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摘要: 由于低阶煤缺乏黏结性,在工业型焦生产中的应用十分有限。为了利用低阶粉煤代替块煤作为原料生产清洁燃料,本研究采用洗油渣(WOR)作为黏结剂以增强其结构强度,并研究了黏结剂添加量和碳化温度对焦炭强度的影响。当碳化温度为800 °C,WOR与低阶煤的质量比为3∶7时,焦炭的抗压强度最好,M25达到97%。而煤热解固相产物的SEM分析表明WOR的热塑性是导致焦炭强度升高的主因,且黏结机理可总结为:热塑性的WOR在升温过程中软化熔融,包覆在煤颗粒表面且形成煤-黏结剂界面,将原本松散的惰性煤颗粒结合在一起,进而显著提高了焦炭强度。Abstract: Low-rank coal is rarely used in the industry of carbonized briquette due to its poor cohesiveness. In order to replace lump coal and utilize low-rank pulverized coal as much as possible in a carbonized briquette process, washing oil residue (WOR) was used as an enhanced binder to enhance the bonding strength of resulted carbonized briquette. The effects of blending ratio and carbonization temperatures on binding strength were investigated, and moreover, a reasonable bonding mechanism was deduced. The results showed that the best crushing strength was obtained when the weight ratio of WOR and low-rank coal is 3∶7 at 800 °C, and its crushing strength of M25 (M25) can reach to 97%, while the thermoplastic properties of WOR is thought to be responsible for the obtained good crushing strength, where WOR can be softened and coated on the surface of coal particles during carbonization, and then a coal-binder interface can be formed, resulting in the loose inert coal particles can be combined and the strength of coke is improved significantly.
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Key words:
- low-rank coal /
- washing oil residue /
- carbonization /
- bonding mechanism
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Table 1 Proximate and ultimate analyses of the coal sample and WOR
Sample Ultimate analysis wdaf/% Proximate analysis w/% C H N S Oa Mad Ad Vdaf G SXC 80.64 4.95 1.17 0.48 12.76 3.19 6.41 37.46 0 WOR 73.91 3.87 0.75 1.86 19.61 0.29 17.77 41.27 90 a: by difference -
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