(14) The simple spray type desuperheater is used in applications where the steam load remains relatively constant.
Cooling water is injected into the superheated steam through a nozzle. The steam temperature is reduced by evaporative cooling. The maximum turndown ratio of the spray type desuperheater is 2:1.
(11) The venturi design uses the velocity of the steam to atomize the cooling water and effectively increase the turndown ratio
to 10:1. The cooling water entering the unit is preheated in a circulatory chamber located at the entrance of the inner
venturi. The water is then introduced into the inner venturi through a series of engineered jet ports and is atomized by
the steam.
(12) The ejector type desuperheater can be used over a wide range of steam flow rates and can operate with a turndown ratio of
50:1. This design uses a small amount of high-pressure steam to atomize the cooling water in the mixing chamber. The
expansion of the atomizing steam creates a depression in the mixing chamber while cooling water is ejected into the
chamber. Both flows are thoroughly mixed and discharged into the main process steam.
