Evaluation on hydrothermal gasification of waste tires based on chemical equilibrium analysis

Massive amounts of waste tires are produced globally, which brings great challenges to the disposal and recycling of used tires. Hydrothermal gasification is a promising option for recycling waste tires. The hydrothermal gasification of waste tires was evaluated based on the chemical equilibrium analysis along with the response surface methodology (RSM) in terms of subcritical temperature range (250-300 degrees C), transition temperature range (350 -400 degrees C), supercritical temperature range (550-600 degrees C), supercritical pressure (22.5 -30.5 MPa) and feedstock concentration (5-20 wt%). CH4 yield at 350 degrees C reached a maximum, 41.575 mmol/g. H-2 yield increased from 0.0283 to 53.602 mmol/g with increasing the temperature from 250 degrees C to 600 degrees C. CH4 yield at the supercritical temperature increased with lifting the feedstock concentration, while H-2 yield decreased. The optimal parameters regarding maximum H-2 and CH4 yields in the subcritical temperature range were 300 degrees C, 22.5 MPa and 12.5 wt%, respectively, while they in the supercritical temperature range were 550 degrees C, 30.5 MPa and 5.4 wt%, respectively. RSM was more suitable for predicting H-2 yield in the hydrothermal gasification of waste tires at subcritical and supercritical temperature ranges, but it was available for predicting CH4 yield in three temperature ranges. This study can provide basic data for the hydrothermal treatment of waste tires. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

A large amount of waste tires is produced globally, and hydrothermal gasification is a promising option for recycling them. This study evaluated the hydrothermal gasification of waste tires based on chemical equilibrium analysis and response surface methodology. The research provides basic data for the hydrothermal treatment of waste tires.