LLE: Oxy-fuel Combustion in Kraft Pulp Mills for Carbon Sequestration (Nikolai DeMartini, University of Toronto)

Abstract

The concept of oxy-fuel combustion involves using O₂ separated from air to burn a fuel to generate a CO₂ rich stream that can then be sequestered. However, if only O₂ is fed into the boiler, the combustion temperature will be too high. In practice, flue gas would need to be cooled to condense out water and then a part of the CO₂ rich flue gas is recycled and mixed with the O₂ as the feed oxidant to the combustion system. The remaining CO₂ rich gas (>90% CO₂) can be compressed and sequestered or further purified and used as new uses for CO₂ are developed.

There are three different combustion systems found in pulp mills:

• Kraft recovery boiler for burning black liquor
• Lime kiln for driving CO2 from CaCO₃ to generate CaO
• Biomass boiler where bark and reject wood from pulping are burned

In this presentation I will talk about the early research in oxyfuel combustion in kraft recovery boilers and lime kilns and some of the process and process chemistry implications of transitioning from traditional combustion with air to oxyfuel combustion.

Speaker Bio

Nikolai De Martini is an Associate Professor of Chemical Engineering and Director of the Pulp and Paper Centre at the University of Toronto. He joined the faculty in 2017. Prof. De Martini earned a PhD in Chemical Engineering for work on nitrogen and sulfur chemistry in kraft recovery boilers at Åbo Akademi University in Turku, Finland. He currently leads the industrial consortium Effective Energy and Chemical Recovery in Pulp and Paper Mills which is supported by pulp and paper companies in Canada, the United States, Brazil, Chile, Finland and Sweden.