Embed Size (px)
Citation preview
NATURAL GAS HYDRATE TRANSPORTATIONDavid Mannel
David Puckett
CONTENTS
Hydrate Synthesis
Hydrate Transportation
Hydrate Dissociation
Production Summary
LNG Cost Estimation
Economic Comparison
HYDRATE SYNTHESIS
HYDRATE SYNTHESIS
Water content in hydrate slurry is frozen to form hydrate-ice blocks at 241 K. Blocks are then depressurized to 1 atm and handled in solid form.
PC
Fresh Water Supply
Recycled Water
Purified Gas Supply
Recycled Gas
Reactor
Decanter
Hydrate-Water Slurry
Freezing Basin
Hydrate-Ice Blocks
Flare Gas
AbsorptionRefrigerator
PropaneRefrigerator
ReducedWaterSlurry
1 mtpa, 750 psia, 388 K
6.47 mtpa, 750 psia, 298K
19.41 mtpa, 750 psia, 273K
7.47 mtpa, 14.7 psia, 241K
750 psia, 273K
HYDRATE SYNTHESIS CSTR For 1.5 mtpa methane
production: Vtotal=(3,130 mol
CH4/s)/(1.29 mol/m3 * s) Vtotal=2,430 m3
32 reactors usedVreactor = 76 m3
Perry, R., & Green, D. (1997). Perry's Chemical Engineers' Handbook (7th ed.). McGraw-Hill.
HYDRATE SYNTHESIS CSTR
Equipment Cost: $1,760,000
Perry, R., & Green, D. (1997). Perry's Chemical Engineers' Handbook (7th ed.). McGraw-Hill.
HYDRATE SYNTHESIS Compressor
s Compressors sized using
PRO II
Compressor Equipment Cost:
Recycle Compressor Cost: $2,200,000
Intake Compressor Cost: $870,000
Total Cost: $3,070,000
Perry, R., & Green, D. (1997). Perry's Chemical Engineers' Handbook (7th ed.). McGraw-Hill.
HYDRATE SYNTHESIS Pumps Pumps sized using
P = HQη/3960
H = 150ft n = 74% Q = 3,800 lb/s
Pump cost:
$690,000
Perry, R., & Green, D. (1997). Perry's Chemical Engineers' Handbook (7th ed.). McGraw-Hill.
HYDRATE SYNTHESIS Heat
Exchangers
Heat exchangers sized using: Q=UA∆T
Heat exchanger cost based on area
Initial Cooling Heat Exchanger Area: 35,000 ft2
Initial Cooling Heat Exchanger Cost: $235,000
Post Cooling Heat Exchanger Area: 16,000 ft2
Post Cooling Heat Exchanger Cost: $113,000Perry, R., & Green, D. (1997). Perry's Chemical Engineers' Handbook (7th ed.). McGraw-Hill.
HYDRATE TRANSPORTATION
Capacity 145,000 metric tons Capacity of 186,000 m3
Length 290m Beam 45m Draught 18m Base price $165,000,000
UNCTAD, S. (2007). Review of Maritime Transport. New York and Geneva: United Nations.
HYDRATE TRANSPORTATION - SLURRY
Slurry Transport Advantages
• Faster loading and unloading (8400 – 14000 tons per hour).
• Ease of handling hydrate as fluid.
Slurry Transport Disadvantages• Loss of ship capacity to anti-
freezing agents (4% - 5% of cargo weight).
• Additional equipment required to remove anti-freezing agents from gas.
HYDRATE TRANSPORTATION - SOLID
Solid Transport Advantages
• Simplified regasification facility.• Slightly more capacity per ship
than with slurry (4% - 5%).
Solid Transport Disadvantages• Slower loading and unloading
(2000 – 4000 tons per hour).• Additional solid handling
equipment required.
HYDRATE TRANSPORTATION
Distance
Transit Time (18kts)
Total Trip Time (Slurry/Solid)
Total Time Savings With Slurry
1000 mi 4.6 days 7.8 days/9.1 days
14.3%
2000 mi 9.3 days 12.5 days/13.8 days
9.4%
3000 mi 13.9 days 17.1 days/18.4 days
7.1%
4000 mi 18.5 days 21.7 days/23 days
5.7%
5000 mi 23.1 days 26.3 days/27.6 days
4.7%Slurry handling is the best option for shipping distances of 2500 miles or less.
Solid handling is the best option for shipping distances of 3500 miles or more.
HYDRATE TRANSPORTATION
Hydrate is stored in ship at equilibrium with either temperature or pressure.
The two limiting conditions are 1 atm of pressure at 241 K or 85 atm of pressure at 285 K.
Determinants of optimum pressure and temperature are cost and weight of steel required in hydrate storage vessel.
HYDRATE TRANSPORTATION
Faupel formula used to determine minimum steel thickness necessary for hydrate storage vessel.
Minimum Bursting Pressure =(2/√3)*Yield Tensile Strength*ln(Ratio of Inner and Outer Diameters)
1020 carbon steel used. Yield tensile strength of 1020 carbon steel is
350 Mpa.
HYDRATE TRANSPORTATION
Ambient Temperature Tank Outer Diameter29.5 mTank Thickness0.31mSteel Weight (if full length of vessel)113000 tons
0.31m
29.5m
HYDRATE TRANSPORTATION
Atmospheric PressureTank Outer Diameter29.5 mTank Thickness3.65mmSteel Weight (if full length of vessel)1300 tons
3.65mm
29.5m
HYDRATE TRANSPORTATION
Shipping cost for 1.5 mtpa and distance of 4000 miles.
Shipping at ambient temperature (FCI): $2,050,000,000
Shipping at atmospheric pressure (FCI): $1,100,000,000
HYDRATE TRANSPORTATION
Ballast
Ballast
Inner Hull
Insulation
Inner Membrane
Outer Membrane
HYDRATE TRANSPORTATION
358540 ton ice-hydrate blocks required
HYDRATE TRANSPORTATION
Refrigeration can be used to prevent hydrate dissociation.
With 4” of polyurethane insulation and a well-sealed cargo hold, 1.5 tons of refrigeration are required.
Cost of refrigeration $6,300
HYDRATE DISSOCIATION
PC
FC
Low PressureSteam
Condensate
SolidIce-Hydrate
Natural Gas toWater Removal
PressureVessel
Heating KettleLiquid Water
HYDRATE DISSOCIATION
Pressure Vessel size based on required production level of natural gas.
For 1.5 mtpa capacity.
44 pressure vessels: V = 294 m3
$5,400,000
776 storage vessels: V = 150 m3
$30,000,000
Perry, R., & Green, D. (1997). Perry's Chemical Engineers' Handbook (7th ed.). McGraw-Hill.
HYDRATE DISSOCIATION
Heating Costs for the kettle
Found using the heat of dissociation of methane hydrates, the specific heats of hydrate and water, and the required gas flow rate.
Cost of 1 MM BTU assumed to be $7.33
Total heating cost $40,000,000
Rueff, R. M., Sloan, E. D., & Yesavage, V. F. (1988). Heat Capacity and Heat of Dissociation of Methane Hydrates. AIChE Journal , 1468-1476.
PRODUCTION SUMMARY
The natural gas hydrates are produced in a stirred tank reactor.
The hydrates are frozen into blocks and loaded onto ships.
The ships have small refrigeration units to keep the blocks frozen.
The ships are at atmospheric pressure
PRODUCTION SUMMARY
The blocks of hydrates are decomposed in a pressurized vessel.
The hydrate leaves the vessel at pipeline pressure.
LNG COST ESTIMATION
Cost data for LNG was obtained at plant capacities of 1 mtpa, 2 mtpa, and 3.5 mtpa.
LNG COST ESTIMATION
Costs are taken as the average costs for a range of plant designs.
LNG COST ESTIMATION
Operating CostCapacity Liquification (2007$/ton) Regasification (2007$/ton)1000000 71.25 11.8752000000 61.75 7.1253500000 52.25 4.75
LNG COST ESTIMATION
Shipping costs are contracted out at $65,000/day for 57,000 tons LNG.
The total annualized cost for a LNG tanker is less than $23,000,000/year, or $63,000/day.
Contracting out the shipping is the worse case scenario for LNG.
UNCTAD, S. (2007). Review of Maritime Transport. New York and Geneva: United Nations.
ECONOMIC COMPARISON
The TAC per ton of methane produced is plotted against capacity in tons.
ECONOMIC COMPARISON
0 miles shows the TAC per ton that comes from the production and regasification plants.
Production
Regasification
ECONOMIC COMPARISON
Distance from Algeria to Cove Point, Maryland is about 4000 miles.
TAC per ton is shown for 1000 – 5000 miles.
50
100
150
200
250
300
0 200000 400000 600000 800000 1000000 1200000 1400000 1600000 1800000 2000000
$/to
n
Capacity (tons)
NGH TAC vs Capacity
0 miles
1000 miles
2000 miles
3000 miles
4000 miles
5000 miles
Increasing distance increases the TAC/ton. Adding ships causes a sharp increase in TAC/ton.
0
20
40
60
80
100
120
140
160
180
0 500000 1000000 1500000 2000000 2500000 3000000 3500000 4000000
($/t
on)
Capacity (tons)
LNG TAC per ton
0 miles
1000 miles
2000 miles
3000 miles
4000 miles
5000 miles
6000 miles
7000 miles
8000 miles
9000 miles
10000 miles
Increasing distance increases TAC/ton.
0
20
40
60
80
100
120
140
160
180
200
0 500000 1000000 1500000 2000000 2500000 3000000 3500000
$/to
n
Capacity (tons)
NGH and LNG TAC vs Capacity
NGH 0 miles
NGH 1000 miles
NGH 2000 miles
NGH 3000 miles
LNG 0 miles
LNG 1000 miles
LNG 2000 miles
LNG 3000 miles
LNG has a lower TAC/ton for transportation distances greater than 0 miles.
0
50
100
150
200
250
300
0 500000 1000000 1500000 2000000 2500000 3000000 3500000
$/to
n
Capacity (tons)
NGH and LNG TAC vs Capacity
NGH 4000 miles
NGH 5000 miles
NGH 6000 miles
NGH 7000 miles
LNG 4000 miles
LNG 5000 miles
LNG 6000 miles
LNG 7000 miles
Increasing transportation distance increases the difference in the TAC/ton for LNG and NGH.
ECONOMIC COMPARISON
The cost of shipping LNG is less than the shipping cost for NGH.
LNG has a higher energy density than NGH. 1 ton LNG = 1 ton natural gas 1 ton hydrate = 0.134 tons natural gas and
0.866 tons water. NGH requires 7 times the shipping weight of
LNG.
ECONOMIC COMPARISON
64%
7%
30%
Natural Gas Hydrates Cost
Breakdown
ShippingSynthesisRegasification
21%
68%
11%
LNG Cost Breakdown
ShippingSynthesisRegasification
For 1.5 mtpa transported 4000
miles
ECONOMIC COMPARISON
The FCI per ton of natural gas is plotted against the capacity in tons.
0 miles shows the FCI for the production and regasification plants.
0
200
400
600
800
1000
1200
1400
0 200000 400000 600000 800000 1000000 1200000 1400000 1600000 1800000 2000000
$/to
n
Capacity (tons)
NGH FCI vs Capacity
0 miles
1000 miles
2000 miles
3000 miles
4000 miles
5000 miles
FCI/ton increases with transportation distance.Adding ships produces a large increase in FCI/ton.
0
50
100
150
200
250
300
350
400
0 500000 1000000 1500000 2000000 2500000 3000000 3500000
($/t
on)
Capacity (tons)
NGH and LNG FCI per ton
NGH 0 miles
LNG 0 miles
The FCI/ton is cheaper for NGH.
ECONOMIC COMPARISON
The ROI is found by dividing the profit by the TCI.
The TCI is found by assuming thatTCI=FCI+WC=FCI/0.85
The profit is taken as sales-cost-depreciation, or sales-TAC.
Sales is varied between $0 and $200 per ton of methane
ECONOMIC COMPARISON
ROI is found by: ROI=((Sales-TAC)/TCI)*(ton/ton) ROI=(Sales/ton-TAC/ton)/(TCI/ton) ROI=((Sales/ton)/(TCI/ton))-((TAC/ton)/(TCI/ton))
(TCI/ton) and (TAC/ton) have already been calculated, therefore (Sales/ton) is only thing to vary.
A positive ROI occurs with sales of $80/ton.
-60
-40
-20
0
20
40
60
80
100
0 500000 1000000 1500000 2000000 2500000 3000000 3500000 4000000
ROI (
%)
Capacity (tons)
LNG 0 miles
0
20
40
60
80
100
120
140
160
180
200
A positive ROI occurs with sales of $100/ton for low production capacities.
-25
-20
-15
-10
-5
0
5
10
15
0 2000000 4000000 6000000 8000000 10000000 12000000
ROI (
%)
Capacity (tons)
NGH ROI 3000 miles
0
20
40
60
80
100
120
140
160
180
200
A positive ROI occurs with sales of $160/ton.
-60
-40
-20
0
20
40
60
80
0 500000 1000000 1500000 2000000 2500000 3000000 3500000 4000000
ROI (
%)
Capacity (tons)
LNG 3000 miles
0
20
40
60
80
100
120
140
160
180
200
A positive ROI occurs with sales of $120/ton.
-25
-20
-15
-10
-5
0
5
10
0 2000000 4000000 6000000 8000000 10000000 12000000
ROI (
%)
Capacity (tons)
NGH ROI 4000 miles
0
20
40
60
80
100
120
140
160
180
200
As distance increases the sales increases to $180/ton to maintain a positive ROI.
-60
-40
-20
0
20
40
60
80
0 500000 1000000 1500000 2000000 2500000 3000000 3500000 4000000
ROI (
%)
Capacity (tons)
LNG 4000 miles
0
20
40
60
80
100
120
140
160
180
200
As distance increases the sales increases to slightly above $120/ton to maintain a positive ROI.
0
50
100
150
200
250
300
350
400
0 500000 1000000 1500000 2000000 2500000 3000000 3500000
($/t
on)
Capacity (tons)
NGH vs LNG Peak-Shaving
NGH FCI/ton
LNG FCI/ton
NGH TAC/ton
LNG TAC/ton
Natural gas hydrate peak-shaving has a lower TAC/ton and FCI/ton than LNG.
-10
-5
0
5
10
15
20
25
0 1000000 2000000 3000000
%
Capacity (tons)
NGH vs LNG Peak-Shaving
NGH ROI ($100/ton)
LNG ROI ($100/ton)
Natural gas hydrate peak-shaving has a higher ROI than LNG.
CONCLUSION LNG has a lower TAC and a higher ROI.
LNG is a proven and well developed technology.
LNG is a better option than NGH for the transport of natural gas.
The TAC/ton, FCI/ton, and ROI is better for NGH with transportation distances of 0 miles.
NGH is a better option for peak-shaving the cost of natural gas.
QUESTIONS
