Why do some ozone destruct units have heaters?
Ozone gas applications can be either wet or dry. If the ozone is first contacted with water, such as in a contact tank for treating water, the ozone offgas is saturated. Even though the conversion of ozone to oxygen is exothermic, a heater is required to keep the catalyst material above the dewpoint. This is especially true on start-up of the destruct unit before it comes to temperature. This is also true if the exotherm is not enough to keep the catalyst dry. The catalyst will lose its reactivity if it becomes wet and must be either replaced or baked in an oven at 500F until it is dry. Examples of dry applications are those in which the ozone gas does not come into contact with water, such as in a CVD process, downstream of a gas phase process ozone analyzer, or in a process where excess ozone from a generator must be eliminated.
