Recuperative Oxidizer with Energy Recovery

Recuperative thermal oxidizers have been used in industrial applications since the 1970's. The thermal efficiencies are normally in the 75% range. The combustion chamber reaches 1400 F to destroy 99.9% of the emissions. A minimum of 10% LEL level is required in order for the unit to operate effectively without consuming large amounts of auxillary fuel. The current technology of Regenerative Oxidizers has almost eliminated the need for Recuperative oxidizers.However, there are advantages to recuperative oxidizers:

1.) They can achieve 99.9% destruction efficiencies (regenerative are, in general, limited to 99.0%.)

2.) Visible emissions are destroyed (regenerative units with poppet valves allow a small quantity of visibles to escape when valves are switched.)

3.) Odors are destroyed (regenerative units with poppet valves allow odors to escape when the valves are switching positions every 4 minutes.) And, Recuperative units can handle particulate laden airstreams without plugging.

The Recuperative unit shown at the upper left is a 25,000 scfm with a 75% primary heat exchanger and a 60% secondary heat exchanger. The exhaust emissions are from a coating process with 10% LEL levels. The process has 8 oven zones and the secondary heat exchanger recovers enough energy to supply the required amount of heated air to operate the process without any auxillary fuel. The amount of energy recovered from this oxidizer system results in a net energy savings compared to operating the process without the oxidizer.

The image below is an example of a recuperative oxidizer and airflow configuration through the unit: