高浓度煤粉流经文丘里管的管内黏附结垢现象

Experimental Study on Adhesion and Accumulation of Concentrated Pulverized Coal through Venturi

高浓度煤粉流经文丘里管时,会在收缩段和喉段内壁聚集黏附并形成坚硬垢层,造成相同输送压差下,输送量降低,文丘里管总压差增大。采集煤垢进行工业分析以及X射线荧光光谱、X射线衍射、扫描式电子显微镜和X射线能谱分析,结果表明,相对于煤粉,煤垢中的矿物质含量较高,主要矿物质元素在煤垢中富集程度较大,而且含有较多的以高岭石为主的黏土矿物。煤垢内表面相对平整,外表面矿物质元素含量最少,C元素含量最多。相对于普通直管部分,煤粉流经收缩段与喉段进口时强制贴近壁面运动,易形成牢固、坚硬的垢层。

The pulverized coal was adhered to the wall of convergent and throat section and formed a hard layer when concentrated gas-coal flew through Venturi, which resulted in a decrease in the conveying capacity and an increase in the total pressure drop of Venturi. The results from the industrial normal analysis, XRF, XRD, SEM and EDS showed that the accumulation contained relatively more content of mineral mainly consisted of Kaolin and major mineral elements compared to the pulverized coal. The inner layer of the accumulation was relatively flat, while in the outer layer there contained the least amount of mineral element and the most amount of carbon element. Compared to the straight part of the pipe, the coal particles were forced to flow more closely to the wall inside convergence and throat inlet section which is easier to form hard layer.