Professor John Dennis

Combustion group

Research in the sustainable generation of energy by gasification and combustion is motivated by the link between global warming and the release of CO2 from fossil fuels used for electricity generation. The focus is primarily on fluidised bed reactors, since they are important in novel cycles using fossil fuels for power generation, designed to capture and sequester the CO2. Fluidised combustors are also important in power generation using biomass fuels, since they give huge advantages over other combustors in (i) tolerance to changes in fuel, (ii) the catalysis of reactions or capture of pollutants by the bed material, (iii) high heat transfer, and (iv) economic operation at relatively small scales. The latter will facilitate smaller, distributed, power plants, fuelled by locally-produced biomass, especially in the developing world. Fluidised beds can present intractable operational problems, difficult to solve because knowledge of the fundamentals is still imperfect. Accordingly the Research Group has three major, uniquely-interrelated, strands of activity:

1. The combustion or gasification of fossil and renewable fuels in novel power cycles capable of capturing their carbon content as a pure stream of CO2 suitable for sequestration.
2. The physics of fluidisation, investigated using combinations of new (e.g. Magnetic Resonance Imaging) and existing (e.g. Particle Image Velocimetry) experimental techniques.
3. Discrete Element Modelling of fluidised beds, validated by experimental measurements from (2). 
4. Control of emissions from fluidised bed combustion and gasification.
5. Energy-related reaction engineering, e.g. extraction of fuel-like molecules from algae.

We publish regularly in these fields, including attendance at major international conferences, and have significant links with researchers around the world.