辣椒秆灰熔融特性分析

Fusion Characteristic of Capsicum Stalks Ash

分别对辣椒秆在400、600、815℃成灰灰样进行X射线荧光(X-ray fluore scence,XRF)、X射线衍射(X-ray diffraction,XRD)分析、灰熔融烧结及热重(thermo gravity,TG)试验。研究发现:不同温度成灰的形貌及元素比例均存在较大差异,成灰过程均未出现熔融结渣。但按煤质熔融特性指标进行理论计算的结果表明各温度成灰均已严重结渣,而灰熔点烧结仪试验发现各成灰温度灰样其变形、软化、半球和流动温度一致,均高于1100℃。对灰样进行TG实验,表明1100℃以后不同温度成灰的组分已一致,各温度成灰灰样含相同的起骨架支撑作用的高温熔融物质。XRF分析数据显示:随着成灰温度从400℃升高至600℃,灰样内K含量减少8.2%,Cl含量不变;当温度进一步升高至815℃,K含量减少16.6%,而Cl几乎全部析出。XRD分析表明:3个温度下灰样均含石英、铁酸钾、单钾芒硝与方镁石。400℃成灰还含方解石、碳酸钾钙石及钾盐,600℃时方解石与碳酸钾钙石消失,碳酸盐分解释放CO2,生成硅化钙,815℃成灰钾盐消失生成沸石。辣椒秆灰样的熔融特性主要取决于方镁石、石英、铁酸钾、单钾芒硝、沸石及硅化钙6种物质所生成的起骨架支撑作用的高温共融体。因此,实验中无论灰化温度为多少,其熔融特性均一致,评判辣椒秆生物质灰的真实熔融特性不应遵循煤质指标,而应从其本身所形成的共融物着手。

The capsicum stalk ashes prepared by ashing at 400, 600 and 815 ℃ were studied by X-ray fluorescence, X-ray diffractometer, thermogravimetry（TG） analysis and sintering test. It was presented that both morphology and proportion of elements of different temperature ashes were significantly different, melting and slagging didn＇t appear in the process of ashing. But according to the melting characteristics index of coal quality, it showed that the ashes had serious slagging tendency. Meanwhile, it was found that the deformation, softening, hemispherical and fluid temperatures were consistent in sintering test and were all above 1 100 ℃. TG results showed the ash components were same at about 1 100 ℃ and they had same high-temperature molten material. The content of K in ash reduced 8.2% from 400 ℃ to 600 ℃ and CI basically didn＇t change, K and Cl decreased by 16.6% and 97% from 600 ℃ to 815 ℃, respectively. Three kinds of ash were mainly inclusive of quartz, potassium iron oxide, microcline and periclase. Calcite and fairchildite decomposed and generated calcium silicate at 600 ℃, sylvite disappeared and generated zeolite at 815 ℃, which were all existed in ash prepared at 400 ℃. The fusion characteristics of capsicum stalk ash were mainly depended on the high-temperature molten material built up by periclase, quartz, potassium iron oxide, microcline, zeolite and calcium silicate. Therefore, no matter how much the ashing temperature was in experiment, ash melting characteristics were the same and the evaluation of biomass ash fusion characteristics should not follow the melting characteristics indexes of coal quality, but should be focused on the high-temperature molten material which provided a supporting effect of skeleton structure in biomass ashes.