PAPCO Industries offers a Finite Element Thermal Analysis program that can help avoid severe damage to ducts and the frames of expansion joints caused by acid condensate formation. Acid condensate is formed when the flue gas temperature is reduced to its dew point. Control of flue gas temperature is achieved by properly placing insulation on the exterior of the ducts and by proper material choice and construction of insulation layers in the flexible element of a non-metallic expansion joint. The expansion joint system is designed to produce the necessary temperature drop to prevent overheating of the structural/gas seal layer while also maintaining the temperature of all pressure containing boundaries of flue gas, metal or otherwise, above the dew point at all times. Using computer simulations, PAPCO can determine whether the expansion joint is constructed properly to meet extreme conditions.
PAPCO performs proprietary Finite Element Thermal Analyses on the situations that result in the maximum temperature extremes to be certain that the structural/gas seal layer is not overheated and all pressure containing boundaries in contact with the flue gas are above the dew point temperature. The first extreme case is found when the flue gas is at its normal temperature during the winter months with the coldest ambient temperature and with a wind blowing. These conditions will result in a situation most likely to produce an acid condensate. The second extreme case is produced during an increase in flue gas temperature, possibly resulting from an air heater failure, during the summer when the ambient temperature is the highest with no wind. These conditions will result in a situation most likely to overheat the structural/gas seal layer.
With the results of the Finite Element Thermal Analysis, the expansion joint design will be altered as needed to produce the optimum results. Typical alteration would be changes in the Insulation Pillow thickness and location of the Teflon® Dew Seal ply in the Flexible Element. Also, if warranted, recommendations regarding the contiguous external duct insulation will be offered.
For more information call 201-767-9051, Fax: 201-767-7870 or visit www.papcoindustries.com
Papco Industries, Inc.