Study On The Combustion And Explosion Characteristics Of Biomass Pellet Fuel Dust

With the rapid development of economy and increasing demand for energy,biomass pellet fuel has become a substitute for fossil fuels such as coal and oil and is widely used in the power generation industry because of its cleanliness and high volatile content.However,there is a potential danger of dust explosion in the production process,which may lead to dust explosion accidents and pose a great threat to human life and property.At present,the main raw materials of biomass granular fuel are dalbergia cochinchinensis,pine sawdust and cupressus funebris,and biomass is mainly composed of cellulose,hemicellulose and lignin.Therefore,mastering the combustion and explosion characteristics of the main raw materials of biomass granular fuel and the influence of internal components of graduate materials on combustion and explosion can provide effective information to prevent and control dust explosion.In this paper,the experimental research method is used to identify the explosion risk of biomass dust,establish the internal relationship between the combustion and explosion characteristics of biomass dust,compare the experimental and prediction data of single and mixed components,and reveal the interaction of components during combustion and explosion.1.The combustion mass loss behavior of dalbergia cochinchinensis,pine sawdust and cupressus funebris at the temperature range of 30～600℃under the heating rate of 10,20and 30℃/min was measured by Thermogravimetric-Fourier transform infrared spectroscopy combined system.The combustion behavior of biomass dusts with increasing temperature were analyzed.The apparent activation energy was calculated based on Kissinger-Akahira-Sunose,Flynn-Wall-Ozawa and Friedman methods,which was found that the apparent activation energy of dalbergia cochinchinensis and cupressus funebris was significantly smaller than that of pine sawdust.The main gas products of the three biomass dusts during combustion were CO₂,CO,CH₃COOH,H₂O,etc.the release amount of gas products of dalbergia cochinchinensis was the most,that of pine sawdust was the least.The maximum peak temperature of cupressus funebris released main gas products CO₂and CO was the lowest.2.The explosion characteristics of the there biomass dusts:dalbergia cochinchinensis,pine sawdust and cupressus funebris were studied by using dust layer ignition temperature apparatus,Godbert-Greenwald furnace apparatus and 20 L spherical explosion vessel.Based on the explosion characteristic parameters such as the minimum ignition temperature of dust layer and the minimum ignition temperature of dust cloud,the minimum explosion concentration,the maximum explosion pressure and the maximum explosion pressure rise rate,the explosion hazard ranking of three biomass dusts was as follows:dalbergia cochinchinensis>cupressus funebris>pine sawdust.The mass loss,temperature range and apparent activation energy of three biomass dust in the rapid devolatilization stage have correspondence with the explosion risk,and the mass loss of biomass dust in the rapid devolatilization stage was one of the main factors affecting explosion risk.3.The combustion behavior and explosion parameters of cellulose,hemicellulose and lignin,the main components of biomass dust,and their mixed dusts were determined by thermogravimetric analyzer and 20 L spherical explosion vessel.The results of comparative analysis and prediction showed that the increase of cellulose ratio increased the maximum mass loss peak strength and explosion pressure,and the increase of hemicellulose ratio increased the shoulder peak strength and explosion pressure,while the increase of lignin ratio resulted in the increase of solid residue and the decrease of explosion pressure.The interaction between the three components resulted in the experimental thermogravimetric curve of the mixed dust slightly lagging behind the predicted curve.The explosion pressure of the mixed dust is mainly determined by the promotion and inhibition of cellulose and lignin,while the rising rate of the explosive pressure is mainly affected by the content of hemicellulose.