不同灰化温度下生物质混煤灰的烧结特性研究

选取晋城无烟煤和麦秆作为研究对象,利用压差法烧结温度测定装置测量不同灰化温度下煤和麦秆混合灰的烧结温度,再利用SEM-EDS以及XRD对灰样进行烧结特性分析。结果表明,不论灰化温度高低,随着麦秆的添加,煤和麦秆混合灰的烧结温度都呈现降低趋势,其降低幅度略有差别。灰化温度较低时,煤和麦秆混合灰的烧结温度低于灰化温度较高情况下混合灰的烧结温度。SEM-EDS分析表明,低温灰化得到的样品中出现较多不规则的纤维结构;较高温度下获得的灰样中出现较多致密的球状颗粒,这表明矿物质发生熔融形成球状颗粒。XRD分析表明,低温灰化烧结后的煤和麦秆混合灰样中因含有较多的含钾等碱金属系助融矿物质,导致混合灰样的烧结温度降低。然而,像钙长石等含钙矿物质本身具有较高的熔点,因此,在1 100℃时混合灰样具有较高的烧结温度。

Effect of different ashing temperatures on the sintering characteristics of ash from combustion of coal and biomass blends

Effect of ashing temperature on sintering behavior of ashes from combustion of coal and straw blends was investigated. Blends of a Chinese anthracite, Jincheng coal, and wheat straw were burned at three different temperatures. The resulting ash samples were then subjected to the sintering temperature measurement using a pressure-drop sintering device, morphological and mineralogical characterization with scanning electron microscope (SEM) fitted with X-ray energy dispersive spectroscopy (EDS) and X-ray diffractometry analyzer (XRD), respectively. For the same coal and biomass blends but different ashing temperatures, their sintering temperatures decrease in different extent. In addition, sintering temperatures of the blends under lower ashing temperature are lower than that under the higher ashing temperature. SEM imaging show that the texture of ash samples from lower ashing temperature is irregular, loose and more fibrous. The ashes under higher ashing temperature are mostly in spherical-shape, indicating ash melting has occurred during combustion. The XRD analysis reveals that blends of ash from Jincheng coal and straw under low ashing temperature has low sintering temperature due to more fluxing minerals, like K-containing mineral. The high sintering temperature of the ash blends depends on the Ca-containing minerals like anorthite with high melting temperature.