Can a pressure reducing valve be used to replace a gas-bearing turbine expander?
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An air separation unit, a device for producing liquid oxygen, is equipped with a gas-bearing turboexpander. Expansion end: The inlet features low-temperature air at -140°C and a pressure of around 0.5 MPa, while the outlet has low-temperature air (containing liquid) at a pressure of 0.15 MPa. Pressurization side: Both the inlet and outlet are connected to the atmosphere, and it primarily serves to control the speed and provide braking. I have some questions: 1. The energy at the pressure-boosting end is wasted; why isn’t it utilized? 2. The expander of this device is used to depressurize and cool low-temperature air at -140°C and 0.5 MPa. Can a low-temperature pressure relief valve be used as a substitute? Not only are investment and maintenance costs reduced, but the operational difficulty is also decreased?
You can ask your equipment engineer about this issue; there must be a reason for it to exist.
Hehe, I criticized such phenomena a few days ago, and sure enough it happened. First of all, you don’t understand the principles of the core equipment in air separation units; it is recommended that you familiarize yourself with the concepts of temperature, heat, and energy. Secondly, this integrated unit of the booster and the expander constitutes a whole for the conversion, recovery, and reuse of energy; if it’s as simple as you imagine, you can try to apply for a patent. If it’s really as you say, I can help you get in touch with potential markets. Regarding your question: 1. Your device is likely a small-scale fully liquid-based deep cryogenic air separation unit. If it’s convenient for you, you can share a diagram, and I can tell you what the pressurized gas generated by the compressor is used for. 2. Regarding whether to use a pressure valve instead of an expander, I recommend a book titled \"Oxygen Production Technology\"; it covers the concept of \"throttling effect\" as well as the principles behind expanders. One final piece of advice: if you don’t understand something, consult the masters and technicians around you. What you don’t understand is simply not understood, and one should not approach learning with the intention of finding faults in the design. Since you are still in the stage of “trying to understand something by touching it,” don’t draw conclusions blindly, as this can offend others. And one won’t receive help from others either, which is very unfavorable for learning*. Most of these phenomena involve young talents who have just entered society; when they go to the scene, they see that the majority of the people there are still \"masters\" who have not received a higher education. That’s true for them, but the equipment they use was created by highly educated intellectuals. Moreover, these users are also experts in using the equipment, and they cannot be underestimated; these observations are merely provided for reference.
Thank you for your answer. It was my first time dealing with the liquid oxygen project; I was a complete novice. I work in natural gas liquefaction; I’ve been in the LNG industry for over a decade. Due to differences in media, many designs vary ； So I said a lot of jargon; please forgive me, and thank you for your guidance. Our company currently has a project (in the planning stage) involving the development of a small liquid oxygen production unit for high-altitude areas, with a capacity of around 80 L/h. I’ve looked up some information, but I haven’t gained much from it. Do you have a process flow diagram for the liquid oxygen production device or any related materials? Please send me some; I would be very grateful. 174620505@qq.com.
The industries are related, all falling within the field of cryogenics. There are very few books on small-scale air separation. \"Answers to Questions on the Operation and Safety of Modern Small-Scale Air Separation Units\", \"Technology and Operating Principles of Modern Air Separation Equipment\", \"Oxygen Production Technology\". It can be found on this forum. For reference.
This post was last edited by CHANGBAISHI on 2020-7-17 at 16:08. This process is quite simple; it can be understood by referring to the process parameters specified in the instructions. The miniaturization of devices inevitably leads to certain energy losses, which is what is commonly referred to as the extraction efficiency. The two key points of this process are: 1. The cooling capacity generated by the expander, combined with the heat recovery in the heat exchanger, causes the air to condense and flow into the bottom of the tower ； 2. Due to the different pressure differences between the upper and lower towers, temperature differences arise, resulting in liquid evaporation on the upper side of the main cooler tower. The liquid from the main cooler is fed from the bottom of the tower to the top as a reflux stream; after distillation, the liquid that remains in the main cooler is the product, liquid oxygen. For reference.