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Recent content by DaveHasse

  1. DaveHasse

    High pressure air compression

    Oxygen in the air being compressed, about 15% v/v.
  2. DaveHasse

    High pressure air compression

    I am looking to make a high pressure air/CO2 stream. I have a mixing system which generates a 120 psi stream, which I then want to compress to 1500 psi. We do this with CO2/N2 now without issue, I was concerned that the O2 at this pressure would require special equipment. Does any one know...
  3. DaveHasse

    Net Driving force

    Net driving force refers to the driving force upstream minus driving force downstream. As an example: in a gas membrane, the driving force is a fugacity difference across the membrane. In most applications this can be calculated as a partial pressure difference, so if there is 60 psig of a...
  4. DaveHasse

    cylinder ring stands

    Debate going on whether or not cylinder ring stands (heavy rings that attach at the base of the cylinder) are appropriate for standard 44 liter cylinders. Does anyone have any documentation on this either way? Dave
  5. DaveHasse

    NMP color

    I believe NMP is clear to light yellow. It oxidizes to brownish colors. I talked to a QC engineer at one of the manufacturers, and he said the reaction is very strange. One of the products is NMS, but the coloring is very low concentration and proceeds less in air than in N2. (don't ask me...
  6. DaveHasse

    POMS- Polyoctylmethylsiloxane

    POMS material properties are largely a function of crosslinking and reaction kinetics. Without data on crosslink density, the other questions are moot. An intern here wrote a paper in part detailing POMS membranes with c3/c1 properties. He was from a French university, but other than that I...
  7. DaveHasse

    thermo haake extensional rheometer

    I saw a presentation of a thermo haake extensional rheometer, which extended a drop of fluid and measured the diameter with lazers, and then did calculations based on surface tensions. Has anyone any experience with these instruments
  8. DaveHasse

    Hydrogen limits

    I believe (rather than know) that oxygen activity is very pressure dependent, with the activity of 5 atm air almost equivilent to 1 atm O2. I would try this on the occupational health and safety board. Dave Hasse dave.hasse@Air Liquide.com
  9. DaveHasse

    Water removal membranes

    Second set of questions (#1 needs to be answered as well) high volume or low volume application? how dry is dry? can you afford some relative loss of O2? Dave Hasse
  10. DaveHasse

    Removing CO2 from a brathing loop

    Few if any commercial membranes will display a significant CO2/He selectivity, so I don't think a membrane will completely replace the soda lime. There has been work with possible commercialization on membrane contactors, with a membrane between the base and the gas stream. The system I have...
  11. DaveHasse

    hybrid membrane/absorption compact system

    Ok, I have a better idea now. I know that membrane hybrid systems are used in both configurations (adsorber/membrane, membrane/adsorber) Both can be set up to lower foot print. However, I work in R&D, so specific system design is not my forte. Most of the industrial gas companies (in this I...
  12. DaveHasse

    H2 recovery with membrane

    Some vendors for H2 separation. Air Liquide [my choice, OTOH they pay me to say that *-)] Air Products UOP these are all polymeric membranes and there are probably others. Last I checked, there are no fully commercialized ceramic membranes for gas separation. Metallic membranes are...
  13. DaveHasse

    hybrid membrane/absorption compact system

    I'm not sure about everyone else, but I don' think there is enough information here to help you. What do you mean by COMPACT? Is this a brand name? (as in Compact Membrane systems?) Or do you just want a smaller footprint? Is this for a lab scale process so you just want something small...
  14. DaveHasse

    H2 Membrane Separation Equipment Source?

    Oops, talked to my boss. He pointed out for a high value stream, such as this I assume, multistage membranes with recompression can give much higher purities and better recoveries. At which point I went "doh"... Dave
  15. DaveHasse

    H2 Membrane Separation Equipment Source?

    First issue, some gas membrane companies for H2 Air Liquide/Medal (my company) UOP Air Products (I'm pretty sure) This sounds like a small volume specialty application, so it might not be interesting on a size basis for a gas company. (in other words, not enough $$ to do the the design work...
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