FeCl_(3)对稻壳水热炭基本元素及燃烧特性影响

EFFECTS OF FeCl_(3) ON BASIC ELEMENTS AND COMBUSTION CHARACTERISTICS OF RICE HUSK HYDROTHERMAL CARBON

以稻壳为原料,FeCl_(3)为催化剂,利用元素分析仪和热重法研究稻壳水热炭元素结构和燃烧特性,考察水热温度、催化剂浓度对于水热炭元素结构和燃烧特性的影响。结果表明:1)随着水热温度升高,水热炭固定碳含量和热值增大,O/C和H/C原子比逐渐降低。FeCl_(3)的加入进一步加深了水热炭的碳化程度,但对于碳化程度影响效果,水热温度大于FeCl_(3)浓度;2)未添加FeCl_(3)时,水热炭燃烧呈双峰,且挥发分燃烧段峰值明显高于固定碳燃烧段。水热温度上升,挥发分燃烧峰值下降,固定碳燃烧峰值增加。加入FeCl_(3)后,固定碳燃烧范围扩大,双峰逐渐融为单峰,整体向高温区转移;3)水热温度一定时,随着催化剂浓度增大,水热炭燃烧DTG曲线由双峰变为单峰,整体向低温区转移;4)升温速率加快,导致样品着火温度、燃尽温度提高,水热炭燃烧整体向高温区转移;5)水热温度一定时,FeCl_(3)加入后,着火温度和燃尽温度均小幅度提前,综合燃烧特性指数SN呈先增大后减小的趋势。FeCl_(3)提升了水热炭的能量品质及燃烧性能,为今后FeCl_(3)在生物质热转化应用上提供理论基础。

Using rice husk as raw material and FeCl_(3)as catalyst,the basic elements and combustion characteristics of rice husk hydrothermal char were studied by elemental analyzer and thermogravimetric method.The effects of hydrothermal temperature and catalyst concentration on the elemental structure and combustion characteristics of rice husk hydrothermal char were investigated.The results show as follows:1)With the increase of hydrothermal temperature,the fixed carbon content and calorific value of hydrothermal carbon increase,while the atomic ratios of O/C and H/C decrease gradually.The addition of FeCl_(3)further deepens the degree of carbonization of hydrothermal carbon,but the effect of hydrothermal temperature on the degree of carbonization is greater than the concentration of FeCl_(3).2)When no FeCl_(3)was added,the hydrothermal carbon combustion shows double peaks,and the peak value of volatiles is significantly higher than that of fixed carbon combustion.With the increase of hydrothermal temperature,the peak value o volatile combustion decreases and the peak value of fixed carbon combustion increases.After the addition of FeCl_(3),the combustion range of fixed carbon expands,and the double peaks gradually melt into a single peak,and the whole transferrs to the high temperature region.3)When the hydrothermal temperature is constant,with the increase of catalyst concentration,the DTG curve of hydrothermal carbon combustion changes from double peaks to single peak,and the overall transfers to the low temperature region.4)As the heating rate increases,the ignition temperature and burnout temperature of samples increase,and the hydrothermal carbon combustion shifts to the high temperature region.5)When the hydrothermal temperature is constant,the ignition temperature and burnout temperature advance slightly after the addition of FeCl_(3),and composite combustion characteristic index SNincreases first and then decreases.FeCl_(3)improves the energy quality and combustion quality of hydrothermal char,and provides theoretical basis for the application of FeCl_(3)in biomass thermal conversion in the future.