微波耦合铁基催化剂辅助废塑料裂解脱氢研究

Research on microwave-assisted dehydrogenation of waste plastics over iron-based catalysts

塑料裂解脱氢可以实现废塑料的高值化利用。与传统塑料热解相比,微波催化可以在较短时间内实现更高的H_(2)产率和转化率。对比研究了不同结构的Fe基催化剂在微波场下对塑料脱氢产率的影响,探讨了催化剂组成与塑料脱氢活性之间的作用机制。结果表明,Al2O3负载型Fe催化剂和Fe-Al复合氧化物均可以获得较高的H_(2)产率,并促进碳纳米管的生成,后者的H_(2)产率可达46 mmol/g。通过X射线衍射和穆斯堡尔谱的表征分析,发现催化剂的微波吸收性能、催化剂中铁的形态和分散度是决定塑料在微波场下裂解脱氢性能的重要因素。此外,采用SiC管反应器屏蔽微波电磁场,研究了微波对塑料裂解脱氢反应的影响。在相同的温度条件下,SiC管反应器中的塑料裂解脱氢性能显著下降,证明微波电磁场对塑料裂解脱氢反应具有促进作用。

Plastic dehydrogenation facilitates the revalorization of discarded plastic.Compared with conventional plastic pyrolysis,microwave catalysis can achieve higher H_(2)yield and conversion in a shorter time.The effects of different structures of iron-based catalysts on the H_(2)yield in microwave field were studied,and the interaction mechanism between catalyst composition and dehydrogenation activity of plastic was discussed.Results showed that Al2O3-loaded iron catalysts and Fe-Al composite oxides can obtain high H_(2)yield and promote the generation of carbon nanotubes,with the latter achieving H_(2)yield up to 46 mmol/g.The microwave absorption properties,iron morphology,and dispersion of the catalysts play important roles in the dehydrogenation of plastic under microwave fields,as shown by X-ray diffractometry and Mössbauer spectroscopy.Furthermore,the effect of a microwave field shielded by a SiC tube reactor on the dehydrogenation of plastic was investigated.The results show that the amount of dehydrogenation of plastic in the SiC tube reactor decreases significantly under the same temperature conditions,which proves that the microwave field has a favorable effect on the dehydrogenation of plastic.