Biomass explosion testing: Accounting for the post-test residue and implications on the results. (July 2015)

• Record Type: Journal Article
• Authors: Slatter, David J.F.; Sattar, Hamed; Medina, Clara Huéscar; Andrews, Gordon E.; Phylaktou, Herodotos N.; Gibbs, Bernard M.
• Is Part Of: Journal of loss prevention in the process industries. Volume 36(2015:Jul.)
• Page Start: 318
• Page End: 325
• Publication Date: 2015-07
• Subjects: Dust explosions -- Combustion residue -- Mass burnt; Chemical industries -- Safety measures -- Periodicals; 660.2804
• DOI: 10.1016/j.jlp.2015.02.015
• Languages: English
• ISSNs: 0950-4230

Abstract

Abstract: This work uses the ISO 1 m 3 dust explosion equipment to study the explosion properties and combustion characteristics of pulverized biomass dust clouds. An unreported feature of this apparatus is that in rich concentrations only about half the dust injected is burned in the explosion, while the overpressures remain high. This work was undertaken to try to understand the mechanisms of these phenomena, through the accounting of the debris at the end of the explosion, some of which was found in the form of impacted "cake" against the vessel wall. One possible explanation is that the residue material was biomass dust blown ahead of the flame by the explosion induced wind, impacted on the walls where then the flame side underwent flame impingement pyrolysis and the metal (wall) side material was compacted but largely chemically unchanged. The results also show that the heat transfer insulation provided by the powder wall layer contributes to the higher observed pressures. The risk of explosion with significant overpressures remains at 100% in very rich environments (equivalence ratios of up to 6) although these environments are leaner than thought due to material sequestration within the "cake". There was little indication that a rich combustion limit was approached, this was determined in standard testing equipment that has been modified and calibrated to handle larger quantities of powder than normal. Highlights: Residue post combustion is hardly different from original unburnt material. Pressure loss traces indicate that unburnt residue is hardly interacting with flame front. No rich limit for solid fuel dust explosions found in experiments or literature.