One Spray/Tray type deaerator include the followings:
• Complete set of parts including:
• Nozzles & Connections of controllers
• Steel structures, platforms, ladders, stairs.
A deaerator is defined as a mechanical device for removal of dissolved gasses, primarily oxygen and carbon dioxide, from water. For this purposes, we will consider only pressurized and sub atmospheric types which deaerated by contacting water with steam and elevating the temperature. Vacuum degasifiers remove dissolved gasses by reducing the pressure over the liquid without heating and will not be considered in this document. Also, in cases where the storage section is a separate vessel, the term deaerator is used to describe what might better be called the deaerator vessel or deaerator section.
The direct contact with steam will decrease the dissolved gasses and oxygen of the water to a maximum of 7 ppb. Also boiler water should be alkaline (8.5
This is common industry term for a type of deaerator also known as a spray-tray deaerator. Inlet water is sprayed into a steam atmosphere and falls onto a bank of trays through which the steam passed. Steam flow may be co-current, cross current, or counter-current to water flow.
This is the common industry term for a unit which might more properly be called a spray-scrubber or a spray atomizing deaerator. Inlet water is sprayed onto a steam atmosphere and falls onto a collector pan from which it flows into the scrubber/atomizer where it is mixed with incoming steam.
The storage section is an area in or below a deaerator which contains a specified volume of deaerated water. This may be contained in the lower portion of an integral unit or may be a separate tank located below the deaerator tank.
A vent is an opening in the deaerator through which the non-condensable gasses and some steam are released. This release is normally to the atmosphere, although it is possible to vent to a vacuum for special applications.
The design pressure and temperature are the pressure and temperature for which the pressure vessel is mechanically designed. The maximum allowable working pressure (MAWP) shall be equal to the design pressure, unless otherwise specified. The minimum design metal temperature (MDMT) shall be -20 oF, unless otherwise specified.
The operating pressure is the pressure inside the deaerator when operating. This pressure is important as it determines what the temperature of the deaerator effluent will be. The deaerator effluent temperature will be within 2 o F of the saturated temperature at the operating pressure.
An additional thickness of steel added to the pressure vessel in addition to that required to meet the structure requirements for pressure vessel design normally expressed.
Rated capacity is the total quantity of deaerator effluent including condensed inlet steam, water inlet, high pressure returns, and all other flows.
Flows which enter the deaerator of storage tank from higher pressure sources or sources such as high pressure feed water heaters.
They are the flows which enter the deaerator at elevated, but less than saturation, temperatures.
Un-deaerated flow which enters the deaerator and is saturated with dissolved non-condensable gasses at the temperature specified.
Safety relief valve is a device that protects the vessel against pressurization above the design pressure.