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  1. marcsant

    Control valve vibration

    if the valve works with a max 80% aperture probably it has the capacity to pass the required flow (at operating conditions), in case of doubts, for two-phase flow (flashing liquid) there are specific (I mean adapted to control valves) models as HEM or HNE-DS (Diener and Schmidt) available in...
  2. marcsant

    Cv for manual piping globe valves

    the definition for Cv (number of U. S. gallons per minute of water that will pass through a given flow restriction with a pressure drop of one psi) is the same for control valves and (manually operated) globe valves, you can calculate Cv (from flow and dP) or estimate the value with a graph...
  3. marcsant

    Cv for manual piping globe valves

    to simulate a plant depressurization the procedure estimates the flow through valves, Ro and piping (from vessels to venting points) at each time step (numerical integration), if you have globe valves you should enter the (operating) value of Flow Coefficient (Cv) which depends from position of...
  4. marcsant

    Desuperheating in PRO/II

    PaoloPemi is correct, for a pure fluid you know inlet H, saturation conditions (final conditions) and latent hest, you can solve quickly, it's simple with a thermo library (as Prode) or Steam Tables etc. in your case the complexity arises from the fact that simulator doesn't expose the internal...
  5. marcsant

    The cost of well engineering software?

    if you run a small engineering company probably you should evaluate alternatives, software expenses incur upfront but benefits maybe realized over a long period... a realistic financial plan is essential if you wish to survive during the first years, nowadays many companies allow to rent a...
  6. marcsant

    Cloud point on hysys

    better to use a software which does true multi phase including a specific model for solids (wax) I have used Prode Properties but other tools (as those mentioned by MortenA) are available for this purpose....
  7. marcsant

    flash points of flammable mixtures (Prode Software)

    you may find some data in M.S. Thesis of Larson (Flash point Depression in Minimum Boiling Point Azeotropic Mixtures, 1998), the author reports a value of about 1 C (274 K) with seems in good agreement with the value predicted, hoping this helps, Marco
  8. marcsant

    Depressurisation time

    Orlando1326, nowadays most simulator include procedures to simulate a depressuring cycle, note that these can have limits, for example (in general) they don't consider non-equilibrium conditions as discussed in API (last revision), for these cases (where std. procedures don't work well) a...
  9. marcsant

    relief temperature

    I give a star to rense for suggesting rupture disks, while, as noted by don1980, they may be not suitable for liquid service due to high sensitivity to pressure spikes (a rupture disc may begin to open in less than 1 millisecond) with compressible fluids (gases) this problem is much less...
  10. marcsant

    Distillation column in Mathcad

    thanks for the *prompt* reply, I had lost that link.
  11. marcsant

    Distillation column in Mathcad

    does the Mathcad 15 extension include the Distillation Column (DCOL method) ? I get an error when calling this method
  12. marcsant

    Heat Exchanger Simulation in Excel

    I wish to create a (simplified) heat exchanger simulation (rigorous mass & heat balance + some preliminary design) in Excel with help of PRODE library, heating / cooling curves are calculated by solving a series of HPF() flash operations which I define as macros directly in Excel page, so far I...
  13. marcsant

    water dew point in natural gas

    I agree with PaoloPemi, the values in the database are good when there is no time or VLE data to regress, PRODE PROPERTIES includes a large number of BITs (compared to other simulators) so you have a good starting point in most cases. However one should not forget the limits, for example if you...
  14. marcsant

    vapor-solid flash to model a blow down

    we have full bore ESD valves for HP separators depressurization, no problems till now...
  15. marcsant

    Cubic Plus Association

    I know only a few sources of reliable VLE data, DECHEMA, DDB, (GPA) unfortunately these are not free.

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