Project location: CanmetENERGY Ottawa, Ottawa, ON
Timeline: 5 years (2023-2028)
Program: Bioenergy
Project description
The project investigates the potential for fuel switching and oxyfiring (using oxygen instead of air as the oxidant for combustion) in the rotary kiln for the kraft pulp mill, mineral lime processing and cement manufacturing.
The rotary kiln uses a burner to heat the solids to the reaction temperature. The solids include calcium carbonate that decomposes to calcium oxide (lime) and carbon dioxide. The flue gas therefore contains a high concentration of carbon dioxide from both fuel and solids. Oxy-firing is an option to produce a flue gas that can be sent for sequestration with minimal additional processing. Oxy-firing replaces the air for combustion with oxygen and recycled flue gas, removing nitrogen and increasing carbon dioxide. The higher carbon dioxide concentration in the kiln can inhibit the decomposition of the calcium carbonate. The inhibition of reactions by elevated carbon dioxide in the gas, primarily calcination, will be investigated experimentally using a thermogravimetric analyzer (TGA) with varying carbon dioxide concentration. A mathematical model of the kiln, including combustion and solids reaction, is being developed to calculate the effect of fuel switching and burner management on solids product quality with the objective of producing a digital tool for industry to use. Finally, a techno-economic analysis (TEA) will be performed comparing the cost of oxy-firing retrofit to the benchmark amine (MEA) scrubbing carbon capture and storage (CCS) technology.
Project activities
Determine the operating temperature window for calcination (lime processing) and clinker formation (cement) without overheating when recycling flue gas.
Develop the burner management strategy for the oxy-fired flame with flue gas recycling for effective solids processing in lime kilns and cement kilns.
Compare the economics of CCS by oxy-fired retrofit and MEA scrubbing for CO2 capture.