Development of an O2 Enriched Furnace System for Reduced CO2 and NOx Emissions for the Steel Industry (9806)

The objective of this work is to develop an O₂-enriched furnace system that will reduce CO₂ and NO_X emissions under typical steel-industry conditions.

The combination of the latest burner technology for fuel-air combustion with O₂-enrichment will result in both lower NO_X and CO₂ emissions. The issues that will be addressed by this work include: (1) the optimum configuration of the ultra-low NO_X burner for high energy efficiency (low CO₂), low NO_X emissions and even heat distribution; (2) the effect of air infiltration on furnace performance during O₂-enriched combustion; (3) the effect of O₂-enriched combustion on steel scale formation in reheat furnaces.

One of the most recent approaches to reducing NO_X emissions and increasing combustion efficiency involves the use of oxygen-enriched air. The resulting lower nitrogen content in the oxidizer stream yields higher combustion temperatures, which can improve energy efficiency. In order to achieve NO_X reductions with natural gas fuel, there must be a balance between the increased kinetic rates at higher temperatures and the nitrogen content in the oxidizer stream (the source of nitrogen in the NO_X). Determining optimum O₂-enrichment levels is one of the primary objectives of this work. An added benefit of this technology is that, with lower fuel requirements to maintain a given furnace temperature, CO₂ emissions can be reduced significantly. Tests and development work will be conducted on the Center for Advanced Gas Combustion Technology’s (CAGCT) research furnace at Queen’s University. The furnace tests will be performed with a burner developed jointly by the CAGCT and the Canadian Gas Research Institute (CGRI).

Work Plan

Tests and development work will be conducted on the Center for Advanced Gas Combustion Technology's (CAGCT) research furnace at Queen's University. This furnace has a nominal working volume of 1 x 3 x 5 m (2 MW). Initially it was built for a research project with the steel industry in Canada. The CGRI burner employs internal recirculation to reduce NO_X with an array of alternating air and fuel ports arranged in a circle. The air and fuel ports are at different angles to the burner axis. With O₂-enrichment, modifications to the existing burner design will be required to identify suitable oxidizer and fuel inlet conditions (port angles and diameters). Prior experience with this burner in our furnace indicates that the "air" port diameter should be reduced to a suitable value and the fuel jet angles varied to find best operating conditions. The effect of firing rate, heating loads (exposure of cooling panels in the furnace floor), and "air" preheat level will then be examined at different O₂ enrichment levels . Specific tests will also be performed to examine the impact of air infiltration on NOX emissions. The furnace instrumentation permits measuring the concentrations of CO, CO₂, O₂, CH₄, NO_X and unburned hydrocarbon in the products of combustion, as well as the local gas temperatures, wall temperatures, and radiative fluxes. The furnace is also equipped with sample ports for inserting steel samples to monitor scaling rates and these measurements will be conducted through most of the burner trails in this work.

Project Schedule

Cost Sharing

Air Liquide
BOC Gases
Dofasco Inc.
Fuchs Systems