October 4-9, 2015
Activation process with water-steam of carbonaceous precursors leading to the production of active carbons is noncatalytic reaction, which takes place in a gas-solid system.
Transport phenomena within porous particles depend strongly on the internal structure of the particles. Not too much experimental work has been done to understand how the tortuosity and hence effective diffusivity within the pore space are affected by the pore size distribution, pore shape, and nanostructure (micro- and mesopores).
The activating gas in the process is thought to penetrate the particle as a result of diffusion accompanied by chemical reactions, the gas concentration decreasing with distance from the external surface. Moreover, the activation reaction is endothermic and this leads to temperature decrease in the reaction zone while heat energy flows slowly to the deeper layers of the particle. Because of these factors, the activating of carbonaceous substance is a function particle radius.
Active carbons (A-type, Poland) and N (Norit 2RL type, Holland) were subjected to abrasion in a spouted bed.
A method of successive removal of the layers from the carbon particles was applied. A diagram of the experimental equipment is shown in Fig 1
For core samples of active carbons so obtained, physicochemical properties were determined from densities measurements and by adsorption technique.
It has been shown found that there exists a correlation between the properties of samples obtained via abrasion technique, to the position within the active carbon particles. Anisotropy of nanostructure is due to conversion of the carbonaceous substance which reduces radially from the outer surface the particle to its inner core.
Bronislaw Buczek, "Testing of nanostructure within active carbons particles" in "Nanomechanical Testing in Materials Research and Development V", Dr. Marc Legros, CEMES-CNRS, France Eds, ECI Symposium Series, (2015). http://dc.engconfintl.org/nanomechtest_v/123