Which two 2 types of de aeration are used in steam boilers?

Which two 2 types of de aeration are used in steam boilers?

There are two basic types of deaerators, the tray-type and the spray-type: The tray-type (also called the cascade-type) includes a vertical domed deaeration section mounted on top of a horizontal cylindrical vessel which serves as the deaerated boiler feedwater storage tank.

How do you remove oxygen from boiler feed water?

Heat is the most common method for removing oxygen. Typical deaeration for smaller boilers utilizes a spray or combination spray and tray system to remove oxygen. The feed water is sprayed into a stream of 5 psig steam for efficient heat transfer and subsequent oxygen removal.

What is the purpose of deaeration?

Deaeration protects the steam system from the effects of corrosive gases. It accomplishes this by reducing the concentration of dissolved oxygen and carbon dioxide to a level where corrosion is minimized.

What is deaerator principle?

Principles of operation Thermal deaeration relies on the principle that the solubility of a gas in water decreases as the water temperature increases and approaches its boiling point. In the deaerator, water is heated up to close to its boiling point with a minimum pressure drop and minimum vent.

How do you remove co2 from boiler feed water?

Heating the feed water and maintaining it at a high temperature prior to its delivery to boiler, in the feed tank can drive off both oxygen & free carbon dioxide. Any remaining oxygen can then be dealt with by the addition of a chemical oxygen scavenger such as catalyzed sodium sulphite.

How do you remove oxygen from water?

Four common techniques for the removal of dissolved oxygen from water have been examined: boiling at 1 atm, boiling under reduced pressure, purging with N(2) and sonication under reduced pressure.

What is the function of economizer?

Economizers are heat exchangers that transfer the heat in the flue gas to another medium‚ generally the boiler feed-water‚ although other streams are sometimes used such as make-up water.

What is the percentage of air in water?

The solubility of oxygen in water is higher than the solubility of nitrogen. Air dissolved in water contains approximately 35.6% oxygen compared to 21% in air.

Why is pressure maintained in deaerator?

Steam pressure inside the deaerator has to be maintained to facilitate the removal of dissolved gases from water and also to provide adequate NPSH to boiler feed water pump. Deaerators are normally installed at high elevation in order to provide enough NPSH in the event of failure in steam pressure control also.

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