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.

What is steam used for in a refinery?

Steam is also used for process heating, for pumping, and, in some refineries, for generating electric power. The condensate from the condensers and traps of these systems is usually reused as boiler- feed water or as makeup for other water needs.

Why do deaerator boilers feed water?

The purpose of a deaerator is to reduce dissolved gases, particularly oxygen, to a low level and improve a plant’s thermal efficiency by raising the water temperature. In addition, deaerators provide feedwater storage and proper suction conditions for boiler feedwater pumps.

What is Aru in refinery?

An amine regeneration unit (ARU) to regenerate the amine solution or specialty solvent. A sour water stripper (SWS) to remove ammonia and hydrogen sulfide from the sour process waters produced in the facility.

Which chemical is used in deaerator?

Deaeration steam: The most commonly used oxygen scavenger is sodium sulfite (Na2SO3). It is very effective and rapidly reacts with traces of oxygen to form sodium sulfate (Na2SO4) which is non-scaling.

Why do deaerators have pressure?

Deaerator uses Low pressure steam from the process plant at a pressure range between 0.5 to 1.5 bar. 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.

How does refinery produce steam?

Steam leaves the boilers at the highest pressure required by the process units or electrical generation. The steam pressure is then reduced in turbines that drive process pumps and compressors. Most steam used in the refinery is condensed to water in various types of heat exchangers.

What does a boiler do in a refinery?

Boilers are one of the most fundamental systems of a refinery or plant. They are literally the pieces of equipment that keep the plant up and running. They may be used to produce steam for powering turbines and pumps or for heating of facilities and processes.

How oxygen is eliminated in boilers?

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 SWS refinery?

Sour water stripping (SWS) is one of the first stages in the wastewater treatment process in many industrial operations, and especially in refineries. Water streams from throughout a refinery are typically sent to the stripper, which is designed to remove both H2S and ammonia from the water.

What is Hgu refinery?

The main Hydrogen Generation Unit (HGU) consists of feed Pre-desulfurisation section, followed by desulfurisation, reforming and process gas cooling with high temperature shift conversion to increase the hydrogen content of the process gas. Purification is done with a Pressure Swing Adsorption unit.

Why deaerator is kept at height?

Why are deaerators placed at height? Deaerators are placed at height to provide sufficient NPSHa (Net Positive Suction Head available) to the boiler feedwater pumps – the boiler feed pumps are typically situated low in the ship for the same reason.

How does a deaerator work?

Deaerators are mechanical devices that remove dissolved gases including oxygen from boiler feedwater. 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.

How do deaerators remove oxygen from the air?

Most deaerators are designed to remove oxygen down to levels of 7 ppb by weight or less, as well as essentially eliminating carbon dioxide. The deaerators in the steam generating systems of most thermal power plants use low pressure steam obtained from an extraction point in their steam turbine system.

Should I install a deaerator in my boiler plant?

Consider the feasibility of installing a deaerator. Prior to installation, the boiler plant is fed by feedwater from a vented feedtank operating at 80°C. This essentially means that each 1 000 kg of feedwater contains 5.9 gram of air.

How is deaerated water stored in a steam power plant?

The deaerated water flows down into the horizontal storage vessel from where it is pumped to the steam generating boiler system. Low-pressure heating steam, which enters the horizontal vessel through a sparge pipe in the bottom of the vessel, is provided to keep the stored boiler feedwater warm.