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Over-design factor should be applied upon the design case, max volumetric flowrate case can be different from max mass flowrate case.

Checking over-design criteria in a company standard, I found over-design factor for centrifugal compressor expressed as % of the volumetric flowrate while over-design factor for expander expressed as % of the mass flowrate. Why expander over-design is based on mass flowrate and not on volumetric...

@Johnny Pellin Thanks for your reply. Liquid is far away from boiling point, however is above flash point. Would you explain why no considers plan 52 or 53 for this service?

Good morning, I got an offer for a centrifugal pump for hot oil service. Operating temperature 300°C. Vendor propose seal plan API 01 with single mechanical seal. In my experience this service requires double seal with buffer fluid circulating through an air or water cooler for remove heat from...

@OpticControl Yes.

I used to determine compression number of stages basing on max discharge temperature, 150°C or whatever, what about cryogenic compressors where discharge temperature is always sub-ambient? Any criteria for assess if more than one stage is required?

How expander performance curves are affected by inlet guide vane position? I mean, I have design curves for this expander kg/h vs % isentropic and kg/h vs kW at different velocities, it is possible to obtain at least qualitatively curves at reduced IGV opening?

In one project specification is said that over stripping of amine shall be avoided as increased corrosion rate can occur if not enough H2S is left in lean amine solution to form iron sulphide passivating film on vessels and pipe walls. In one article from Amine Experts (Spooner & Sheilan - Iron...

In most of projects, isolation philosophy specify a vent valve between ball and globe valve in manual depressurization line, however sometimes there is not such valve. Can you explain purpose of such vent valve?

I have a centrifugal compressor with tandem dry gas seal. API 617 requires that maximum sealing pressure shall be at least equal to the settling-out pressure. What are the issues in restarting the compressor from settled out conditions if seal gas source has a pressure lower than settle out...

If liquid has vapor pressure higher than 1 atm at the min operating temperature I will not design the vessel for FV.

@btrueblood I got it, thank you for the explanation.

Dear, Thank you for your reply. There is only one GT with only one shaft. One section is called Gas Generator the other Power Turbine.

I’m study a machinery p&id of a GE PGT25 gas turbine. I noticed that there are two separate speed probes, one for gas generator rotor speed and one for power turbine rotor speed. Both probes given high velocity trip; gas generator rotor speed trip is set higher than power turbine rotor speed...

Hi, I'm looking for calculation methods and informative materials about torque -speed starting curve calculation. In particular I'm interested in screw compressor and the effect of equalized pressure start up via balancing line. Please share your expereiences, thank you.

Thank you for all the replies and in particular to Shvet for the articles. I cite from Perry: “…, unlike nozzles, the flow through a sharp-edged orifice continues to increase as the downstream pressure drops below that corresponding to the critical pressure ratio rc. This is due to an increase...

For do depressurization calculation with hysys, I’m accustomed to specify a coefficient of discharge of 0.62 for calculate the restriction orifice (RO) diameter needed for satisfy the design constrain, e.g. reach 6.9 barg in 15 min. This value of the coefficient of discharge is coherent with the...

Hi, I'm doing the control philosophy for a screw compressor equipped with API Plan 72/75, buffer gas is nitrogen. I notice that a flow switch high is specify in the inlet line to the seals. what is the reason for have this switch? What happens to the seals if the nitrogen flow is higher than...

Dear Sirs, Thanks for your valuable replies.

Hello! I have a doubt regarding on how to apply Annex C.2 of NACE ISO 15156-2 2009 Standard. For a gas free liquid system, the H2S partial pressure for assess the applicability of the Nace Standard, i.e. pH2S>0.05 psia, is calculated at a pressure corresponding to the bubble pressure at the...