Issues with post-compression air treatment

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Compressed air is being used more and more widely across various fields, which means that different requirements are placed on its quality. However, compressed air is generally subjected to post-treatment processes such as oil removal, water removal, and dust removal. The quality standards for compressed air vary depending on the industry or field in question; it is therefore necessary to first understand the classification criteria for water, dust, and oil. 1. The values for solid particle sizes from grade 0 to grade 5 shall be determined in accordance with ISO 8573-4 ； The values for grades 6 and 7 are determined according to recognized standards (see paragraph 4). https://pic2.zhimg.com/80/v2-f3f8fe45c855053302d54a1ea707e889_720w.jpg2. The values for humidity and the pressure dew point at the liquid water level shall be determined in accordance with ISO 8573-3; the liquid water content shall be determined using recognized standards (see paragraph 4). If a lower dew point is required, the dew point value must be clearly specified. https://pic2.zhimg.com/80/v2-61d44664ba5d3653b476796c615a6f8c_720w.jpg Standard levels for the pressure dew point of standard liquid water: 3. Oil grades; the values for aerosols and liquid oils should be determined in accordance with ISO 8573-2, while those for oil-gas mixtures should be determined according to ISO 8573-5. The total oil concentration is the sum of the aerosol value and the liquid oil value. https://pic3.zhimg.com/80/v2-37bc2931e2e40dba248f072e763f2afa_720w.jpg How to remove dust, water, and oil? The configuration can be carried out by referring to the ISO 8573-1 standard, or it can also be done based on the gas supply requirements specified by the equipment manufacturer. For dust removal, select the appropriate filtration precision based on the required level of compressed air; conventional dust removal filters will suffice, and they should be replaced in a timely manner according to their service life. For water removal, if the volume of water to be treated or the amount of air required by the equipment is not large, using a filter is more economical than a cold dryer. The standard procedure is to configure a cold dryer based on the required dew point; if a higher dew point is needed, then a desiccant dryer must be used. For oil removal, an approach similar to that used for water removal is adopted; if the gas consumption at the downstream stage is low or only minimal, it is recommended to use an activated carbon filter for adsorption. If the backend requires a large amount of oil-free gas, it is necessary to use oil removal equipment that can handle such volumes stably and continuously. The use of activated carbon filters is not recommended, as dealing with large amounts of gas necessitates a large number of filters; moreover, a series connection of activated carbon filters cannot ensure that each filter reaches its saturation point at the appropriate time, which may result in oily gas reaching the devices that use this gas at the backend. It is highly recommended to use currently mature oil removal equipment that employs catalytic oxidation for oil removal; such equipment can provide continuously stable grade-0 oil-free compressed air and can also eliminate active bacteria.