Influence of heating surfaces pollution on the heat transfer intensity in exhaust gas boilers at water-fuel emulsion combustion

The heating surfaces pollution layer thickness versus the wall temperature during the 1000-hour flow influence at combustion of fuel-oil and water-fuel emulsions have been obtained. The heat conductivity research for various pollution conditions on the heating surfaces with regard to the accepted pollution structure were carried out. The obtained dependences show that the value of equivalent heat conductivity factor of pollution depends on the porosity, form and size of the particles in the layer composition and properties of the medium that fills the voids between the particles at the appropriate wall temperature. The results of experimental and rated pollution factors, heat transfer and thermal efficiency at combustion water-fuel emulsion for dry and condensing heating surfaces of exhaust gas boilers at wall temperatures over the range 70 to 210°C are presented. Analysis of the research re-sults shows that the combustion of water-fuel emulsions with water content of 30% reduces the layer of heating surfaces pollution and increases the value of heat transfer factor and thermal efficiency. The reliability of the obtained results with published statistical data for the burning standard fuels was verified. The obtained values of factors can be used both in the design and operation of condensing heat-ing surfaces