Influence of chemical composition of biomass on agglomeration process in fluidized bed of boiler E-75-3,9-440 DFT

Abstract

The combustion of biofuels in the fluidized bed is an attractive technology to process biomass. However, the technology of biomass combustion in fluidize beds is characterized by several problems associated with the agglomeration of bed material. The aim of the research is to study the influence of the chemical composition of biomass on the agglomeration process of the fluidized bed of the boiler unit E-75-3,9-440 DFT. The boiler burns a mixture of by-products of pulp and paper production to increase stability of the fluidized bed and the duration of boiler operation between periods of its deslagging. The study has tested two types of biomass burned in a mixture in a steam boiler unit E-75-3,9-440 DFT with a fluidized bed. The authors also have studied the samples of agglomerates, bed, and fly ash to find out more about the agglomeration process. The elemental composition of samples of bark-wood waste, sewage sludge, agglomerates and ash has been studied. Elements affecting the process of agglomeration of the fluidized bed have been identified. The results of the analysis have showed that essential ash- and slag-forming components in the sewage sludge are silicon, calcium, sulfur, and potassium, and in the bark wood waste the essential ash- and slag-forming components are calcium, potassium, and sodium. The main elements influencing the process of agglomeration of the fluidized bed are alkaline elements of potassium and sodium. The results obtained make it possible to predict the agglomeration of the fluidized bed, to select the fuel mixture in the proportion necessary to reduce the agglomeration process.