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  1. Jobst

    Using hot cooling tower water for heating

    I remember seeing something like this at a large milk processing plant. There was demand for both heat and cooling, at relatively mild temperatures, and someone had worked out that the duty of each was about the same, but only when averaged over a few hours. So they installed a huge tank that...
  2. Jobst

    Design of calming baffle in gas-liquid separator

    I mean something like shown here, labelled as "perforated distribution baffle".
  3. Jobst

    Design of calming baffle in gas-liquid separator

    Hello all, Can anybody point me to any references for design of calming/stilling baffles in two phase separators? My particular application is for a horizontal separator, to even out the flow profile in the liquid directly beneath the inlet device, before it flows into some internals. Mainly...
  4. Jobst

    Liquid pressure drop across thick, multi-hole orifice plate

    Thanks everybody for your comments. It's been a while since I've had to do more than very standard hydraulics, appreciate the discussion. I've set up some calculations treating the orifices as individual "pipes". The calculation has three components: entrance loss, frictional loss along the...
  5. Jobst

    Liquid pressure drop across thick, multi-hole orifice plate

    Hole spacing is on the order of 5-20x hole diameter. There's a bunch of plate permutations to be tested. Flow and dP data for existing setup is ok (and close enough to what I calculate), but plate is much thinner. Correlations I'm using so far don't account for plate thickness/hole length...
  6. Jobst

    Liquid pressure drop across thick, multi-hole orifice plate

    Similar - though my plate is flush with the top of the vessel. And I have a lot more holes in the plate!
  7. Jobst

    Liquid pressure drop across thick, multi-hole orifice plate

    The orifice plate is actually discharging into a pressure-controlled vessel filled with gas, so not your typical pipe flow situation. Flow through the plate is controlled, I need to make some changes to the plate and verify if the pump will still be capable of the job across the flows needed.
  8. Jobst

    Liquid pressure drop across thick, multi-hole orifice plate

    Hi All, I have an issue where I'm trying to estimate the pressure drop of a liquid through a multi-hole orifice plate. I know how to do this for a "thin" plate, i.e. thickness/hole diameter <= ~1, but am having trouble finding methods for a thick plate where the aspect ratio of the holes is...
  9. Jobst

    LOPA question

    I would contrast this with the case where a BPCS loop is managing something 100% of the time during the year: the probability of that failing, per CCPS, is 0.1/year. Now, what is different about the loop in question, that it is only operated for a few hours (or tens of hours) in a year, but has...
  10. Jobst

    Powder dosing into a pressurized vessel

    What's stopping you stretching some kind of sock filter over the top of your funnel?
  11. Jobst

    Powder dosing into a pressurized vessel

    Can you make a slurry out of the powder beforehand (or pre-dissolve it in some substance) before adding to the tank? Or encapsulate the powder in some material soluble in, but not harmful to the tank's contents? Any feed lines or exterior circulation loops where you could add a venturi feeder...
  12. Jobst

    Gender Based Hiring Quotas in Australia

    That sort of boils down to whether people are aiming for "equality of opportunity" or "equality of outcome". I've noticed that certain groups pay a lot of lip service about providing the former, while ignoring or refusing to believe that a lot of systemic biases still exist that prevents the...
  13. Jobst

    When distributor between beds needed and when not?

    If the column is working as intended at design point is there really a problem with not having a redistributor? I would investigate, document, and file it away for when it is actually causing a problem.
  14. Jobst

    Trace components and autoignition temperature

    CS2 is on that list at 90°C. Unfortunately Perry's doesn't have any discussion on treating mixtures of gases with a single combined autoignition temperature. You're right though, in that most of the gases in that table are in a similar range of temperatures, and if I had a mixture of a few of...
  15. Jobst

    Trace components and autoignition temperature

    Hi All, Can anyone point me in the right direction for dealing with trace components in a gas mixture, and whether these need to be taken into account when determining temperature code for equipment? E.g. I have a gas where the bulk components would warrant T2 (<300 °C). However, there's <100...
  16. Jobst

    Reverse Osmosis for Bio-ethanol production

    Some beer brewing companies use reverse osmosis to make low alcohol beer (water and ethanol pass through membrane, with a higher concentration of ethanol in the permate than in the original beer) but this is very energy intensive and the concentration factor is very low.
  17. Jobst

    Specifying gas valves for wide duty range

    Thank you both for your comments. 2x equal percentage valves cover the range without going outside the 15-80% opening window so I'm happy about that. Doing a bit more analysis (part a of gerhardl's suggestions) shows the duty is not as bad as I first thought, as the downstream operation is...
  18. Jobst

    Specifying gas valves for wide duty range

    Hello Everybody, I have a case where a valve is needed for regulating the pressure inside a process. The issue is that the pressure setpoint(and flow required to maintain this pressure) varies quite a lot. The valve(s) is installed downstream of the process, and the process itself has inlet...
  19. Jobst

    milk powder viscosity

    Depends on the powder formulation. When I worked at a powder plant viscosity of reconstituted solution varied dramatically between grades.
  20. Jobst

    Small scale sulfur removal

    Thanks for responses. I was indeed worried about all the CO2 -- maintaining alkalinity in a solution in contact with that stream seems like a no-go. Solid formation in a packed tower is definitely not the design intent! The stream isn't actually syngas (rather, it hasn't originated in a place...

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