Abstract:

Chemical upcycling soapstock into biofuels is of great significance to reduce environmental pollution and achieve carbon neutrality. Biofuels were produced from soapstock by pyrolysis and subsequent catalytic vapor-phase hydrotreating in a pressurized two-stage fixed bed reactor. The effects of soapstock pyrolysis, non-catalytic and catalytic vapor-phase hydrotreating on the production of n-alkanes were explored. The reaction mechanism of n-alkanes obtained from the pyrolysis and catalytic vapor-phase hydrotreating of soapstock was proposed. To maximize the production of n-alkanes, the process parameters including pyrolysis temperature and hydrogenation temperature were optimized. Experimental results indicated that the primary intermediates of pyrolysis were completely deoxygenated and hydrogenated with Ni/Al₂O₃-SiO₂ catalyst, and the relative content of C₅—C₁₇n-alkanes increased from 15.8% to 97.3%, compared with that of the non-catalytic. The yield of n-alkanes initially increased and then decreased with increase of pyrolysis temperature, and the highest yield was observed at 550℃. The yield of n-alkanes gradually decreased with increase of hydrogenation temperature, and the highest yield was observed at 300℃.

Key words: soapstock, pyrolysis, hydrogenation, biofuel, n-alkane

摘要：

皂脚的资源化、高值化利用对减少环境污染和实现碳中和具有重要的意义。本文以皂脚为原料，采用双级加压固定床为反应器，对其进行热解-催化气态加氢处理以制备生物燃料。研究了皂脚热解-非催化和催化气态加氢处理对产物正构烷烃的影响，并提出了皂脚热解-催化气态加氢制备正构烷烃的反应机理。以最大化生成正构烷烃为目标，又对热解温度和气态加氢温度工艺参数进行了优化处理。实验结果表明，与非催化条件相比，在Ni/Al₂O₃-SiO₂催化剂的作用下，热解初级中间体被完全脱氧和氢化，使得C₅~C₁₇正构烷烃的相对含量由15.8%增加至97.3%。随着热解温度的升高，正构烷烃的产量先升高再降低，550℃时产量最高；随着气态加氢温度的升高，正构烷烃的产量逐渐降低，300℃时产量最高。

关键词: 皂脚, 热解, 加氢, 生物燃料, 正构烷烃