Methods and apparatus for producing activated carbon from biomass through carbonized ash intermediates
Biomass combustion processes may be controlled to intentionally generate a carbon-containing ash, from which activated carbon is produced according to the methods disclosed. Some variations provide an economically attractive process for producing an activated carbon product, the process comprising combusting a carbon-containing feedstock to generate energy, combustion products, and ash, wherein the ash contains at least 10 wt % carbon; separating and recovering carbon contained in said ash; and further activating or treating the separated carbon, to generate an activated carbon product. Many process variations are disclosed, and uses for the activated carbon product are disclosed.
1. A method of using a biogenic activated carbon composition to reduce emissions, the method comprising:
(a) providing activated carbon particles comprising a biogenic activated carbon composition;
(b) providing a gas-phase emissions stream comprising at least one selected contaminant;
(c) providing an additive selected to assist in removal of the at least one selected contaminant from the gas-phase emissions stream;
(d) introducing the activated carbon particles and the additive into the gas-phase emissions stream, thereby adsorbing at least a portion of the selected contaminant onto the activated carbon particles, thereby generating contaminant-adsorbed carbon particles within the gas-phase emissions stream;
(e) separating at least a portion of the contaminant-adsorbed carbon particles from the gas-phase emissions stream, to produce a contaminant-reduced gas-phase emissions stream; and
thermally oxidizing the contaminant-adsorbed carbon particles, thereby regenerating the activated carbon.