Tri-reforming of surrogate biogas over Ni/Mg/ceria–zirconia/alumina pellet catalysts

Biogas Reforming to Syngas: A Review

Interest in novel uses of biogas has increased recently due to concerns about climate change and greater emphasis on renewable energy sources. Although biogas is frequently used in low-value applications such as heating and fuel in engines or even just flared, reforming is an emerging strategy for converting biogas to syngas, which could then be used to obtain high-value-added liquid fuels and chemicals. Interest also exists due to the role of dry, bi-, and tri-reforming in the capture and utilization of CO2. New research efforts have explored efficient and effective reforming catalysts, as specifically applied to biogas. In this paper, we review recent developments in dry, bi-, and tri-reforming, where the CO2 in biogas is used as an oxidant/partial oxidant. The synthesis, characterization, lifetime, deactivation, and regeneration of candidate reforming catalysts are discussed in detail. The thermodynamic limitation and techno-economics of biogas conversion are also discussed.

Perovskites in the Energy Grid and CO2 Conversion: Current Context and Future Directions

CO2 emissions from the consumption of fossil fuels are continuously increasing, thus impacting Earth’s climate. In this context, intensive research efforts are being dedicated to develop materials that can effectively reduce CO2 levels in the atmosphere and convert CO2 into value-added chemicals and fuels, thus contributing to sustainable energy and meeting the increase in energy demand. The development of clean energy by conversion technologies is of high priority to circumvent these challenges. Among the various methods that include photoelectrochemical, high-temperature conversion, electrocatalytic, biocatalytic, and organocatalytic reactions, photocatalytic CO2 reduction has received great attention because of its potential to efficiently reduce the level of CO2 in the atmosphere by converting it into fuels and value-added chemicals. Among the reported CO2 conversion catalysts, perovskite oxides catalyze redox reactions and exhibit high catalytic activity, stability, long charge diffusion lengths, compositional flexibility, and tunable band gap and band edge. This review focuses on recent advances and future prospects in the design and performance of perovskites for CO2 conversion, particularly emphasizing on the structure of the catalysts, defect engineering and interface tuning at the nanoscale, and conversion technologies and rational approaches for enhancing CO2 transformation to value-added chemicals and chemical feedstocks.

Thermodynamic modelling and optimization of oxy-reforming and oxy-steam reforming of biogas by RSM

In this study, a comparative thermodynamic equilibrium calculation of biogas oxy-reforming and oxy-steam reforming processes to produce syngas has been conducted by Aspen Plus simulation software. The effects of temperature (600-800°C), pressure (1-20 atm), and inlet O₂/CH₄ (0-1.0), H₂O/CH₄ (0-3.0), and CO₂/CH₄ (0.3-1.0) mole ratios on the equilibrium compositions of products were determined. The operation of the process was optimized using Gibbs free energy minimization method and statistical approach: response surface methodology (RSM). Optimum operating conditions CH₄/CO₂/O₂= 1:0.51:0.12 at 788°C and 1 atm for oxy-reforming and CH₄/CO₂/H₂O/O₂= 1:0.63:0.19:0.07 at 780°C and 1 atm for oxy-steam reforming were obtained to reach maximum H₂ yield, CH₄ and CO₂ conversions by minimizing carbon selectivity to produce syngas for methanol production.