Flammability characterizacion of biomass and coal mixtures

Abstract

The use of renewable energy has heavily increased in the last years due to climate change and global warning. Because of that, several countries have reduced the use of coal to produce energy, leading to abandon or disuse of multiple power plants. In this context, it is possible to adapt the power plant to use a mixture of coal and biomass as fuel in order to reduce coal consumption while keeping in operation these plants. In this context it is necessary to define the flammability parameters of the fuel mixture, in order to define possible new protection and prevention measures. The present study focuses on the flammability characterization of a coal and wheat straw mixture (80% and 20% respectively) through two tests: minimum ignition energy (MIE) and minimum ignition temperature of cloud (MITc). These tests were also performed in the raw coal and wheat straw in order to define how the mixture of both fuels might influence flammability parameters. From the results it was found that the mixture significantly reduced the MIE if compared to both materials, as the mixture presented a MIE of 170 mJ, while coal and straw 540 mJ and >1000 mJ respectively. On the other hand, MITc of the mixture was slightly increased if compared to straw (500ºC versus 480ºC) but decreased if compared to coal (640ºC). These results show the importance of analysing the flammability and explosion severity parameters of biomass and coal mixtures, as both materials influence each other, and equipment and facilities should be designed in accordance to the used fuel.