BFS Industries’ tray type deaerator utilizes two distinct stages to remove dissolved gases from feedwater:
1. The pre-heater section
2. The stainless steel tray section
The feedwater should be heated to a temperature approaching that of the deaerator operating steam pressure. The heated, partially deaerated water then enters the second stage (tray section), where contact time with the counter-current scrubbing steam is maximized. This forces the remaining traces of oxygen and carbon dioxide to be released from the liquid.
Tray Deaerator Operation
Stage One: Pre-heater Section
Incoming water enters the deaerator through spring loaded spray valves, directed downward into the steam atmosphere in the first stage pre-heater section. In the BFS tray type deaerator, this pre-heater section is fully enclosed within the stainless steel tray enclosure. There the water is heated to within a few degrees of the steam temperature in the deaerator. This is accomplished by spraying the water in a uniform, thin, continuous film. The surface tension of the liquid is broken, which facilitates the heating and the release of most of the non-condensable gases.
Stage Two: Stainless Steel Tray Section
The pre-heated water, containing traces of dissolved gases, then flows into the second stage, the tray section. Here, the water cascades down through the multiple layers of trays, with each tray pan spreading the water into a thin film before flowing down into the tray pans below. This mechanical scrubbing forces the remaining oxygen and carbon dioxide to the surface of the liquid, where they are liberated from the water. The process continues until the water reaches the bottom of the tray stack.
The steam enters this stage at the base of the tray stacks and flows upward through the space between the tray pans. The counter-current steam flow shakes loose the remaining dissolved gases, separating them from the liquid. Very little steam is condensed here, as the incoming pre-heated water has a temperature approaching that of the steam. The water leaving this stage – now completely deaerated and heated to the steam temperature corresponding to the saturated steam pressure within the vessel – falls into the storage section ready for use.
A reduction in temperature and pressure in the vent condenser area is created as the entering water condenses the steam atmosphere. The steam flows naturally up through the tray stack toward the lower pressure area of the vent condenser, carrying with it the liberated gases. Here most of the steam is condensed in the heating process, and the remainder carries the residual gases through the vent to the atmosphere.
Tray Deaerators from BFS Industries
Is a tray type deaerator right for your system? The BFS Industries team can create a custom-design solution from our ZER-O-PAC line of deaerators, whether tray type, packed column type, or spray type. Contact us today to get started.