水煤浆燃烧炉内固体残留物的微观分析

以不同特性煤浆的炉内燃烧固体残留物为研究对象，对取自炉内不同部位及沉积于硅碳棒和灰污探针上的典型燃烧灰的化学成分、矿物组成、元素分布及微观结构等进行分析研究。结果表明，水煤浆灰样中含Al、Fe、Ca的化合物和矿物的质量分数高于黑液浆，Na、K、S、Cl的情况与此相反。Fe的富集是造成水煤浆沾污结渣的根本原因。Na和Fe是引起黑液浆沾污结渣的主要矿物元素，Na的作用比Fe更大。黑液浆灰样中含有大量的霞石和硫酸钠等低熔融温度富钠化合物，Na是引起沾污结渣的根源。微观分析结果与实际燃烧状况是一致的，黑液浆结渣特性强于水煤浆，并且二者的灰沉积机理是不同的。

Microanalysis of solid residues from coal slurry fired furnace

The combustion residues of Xinwen coal water slurry (CWS) and black liquor coal slurry (CS) were studied. The typical combustion ashes sampled from different locations such as furnace wall, silicon carbide rod, heat flux probe et al. were analyzed in detail, including the chemical composition, mineral component, element distribution and microstructure. The results show that the content of compound and mineral phase comprising Al, Fe, Ca in the ash from combustion of CWS is higher than that of CS, while the case of Na, K, S and Cl is opposite. The enrichment of Fe in the ash is the reason of fouling and slagging during combustion of CWS, but Na and Fe are the essential mineral elements for the ash deposition of CS. Na plays more important role than Fe in the forming and developing of ash deposit in combustion of CS. The ash samples of CS are composed of many sodium rich and fusing temperature low minerals, such as nepheline, thenardite and hauyne. Hence, Na is the key element giving rise to severe fouling and slagging when black liquor coal slurry is fired in furnace, which is confirmed by microscopic analysis and practical burning test. The ash deposition trend for CS is much stronger than that for CWS, and their deposition mechanisms are different because of the existence of Na_2SO_4 and other S, Cl elements in the black liquor.