高碱煤掺烧低钠煤的混煤结渣特性试验研究  

Experimental Study on Slagging Characteristics of High Alkali Coal Blended with Low Sodium Coal

作　　者：向家涛 桂其林 杨奕彬 李建峰 张世红[1] XIANG Jiatao;GUI Qilin;YANG Yibin;Li Jianfeng;ZHANG Shihong(State Key Laboratory of Coal Combustion,School of Energy and Power Engineering,Huazhong University of Science and Technology,Wuhan 430074,China;Baosteel Zhanjiang Iron&Steel Co.,Ltd.,Zhanjiang 524000,China)

机构地区：[1]华中科技大学能源与动力工程学院煤燃烧国家重点实验室,湖北武汉430074 [2]宝钢湛江钢铁有限公司,广东湛江524000

出　　处：《锅炉技术》2024年第6期42-50,共9页Boiler Technology

基　　金：湛江钢铁科研项目(K22ZGBG013)。

摘　　要：针对湛江钢铁发电单元锅炉在燃烧高碱煤时容易发生受热面沾污结渣的问题,提出了掺烧低钠煤的缓解措施。为了优化配煤掺烧方案,首先分别对高碱煤和低钠煤的煤质特性和燃烧特性进行分析,然后基于“沉降炉沉积炉”系统开展混煤燃烧试验,并采用煤灰成分评价指标预测不同掺烧比例下的混煤结渣特性。结果表明:高碱煤具有高挥发分、低灰分、高发热量及高碱金属含量的特点,具有良好的着火和燃尽性能,但结渣倾向较强。依据煤灰熔融温度判别煤种结渣倾向的评价指标参考价值比较有限,而基于煤灰成分预测煤种结渣倾向的指标中,煤灰钠当量综合考虑了煤种的灰分和煤灰碱金属含量,比碱酸比、硅铝比和铁钙比的预测结果更符合实际情况。通过与低钠煤进行掺混燃烧,能够有效降低高碱煤的结渣倾向,随着低钠煤的掺混比例增大,缓解结渣倾向的效果越明显。当掺烧质量分数75%的DN2或DN3时,混煤的结渣倾向已经低于单独燃烧DN4,进而可以解决单独燃用高碱煤时容易结渣的问题。Aiming at the problem that the boiler of Zhanjiang steel power generation unit is prone to fouling and slagging on the heating surface when burning high alkali coal,a mitigation measure by blending low sodium coal was proposed.In order to optimize the coal blending and burning scheme,the coal quality and combustion characteristics of high alkali coal and low sodium coal were analyzed firstly,and then the blended coal combustion experiment was carried out based on the“settling furnace-depositing furnace”system,and the coal ash composition index was used to predict the slagging characteristics of blended coal under different ratios.The results show that high alkali coal has the characteristics of high volatile,low ash,high calorific value and high alkali metal content.It has good ignition and burnout performance,but strong slagging tendency.The reference value of the evaluation index of coal slagging tendency according to the melting temperature of coal ash is limited.In the index of predicting slagging tendency of coal species based on coal ash composition,the sodium equivalent of coal ash comprehensively considers ash content and alkali metal content of coal species,which is more consistent with the actual situation than the prediction results of alkali acid ratio,silicon aluminum ratio and iron calcium ratio.The slagging tendency of high alkali coal can be effectively reduced by blending combustion with low sodium coal.The effect of slagging tendency is more obvious with the increase of blending proportion of low sodium coal.When 75%DN2 or DN3 is blended,the slagging tendency of blended coal is lower than that of DN4 alone,which can solve the problem of slagging easily when burning high alkali coal alone.

关 键 词：高碱煤 低钠煤 混煤燃烧 煤灰成分 结渣特性 

分 类 号：TQ534[化学工程—煤化学工程]