高温再热对依兰煤低温干馏产物及结焦行为的影响

研究了依兰六级煤低温干馏气在高温二次加热过程中的裂解和结焦行为,分析了干馏气体产率、焦油产率的变化和加热器内的结焦情况。煤低温干馏终温600℃,干馏气二次加热温度600℃～750℃。研究表明,二次加热造成干馏产物中气体产率显著增大,焦油产率降低,加热器内存在结焦现象。提高二次加热的温度和延长气体在加热器内的停留时间,加剧了干馏气中烃类分子的裂解、缩聚和结焦,进一步降低了油品收率,并造成油品密度增大。温度对干馏产物中有机大分子裂解行为的影响更为显著,而停留时间和干馏气中烃类产物的浓度对缩聚反应的影响更大。

Impact of High-temperature and Re-heating on Low-temperature Pyrolysis Products and Coking of Yilan Coal

Low-temperature coal pyrolysis by gaseous heat carrier has the advantages to produce high-quality coal tar for fuel oil production.The behaviours of pyrolysis products of Yilan coal during high-temperature re-heating process were investigated by an inner-stiring pyrolysis reactor and a plug flow re-heating apparatus.The terminal pyrolysis temperature was 600℃and the re-heanting temperatures were 600℃-750℃.The results showed that the re-heating process could lead to the increase of gas yield and the decrease of tar yield.In addition,the coking was found in the re-heating apparatus.The effects were promoted by higher re-heating temperature,longer resident time and higher hydrocarbon content because of the hot cracking and the radical polymerization of the pyrolysis products.The hot ctacking was greatly influenced by the temperature,while the radical polymerization was greatly influenced by the resident time and the hydrocarbon content in the pyrolysis products.