Possibility analysis of combustion of torrefied biomass in 140 t/h PC boiler

Division of Boilers and Steam Generators, Silesian University of Technology, Konarskiego 20, 44-100 Gliwice, Poland

^a Corresponding author: katarzyna.jagodzinska@polsl.pl

Abstract

The study attempts to evaluate the impact of combustion of torrefied willow (Latin: Salix viminalis) and palm kernel shell (Latin: Elaeis guineensis) on the heat exchange in a 140 t/h PC boiler through an analysis of 6 cases for different boiler loads (60 %, 75 % and 100 %) and a comparison with coal combustion. The analysis is premised on a 0-dimensional model based on the method presented in [15, 16, 17] and long-standing experimental measurements. Inter alia, the following results are presented: the temperature distribution of flue gases and the working medium (water/steam) in characteristic points of the boiler as well as heat transfer coefficients for each element thereof. The temperature distribution of both fluids and the heat transfer coefficients are similar for all analysed fuels for each boiler load. However, the flue gas temperature at the outlet is higher in the case of torrefied biomass combustion. Due to that, there is an increase in the stack loss, which involves a decrease in the boiler efficiency. The conclusion is that torrefied biomass combustion is possible in a PC boiler without the need to change the boiler construction. However, it would be less effective than coal combustion.