Why can a deaerator remove oxygen?
Date: 2023-02-17Read: 48
1、 Why do we need to remove oxygen first
Due to excessive dissolved oxygen in the working fluid, it can cause corrosion and damage to thermal equipment, shorten its service life, and for furnace tubes, it may also cause frequent leaks, increasing the economic losses of the unit. So, it is necessary to remove dissolved oxygen from the water supply. So we need to use a deaerator.
2、 So why can a deaerator remove oxygen?When it comes to the question of why a deaerator can remove oxygen, we need to first understand two laws. One is Dalton's law of partial pressure, created by John Dalton in 1801, and the other is Henry's law, discovered by the British Henry in 1803 while studying the solubility of gases in liquids.Dalton's law of partial pressure states that the partial pressure produced by a gas in a gas mixture is equal to that at the same temperatureThe pressure generated when it occupies the entire container alone; The total pressure of a gas mixture is equal to the sum of the partial pressures of each gas in it.Henry's Law states that under isothermal and isobaric conditions, the solubility of a volatile solute (usually a gas) in a solution is proportional to the equilibrium pressure of the solute at the liquid surface.The main deoxygenation method of a deaerator is based on the above two laws, namely physical deoxygenation method.It is to heat the water in the deaerator to saturation temperature, so that the upper steam side space of the deaerator is completely filled with steam, and the pressure of other gases is close to zero(Referring to Dalton's law of partial pressure),At this point, other gases in the condensed water inside the deaerator are released (referring to Henry's law) and discharged from the deaerator, achieving the purpose of deoxygenation.So, in order to betterMany measures have been taken to heat the deaerator to saturation temperature.The first stage, which is the primary stage of deoxygenation, is used when the condensed water enters the deaeratorbutterfly shapenozzleMake the condensed water diffuse as much as possible to form a water film and increase the contact surface area between water and steam. Heating the condensed water quickly to saturation temperature can release most of the oxygen.The second stage, also known as the deep deoxygenation stage, is when water falls into the water side space of the deaerator and flows into the bottom of the deaeratorSteam disturbs the water in the deaerator, carrying other dissolved oxygen and gases out of the water surface for deoxygenation.Therefore, through the above content, we can learn the three necessary conditions for the normal operation of the deaerator. First, heat the water in the deaerator to the saturation temperature under pressure. Second, ensure that there is sufficient contact area between the condensed water and steam entering the deaerator. Third, there must be sufficient time to ensure that the gas analysis process is very thorough.
