Additional Use of Coke Oven Gas

Around 25 to 30% of the weight of the coal charged to coke ovens is driven off as effluent gases rich in volatile matter and moisture. After drying this raw gas and separating tar, light oil and sulphur fractions (which have values themselves), coke oven gas (COG) is obtained.  This gas has a heating value between 17 – 20 MJ/Nm3 and is generally used for coke oven heating, heating of other furnaces and for power generation, both internally and externally.  Although COG recovery is performed in most plants, it still offers a considerable potential. 

According to a 2007 study by International Energy Agency (IEA, 2007, p. 111), approximately 70% of the COG was used in iron and steel making processes, 15% for coke oven heating, and 15% for electricity production.  It was stated that by using more of the COG for power generation (preferably combined with more efficient combined cycle power generation techniques that can provide efficiencies of around 42% techniques as opposed to those based on steam cycles - with an average efficiency of around 30%) improvements in energy efficiencies can be realised.  

Chinese flag Indian flag US flag Although COG recovery is performed in most plants, this technology is regarded to have high expansion potential in China, India and the United States.

Development Status Products
Commercial
steel, coke, iron

Additional Use of Coke Oven GasCosts & Benefits

Parent Process: Coke Making
Energy Savings Potential

Coke oven gas with a heating capacity of 6 to 8 GJ can be recovered for every ton of coke produced. (IEA, 2007)

Chinese flag In China, the potential of recovering COG from stand-alone coke enterprises was estimated to be around 250 PJ in 2005.

CO2 Emission Reduction Potential

Chinese flag In China, CO2 emissions can be reduced by 25 million tons by recovering COG from stand-alone coke enterprises located near coal mines

Costs

By using COG as supplementary fuel in blast furnace, a steel mill in the US was able to save US $6 million annually.  The project required an investment of around US $6.1 million, and had a payback time of just over one year. 

Additional Use of Coke Oven GasSchematic

Additional Use of Coke Oven Gas Publications

Energy Efficiency Improvement and Cost Saving Opportunities for the U.S. Iron and Steel Industry

The U.S. Environmental Protection Agency’s (EPA) energy guide, Energy Efficiency Improvement and Cost Saving Opportunities for the U.S. Iron and Steel Industry, discusses energy efficiency practices and technologies that can be implemented in iron and steel manufacturing plants. This guide provides current real world examples of iron and steel plants saving energy and reducing cost and carbon dioxide emissions.

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Additional Use of Coke Oven Gas Case Studies

Additional Use of Coke Oven Gas Conference Papers