Is It Worth Replacing Old Air Preheaters?

By Bob Dubil

We recently were asked our thoughts regarding whether it was worthwhile to consider replacing an old air preheater with one of today's new designs. The focus of the question revolves around how much improvement in preheater efficiency can be expected. The following summarizes items to consider.

The bottom line is that both types of air preheater have offsetting advantages and disadvantages. There have been little design changes in recent years, which have increased air preheater efficiency. However, most efforts seemed aimed at reducing manufacturing costs. It seems that most recent installations have been fixed-recuperative type, rather than rotary-regenerative type. I believe that this is due to lower first-cost and a willingness to operate the air preheater to failure, rather than spend more initially, and perform the continued maintenance necessary to maximize unit life.