废轮胎回转窑中试热解产物特性

Characteristics of pyrolytic products derived from pilot-scale pyrolysis of scrap tires in rotary kiln

热解反应在中温段(450～650℃)进行,油产率可达42.7%～45.0%.对热解油进行了实沸点蒸馏和红外光谱(FTIR)分析.热解油品质较轻,200℃以下轻馏分质量分数高达33%～40%,热解温度的升高有助于增加轻馏分质量分数.在较高热解温度下热解油具有较强的芳香性.热解油FTIR分析结果体现了芳烃类物质生成的DielsAlder反应途径.热解炭产率约为39%～44%,并具有高灰分(>12%)和高硫特性.热解炭具有较发达的中、大孔.在550℃前,热解炭比表面积随热解温度升高而增大;温度继续升高,比表面积变化不大.热解炭孔容积随热解温度升高而增大,并在550℃时达到最大值.在孔径约为50nm处,热解炭比孔容积具有最大值.

Scrap tires were pyrolyzed at 450-650°C, and the oil yield was 42.7%-45.0%. The complete distillation curves of oil were acquired. The light fraction below 200°C amounted to as much as 33%-40% and increased with pyrolysis temperature. Fourier transform infrared spectroscopy (FTIR) analysis of the pyrolytic oil showed that higher pyrolytic temperature yielded more aromatics in the oil. This phenomenon could be explained by the Diels-Alder route of the primary oil vapor to secondary aromatic compounds. The yield of pyrolytic char was about 39%-44%. Pyrolytic char contained relatively high content of ash (> 12%) and sulfur. The char had fairly developed mesopores and macropores. The surface area of the pyrolytic char increased with pyrolysis temperature before 550°C, while it was relatively stable at higher temperature. The pore volume of pyrolytic char increased with pyrolysis temperature and reached the maximum at 550°C. The maximum specific pore volume of char occurred at 50 nm pore diameter.