【摘要】 在900℃固定床热解装置中,考察了诸多因素(水分、挥发分、热应力、热解时间以及介质氛围)对粒径为0．61～6．0mm的粉煤颗粒的颗粒大小的影响．结果表明,低挥发分福建无烟粉煤的热解过程仅发生一次碎裂,热解过程中煤粒大小的变化在1 min内即可完成,热应力对煤颗粒大小变化起主要作用,有5%～20%的煤颗粒爆裂为更小的颗粒,而水分与挥发分的挥发对煤粒大小变化的影响不明显；煤样高湿含量(15%)时对大煤粒(＞2．5 mm)在热解过程中粒径大小的变化有一定影响,但对小煤粒(＜1．6mm)几乎没有影响；热解过程中介质氛围对煤粒变化的影响很大,水蒸气对煤粒大小变化的影响要比空气大,而混合气介质(空气/水蒸气)介于这两者之间．更多还原

【Abstract】 The study on the size variation of coal particles has significance for the reaction results and process simulations of coal pyrolysis and gasification.The influencing factors,such as the moisture,volatile,pyrolysis time,medium atmos- phere and heat stress effect,on the size variation (0.61—6.0 mm) of low volatile Fujian coal particles,were investigated in a fixed bed under the pyrolysis temperature 900℃.The results indicate that the heat stress,resulting from the tempera- ture difference between coal inner and its outer surface,is a dominate influencing factor on the size variation of coal parti- cles in the pyrolysis process.However,the evaporation of moisture and volatilization of volatile in coal exhibit little influ- ence.The size variation of coal particles can be completed in just 1 minute during pyrolysis and about 5%—20% coal parti- cles will break into smaller particles in pyrolysis process.For the original coal with larger size (＞2.5mm),the coal size in pyrolysis reduces obviously when the moisture of coal reaches up to 15%,but for the original coal with smaller size (＜1.6 mm) the coal size in pyrolysis does not change at different moistures.It also shows that the medium atmosphere in pyrolysis has a stronger effect on the size variation of coal particles.The stream in coal gasification can cause more frag- ments in the coal particles and reduce their size more than that of the air in Combustion.更多还原