Deaerator or Boiler Deaeration System

Deaerator is a device and process in which insoluble gases of oxygen and carbon dioxide are removed from the water entering the boiler. Pressure vessels or hot water boilers are used in various industries such as power plants, industrial plants and food, etc. In this group of equipment, due to the deposition of water oxygen in its walls, as well as the chemical reaction they perform with carbon dioxide, it leads to corrosion of the walls and damage to the boiler. Oxygen in water reacts with carbon dioxide to eventually produce carbonic acid, which is highly corrosive to metals. The use of a deaerator reduces the amount of insoluble oxygen in water and carbon dioxide and ultimately prevents corrosion of the boiler wall. Note that with increasing carbon dioxide in the water entering the boiler, the pH of the water is greatly reduced and eventually the environment becomes acidic and corrosion will occur over time. The procedure of the deaerators is based on this important rule that at saturation temperature, oxygen and nitrogen gases in the water are separated from it with the least pressure and will not be able to enter the boiler when leaving the deaerator. This law is known as Harry Dalton Law. What is the use of deaerator? In fact, the deaerator has two very important uses in the boiler, which are: · Deaeration of inlet water to the boiler · Preheat the inlet water to the boiler Dehydration and the main reason for its use were mentioned at the beginning of the text, but another very important application of the deaerator is its use in the preheating stage of water, which will have a great impact on the efficiency and performance of the boiler. Low temperature water entering the boiler causes heat shock which will cause a lot of damage to the boiler. In addition to reducing the life of the boiler, the steaming capacity of the device is greatly reduced by the entry of low temperature water into it. For this purpose, a deaerator is used to preheat the inlet water to the boiler. What are the working steps of deaerators? Regardless of the method of deaeration in the Deaerator, the steps to do this can be described as follows: · Water enters the deaerator · Deaeration with steam · Deaeration with oxygen absorber In short, the operation of different types of deaeration systems is such that first water enters the device and a large volume of insoluble gases and carbon dioxide are removed and transferred out of the outlet valve. In order to remove the amount of oxygen remaining in the water, oxygen absorbers are used, the most common of which include the following: · Sodium sulfite (Na2SO3) · carbohydrazide · Diethyl hydroxylamine (DEHA) · Nitrilotriacetic acid (NTA) · Ethylenediaminetetraacetic acid (EDTA) · Hydroquinone · Hydrazine (N2H4) Types of deaerators According to the work procedure and method used to separate oxygen and water-insoluble gases, boiler ventilation systems can be divided into two general groups, which are: · Tray-type deaerator · spray-type deaerator