ASTM D6781-02 (R2021) pdf free download.Standard Guide for Carbon Reactivation.
1.1 This set of guidelines is offered to users of activated carbon to provide a better understanding of the reactivation process and some of the problems associated with sending carbon offsite or to a third party for thermal reactivation. It is not intended to serve as an operating procedure for those companies or persons that actually operate reactivation facilities. This is true because each reactivation facility is unique, using different types of furnaces, using various operating and performance requirements, and running spent activated carbons either in aggregate pools (combining different suppliers of carbon) or in custom segregated lots. Additionally, proprietary
information for each facility relative to the particular equip- r meni used cannot he addressed in a general set of guidelines.
3. Terminology
3. I Definitions:
3.1.1 reactivated carbon—spent activated carbon that has gone through a thermal reactivation process.
3.1.2 spent activated carbon—activated carbon that has seen service in some application, and that has some adsorbate on the carbon.
3.1.3 virgin carbon—activated carbon produced from a raw material carbon source that has never seen service.
4. Procedure
4. 1 The rinal Reactivation Process:
4.1.1 In order to appreciate the parameters or properties of the spent activated carbon that influence the success of the reactivation process. one must have a basic understanding of the reactivation process and the equipment used therein. Basically, the equipment and process used for reactivation is similar, if not identical, to those same items used for activation of coal, coconut, wood, or other chars, into activated carbon, post devolatilization and carbon fixation (which are necessary StepS in virgin carbon manufacture).
4.1.2 The equipment used for these types of processes usually consists of rotary kilns, vertical tube furnaces, fluidized beds, or a multiple-hearth furnace. All of these can be fired directly or indirectly. Auxiliary equipment to the furnace or kiln consists of feed screws, dewatering screws, direct feed bins, dust control equipment, product coolers, screening equipment. off-gas pollution abatement equipment. and tank- age.
4.1.3 The spent carbon can come from either liquid or gas phase service. Thus, the spent carbon will contain more or less water (or other liquids) depending on its service—less for gas phase service compared to liquid phase service. Additionally, the carbon could he fed to the furnace as a water slurry if received in a hulk load, or if the spent carbon was slurried out of adsorbers. Gross dewatering of such a slurry is normally done by gravity separation of the water from the carbon in an inclined dewatering screw.
4.1.4 Once the spent carbon is introduced into the reactivation furnace, the carbon undergoes a three-step process.ASTM D6781 pdf download.