Pyrolysis of lignite coal and waste tires for liquid fuel production

A thorough evaluation of all co-pyrolysis products (pyro-oil, gas, and char) using a fixed bed reactor is required for prospective upscaling and techno-economic analysis aimed at commercializing pyrolysis and integrating it into traditional systems. The study investigated the effects of many parameters, including the waste tire to coal ratio and temperature. This study investigates the co-pyrolysis of coal and waste tires (WT) to determine its influence on products throughout a broad range of feedstock ratios (10, 30, 50, 70, and 90 wt% of WT combined with coal) in a fixed bed reactor set at 500 °C. Based on the findings, it was determined that the optimal oil yield of 44 % and maximum gross calorific values of 41.00 MJ/kg were achieved with a coal to waste tires ratio of 50:50 which was slightly lower than 70:30 blending ratio. The findings demonstrated that the mass ratio of the feedstock was critical in the conversion of oxygenates into hydrocarbons (HC). Liquid yield, organic phase, aromatics, and aliphatic all increased when the WT/coal blending ratio approached 50:50. Pyro-oil output was 44 wt% with WT and coal (50:50), compared to 19 wt% with coal alone. Similarly, at comparable blend ratios, oxygenates were reduced by 65 %, and the higher heating value (HHV) of pyro-oil (41.00 MJ/kg) at 50:50 coal and WT blending ratio and matched that of WT (45.00 MJ/kg) and comparable with Petro-diesel. The incorporation of WT into coal resulted in a notable advantageous synergy for non-condensable gas. The introduction of WT augmented hydrogen (H₂) and methane (CH₄), alongside increased HCs, while diminishing carbon oxides compared to coal alone. The integration of WT into coal also enhanced the char properties, manifesting in heightened carbon content, HHV, and diminished ash content. The 50:50 blending ratio is deemed optimal following the discovery of a notable liquid yield at this proportion. Finally, Gas Chromatography-Mass Spectrometry (GCMS) and Fourier Transform Infrared Spectroscopy (FTIR) analyses were conducted on the pyro-oil, while Gas Chromatography-Thermal Conductivity Detection (GCTD) was employed for the pyro gas.