Coke Dry QuenchingCosts & Benefits
|Parent Process: Coke Making|
|Energy Savings Potential||
The most efficient coke ovens use CDQ and may use up to 40% less energy.
Approximately 1.5 GJ heat/t-coke (as ~ 400 - 500 kg high temperature steam/t-coke) and 0.55 GJ electricity/t-coke can be recovered.
For a plant with 450 000 t/y coke capacity (~1 million t/y BF capacity), 450 GWh/y of steam and around 150 GWh/y of electricity can be produced.
In China energy use for coking has decreased from 5.6 GJ/t-coke to 4.9 GJ/t-coke between 1995 and 2000, and further decreased to 4.2 GJ/t-coke by 2004, thanks to installation of more than ten coke dry quenching and other advanced quenching technologies.
|CO2 Emission Reduction Potential||
CO2 savings in excess of 100 000 t/y are estimated by converting two 25 t/h capacity quenching systems from wet to dry (Climatetech Wiki, 2011)
Given about 300 Mt coke production without CDQ and savings of 600 g CO2/kWh, global CO2 emissions reduction potential is about 25 Mt CO2.(IEA, 2007)
Retrofit capital costs are 109.5$/ton coke. The cost of a 3-chamber plant can be estimated to be in the range of €60-70 million including equipment and installation costs.
In Europe equipment costs for a 2 million ton-coke/year plant are estimated to be €70 million. Depending on the electricity costs, the payback time can be 3 years - if all the steam is used for electricity generation. (IPPC BREF, p. 276)
In Japan, installation of a CDQ for a 450 000 t-coke/y capacity plant required ¥ 3 billion in equipment and ¥ 500 million in construction costs. With an electricity price of ¥17.99/kWh, approximate payback time was 3.6 years [1 ¥ = US $0.1257] (NEDO, 2008. p.67)
By converting two 25 t/h capacity quenching plants from wet to dry systems with 15 MW electricity generaton connected to each, US $9 million savings in electricity, and US $1 million in water related costs are estimated. (Climatetech Wiki, 2011)
Coke Dry QuenchingSchematic
Coke Dry Quenching Publications
This revised 2008 version of the publication from New Energy and Industrial Technology Development of Japan includes information on innovative Japanese technologies for energy efficiency and for the reduction of CO2 emissions.
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.