高温熔渣对高碱煤碱金属捕捉特性研究

Experimental Study on the Alkali Metal Capture Characteristics of Slag at High Temperature

旋风燃烧技术是将煤中大部分灰在旋风燃烧器内形成液态渣膜并从锅炉底部排出的一种锅炉燃烧技术,高碱煤燃烧过程中释放的气相Na、K等碱金属在高温下与熔渣反应生成富含Na、K的低温共熔物,并随高温熔渣一起从锅炉底部排出,在解决新疆高碱煤强沾污结渣问题上具有一定的优势。实验研究了高碱煤在高温熔渣内燃烧过程Na、K、Ca、Fe等碱性金属的迁移、转换特性及其高温熔渣对碱金属的捕捉特性。研究结果表明:高碱煤与高温熔渣反应过程中挥发的Na、K、Ca、Fe、S等元素与高温熔渣反应,生成富含Na、K的变钾铁矾、三斜钾沸石、新硅钙石、白矾、斜钾铁矾等硫酸复盐和硅铝系复盐;煤中部分Na、K、S等元素通过高温熔渣的固化作用被固化至熔渣中,从而形成了一定量的富集。

Cyclone combustion technology could generate slag in the cyclone combuster and was used as slagging tap boiler.The gas phase elements such as Na,K etc.,which released from high-alkali coal during combustion process could react with slag and form some low Na,K-containing minerals.This paper simulated the coal combustion process in the melting slag and studied the mechanism of reaction between Na,K,Ca,Fe etc.,alkali elements and melting slag at high temperature.The experimental results showed that elements,Na,K,Ca,Fe,S could react with Si,Al-bearing minerals in slag and form anhydrite,willhendersonite,thenardite and bultfonteinite minerals,those Na-,K-,S-bearing minerals were solidified in the slag and tapped from the bottom of furnace.