A Numerical Model for Predicting Biomass Particle Depositions in a PF Furnace

Using biomass as a fuel stock in pf furnaces has been recognized as an important measure that is taken in order to reduce emissions in the power generation industry. However, firing biomass presents a number of technical problems, that substantially limit its use in existing coal-fired plants and the formation of deposits in the system is one of the key issues. This paper presents a computational fluid dynamics model that predicts biomass particle depositions in an industrial pf combustion test furnace where the release of potassium in the biomass has been modeled and the residual ash composition determines the stickiness of the particle. The direct impact of the particles on the deposition surface has been considered as the dominant pathway of the particle deposition in the furnace and the overall deposition rate is determined by the chemical and kinetic states of the particles when they come in contact with the deposition surface. When the combustion products leave the furnace then undergo cooling in the boiler section. The processes that take place are discussed, and the information is given on the deposition of the potassium species. A number of simulations have been performed and the model predictions have been compared with the limited available experimental data. The effects of the various model constants on the formation of the deposition have been discussed.