Co-combustion of tyre waste char and biomass blends using thermogravimetric-mass spectrometric analysis

Abstract

Tyre waste chars from pyrolysis are a potential fuel source due to their attractive energy properties and high carbon content. However, the high concentration of sulfur in tyre char and the release of carbon dioxide (CO₂) when burned prevent its use as a fuel. In this study, Scenedesmus microalgae and torrefied pine wood waste were blended with tyre waste chars. Blending was done at varying biomass ratios. The aim was to evaluate the effects of biomass additions on tyre char combustion characteristics and gas emission resultants using the thermogravimetry-mass spectrometry method. Results show that the combination of biomass with tyre char significantly affects the physicochemical properties of the tyre char. Biomass enhances the combustion characteristics of tyre char. Ternary blends with optimised proportions of microalgae led to higher burnout temperatures and prolonged combustion phases. Torrefied wood–tyre char blends at a 90:10 ratio showed higher rates of CO₂ evolution, but adding torrefied wood at 15–20 wt% and increasing microalgae from 4 to 11 wt% reduced CO₂ emissions. The experimental results show that tyre char could be a potential combustion co-fuel with biomass feedstock and suitable for clean combustion applications. The study emphasises the critical role of incorporating clean, renewable biomass sources in mitigating gas emissions during the combustion of tyre waste chars, thereby promoting the sustainable utilisation of carbon resources. Additionally, the integration of biomass to enhance the usability of tyre waste chars presents a promising opportunity to improve the economic viability of the waste tyre pyrolysis process.

Significance:

Tyre char is a waste by-product from the pyrolysis of waste tyres. It possesses good energy properties and can be used as a fuel, but its combustion is undesirable due to the generation of carbon dioxide during combustion. The blending of tyre char with biomass material influences the physicochemical properties of tyre char and can have a consequent effect on the combustion characteristics of these chars. The addition of microalgae and torrefied wood at various blending ratios had a significant influence on the reduction of CO₂ emission patterns in the tyre char–biomass blends. Tyre char–biomass blends can be considered for cleaner combustion processes.