On-line monitoring of the fouling of the boiler heating surfaces

Abstract

The designed system for the monitoring of the fouling of the furnace and super-heaters/reheaters, presented in the paper, will make it possible to operate the boiler with high efficiency. Measurements of temperatures, pressures, flows, and gas analysis data are used to perform heat transfer analysis in the boiler furnace and evaporator. Power boiler efficiency is calculated by an indirect method. The local and average degree of the combustion chamber slagging is determined in an "on-line" mode. In the case of superheaters, the fouling coefficient is determined for each superheater stage, due to big differences in ash-related fouling of individual stages. Fouling processes deteriorate the boiler capacity and efficiency and increase the rate of corrosion of the boiler heating surfaces. The energy consumption of flue gas fans rises as well because the accumulation of slag and ash involves higher pressure losses at individual superheater stages. In addition, examples of ash fouling of individual boiler heating surfaces are presented and discussed in the paper.