EXAMPLE 1: SIZE A 2-PHASE VERTICAL SEPARATOR JOB SPECIFICATIONS: GAS Flow, MMSCFD MW Temp, deg F Pres, PSIG compressibility factor viscosity, cp ATM PRES PSIA LIQUID Flow, BPD specific gravity minimum level, in. SEPARATION remove drops >__micron Flow Character (slug, free, entrained, mist) APPLICATION TYPE: TYPE OF VESSEL: VESSEL CONFIGURATION: MIST EXTRACTOR: CALCULATIONS: 1. Calculate design specification information pg = (P+Pa)(MW) 10.73*(T+460)*(z) pl = 62.4(sp. gr.) Dp= 0.00003937(micron)/12 m=MMSCFD(1e6)(MW) 379.4(24)(3600) Qa=m/pg Ql=42W/7.481/86400 Qm=Qa+Ql pm=(pl*Ql+pg*Qg)/Qm 2. Calculate minimum diameter for gas capacity Method 1a: Equation 10 and Figure 8 CDRe^2 (Eq. 10)
12 22 120 600 0.9 0.012
(shaded cells require input)
14.7 50 0.5 8 150 free liquid intercept knockout vertical no
2.41 lb/cu ft 31.20 lb/cu ft 0.000492 ft 8.05 lb/sec 3.34 0.0032 3.34 2.44
acfs cu ft/sec cu ft/sec lb/cu ft
5464.84
CD from Fig 8
1.70
Vt = (4gDp (rl-rg)/3CDrg)^0.5
0.38 ft/sec
Minimum dia.= 12*(TZQg/2.4Vt(P+Pa))^0.5
39.9 in
2
Method 1b: Stokes' Law, Newton's Law, Intermediate Stokes' Law Re = 1488(DpVtrg)/m 2
Vt = 1488gDp (rl-rg)/18m Minimum dia.= 12*(TZQg/2.4Vt(P+Pa))^0.5
3.5 ft
Stokes' Law Not Applicable 227.85 1.546 ft/sec 19.9 in
2 ft
Newton's Law Re = 1488(DpVtrg)/m Vt = 1.74(gDp(rl-rg)/rg)^0.5
Newton's Law Not Applicable 111.43 0.756 ft/sec
Minimum dia.= 12*(TZQg/2.4Vt(P+Pa))^0.5
28.4 in
Intermediate Range - Iteration Trial No. Assume CD
1 0.34
Vt = (4gDp(rl-rg)/3CDrg)^0.5
2.5 ft
2 0.80
Intermediate Range Is Applicable 3 4 5 0.96 1.00 1.01
0.86
0.56
0.51
0.50
0.50
126.82
82.90
75.51
73.84
73.43
Calculated CD
0.80
0.96
1.00
1.01
1.02
Minimum dia.= 12*(TZQg/2.4Vt(P+Pa))^0.5
35.0 in
Re = 1488(DpVtrg)/m
3 ft
3. Calculate vessel liquid capacity requirements Method 3a: Arnold-Stewart Vessel Diameter, dv Residence Time, t Liquid Height, h Lss = (h+76)/12 Lss = (h + dv + 40)/12 Vessel height S/S
36 3 0.965 6.4 6.4 6.4
L/D
2.167
Method 3b: Svrcek-Monnery Vessel Diameter hold up time, t1 hold up volume, Vh=60Ql*t1 surge time, t2 surge volume, Vs=60Ql*t2 low liquid level, Hlll norm liq level, Hh = Hnll-Hlll = 4*12Vh/pDv^2 high liquid level, Hs = Hhll-Hnll = 4*12Vs/pDv^2 inlet nozzle, dn=(4Qm/(p*60/pm^0.5))^0.5*12 centerline inlet, Hlin-Hhll=12+dn disengagement, Hd-Hlin=36+dn/2 mist extractor, Hme Vessel height, Ht=Hlll+Hnll+Hlin+Hdme
3 3 0.585 3 0.585 8 0.993 0.993 3.99 15.99 38.00 0.00 63.98
L/D
1.833
in min in ft ft ft
6.5 ft
ft min cu ft min cu ft in in in in in in in in
5.5 ft
Method 3c. GPSA Engineering Databook Vessel Diameter Mist Extractor Depth Inlet Nozzle Diameter
36 in 0 in 4 in
Mist Extractor Btm to Top Seam Disengagement Area = Greater of Dv or 24" inlet nozzle area, 2*(4Qm/(p*60/pm^0.5))^0.5*12 Level Gauge to Hi-Level SD (12-inch Min.) Level Gauge & Controller (12-inch Min.) Lo-Level SD to Level Gauge (12-inch Min.) Minimum Level
0 36 8 12 12 12 8
Vessel height S/S
88 in
L/D
2.500
in in in in in in in
Time 36.3 min 36.3 min 36.3 min
7.5 ft
Not Applicable
ange Is Applicable 6 1.02 0.50 73.33 1.02
EXAMPLE 2: COMPARE 4 METHODS FOR DETERMINING DIAMETER JOB SPECIFICATIONS: GAS Flow, MMSCFD MW Temp, deg F Pres, PSIG compressibility factor viscosity, cp ATM PRES PSIA LIQUID Flow, BPD specific gravity SEPARATION remove drops >__micron Flow Character (slug, free, entrained, mist) APPLICATION TYPE: TYPE OF VESSEL: VESSEL CONFIGURATION: MIST EXTRACTOR: CALCULATIONS: 1. Calculate design specification information pg = (P+Pa)(MW) 10.73*(T+460)*(z) pl = 62.4(sp. gr.) Dp= 0.00003937(micron)/12 m=MMSCFD(1e6)(MW) 379.4(24)(3600) Qa=m/pg Ql=42W/7.481/86400 Qm=Qa+Ql pm=(pl*Ql+pg*Qg)/Qm 2. Calculate minimum diameter for gas capacity Method 1: Equation 10 and Figure 8 CDRe^2 (Eq. 10)
12 22 120 600 0.9 0.012
(shaded cells require input)
14.7 50 0.5 150 free liquid intercept knockout vertical no
2.41 lb/cu ft 31.20 lb/cu ft 0.000492 ft 8.05 lb/sec 3.34 0.0032 3.34 2.44
acfs cu ft/sec cu ft/sec lb/cu ft
5464.84
CD from Fig 8
1.30
Vt = (4gDp (rl-rg)/3CDrg)^0.5
0.44 ft/sec
Minimum dia.= 12*(TZQg/2.4Vt(P+Pa))^0.5
37.3 in
2
Method 2: Souders-Brown with and without demister With Demister K (From Table) Vt=K((pl-pg)/pg)^0.5 Minimum dia.= 12*(TZQg/2.4Vt(P+Pa))^0.5 Without Demister K (From Table) Vt=K((pl-pg)/pg)^0.5
3.5 ft
0.18 0.622 ft/sec 31.4 in 0.09 0.311 ft/sec
3 ft
Minimum dia.= 12*(TZQg/2.4Vt(P+Pa))^0.5 Method 3: Newton's Law Re = 1488(DpVtrg)/m Vt = 1.74(gDp(rl-rg)/rg)^0.5 Minimum dia.= 12*(TZQg/2.4Vt(P+Pa))^0.5 Method 4: Stokes' Law Re = 1488(DpVtrg)/m Vt = 1488gDp2(rl-rg)/18m
44.4 in
4 ft Newton's Law Not Applicable
111.43 0.756 ft/sec 28.4 in
2.5 ft Stokes' Law Not Applicable
227.85 1.546 ft/sec
Minimum dia.= 12*(TZQg/2.4Vt(P+Pa))^0.5
19.9 in
Intermediate Range - Iteration Trial No. Assume CD
1 0.34
2 0.80
Vt = (4gDp(rl-rg)/3CDrg)^0.5
0.86
0.56
0.51
0.50
126.82
82.90
75.51
73.84
Calculated CD
0.80
0.96
1.00
1.01
Minimum dia.= 12*(TZQg/2.4Vt(P+Pa))^0.5
35.0 in
Re = 1488(DpVtrg)/m
2 ft Intermediate Range Is Applicable 3 4 0.96 1.00
3 ft
d cells require input)
n's Law Not Applicable
' Law Not Applicable
ediate Range Is Applicable 5 6 1.01 1.02 0.50
0.50
73.43
73.33
1.02
1.02
EXAMPLE 3: EXISTING SEPARATOR JOB SPECIFICATIONS: GAS Flow, MMSCFD MW Temp, deg F Pres, PSIG compressibility factor viscosity, cp ATM PRES PSIA LIQUID Flow, BPD specific gravity SEPARATION diameter, ft CALCULATIONS: 1. Calculate design specification information pg = (P+Pa)(MW) 10.73*(T+460)*(z) pl = 62.4(sp. gr.) m=MMSCFD(1e6)(MW) 379.4(24)(3600) Qa=m/pg Ql=42W/7.481/86400 Qm=Qa+Ql pm=(pl*Ql+pg*Qg)/Qm
12 22 120 600 0.9 0.012
(shaded cells require input)
14.7 50 0.5 3
2.41 lb/cu ft 31.20 lb/cu ft 8.05 lb/sec 3.34 0.0032 3.34 2.44
acfs cu ft/sec cu ft/sec lb/cu ft
2. Calculate actual velocity Vt = Qa/A
0.47 ft/sec
3. Assume C D and calculate Dp until converged Trial No. Assume CD
1 0.34
Dp = 3CDpgVt2/4g(pl-pg) Re = 1488(DpVtrg)/m Calculated CD Dp dm
2 2.14
0.000148 0.000933
3 0.78
4 1.27
0.000341 0.000553
20.90
131.82
48.15
78.11
2.14
0.78
1.27
0.99
0.000466 ft 142 micron
cells require input)
5 0.99
6 1.12
7 1.05
8 1.09
9 1.07
10 1.08
11 1.07
0.000429 0.000488 0.000457 0.000472 0.000464 0.000468 0.000466 60.65
68.90
64.52
66.72
65.58
66.16
65.86
1.12
1.05
1.09
1.07
1.08
1.07
1.07
EXAMPLE 4: SIZE A 2-PHASE HORIZONTAL SEPARATOR JOB SPECIFICATIONS: GAS Flow, MMSCFD MW Temp, deg F Pres, PSIG compressibility factor viscosity, cp ATM PRES PSIA LIQUID Flow, BPD specific gravity minimum level, in. SEPARATION remove drops >__micron residence Time, min Flow Character (slug, free, entrained, mist) APPLICATION TYPE: TYPE OF VESSEL: VESSEL CONFIGURATION: MIST EXTRACTOR: CALCULATIONS: 1. Calculate design specification information pg = (P+Pa)(MW) 10.73*(T+460)*(z) pl = 62.4(sp. gr.) Dp= 0.00003937(micron)/12 m=MMSCFD(1e6)(MW) 379.4(24)(3600) Qa=m/pg Ql=42W/7.481/86400 Qm=Qa+Ql pm=(pl*Ql+pg*Qg)/Qm 2. Calculate minimum diameter for gas capacity Method 1a: Equation 10 and Figure 8 Souders-Brown K (From Table) Vt=K((pl-pg)/pg)^0.5 Minimum dia.= 12*(TZQg/2.4Vt(P+Pa))^0.5 Stokes' Law Re = 1488(DpVtrg)/m Vt = 1488gDp2(rl-rg)/18m Minimum dia.= 12*(TZQg/2.4Vt(P+Pa))^0.5 Newton's Law Re = 1488(DpVtrg)/m
12 22 120 600 0.9 0.012
(shaded cells require input)
14.7 5 0.5 8
API
151.5
150 3 free liquid intercept Inlet sep horizontal yes
2.41 lb/cu ft 31.20 lb/cu ft 0.000492 ft 8.05 lb/sec 3.34 0.0003 3.34 2.42
acfs cu ft/sec cu ft/sec lb/cu ft
0.4 1.381 ft/sec 21.0 in
2 ft Stokes' Law Not Applicable
227.85 1.546 ft/sec 19.9 in
2 ft Newton's Law Not Applicable
111.43
Vt = 1.74(gDp(rl-rg)/rg)^0.5
0.756 ft/sec
Minimum dia.= 12*(TZQg/2.4Vt(P+Pa))^0.5
28.4 in
Intermediate Range - Iteration Trial No. Assume CD
1 0.34
2 0.80
Vt = (4gDp(rl-rg)/3CDrg)^0.5
0.86
0.56
0.51
0.50
Re = 1488(DpVtrg)/m
2.5 ft Intermediate Range Is Applicable 3 4 0.96 1.00
126.82
82.90
75.51
73.84
Calculated CD
0.80
0.96
1.00
1.01
Minimum dia.= 12*(TZQg/2.4Vt(P+Pa))^0.5
35.0 in
3. Calculate vessel liquid capacity requirements Leff and Lss for Gas Capacity Vessel Full - beta alpha dvLeff Leff Lss Leff and Lss for Liquid Capacity d^2*Leff Leff Lss Lss Lss/Dv
3 ft
50% 0.50 102.10 2.91 5.9
6 ft
21.4 0.02 0.02
0.5 ft
6 2
d cells require input)
' Law Not Applicable
n's Law Not Applicable
ediate Range Is Applicable 5 6 1.01 1.02 0.50
0.50
73.43
73.33
1.02
1.02
EXAMPLE 4: SIZE A 3-PHASE HORIZONTAL SEPARATOR Gas Flowrate (MMSCFD) Oil Flowrate (BOPD) Water Flowrate (BWPD) Total Liquid (BPD) ATM Press. Op Press (psig) Op Temp (F) Gas Compressibility Z Retention Time (min) t Remove drops >__micron from gas Remove H2O drops >__micron from oil Remove oil drops >__micron from H2O Vessel Liquid Level - beta 1. Calculate design specification information rg = (P+Pa)(MW) 10.73*(T+460)*(z) rl = 62.4(sp. gr.) rw = 62.4(sp. Gr H2O.) Dp= 0.00003937(micron)/12 Dw= 0.00003937(micron)/12 Do = 0.00003937(micron)/12 m=MMSCFD(1e6)(MW) 379.4(24)(3600) Qa=m/rg Ql Qw Qm=Qa+Ql+Qw pm=(rl*Ql+rg*Qg+rw*Qw)/Qm Fractional area of liquids - alpha
12.00 500 500 1000.00 14.7 600.00 120 0.90 3.00 150 500 200 50%
Gas MW Oil S.G. Water S.G.
2.41
lb/cu ft
31.20 68.64 0.000492 0.001640 0.000656 8.05
lb/cu ft lb/cu ft ft ft ft lb/sec
3.34 0.0325 0.0325 3.40 3.32 0.50
2. Calculate C D and min diameter Trial No. Assume CD
acfs cu ft/sec cu ft/sec cu ft/sec lb/cu ft
1 2.01
Vt = (4gDp(rl-rg)/3CDrg)^0.5
22 0.5 1.1
2 1.22
3 1.06
0.35
0.46
0.49
52.16
67.07
71.69
Calculated CD
1.22
1.06
1.03
Minimum dia.= 12*(TZQg/2.4Vt(P+Pa))^0.5
35.1 in
Re = 1488(DpVtrg)/m
3. Determine the fractional height of water in the vessel Fractional area of water aw=atQw/t(Qw+Ql) 0.250 Fractional height of water bw 0.298 Fractional area of water aw 0.250 4. Calculate max vessel diameter for water settling Vtw = 1488gDw2(pw-pl)/18ml 0.03 Max Height of Oil Pad, Ho 57.93 Maximum diameter = Ho/(b-bw) 287
36
change until above matches below
ft/sec in max in max
5. Calculate max vessel diameter for oil settling Vtw = 1488gDw2(pw-pl)/18mw Max Height of water, Hw Maximum diameter = Hw/bw Maximum Vessel Diameter
0.0429 92.68 311
ft/sec in max in max
287
282
6. Calculate vessel gas and liquid capacity requirements dvLeff (for gas capacity) 102.12 dv^2*Leff (for liquid capacity) 4286 7. Determine appropriate diameter and S-S length Diameter (in) Leff (gas) Lss (gas) Leff (liquid) Lss (liquid) Lss (ft) L/D
36 2.84 5.84 3.31 4.41 6 2.00
42 2.43 5.93 2.43 3.24 6 1.71
48 2.13 6.13 1.86 2.48 7 1.63
Gas Viscosity m Oil Viscosity ml H2O Viscosity mw
4 1.03
in
matches below
0.012 10 1
cp cp cp
5 1.02
6 1.02
0.49
0.50
0.50
72.89
73.20
73.27
1.02
1.02
1.02
in
54 1.89 6.39 1.47 1.96 7 1.44
60 1.70 6.70 1.19 1.59 7 1.40
66 1.55 7.05 0.98 1.31 8 1.36
