Liquido Liquido-sector Del Fw.pdf

Liq-Liq Disengagement Tab (Horizontal Vapor-Liquid-Liquid)

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Liq-Liq Disengagement Tab (Horizontal Vapor-LiquidLiquid)

The Liq-Liq Disengagement Tab calculates the liquid-liquid disengagement performance of the separator. The calculations and applicable fields depend upon the configuration (i.e. boot, weir, baffle or none). Three conditions indicate whether or not disengagement is satisfied: 1. The calculated particle diameter should be less than the target particle diameter. 2. The rising/settling velocity should be less than 10 in/min (254 mm/min). 3. The dispersed phase residence time (Misc tab) should be less than the corresponding continuous phase residence time. In general, if one of the three criteria above is not satisfied all 3 criteria are not satisfied. However, it is possible to meet the first condition and not meet the second and third conditions. This is due to the fact that the particle diameter calculation is not limited to rising/settling velocities greater than 10 in/min (254 mm/min). If any of the three criteria are not met then disengagement is not satisfied and the vessel size should be increased. The following table lists some typical particle diameters for hydrocarbon/water service:

mk:@MSITStore:C:\Program%20Files%20(x86)\VESA%20R2\vesa.chm::/Horizonta... 04/04/2019

Liq-Liq Disengagement Tab (Horizontal Vapor-Liquid-Liquid)

125 micron

35° API or lighter hydrocarbon

90 micron

heavier than 35° API hydrocarbon

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35° API is equivalent to a specific gravity of 0.8498 (53.0 lb/ft³ or 849.4 kg/m³) . Consult the Vertical Particle Velocity Calculation and Disengagement topics for additional information on these calculations. The From Reference Level and To Reference Level drop-down fields are used to specify the disengagement path that the calculation is based on. Consult the Overview topic for additional details. The Upper Reference Level and Lower Reference Level drop-down fields are used to determine the cross-sectional area that the Main Vessel Velocity and Main Vessel Reynolds No. fields are based on. For example, if the light continuous phase upper reference level is set to NLL and the lower reference level is set to NIL then the cross-section area would be based on the shaded region in the diagram below:

Since the heavy continuous phase always extends to the bottom of the vessel, you only need to specify the upper reference level. Remarks: Rising/Settling velocity, Reynolds number and drag coefficient are based on the calculated particle diameter and not the target particle diameter.

A design factor of 2 is used to calculate the boot diameter. This means that the allowable boot velocity is one half the rising velocity of the light liquid dispersed phase.

mk:@MSITStore:C:\Program%20Files%20(x86)\VESA%20R2\vesa.chm::/Horizonta... 04/04/2019