Abstract:
This study investigates the co-pyrolysis behaviors of bituminous coal (100%BC),
algae consortium (100%AC), and their blends at various blending ratios. The pure and
coal-biomass blends were characterized using CHN-S, GCV, and FTIR. Whereas, copyrolysis of blends were performed in thermogravimetric analysis (TGA). The
deviation between the experimental and calculated values of weight loss (WL%), the
residue left (RL%), and the maximum rate of weight loss (wt. %/min) was used to
calculate the synergistic effects. Kinetic parameters were investigated using TGA by
employing the Coats-Redfern integral method through eighteen reaction mechanisms.
The activation energy (Ea) for 100%BC was 85.04 kJ/mol through the F3 model, while
for 100%AC showed 78.22 kJ/mol using the D3 model. Thermodynamic parameters
such as Enthalpy (∆𝐻), and Gibbs free energy (∆𝐺) showed positive values, while
Entropy (∆𝑆) was negative for each coal-biomass blend. The catalytic co-pyrolysis of
the optimum blend (20BC-80AC) were studied using CeO2@MNA as a
multifunctional catalyst. Catalytic co-pyrolysis of the optimum blend in an in-situ
mixing with the catalyst CeO2@MNA was performed using TGA. The TG-DTG curve
shows the decomposition rate of the optimum blend (20BC-80AC) being affected by
the catalyst. The increased WL% shows a positive effect toward a higher yield of
volatile matter. The kinetic triplets and thermodynamic parameters were calculated.
The Ea of the optimum blend (20BC-80AC) in co-pyrolysis was further lowered
through catalytic co-pyrolysis. The Ea of the optimum blend (20BC-80AC) in the first
and second stages are (72.48 kJ/mol) and (13.76 kJ/mol), while 3wt.% further reduced
its Ea in both stages as (67.82 kJ/mol) and (41.21 kJ/mol). The use of CeO2@MNA at
3wt.% loading showed a reduction in the peak devolatilization temperature (Tp) of the
optimum blend substantially increasing the reaction rate, and reducing the Ea required
for the decomposition process.
