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13 Agglomeration in Fluidized Bed Combustion: Mechanisms, Detection, and Counteraction

Part 4. Solid Fuels

  1. J. Ruud van Ommen1,
  2. Weigang Lin2

Published Online: 15 JUL 2010

DOI: 10.1002/9783527628148.hoc067

Handbook of Combustion

Handbook of Combustion

How to Cite

van Ommen, J. R. and Lin, W. 2010. Agglomeration in Fluidized Bed Combustion: Mechanisms, Detection, and Counteraction. Handbook of Combustion. 4:13:471–491.

Author Information

  1. 1

    Delft University of Technology, Department of Chemical Engineering, Delft, BL, The Netherlands

  2. 2

    Technical University of Denmark, Department of Chemical and Biochemical Engineering, Lyngby, Denmark

Publication History

  1. Published Online: 15 JUL 2010

Abstract

Agglomeration of bed material is a major operational problem in fluidized bed combustion, especially when using biofuels. The main mechanism of agglomeration involves the formation of low melting point compounds, which results in increased particle stickiness and formation of agglomerates. The presence of alkali components from the biofuels leads to reactions with silica from the bed material, forming alkali silicates that have a melting point below the typical operating temperatures of about 850 °C. In addition, hydrodynamics and particle interaction mechanisms will play a role. If no counteraction is taken, severe agglomeration can eventually result in defluidization of the bed and subsequent shut-down of the installation. Therefore, an early warning system to reliably detect agglomeration is of high importance. Such a system typically consists of the measurement of operating variables such as pressure coupled with analysis of these data. Different methods proposed in the literature are reviewed in this chapter. As soon as agglomeration has been detected, appropriate counteractions should be taken, such as changing the operating conditions or using additives. Alternatively, different bed materials can be used or the fluidized bed design may be adapted to become less susceptible to agglomeration.

Keywords:

  • agglomeration;
  • biofuels;
  • fluidized bed;
  • hydrodynamics;
  • particle interaction;
  • process monitoring