Phosphoric acid treatment of carbonaceous material prior to activation

An activated carbon for the removal of an impurity, the activated carbon prepared by a process comprising:

• selecting a raw material for direct-activation;
• applying a solution of at least 50% phosphoric acid by weight at a ratio of from 0.01 pounds to 0.3 pounds of phosphoric acid solution per pound to the raw material selected for direct activation to produce a phosphoric acid treated raw material;
• and
• direct-activating the phosphoric acid treated raw material via a gas activation process to produce an activated carbon.

A method for removing an impurity from a flue gas stream comprising:

• injecting an activated carbon into a flue gas stream upstream from a collection device, the flue gas stream comprising at least one impurity suitable for adsorption;
• allowing sufficient residence time for adsorption of the at least one impurity onto the activated carbon;
• collecting in the collection device the activated carbon after the activated carbon has adsorbed the at least one impurity;
• and
• removing the activated carbon and the absorbed at least one impurity from the flue gas stream;
• wherein the activated carbon is prepared by a process comprising:
• selecting a raw material for direct-activation;
• applying a solution of at least 50% phosphoric acid by weight at a ratio of from 0.01 pounds to 0.3 pounds of phosphoric acid solution per pound to the raw material selected for direct activation to produce a phosphoric acid treated raw material;
• and
• direct-activating the phosphoric acid treated raw material via a gas activation process to produce an activated carbon.

A system to remove an impurity from a flue gas stream comprising:

• a flue gas stream comprising at least one impurity suitable for adsorption;
• an injection point operable to facilitate the injection of an activated carbon into a flue gas stream, the flue gas stream comprising at least one impurity suitable for adsorption;
• and
• a collection device operable to:
• collect the activated carbon after the activated carbon has adsorbed the at least one impurity;
• and
• facilitate removal from the flue gas stream of the activated carbon and the absorbed at least one impurity;
• wherein the injection point is upstream from a collection device so as to allow for sufficient residence time for adsorption of the at least one impurity onto the activated carbon;
• and
• wherein the activated carbon is prepared by a process comprising:
• selecting a raw material for direct-activation;
• applying a solution of at least 50% phosphoric acid by weight at a ratio of from 0.01 pounds to 0.3 pounds of phosphoric acid solution per pound to the raw material selected for direct activation to produce a phosphoric acid treated raw material;
• and
• direct-activating the phosphoric acid treated raw material via a gas activation process to produce the activated carbon.

A method to produce lignite-based activated carbon comprising:

• applying a solution of at least 50% phosphoric acid by weight at a ratio of from 0.01 pounds to 0.3 pounds of phosphoric acid solution per pound to the lignite to produce a phosphoric acid treated lignite;
• and
• activating the phosphoric acid treated lignite via a gas activation process, the gas activation comprising exposing the phosphoric acid treated lignite to steam at a temperature of at least 600° C.;
• and optionally washing the resulting material with a solution comprising at least 1% hydrochloric acid by weight.

A method to produce walnut shell-based activated carbon comprising:

• applying a solution of at least 50% phosphoric acid by weight at a ratio of from 0.01 pounds to 0.3 pounds of phosphoric acid solution per pound to walnut shell pieces to produce phosphoric acid treated walnut shells;
• and
• activating the phosphoric acid treated walnut shells via a gas activation process, the gas activation comprising exposing the phosphoric acid treated walnut shells to steam at a temperature of at least 600° C.;
• and optionally washing the resulting material with a solution comprising at least 1% hydrochloric acid by weight.