Engineering-Stream - Software for Engineering Applications

Three Phase Separator Sizing - Horizontal (Simpler Version) - Beta

Step 1 - Input Process Conditions

Operating Pressure, Pg    psig
Atmospheric pressure, Pa    psia
Operating Temperature, Tf    deg.F
Mass flow rate of gas, Wv    lb/hr
Molecular Weight of gas, MW    lb/lbmol
Compressibility Factor, Z
Viscosity of gas, mu_g    cP
Mass flow rate of light liquid, W_LL    lb/hr
Density of light liquid, rho_LL    lb/ft3
Viscosity of light liquid, mu_LL    cP
Mass flow rate of heavy liquid, W_HL    lb/hr
Density of heavy liquid, rho_HL    lb/ft3
Viscosity of heavy liquid, mu_HL    cP
Required Hold Up Time of Light Liquid (LLL to NLL), tH    min
Required Surge Time of Light Liquid (NLL to HLL), tS    min
Calculated density of gas, rho_V    lb/ft3
Actual volumetric flow rate of gas, Q_V    ft3/min
Mixed Liquids density, rho_L    lb/ft3
Mixture fluid density, rho_m    lb/ft3

Step 3 - Set Levels and heights

Selected inside diameter of vessel (in), Di    in
Selected inside diameter of vessel (ft), Di_ft    ft
Recommended vapor space, Hv_calc (Larger of 0.2*Di or 2 ft (24 in))    in
Selected Vapor space, Hv    in
Verify1 (Hv >= Hv_calc) :
Calculated Low liquid level in light liquid compartment, H_LLL_calc    in
Selected Low liquid level in light liquid compartment, H_LLL    in
Verify2 (H_LLL >= H_LLL_calc) :
Weir height (min 2 ft or 24 in), Hw    in
Minimum Length of the light liquid compartment to accomodate Holdup / Surge, L2_calc    ft
Selected length of the light liquid compartment to accomodate Holdup / Surge, L2    ft
Verify3 (L2 >= L2_calc) :
Minimum Inlet Nozzle Size, dN_calc    in
Selected inlet nozzle size, dN    in
Verify4 (dN >= dN_calc) :
Heavy Liquid height upstream of weir, H_HL    in
Light Liquid height upstream of weir, H_LL    in
Stoke's law terminal velocity constant (eg., 0.163 or 0.333 - see below), ks    (in/min)(cP)/(lb/ft3)
Settling velocity of the heavy liquid out of the light liquid, U_HL    (in/min)
Rising velocity of the light liquid out of the heavy liquid, U_LH    (in/min)
Calculated Length of the mixed liquid compartment upstream of weir, L1_calc    ft
Selected length of the mixed liquid compartment upstream of weir, L1    ft
Verify5 (L1 >= L1_calc) :
Setting time of the heavy liquid out of the light phase, t_HL    min
Setting time of the light liquid out of the heavy phase, t_LH    min
Residence time of the light liquids, theta_LL    min
Residence time of the heavy liquids, theta_HL    min
Verify6 (theta_HL >= t_LH) :
Verify7 (theta_LL >= t_HL) :
Selected Length of the vessel, L    ft
Liquid dropout time, phi    s
Actual vapour velocity, Uva    ft/s
Minimum length required for vapour-liquid disengagement, Lvl    ft
Verify8 (L >= Lvl) :

Step 4 - Final Design

Diameter of the vessel and Feed Nozzle

Selected inside diameter, Di    in
Selected inside diameter, Di_ft    ft
Length of the mixed liquid compartment upstream of weir, L1    ft
Length of the light liquid compartment to accomodate Holdup / Surge, L2    ft
Total Length of the vessel, L    ft
Selected Feed nozzle diameter, dN    in

Levels and heights

Vapor space, Hv    in
Weir height, Hw    in
Heavy Liquid height upstream of weir, H_HL    in
Light Liquid height upstream of weir, H_LL    in
Low liquid level in light liquid compartment, H_LLL    in

Retention Volume and Retention Time

Height of the Heavy Liquid Level (Vessel Bottom to Liquid-Liquid Interface) U/S of weir, H_HL    in
Retention Volume (Heavy Liquids) (Bessel Bottom to Liquid-Liquid Interface) U/S of weir, Vr1    ft3
Retention time (Heavy Liquids) U/S of weir, tr1    min
Height of the Light Liquid Level (Liquid-Liquid Interface to Weir) U/S of weir, H_LL    in
Retention Volume (Light Liquids) (Liquid-Liquid Interface to Weir) U/S of weir, Vr2    ft3
Retention time (Light Liquids) U/S of weir, tr2    min
Height of the normal liquid level (NLL) D/S of weir, from vessel bottom, H_NLL    in
Retention Volume (Light Liquids) (vessel bottom to NLL) D/S of weir, Vr3    ft3
Retention time (Light Liquids) D/S of weir, tr3    min

Help

General Notes:

Note: Refer to the "Terms and Conditions" in the 'About' section before using the software.

1) Three Phase Vertical Separator Sizing is a software program that can be used to size 3 phase vertical liquid / liquid / vapour (gas) separators.

2) The procedure is a simplified version based on Chapter 7 - Separation Equipment, presented in GPSA / industry standards.

3) The separator in consideration is assumed to be equipped with a mist extractor. The software is not designed and hence should not be used for other types such as vane type separators. Heads on either ends of the shell are not considered for volume calculations such as surge volumes, retention volumes etc., for the sake of simplicity.

4) The user needs to select / fill in relevant input data under Step1' and then click 'Calculate1' button so the program calculates the relevant parameters. The user then needs to fill in relevant data under 'Step2' and click 'Calculate2' button and so on.The procedure needs to be followed sequentially. If previous cells are not calculated, enter values on all white cells above the particular cell and click the button multiple times sequentially. When an update to any input is made, the procedure needs to be followed sequentially again by clicking the buttons in sequence, so the calculations are updated under each step.

5) Typical control surge times (LLL to HLL) for liquids for various types of separator vessels are as below.
Compressor Drum : 2 minutes
Flash Drum : 2 - 5 minutes
Reflux Drum: 5 minutes on product plus reflux
Surge Drum upstream of a Tower: 5 - 10 minutes
Surge Drum upstream of a Fired heat: 10 minutes
Net Product to Storage: 5 minutes
Refrigeration Accumulator: 5 minutes, or based on system or storage requirements
Refrigeration Economizer: 3 minutes
Heat Medium Surge Drum: Maximum liquid expansion, based on 25% to 75% full

6) For Liquid-liquid separation , ks = 0.163 for droplet diameter of 89 microns, ks = 0.333 for droplet diameter of 127 microns.

7) Typical retention times (empty to NLL) for liquids for various types of separator vessels as as below.
Amine Flash Drum : 5 - 10 minutes, depending on presence of hydrocarbons
Glycol Flash Drum : 10 - 20 minutes, depending on presence of hydrocarbons
Cold Separator: Gas / NGL / Ethylene Glycol : 15 - 30 minutes, depending on internals

8) Suggested mixed phase velocity head range for the inlet nozzle, J_Limit
Diffuser distributor: 4,000 - 6,000 max lb/ft • sec2
No inlet distributor : 650 - 1,500 max lb/ft • sec²
Inlet half pipe or elbow distributor: 1,000 - 2,500 max lb/ft • sec2
V-baffle or other simple invert diverter designs: 1,000 - 2,500 max lb/ft • sec2
Cyclonic inlet device: upto 10,000 lb/ft • sec2
Suggested outlet velocity head range, J_Limit 3000 - 3600 max lb/ft • sec2

9) All numbers need to be entered without commas. Empty boxes, non-numerical values are not allowed where numbers are expected.

10) Enter data in Cells with white background. Cells with gray background show calculated values.

11) Please provide any constructive feedback so we can improve the quality of the software.