Coal Gasification utilises the chemical energy present in coal and represents the cleanest and most efficient method for producing sponge iron. In comparison, the conventional steelmaking process via Blast Furnace emits ~1.85 tonnes of carbon dioxide, a quantity that can be significantly reduced by adopting the Coal Gasification technology. This ground-breaking advancement holds the potential to decrease dependence on coal imports while effectively addressing environmental challenges. Coal Gasification technology showcases immense promise, particularly in countries like India, where non-coking coal is abundantly available.

Background

Direct reduced iron (DRI), more commonly known as sponge iron, is produced from direct reduction of iron (in the form of lump, pellets or fines) by reducing gases produced from natural gas or coal. This reduction takes place at the temperature range of 800-1050°C when reducing gases (primarily hydrogen and carbon monoxide) react with the iron oxides to produce iron. The degree of metallization, defined as the extent of conversion of iron oxide into metallic iron, is 92-96% in a typical DRI process. This high percentage of metallization makes DRI a highly suitable input for steel making. The specific investment and operating cost of DRI plants are low compared to integrated steel plants and are more suitable for many developing countries where coking coal is scarce. This holds true for India, where most of the coking coal has to be imported.

Challenge

Natural gas-based DRI is a highly efficient technique for manufacturing sponge iron and has a lower environmental impact. However, the availability of natural gas is a big constraint. At Jindal Steel & Power's (JSP) Angul steel plant, the DRI - BF - Electric Arc Furnace route has been adopted for manufacturing steel.

Our Solution

To overcome the challenge of the non-availability of natural gas, a coal gasification plant was set up. It uses high ash coal, available near the site, and converts it into synthesis gas or Syngas. It is the first plant of its kind in India and only the 2nd in the world.

The Syngas, produced through the gasification process, contains methane, carbon monoxide, carbon dioxide, hydrogen, and water vapour. This process has a lower impact on the environment as compared to the coal combustion process. During the gasification process, the carbon dioxide emitted in the process is entirely absorbed back into the process, and the hydrogen sulphide is entirely used for sulphur production.

Capital expenditure for setting up the Syngas plant was high and had a gestation period of three years. However, this high investment is offset by the improved energy efficiency of the system, as compared to the conventional steel production model, and reduced environmental impact in the long run. Another added advantage Jindal Steel & Power (JSP) explored was the utilisation of waste. All seven by-products of the Syngas plant are recycled through internal use or sold to external parties. This ensures the health and safety of employees as well as local communities and helps to protect the environment.