Experimental investigation of the temperature distribution in a microwave-induced plasma reactor

It is urgent to reduce CO2 emissions to mitigate the impacts of climate change. The development of advanced conversion technologies integrated with plasma torches provides a path for the optimisation of clean energy recovery from biomass and wastes, thus substituting fossil fuels utilization. This article presents the temperature characterisation within a laboratory-scale microwave-induced plasma reactor operated with air, H2O and CO2 as the plasma working gases. The benefits associated with the plasma torch are highlighted and include rapid responses of the plasma and the temperature profile within the reactor to changing operating conditions. The average temperature near the side wall in the laboratory-scale reactor is proportional to the applied microwave power, ranging from 550 °C at 2 kW to 850 °C at 5 kW, while significantly higher temperatures are locally present within the plasma plume. The described system demonstrates promising conditions that are ideal for effective energy recovery from biomass and wastes into clean fuel gas

Hydrogen-rich syngas production from biomass in a steam microwave-induced plasma gasification reactor

Substitution of fossil fuels by sustainable practices must be rapidly implemented to mitigate the impacts of climate change. The conversion of biomass into combustible gas is investigated in a microwave-induced plasma reactor using pure steam as the plasma working gas for the first time. The optimum results are achieved at the highest forward microwave power of 6 kW with biomass carbon conversion efficiency over 98% and complete biomass energy recovery in syngas. Unreacted steam is simply condensed out, leading to the production of a syngas with low inert dilution and high calorific value in the range 10.5–12 MJ/Nm3. The syngas produced is rich in hydrogen, exceeding 60% by volume. The proposed process could aid in the transition to a carbon neutral economy as it has the potential to efficiently convert biomass to syngas that can be used for the sustainable generation of fuels, chemicals and energy