Pressure issues in booster turbine expanders
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The expander currently being installed in our company has an inlet pressure of 0.38 MPA and an outlet pressure of 0.13 MPA； The intake pressure at the compression side is 0.735 MPa, while the exhaust pressure is 0.9 MPa. I’ve never understood how it’s possible to compress gas with a pressure of 0.38 MPa using a pressure of 0.735 MPa
The original poster should take a look at the principle of expanders, considering it from an energy perspective
The pressure at the expansion end drops from 0.38 MPA to 0.13 MPA after expansion; we can simply consider this as the pressure energy of the molecules being converted into kinetic energy through the nozzle, which in turn drives the impeller at the compression end to rotate. As a result of this rotation, the air is compressed from 0.735 MPA to 0.9 MPA. For more details, refer to the explanations on the principle of expanders, which provide a more thorough description
Actually, there’s no need to understand it that complicated: air enters at the expansion end in a radial direction and exits in an axial direction, with the pressure decreasing due to the expansion of the gas； At the pressurization end, gas enters axially and exits radially; the increase in gas pressure is achieved through centrifugal force.
May I ask the original poster what your process is like – how is it possible to have such expansion machine parameters?
May I ask what the compressed air from the expander, as mentioned by the original poster, is used for? Is it also air that flows through the expander? Are the expander and compressor coaxial? I work in pressure energy recovery, and I would like to discuss this with you. Thank you for your guidance