水蒸气对煤焦恒温下燃烧特性的影响

Effects of Water Vapor on the Isothermal Combustion Characteristics of Coal Char

利用自制的恒温热重测量实验台,研究了水蒸气对煤焦燃烧特性的影响规律。结果表明:在低氧浓度下,水蒸气对煤焦燃烧影响显著,使燃烧失重速率增大,燃尽时刻提前,影响程度随氧气浓度的增加而减弱,主要是由于在低氧浓度下,水蒸气与煤焦发生了气化反应,并且反应随着氧浓度的增加而减弱;反应温度越高,水蒸气对煤焦燃烧特性影响越显著;气氛中存在二氧化碳,水蒸气仍能改善煤焦的燃烧特性;原煤煤化程度越高,水蒸气对煤焦燃烧特性的影响越小,即水蒸气对反应活性高的煤焦燃烧影响明显。

Effects of water vapor on the combustion characteristics of coal char were studied on the isothermal thermo-gravimetric measurement bench. The results show that under low oxygen concentration, water vapor affects the coal char combustion significantly, which noticeably increases the weight loss rate and reduces the burning time. Since the gasification reaction of water vapor and coal char happens and becomes weaker under the condition of more oxygen, the influence decreases with the increase of oxygen concentration. Moreover, the effects of water vapor on the combustion characteristics of coal char keep increasing with the rise of reaction temperature. Water vapor can improve the combustion characteristics of coal char even though carbon dioxide exists. Additionally, the effects of water vapor on the combustion characteristics of coal char reduce with coalification degree getting higher, in other words, water vapor can obviously affect combustion characteristics of the coal char with high reactivity.