Analysis and monitoring of the combustion performance in a biomass power plant

Abstract

Combustion air systems are an important aspect of the industrial boiler's performance, and they are being used increasingly to reduce emissions. Generally, improvements in boiler performance and emissions reduction can be achieved by modifying the air system. In the specific case of primary air, its temperature, distribution, and vibration of the grate significantly affect the conversion and mixing of biomass. Consequently, in this work, a comprehensive analysis of a biomass power plant operation, which is a result of an experimental campaign developed for 12 days is presented. In this regard, since the fuel has highly variable physical and chemical properties, disturbances causing an unsteady conversion process and corrosion risks were verified. Furthermore, the influence of the primary air distribution and the grate vibration cycles was evaluated through different tests. The grate vibration periods revealed that increasing the interval without vibrations results in a significant reduction of CO emissions. However, increasing this period may lead to some agglomeration problems in the grate. Concerning the primary air supply, in the three different sections of the grate, the supply of a more significant amount of air in the first two sections of the grate, in the central region of the grate, decreases the CO emissions. Additionally, the possibility to reduce the flue gas temperature using empirical correlations for a quick estimation of acid dew point during flue gas cooling for heat recovery to preheat the primary air was studied. The results revealed a large amount of energy that can be recovered without low-temperature corrosion problems, and 7% of the total input energy can be saved.