Ash deposition in the Coal Fired Flow Facility while burning Illinois (number sign)6 coal.

摘要

Deposition of coal fly ash and potassium sulfate on tubes representative of superheaters and intermediate temperature air heaters at the DOE Coal Fired Flow Facility during a 2000 hour POC test period is herein described. The deposition is unique to this test facility because of the high combustion temperatures and the use of potassium carbonate as the conducting ''seed.'' This seed material is required for coal fired MHD applications as a means to control sulfur dioxide emissions as it combines with the sulfur in coal to form potassium sulfate. Most of the potassium sulfate solids removed are in the form of a fine ash from which potassium can be recovered and recycled. Testing clearly indicated that the majority of ash/seed deposits can be removed by conventional sootblowing. A significant difference in ash removal is the increased volume of deposits, as potassium compounds make up 75% of the total deposits which must be removed for efficient heat transfer. Tube deposits on the heat exchange surfaces in the area of highest gas temperature have been difficult to remove due to the presence of molten potassium sulfate.