关键词: 紫椴, 氧浓度, 可控气氛锥形量热仪, 发烟性能

Abstract:

Smoke is the general term of the substance threw off from a burning material, the mixture of tiny solid particles, tiny fluid drops and gaseous compounds. In this paper, a controlled-atmosphere cone calorimeter was used to investigate the smoking property of wood (Tilia amurensis) treated with fire-retardant monoammonium phosphate(MAP) and the untreated for comparison. The samples were tested at a heat flux of 50 kW·m^-2 and controlled atmosphere of oxygen concentration 15%～21%. The releasing of dense smoke and poisonous gases (mainly carbon monoxide) of the sample burnt under different oxygen concentration were summarized by comprehensive analysis of the smoke related parameters such as rate of smoke release(RSR), total smoke release(TSR), specific extinction area(SEA), carbon monoxide production rate (P_CO) and yield of carbon monoxide (Y_CO). The results indicated that the dense smoke release (RSR, TSR and SEA) was much higher in flaming than in after-glowing. When oxygen concentration was about 16%, the smoke release(RSR、TSR and SEA) of MAP treated wood was similar to the untreated. When the wood specimens burned in the same oxygen concentration, MAP treated wood gave a lower dense smoke release (RSR、TSR and SEA) than the untreated if the oxygen concentration was higher than 16%. On the contrary, if the oxygen concentration was lower than 16%, the smoke release(RSR、TSR and SEA) of MAP treated wood was higher than the untreated. In the experimental oxygen concentration range, the CO release (P_CO and Y_CO) of MAP treated wood was higher than the untreated wood. With the increase of oxygen concentration, the smoke release (RSR, TSR and SEA) and CO release (P_COand Y_CO) of MAP treated wood decreased; the smoke release (RSR、TSR and SEA) and CO production rate (P_CO ) of the untreated wood increased due to the oxygen shortage of the system caused by the violent combustion, while CO yield (Y_CO) decreased because of comparatively more complete combustion at certain weight loss of the wood. It was concluded that the smoke release including CO formation of burning MAP treated wood tend to increase with the decrease of oxygen concentration in the air.

Key words: Tilia amurensis, oxygen concentration, controlled_atmosphere cone calorimeter, smoking property