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CFD modelling of the fast pyrolysis of biomass in fluidised bed reactors: Modelling the impact of biomass shrinkage

By Konstantinos Papadikis, S. Gu and A.V. Bridgwater

Abstract

The fluid–particle interaction and the impact of shrinkage on pyrolysis of biomass inside a 150 g/h fluidised bed reactor is modelled. Two 500 m in diameter biomass particles are injected into the fluidised bed with different shrinkage conditions. The two different conditions consist of (1) shrinkage equal to the volume left by the solid devolatilization, and (2) shrinkage parameters equal to approximately half of particle volume. The effect of shrinkage is analysed in terms of heat and momentum transfer as well as product yields, pyrolysis time and particle size considering spherical geometries. The Eulerian approach is used to model the bubbling behaviour of the sand, which is treated as a continuum. Heat transfer from the bubbling bed to the discrete biomass particle, as well as biomass reaction kinetics are modelled according to the literature. The particle motion inside the reactor is computed using drag laws, dependent on the local volume fraction of each phase. FLUENT 6.2 has been used as the modelling framework of the simulations with the whole pyrolysis model incorporated in the form of user defined function (UDF).<br/><br/

Year: 2009
OAI identifier: oai:eprints.soton.ac.uk:149223
Provided by: e-Prints Soton

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Citations

  1. (2003). A Eulerian–Lagrangian model to simulate two-phase/particulate flows, Centre for Turbulence Research, Annual Research Briefs,
  2. (1988). A kinetic model for the production of liquids from the flash pyrolysis of biomass, doi
  3. (1986). A new model for thermal volatilizationofsolidparticlesundergoingfastpyrolysis,ChemicalEngineering doi
  4. (2007). A.S.Chaurasia,B.D.Kulkarni,Mostsensitiveparametersinpyrolysisofshrinking biomass particle, doi
  5. (1993). Analysis of convection and secondary reaction effect effects within porous solid fuels undergoing pyrolysis, doi
  6. (2004). Bubbly Flows: Analysis, Modelling and Calculation, doi
  7. (2009). CFD modelling of the fast pyrolysis of an in-flight cellulosic particle subjected to convective heat transfer, doi
  8. (2008). CFD modelling of the fast pyrolysis of biomass in fluidised bed reactors. Part A: Eulerian computation of momentum transport in bubbling fluidised beds, doi
  9. CFD modelling of the fast pyrolysis of biomass in fluidised bed reactors. Part B: heat, momentum and mass transport inbubblingfluidisedbeds,ChemicalEngineeringScience64(2009)1036–1045. doi
  10. (1998). Comparison of semi-global mechanisms for primary pyrolysis of lignocellulosic fuels, doi
  11. (2002). Discrete particle-continuum fluid modelling of gas–solid fluidised beds, doi
  12. (1999). Eulerian computation of heat transfer in fluidized beds, doi
  13. (1997). Eulerian simulation of bubble formation at a jet in a two-dimensional fluidized beds, doi
  14. (1952). Evaporation from drops. Part I,
  15. (1975). Fluid-bed Heat Transfer,
  16. (1983). Fundamentals of Fluidised-bed Chemical Processes, doi
  17. (1976). Heat Transfer to Horizontal Tubes in Shallow Fluidized Beds. ASMEpaper 76-HT-67,
  18. (1996). Heat, momentum and mass transport through a shrinking biomass particle exposed to thermal radiation, doi
  19. (1961). Integrable form of droplet drag coefficient,
  20. (1979). Local drag laws in dispersed two-phase flow, NUREG/CR1230, ANL-79–105,
  21. (1985). Modelling and experimental verification of physicalandchemicalprocessesduringpyrolysisoflargebiomassparticle,Fuel 64 doi
  22. (2006). Modelling of large-scale dense gas–solid bubbling fluidised beds using a novel discrete bubble model, doi
  23. (1991). Modelling of the pyrolysis of biomass particles. Studies on kinetics, thermal and heat transfer effects, doi
  24. (2005). Multiphase Flow Dynamics 2, Thermal and Mechanical Interactions, doi
  25. (1998). Multiphase Flows with Droplets and Particles, doi
  26. (1992). Numerical calculation of wallto-bed heat-transfer coefficients in gas-fluidized beds, doi
  27. (2000). Numerical prediction of heat transfer in fluidized beds by a kinetic theory of granular flows, doi
  28. (1999). Principles and practice of biomass fast pyrolysis processes for liquids, doi
  29. (1978). Relative motion and interfacial drag coefficient in dispersed two-phase flows of bubbles, drops and particles,
  30. (1988). Single-particle pyrolysis: correlations of reaction products with process conditions, doi
  31. (1998). Struggle with computational bubble dynamics, in: doi
  32. (2004). The heat transfer coeffi-cientbetweenaparticleandabed(packedorfluidised)ofmuchlargerparticles,
  33. (2002). The heat transfer coefficient for a freely moving sphere in a bubbling fluidised bed, doi
  34. (1970). The motion of particles in turbulent gas streams, in: doi
  35. (1991). Transport phenomena in multi-particle systems-IV. Heat transfer to a large freely moving particle in gas fluidized bed of smaller particles, doi
  36. (1973). Types of Gas Fluidization, doi
  37. (1933). Uber die grundlegenden Berechungen bei der Schwerkraftaufbereitung,

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