Evaluation of the catalytic activity of borax and its calcined derivatives for pyrolytic valorization of waste tire tube rubber for production of oil and gases

Borax and its calcined derivatives were used in pyrolytic valorization of tire tube rubber to produce high value oil and gases. This work involved the preparation and characterization of catalysts and optimization of the reaction parameters for the catalytic and non-catalytic pyrolysis of waste tire tube rubber. The derivatives of borax catalyst were prepared by calcining it at 600 °C, 800 °C and 1000 °C. The borax derivatives were labeled as borax-600, borax-800 and borax-1000 and used for the pyrolysis of waste rubber. The outcomes of the catalytic and thermal pyrolysis processes were compared to check the effectiveness of the borax derivatives as a catalyst. Both processes produced different quantities of oil, gas and char specifically in case of borax catalyzed and borax-1000 catalyzed reactions. The oil product of thermal pyrolysis was composed of 15 compounds while borax catalyzed pyrolysis produced oil with 14 compounds. On the other hand, all borax derivatives produced oil having nine compounds. The oil contained aliphatic and cyclic hydrocarbons along with small quantities of sulfur and phosphorous containing organic compounds. The results of distillation showed that thermal pyrolysis produced 83.80 volatile oil while borax catalyzed pyrolysis produced 83.84 volatile oil. The oil content decreased to 66.34 with an increase in borax calcination temperature. Similarly, thermal pyrolysis produced 12.56 residue while borax catalyzed reaction produced 16.10 residue. The residue decreased slightly with a rise in calcination temperature. © 2021, Akadémiai Kiadó, Budapest, Hungary.