Electrochemical oxidation of coal

After numerous studies, a cell for the electrochemical oxidation of coal was built (Figure 2.3). In this cell a tubular crucible consisting of a mixture of clay, cerium dioxide, and tungsten trioxide served as the electrolyte. The crucible was filled with powdered coke and placed into a clay vessel filled with annealed iron oxide (Fe304). At temperatures above 1000°C, the cell exhibited a voltage of 0.7 V and developed a power density (per unit of useful volume) of 1.33 W/dm. ... 

Dhooge, P. M. and Park, S. M. (1983) Electrochemistry of coal slurries - 2. Studies on various experimental parameters affecting oxidation of coal slurries. J. Electrochem. Soc. 130, 1029-1036. 

Coughlin RW, Farooque M (1980) Consideration of electrodes and electrolytes for electrochemical gasification of coal by anodic oxidation. J Appl Electrochem 10 729-740... 

A known solntion to this problem is creating and ntUizing power installations with coal-fired fuel cells (FC) [1-3]. As a rule, coal is first gasified, and then the prodncer gas is fed to fuel cells. However, carbon oxide, which is formed by partial oxidation of coal and hydrocarbons, is an extremely unstable compound that recombines, under specific conditions, to solid carbon, i.e. fuel soot, which clogs the FC pores and damages the electrochemical equipment. 

This opens up possibilities for an indirect electrochemical utilization of huge coal reserves. The possibility of direct electrochemical oxidation of carbon monoxide was soon questioned. It was suggested that hydrogen, rather than the carbon monoxide, is involved in the electrochemical reaction after being formed from CO by the Boudouard reaction ... 

A number of coal-derived liquids were examined by cyclic-voltammetry and other electrochemical techniques and found to show some activity. At anodic potentials films form on glassy carbon electrodes. It is suggested that this film formation is caused by oxidative coupling of radical cationic species with neutral ring structures through a mechanism similar to that which causes charring and coking in coal conversion processes. 

There are two possibilities for an electrochemical utilization of the chemical energy of coal (i) via prior coal gasification and the subsequent use of hydrogen and/or of carbon monoxide, thus produced, in various fuel cells and (ii) by a direct electrochemical oxidation within the fuel cell. For the first of these possibilities no insurmountable technical or scientific problems arise. Gasification units and proton-conducting membrane fuel cells are well known and very reliable devices, so, their use is connected only with economic and lifetime problems. 

The XPS technique has also been successfully used in the study of chemical groups formed on oxidation and eliminated on heat treatment on carbon foil, on carbons obtained by the electrochemical reduction of poly (tetra fluoro ethylene, PTFE), on bituminous coals,and on carbon blacks.The carbon Is synthesis of the XPS spectra for coal heated at 325°C obtained by Grint and Perry is shown... 

Marina, O.A., Pederson, L.R., Edwards, D.)., Coyle, C.A., Templeton, ).W., Engelhard, M.H., and Zhu, Z. (2008) Effect of coal gas contaminants on solid oxide fuel cell operation. Solid-State Ionic Devices 5 - 212th Electrochemical Society Meeting, October 7 12, 2007, Washington, DC, Electrochemical Society Inc, United states. 

There are two possibilities for electrochemical utilization of the chemical energy of coal (1) via prior coal gasification and use of the hydrogen and/or carbon monoxide produced in this process in various fuel cells, and (2) by direct electrochemical oxidation within the fuel cell. Various methods of coal gasification are discussed in Chapter 11. Some attempts to realize the second approach, which is basically a much simpler one-step process, are discussed in the present section. [Note that coal and carbon are somewhat interchangeable terms when... 

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