Is 80 Pa Really a 'Huge' Pressure in Desalination Plants?

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Discussion Overview

The discussion centers around the pressure used in desalination plants, specifically questioning whether 80 Pa is considered a 'huge' pressure in the context of reverse osmosis. Participants explore the implications of pressure measurements in desalination processes, comparing Pascals to other units like bars and psi.

Discussion Character

  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant questions the claim that 80 Pa is a significant pressure, noting that it is less than 1 atm and comparing it to the pressure exerted by a human standing on a smaller area.
  • Another participant suggests that the relevant pressure figures for desalination are typically measured in bars, indicating that 1 atmosphere equals 1 bar, which implies that 80 Pa is low.
  • A participant expresses confusion about the claim made by a plant representative, who stated that 80 Pa is a 'huge' pressure, and seeks clarification on this point.
  • Some participants assert that the pressure required for reverse osmosis is generally in the hundreds of psi range, indicating that 80 Pa is indeed low and suggesting that pressures are usually in the order of MPa.
  • There is a suggestion that there may have been a misunderstanding regarding the units of measurement, with a reference to the link provided that indicates pressures are more commonly in the range of 80 bar rather than 80 Pa.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the characterization of 80 Pa as a 'huge' pressure. There are competing views regarding the appropriate pressure measurements for desalination, with some asserting that 80 Pa is low and others reflecting on the potential for unit confusion.

Contextual Notes

The discussion highlights potential limitations in understanding pressure units and their relevance in desalination processes, as well as the need for clarity in communication regarding technical specifications.

lioric
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I went to a desalination plant and the guy explaining reverse osmosis says that they force water through the membrane at a huge pressure of 80 pa

But I was wondering and that is less than 1atm. And it's like an 8kg placed on a 1 square meter space. I thing a 65kg human gives more pressure since the feet is smaller than 1 meter squared.
What am I missing here
 
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I know that. I'm asking this is 80 pa a lot of pressure? Cause that guy in the plant said so and I asked him if he's sure it's pa and he said " yes 80pa " and said it was a " huge" pressure.
 
The guy at the plant is incorrect. It takes pressure of the order of many hundreds of psi to force the water through a membrane depending on the salinity. 80 Pa is as you noted is pretty low. Think of the order of MPa.
 
gleem said:
The guy at the plant is incorrect. It takes pressure of the order of many hundreds of psi to force the water through a membrane depending on the salinity. 80 Pa is as you noted is pretty low. Think of the order of MPa.
Thank you
 
lioric said:
I know that. I'm asking this is 80 pa a lot of pressure? Cause that guy in the plant said so and I asked him if he's sure it's pa and he said " yes 80pa " and said it was a " huge" pressure.
As the link shows, the pressures used are in the range of 80 bar rather than 80 Pa.
So it may be than someone was confused about units.
 

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