Overview Gas Processes
-
Upload
rssankarasubramanian -
Category
Documents
-
view
469 -
download
3
Transcript of Overview Gas Processes
![Page 1: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/1.jpg)
1
Design of Natural Gas Handling Equipment
Course prepared for Offshore Oil and Gas Engineering program
ENG 8976
by Majid A. Abdi, Ph.D., P.Eng.
Faculty of Engineering and Applied ScienceMemorial University of Newfoundland (MUN)
Winter 2004
![Page 2: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/2.jpg)
2
Schedule and Evaluation Breakdown
• Instructional hours per week: 3 lecture hours; • Midterm exam: March 1st, 2004;• Evaluation:
– Assignments: 10% – Midterm: 25%– projects (term papers): 15%– Final: 50%
![Page 3: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/3.jpg)
3
Course Outline
1. Introduction2. Fluid Properties3. Inlet separator design4. Prevention of hydrate formation and dehydration of
natural gas 5. Natural gas dew point control and liquid recovery6. Natural gas transmissions systems7. Natural Gas Compression8. Natural gas measurement*9. Heat exchange equipment*10. Overview of natural gas sweetening processes*11. Natural gas transportation**Optional sections; will be covered only if time allows
![Page 4: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/4.jpg)
4
References1. Beggs H.D., Gas Production Operation, OGCI publications, 1985, ISBN: 0-930972-
06-62. Kumar S., Gas Production Engineering, Gulf Publishing, 1987, ISBN: 0-87201-577-73. Rojey A., Jaffret C., Natural Gas Production Processing Transport, Editions
Technip; (1997), ISBN: 2710806932 4. Manning F. and Thompson R., “Oil Field Processing of Petroleum, Volume 1:
Natural Gas”, Pennwell Publishing, 1991, ISBN:0-87814-343-2 5. 11th Edition GPSA Engineering Data Book, FPS and SI Versions, 1998, by Gas
Processors Suppliers Association 6. Arnold K. and Stewart M., Surface Production Operations; Volume 2; Design of
Gas-Handling Facilities, 2nd Edition, 1999, Butterworth-Heinemann, ISBN: 0-88415-822-5
7. Kohl A., Nielsen R., “Gas Purification”, 5th Edition, Pennwell, 1997, ISBN 0-88415-220-0
8. Mohitpour M., Golshan H., and Murray A. "Pipeline Design & Construction, A Practical Approach", 2nd edition, ASME Press, 2003, ISBN 0-7918-0156-X
9. Manning F. and Thompson R., Oil Field Processing of Petroleum, Volume 1: Crude,Pennwell Publishing, 1991, ISBN: 0-87814-354-8
10. Arnold K. and Stewart M., Surface Production Operations; Volume 1; Design of oil Handling Facilities, 2nd Edition, 1999, Butterworth-Heinemann ISBN: 0-88415-821-7
11. Skinner, D.R., Introduction to petroleum production: well site facilities, Gulf Publishing Co., 1981, ISBN: 0872017699
12. Brian Research and Engineering (BR&E) technical papers, 2002; see web site at: http://www.bre.com/technicalpapers/technicalpaper-home.asp
13. Instructor’s notes on personal field and design experiences
![Page 5: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/5.jpg)
5
World Natural Gas Occurrence and Production - International Gas Statistics
• Natural gas is a major world energy source.
• World natural gas reserves are estimated at 5893 TCF.
• About 72 percent of the world’s natural gas reserves are found in the Middle East and the former Soviet Union.
• Canada is a major exporter of natural gas.
![Page 6: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/6.jpg)
6
Natural Gas Origin
• Biogenic methane• Thermogenic methane • Metamorphism• Abiogenic methane
![Page 7: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/7.jpg)
7
History of Natural Gas
• Dates back to thousands years ago• Persians and Indians used it for religious
practices• Chinese used it to desalt sea water• British commercialized natural gas
![Page 8: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/8.jpg)
8
Source: BP
![Page 9: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/9.jpg)
9
World Natural Gas Reserves (2002)
Source: BP
![Page 10: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/10.jpg)
10
World Natural Gas Reserves (2002)
Source: BP
![Page 11: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/11.jpg)
11
World Natural Gas Production (2002)
Source: BP
![Page 12: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/12.jpg)
12
World Natural Gas Production (2002)
Source: BP
![Page 13: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/13.jpg)
13
World Natural Gas Consumption (2002)
![Page 14: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/14.jpg)
14
World Natural Gas Consumption (2002)
![Page 15: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/15.jpg)
15Source : BP
![Page 16: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/16.jpg)
16
Global Stranded Gas Reserves
![Page 17: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/17.jpg)
17
North American Natural Gas Reserves (2001)
![Page 18: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/18.jpg)
18
Canadian natural gas production/demand by region (2001)
![Page 19: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/19.jpg)
19
Canadian Natural Gas
![Page 20: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/20.jpg)
20
Canadian Natural Gas (2001)
![Page 21: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/21.jpg)
21
Natural Gas Value Chain
![Page 22: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/22.jpg)
22
Natural Gas Processing
![Page 23: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/23.jpg)
23
Gas Processing Facility Block Diagram
Acid Gas Management SystemsControlled Release of
emission gases to Atmosphere
SulphurSales
Sulphur Production
Natural Gas Well Gas
High Pressure
Separation
Intermittent solid removal
Water VapourRemoval -
Dehydration
NGL Recovery -Dew Point Control
(DPC)
Acid Gas RemovalHeating
SALES GAS
Cooling
Stabilization Condensate Sales
Water disposal
Water handling Facilities
Compression
LPG Recovery
(C3 & C4)
Propane and Butane
Sales
![Page 24: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/24.jpg)
24
FLUID PROPERTIESFLUID PROPERTIESCharacterization of Natural Gas and Its Products
colorless---Dry gas
colorless>50>50,000-Wet gas
Water white50-603,300-50,000>0.35Retrograde gas – gas condensate
Colored –dark brown
>402,000-3,300<0.5
Very dark –black oil
<45<2,000>0.5Associated gas from:•Low Shrinkage crude (Low GOR) –Ordinary crude•High Shrinkage Oil (high GOR) –volatile oil
COLOROAPISCF/BSTOBSTO/BRF
STOCK-TANK LIQUIDTYPICAL GORSPECTRUM OF PRODUCED SPECTRUM OF PRODUCED HYDROCARBONSHYDROCARBONS
FLUID TYPE
![Page 25: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/25.jpg)
25
Fluid Properties – Natural Gas Constituents
N2
C6+
nC5
iC5
nC4
iC4
C3
C2
C1
Abbreviation
variableFeSReservoir fines and iron sulfidevariable-Millscale or rustSolidsvariableCH3OH(MeOH), EG, etc.Methanol and glycolvariable-Corrosion inhibitorsvariableH2OFree water or brineWater vapour/Liquid
slugs
1.0-10.0ppmR-S-S-RDisulfides1.0-10.0ppmR-S-RSulfides10-1000ppmR-SHMercaptansSulphur compouns
0.2-10.0CO2Carbon Dioxide0.01-10.0H2SHydrogen sulfideAcid gasesa few ppmO2Oxygena few ppmH2Hydrogena few ppmArArgon0.01-0.1HeHelium0.2-5.0N2NitrogenInert Gases1.0-3.0-Hexanes and heavier0.1-2.0nC5H12n-Pentane
0.1-2.0iC5H12i-Pentane
0.3-7.5nC4H10n-Butane
0.3-2.5iC4H10i-Butane1.0-15.0C3H8Propane3.0-10.0C2H6Ethane59.0-92.0CH4MethaneHydrocarbons
Typical composition(volume %)
FormulaComponentsClass
![Page 26: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/26.jpg)
26
Fluid Properties – Natural Gas physical properties
• PVT behavior and equations of state • Molecular weight• Density and specific gravity• Critical pressures and temperatures • Gas compressibility factor• Viscosity• Specific heat (heat capacity)• Heating value (Wobbe number/index)• Thermal conductivity
![Page 27: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/27.jpg)
27
Fluid Properties – Equations of State
• Behavior of ideal gas • Behavior of a real (non-ideal) gas• Compressibility factor approach• Important equations of state
Van der WaalsBenedict-Webb-Rubin (BWR)Saove-Redlich-Kwang (SRK)Peng-Robinson (PR)Virial
![Page 28: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/28.jpg)
28
Principal Equation of States
![Page 29: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/29.jpg)
29
Fluid Properties – Molecular Weight – Mole concept
Weight of a mole of any substance Different units in Imperial, SI and CGS systemsMoles = Weight of a gas component divided by its molecular weightAverage molecular weight =
]).([ NN MWyMW ∑=
![Page 30: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/30.jpg)
30
Fluid Properties – Density and Specific Gravity
• Density = mass of a unit volume (lb/ft3 or kg/m3)
• S = MW/29 (for gases)
or
• S.G.= density of liquids/density of pure water @ 60oF
• oAPI =141.5/S.G. -131.5 (for liquid hydrocarbons such as crude oil)
TZSP
g 7.2=ρTZ
PMWg
)(093.0=ρ
![Page 31: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/31.jpg)
31
Fluid Properties – Critical Pressures and Temperatures
• Critical temperature= the maximum temperature at which the component can exist as a liquid
• Critical pressure= vapour pressure of a substance at its critical temperature
• Beyond critical temperature and pressure there is no distinction between a liquid and a gas phase
PCN and TCN from Figure 23-2 GPSAPPC = Σ yNPCN and TPC = Σ yNTCN
PPC = 709.604 – 58.718 S
TPC = 170.491 + 307.344 SThomas et al. equation
![Page 32: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/32.jpg)
32
Physical Property Tables
![Page 33: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/33.jpg)
33
Physical Property Tables
![Page 34: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/34.jpg)
34
Fluid Properties – Gas Compressibility Factor
• Standing-Katz compressibility charts (Figures 23-3, 23-4, and 23-5 GPSA)
• Brown-Katz-Oberfell-Alden charts (Figures 23-7, 23-8, and 23-9 GPSA)
• Acid gas content consideration by Wichert-Aziz correction factors
ε from Figure 23-10 GPSA• Compressibility from equations of state
)1(
'''
BBTTPPandTT
PC
PCPCPCPCPC −+=−=
εε
![Page 35: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/35.jpg)
35
Compressibility charts Brown-Katz-Oberfell-Alden Z charts
Standing-Katz compressibility charts
![Page 36: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/36.jpg)
36
Fluid Properties – Gas Viscosity
• Carr et al. correlation (Fig. 23-32 and 23-33 GPSA)• Viscosity of gas mixture from single component data:
• Lee et al. for natural gas:
• GPSA charts – Fig.s 23-30 through 23-38• Dean and Stiel method
∑
∑
=
== n
NNN
n
NNNgN
g
MWy
MWy
1
5.0
1
5.01
1
µµ
XyandMWTXTMW
TMWKwhereXK ygg
2.04.201.0/9865.319209
)02.04.9(10,)exp(5.14
−=++=++
+==
−
ρµ
[ ]
9/8Pr
5Pr
9/5
Pr5
Pr3/22/1
6/1
)10(0.34,5.1
,0932.01338.0)10(8.166,5.1;)(
4402.5
TTforand
TTforPMWy
T
g
gPCNN
PC
−
−
=≤
−=>=∑
ξµ
ξµξ
![Page 37: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/37.jpg)
37
Viscosity Charts
![Page 38: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/38.jpg)
38
Fluid Properties – Specific Heat
• Definition: amount of heat required to raise the temperature of a unit mass of a substance through unity
• Cp and Cv and their relationships (Maxwell’s equation)
• Cp determination– Hankinson’s gravity C op = A + B.T + C.S + D.S2 + E(T.S) + F.T2
– Kay’s mixing rule
• Cp of natural gas mixture, pressure corrections (GPSA Figure 13-6 and Kumar’s Book – Table 3-3, Figures 3-17 and 3-19)
RCCgasesidealforvPTPTCC vp
T
vvp =−
∂∂∂∂
−=−)/()/( 2
∑=
=n
N
opNN
op CyC
1
![Page 39: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/39.jpg)
39
Heat Capacity Data
![Page 40: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/40.jpg)
40
Fluid Properties – Heating Value/Wobbe Index
• Definitions:– Gross Heating Value (GHV) or Higher Heating Value
(HHV):Total energy transferred as heat in an ideal combustion reaction at a standard temperature and pressure in which all water formed appears as liquid
– Net Heating Value (NHV) or Lower Heating Value (LHV):Totalenergy transferred as heat in an ideal combustion reaction at a standard temperature and pressure in which all water formed appears as vapour
• Heating value determination: Hv = Σ yNHvN
• Wobbe Index: WO=HHV /S1/2
![Page 41: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/41.jpg)
41
Fluid Properties – Thermal conductivity
• Significance of thermal conductivity – Heat transfer calculations and heat exchanger (line heater, shell and tube, air cooler, etc.) design
• Determination of thermal conductivity – gas and liquid (GPSAFig.s 23-40 through 23-45)
• Lenoir et al. pressure corrections• Gas mixture thermal conductivity
∑∑=
).().(
3
3
NN
NNNm MWy
MWkyk
![Page 42: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/42.jpg)
42
Thermal conductivity Charts
![Page 43: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/43.jpg)
43
Thermal conductivity Charts (cont.)
![Page 44: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/44.jpg)
44
Phase Behavior - Fundamentals
• Single component fluid• Two component fluid• Multi-component fluid• Phase diagrams (envelopes)
– Pressure-Temperature-Volume (PVT)– Pressure-Temperature (PT)– Pressure composition – Composition-composition
• Phase ruleN=C-P+2
![Page 45: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/45.jpg)
45
Phase Behavior – Single Component Systems
B
A
CD
a b c de h
Dense Fluid region-supercritical fluid
gf
• Phase Equilibrium – gas-liquid– gas-solid– Liquid-solid
• Triple point • Critical point
![Page 46: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/46.jpg)
46
Phase Behavior: Two-Component Systems
• Concept of phase envelope
• Equilibrium lines– Bubble point– Dew point
• Critical point• Cricondentherm• Cricondenbar• Rertrograde phase
change
Pres
sure
Cricondenbar
Cricondentherm
Dew-Point L
ine
Bubble
-Poin
t Line
Vapo
urpr
essu
re
of p
ure
A
Vapour pressure
of pure B
C
a bd e
h
j
klPC
TC
Two component phase envelop
90% va
p’d
g
f
Temperature
![Page 47: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/47.jpg)
47
Phase Behavior: Multi-Component Systems
C
Condensate reservoirOil reservoir
Gas reservoir
A
A’
B
B’
C
C’
D
D’
E
E’
Temperature
Pres
sure Two-Phase Region
(Gas+Liquid)
Cric
onde
nthe
rm
Wet Gas
Dry
Gas
• Full wellstream• Source of phase
diagrams• Quantitative phase
behavior • Phase behavior in
separators
![Page 48: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/48.jpg)
48
Phase Behavior: Vapour-Liquid Equilibria
• Thermodynamic criteria for equilibrium-equality of fugacities: fN,v= fN,l
• Equilibrium ratio (K values): K=yN / xN
• Equilibrium calculations– Equilibrium flash:
– Bubble point: ΣyN =Σ zN . KN = 1.0Σ zN . KN > 1.0 guarantees vapour is
present– Dew point: ΣxN =Σ zN / KN = 1.0
Σ zN / KN > 1.0 guarantees liquid is present
N
NNN KLV
FKV+
=)//(1
V, yN
F, zN
L, xN
A gas-liquid flash separator
![Page 49: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/49.jpg)
49
Phase Behavior: Water Hydrocarbon Systems• Water and hydrocarbons are insoluble in liquid phase• Problems with water saturated gas
– Excessive pressure drop – Plugging due to ice and hydrate formation– Sever corrosion in acid and sour gas lines
• Water content of natural gas – McKetta and Wehe charts: Fig. 20-3, GPSA– Robinson et al. correlation for sour gases: Fig.s 20-10 and 20-
11, GPSA– Campbell charts: W = yhc Whc + yCO2 WCO2 + yH2S WH2S and
Fig.s 20-8 and 20-9, GPSA)– Equation of state methods; SRK, PR and commercial process
simulators (e.g. HYSYS, ASPEN, PROSIM, PROII, AMSIM, AQUASIM, SSI, DESIGNII, PROCESS, etc.)
![Page 50: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/50.jpg)
50
Phase Behavior: Water Hydrocarbon Systems–Natural Gas Hydrates
• Gas hydrate - pipeline trouble maker or ?
• Prediction of hydrate formation conditions
– Katz Gas gravity– Wilson-Carson-Katz equilibrium-
constant method – Baillie and Wichert method– Equation of state methods
• Comparison of techniques to predict hydrate formation conditions
![Page 51: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/51.jpg)
51
Water Hydrocarbon Systems: Overall Phase Behavior of Natural Gas- Hydrates Systems
Wat
er
Dew
-poi
nt
Curv
e
Hydr
ocar
bon
Phas
e En
velo
pe
Hydrate Formation Curve
Lhc+Lw+G+H Lhc+Lw+G
Lw+G
G
Pres
sure
B. High Water Content
Hydr
ocar
bon
Phas
e En
velo
pe
Lhc+Lw+G+H Lhc+Lw+G Lhc+G
Pres
sure
Wat
er
Dew-
poin
t cC
urveHy
drat
e Fo
rmat
ion
Curv
e
G
Lw+G
A. Normal Case
A
Temperature Temperature
![Page 52: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/52.jpg)
52
Phase Behavior: Carbon Dioxide Frost Point
• Significance of CO2 freezing- design of turbo-expansion facilities and cryogenic NGL recovery systems
• CO2-methane equilibrium (Liquid-solid-vapour systems) (see Ref.1, also Fig.s 25-5 and 25-6 of GPSA data book)
• Natural gas-CO2 systems (see Ref. 1)
• Predicting CO2 formation conditions (GPSA charts vs. process simulators)
![Page 53: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/53.jpg)
53
Natural Gas Properties/Phase Behavior and
Scope of Natural Gas Field Processing• Process objectives
– Transportable gas– Salable gas– Maximized condensate (NGL) production
• Gas type and source– Gas-well gas– Associated gas– Gas condensate
• Location and size of the field– Remoteness– Climate– size
![Page 54: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/54.jpg)
54
Scope of Natural Gas Field Processing: Process objectivesProcess objectives
• Transportable gas– Hydrate formation– Corrosion– Excessive pressure drop (two-phase flow)– Compression requirement (dense phase flow)
• Salable gas– Sales quality-pipe line spec. (see Fig. 2-4, GPSA)– Heating value-inert gas and condensate recovery
• Maximized condensate (NGL) production– Maximizing crude production– Retrograde condensate gas processing– Inherent value of NGL
![Page 55: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/55.jpg)
55
Scope of Natural Gas Field Processing: Type and Source of Natural GasType and Source of Natural Gas
1. Gas-well gas– Wet or dry– Lean or rich– Sour or sweet
2. Associated gas– Enhanced oil recovery (EOR)– Enhancement crude production
3. Gas condensate– Pressure maintenance– Gas cycling operations
![Page 56: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/56.jpg)
56
Scope of Natural Gas Field Processing: Filed Location, Size, and OperationFiled Location, Size, and Operation• Remoteness
– Offshore vs. onshore (land) reservoirs– Platform design– Floating gas processing (a new concept)
• Climate– Design consideration for harsh environment– Cold vs. warm– Dry vs. humid
• Size– Reservoir capacity– Production rate: small vs. large
• Gas handling facilities operations
![Page 57: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/57.jpg)
57
GAS AND LIQUID SEPARATIONGAS AND LIQUID SEPARATION
•• Purpose, principles and terminologyPurpose, principles and terminology• Separation equipment- common
components • Types of separators • Separation principles • Separator design• Factors affecting separation • Operational Problems
![Page 58: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/58.jpg)
58
Gas and Liquid Separation: Separation Equipment- Major Parts
A - Primary Separation
B - Gravity Settling
C - Coalescing
D - Liquid Collecting
![Page 59: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/59.jpg)
59
Gas and Liquid Separation - Types of Separators
• Gravity (vertical vs. horizontal)• Centrifugal• Filter coalescing• Impingement• Comparison of separators –
advantages vs. disadvantages
![Page 60: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/60.jpg)
60
Gas and Liquid Separation: Separation Equipment- vertical separator
Source: Natco
![Page 61: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/61.jpg)
61
Gas and Liquid Separation: Separation Equipment- Horizontal separators
![Page 62: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/62.jpg)
62
Gas and Liquid Separation: Separation Equipment, Two-Barrel (Double-Tube) horizontal separator
![Page 63: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/63.jpg)
63
Gas and Liquid Separation: Separation Equipment- horizontal filter separator
Filter elements
![Page 64: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/64.jpg)
64
Gas and Liquid Separation: Separation Equipment- mist eliminator arrangement
![Page 65: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/65.jpg)
65
Gas and Liquid Separation: Separation Equipment-Vane (radial/axial) mist extractor arrangement
Vertical Radial Flow (VRF) separator
A
BC
D
Downcomer
J=ρg .Vt2 = 20 lb/(ft.sec2)
NatcoTM radial vanes
![Page 66: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/66.jpg)
66
Gas and Liquid Separation: Separation Equipment- Centrifugal separator
![Page 67: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/67.jpg)
67
Gas and Liquid Separation: Separation Equipment- Swirl/cyclonic separators
Porta-Test Whirlyscrub ITM
Source: Natco
![Page 68: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/68.jpg)
68
Gas and Liquid Separation –Separation principles
]2
[2
gV
ACF tDD ρ= Drag force
Stock’s termonalvelocity for:
Re < 1.0µ
26 .).(1078.1 mt
dGSV
∆×=
−
Re for actual natural gas and crude operations are much larger than 1.0, therefore the following equations should be iteratively used to calculate the terminal velocity and drag coefficient:
34.03242/1 ++=
ReReCD
2/1])[(0119.0D
m
g
glt C
dVρρρ −
=
![Page 69: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/69.jpg)
69
Gas and Liquid Separation –Separation principles: Terminal Velocity/Residence Time calculations
• Terminal velocity iterative calculations:
1. Start calculating CD using:
2. Calculate Re as:
3. Calculate new values for CD :
4. Calculate new values for CD :
5. Go to step 2 and iterate until CD,new – CD,old ≤ 0.001
• Residence time definition: Effective vessel volume/flow rate or:
t = V /Q
2/1])[(0204.0 mg
glt dV
ρρρ −
=
µρ tmg Vd
Re 0049.0=
34.03242/1 ++=
ReReC D
2/1])[(0119.0D
m
g
glt C
dVρρρ −
=
![Page 70: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/70.jpg)
70
Gas and Liquid Separation – Separator Design
• Gas capacity• Liquid capacity• Gas Capacity Calculations: Souders-Brown’s
Technique• Vessel design considerations• Separator design using manufacturers
separator performance charts• Computer based techniques -
Computational Fluid Dynamics (CFD), etc.
![Page 71: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/71.jpg)
71
Gas and Liquid Separation – Sizing Equations• Horizontal separator
– Gas Capacity:
Or: , where, from Fig. 4.10 Ref.8
– Liquid Capacity:
– Seam to seam length: Lss = Leff + d/12 for gas capacity and Lss = 4/3 Leff for liquid capacity
• Vertical Separators– Gas capacity:
– Or: , where K is defined as above and found from Fig. 4.10 Ref. 8
– Liquid capacity:
– Seam-to-seam length:
2/1
420
−
=
m
D
gl
ggeff d
CP
TZQdL
ρρρ
=
PTZQ
KdL geff 42
2/1
−= D
gl
g CKρρ
ρ
7.02 lr
effQt
Ld =
2/1
2 040,5
−
=
m
D
gl
gg
dC
PTZQ
dρρ
ρ
=
PTZQ
Kd g4202
12.02 lr Qthd =
1240......;........
1276 ++
=+
=dhLorhL ssss
![Page 72: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/72.jpg)
72
g
glSBt KV
ρρρ −
=
Gas and Liquid Separation: Sizing Equations-Souders-Brown Technique
2/1])[(0119.0D
m
g
glt C
dVρρρ −
=
Terminal Velocity Equation
Souders-Brown Equation
0.4-0.5(L/10)0.565
0.40-0.50
0.18-0.35
0.12-0.24
API Recom’d. KSB, (ft/sec.)
-Other lengths
0.38 with mist extractor10Horizontal
0.18 without and 0.3 with mist extractor
10
0.12 without and 0.2 with mist extractor
5Vertical
Most commonly used KSBValue(ft/sec.)
Height, H or Length, L (ft)
Separator type
API Spec. 12 J (1989) Recommendations for KAPI Spec. 12 J (1989) Recommendations for KSBSB valuesvalues
![Page 73: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/73.jpg)
73
Gas and Liquid Separation: Vessel design considerations
• Liquid residence time: 2-4 min• Liquid-gas interface (minimum
diameter/height): 6 ft. vertical height; 26 in. horizontal diameter
• Gas specification: 0.1 gal/MMscf• Liquid re-entrainment: API Spec. 12J• Pipe connections:• Fabrication cost• Optimum length to diameter (L/D) or
aspect ratio
2 to 410-20
1 to 220-30
1Above 35
API recom’ndLiquid retention
time (min)
Oil gravityoAPI
API Spec. 12J (1989API Spec. 12J (1989)
![Page 74: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/74.jpg)
74
Gas and Liquid Separation: Separator Design-manufacturers charts
Source: Natco
![Page 75: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/75.jpg)
75
Gas and Liquid Separation: Separator Design-CFD modelling
![Page 76: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/76.jpg)
76
Gas and Liquid Separation: Factors Affecting Separators Performance
• Operating and design pressure and temperature
• Fluid composition and properties (density, Z-factor, etc.)
• Fluid (gas and liquid) flow rates
• Degree of separation• Two vs. three phase• Gas vs. oil - sand and solids?• Surging/slugging tendencies• Foaming and Corrosive
tendencies• Offshore floating vs. land base
static facilities
Sway Surge
Heave
Roll PitchYaw
◘◘Articulated tower
◘◘Guyed tower platforms
◘◘Tension-leg platforms
◘◘◘Semi-submersibles
◘◘◘◘Single point anchored
tanker
YawPitchRollHeaveSwaySurge
Angular motionLinear motionMotion
![Page 77: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/77.jpg)
77
Gas and Liquid Separation: Operations
• Potential Problems– Foaming– Fouling –
• Solid/sand deposition • Hydrate, paraffin, wax
– Corrosion– Liquid carryover and gas blowby– Flow variations
• Maintenance• Troubleshooting
![Page 78: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/78.jpg)
78
Gas and Liquid Separation: Operations-Troubleshooting
1. Low liquid level2. High liquid level3. Low pressure in separator4. High pressure in separator5. All the oil going out gas line6. Mist going out gas line7. Free gas going out oil valve8. Gas going out water valve on three-phase9. Too much gas going to tank with the oil10.Condensate and water not separating in 3-phase11.Diaphragm operated dump valve not working
![Page 79: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/79.jpg)
79
NATURAL GAS DEHYDRATIONNATURAL GAS DEHYDRATION
• Introduction- purpose of gas dehydration• Pipeline specification• Hydrate prevention• Methods of dehydration
– Absorption dehydration using glycol – Solid bed adsorption– Expansion refrigeration (LTX units)
• Design techniques• Operations of dehydration facilities
![Page 80: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/80.jpg)
80
Natural Gas Dehydration- Hydrate Prevention
• Line heating and Low Temperature Exchange Units (LTX
• Inhibition by additives– Types and selection of additives– Inhibitor requirements––– Prediction of inhibitor requirementsPrediction of inhibitor requirementsPrediction of inhibitor requirements––– Injection techniquesInjection techniquesInjection techniques––– Operations and troubleshootingOperations and troubleshootingOperations and troubleshooting
![Page 81: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/81.jpg)
81
Natural Gas Dehydration-Hydrate Prevention
Typical Glycol injection system
![Page 82: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/82.jpg)
82
Natural Gas Dehydration- Hydrate Prevention
• Inhibition by additives––– Types and selection of additivesTypes and selection of additivesTypes and selection of additives– Process consideration– Injection techniques ––– Prediction of inhibitor requirementsPrediction of inhibitor requirementsPrediction of inhibitor requirements––– Operations and troubleshootingOperations and troubleshootingOperations and troubleshooting
![Page 83: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/83.jpg)
83
Natural Gas Dehydration- Hydrate Prevention: Inhibitor Requirements
• Inhibition by additives––– Types and selection of additivesTypes and selection of additivesTypes and selection of additives––– Process considerationProcess considerationProcess consideration––– Injection techniques Injection techniques Injection techniques – Prediction of inhibitor requirements
• Hammerschmidt’s equation• Computer simulation
––– Operations and troubleshootingOperations and troubleshootingOperations and troubleshooting
3210662MW
233540004000KH
MethanolDEGEG
HKMWdMWdW
+=
))(()100)()((
![Page 84: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/84.jpg)
84
Natural Gas Dehydration- Hydrate Prevention: Operations and Troubleshooting
• Operations– Vapour losses– Corrosion– Glycol losses– Glycol-water-oil separation
• Troubleshooting– Preventing freeze-offs– Improving Glycol-Condensate Separation
![Page 85: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/85.jpg)
85
Natural Gas Dehydration- Glycol Absorption
• Advantages over other methods of dehydration:– Solid desiccant– Expansion refrigeration (LTS or LTX units)
• Choice of glycol (EG and DEG vs. TEG)• Process description and elements• Design methods• Process operations
![Page 86: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/86.jpg)
86
Natural Gas Dehydration- Glycol AbsorptionSource: Natco
A typical glycol absorption process
![Page 87: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/87.jpg)
87
Process Elements:1.1. Inlet scrubberInlet scrubber2.2. Absorber (glycol contactor)Absorber (glycol contactor)3.3.3. Flash tankFlash tankFlash tank4.4.4. FiltersFiltersFilters5.5.5. Glycol pumpGlycol pumpGlycol pump6.6.6. Surge tankSurge tankSurge tank7.7.7. Heat exchangersHeat exchangersHeat exchangers8.8.8. Regeneration system (tower and Regeneration system (tower and Regeneration system (tower and reboilerreboilerreboiler)))9.9.9. InstrumentationInstrumentationInstrumentation
Natural Gas Dehydration- Glycol Absorption
Natco bubble cap
![Page 88: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/88.jpg)
88
Process Elements:1.1.1. Inlet scrubberInlet scrubberInlet scrubber2.2.2. Absorber (glycol contactor)Absorber (glycol contactor)Absorber (glycol contactor)3.3. Flash tankFlash tank4.4. FiltersFilters5.5. Glycol pumpGlycol pump6.6. Surge tankSurge tank7.7.7. Heat exchangersHeat exchangersHeat exchangers8.8.8. Regeneration system (tower and Regeneration system (tower and Regeneration system (tower and reboilerreboilerreboiler)))9.9.9. InstrumentationInstrumentationInstrumentation
Natural Gas Dehydration- Glycol Absorption
![Page 89: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/89.jpg)
89
Process Elements:1.1.1. Inlet scrubberInlet scrubberInlet scrubber2.2.2. Absorber (glycol contactor)Absorber (glycol contactor)Absorber (glycol contactor)3.3.3. Flash tankFlash tankFlash tank4.4.4. FiltersFiltersFilters5.5.5. Glycol pumpGlycol pumpGlycol pump6.6.6. Surge tankSurge tankSurge tank7. Heat exchangers8. Regeneration system (tower and reboiler)9. Instrumentation
Natural Gas Dehydration- Glycol Absorption
![Page 90: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/90.jpg)
90
• Required information– Inlet gas flow rate, T and P and
composition– Required water dew point– Available utilities– Safety/environmental
regulations
• Required TEG reconcentration
• Process flow sheeting (M&EB)
• Equipment sizing
Natural Gas Dehydration- Glycol Absorption: Design Guidelines
Equipment Specification
Tables from NatcoNatco
![Page 91: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/91.jpg)
91
Equipment sizing:• Contactor
– Height (2 to 3 theoretical stages or GPSA Figures 20-53 to 20-58)
– Diameter (Sauders-Brown)• Pump (70-80% mechanical efficiency
Pump BHP=(0.000012) (gph) (psig)
Natural Gas Dehydration- Glycol Absorption: Design Guidelines
![Page 92: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/92.jpg)
92
Regeneration package• Flash Tank• Stripping column
– Three theoretical stages
– Diameter: 9.gpm0.5
• Reboiler– Duty: 1500.gph– Temp.: 370-390oF– Firetube flux: 6000-
8000 Btu/hr.ft2
Natural Gas Dehydration- Glycol Absorption: Design Guidelines
![Page 93: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/93.jpg)
93
• Heat Exchangers– Reflux condenser– Lean-rich glycol HX– Lean glycol cooler
Natural Gas Dehydration- Glycol Absorption: Design Guidelines
![Page 94: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/94.jpg)
94
Natural Gas Dehydration- Glycol Absorption: Operations
Contactor• Inlet gas flow rate• Inlet gas T and P• Len TEG T and
concentration• TEG flow rate• Contactor T
<200 (pefer 180)TEG entering pump380-400 (prefer 380)Reboiler
210Top of stripping column
300-350TEG to stripping column
100-150 (prefer 150)TEG to filters100-150 (prefer 150)TEG to flash tank
5-15 warmer than inlet gas
TEG to contactor80-100Inlet gas
Tempearture (oF)Process location
![Page 95: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/95.jpg)
95
• Regenerator– Reboiler T– Stripping gas– Column T
Natural Gas Dehydration- Glycol Absorption: Operations
Drizo® Process
![Page 96: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/96.jpg)
96
• Glycol care– Oxygen– Thermal decomposition– Low pH– Salt contamination– Liquid HC– Sludge accumulation– Foaming
Natural Gas Dehydration- Glycol Absorption: Operations
![Page 97: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/97.jpg)
97
• Glycol pump• Sour gas • Startup/shutdown
Natural Gas Dehydration- Glycol Absorption: Operations
![Page 98: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/98.jpg)
98
Preventive maintenance– Daily – Weekly– Monthly– Annual inspections
Natural Gas Dehydration- Glycol Absorption: Operations
![Page 99: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/99.jpg)
99
Natural Gas Dehydration- Glycol Absorption: Troubleshooting
• High exit gas dew-point• High glycol loss (should
be < 0.1 gal/MMscf)– Loss from contactor– Loss from stripping column– Loss from separator– Leaks and spills
• Glycol contamination• Poor glycol regeneration
• Low glycol circulation• High pressure drop across
contactor• High stripping column
temperature• High reboiler pressure• Firetube fouling/ hotspots/
burnout• Low reboiler temperature• Flash separator failure
![Page 100: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/100.jpg)
100
Natural Gas Dehydration- Solid desiccants
Example Solid Desiccant Dehydrator Twin Tower System (Source: GPExample Solid Desiccant Dehydrator Twin Tower System (Source: GPSA)SA)
![Page 101: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/101.jpg)
101
Natural Gas Dehydration- Solid desiccants
Natco’s solid desiccant beds
![Page 102: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/102.jpg)
102
Natural Gas Dehydration- Solid desiccants: Design• Allowable gas superficial velocity• Pressure drop - vessel diameter: Ergun’s eq.
• Cycle time (6-8 hours)• Bed length: Saturation Zone (LS) and Mass Transfer Zoneheights (LMTZ)
)(4
))((13.0 2 densitybulkDSLand
CCWS s
sTss
rs π
==
2VCVBLP ρµ +=
∆
0.0002100.2381/16” extrudate
0.0001360.1521/16” bead
0.0001240.07221/8” extrudate
0.00008890.0561/8” bead
CBParticle type Allowable Velocity for Mole Sieve Dehydrator
![Page 103: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/103.jpg)
103
Natural Gas Dehydration- Solid desiccants: Design (cont.)
• Length of mass transfer zone LMTZ = (V/35)0.3 (Z)
• Bed regeneration– Heat duty– Regeneration gas rate
• General comments ondsing
![Page 104: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/104.jpg)
104
Natural Gas Dehydration- Solid desiccants: Operations
• Desiccant installation• Startup• Switching• Operating data• Energy conservation
![Page 105: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/105.jpg)
105
Natural Gas Dehydration- Solid desiccants: Troubleshooting
• Proper design-Design considerations
• Bed contamination• High Dew point• Premature Breakthrough
![Page 106: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/106.jpg)
106
Natural Gas Dehydration- Refrigeration and Membrane
A typical JT unit for water and NGL removal (source: Natco)
Manufacturer selection guide (source: Natco)
Membrane systems (Source: Air Products)
![Page 107: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/107.jpg)
107
Natural Gas Dehydration- Process Selection
• Dehydration methods advantages and disadvantages– TEG (glycol dehydration)– Solid desiccants– Low temperature– Membranes
• Selection recommendations
![Page 108: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/108.jpg)
108
NATURAL GAS LIQUID RECOVERYNATURAL GAS LIQUID RECOVERY
• Why NGL recovery?• NGL components and specifications• Introduction to low temperature processes• Processing objectives
– Transportable gas– Sales gas– Maximum NGL recovery
• Value of NGL• Liquid Recovery Porcesses
![Page 109: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/109.jpg)
109
Natural Gas Liquid Recovery- Processes
• Refrigeration• JT-Valve expansion (LTS)• JT-Turbine Expansion• Oil absorption• Solid bed adsorption
Hyd
roca
rbon
Ph
ase
Enve
lope
Liquid
Gas
Pres
sure C B A
C’’
C’
RefrigerationInterchange JT and
Expander
Expander JT
Gas-Gas HX
Temperature
![Page 110: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/110.jpg)
110
Natural Gas Liquid Recovery- Processes: Joule-Thompson (JT) Valve Expansion
Hyd
roca
rbon
Ph
ase
Enve
lope
Liquid
Gas
Pres
sure
C
B A
C’’
C’
RefrigerationInterchange JT and
Expander
Expander JT
Gas-Gas HX
A simplified JT Expansion Process
Temperature
![Page 111: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/111.jpg)
111
Natural Gas Liquid Recovery- Processes: LTS Units
![Page 112: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/112.jpg)
112
Natural Gas Liquid Recovery- Processes: LTS Units
![Page 113: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/113.jpg)
113
Natural Gas Liquid Recovery- Processes: Refrigeration
![Page 114: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/114.jpg)
114
Natural Gas Liquid Recovery- Processes: Refrigeration
![Page 115: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/115.jpg)
115
Natural Gas Liquid Recovery- Processes: Oil absorption
Flow Diagram of a Refrigerated Lean Oil Absorption Process
![Page 116: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/116.jpg)
116
Natural Gas Liquid Recovery- Processes: JT Turbine Expansion
Hyd
roca
rbon
Ph
ase
Enve
lope
Liquid
Gas
Pres
sure
C
B A
C’’
C’
RefrigerationInterchange
JT and Expander
Expander JT
Gas-Gas HX
Temperature
A Simplified Turbo Expansion Flow Diagram
![Page 117: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/117.jpg)
117
Natural Gas Liquid Recovery- Processes: JT Turbine Expansion
Conventional Turbo-expansion System
![Page 118: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/118.jpg)
118
Natural Gas Liquid Recovery- Processes: JT Turbine Expansion
Residue Recycle (RR) Turbo-expansion Process
![Page 119: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/119.jpg)
119
Natural Gas Liquid Recovery- Processes: JT Turbine Expansion
![Page 120: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/120.jpg)
120
Natural Gas Liquid Recovery- Processes: JT Turbine Expansion
![Page 121: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/121.jpg)
121
Natural Gas Liquid Recovery- Processes: JT Turbine Expansion
![Page 122: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/122.jpg)
122
Natural Gas Liquid Recovery- Processes: Mixed Refrigerant
![Page 123: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/123.jpg)
123
Natural Gas Liquid Recovery- Processes: Solid Bed Adsorption
Solid Bed Adsorption Dew Point Control Units
![Page 124: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/124.jpg)
124
Natural Gas Liquid Recovery- Process Selection
• NGL content of the gas– Low: expander process– High: external refrigeration
• Inlet gas pressure– High: LTS – Low: Turbine expansion or refrigeration
• Gas flow rate– Low: simple valve JT unit, solid adsorption or
membranes– Large: more complex plants
• Location (offshore, onshore, or remote areas)
![Page 125: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/125.jpg)
125
Natural Gas Liquid Recovery - Process Design
• Process flowsheeting/simulation – EOSs (SRK, PR, etc.)– Software packages (BR&E PROSIM®, Hyprotech
HYSYS®, Aspen®, Chemshire Design II®, SSI PROCESS® and PRO/II® etc.)
• Equipment selection– HXs– Towers– Turboexpanders– Pumping and storage
![Page 126: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/126.jpg)
126
Natural Gas Liquid Recovery – Equipment Selection: Heat Exchangers
Basic Components of a Three Stream Counterflow Brazed Aluminum Heat Exchanger Typical Fin Arrangements for Gas/Gas
Exchanger
![Page 127: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/127.jpg)
127
Natural Gas Liquid Recovery – Equipment Selection: Towers, Pumps, and Storage
![Page 128: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/128.jpg)
128
Natural Gas Liquid Recovery – Refrigeration Cycle
Simple Cycle
• Process flow diagram
• Vapour compression P-H diagram
1. Expansion
2. Evaporation
3. Compression
4. Condensation
![Page 129: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/129.jpg)
129
Natural Gas Liquid Recovery – Refrigeration Cycle
![Page 130: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/130.jpg)
130
Natural Gas Liquid Recovery – Refrigeration Cycle: Single, vs Multistage Systems
![Page 131: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/131.jpg)
131
Natural Gas Liquid Recovery – Refrigeration Cycle: Single, vs Multistage Systems
![Page 132: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/132.jpg)
132
Natural Gas Liquid Recovery – Refrigeration Cycle: Refrigerant Cascading
![Page 133: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/133.jpg)
133
![Page 134: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/134.jpg)
134
Natural Gas Liquid Recovery – Design and Operating considerations
• Oil removal
• Liquid surge and storage
• Vacuum systems (air leaks and corrosion)
•Vacuum considerations
![Page 135: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/135.jpg)
135
Natural Gas Liquid Recovery – Design and Operating considerations
• Material of construction
no copper in presence of ammonia and sulfur compounds
Steel is preferred (CS down to -20oF)
Aluminum alloy and SS for very low Ts
ANSI B31.3 and B31.5 design codes
• Refrigeration purity
Lube oil
Light and heavy ends
Process fluid leak
Air leak and humidity (use drier or methanol wash/purge)
![Page 136: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/136.jpg)
136
Natural Gas Liquid Recovery – Refrigeration Compressors
Compressor types
• Centrifugal (>450 HP)
• Reciprocating (higher efficiency, multistage)
• Screw (high compression ratios up to 10, less noise)
• Rotary (low capacity)
![Page 137: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/137.jpg)
137
Natural Gas Liquid Recovery – Mixed refrigerant
![Page 138: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/138.jpg)
138
• Kettle type Allowable refrigerant load in lb/hr per ft3 vapor space =
• Plate fin
Natural Gas Liquid Recovery – Refrigeration Chillers
VL
VFSρρ
σρ−)869.0(
)3980)(.)(.(
![Page 139: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/139.jpg)
139
Natural Gas Liquid Recovery –Refrigeration Control System
• Level displacer-type
internal float
differential pressure
• PressureCompressor suction and discharge
• Temperature
Chiller (by controlling compressor suction pressure)
Low ambient
![Page 140: Overview Gas Processes](https://reader033.fdocuments.us/reader033/viewer/2022051515/54ea707d4a7959e7158b5041/html5/thumbnails/140.jpg)
140
• High Compressor Discharge Pressure• High Process Temperature• Inadequate Compressor Capacity• Inadequate Refrigerant Flow to Economizer or Chiller
Natural Gas Liquid Recovery – Refrigeration Operations and trouble shooting