Standard Article

15 Ash Fouling of Boiler Tubes and Thermophysical Properties of Deposits

Part 4. Solid Fuels

  1. Arvo Ots

Published Online: 15 JUL 2010

DOI: 10.1002/9783527628148.hoc069

Handbook of Combustion

Handbook of Combustion

How to Cite

Ots, A. 2010. Ash Fouling of Boiler Tubes and Thermophysical Properties of Deposits. Handbook of Combustion. 4:15:533–555.

Author Information

  1. Tallinn University of Technology, Thermal Engineering Department, Tallinn, Estonia

Publication History

  1. Published Online: 15 JUL 2010


A brief overview is presented of ash fouling of heat transfer surfaces of boiler and the thermophysical properties of deposits. Loose and bound ash deposit formation on transverse-flow boiler tubes is treated. Composition of the bound deposits differs from the composition of fly ash passing through the heat transfer surface. Ash deposited on boiler tubes is examined as a porous material with the effective thermal conductivity. At higher temperatures, heat exchange in a porous body also becomes affected by radiant heat transfer inside the material. The radiation properties of ash deposits are also discussed. The radiation flux originating from the ash particle layer and deposit layer is spectral in the region of short wavelengths but for a smooth slag layer the selectivity is negligible.


  • ash fouling;
  • ash particle layer;
  • boiler tubes;
  • deposits;
  • radiant heat transfer;
  • thermophysical properties