【目的】准格尔煤燃烧后灰渣中Al2O3含量超过45%,具有重要的资源综合利用价值。为解决传统循环流化床锅炉燃用准格尔煤时飞灰活性差、Al2O3提取效率低等问题,提出采用水煤浆循环流化床燃烧方式改善灰渣特性。【方法】利用3MW循环流化床燃烧试验台研究了给料方式、运行氧量、床温、一次风率等对飞灰可燃物含量的影响,并利用比表面积及孔径测定仪、扫描电镜、X射线荧光光谱仪,X射线衍射仪等对不同粒径飞灰成分和微观形貌进行分析。【结果】结果表明:随着床温、运行氧量、一次风率的增加,飞灰可燃物含量逐渐减小;水煤浆粒化燃烧的飞灰可燃物含量明显低于未粒化。飞灰中可燃物主要存在于40μm以下颗粒,随着飞灰粒径的减小,可燃物含量逐渐增加;小颗粒飞灰大部分是由孔隙结构不发达的颗粒构成,可燃物含量较高;随着飞灰粒径的增大,飞灰比表面积和总孔容逐渐减小,平均孔径逐渐增大,粒化末煤浆的总孔容和平均孔径要小于精煤浆;对灰样进行成分分析,发现随着粒径的减小,Al2O3的含量逐渐增大,15μm以下粒径段飞灰中Al2O3的含量达到51.77%;对灰样进行物相检索和半定量分析,活性较好的γ-Al2O3峰随着粒径的增大逐渐减弱,莫来石含量随着粒径的增大逐渐增加,使飞灰的提铝效率降低。总体来看,粒径小于50μm的飞灰中Al2O3的含量更高同时莫来石含量更少,更适合作为提铝工艺原料。

【Purposes】The content of Al O  in the fly ash and slag after combustion of Zhungeer  coal is over 45%, which has important value of comprehensive utilization of resources. In order to  solve the problems of poor fly ash activity and low Al O  extraction efficiency when using Zhungeer  coal in conventional circulating fluidized bed boilers, a coal water slurry circulating fluidized bed com‐ bustion method was proposed to improve the ash characteristics. 【Methods】 The effects of feed  mode, operating oxygen content, bed temperature, and primary air rate on unburned combustible in  fly ash were studied by using a 3 MW circulating fluidized bed combustion test facility, the composi‐ tion and micro-morphology of fly ash with different particle sizes were analyzed by using specific sur‐ face area and pore diameter analysis apparatus, scanning electron microscope, X-ray fluorescence  spetrometer, and X-ray diffractometer (XRD). 【Findings】 The results show that the unburned com‐ bustible content in fly ash decreases with the increase of bed temperature, operating oxygen content,  and primary air rate, and the unburned combustible content in fly ash in coal water slurry granulated  combustion is obviously lower than that in ungranulated combustion. The combustibles in fly ash are  mainly below 40 μm, and the unburned combustible content increases with the decrease of fly ash par‐ ticle size. Most of small fly ash particles were composed of undeveloped pore structure particles with  high combustible content. The BET specific surface area and total pore volume decrease with the in‐ crease of fly ash particle size, while the average pore size increases gradually, and the total pore vol‐ ume and the average pore size of the slack coal slurry are smaller than those of the clean coal slurry. It  can be found that the content of Al O  increases with the decrease of particle size, and the content of  Al O  in fly ash with particle size less than 15 μm is 51.77%. Acctording to the phase retrieval and  semi-quantitative analysis of ash samples, the γ -Al O  peak with higher activity is gradually weak‐ ened with the increase of particle size, the mullite content is gradually increased with the increase of  particle size, and the aluminum extraction efficiency of fly ash decreases. As a whole, in fly ash with  particle size less than 50 μm,the content of Al O  is higher and the content of mullite is lower, making  it more suitable to be used as raw material for aluminum extraction process.