In the use of today's air compressors, everyone has been thinking about the air compressor mainframe, how the quality is, and what needs to be paid attention to and maintained during the service cycle. But everyone has neglected a lot in other facilities. Often when there is a problem in the later stage, I still only think about what happened to the air compressor. In daily use and maintenance, we are most likely to overlook one thing, that is, the maintenance and maintenance of the air storage tank of the air compressor. As a result, the gas storage tank is rusted or corroded. So what is the real cause of the rust or corrosion of the gas storage tank?
Air compressor storage tanks will inevitably cause rain, air, or humid atmosphere corrosion after long-term use or use for many years. These corrosions are caused by the action of water, oxygen, acidic pollutants and other substances in the atmosphere. Steel rusting under natural atmospheric conditions is one of the most common atmospheric corrosion phenomena.
There are three types of atmospheric corrosion
1. Corrosion in dry atmosphere. At this time, there is basically no water vapor in the atmosphere, and ordinary metals form an invisible oxide film at room temperature. The surface of the steel remains shiny.
2. Corrosion in humid atmosphere. It refers to the corrosion of metal under a thin film layer that is invisible to the naked eye. At this time, there is water vapor in the atmosphere. When the water vapor concentration reaches the critical humidity (the critical humidity of iron is 65%, the critical humidity of copper is close to 100%), there is a thin water film on the metal surface, and uniform corrosion will occur. If there are pollutants CO2, H2S, SO2, etc. in the atmosphere, the corrosion will accelerate significantly. Steel corrosion under atmospheric conditions is actually electrochemical corrosion under water film conditions.
3. Corrosion of gas storage tanks can be seen under liquid film conditions. Refers to the relative humidity in the air at about 100% or corrosion caused by rain and other aqueous solutions. At this time, moisture forms droplets on the metal surface, and there is a water film visible to the naked eye.
Influencing factors of atmospheric corrosion
1. The influence of water. Among the substances corrosive to steel in the atmospheric environment, water is the main factor (generally speaking, the higher the humidity, the stronger the corrosiveness). The corrosion principle is as follows: a. Water is an electrolyte and can also dissolve a large amount of ions , Causing metal corrosion. b. Water can be dissociated into H+, OH—, and the difference in pH has a significant effect on the dissolution and corrosion of metals and oxides.
2. The influence of SO2. In areas polluted by industrial waste gas, SO2 has the most serious impact on steel corrosion. The exhaust gas fueled by petroleum, natural gas, and coal contains a large amount of SO2, and the corrosion rate of steel plates increases with the increase of the SO2 content in the atmosphere.
3. The influence of ocean and atmosphere. The atmosphere near the ocean contains a certain amount of salt, and its main component is NaCl, Cl—which is highly corrosive, so it can aggravate corrosion. The farther away from the ocean, the less salt in the atmosphere, and the smaller the amount of corrosion.
4. Other influences. In the atmospheric environment of oil production, there may be a lot of harmful substances such as Cl2, NH3, H2S solid dust particles, and their corrosion to the steel of the gas storage tank increases with the increase of the content. The synergistic effect of several substances will lead to increased corrosion of steel.
In the process of configuring the air compressor, you may pay attention to the air storage tank to protect the air storage tank. When replacing an air compressor or maintaining an air compressor, the use of the air storage tank should be considered to ensure the normal use after replacement and avoid affecting the normal air use of the enterprise.