Why is the oil-injected air compressor replaced by a water-lubricated air compressor?

Why should ordinary oil injection screw air compressor be replaced by water lubrication air compressor?

Let's first understand what is the oil content of the air.

Compressed air as the second largest power energy after electricity, its application in all walks of life. Different industries have different requirements for the quality indicators of various pollutants in compressed air. Some industries have higher requirements for the quality of compressed air, and there is no lack of demand for oil-free compressed air.

However, many people usually have the following misunderstandings about oil-free compressed air: Most users only know that they need oil-free compressed air, but the concept of specific indicators is vague.

the oil removal equipment for compressed air on the market usually uses conventional filter purification equipment. The technology itself has the disadvantage that it cannot achieve continuous deep oil removal effect. In addition, few enterprises are equipped with oil content detection equipment. Therefore, once the compressed air quality does not meet the standard, most of them are simply considered to be pure oil pollution. Users generally believe that the gas produced by oil-free air compressors is oil-free compressed air.

In view of the above situation, we are here to explore the oil-free compressed air, mainly from the following issues to analyze.

1. What is oil in compressed air

there are clear definitions in ISO 8573-1-2010 "Compressed air Part 1 Contaminants and purity classes" and GB/T 13277.2-2015 "Compressed Air Part 2: Measurement Method of Suspended Oil Content": Oil refers to hydrocarbon mixtures composed of 6 or more carbon atoms (C6), collectively referred to as oil.

2. What is oil-free compressed air

before understanding oil-free compressed air, you need to understand the composition of oil in compressed air. Referring to GB/T 13277.1-2008 "Compressed Air Part 1: Pollutant Purification Level" (eqv.ISO 8573-1), it is clear that the oil in compressed air consists of three parts: liquid oil, suspended oil and oil vapor. We think that suspended oil is also a form of liquid oil, but it exists in the state of particles and has been suspended in gas through Brownian motion, oil vapor is a single molecule state exists in the gas. The sum of their contents is the oil content in the compressed air.

It can be seen from Table 1 that among the five levels of compressed air oil content, the level 0 standard is the total oil content ≤ 0.01 mg/m3 content standard formulated by the equipment user or manufacturer, while the oil-free compressed air is the oil content level equivalent to the level 0 standard, which can be quantified into specific index values.

3. The main source of oil in compressed air

in the previous article, we have defined the composition of the total oil content by reference to the standard: liquid oil, suspended oil and oil vapor. The source of the oil in the compressed air is mainly in the following two ways: one is the trace oil contained in the atmosphere itself, which mainly exists in the form of oil vapor, and the oil content varies with the degree of pollution of the air.

The second is the oil brought into the compression cavity through oil lubrication during the compression process. The most serious oil is the oil-lubricated screw compressor, because the air in the compression cavity will be fully mixed with the lubricating oil. The oil content of the compressor exhaust is controlled by the oil and gas separator provided by the compressor. The principle of oil and gas separation is to filter the oil in the compressed air through the collision and agglomeration of droplets and the filter materials with different apertures at a certain flow rate. When the oil and gas separator works normally, the oil content of the suspended oil is 1~3mg/m3, and the oil vapor content depends on the temperature of the compressed air.

4. Oil content in the atmosphere

the definition of oil in compressed air is C6 hydrocarbons, and in areas such as human gathering points, urban environment, industrial production areas and roads, as long as there are human activities, volatile organic compounds will inevitably be emitted to the outside, many of which have a large number of C6 hydrocarbons, so the ambient air must be oily.

As can be seen from the data in Table 2, the content of hydrocarbon compounds in the atmosphere of indoor, road and industrial areas is relatively high. The analysis is mainly due to the production of surrounding factories and enterprises or automobile exhaust emissions. The oil content value will be higher due to the easy accumulation of volatile organic compounds in the closed environment. In view of this, a set of data was also measured in the air compressor room of the factory, and the average value of oil content reached 0.297 mg/m.

5. Acquisition of oil-free compressed air

it is generally understood that the compressed air produced by an oil-free air compressor is oil-free, but this is not an accurate understanding. Oil-free lubrication compressor in the compression process without oil directly involved in the lubrication, the basic process can ensure that there is no oil pollution, but the oil in the ambient air can not be ignored, so the oil-free air compressor can not do a full range of our oil-free compressed air escort.

It is difficult to achieve the production of oil-free compressed air only by oil-free air compressors, and the most effective method is to configure reliable post-processing oil removal and purification equipment at the back end. With reliable oil removal and purification equipment support, the front-end air compressor is not limited to oil-free air compressor, the use of oil-lubricated air compressor can also achieve the acquisition of oil-free compressed air, which has a large number of examples in actual production. Therefore, after eliminating misunderstandings and re-understanding, how to obtain high-quality oil-free compressed air can have a correct direction.

If you need to purchase water-lubricated air compressors, oil-free air compressors and screw air compressors, you can contact Xiao Shen of Shanghai granklin group at any time. we will provide you with a brand-new stainless steel machine. the air compressor machine does not contain oil. Water is used as the lubricating medium to lubricate the air compressor head.