INFLUENCE OF POLLUTION ON THE HEAT EFFICIENCY OF HEATING SURFACES WITH USING WATER-FUEL EMULSION BASED ON LOW-VISCOSITY FUELS

Abstract

When burning water-fuel emulsions with a water content of 30% due to decrease in the rate of low-temperature sulfuric acid corrosion to an acceptable level of 0.25 mm/year, condensation heating surface can be installed in the exhaust gas boilers. On the basis of studies and literature data, the values of the bulk density of pollutions in the burning of low-viscosity fuels and water-fuel emulsions based on them were adopted. Relations of the pollution layer thickness on the wall temperature on the basis of the available experimental data on the intensity of pollution at different values of the wall temperature, the literature data, and the calculated values of the bulk density of the pollution layer are obtained. The variable nature of the relations indicates the need to determine the values of the pollution thickness for each appropriate range of wall temperature values. Based on the obtained relations of the mean thickness of the pollutions on the wall temperature, as well as the values of the coefficient of equivalent thermal conductivity, the relations of the pollution coefficients on the wall temperature are constructed. The obtained relations show that at the same wall temperatures during the combustion of water-fuel emulsions with a water content of 30% the value of the pollution coefficients is significantly lower than when burning the non-watered fuel. Comparison of the values of the pollution factor confirms the reliability of the studies of pollution processes and analytically determined values carried out in the experimental setup. The relations of the heat transfer coefficient of the polluted surface at the heating surface temperatures in the range of 70-210 °С for the combustion of low-viscosity fuels and water-fuel emulsions based on them were proposed. It is expediently to evaluate the effect of impurities on the values of thermal efficiency, because they allow to reveal the overall effect on the value of the pollution coefficient and the unevenness of their blowing. The obtained relations of the pollution coefficients, heat transfer and thermal efficiency in the design of convective heating surfaces for exhaust gas boilers are proposed

Keywords

• утилизационный котел
• поверхность нагрева
• загрязнения
• водотопливная эмульсия
• маловязкое топливо