The corrosion phenomena are considered the main problems for air preheater in thermal power plant. The boiler flue gas contamination leads to decrease the air preheater performance and increases the maintenance cost, which causes the degradation of the cold end heating elements and thus leads to decrease the heat recovery rate. In this study, a numerical investigation was done for the transient thermal behavior and the pressure drop of the standard regenerative air preheater model (st.), evaluating the performance factor, then modifying the air preheater model (mod.) by changing the plates at the cold end last basket to the coarse gravel media. Since the gravel media have low thermal conductivity and predicted to give a high pressure drop, a new technique was done for the modified air preheater to compensate the low heat transfer rates and reduce the pressure drop in the gravel media by inserting bypass tubes at different ratios (BR=4%, 6% and 8%) through the metal and the gravel media, where BR is the ratio of the tubes facing area relative to the matrix facing area. The numerical investigation was carried out for the Reynolds number based on the test duct hydraulic diameter at a range of 32000
Volume 12 | Issue 3
Pages: 353-364
DOI: 10.5373/JARDCS/V12I3/20201201