Effective waste management through Co-pyrolysis of EFB and tire waste: Mechanistic and synergism analysis.

Driven by the need for solutions to address the global issue of waste accumulation from human activities and industries, this study investigates the thermal behaviors of empty fruit bunch (EFB), tyre waste (TW), and their blends during co-pyrolysis, exploring a potential method to convert waste into useable products. The kinetics mechanism and thermodynamics properties of EFB and TW co-pyrolysis were analysed through thermogravimetric analysis (TGA). The rate of mass loss for the blend of EFB:TW at a 1:3 mass ratio shows an increase of around 20% due to synergism. However, the blend's average activation energy is higher (298.64 kJ/mol) when compared with single feedstock pyrolysis (EFB = 257.29 kJ/mol and TW = 252.92 kJ/mol). The combination of EFB:TW at a 3:1 ratio does not result in synergistic effects on mass loss. However, a lower activation energy is reported, indicating the decomposition process can be initiated at a lower energy requirement. The reaction model that best describes the pyrolysis of EFB, TW and their blends can be categorised into the diffusion and power model categories. An equal mixture of EFB and TW was the preferred combination for co-management because of the synergistic effect, which significantly impacts the co-pyrolysis process. The mass loss rate experiences an inhibitive effect at an earlier stage (320 °C), followed by a promotional impact at the later stage (380 °C). The activation energy needed for a balanced mixture is the least compared to all tested feedstocks, even lower than the pyrolysis of a single feedstock. The study revealed the potential for increasing decomposition rates using lower energy input through the co-pyrolysis of both feedstocks. These findings evidenced that co-pyrolysis is a promising waste management and valorisation pathway to deal with overwhelming waste accumulation. Future works can be conducted at a larger scale to affirm the feasibility of EFB and TW co-management.

Environment impact and bioenergy analysis on the microwave pyrolysis of WAS from food industry: Comparison of CO2 and N2 atmosphere.

The alarming output of waste activated sludge (WAS) from industries requires proper management routes to minimize its impact on the environment during disposal. Pyrolysis is a feasible way of processing and valorizing WAS into higher-value products of alternate use. Despite extensive research into the potential of WAS through pyrolysis, the technology's long-term viability and environmental impact have yet to be fully revealed. In addition, the environmental effects of utilizing different pyrolysis atmosphere (N2 or CO2) has not been studied before, although benefits of CO2 reactivity during pyrolysis have been discovered. This study evaluates the process's environmental impact, carbon footprint, and bioenergy yield when different pyrolysis atmospheres are used. The global warming potential (GWP) for a functional unit of 1 t of dried WAS is 203.81 kg CO2 eq. The heat required during pyrolysis contributes the most (63.7%) towards GWP due to high energy usage, followed by the drying process (23.6%). Transportation contributes the most towards toxicity impact (59.3%) through dust, NOx, NH3 and SO2 emissions. The initial moisture content of raw WAS (65%) greatly impacts overall energy consumption and environmental impact. Pyrolysis in an N2 atmosphere will result in a higher overall bioenergy yield (833 kWh/tonne) and a lower carbon footprint (-1.09 kg CO2/tonne). However, when CO2 was used, the specific energy value within the biochar is higher (22.26 MJ/kg) due to enhanced carbonization. The carbon content of gas derived increased due to higher CO yield. From an energy perspective, the current setup will achieve a net positive bioenergy yield of 561 kW (CO2) and 833 kW (N2), where end products like biochar, bio-oil and gas can be used for power production. Despite the energy-intensive process, microwave pyrolysis has excellent potential to achieve a negative carbon footprint. The biochar used for soil amendment served as a good carbon sink. The utilization of CO2 as carrier gases provides a pathway to utilize anthropogenic CO2, which helps reduce global warming. This work demonstrates microwave pyrolysis as a negative emission, bioenergy-producing approach for WAS disposal and valorization.