Waste to energy (WTE) is one of the most reasonable managements for solving impacts of rubbish on our environment. Methods of WTE are major in incineration and gasification, by which to release thermal energy from organic substances. WTE plants have some more serious problems to solve because of the complexity of raw refuse. Refuse derived fuel (RDF) with specific pretreatment is confirmed as an optimum feedstock with higher efficient and more stable performance for incineration and gasification than the raw refuse. However, the RDF ash is still about 20% of original weight after burning. It needs to be considered how to dispose RDF ash in the right way. It is worth mentioned that RDF ash has specific property, such as low toxicity, well-distributed and inorganic nature. Therefore, some experts indicated that RDF ash could be used as source materials of building wall or road basement. This study focused on the characteristics of RDF ash such as weight, particle size, chemical composition, and discussed the mechanism of reaction change during the combustion. In this experiment, refuse from a WTE plant in Guangdong Foshan was made into RDF by screening and smashing process. Pelleted RDF made by additional extrusion and forming process. Ash samples were obtained from both pelleted and non-pelleted RDF burned at temperature of 600, 700, 800, 900, 1 000 and 1 100 ℃ in muffle furnace, respectively. The weight, particle size and chemical composition of these samples were analyzed. The results showed that chemical compounds of the RDF ash have decomposition reaction mainly below 1 000℃, such as decomposition of organic residue, chloride, sulfate, thus particle size decreased. While the burning temperature was rising over 1 000 ℃, combination reaction turned to be dominant during the whole reaction, the higher temperature is, the more serious reaction happened, which resulted in the products with composite silicates. Meanwhile, particle size increased and even formed into massive structure because more and more ash substances melted and bonded at or over their melting points. As a result, lump amounts increased after temperature returned back. Some compounds containing non-metallic elements such as C, Cl, S decomposed and turned into gaseous compounds, which escaped from the base-ash, so the ash weight reduced. High temperature burning reduced the weight of RDF ash. Compared with non-pelleted RDF ash, ash of pelleted RDF has more active at the same temperature, because of its higher density which means that there is shorter distance among reaction substances causing lower resisting force to overcome. Pelleted RDF ash contained more crystal substance quantities than the non-pelleted one, so it has bigger particle size, but the weight of the pelleted RDF ash is less than that of non-pelleted RDF ash.%以生活垃圾衍生燃料(refuse derived fuel,RDF)为研究对象,通过挤压成型的RDF与非成型的RDF在600~1100 ℃条件下灼烧,所产生的灰渣进行质量、粒径、化学成分等特性进行分析,探索RDF灰渣随温度变化的规律以及潜在的应用价值.研究结果表明,在1000 ℃以下,RDF灰渣随着温度提高,灰分组分发生分解反应,主要是残余有机物、碳酸盐、硫酸盐的分解,灰渣粒径减小;当温度升至1000 ℃以上,灰分组分发生化合反应,生成产物以复合硅酸盐为主,灰渣粒径增大甚至结块;灰渣在化学反应过程中,非金属元素C,Cl,S转化为气体化合物逸出主体,使灰渣质量减小;成型RDF灰渣晶体含量比非成型RDF高;成型RDF灰渣粒径比非成型RDF灰渣大.
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