Gas Treatment Plant
Chris, Stephanie, Kyle, Mariam
Mentor: Jerry Palmer
Outline
1. Block Flow diagram
2. Mass Balance
2. Liquid Knockout
3. Sour Gas Treatments
4. Gas Dehydration
5. NGL Recovery and CO2 Removal
6. NGL Stabilization
7. Inert Removal-N2
8. Equipment Cost
9. Capital Cost
10. Revenues
11. Sample Calculations
12. Question & Answer
Block Flow Diagram
Mass Balance
Liquid Knockout
3- Horizontal Tanks and decreasing temperature and
pressure.
In a dynamic refinery environment it is important to
have the capability to compensate for a surge of
liquids and take out any non-volatile components
which will cause issues in the future separation
processes.
3 tanks are used because its the most efficient setup
for large scale processes.
5
6
Sour Gas Treatment
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Sour Gas Treatments
Liquid Scavenger
Solid Scavenger
Liquid Redox
Amine+Claus+Tail
gas
Acid Gas
Yes
Yes
Yes
Yes
Natural Gas
Yes
Yes
Yes
No
Turndown
Sensitive
Not Sensitive
Not Sensitive
Sensitive
Products Streams
Biodegradable
Liquid
Non-Hazardous
Solid
Sulfur Cake for
Fertilizer
Pure Sulfur
Operating Costs
$10/lb. of S
$3.50/lb. Sulfur
$0.15/lb. of S
Small
Equipment Costs
Low
Moderate
Moderate
High
General
Application
Guidlines
100 lb. of sulfur
per day
300 lb. of sulfur
per day
Less than 20 tons
of sulfur per day
Greater than 15
tons of sulfur
perday and
greater than 15%
H2S
8
Gases treated
Why LO-CAT II?
-System Stability
-Ease of operation and Catalyst consumption
-Chemical Cost is roughly 1/2 to 1/3 of a
Sulferox Unit
-Uses a Patented chelate system that is more
resistant to Oxidation
Gas Dehydration
Gas Dehydration & CO2 Rejection
The methods of dehydration looked into are
lean gas absorption, adsorption and membrane
separation.
Absorption
Adsorption
TEG dehydration
Mole sieve dehydration
Glycol is cost effective
Adsorbent like silica gel is expensive
For removing large quantities of water
Required for cryogenic systems which need
low moisture content
Glycol can be replaced continuously
Multiple adsorption beds are required for
continuous use.
Does not remove CO2
Removes CO2
12
PFD-003 Gas dehydration
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NGL Recovery + CO2 Removal
14
NGL Recovery
Mechanical Refrigeration Plant:
- limited to -24 to -40 F
- only 60% propane
Lean oil absorption:
- 40% ethane
- 90% propane
- 100% heavier hydrocarbons
- Heating and cooling required
- High operating cost
Turboexpander:
- 60-90% ethane
- 90-98% propane
-100% of heavier hydrocarbons
- Since high percent ethane recovery is needed, this is the
most economical way
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16
NGL Stabilization
17
NGL Stabilization
•
•
•
NGL's need to be stabilized to a point that it
can be stored and transported in nonpressurized vessels.
Enhances the safety in handling, and
improving the liquid's marketability.
Stabilizing the liquid reduces the volatility.
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19
Inert Removal-N2
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Inert Removal-N2
Available options are cryogenic distillation,
membrane separation and PSA.
Cryogenic distillation has been selected on the
basis that is very efficient for large scale
separation facilities.
Additionally because LNG is being produced in
the following stage its worthwhile to expend
the energy to process the methane.
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22
LNG Production
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LNG Production
•
•
•
LNG is produced under very low
temperatures.
Effective for transportation of natural gas
over long distances.
Safer than transporting compressed natural
gas in vehicles because LNG is comparably
low in pressure.
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Equipment Cost Estimates
Equipment
Cost
pump
$20,000 to $85,000
distillation column
$600,000
compressor
$20,000 to $1,500,000
cryo distillation column
$700,000
heat exchanger
$50,000 to $100,000
primary LNG cryo heat
exchanger
$3,000,000
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Estimated Capital Cost
Amine Treating cost for 5% acid gas removal
Dehydration cost
Compression cost (7000hp x $1400/hp)
Cryogenic NGL recovery cost
Liquid-Redox Sulfur Recovery at 5 T/d
Total cost of components
Other costs and Contingency @ 30%
Total Estimate Plant Cost
$10.0MM
$1.0MM
$9.8MM
$23.0MM
$4.0MM
$47.88MM
$14.3MM
$62.1MM
-Based on a Natural Gas Treatment Facility that processes 100 MMscfd.
-Prices based in 2008 and do not account for inflation.
Employee payroll with fringe benefits
$3.5MM/year
Revenues
•
•
•
•
•
Natural Gas: 300 Million $/year
NGL: 110 Million $/year
LNG: 50 Million $/year
Elemental Sulfur: 50,000 $/year
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Sample Calculations
SCFD to Lb/Hr conversion:
X Lb/hr = ( Y SCFD) / [ ( 24 hr/1d)*(1 lbmol/ Z Lb)*(378.827
SCF /lbmol) ]
V/n = RT/P = 378.827 @ 60F
X : lb/hr
Y : SCFD
Z: MW
X bbl = ( Y lbmol * MW lb/lbmol) / (5.615 ft^3/bbl*Z
lb/ft^3)
X= volume
Y= n moles
Z = density
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Q&A