最小化二次反应下聚乙烯热解焦油特性

Polyethylene Pyrolysis Tar Characteristics Under Minimum Secondary Reaction

在400-500℃温度范围内,分别采用金属网反应器和水平管式炉开展了聚乙烯的热解实验。结果发现：金属网反应器的500℃热解焦油中检测到15.68%的环烷烃,而管式炉热解焦油中未检测到环烷烃的存在。结果表明：在二次反应存在的条件下,环烷烃会进一步分解为直链烷烃和烯烃。在100 K/s升温速率,热解终温500℃下,停留0.1 s时未检测到C≥31的烃,停留10 s时C≥31的烃含量为10.06%,当停留时间增加到30 s时,C≥31的烃含量增加到14.01%。因此,聚乙烯热解初期先释放出小分子量的烃,随着热解时间增长会有一部分大分子烃释放出来。

Within the temperature range of 400℃ to 500℃,the pyrolysis experiments of polyethylene were carried out in a wire-mesh reactor and a horizontal tube furnace respectively.The result shows that the naphthenic hydrocarbon,15.68%of the total weight of pyrolysis tar,was detected in the wire-mesh reactor under temperature of 500℃ while none of it was detected in the tar from the tube furnace.As is shown by the results that due to the secondary reaction,naphthenic hydrocarbon will further decompose into straight-chain paraffin and olefin.Under the heating rate of 100 K/s with the final pyrolysis temperature of 500℃,the hydrocarbon C≥31 was not detected when the holding time is 0.1 s.However,when the holding time increased to 10 s,the weight content of hydrocarbon C≥31 was 10.06%.And when the holding time increased to 30 s,the weight content of hydrocarbon C≥31 augmented to 14.01%.Therefore,small molecular weight hydrocarbons will be first released during the preliminary stage of polyethylene pyrolysis and some macromolecular hydrocarbons will be released with the increase of holding time.