The potential fire and explosion hazards in biomass co-firing with conventional fossil fuels based on data obtained during testing

The use of biomass, in particular in power engineering, has created new hazards for mankind and for the environment; including fire and explosion hazards. A description was provided of the use of biomass in power engineering in existing boilers fired by hard coal [1- 10]. Literature and experimental values were outlined for selected parameters of ignitability and explosiveness of selected biomass parameters, and a comparison was presented of the ignitability and the explosiveness parameters for selected biomass dust, a mixture of coal and biomass and for coal dust (according to PN-EN 14034, PN-EN 50281-2-1:2002 and PN-EN 13821:2004). Based on an analysis of the obtained results, it was ascertained that performing analyses of explosive parameters separately, or with a share of coal and biomass, is an incorrect practice due to the fact that in literature on this subject or in the databases of Internet sources, the quoted values are purely indicative in nature and may differ from the conditions actually prevailing in the given technological process during biomass co-firing. A review of the value of the Kst explosiveness factor showed that dust of biomass mixtures may be categorised to dust with strong explosiveness parameters, and their value is higher than coal dust which is comprised within them. Consequently the testing of post-filtering dust is clearly justified