New concept for energy storage: Microwave-induced carbon gasification with CO2

Abstract

Energy storage is a topic of great importance for the development of renewable energy, since it appears to be the only solution to the problem of intermittency of production, inherent to such technologies. In this paper, a new technology for energy storage, based on microwave-induced CO 2 gasification of carbon materials is proposed. The tests carried out in this study on different carbon materials showed that charcoal consumes the least amount of energy. Two microwave heating mechanisms, a single-mode oven and a multimode device, were evaluated with the latter proving itself to be the more efficient in terms of energy consumption and recovery. The initial results obtained showed that this technology is able to achieve energy efficiencies of 45% at laboratory scale with every indication that these results can be improved upon to make this approach highly competitive against other energy storage technologies.

Boudouard reaction driven by thermal plasma for efficient CO2 conversion and energy storage

“…In this way high CO 2 conversion of 95% and process energy efficiency of 70% were achieved simultaneously [25] . This is an important step towards a commercially viable process to produce O 2 free CO gas from CO 2 and C. A question that could not be answered in our previous work was whether the high yield is simply due to heating the carbon to a high temperature by the thermal plasma, similar to the heating of the carbon by microwaves by Bermudez et al [23] , or excitation of the CO 2 by the plasma was responsible. To answer this question, we report here further studies on the plasma driven Boudouard reaction to elucidate the mechanism.…”

“…Recently, Bermúdez et al [23] investigated the Boudouard reaction of CO 2 flowed through a fixed bed heated by microwave induction. They tested four carbon materials, anthracite, activated carbon, charcoal and coke, and found that charcoal and activated carbon had the best reaction activity with CO 2 .…”

“…(5) ) of the process. Generally, the SEC is defined as the ratio of electric energy spent to the CO output, and the ERE is defined as the ratio of the combustion energy of the CO harvested to the electrical energy spent [23] . For this experiment, the specific expressions are…”

“…Temperatures above 1300 K are required for significant CO production rates. The conventional method to drive the reaction is to pass CO 2 gas through a carbon bed heated by a Lindberg tube furnace or by microwave induction [22][23][24] . Recently, Hunt et al carried out an experiment to compare the two heating methods [22] .…”

“…They claimed that the rate of CO production and electrical energy efficiency by microwave heating is superior to that by Lindberg tube furnace at carbon bed temperature lower than 1300 K. However, because the experimental process was not optimized, even in their microwave experiments, the CO 2 conversion and electrical energy efficiencies were no more than 35% and 6%, respectively. Bermudez et al improved these efficiencies by increasing the carbon bed temperatures up to about 1350 K by adjusting microwave power and the volumetric hourly space velocity of CO 2 pass through charcoal bed [23] . In their work, a CO 2 conversion of 95% was achieved with energy efficiencies up to 45%.…”