Analysis of the Smart Application of Oil-Free Air Compressor Rental in the Air Separation Industry

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As a key equipment, the air compressor is essential in air separation units, and it is also the major energy consumer in such units. During the operation of the air separation unit, any problem with the air compressor can severely affect its normal functioning. In Europe and the United States, the widespread acceptance and thorough understanding of leasing have enabled the efficient use of oil-free air compressor leasing in the air separation industry, as well as allowing many operational issues caused by air compressors to be solved in a very effective manner. Here, we will discuss and explore the application of oil-free air compressors in the air separation industry, hoping to serve as a starting point for further discussion. Firstly, the simplest application is during normal operation, when the air compressor fails and stops working, or when the compressor needs to be serviced but the air supply must not be interrupted. At this time, most factories have backup machines available, so considering turning on the backup machine is an option. However, in many specific industries, simply having a backup unit in place is not sufficient; the reliability of continuous gas supply must be absolutely guaranteed, such as in the semiconductor and electronics industry, as well as in the oil refining industry. At this point, a short-term rental of a suitable oil-free air compressor becomes an excellent option, as it can ensure the smooth resolution of short-term issues. Here, a special model deserves mention: the diesel-driven oil-free air compressor. It is of the twin-screw type and air-cooled; it does not rely on electricity or circulating water. It senses system pressure and starts automatically when the set low-pressure value is reached. This type of compressor offers many advantages when used as a backup unit. Such applications have also begun to be gradually accepted in China over the past few years, and their use is expanding steadily. Secondly, when installing new equipment, leased air compressor systems are used for tasks such as purging, pressurization, airtightness testing, drying, and commissioning. Since air separation plants are usually located in remote areas with inadequate supporting facilities, and issues often arise during the delivery, installation, and commissioning of self-purchased air compressors, renting an oil-free air compressor system can effectively solve these problems, allowing large issues to be addressed at a very low cost in order to ensure timely construction and commissioning. It should also be mentioned here, with regard to the advantages of using liquid nitrogen vaporization: since the leased oil-free air compressor systems can achieve oil-free drying and cleanliness (oil free, dew point < -70°C at 8.5 bar, dust removal precision of 0.01 μm), their quality is on par with that of nitrogen. However, the cost of the leasing option is much lower than that of liquid nitrogen vaporization; it is not restricted by the availability of liquid nitrogen in the surrounding area, and it is safer as there is no risk of suffocation. The advantage becomes more apparent as the required air volume increases. Of course, when it is used for purging large-diameter pipes, a pressure-holding pulse method is required, as the direct blowing approach with an open end cannot achieve the flow rate necessary for effective purging in such large pipes or systems. For debugging gas supplies, this leasing approach also has clear advantages; using liquid nitrogen for vaporization or large centrifuges to supply gas is clearly not economical. Furthermore, under certain specific conditions, the rental option for oil-free air compressors can also help reduce energy consumption and thereby lower operating costs. In some small-scale air separation facilities, such as those for electronic gases, some systems opt to use multiple centrifuges for gas production. During the phase of increasing production capacity, or when a customer’s production capacity declines, there may be an extra centrifuge available; in such cases, the load on the centrifuge is too low, yet its energy consumption remains high, resulting in wasted energy and damage to the centrifuge equipment. At this point, if a small oil-free screw compressor with an appropriate gas production capacity is rented to ensure an adequate supply of gas, it is possible to save on electricity costs. Supported by numerous practical cases from the electronics industry, the net cost savings after deducting rent from the energy costs saved can range from hundreds of thousands to several million. Of course, during the operation of all air compressors, in summer when there is insufficient air supply due to hot and humid conditions that result in thinner air, or during the period between the ordering and arrival of newly purchased equipment when there is a lack of air supply, or in cases of short-term shortages in air demand, renting air compressors is an excellent option. Given the high demands in the air separation industry regarding the quality of compressed air, the stability of equipment operation, and safety, rental plans generally involve the use of brands that are equivalent to or even superior to those used for proprietary equipment; this also imposes significant requirements on suppliers. The existence of reliable suppliers has also become a key factor and constraint in the selection and acceptance of this solution. The market already has several high-quality suppliers that can fully meet market demands, with device brands mainly being mainstream ones such as AC and IR. As a professional in this field, I truly hope that such new, more flexible solutions will be known to more colleagues in the industry, so that they have more good options when facing similar problems.