In the use of air compressors today, everyone has been thinking about the main engine of the air compressor, what the quality is, and what needs attention and maintenance during the service cycle. But everyone has a lot of neglect in other facilities. Often when problems arise in the later stage, I still only think about what happened to the air compressor. In daily use and maintenance, we most easily overlook one thing, that is, the maintenance and maintenance of the air storage tank of the air compressor. As a result, the gas tank is rusted or corroded, so what is the real cause of the rust or corrosion of the gas tank?
The long-term use of the air compressor air storage tank or the use of it for many years will inevitably cause rain, air, or humid atmosphere corrosion, which is caused by the action of water, oxygen, acid pollutants and other substances in the atmosphere. Rusting of steel under atmospheric natural environment conditions is one of the most common atmospheric corrosion phenomena.
There are three types of atmospheric corrosion
1. Dry atmospheric corrosion. 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. Refers to the corrosion of metals 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%, and the critical humidity of copper is close to 100%), there is a thin layer of water film on the metal surface, and uniform corrosion will occur. If there are pollutants such as CO2, H2S, SO2, etc. in the atmosphere, the corrosion will be significantly accelerated. Steel corrosion under atmospheric conditions is actually electrochemical corrosion under water film conditions.
3. Corrosion of the gas storage tank under the condition of visible liquid film. Refers to corrosion in the air with a relative humidity of about 100% or in rain and other aqueous solutions. At this time, the moisture forms droplets on the metal surface to gather, and there is a water film visible to the naked eye.
Influencing factors of atmospheric corrosion
1. The influence of water. Among the substances that corrode 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 of pH value has obvious influence 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. Exhaust gas fueled by petroleum, natural gas and coal contains a large amount of SO2, and the corrosion rate of steel plate increases with the increase of SO2 content in the atmosphere.
3. The influence of ocean and atmosphere. The atmosphere near the ocean contains a certain amount of salt, the main component of which is NaCl, and Cl- has strong corrosiveness, 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 also increases with the increase of the content. The synergistic effect of several substances will lead to the intensification of steel corrosion.
In the process of configuring the air compressor, you may pay attention to the air storage tank and protect the air storage tank. When replacing the air compressor or maintaining the air compressor, the use of the air storage tank should be considered to ensure the normal use after replacement and avoid affecting the normal gas consumption of the enterprise.