Separator_Calcs.xls

EXAMPLE 1: SIZE A 2-PHASE VERTICAL SEPARATOR

JOB SPECIFICATIONS:GAS

Flow, MMSCFD 12 (shaded cells require input)MW 22Temp, deg F 120Pres, PSIG 600compressibility factor 0.9viscosity, cp 0.012

ATM PRESPSIA 14.7

LIQUIDFlow, BPD 50specific gravity 0.5minimum level, in. 8

SEPARATIONremove drops >__micron 150Flow Character (slug, free, entrained, mist) free liquidAPPLICATION TYPE: interceptTYPE OF VESSEL: knockoutVESSEL CONFIGURATION: verticalMIST EXTRACTOR: no

CALCULATIONS:1. Calculate design specification information

2.41 lb/cu ft 10.73*(T+460)*(z) pl = 62.4(sp. gr.) 31.20 lb/cu ftDp= 0.00003937(micron)/12 0.000492 ft

8.05 lb/sec 379.4(24)(3600)Qa=m/pg 3.34 acfsQl=42W/7.481/86400 0.0032 cu ft/secQm=Qa+Ql 3.34 cu ft/secpm=(pl*Ql+pg*Qg)/Qm 2.44 lb/cu ft

2. Calculate minimum diameter for gas capacity

5464.84

1.70

0.38 ft/sec

39.9 in 3.5 ft

Method 1b: Stokes' Law, Newton's Law, IntermediateStokes' Law Stokes' Law Not Applicable

227.85

1.546 ft/sec

19.9 in 2 ft

pg = (P+Pa)(MW)

m=MMSCFD(1e6)(MW)

Method 1a: Equation 10 and Figure 8

CDRe^2 (Eq. 10)

CD from Fig 8

Vt = (4gDp2(rl-rg)/3CDrg)^0.5

Minimum dia.= 12*(TZQg/2.4Vt(P+Pa))^0.5

Re = 1488(DpVtrg)/m

Vt = 1488gDp2(rl-rg)/18m


Newton's Law Newton's Law Not Applicable

111.43

0.756 ft/sec

28.4 in 2.5 ft

Intermediate Range - Iteration Intermediate Range Is ApplicableTrial No. 1 2 3 4 5

0.34 0.80 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

0.80 0.96 1.00 1.01 1.02

35.0 in 3 ft

Re = 1488(DpVtrg)/m

Vt = 1.74(gDp(rl-rg)/rg)^0.5


Assume CD

Vt = (4gDp(rl-rg)/3CDrg)^0.5

Re = 1488(DpVtrg)/m

Calculated CD


3. Calculate vessel liquid capacity requirementsMethod 3a: Arnold-StewartVessel Diameter, dv 36 inResidence Time, t 3 minLiquid Height, h 0.965 inLss = (h+76)/12 6.4 ftLss = (h + dv + 40)/12 6.4 ftVessel height S/S 6.4 ft 6.5 ft

L/D 2.167

Method 3b: Svrcek-Monnery Vessel Diameter 3 fthold up time, t1 3 minhold up volume, Vh=60Ql*t1 0.585 cu ftsurge time, t2 3 minsurge volume, Vs=60Ql*t2 0.585 cu ftlow liquid level, Hlll 8 in

0.993 in0.993 in

3.99 incenterline inlet, Hlin-Hhll=12+dn 15.99 indisengagement, Hd-Hlin=36+dn/2 38.00 inmist extractor, Hme 0.00 inVessel height, Ht=Hlll+Hnll+Hlin+Hdme 63.98 in 5.5 ft

L/D 1.833

Method 3c. GPSA Engineering Databook

Vessel Diameter 36 inMist Extractor Depth 0 inInlet Nozzle Diameter 4 in

Mist Extractor Btm to Top Seam 0 inDisengagement Area = Greater of Dv or 24" 36 in

8 in TimeLevel Gauge to Hi-Level SD (12-inch Min.) 12 in 36.3 minLevel Gauge & Controller (12-inch Min.) 12 in 36.3 minLo-Level SD to Level Gauge (12-inch Min.) 12 in 36.3 minMinimum Level 8 in

Vessel height S/S 88 in 7.5 ft

L/D 2.500

norm liq level, Hh = Hnll-Hlll = 4*12Vh/pDv^2high liquid level, Hs = Hhll-Hnll = 4*12Vs/pDv^2inlet nozzle, dn=(4Qm/(p*60/pm^0.5))^0.5*12

inlet nozzle area, 2*(4Qm/(p*60/pm^0.5))^0.5*12

Newton's Law Not Applicable

Intermediate Range Is Applicable6

1.02

0.50

73.33

1.02

EXAMPLE 2: COMPARE 4 METHODS FOR DETERMINING DIAMETER



ATM PRESPSIA 14.7

LIQUIDFlow, BPD 50specific gravity 0.5

SEPARATIONremove drops >__micron 150Flow Character (slug, free, entrained, mist) free liquidAPPLICATION TYPE: interceptTYPE OF VESSEL: knockoutVESSEL CONFIGURATION: verticalMIST EXTRACTOR: no




2. Calculate minimum diameter for gas capacity

5464.84

1.30

0.44 ft/sec

37.3 in 3.5 ft

With DemisterK (From Table) 0.18

0.622 ft/sec

31.4 in 3 ftWithout DemisterK (From Table) 0.09

0.311 ft/sec

44.4 in 4 ft

pg = (P+Pa)(MW)

m=MMSCFD(1e6)(MW)

Method 1: Equation 10 and Figure 8

CDRe^2 (Eq. 10)

CD from Fig 8

Vt = (4gDp2(rl-rg)/3CDrg)^0.5


Method 2: Souders-Brown with and without demister

Vt=K((pl-pg)/pg)^0.5




Method 3: Newton's Law Newton's Law Not Applicable

111.43

0.756 ft/sec

28.4 in 2.5 ft

Method 4: Stokes' Law Stokes' Law Not Applicable

227.85

1.546 ft/sec

19.9 in 2 ft

Intermediate Range - Iteration Intermediate Range Is ApplicableTrial No. 1 2 3 4

0.34 0.80 0.96 1.00

0.86 0.56 0.51 0.50

126.82 82.90 75.51 73.84

0.80 0.96 1.00 1.01

35.0 in 3 ft

Re = 1488(DpVtrg)/m

Vt = 1.74(gDp(rl-rg)/rg)^0.5


Re = 1488(DpVtrg)/m



Assume CD


Re = 1488(DpVtrg)/m

Calculated CD


(shaded cells require input)


Stokes' Law Not Applicable

Intermediate Range Is Applicable5 6

1.01 1.02

0.50 0.50

73.43 73.33

1.02 1.02

EXAMPLE 3: EXISTING SEPARATOR



ATM PRESPSIA 14.7

LIQUIDFlow, BPD 50specific gravity 0.5

SEPARATIONdiameter, ft 3


2.41 lb/cu ft 10.73*(T+460)*(z) pl = 62.4(sp. gr.) 31.20 lb/cu ft


2. Calculate actual velocityVt = Qa/A 0.47 ft/sec

Trial No. 1 2 3 4

0.34 2.14 0.78 1.27

0.000148 0.000933 0.000341 ###

20.90 131.82 48.15 78.11

2.14 0.78 1.27 0.99

Dp 0.000466 ftdm 142 micron

pg = (P+Pa)(MW)

m=MMSCFD(1e6)(MW)

3. Assume CD and calculate Dp until converged

Assume CD

Dp = 3CDpgVt2/4g(pl-pg)

Re = 1488(DpVtrg)/m

Calculated CD


5 6 7 8 9 10 11

0.99 1.12 1.05 1.09 1.07 1.08 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



ATM PRESPSIA 14.7

LIQUIDFlow, BPD 5specific gravity 0.5 API 151.5minimum level, in. 8

SEPARATIONremove drops >__micron 150residence Time, min 3Flow Character (slug, free, entrained, mist) free liquidAPPLICATION TYPE: interceptTYPE OF VESSEL: Inlet sepVESSEL CONFIGURATION: horizontalMIST EXTRACTOR: yes




2. Calculate minimum diameter for gas capacitySouders-BrownK (From Table) 0.4

1.381 ft/sec

21.0 in 2 ft

Stokes' Law Stokes' Law Not Applicable

227.85

1.546 ft/sec

19.9 in 2 ft

Newton's Law Newton's Law Not Applicable

111.43

0.756 ft/sec

28.4 in 2.5 ft

pg = (P+Pa)(MW)

m=MMSCFD(1e6)(MW)

Method 1a: Equation 10 and Figure 8



Re = 1488(DpVtrg)/m



Re = 1488(DpVtrg)/m

Vt = 1.74(gDp(rl-rg)/rg)^0.5


Intermediate Range - Iteration Intermediate Range Is ApplicableTrial No. 1 2 3 4

0.34 0.80 0.96 1.00

0.86 0.56 0.51 0.50

126.82 82.90 75.51 73.84

0.80 0.96 1.00 1.01

35.0 in 3 ft

3. Calculate vessel liquid capacity requirementsLeff and Lss for Gas CapacityVessel Full - beta 50%alpha 0.50dvLeff 102.10Leff 2.91Lss 5.9 6 ft

Leff and Lss for Liquid Capacityd^2*Leff 21.4Leff 0.02Lss 0.02 0.5 ft

Lss 6Lss/Dv 2

Assume CD


Re = 1488(DpVtrg)/m

Calculated CD



Stokes' Law Not Applicable


Intermediate Range Is Applicable5 6

1.01 1.02

0.50 0.50

73.43 73.33

1.02 1.02

EXAMPLE 4: SIZE A 3-PHASE HORIZONTAL SEPARATORGas Flowrate (MMSCFD) 12.00 Gas MW 22Oil Flowrate (BOPD) 500 Oil S.G. 0.5Water Flowrate (BWPD) 500 Water S.G. 1.1Total Liquid (BPD) 1000.00ATM Press. 14.7Op Press (psig) 600.00Op Temp (F) 120Gas Compressibility Z 0.90Retention Time (min) t 3.00Remove drops >__micron from gas 150Remove H2O drops >__micron from oil 500Remove oil drops >__micron from H2O 200Vessel Liquid Level - beta 50%

1. Calculate design specification information2.41 lb/cu ft

10.73*(T+460)*(z) 31.20 lb/cu ft68.64 lb/cu ft

Dp= 0.00003937(micron)/12 0.000492 ftDw= 0.00003937(micron)/12 0.001640 ftDo = 0.00003937(micron)/12 0.000656 ft

8.05 lb/sec 379.4(24)(3600)

3.34 acfsQl 0.0325 cu ft/secQw 0.0325 cu ft/secQm=Qa+Ql+Qw 3.40 cu ft/sec

3.32 lb/cu ftFractional area of liquids - alpha 0.50

Trial No. 1 2 3

2.01 1.22 1.06

0.35 0.46 0.49

52.16 67.07 71.69

1.22 1.06 1.03

35.1 in 36

3. Determine the fractional height of water in the vessel0.2500.298 change until above matches below0.250

4. Calculate max vessel diameter for water settling0.03 ft/sec

Max Height of Oil Pad, Ho 57.93 in max

rg = (P+Pa)(MW)

rl = 62.4(sp. gr.)rw = 62.4(sp. Gr H2O.)

m=MMSCFD(1e6)(MW)

Qa=m/rg

pm=(rl*Ql+rg*Qg+rw*Qw)/Qm

2. Calculate CD and min diameter

Assume CD


Re = 1488(DpVtrg)/m

Calculated CD


Fractional area of water aw=atQw/t(Qw+Ql)Fractional height of water bwFractional area of water aw

Vtw = 1488gDw2(pw-pl)/18ml

B11

Minimum size of liquid droplet in gas

B12

Minimum size of droplet of heavy liquid in light liquid

B13

Minimum size of light liquid in heavy liquid

287 in max

5. Calculate max vessel diameter for oil settling0.0429 ft/sec

Max Height of water, Hw 92.68 in max311 in max

Maximum Vessel Diameter 287 282

6. Calculate vessel gas and liquid capacity requirementsdvLeff (for gas capacity) 102.12dv^2*Leff (for liquid capacity) 4286

7. Determine appropriate diameter and S-S lengthDiameter (in) 36 42 48Leff (gas) 2.84 2.43 2.13Lss (gas) 5.84 5.93 6.13Leff (liquid) 3.31 2.43 1.86Lss (liquid) 4.41 3.24 2.48Lss (ft) 6 6 7L/D 2.00 1.71 1.63

Maximum diameter = Ho/(b-bw)

Vtw = 1488gDw2(pw-pl)/18mw

Maximum diameter = Hw/bw

0.012 cp10 cp1 cp

4 5 6

1.03 1.02 1.02

0.49 0.50 0.50

72.89 73.20 73.27

1.02 1.02 1.02

in

change until above matches below

Gas Viscosity mOil Viscosity mlH2O Viscosity mw

in

54 60 661.89 1.70 1.556.39 6.70 7.051.47 1.19 0.981.96 1.59 1.31

7 7 81.44 1.40 1.36

Documents

Separator_Calcs.xls