PRODUCTION OF ACTIVATED CARBON FROM COAL CHARS USING MICROWAVE ENERGY
Titel:
PRODUCTION OF ACTIVATED CARBON FROM COAL CHARS USING MICROWAVE ENERGY
Auteur:
Norman, Loren M. Cha, C. Y.
Verschenen in:
Chemical engineering communications
Paginering:
Jaargang 140 (1994) nr. 1 pagina's 87-110
Jaar:
1994-10-01
Inhoud:
The microwave induced reaction of carbon with carbon dioxide has been investigated as a method of production of activated carbon using coal char. Factors which control the carbon-carbon dioxide reaction in a microwave environment were also studied. Results indicate that the reaction rate is primarily controlled by the electric field strength. The reaction rate or conversion follows an Arrhenius type relationship with substitution of the electric field strength for temperature. In other instances, temperature is easily determined and therefore used in these calculations. In this case, the particle temperature is nearly impossible to measure. This means that we need an easily calculated variable to use in our calculations. The input microwave power will serve as this variable. It is easily determined, and is also useful in calculations because, as stated earlier, when input power (in the form of electric field strength) is substituted for temperature in equations of the Arrhenius type, the reaction rate is related in a similar manner, Because of difficulties associated with the direct measurement of particle temperature in the microwave energy field, only reactor skin temperatures were measured. The char surface area, as calculated using the B.E.T. equation, was increased dramatically by the microwave process. The prod uct had a high degree of microporosity and was a good adsorbent of NOx gas in air. The solids residence time for the coal char in direct microwave contact was on the order of minutes. Reactor skin temperature measurements at the reaction zone suggest that reaction occurred at approximately 600°F(316°C).
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