Promoted ammonium salt-protected activated carbon sorbent particles for removal of mercury from gas streams

A method for separating mercury from a mercury-containing gas stream, the method comprising:

• combusting coal in a combustion chamber, to provide the mercury-containing gas stream comprising Br′, HBr, or a combination thereof, wherein
• the coal comprises an NaBr additive, a CaBr2 additive, or a combination thereof, added to the coal before the coal enters the combustion chamber, or
• the combustion chamber comprises an NaBr additive, a CaBr2 additive, or a combination thereof, or
• a combination thereof;
• injecting ammonium bromide, ammonium sulfate, or a combination thereof into the mercury-containing gas stream;
• injecting activated carbon sorbent into the mercury-containing gas stream at or downstream of the injection of the ammonium bromide or ammonium sulfate into the mercury-containing gas stream, to add the Br−, HBr, or the combination thereof from the mercury-containing gas stream to the activated carbon, wherein the Br−, HBr, or the combination thereof is 0.1 wt % to 30 wt % of the activated carbon sorbent in the mercury-containing gas stream;
• contacting a mercury-containing gas stream with the activated carbon sorbent, to form a mercury-sorbent composition;
• and
• separating at least some of the mercury-sorbent composition from the mercury-containing gas stream, to give a separated gas.

A method for separating mercury from a mercury-containing gas stream, the method comprising:

• combusting coal in a combustion chamber, to provide the mercury-containing gas stream comprising Br−, HBr, HI, I−or a combination thereof, wherein
• the coal comprises an additive comprising Br2, a bromide, HBr, I2, an iodide, HI, or a combination thereof, added to the coal before the coal enters the combustion chamber, or
• the combustion chamber comprises an additive comprising Br2, a bromide, HBr, I2, an iodide, HI, or a combination thereof, or
• a combination thereof;
• injecting an ammonium salt into the mercury-containing gas stream;
• injecting activated carbon sorbent into the mercury-containing gas stream at or downstream of the injection of the ammonium salt into the mercury-containing gas stream, to add the Br−, HBr, HI, I−, or the combination thereof from the mercury-containing gas stream to the activated carbon, wherein the Br−, HBr, HI, I−, or the combination thereof is 1 wt % to 30 wt % of the activated carbon sorbent in the mercury-containing gas stream;
• contacting the mercury-containing gas stream with the activated carbon sorbent, to form a mercury-sorbent composition;
• and
• separating at least some of the mercury-sorbent composition from the mercury-containing gas stream, to give a separated gas.