Resource- and energy-efficient methane (CH4) transformation to fuels and chemicals is a research topic with societal, environmental and industrial relevance owing to the great variety of methane sources, including existing gas networks, small natural gas fields, shale gas, coal beds, agricultural biogas, deep-sea methane hydrates and the pressing issue of methane flaring in remote locations. In addition, CH4 and carbon dioxide (CO2) are the two greenhouse gases contributing majorly to global warming and their effect is expected to increase in years to come due to the continuously increasing energy demand worldwide. In this frame, CH4 reforming by CO2 (dry methane reforming) by means of different catalytic materials and technologies has been investigated over the years as a potential route for valorisation of the two molecules.@en

The present article demonstrates a superior catalytic performance of glycerol-enriched calcium oxide for biodiesel production than other calcium-based counterparts. The proficiency of glycerol-enriched calcium oxide in catalyzing the methanolysis of crude Jatropha curcas oil containing high free fatty acids content was systematically researched by examining the effects of glycerol dose, temperature, time, methanol-to-oil molar ratio and calcium oxide (CaO) amount on the process. Acid value of oil was lowered by 49 times and the maximum oil conversion of 96.1% was reported after the methanolysis reaction that indicated the improved performance of calcium oxide, after its treatment with glycerol, in accelerating biodiesel production from crude oil with very high free fatty acids amount. An interaction between the reaction variables, their influence on the methanolysis and optimum conditions affecting the process were moreover determined by means of the regression analysis (response surface methodology). The statistical analysis suggested that both CaO amount and mole ratio of methanol-to-oil had a significant impact on the current biodiesel production process.

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A series of ruthenium-doped strontium titanate (SrTiO₃) perovskite catalysts were synthesized by conventional and microwave-assisted hydrothermal methods. The structure was analyzed by X-Ray diffraction (XRD) confirming the formation of the perovskite phase with some TiO₂ anatase phase in all the catalysts. Microwave irradiation decreases the temperature and time of synthesis from 220 °C for 24 h (conventional heating) to 180 °C for 1h, without affecting the formation of perovskite. A 7 wt. % ruthenium-doped SrTiO₃ catalyst showed the best dielectric properties, and thus its catalytic activity was evaluated for the methane dry reforming reaction under microwave heating in a custom fixed-bed quartz reactor. Microwave power, CH₄:CO₂ vol. % feed ratio and gas hourly space velocity (GHSV) were varied in order to determine the best conditions for performing dry reforming with high reactants conversions and H₂/CO ratio. Stable maximum CH₄ and CO₂ conversions of ∼99.5% and ∼94%, respectively, at H₂/CO ∼0.9 were possible to reach with the 7 wt. % ruthenium-doped SrTiO₃ catalyst exposed to maximum temperatures in the vicinity of 940 °C. A comparative theoretical scale-up study shows significant improvement in H₂ production capability in the case of the perovskite catalyst compared to carbon-based catalysts.

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The complexity and challenges in noncontact temperature measurements inside microwave-heated catalytic reactors are presented in this paper. A custom-designed microwave cavity has been used to focus the microwave field on the catalyst and enable monitoring of the temperature field in 2D. A methodology to study the temperature distribution in the catalytic bed by using a thermal camera in combination with a thermocouple for a heterogeneous catalytic reaction (methane dry reforming) under microwave heating has been demonstrated. The effects of various variables that affect the accuracy of temperature recordings are discussed in detail. The necessity of having at least one contact sensor, such as a thermocouple, or some other microwave transparent sensor, is recommended to keep track of the temperature changes occurring in the catalytic bed during the reaction under microwave heating.

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