Oil-free lubrication for piston compressors
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Our factory is a fertilizer plant that produces urea using a fixed-bed gas generation process. The nitrogen and hydrogen compressors in use here are lubricated with oil via high-pressure oil injectors; the service life of the piston rings in the high-pressure section is generally around 6 months. We would like to know which factories use oil-free lubrication for their nitrogen and hydrogen compressors How is it performing? What is the material of the piston rings? How long is its lifespan? We want to take a look; if possible, we’d also like to make some changes.
Typical oxygen compressors are oil-free lubricated, and the materials used for piston rings are standardized, with relevant technical specifications available. You can call the manufacturer for consultation
The piston rings in the high-pressure section have been in use for six months, and their service life is quite good. At my previous employer (Lanzhou Yuandong Fertilizer Co., Ltd.), the oil-free lubricated piston rings used in the fifth and sixth stages of the 4M20 compressors for nitrogen and hydrogen were manufactured by Shanghai Zhenjie Machinery Factory. These rings performed well; a layer of tetrafluoride was applied as a coating on the surface of the copper, and the cylinder liners also had such a coating. Often, before the compressors reached the point where they needed to be replaced, management would order their replacement anyway. Shanghai Zhenjie Machinery Factory has changed its name now; I forgot what it is. However, the prices are quite high.
I’ve also heard that copper piston rings are used in combination with PTFE, but it’s the first time I’ve heard that the cylinder liners need to be pre-coated with PTFE as well. Moreover, why did your management replace the piston rings before the items reached the point where replacement was necessary? Are there any manufacturers using it in North China? Could everyone give some guidance?