PRODUCTION OF ACTIVATED CARBON FROM COAL CHARS USING MICROWAVE-ENERGY

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 mi crowave environment were also studied. Results indicate that the react ion rate is primarily controlled by the electric field strength. The r eaction 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 the se calculations. In this case, the particle temperature is nearly impo ssible to measure. This means that we need an easily calculated variab le to use in our calculations. The input microwave power will serve as this variable. It is easily determined, and is also useful in calcula tions because, as stated earlier, when input power (in the form of ele ctric field strength) is substituted for temperature in equations of t he Arrhenius type, the reaction rate is related in a similar manner. B ecause of difficulties associated with the direct measurement of parti cle temperature in the microwave energy field, only reactor skin tempe ratures were measured. The char surface area, as calculated using the B.E.T. equation, was increased dramatically by the microwave process. The product had a high degree of microporosity and was a good adsorben t of NOx gas in air. The solids residence time for the coal char in di rect microwave contact was on the order of minutes. Reactor skin tempe rature measurements at the reaction zone suggest that reaction occurre d at approximately 600 degrees F (316 degrees C).