Air preheater and method of decomposing and removing ammonium bisulfate from a regenerative heating element of that air preheater

A method of decomposing and removing ammonium bisulfate from a regenerative heating element of an air preheater for a solid fuel-fired power plant, comprising:

• restricting air flow over a selected portion of the regenerative heating element whereby ammonium bisulfate previously deposited on the selected portion is decomposed to loose, dry ash while simultaneously maintaining air flow over a remainder of the regenerative heating element to support operation of the solid fuel-fired power plant;
• and
• subsequently directing flue gas over the selected portion to sweep the loose, dry ash from the selected portion of the regenerative heating element.

A method of decomposing and removing ammonium bisulfate from a regenerative heating element of an air preheater for a solid fuel-fired power plant, comprising:

• selectively closing individual valves of a plurality of air flow control valves in order to provide an air flow shadow extending downstream over a selected portion of the regenerative heating element whereby ammonium bisulfate previously deposited on the selected portion is decomposed by retained heat to loose fly ash;
• and
• subsequently cleaning the loose fly ash from the selected portion of the regenerative heating element by passing flue gas over the regenerative heating element.