The direct carbon fuel cell technology provides excellent conditions for conversion of chemical energy of carbon-containing solid fuels directly into electricity. The technology is very promising since it is relatively simple compared to other fuel cell technologies and accepts all carbon-reach substances as possible fuels. Furthermore, it makes possible to use atmospheric oxygen as the oxidizer. In this paper the results of authors' recent investigations focused on analysis of the performance of a direct carbon fuel cell supplied with graphite, granulated carbonized biomass (biocarbon), and granulated hard coal are presented. The comparison of the voltage-current characteristics indicated that the results obtained for the case when the cell was operated with carbonized biomass and hard coal were much more promising than those obtained for graphite. The effects of fuel type and the surface area of the cathode on operation performance of the fuel cell were also discussed.
The paper presents the results and analysis of biomass processing in order to provide the conditions for the most profitable use of the biomass in modern and efficient power generation systems with particular attention put on the decrease of the emission of carbon dioxide (CO2) and no need to develop carbon capture and storage plants. The promising concept of CO2 storage via the production of biochar and the advantages of its application as a promising carbon sink is also presented and the results are supported by authors’ own experimental data. The idea enables the production of electricity, as well as (optionally) heat and cold from the thermal treatment of biomass with simultaneous storage of the CO2 in a stable and environmentally-friendly way. The key part of the process is run in a specially-designed reactor where the biomass is heated up in the absence of oxygen. The evolved volatile matter is used to produce heat/cold and electricity while the remaining solid product (almost completely dry residue) is sequestrated in soil. The results indicate that in order to reduce the emission of CO2 the biomass should rather be ‘cut and char’ than just ‘cut and burn’, particularly that the charred biomass may also become a significant source of nutrients for the plants after sequestration in soil.