Post Combustion of EAF Flue Gas

Post combustion is a process allowing for utilization of the chemical energy in the CO and H2 evolving off the steel bath through the injection of oxygen. This energy is used to the steel in the EAF ladle or preheat scrap – up to 300-800°C. EAF operations that involve large amounts of charged carbon or pig iron are particularly suitable for implementation of CO post-combustion technology. Besides reducing energy demand, the technology also improves productivity and helps to optimize the benefits of oxygen and fuel injection.  

Post combustion also helps to optimize the benefits of oxygen and fuel injection. For cases where the heat is to be used in the furnace, It is critical that post-combustion is done early at melt down while the scrap is still capable of absorbing the evolved heat. The injectors should be placed low enough to increase CO retention time in the scrap in order to transfer its heat. The post-combustion oxygen flow should have a low velocity to promote mixing with the furnace gases and avoid both scrap oxidation and oxygen rebound from the scrap to the water cooled panels. The injectors should also be cooled extremely well as the post-combustion area often gets overheated. In order to distribute the chemical energy uniformly and to make its utilization efficient, it is preferable to bifurcate the post-combustion oxygen flow and to space out the injectors in the colder areas of the shell. (Worrell, et al., 2010. p. 93).

Development Status Products
Commercial

Post Combustion of EAF Flue GasCosts & Benefits

Parent Process: Electric Arc Furnace
Energy Savings Potential

For a particular post-combustion system, electricity savings ranged from 6 to 11% depending on the operating conditions (Worrell et al., 2010. p. 93).

CO2 Emission Reduction Potential

Energy savings will result in reduced emissions.

Costs

In a particular application tap-to-tap times were decreased by 3 to 11% depending on operating conditions (Worrell et al., 2010. p. 93)

Post Combustion of EAF Flue 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.

Page Number: 

93

The State–of-the-Art Clean Technologies (SOACT) for Steelmaking Handbook

 

The State–of-the-Art Clean Technologies (SOACT) for Steelmaking Handbook is developed as part of the Asia-Pacific Partnership on Clean Development and Climate program and seeks to catalog the best available technologies and practices to save energy and reduce environmental impacts in the steel industry. Its purpose is to share information about commercialized or emerging technologies and practices that are currently available to increase energy efficiency and environmental performance. 

Page Number: 

83