摘要
讨论了煤燃烧过程中NO_x的析出特性和各种因素的影响。实验表明,加石灰石脱硫将使NO_x排放量上升,但是通过选择适当的运行参数,如温度、氧浓度、Ca/S比等和吸收剂种类,可以大大缓解脱硫与降低NO_x排放之间的矛盾。实验温区为600—1150℃,包括了流化床燃烧的温度范围,部分结果在流化床燃烧器上作了验证。
The characteristics of NOx formation in coal combustion and the effect of various factors were studied. The experiments were carried out at 600-1150℃, which covers the temperature range of fluidized bed combustion. The NOx of fuel origin is the dominant part of nitrogen oxides formed. It was shown that NOx formation is strongly dependent upon temperature. The effect of oxygen concentration in the combustion zone was also examined. The results show that the elemental oxygen required to form NOx of fuel origin comes from both the fuel itself and the combustion air. This role of fuel oxygen will make oxygen-lean combustion less effective for lowering the NOx emission. The influence of limestone desulphurization was also studided. It was found that the dynamics of NOx formation is changed by the addition of the sorbent. The course of NOx formation will last a longer time period and the time at which maximum NOx concentration is reached will be considerably delayed in comparison with the limestone-free case. NOx emission is increased due to possible catalytic effect of the mineral impurities in the limestone used. However, when limestone was pre-calcinated no remarkable increase in NOx formation was found. This is explained by assuming that calcination will change the particle struture of the sorbent. Consequently, properly selecting sorbent type and some operation parameters will be crucial to the simultaneous control of NOx and SO_2 (?)mission.
出处
《燃料化学学报》
EI
CAS
CSCD
北大核心
1991年第1期71-76,共6页
Journal of Fuel Chemistry and Technology
关键词
煤
燃烧
石灰石
脱硫
氮氧化物
fuel-NOx
desulphurization
formation dynamies
