How to remove oil from air compressor condensate

Conclusion first

the oil in the condensed water is mainly removed by physical separation and adsorption. However, if the air compressor is lubricated with water at the beginning, there is no oil in the condensed water, and the oil removal does not exist directly.

First, let's talk about how the oil runs into the condensate.

For air compressors lubricated with oil, the lubricating oil is agitated by high temperature in the compression chamber, and part of it becomes a mixture of oil and gas and mixes into the compressed air. Although there is an oil and gas separation device behind, it is impossible to stop all the oil. There is always a small part of the oil mist running back with the air. When the air cools down, the gaseous water becomes liquid water, and the oil that hasn't been stopped is mixed in the condensate. Therefore, the water discharged from the oil-lubricated air compressor has a layer of oil flowers floating on it and muddy water below, which belongs to waste water that needs special treatment.

Three commonly used methods of oil removal

the first is gravity separation.

Pour the oily condensate into a large jar and let the water sit still. Oil is lighter than water and will float to the surface by itself. Then use the oil scraper to scrape off the slick, or use a straw to suck off the oil on the surface, and then drain the water below.

This method is the simplest and does not cost much money, but it can only remove large areas of oil floating on the surface. The dissolved and emulsified oil in the water cannot be removed, and the treatment is not clean.

The second is activated carbon adsorption

let the oil and water through a layer of activated carbon, activated carbon surface has a lot of tiny pores, can be dissolved in the water oil molecules and fine oil particles to absorb. After activated carbon filtration, the oil content in the water can drop a lot.

This method is more thorough than gravity separation, but the activated carbon will be saturated and will have to be replaced after a period of time, otherwise the oil will be spit out when it is full, causing secondary pollution.

The third is flocculation and filtration

add a flocculant to the oily water. This agent can make the small oil droplets in the water gather into large particles, and then block the large particles through the filter element. This method is suitable for wastewater with high oil content, and the effect is better than the first two, but the operation is a little more complicated, and the dosage needs to be controlled. The effect of adding more and adding less is not good.

Each of the three methods has limitations.

Gravity separation can only go to slick oil, not to dissolve oil. Activated carbon adsorption can dissolve oil, but consumables should be changed frequently. Flocculation and filtration effect is the best, but the operation is troublesome, and oily sludge needs to be treated separately. And no matter which method is used, the treated water cannot be discharged directly, and it must be tested to see if it meets the standard, and if it does not meet the standard, it must continue to be treated.

To put it bluntly, how to deal with the oily wastewater from the oil-lubricated air compressor is a long-term expense.

The water-lubricated air compressor made the degreasing thing disappear.

Water lubricated air compressor with water instead of lubricating oil, there is no oil in the compression chamber, so the compressed air-water mixture does not contain oil at all. After the separation of air and water, the condensed water discharged is clean water, which may bring a little dust in the air, but there is no oil.

Without oil, gravity separation does not need to be done, activated carbon does not need to be changed, flocculant does not need to be added, oily sludge will not be produced, and wastewater treatment equipment and consumables are available throughout the province. The discharged clear water can be directly recycled, and the returned water lubricating air compressor will continue to be used as lubricating water to form a circulation without any waste.

Therefore, the most thorough oil removal method is not to study how to remove oil, but to replace the water-lubricated air compressor from the source, so that the oil does not appear in the condensed water at all. For factories that have strict environmental protection or don't want to spend money on wastewater treatment, this is the real worry-free choice.