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  1. hirschaplin

    Definition of various gas mixture characteristics

    Maybe one way to do it, is to flagg each component with AI against these different categories and a chemical database. If a single gas is flagged as "toxic" and then an entered gas mixture includes this component, regardless of vol%, this mixture gets flagged as toxic since a toxic component is...
  2. hirschaplin

    Definition of various gas mixture characteristics

    Well, as I said - I am looking for official definitions of these characteristics to... define them! Is inflammable and flammable the same thing? I don't think so, in many data sheets it is differentiated but without a clear definition, it is not easy to argue either way... I can probably not...
  3. hirschaplin

    Definition of various gas mixture characteristics

    Sometimes a gas mixture is described as inert, flammable, lethal, explosive, corrosive, inflammable, sour, toxic or oxidizing. Perhaps even more descriptions exist... I am working on a system where gas mixtures are regularly entered and I want to find a method to automatically, via python...
  4. hirschaplin

    Roots type blower with high vibrations

    @georgeverghese there is only a recycle line with a FCV to control the flow to downstream operations. But this line is not fully sized intentionally to handle the full flow, i.e. 100% recycle. Seems like they forgot about testing purposes. :-) @pierreick That reference is a joke and it...
  5. hirschaplin

    Roots type blower with high vibrations

    Can the pulsations create a pressure thrust motion in the unrestrained expansion joints that acts on the blower flanges?
  6. hirschaplin

    Roots type blower with high vibrations

    We have continued to measure the spectrum at different positions on and around the blower. It is clear that all clear peaks are att 88,5 Hz (4 X RPM) which is the pocket passing frequency (rpm*4/60=1327.5*4/60=88,5 Hz). Meaning pressure pulsations. The readings at 4 X RPM occur most clear on...
  7. hirschaplin

    Roots type blower with high vibrations

    Continue to run now with Hydrogen (88% H2 and 12% N2). Expansion joints are tweaked a bit, seems like no difference... Here are some logs from tonight playing with rpms and pressure settings: Unfortunately the system doesn't have a proper recycle line, hence it is a bit difficult to set the...
  8. hirschaplin

    Roots type blower with high vibrations

    Flexible 500 mm spacer coupling between motor and blower. I think we might be on to something. We stopped the test cycle last night to perform hot alignment and once the bolts holding the blowers 4 foots was loosened, the blower was moved sideways by itself by the expansion joint. Inlet and...
  9. hirschaplin

    Roots type blower with high vibrations

    Hello, Have some problems with a roots blower. Twelve inch gears, 762 mm long bi-lobes. Horizontal gas flow. Operating with a 80% hydrogen mixture. Inlet about 0,6 barg / 30 deg C Outlet about 1 barg / <70 deg C Machine max. allowable speed as per the OEM is 1800 rpm. The blower is driven by...
  10. hirschaplin

    Is this a bearing load diagram and how to read it

    Hello, I came across something that I believe is a bearing load diagram, if not please correct me: How shall I read it and can someone explain the meaning of the numbers pointing in different directions?
  11. hirschaplin

    Approach to predict the noise level of a rotary machine

    Hello, If you have a range of various models of roots blowers, what is the path to be able to predict sound level at various operating points for each machine in the range? Is full testing and noise measuring of each rpm and pressure point the only way to go or is it possible to determine the...
  12. hirschaplin

    Approach to predict noise level and how to communicate it

    Hello, Over the years, I have participated in a number of tenders for the supply of rotating machinery to various EPC contractors pretty much all over the world. Nowadays, machinery noise level seems more important than ever. I guess mainly due to more stringent regulatory requirements pushing...
  13. hirschaplin

    The jungle of Specific Heat Capacities and how to get it right

    Yeah rocket science. [glasses] You don't have a paper to determine the critical temperature, critical pressure and acentric factor for a gas mixture?
  14. hirschaplin

    The jungle of Specific Heat Capacities and how to get it right

    Where do I find pseudo components and what is that?
  15. hirschaplin

    The jungle of Specific Heat Capacities and how to get it right

    @pierreick I couldn't resist to start look into https://cheguide.com/cubic_eos.html Very good link. A question, can I use this method to find Z for a mix gas? If yes, how can I determine the critical temperature, critical pressure and accentric factor of the mix gas? Is it in a similar way as...
  16. hirschaplin

    The jungle of Specific Heat Capacities and how to get it right

    Good morning, This is becoming to abstract for my level of understanding. Mainly I need K-value, Molecular weight and Z compressibility factor as input variables to my other calculations. As I already have the Z compressibility factor in my volume/mass flow calculations, I am unsure of if/why...
  17. hirschaplin

    The jungle of Specific Heat Capacities and how to get it right

    @Pierreick you are wearing me down :-) I have understood that my calculations are based on the ideal gas law. Is 1 bar A and 20 C the definition of all ideal gases or why are you saying that this is the assumption of my calculations? I am confused because of this T in the Cp equation: I...
  18. hirschaplin

    The jungle of Specific Heat Capacities and how to get it right

    @Pierreick I have a parameter to adjust the temperature, T is a variable in the equation I use. I can't adjust the pressure with my current equation. When you say 1 bar is that 1 bar absolute pressure? How or why do you know it is at 1 bar? I made this comparison of Methane between ChemCAD...
  19. hirschaplin

    The jungle of Specific Heat Capacities and how to get it right

    @IRstuff, thanks! Ok guys, tonight there is a smile on my face. Finally the Cp, Cv and K calculations work as intended: Now I just need to adjust the few lines which requires eqn. 2 and 3. Then I should have fairly good values for Cp, Cv and K for all 231 substances in my database. Which...
  20. hirschaplin

    The jungle of Specific Heat Capacities and how to get it right

    @pierreick you are my saver like always. 35,9699614184067/16,0426=2,24 kJ/kg K which match very well with the value in my reference table that is 2,22 kJ/kg K. @MintJulep that seems like a sweet program which I maybe can use for verification purposes. @shvet I already have a working method...

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