Solid Carbon Fuel Research Articles

Model of Carbon Utilization in a Solid Carbon Fuel Cell

The carbon fuel cell, a novel electrochemical conversion scheme for the production of efficient electric power from solid carbonaceous fuels, is investigated. A model of the carbon fuel cell is developed and validated, and a new definition for overall cell efficiency, which accounts for the partial utilization of the solid fuel, is proposed. Results indicate that the modeled cell geometry can operate in an optimal regime offering efficiencies near 60% and cell power densities of 100 mW/cm2 on a fuel bed height of 5 mm.

Experimental and Modeling Study of Biomass Conversion in a Solid Carbon Fuel Cell

Pulverized samples of charred biomass from rice straw, wood, almond shell, and corn stover were converted within a solid carbon fuel cell (SCFC) using a yttria stabilized zirconia oxide ion conducting electrolyte. Open circuit cell potentials against air for all solid fuels tested at 900°C were in the range 1.00 to 1.07 V, in good agreement with expected values. Measurements of cell performance indicated peak power densities of 34 to 39 mW/cm2 for the biomass fuels, which compared favorably with a peak power density of 38 mW/cm2 for an activated carbon fuel used for benchmarking purposes. Comparison with previous measurements for activated carbon in our laboratory, where peak power densities in excess of 220 mW/cm2 were demonstrated in optimized cells, suggests great promise for biomass utilization in a SCFC. Further modeling of corn stover and activated carbon revealed that the lower specific surface area and bulk density of the biomass chars is offset by a higher fuel reactivity in the dry gasification environment inside the SCFC anode compartment. The modeling also defined the limits of the SCFC operating window for high effective char utilization and demonstrated that high current densities can be supported when biomass chars are employed.

Model of Carbon Utilization in a Solid Carbon Fuel Cell

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Nuclear carbonization and gasification of biomass for effective removal of atmospheric CO 2

By the process of carbonization of biomass a portion of carbon element in biomass is stabilized as solid carbon, and the remaining portion of carbon, which is the volatile product from carbonization, is converted by the subsequent gasification and conversion process to carbon-neutral synthetic fuels, which can replace the fossil derived fuels currently used. In these processes, nuclear energy can effectively be utilized for supplying energy, thus avoiding the CO 2 emission from any biomass or fossil combustion. By utilizing nuclear energy, most of the carbons in biomass are converted to either stabilized solid carbon or carbon-neutral fuels. Thus, significant amount of CO 2 can efficiently be removed from the atmosphere by processing a part of annual growth of biomass, which leads to the decrease of atmospheric CO 2 concentration.

Effect of gas flow rates and Boudouard reactions on the performance of Ni/YSZ anode supported solid oxide fuel cells with solid carbon fuels

The effects of carrier gas flow rates and Boudouard reaction on the performance of Ni/YSZ anode-supported solid oxide fuel cells (SOFCs) have been studied with coconut coke fuels at 800°C. Decreasing flow rates of carrier gas from 1000 to 50mlmin−1 increased open circuit voltages and current densities from 0.71 to 0.87V and from 0.12 to 0.34Acm−2, respectively. The increased cell performance was attributed to the increasing extent of electrochemical oxidation of CO, a product of Boudouard reaction. The contribution of CO oxidation to current generation was estimated to 66% in flowing inert carrier gas at 50mlmin−1. The pulse transient studies confirmed the effect of flow rates on cell performance and also revealed that CO and CO2 can displace adsorbed hydrogen on carbon fuels. Flowing CO2 over coconut coke fuel produced CO via Boudouard reaction. The presence of CO led to a highest power density of 95mWcm−2, followed by a concurrent decline of power density and CO concentration. The declined power density along with decreasing CO concentration further verified contribution of gaseous CO to the power generation of C-SOFC; the decreasing CO concentration showed a typical kinetics behavior of Boudouard reaction, suggesting the loss of active sites on carbon surface for the reaction.

Reaction Mechanism of Solid Carbon Fuel in Rechargeable Direct Carbon SOFCs with Methane for Charging

Rechargeable direct carbon fuel cells (RDCFC) can be expected as portable power sources. The performance of power generation from RDCFCs was investigated here for various Ar flow rates into the anode. The fuel of solid carbon was charged by thermal decomposition of pure dry methane on the anode. The power generation time of RDCFCs depended on the flow rate of Ar fed to the anode to control the partial pressure of oxygen in the anode. The power generation time increased with increasing Ar flow rate in the range of , peaked at an Ar flow rate of about , and then decreased at . When was supplied into the anode after a charging of carbon fuel, was generated. The reaction gas of generated by electrochemical oxidation of carbon reacted with the deposited carbon (Boudouard corrosion) and produced . This can be used as fuel. The generation of permitted the efficient utilization of carbon during the power generation. By increasing the charging time up to , the power density increased to a maximum of .

Clean energy for 10 billion humans in the 21st century: is it possible?

One of the greatest challenges facing the global society of today and tomorrow involves the production of adequate, clean, sustainable energy for all people. It is clear that new technologies are required, nevertheless adequate energy can be provided by intelligent use of solar, geothermal and solid carbon fuels. The needed new technologies require integration of knowledge and expertise from science, engineering, and economics. New technologies are also needed for the management and use of wastes involved in energy production, including greenhouse gases.