Three Stage Process
1) Adsorption - In the adsorber, flue gas and ammonia pass through a slowly moving bed of activated coke. The activated coke adsorbs SOx and mercury at high efficiency and reduces NOx as a co-benefit.
Activated Coke (AC) is produced from coal and activated by steam. It has high mechanical strength against abrasion and crushing and high specific surface area for adsorption.
2) Regeneration - AC with adsorbed SOx and mercury is conveyed to the regenerator. Here, sulfuric acid or ammonium salts in the AC are thermally desorbed and decomposed to form a sulfur-rich gas steam for by-product recovery by thermal desorption.
After desorption the AC is cooled and passed through a vibrating screen to remove undersized particles. Replacement AC is added to the system, and the regenerated AC returns to the adsorber for use.
3) By-product recovery - The sulfur-rich gas from the regenerator is converted into a marketable sulfuric acid.