Catalytic potential of low-cost natural zeolite and influence of various pretreatments of biomass on pyro-oil up-gradation during co-pyrolysis with scrap rubber tires

This study investigates the influence of low-cost natural zeolite (NZ) catalyst, metallic content and various pretreatments of rice straw (RS) on quality and quantity of oil derived from co-pyrolysis and catalytic co-pyrolysis of RS and scrap rubber tire (SRT). Oil obtained from co-pyrolysis of combined acid washed and torrefied RS (WT-RS) and SRT (WT-RS/SRT) had 41% less oxygenates, 17% more hydrocarbons (HCs) and a significant amount of levoglucosan compared to the combination of raw RS and SRT (R-RS/ SRT). Besides, char from WT-RS/SRT combination had more HHV (30.15 MJ/kg) than that of R-RS/SRT combination (26.85 MJ/kg). NZ incorporation into co-pyrolysis enhanced deoxygenation by 34% for catalytic combination of R-RS/SRT/NZ than non-catalytic co-pyrolysis of R-RS/SRT combination whilst the combination of WT-RS/SRT/NZ encountered 77.27%, 61.53% and 65.51% more deoxygenation than R-RS/ SRT, WT-RS/SRT and R-RS/SRT/NZ combinations, respectively. An increase in HCs was found to be 40% and 31.25% for WT-RS/SRT/NZ contrary to WT-RS/SRT and R-RS/SRT/NZ, respectively. Additionally, 69.23% more mono aromatics along with more valuable gaseous composition were obtained in WT-RS/SRT/NZ than R-RS/SRT/NZ. HHV and physical characteristics of oil were superior for WT-RS/SRT/NZ. Results showed co-pyrolysis of pretreated RS-SRT as an effective route to improve product quality, which was further improved by the catalyst incorporation. (c) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This study investigates the impact of low-cost natural zeolite catalyst, metallic content, and various pretreatments of rice straw on the quality and quantity of oil derived from co-pyrolysis and catalytic co-pyrolysis with scrap rubber tires. The results show that the catalytic combination of pretreated RS-SRT is an effective route to improve product quality, with catalyst incorporation further enhancing the results.