3phase separator size 2015 vera

Client: E3 OGPE Datasheet No:Project: E3 Field Development Rev : A Date: 20-Oct-10Plant: Gas - Liquid Inlet Separation By: K Chk'd: App'd:Unit: Inlet Item No: 5V - 100Service:Production Separator Location:

1 Units Separator Type Number Required: 12 Internals 2 13 Feed Inlet Vapour Outlet Liquid Separation 3 14 2 15 Process Design Conditions6 Inlet Pressure psia = 130 * Inlet Temperature °F = 100.07 Pressure Drop Allowed psi = * Pressure Drop Calculated psi =8 Operating & Design Cases Case 1 Case 2 Case 3 Design9 Vapour Nat Gas Nat Gas

10 Flow Rate MMSCFD = 75.011 Flow Rate lb/h = 186,16012 Flow Surge Factor % = 0%13 Density lb/ft³ = 0.49014 Viscosity cP = 0.01215 Light Liquid = Oil Oil16 Flow Rate BFPD = 50,00017 Flow Rate lb/h = 657,89818 Flow Surge Factor % = 0%19 Density lb/ft³ = 56.2020 Viscosity cP = 221 Heavy Liquid = Water Water22 Flow Rate BFPD = 50,00023 Flow Rate lb/h = 735,16024 Flow Surge Factor % = 0%25 Density lb/ft³ = 62.826 Viscosity cP = 1.12728 Contaminants/ Solids Specify29 Short term operating requirements3031 Design Considerations32 Default33 Allowable Droplet Size μ = 200 30034 In horizontal separator, maximum vapour velocity / min area is calculated at35 Liquid Residence Time at NLL min = 336 Liquid Control Time between LAL and LAH min = 537 Liquid Slug Hold up (NLL to LAHH) Water + Oil Sides ft³ = +38 Inflow Slug duration - all liquid flow at total volume flow rate sec = 239 Operator Response Time Reqd between Alarm & Trip min = 1 0.540 LALL to consider:4142 Nozzle sizing: Inlet Device: Vane Distributor lb/ft.s² = 4,03243 Vapour Outlet lb/ft.s² = 2,68844 Horizontal Separator: Inlet Nozzle Outlet Nozzle:4546 Design Notes4748495051

ρmV

m²

ρgV

g²

Wellmud CokeSand

outlet SDV closing time

Outlet siphon effect

Proppant


5253

1 Vessel Design Conditions2 Design Pressure psig = Design Temp °F =3 Vacuum Criteria Min Design Metal Temp °F =4 Limitations Plot Limitations5 Shell Diameter, OD/ID ft = 11.5 Length (Tan-Tan) ft = 35.06 Design Code = Corrosion Allowance in =7 Wall thickness = Hydrostatic Test Pressure psig =8 Material of Construction Shell =9 Vane Distributor Mesh Pad =

10 Sandjet Nozzles = Coalescer/Calming Baffl =1112 External Insulation 113 Insulation Thick in = Type/ Material =14 Anchor = Type/ Material =15 Post Weld Heat Treatment Yes/ No % Welds fully radiographed16 Painting Requirements17 Heating Coil18 Sand Wash Facility No and Size of Nozzles19 Water demand = Effluent sand + water flow =20 Mesh pad/Internal cleaning solvent injection nozzles?21 Vessel Nozzles2223 Mark No Service Dia, in Flange Remarks24 Inlets & Outlets Minimum Elevation of Bottom of Vessel25 N1 1 Feed 28 Inlet: No valve or expansion/contraction within 10d26 N2 1 Vapour Outlet 16 Vapour Outlet: Reducer if any should be 2d away.27 N3 1 Liquid Outlet 14 Liquid Outlet: SDV if any should at min distance.28 N4 1 Liquid Outlet 1429 N5 1 Vent 2 Suggested Levels

30 N6 1 Drain 3 Oil Water

31 N7 1 Relief Valve Level in in

32 N8 1 Utility Connection 2 LAHH 96.0 66.0

33 N9 LAH 90.0 60.0

34 NLL 54.0 45.0

35 Instrumentation LAL 48.0 27.0

36 K1 PG LALL 24.0 21.0

37 K2 TG38 K3A/B LT39 K4A/B Not used40 K5A/B LG41 K6A/B Not used42 K7A/B Not used43 K8A/B LAHH44 K9A/B LALL45 K10A/B Not used46 K10A/B Not used474849 Manholes

None Heat Conservation

Personnel Protection

Fire Protection


50 M1 2 1851 H15253

Client: E3 OGPE Calculation No:

Project: E3 Field Development Rev : A Date: 20 Aug 2010

Service:Production Separator 5V - 100 By: K Chk'd: App'd:

Horizontal Mesh Pad Weir Type 3 Phase Separator

Vapour & Liquid Flow Rates Vapour Light Liq Heavy Liq Total

Mass Flow Rate lb/s = 51.7 182.7 204.2 438.7

Volume Flow Rate ft³/s = 105.5 3.25 3.25 112.0

Mixture Density lb/ft³ = 3.92

Nozzle Sizing

Number Diameter, in Velocity Criteria

Location off Min Select ID ft ft/s Parameter Calcul Allowed Remarks

Feed Inlet 1 25 28 2.33 26.20 2,688 4,032 OK

Vapour Outlet 1 16 16 1.25 86.00 3,624 2,688 High

Water Outlet 1 13 14 1.09 3.46 Vliquid ft/s 3.5 3.3 High

Oil Outlet 1 13 14 1.09 3.46 Vliquid ft/s 3.5 3.3 High

Size, in No Size, in No Size, in No

Miscellaneous Vent 2 1 Manholes 18 2 Utility 2 1

Drain 3 1 Hand holes add check valve on utility nozzle

Vapour Separation

Allowable Droplet Size μ = 200.0 0.001 ft

CRe² = 5,088

Log CRe² = 3.7

C = 1.28

Vt, Liquid droplet free settling velocity ft/s = 1.58

Allowable Vapour Velocity ft/s = 4.25 User K = Default K = 0.40

Design Vapour Flow ft³/s = 105.5 Use 80% for compr, glycol, amine drums

Horizontal Separator. Trial & Error. Dia Vs Length and Levels. In 2-3 tries you'd get it

Vessel Diameter - Selected D ft = 11.5

Liquid Level LAHH in = 96 Input first preliminary levels below

Vapour Space Height, h ft = 3.5 OK

Vapour Flow Area ft² = 26.74

Vapour Velocity ft/s = 3.95 Less than allowable. OK

Liquid Gas Separation

Vessel Length L ft = 35.0 Horiz Sep. Enter D & L first; then levels

Second Compartment Length L2 ft = 3.0 First try with min 3' (0.9m)

First Compartment Length L1 ft = 32.00

Vapour Travel Length ~ ft = 29.13

Degassing Area Ag ft² = 392.87

Design Oil + Water Flow ft³/s = 3.25 + 3.25

Design Liquid Flow ft³/s = 6.50 Liquid Downward Velocity ft/s = 0.02

ρmV

m²

ρgV

g²

Size nozzles first, as they decide 'net' travel distance in horizontal KODs




Gas Bubble Size - to be removed μ = 200 Gas Rising Velocity ft/s = 0.0319

* Gas Separation O.K *

Liquid - Liquid Separation

0 Oil Weir Height, H in = 66.0

0 9.0

1 24.0

0 30.0

Bucket to Weir gap, g 0.0

Water Levels - In 1st Compartment

Level Volume IntraVolumeResponse Time, min Remarks

Settings in ft³ ft³ Available Required

Mud Level 6.0 51.6

280.08 86 14.00 sec OK

LALL 21.0 331.7

146.80 0.8 1.0 Time not enough for op intervention

LAL 27.0 478.5

NLL 45.0 990.7 5.1 3.0 OK

LAH 60.0 1466.9

196.12 1.0 1.0 OK

Weir 66.0 1,663 No LAHH for I/P. Enter Weir Ht, H

Control Vol LAL to LAH ft³ 988.4 5.1 5.0 OK

Slug Vol NLL to LAHH ft³ 672.3 0.0 OK

Slug, inflow all liquid ft³/s 112.04 6.0 sec 2.0 sec OK

Oil Levels - In 2nd Compartment

Level Volume IntraVolumeResponse Time, min Remarks

Settings in ft³ ft³ Available Required

Mud Level 6.0 678.1

46.44 14 14.00 sec OK

LALL 24.0 724.5

99.61 0.5 1.0 Time not enough for op intervention

LAL 48.0 824.1

NLL 54.0 852.9 4.4 3.0 OK

LAH 90.0 1807.5

LALL

NLL Flooded WeirLAHH

L2L1Weir Type

NLL2

LALL

NLLNLL Overflow Weir

H

More sketches on RHS (right hand side) - see AK35:AS45




211.42 1.1 1.0 OK

LAHH 96.0 2,019

Control Vol LAL to LAH ft³ 983.4 5.0 5.0 OK

Slug Vol NLL to LAHH ft³ 1,166 0.0 OKSlug, inflow all liquid 0 112.04 10.4 sec 2 sec OK

Oil - Water Droplet Size in Carry-overWater Velocity ft/s = 0.1106 Oil Velocity ft/s = 0.1655Travel Length ft = 30.02 Travel Length ft = 30.02Water Travel Time sec = 271.5 Oil Travel Time sec = 181.4Oil Rising distance ft = 3.75 Water Settling distance ft = 1.75Oil Terminal Velocity ft/s = 0.014 Water Terminal Velocity ft/s = 0.010Oil in Water Droplet Size μ = 283.46 Water in Oil in Droplet Size μ = 319.4A mesh/vane type coalescer may help reduce droplet size/ carry over, rather than a bigger vessel.

Droplets smaller than 150-200 μ generally OKSand Droplet Size, μ = Later Sand Accumulation, % =

Sand Accumulation per day ft³ =

Vessel SizeVessel Diameter D ft = 11.5 DefaultInlet to Demister ft = 11.67Demister ft = 0.50

0 Demister to Outlet Nozzle ft = 7.00Outlet nozzle to Tan Line ft = 2.22

0.00Minimum Length Required = 0.00 21.39

Selected Length L = 35.00L/D Ratio = 3.04 OK

RemarksSpace to explain design features, add comments on caution messages

Client: E3 OGPE Calculation No:Project: E3 Field Development Rev : Date:Service:Production Separator 5V - 100 By: Chk'd: App'd:

Vapour & Liquid Flow RatesDesign Vapour Flow ft³/s = 105.5Design Liquid Flow ft³/s = 6.5Hold-up Liquid Volume ft³ = 1,951.1

Separator SizingVertical Horizontal

Allowable Vap Velocity ft/s = 3.2 Allow Vapour Velocity ft/s = 4.8Vapour Flow Area ft² = 33.0 Vapour Flow Area ft² = 22.0

Min Dia ft = 5.9Vessel Diameter, D ft = 6.5 7.0 Selected Dia ft = 12.0Vessel X Area ft² = 33.18 38.48 0.5Liquid LAHH D ft 12.0 12.5 13.0 13.5 14.0

For Liquid Hold up ft = 58.8 50.7 L ft 21.4 19.4 17.6 16.1 14.8For Level Gaps ft = 1.8 1.8 L/D 1.8 1.5 1.4 1.2 1.1

Vapour Space ft = 9.0 9.0Suggested Height, L ft = 67.7 59.6 Try # 1 Smaller Dia x Longer DrumL/D = 10.4 8.5 Assume Liquid X Secn % = 30% Note 1

Vessel Diameter, D ft = 12.00Vessel X Secn ft² = 113.1Liquid X Secn ft² = 33.9

Min LAHH ft = 4.1α = 1.25

Calculated Liquid X Secn % = 0.30Ratio: assumed/ calculated = 1.0

This quick-Sing calculation ignores liquid level Note 1: Goal seek on W24 to make W32 as 1settings. Do, a proper detailed analysis after Length - Liquid Holdup ft = 57.5checking the likely size Suggested Length, L ft = 57.5

L/D = 4.8

SMKumar Energy EnvRev A Oct 2010

Conversion Factors SMKumar Energy EnvRev A Oct 2010Goal Seek to get reverse and inter-conversion

Flow gpm MMGPD AcreFt/d l/s BPD m³/h m³/d1 0.002223 0.001439 0.004405 0.063091 34.28571 0.227129 5.451104

Volume gallon Imp Gall AcreFt l bbl m³1 0.1337 0.833 325,829 3.785 0.02381 0.003785

Pressure psi ft Water in Hg ft Liquid m Water m Liquid kg/cm² bar kPa14.7 33.957 29.988 15.435 10.35009 4.704588 1.03341 1.013793 101.3793

of Sp Gra2.2

Temperatu°F °R °C °K32 491.67 0 273.15

Length Ft Mile in m cm10 0.001894 120.0 3.05 304.80

HP GPM Ft Sp.Gr Eff, % BHP880 55 2.2 70.0% 38.4127

GPM psi Eff, % BHP880 53 70.0% 38.85048

ft³/s

ft³

Separator Sizing

Read first GPSA Section 7, Separation Equipment

Industry PracticeUpstream Oil & Gas Process Engineers size the separators for preliminary layout and to checksupplier design. Design and performance responsibility rests with the vessel and internal (inlet device,coalescer, mesh pad, vane etc) supplier. It makes sense as the ½ an hour charged using thisprogram may get a company a net revenue of say US $ 20/= but shoulders it with a $ 50-200Kresponsibility. Info on both the pages of the Datasheet is usually passed to the supplier indicating Dand L as minimum.

Downstream Refinery/Petchem/Fertilizer/Chemical Process Engineers usually shoulder the sizingresponsibility. Info on the second sheet of Datasheet alone may be given to the suppliers, if processdata/info is considered CONFIDENTIAL and proprietary.

Separator TypesVertical High gas flow with low liquid holdups. Compressor Scrubbers/ KODs.Horizontal High liquid flow with high liquid holdups. Production Separators, Flare KODs. Column

Feed Drums. Full drum cross-sectional area is available for vapour flow in verticaldrum. In horizontal drums, liquid may occupy 50 to 80% cross sectional area.Horizontal drum may provide a longer travel time for vapour (= longer settling time forliquid droplets) and shorter dropping out time/ distance for liquids resulting in higherallowable vapour velocity and smaller diameter than a vertical drum.

Name KOD, Accumulators, Flash Drum, Reflux Drum, Steam Drum

Service Hydrocarbon, Steam, Air

Gravity The intermediate law is usually valid for many of the gas liquid and liquid-liquidSeparation separation applications encountered in the oil & gas plants.

KOD No internals. For waxy, coking and dirty service. High liquid loads where vapourseparation is not an issue. In flare KODs where internals are avoided. Note: In long horizontal drum, allowable vapour velocity based on gravity separationmay be higher than that based on mesh pad or vane pack.

Go for 150 μ in continuous service requiring fine separation and no internals like vanesor mesh pad are allowed. Go for 400 μ in Flare KODs for continuous (dumping) loads; 600 μ in low probability loads like design blocked outlet flow or intermittent one likeblowdown. Droplets formed as a result of chilling/condensation caused via highpressure PSV or BDV are too fine (0.1 to 50 μ) to be trapped in a KOD.

Impingement Impingement type mesh pad and vane pack are sized based on Souders and BrownSeparation Equation, Vallowed = K.sqrt((ρl - ρg)/ρg). Lower the K, lower is gas velocity and higher

is the removal efficiency. Use lower K in Compressor, Glycol and Amine Unit service.

Wire mesh Non-fouling clean service. Can trap 3 - 10 μ droplets and preferred in compressordrums. Wire mesh is made of wires of 0.25 to 0.3 mm with a surface area > 100 ft²/ft³.Horizontal sep may have the mesh pad horizontally below vapour outlet or verticallyextending into the liquid pool to LALL level. Min pad thickness is 4"; normal 6". Padbulk density 9 - 12 lb/ft³. A 12" mesh pad near the inlet to LAHH level may be used asa coaleser pack in clean liquid-liquid (water-oil (condensate)) separation. For Prod Sepwith sand/mud, consider perforated plates or vanes.

Vane 6 - 12" thick. Can trap 10 - 40 μ droplets only. Arranged in a zigzag or sinusoidalpattern with vane spacing of 1 - 1.5". Less likely to plug by solids and viscous oil due

to their relatively large flow passages

K Factor Several sources give different values for K. For instance API 12J gives lower orconservative values for vertical separators. But its K value for longer horizontal drum ishigh and unrealistic. The program recommends an average value as a default andallows the user to input a desire value. K is decided by difficulty or ease of separation.Best is go by successful previous experience.

During start-up/ commissioning, you will be left holding the baby and others would have vanished. If acompressor is damaged, blamed on droplet carried over and deposited on blades + causingunbalanced loads, 1 day production loss is hefty, compared to the 200 mm you saved on dia. No oneremembers a good design. A poor design is remembered and is talk of the town.

K Factor, GPSAft/s Vertical Horizontal

Mesh pad 0.22 0.39Vane Pack 0.45 0.90

K Factor, Mesh pad API 12J, based on vessel height or lengthft/s Vertical Horizontal

5' (1.5m) 0.2410' (3 m) 0.35 0.45

L' 0.45*(L/10)^0.56

Some vendors consider higher Ks based on vapour space (between LAHH and Mesh pad bottom) asbelow. Suggest that you take 0.3 fps (0.1 m/s) in all new applications. You may consider higher valuesin revamp jobs, if operational feedbacks favour it; less likely as Mesh pads usually get fouled up inservice, reducing their effectiveness

K Factor Vendor 1Vapour Space in 3 4 5 6 7 8K ft/s 0.12 0.15 0.19 0.22 0.25 0.29Vapour Space in 9 10 11 12 13 14K ft/s 0.32 0.35 0.38 0.40 0.42 0.43

Note: K is for velocity thru the Mesh pad or vanes; not necessarily for velocity in the drum.

Ideally K should be based on the desired separation needed. For instance a Compressor KOD can nottolerate liquid droplets (droplets may damage the blades rotating at high speed, evaporate, leavingresidue or coke up) leading to unbalanced load on shaft.

But a separator feeding a column or a cooler/ condenser may allow higher liquid loading. Thusselection of K should be based on service and should not be a magic number for all applications.

K Factor Vendor - Based on ServiceService Compress Column Condenser Fuel Gas Vane Vert Vane HorK ft/s 0.25 0.35 0.45 0.30 0.40 0.65

K Correction for Op Pressure, GPSA K Correction for Viscositypsig 150 300 600 1,150 Note: Vertical Separator - Mesh pad K

% 90 85 80 75 Factor requires viscosity correction. 0.9 for μ = 100 cp and 0.8 for μ = 1,000 cp

It is common in Oil & Gas applications to have flow surges into the first or Inlet (Production) Separator and suitable margins are added to flow. Ignore the margins, if design rate includes a higher margin.

Caution: No point in under sizing a separator based on what the project or client or supplier says.

Inlet Flow Surge Factors, % extra Natural GasliftOffshore Own Platform 10% 20%

From another in shallow water 20% 30%From another in deep water 30% 40%

Onshore Flat or low rolling 10% 30%Hilly 20% 40%

Liquid Most of the sources provide guidance on finding vapour flow area but are silent on Section sizing the liquid section, holdup volume or time between various level settings.

Vessel may have to accommodate pigging or random slug from incoming pipelinesbetween NLL and LAHH. Slug volume decided by pipeline transit analysis. Assume 2riser volumes, if unknown. In addition, inflow slug viz when the entire inlet volume flowis 100% liquid for 1 - 2 seconds, may have to be accommodated.

Minimum gap between liquid levels are 4" (100 mm). Long horizontal vessels require alonger gap, to avoid wave action resulting in spurious trips and alarms. Perforatedcalming baffles (plates) may help.

Liquid Holdup Time at NLL, minutes (Min /Max) Hot oil network vessels are sized based Product to a storage tank 2 5 on (1) system inventory if located below Feed to a furnace 10 15 users without a separate drain vessel Feed or reflux to a column 5 10 and (2) expansion of system load from Compressor KODs 3 5 low ambient temp to operating temp.Surge Drums 10 20Product to another plant 10 20 Compr KOD with low liquids and on on-Refrigerant Accumulator 10 15 off level control: 15 minutes (LAL to LAH)Water draw-off leg (auto/ manual) 10 8 - 24 hrs

Vertical Drum Spacing - GPSA d2Dimension KOD Mesh pad

x 12" z d 2d1" t Dy 24"/ D yt 6" d1 dz (D-d2)/2 x

In surging services, a ring (donut) type calming baffle plate, may be d3provided below LAHH level in vertical separators. Half-moon perforatedplates at the bottom along the length of a horizontal separator may help.Level tap-off points may be provided with stilling wells. d3 alternative

A side liquid outlet is preferred as it can avoid vortex effect and let sand and mud accumulate insidethe separator to be drained.

d1 alternativeHorizontal Drum Spacing x' t d2 y'There is no guideline for Horizontal drum lengths. In case lof KOD, clear distance between inlet and outlet vapour d1 x ynozzle should match the travel time of a liquid dropletfrom top of the drum to reach the liquid level. Min L =2.5D. Looking at Sep Sizing calculations at cells AK38: d3AN44, you may realize that required length is longer for Coalescer, if anyliquids at LALL. Usual design is based at LAHH.

For a mesh pad/ vane pack horizontal separator, it is usual to locate the pad 5d1 distance from inletand have minimum distance = vapour space at NLL vapour outlet.

0 - ⅓L

On large horizontal drums, a lower LALL level may result in its bottom tappinggetting located too low. For ease of fabrication, a min angle of 40° is desired. θ D/2

In horizontal sep, if sandjet or sand sucking nozzles are provided, their sizeneeds to be taken while fixing LALL.

LALL may have to provide enough head to handle vortex at liquid outlets.

Drum Sizes Dia?Standard plate sizes 2,500 - 3,000 x 6,500 mm; 796 1,114 2,069While drums can be rolled to any ID/OD, standard sizes are as below300 to 1,200 mm in steps of 100 mm 1,200 to 4,000 mm in steps of 200 mm

4,000 and above in steps of 250 mm

Nozzle Location from Tangent LinesSize, in 2 4 8 12 20 28Distance, mm 150 260 400 500 850 1,100

LG are usually available at 14", 32" and 48" span. Check with your Instrument Dept

Inlet DevicesInlet devices may be simple, a nozzle flowing against an Nozzle Half-Pipe Vaneimpingement plate or box; half pipe (bottom of pipe cut open) or vanedistributor. Simple devices are used in smaller vessels and designedproprietary devices are used in large flow large vessels.

Inlet and outlets are sized based on ρV² criteria given below, thoughsome may go by the external line sizes.

Inlet devices help reduce nozzle size. Use a simple nozzle + impingementfor smaller vessels, say 2.5 - 3' (0.75 - 0.9 m) dia; then half-pipe. If nozzle size is 2 sizes more thanexternal piping, it is OK. If bigger, use vane type distributor.

Nozzle Half-Pipe VaneDistr As mentioned in Norsok P-100, A goodFeed inlet, ρmVm² 672 1,008 4,032 inlet device reduces inlet momentumbulk separates minimizing liquid shearing into droplets and creates good vapour distribution.Nosok P-100Performance factor Nozzle Half pipe Baffle VaneMomentum reduction Poor Good Good GoodBulk separation Good Average Poor GoodPrevent re-entrainment Good Average Average GoodPrevent liquid shearing Good Average Poor GoodGood gas distribution Poor Poor Poor Good

Heating CoilHeating Coils are usually provided at the bottom of vessels, while handling light emulsions.

3 Phase SeparatorThree types in horizontal - with (1) an internal weir when oil and water (light and heavy phase) areconsiderable (2) boot when water flow is low and (3) bucket with low oil flow. (4) 1 weir type in vertical

Interphase level, viz water - oil separation layer is usually maintained constant with a level controlvalve in (1), (2) and (4). So it is easy to calculate the oil and water inventory at varying NLL/ LAH/ LAHHlevels. It gets tricky with bucket, as changes in oil or water level at say LAH or LAHH changes

This will also help minimize the ovality of the shell opening c.f. one at 90°.

interphase level. Higher than normal level can push water into the bucket or oil into water compartment.

Healthy interphase Interphase above bucket, Interphase below bucket, water gets into oil bucket oil flows into water compartment

I/P layer * Density- H2O + Oil layer * Density - Oil = Water level * Density-H2O IP level*ρH2O + (Oil level - I/P level)*ρOil = Water level*ρH2O IP level = [Water level*ρH2O - Oil level*ρOil] /(ρH2O-ρOil)

BootBoot diameter is usually 1’ (0.3m) Main Drum Dia, D m (ft) Boot Diameter, d m

<1.5 (5’) 0.3m (1’) to 0.5m (1.5’)>2.4 (8’) 0.5 m (1.5’) to 30%D

Keep LAH 250 mm (10") below main drum. Limit boot height to 1.5 m (5') by increasing diameterSizing boot-type is relatively easy as water levels are maintained in a separate vessel without muchimpact on oil level.

BucketUnlike other weir and boot types, where interphase (normal water) level is maintained by a levelcontroller, in bucket types it is decided by the relative heights of water and oil. If water is fully confinedwithin its second compartment, then its weir height governs. Similarly if oil is fuly confined to bucket,then bucket inlet height decides i/p. If water level goes up, it will push interphase high over the bucketinlet, sending water into oil bucket. Similarly high oil level will push the interphase down below bucket,letting oil go with water into the 2nd compartment. So keeping LAHH oil within the bucket and LAHHwater below its weir helps the 'dancing i/p level making calculations easy.

First enter water level with a gap of 4" or 6" (100 or 150 mm) between levels. So LAHH water will decideits weir height. Fill in similar numbers for oil levels within he bucket. Bucket being 2' to 3' (600 to 900mm wide), the gap between levels, can be 4" (100 mm). Decide a minimum gap of 8" to 12" (200 to 300mm) as the elevation of bucket bases, b. Maintain the same gap, g between bucket and water weir.Then keep changing bucket inlet height h, such that, the interphase is at NLL/LAH/LAHH water and thatof oil is neither above bucket inlet, h or below bucket base, b. Adjust bucket width to get the desiredtime and volume beween various levels. Similarly play with vessel diameter and length to get it right forwater and vapour. One or two looping should get a converged solution.

How to use the Sep Sizing spreadsheetIt is easy on vertical separators as the full cross-sectional area is available for flow. Diameter is fixed onvapour flow; liquid levels and height fixed by liquid. In Horizontal separator, liquid takes away part of thecross section and hence a number of diameter and length configuration is possible. Smaller diametervessels require thinner metal plates, weigh and cost less. Experienced users would converge on theright diameter x length usually 3 attempts. Inexperienced users like me may adopt the "shrinking envelope" method as below.

1 Start with a generous size. Have a look at the Quicksize page to decide a diameter and select a length3 times that. Fix LAHH at 50% dia. Keep 4" (100 mm) - 8" (200 mm in longer vessels) between levels.Check if assumed diameter is OK to meet all levels - that is minimum dia is (6"+4"+6"+4"+4") x 2 = 48"(1,200 mm) L = 12' (3,600 mm).

2 Now check if vapour flow area is OK. Adjust dia x LAHH to get it right. Have a look at liquid levels timesslugs etc. Slowly reduce length in steps of 6" (100 mm) and diameter in steps of 2" (50 mm) with changes in level to converge on the smallest size.

3 It is easy on a 2 Phase Seperator but gets difficult in a 3 Phase Separator. Nightmare on a bucket type.Luckily there are not many 3 Phase Sep specially bucket types. If you keep oil LAHH inside the bucketand water LAHH below its weir height, it gets easy!

Good hunting or number crunching!!

LALL

NLL LAHHLAHH

NLLHh LAL

L

NLL LAHHLAHH

HhNLL

LALL

NLL LAHHLAHH

HhNLL

Abbreviations: LALL - Very Low Liquid Level (Level Alarm Low Low); LAL - Low Liquid Level; LAH - HighLiquid Level; LAHH - Very High Liquid Level NLL - Normal Liquid Level; SDV - shutdown valve

Issues that Require Attention/ Fixing/ Improvement1 Oil Water droplet size Vs carryover correlation2 Sand collection, Jet, Washing Nozzle Spacing3 Droplet calcs differ in SI Vs FPS as per GPSA constants. Apparent error in GPSA values.

SMKumar Energy EnvRev A Oct 2010

SMKumar Energy Environment EngiRev AA Oct 2010

Revision AA ChangesSheet Cell

All All locked cells are rset to allow selectionPictures are reset for changes

Datsheet

Sep Sizing AO70:AO74

Rev AA Oct 2010

Remarks

All locked cells are rset to allow selection

Changed to maximum of level or weir height

3phase separator size 2015 vera

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