What are the differences between various gas compressors?

The designs are different, and the process parameters vary

It’s the same with poker – you might play Dou Dizhu, but you don’t necessarily play Zha Jin Hua or Chuan Huo Jiao

It is related to the physical properties of the medium; especially for gases, the physical properties change significantly upon compression, and this has a certain impact. For example, with the same medium and the same voltage boost, but different temperature changes.

Firstly, for centrifuges, although their basic structure is the same, their most crucial core component—the impeller—is completely different in each operating condition. Next, we need to talk about the development, design, and mass production of industrial equipment. The design of impellers is not something that can be decided casually; simply creating one that meets the requirements of the operational conditions is not sufficient. In the fierce competition among top-brand manufacturers, impeller efficiency is the most important criterion for evaluation, and developing an efficient impeller model requires significant investment. To go deeper, the development of a basic impeller model stage is not something that can be achieved simply; it requires design, calculation, verification, testing, adjustments, and application validation in order to create an impeller model with a wide range of applicability and excellent performance. However, in product manufacturing, proven impeller models are used to make adjustments to suit the operating conditions, in order to meet the requirements for rapid design, production, and manufacturing. After all, it takes just over a year from winning a contract to delivering the product – there’s no time to develop and verify new models slowly Finally, we come to verification, which is what is commonly referred to as the industry threshold. In the contracts for the key units of almost all petrochemical projects, there is a requirement: experience of successful operation under two similar operating conditions for more than three years. Why? Regarding the development of centrifuge impellers, it’s not the case that what you calculate will necessarily be correct; current physical calculation formulas cannot fully reflect the actual conditions of an impeller. Impellers designed using these formulas must undergo testing, and the formulas need to be continuously revised based on the data obtained from those tests in order to arrive at a basic model and corresponding validation formulas. Even that isn’t enough; for such important equipment, performance is the best proof, which is why manufacturers are required to have experience in successful operation. What if it’s in a completely new operating condition? For performance testing, an inert gas with a density similar to that of the process gas is used, and comprehensive performance tests are carried out; these tests are quite expensive!

The current approach to manufacturing centrifugal compressors is: surveying, recalculation, and manufacturing. Surveying and mapping mainly refers to existing foreign equipment in operation; recalculation involves using advanced compressor design software to process the data from the surveying machines; manufacturing refers to the processing capabilities of factories. As long as the above three requirements are met, any compressor can be used.

Those who need calculations in this area can send them over; I’ll do the calculations for you free of charge!

Thank you! Actually, I also know that different gases have different physical and thermodynamic properties. What I actually want to ask is: for these different media, what are the biggest differences in terms of the compressor’s structure, materials, sealing, hydraulic model, or pneumatic model? Especially, what should we pay attention to when making the selection?

If it’s not the manufacturer, purely from the user’s perspective, it is impossible to determine which impeller model is the most suitable. Whether the most appropriate model can be selected depends on two factors: first, optimal performance. Under the same operating conditions, whose efficiency is the highest? Who has a wider range of operations? Second, it has the best performance. In other words, who achieves the best results under similar working conditions? It is important to note that sometimes manufacturers compare similar operating conditions from different industries; we generally do not allow this, as even if the molar amounts are the same, the media in question can still differ significantly. The structure is basically the same; the material requirements are detailed in Appendix D of API 617, and the sealing is carried out in accordance with Section 4 of API 614. Above

Thank you. Actually, I encountered a manufacturer whose compressors are used for compressing natural gas. When I asked them if they could produce units for compressing air, they said they couldn’t do that. I just want to know why it can’t be done. Logically, natural gas is more dangerous than air, and the structure of such units is also more complex – so why isn’t it possible to do it?