Feasibility Study of the Use of Non-Equilibrium Molecular Energy Distribution in the Steam-Coal Char Reaction. Final Report

摘要

A feasibility study of the use of non-equilibrium molecular energy distributions for the enhancement of the reaction velocity of the steam-coal char reaction has been carried out. The literature on the steam-carbon reaction has been examined. It is concluded that the evidence which supports the rate-limiting process as being the desorption of a surface oxide species in the form of carbon monoxide is quite convincing. Another part of this now-generally-accepted mechanism has the oxygen-exchange step in equilibrium. For the rate of the usual rate-limiting step to be increased by laser radiation, the carbon-carbon bond adjacent to the adsorbed oxygen species would have to be excited. The vibrational frequency of this bond is unknown, but the wavelength corresponding to this frequency is most probably somewhere in the range of 3-5 mu m. Lasers emitting light of the proper wavelength at sufficient power are now being developed, but are not yet available. It is recommended that further research be carried out to identify the frequency of the critical bond in the rate-limiting step of the steam-coal char reaction, that the surface diffusion step in this reaction be investigated to determine its effect on the reaction rate, and that some other gas-solid reaction systems be investigated so as to develop the techniques necessary for a successful study of the steam-coal char system. If these techniques are perfected, then when the appropriate laser becomes available within the next few years, the effect of laser radiation on the steam-coal char system may be studied in detail. The reaction, in theory, has good potential for stimulation by this technique, and should be investigated further. (ERA citation 08:003921)