加压流化床煤富氧燃烧的CO2生成特性研究

Study on CO2 Generation Characteristics of Oxy-fuel Coal Combustion in Pressurized Fluidized Bed

在30 kWth加压流化床富氧燃烧小试实验台上,对榆林无烟煤及内蒙古褐煤开展了一系列加压流化床富氧燃烧实验。研究了燃烧压力、氧浓度和过量氧气系数对CO2生成特性的影响规律。实验结果表明:O2/CO2气氛的氧浓度提高到30%时,加压流化床富氧燃烧小试实验台烟气中的CO2浓度超过95%。随着燃烧压力的增加,空气气氛和30%O2/70%CO2气氛下的CO2生成率基本呈线性递增,而空气气氛下CO2生成率的递增速率比30%O2/70%CO2气氛高。加压对榆林无烟煤CO2生成率的提高比内蒙古褐煤更加显著。当O2/CO2气氛的氧浓度在25%~30%范围内时,其CO2生成率与空气气氛下的CO2生成率相近。相同燃烧压力条件下,CO2生成率随着过量氧气系数的增加而增大,但是增幅逐渐变小。过量氧气系数1.11~1.5范围内,燃烧压力越高,过量氧气系数对CO2生成率的影响越小.

Oxy-fuel combustion experiment of Inner Mongolia lignite and Yulin anthracite was conducted in a 30 kWth pressurized oxy-fuel fluidized bed.The effects of combustion pressure,combustion atmosphere and excess oxygen coefficient on the CO2 formation characteristics.The results show that:when the oxygen concentration in the O2/CO2 atmosphere is increased to 30%,the CO2 concentration in flue gas of the pressurized fluidized bed exceeds 95%.With the increase of combustion pressure,the CO2 generation rate in air atmosphere and 30%O2/70% CO2 atmosphere both increases linearly,while the CO2 generation rate in air atmosphere increases faster than that in 30%O2/70%CO2 atmosphere.Compared with Mongolia brown,the pressure effect on the CO2 generation rate of Inner Yulin anthracite coal is more significant. When the CO2 generation rate in the O2/CO2 atmosphere is similar to the CO2 generation rate in the air atmosphere,the oxygen concentration in it is between 25% and 30%.Under the same combustion pressure,the CO2 generation rate increases with the increase of the stoichiometric air coefficient,but the increase rate is gradually smaller.When the stoichiometric air coefficient is in the range of 1.11 to 1.5,the positive effect of increasing stoichiometric air coefficient on the CO2 generation rate is more obvious with a lower combustion pressure.