Frequently Asked Questions

» What are the primary pollutants from a rotary kiln DR process ?

The gas from a coal based rotary kiln would contain CO, CO2, SOx, NOx, hydrocarbons,trace metals and particulate matters.

» What are the other potential pollution problems in coal fired rotary kilns ?

(i) The residual poly nuclear aromatic hydrocarbons (PAHs) formed in ore-coal bed. (ii) The residual PAHs from the combustion of oil and coal above the ore-coal mixture.

» How are exit gases from a rotary kiln treated ?

The exit gases from rotary kiln are combusted in an afterburner to reduce the concentration of reduction gases and unburnt hydrocarbons. This is normally followed by a gas conditioning tower (GCT) and electrostatic precipitator (ESP) or by a combination of cooler and fabric filter. In certain cases, wet scrubber might have been used.

» What is a typical dust concentration from exit gases in a gas based DR process ?

50 - 100 mg/Nm³.
Please see the detail table in this notification

» Can coal bed methane (CBM) be used as a supplementary fuel from discharge end in a rotary kiln ?

Yes. It can be used in the same manner as producer gas.

» Can CBM be used as fuel and reductant in a gas based DR process ?

Yes, it can be used provided it has at least 95% methane.

» What are the typical ways of pollution control for sponge iron units ?

First, right from the project implementation stage stress need to be given to pollution control and maintenance of clean and green environment in and around the plant. Establish a treatment procedure for unburnt particles and gases coming out of Kiln, so that it releases clean gas to the atmosphere. Use bag filters at as many steps as possible. Suppress micron sized dust particles with atomized water spray or any other latest technologies. Plan from the very beginning reuse and recycle of waste solid products as well as recovery of heat from the exhaust gases for generation of captive power. Avail technical expertise from ECAC.

» I want to set up a sponge iron unit in West Bengal. What is the procedure for obtaining clearance ?

If the capacity of your plant is less than 200 TPD then clearance from State level committee is required. If the capacity of your plant is more than 200 TPD then clearance from Central level committee is required. Please click here http://www.ecacwb.org/node/19

» Do I have to apply for Consent to Establish ?

Yes. Consent to Establish application has to be submitted after obtaining environmental clearance to the WBPCB EIM Cell. Click for application receiving offices. http://www.ecacwb.org/node/17

» Is there a siting criteria for sponge iron units ?

Yes. The siting criteria for sponge iron units is given http://www.ecacwb.org/node/56