Analysis of dust explosion hazards and risk assessment of dust from biomass fuel: Wood pellets

Wood pellets, widely adopted as renewable fuel in residential and industrial biomass power generation, pose significant dust explosion hazards due to their inherent physical properties. This study presents a combined experimental and a combined experimental and semi-quantitative risk assessment matrix approach to assess explosion risks associated with biomass dust, focusing on wood pellets. Key explosion parameters, including Minimum Ignition Energy (MIE), Minimum Explosible Concentration (MEC), maximum explosion pressure ( P max ), and maximum deflagration index ( K max ), were measured to characterize explosion behavior of wood-pellet dust. The influence of particle size was systematically analyzed, revealing a monotonic increase in MIE, while MEC exhibited a U-shaped trend, reaching a minimum at intermediate sizes. K max and P max increase with decreasing size, suggesting more severe explosion consequences. The method of comminution significantly affected explosibility: dust produced via cutting showed lower sensitivity and ignition propensity than that generated by crushing under equivalent size distributions. To support risk assessment, a two-dimensional matrix was introduced using explosion severity and ignition sensitivity parameters. Results show that wood pellet dust poses a high explosion risk. This study offers practical insights to identify and mitigate dust explosion hazards associated with the handling and use of wood pellets in biomass energy systems.