Department of Chemical Engineering >  People > Retired academic staff

Prof Allan Hayhurst

BA, Natural Sciences, University of Cambridge, 1960
MA, PhD, Physical Chemistry, University of Cambridge, 1964
ScD, Chemical Engineering, University of Cambridge, 1992
FIChemE, FEI, CEng, MRSC
Lecturer, Senior Lecturer, Sheffield University, 1972-1979
Fellow of Queens' College 1964-1972; 1979-2004
Life Fellow 2004-
Emeritus Professor 2004 -
Honorary Professor, Krakow Technical University, 2004-
Chairman, British Section of The Combustion Institute, 2006-

One area of research covers heat and mass transfer, as well as chemical kinetics, the aim being to elucidate mechanisms for the production of pollutants associated with combustion and also their removal. The latter area covers the kinetics of reactions between gases and solids (usually porous ones). Much of this work is done in collaboration with the Combustion Group, together with Dr J.S.Dennis and Prof J.F.Davidson. The modelling of oscillating reactions, with and without natural convection, continues with Dr S.S.S. Cardoso

Particles in flames (with Dr Dennis)
A variety of metallic species in flames form solid nano-particles. The processes of particle formation and growth are currently under study.

Combustion and gasification of coal and waste materials, biomass and sewage sludge (with Dr Dennis and Prof Davidson)
During combustion, coal undergoes thermal decomposition into gases and a solid. The kinetics of devolatilisation are under study. Under oxygen-rich conditions (combustion) coal produces SO₂ and SO₃; under oxygen-lean conditions (gasification) it produces H₂S. A fluidised bed can contain CaO (e.g. from added limestone) which removes SO₂ or H₂S. The kinetics of all these processes are being studied. In addition, the gasification of waste materials (e.g. sewage sludge) is under investigation, as also are the kinetics of the reaction between oxygen and a solid carbon.

Combustion and other mechanisms in fluidised beds (with Dr Dennis and Prof Davidson)
We are investigating the following problems:

1. Fluidised bed combustors contain an inert solid, e.g. sand. Gases usually burn above the bed or in the bubble phase.
2. The rate of oxidation of char has an unknown order with respect to oxygen.
3. Heat and mass transfer coefficients are not well characterised for a burning carbon particle.
4. The floating and sinking of particles in a fluidised bed are under investigation.
5. The sequestration of CO₂ by solid CaO etc.
6. The gasification of wastes in fluidised beds.
7. Events inside a fluidised bed are being imaged using magnetic resonance techniques (also with Prof L.F.Gladden).

Modelling of oscillating reactions and natural convection (with Dr Cardoso)
The reaction P -> A -> B has been modelled as occurring in a fluid inside a spherical vessel where natural convection is driven by the heat released by the second chemical step. The work is related to the behaviour of cool flames, where strong oscillations are displayed.

Selected Publications:

C.J. Butler, A.N. Hayhurst and E.J.W. Wynn, “The size and shape of silica particles produced in flames of H₂ + O₂ + N₂ with a silicon-containing additive” Proceedings of The Combustion Institute, 2002, 29, 1047 - 1054.

A.N. Hayhurst and S.G. Taylor, “The stabilities of the gas-phase ions Li⁺.H₂O, Li⁺.(H₂O)₂ and Li⁺.CO as measured by mass-spectrometric sampling of fuel-rich flames of C₂H₂ + O₂”, Phys. Chem Chem. Phys., 2003, 5, 1610 – 1618.

A.P. Collier, A.N. Hayhurst, J.L. Richardson and S.A. Scott, “The heat transfer coefficient between a particle and a bed (packed or fluidised) of much larger particles”, Chemical Engineering Science, 2004, 59, 4613 – 4620.

J-S Chern and A.N. Hayhurst, “Does a large coal particle in a hot fluidised bed lose its volatile content according to the shrinking core model ?”, Combustion and Flame, 2004, 139, 208 – 221.

A.N. Campbell, S.S.S. Cardoso and A.N. Hayhurst, "The influence of natural convection on the temporal development of the temperature and concentration fields for Sal'nikov's reaction, P -> A -> B, occurring batchwise in the gas phase in a closed vessel", Chemical Engineering Science, 2005, 60, 5705 - 5717.

Publications list, 1962 - 2008

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