APT manufactured both vacuum and pressurized deaerators
Different deaerators manufactured by APT are:
Spray & Tray Deaerators incorporate a strong basic design that assures the performance over varying loads of incoming water. The process of Deaeration involves two main stages in which the steam and water move in opposite directions
Firstly water enters at the top of a deaerating tower in order to be sprayed through special designed self-adjusting stainless steel spray-valves into a steam atmosphere thus ensuring removal of gases and reducing the travel distance of air bubbles.
In the second stage the water rains through a series of specially designed stainless steel overflow trays, countercurrent to the steam. Steam enters from the bottom of the deaerating tower and flows upwards scrubbing out the last traces of the residual oxygen and carbon dioxide present in the water.
A vacuum deaerating equipment consists of a pressure vessel maintained at the saturation pressure of condensate water entering inside the deaerator. When the water entering inside the deaerator which is maintained at saturated pressure it will lose the holding property of dissolved oxygen and residual gases and the effluent water may be considered corrosion free from an oxygen or carbon dioxide standpoint.
A vacuum deaerator utilizes a water jet ejector to maintain the required vacuum inside the pressure vessel and by spraying the incoming water into an atmosphere of vacuum in the perforated section (Header).
In the first stage, the water reaches saturated pressure of water and virtually all of the oxygen and free carbon dioxide are removed. This is accomplished by spraying the water through self-adjusting spray valves which are designed to produce a uniform spray film under all conditions of load and consequently a constant flow and uniform gas removal are obtained at this point.
From the first stage the water containing minute traces of dissolved gases. This section consists of either a distributor or several assemblies of trays. Here the condensate in spread over the trays and the same is exposed to saturated pressure. Deaeration is accomplished at all rates of flow if conditions are maintained in accordance with design criteria. The water flows through the first stage water loses the property of the residual gases. In the first stage, most of the residual gases pass to the vent to the atmosphere. This assures that the deaerating equipment is adequately vented at all times.
The water which leaves the first stage falls to the storage tanks where it is completely deaerated and is heated to the steam saturation temperature corresponding to the pressure within the vessel.