluidized bed process which requires sized iron ore particles.
• The direct reduction process can use natural gas contaminated with inert gases, avoiding the need to remove these gases for other use.
• The DRI method produces 97% pure iron.

QUALITIES OF PARAS DESIGN

Paras’ design gives offers the operator the following advantages:

• Effective plant: Paras design has highly efficient and effective and process that give great waste heat recovery.
• Versatility: The design is versatile and can be used for different grades of raw materials.
• High combustion efficiency: Paras design has high combustion efficiency enabled by gas monitoring system.
• Modern instrumentation: Paras design also has advanced instrumentation and automation used to reduce consumption of utilities.
• Pollution-free: Paras’ plant has most-modern dust suppression and collection system and is pollution-free.
• International standard: The equipment and project are designed to meet international standards, hence, they perform optimally and are long-lasting.
• Plant layout: Paras plant has highly engineered layout which enables minimal material handling and smooth material flow.
• Reputation: Paras is reputed to be a distinguished designer, producer and user of Sponge Iron.
• Highly rated facility: Paras has facility used to substitute natural gas for some parts of coal.

PROCESS OF COAL BASED DRI PLANT

Iron ore, coal and lime stone or dolomite are introduced into the preheated reactor at controlled rates through a feed pipe mounted through the feed end housing.  

The rotation of the reactor is used to promote the mixing of the materials in the rotary kiln, and the materials are mixed and contacted for the reaction. The kiln head coal combustion produces a large amount of heat, and the heat is transmitted to the material through flame radiation, convection of hot gas, and kiln brick. The material moves forward in the kiln depending on the inclination of the kiln cylinder and the rotation of the reactor.