| abstract |
A method is provided for carbonizing and activating carbonaceous material, which comprises supplying the material to an externally fired rotary kiln maintained at carbonizing and activating temperatures, the kiln having a downward slope to progress the material as it rotates, the kiln having an atmosphere substantially free of oxygen provided by a counter-current of steam or carbon dioxide, and annular weirs being provided at intervals along the kiln to control progress of the material. There may further be provided an externally fired rotary kiln for carbonizing and activating carbonaceous material having a hollow rotary body that has a downward slope towards a discharge end thereof, and which is provided at intervals along its length with annular weirs for controlling progress of the carbonaceous material. In embodiments, there is also provided a process is for producing discrete solid beads of polymeric material e.g. phenolic resin beads having a mesoporous structure, which may be useful as feedstock for the above mentioned carbonization/activation process or which may have other utility e.g. as ion exchange resins. The process may produce resin beads on an industrial scale without aggregates of resin building up speedily and interrupting production. The process comprises the steps of: (a) combining a stream of a polymerizable liquid precursor e.g. a novolac and hexamine as cross-linking agent dissolved in a first polar organic liquid e.g. ethylene glycol with a stream of a liquid suspension medium which is a second non-polar organic liquid with which the liquid precursor is substantially or completely immiscible e.g. transformer oil containing a drying oil; (b) mixing the combined stream to disperse the polymerizable liquid precursor as droplets in the suspension medium e.g. using an in-line static mixer; (c) allowing the droplets to polymerise in a laminar flow of the suspension medium so as to form discrete solid beads that cannot agglomerate; and (d) recovering the beads from the suspension medium. There is also provided apparatus for forming discrete solid beads of polymeric material, said apparatus comprising: a first line for conveying s stream of a polymerizable liquid precursor; a second line for conveying a stream of a dispersion medium with which the polymerizable liquid precursor is substantially or completely immiscible; an in-line mixer configured to receive a combined flow from the first and second lines and to disperse the polymerizable liquid precursor as droplets in the dispersion medium; a vertical polymerization column configured to receive the dispersion medium with the droplets dispersed therein and to permit the polymerizable liquid precursor polymerize while descending the column in a descending flow of polymerization medium; and a vessel at the base of the column for receiving the descending flow of dispersion medium and collecting polymerized solid beads. |