| 摘要 |
Production of activated carbon at biomass-fueled steam/electric power plants (biomass plants) is described. At a typical biomass plant, various types of woody fuels are combusted to produce steam, and a steam turbine drives a generator to produce electric power. According to the invention, the biomass plant's existing fuel handling, combustion, and ash handling processes are replaced, in whole or in part, by pyrolysis, pyrolysis gas combustion, char activation, and activation offgas combustion using known methods. Carbonaceous feedstocks, typically nut shells which are known to produce high quality activated carbon, are pyrolyzed, producing char containing fixed carbon and ash, while the volatile constituents are driven off and collected. The char is activated by steam to produce activated carbon and syngas. Particulate matter is removed from the volatile pyrolysis products and activation offgas. A fraction of the gases are combusted to sustain the pyrolysis and activation processes and the remainder combusted in the biomass plant's existing combustion chamber to drive the steam/electric power generation process and also produce steam for the activation process. The sale of the activated carbon creates a significant new revenue stream. Application of the invention greatly improves the profitability of the combined operation and reduces air pollution from particulate matter. The reduction of particulate matter emissions, and sequestration of carbon in the activated product, may create additional economic benefits through the sale of air pollution credits and carbon credits respectively. |
