330MW燃准东煤电站锅炉烟气沿程灰沉积特性研究

Characterization of Ash Deposits along the Flue Gas for Zhundong Coal Combustion in a 330MW Boiler

准东煤作为优质的动力用煤因其在燃烧过程中沾污污、结渣问题严重,制约了此煤炭资源的有效利用。因而掌握其结渣、沾污机理对准东煤得以广泛应用有重要意义。文中借助ICP、SEM-EDX、XRD及灰熔点测试手段对燃烧准东宜化煤的330MW电站锅炉烟气沿程沉积样分析研究,结果表明:后墙水冷壁、后屏再热器至低温过热器处沉积样均由松散的大小不一的小球及渣块混合而成,分隔屏过热器与后屏过热器沉积样呈现大的骨架结构;根据沉积样形貌、组成成分及矿物组成分析,将沉积样分为硅酸盐类与硫酸盐类,分隔屏过热器与后屏过热器为硅酸盐类沉积样,后墙水冷壁、后屏再热器至低温过热器为硫酸盐类沉积样;硅酸盐沉积样黏度、灰渣熔点较高,而硫酸盐沉积样黏度及灰渣熔点较低。

Zhundong coal as a high quality steam coal has not been widely utilized due to its severe fouling and slagging problems during combustion. Understanding slagging and fouling mechanisms during coal combustion is crucial for the utilization of Zhundong coal. In this paper, the properties of ash deposits collected from various locations in 330MW boilers with Zhtmdong Yihua coal as the primary fuel were investigated by ICP-OES, SEM-EDX, XRD and Ash Fusion Point Determination Meter. Results show that ash deposits from R-WW, R-PR FR, FS and PS are composed of loosely distributedsmall balls and clinker, while deposits from D-PS and R-PS are made up of large body structures. The ash deposits can be classified into silicates and sulfates based on morphological, elemental and mineral analysis. The deposits from D-PS and R-PS contain more silicates and they are found to have high viscosity and high AFT, while the deposits from R-WW, R-PR, FR, FS andPS contain more sulfates and they have low viscosity and low AFT.