No abstract

The article deals with the problem of optimizing the operation of soot blowers in a pulverized coal-fired boiler based on the instantaneous degree of cleanliness of heating surfaces, determined in real time. The elaborated methodology of calculations and the algorithm that determines the optimal configuration of the blowers operation has been implemented and tested on a boiler with a capacity of 380 t/h. The indicator defining the degree of cleanliness of a given heating surface is calculated using available measurements of process parameters based on the epsilon-NTU method. The calculations are carried out in the DCS system for each surface individually (air and water heaters, evaporator, superheaters). During the standard operation of the boiler, the adopted methodology was verified, having analysed the usefulness of the tool to assess the boiler cleanliness under operating condition.

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Nitrogen dioxide is one of the most dangerous air pollutants, because its high concentration in air can be directly harmful to human health. It is also responsible for photochemical smog and acid rains. One of the most commonly used techniques to tackle this problem in large combustion plants is selective catalytic reduction (SCR). Commercial SCR installations are often equipped with a V2O5−WO3/TiO2 catalyst. In power plants which utilize a solid fuel boiler, catalysts are exposed to unfavorable conditions. In the paper, factors responsible for deactivation of such a catalyst are comprehensively reviewed where different types of deactivation mechanism, like mechanical, chemical or thermal mechanisms, are separately described. The paper presents the impact of sulfur trioxide and ammonia slip on the catalyst deactivation as well as the problem of ammonium bisulfate formation. The latter is one of the crucial factors influencing the loss of catalytic activity. The majority of issues with fast catalyst deactivation occur when the catalyst work in off-design conditions, in particular in too high or too low temperatures.