Process

DIRECT REDUCTION SPONGE IRON PLANT:

Raw Material preparation section:

The in coming raw materials are store in the area bench marked for each material in the stock yard. The iron ore is fed to the iron ore circuit which consists of screen and one crusher for the over size material to be crushed. From the ground hopper the iron is fed to the screen. The over size material goes to the crusher screen. The over size goes to the crusher where it is crushed and returns back to the screen. The coal is graded into different sizes and are fed to the respective hoppers in the stock house. The lime stone is directly conveyed to the stock house bin.

Main Reduction Plant

The main plant consists of the kiln, cooler and the waste gas handling area. The sized iron, coal and lime stone are fed to the kiln in a pre-determined in the ratio. The kiln is cylinderical vessel of 4.80 mts in dia and 85mts long. It is inclined at 1.470. There are nine shell air fans mounted on the top of the kiln. These fans supply air to the kiln to maintain required temperatures. The Coal is also blown from the discharge end of the kiln to maintain the temperatures.

The material is gradually heated to about 10000C where the iron ore is reduced to sponge iron. The hot material goes to the cooler which is also a cylindrical vessel of 3.6 mts dia and 50 mts long. It is also inclined at 1.470. water is sprayed on the top of the shell to cool the material. The gasses from the kiln flow in the counter currently. The dust in the gasses settle in the dust settling chamber and then any unburned components will be burned in the after burner chamber. The gasses are then pass through the waste heat recovery boiler where they are cooled to below 2000C. The cooled are then subjected to electro static precipitation where all the dust is settled.

Product Handling

The product coming out of the cooler contains some unburned coal along with the sponge iron. The cooler discharge material through the double pendulum valve is send the screen where the coarser and finer particles and seperated and then they are fed to the magnetic seperaters. The sponge iron being magnetic wiil be separated from the unburned coal which is non magnetic. The sponge iron and char are fed to the respective bins by the conveying system.

CAPTIVE POWER PLANT

The power plant is of 35.0 MW will be set up for captive consumption. This will have two Waste Heat Recovery Boilers & 1 No. of AFBC Boiler, Turbo- Generator and Ash handling System.

Waste Heat Recovery Boilers:

The gases coming out of the kiln are at 10000 C and contain lot of sensible heat, this heat is recovered for power generation. The gases are made to pass through the furnace chamber where the dust in the gases settles and the heat is extracted from the gasses in the water walls. The gasses then pass through the super heater coils and the economizer where the heat is further extracted and the out going gasses are let into the Electrostatic precipitator at 1600C.

Turbo—Generator:

The turbo-generator will have a capacity of 35.0 Mw. The turbine will be multistage steam turbine. Special provisions are given for taking care of the variation in the utilization of power generated. The generator has an output of 11Kv and will be used for supply of power to all the plants i.e. Iron ore fines benefaction plant, pellet plant, Sponge Irion Plant, Steel Melting & Rolling Mill section etc.

Ash Handling:

The fly ash produced by the combustion of the coal and char will be subjected to the dust collector which will remove all the ash from the gasses with ESP before being let off to the atmosphere. The ash will be collected, dried and used for brick manufacturing to be used in building construction there by avoiding any pollution hazard.