Coked Shell surface areas

Physical Properties of Coked Catalysts. Surface areas for a series of Shell 244 (cobalt-molybdenum (Co-Mo) on alumina) catalysts varying from 0 to 22% coke were determined. The surface area is inversely proportional to coke deposition as shown in Figure 3. The catalysts with 10% coke deposit lose approximately 20% of their original surface areas. 

Figure 3. Effect of coke on surface area of catalyst. Catalyst used Shell 244 (Co-Mo on alumina).

In carbon adsorption, contaminants are physically attracted or adsorbed on the surface of the carbon. Adsorption capacities are high for carbon because its porous nature provides a large surface area relative to its volume. Activated carbon is prepared from lignite, bituminous coal, coke, wood, or other organic materials such as coconut shells. 

Table VII. Surface Areas and Pore-Size Distribution of Coked Shell 244 Catalyst...

The fractal approach was also used to investigate adsorption and desorption mechanisms of water vapor on active carbons that were derived from coconut shell, coal, coke and pitch fiber featuring a wide range of BET specific surface areas [78]. A values were measured for the water clusters adsorbed on primary carbon centers. Values ranging from 1.64 to 1.67 implied a diffusion-limited aggregation model on a pore wall plane, whereas higher A values (up to 1.86), measured at a relative pressure X = 0.95, implied the formation of water clusters that were partly merged vertically to the walls. 

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