Preparation for high activity high density carbon
AssigneeWestvaco Corporation
InventorEdward D. Tolles
Life of this patent
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Abstract
Carbonaceous material is activated to produce a high activity, high density gas-phase activated carbon under conditions which effectively alter the particle pore size distribution to optimize the carbon's mesoporosity. The carbon is particularly suited for application in emission control for vehicles.
Claims14
A process for activating lignocellulosic material comprising the steps of:
- (a) blending together fragments of the lignocellulosic material with an activating agent selected from the group consisting of phosphoric acid and zinc chloride to effect chemical activation of the lignocellulosic material;
- (b) subjecting the blended materials to sufficient heat to effect plasticization of the acid-treated lignocellulosic material fragments to begin transition to thermoset;
- (c) densifying the heat-treated, acid-treated lignocellulosic material by mechanically shaping the plastic fragments in a spheronizer;
- (d) subjecting the shaped, acid-treated lignocellulosic material to sufficient heat for a sufficient time to effect thermosetting of the material;
- and
- (e) subjecting the thermoset, shaped, acid-treated lignocellulosic material to a final activation by heating the material to from about 425.degree. to about 650.degree. C. to produce an activated lignocellulosic material with a butane working capacity of greater than 15 g/100 cm.sup.3.
An improved process for preparing an activated carbon comprising blending lignocellulosic material fragments with a chemical activating agent selected from the group consisting of phosphoric acid and zinc chloride, heating to plasticize the blended material, shaping the heated blend fragments, and subjecting the shaped material to activation temperatures wherein the improvement comprises producing an activated carbon characterized by a butane working capacity of greater than 15 g/100 cm.sup.3 by densifying the carbon by shaping in a spheronizer the blended material fragments at transition point from being plastic to being thermoset and subjecting the shaped material to complete thermosetting of the material prior to subjecting it to activating temperatures.
Dependencies are inferred from the claim text.