techno-economic modeling and engineering considerations of co2 pipelines
TRANSCRIPT
Techno-economic Modelling and Engineering Considerations of CO2 Pipelines !
Nima Ghazi
Cimarron Engineering Ltd.
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Topics to Discuss • CCS and CO2 Pipelines
• History of CO2 Pipelines
• Techno-economic Modelling of CCS Systems
• Calculation of a Pipeline Diameter
• Capital Cost Modelling of CO2 Pipelines (Pre-FEED)
• A Techno-economic Case Study
• Phase Envelope and Impact of Impurities
• Impact of Temperature and Pressure on Density
• Fracture Control of CO2 Pipelines
• Main Line Block Valve (MLBV) Assemblies
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Carbon Capture, ? , and Storage (CC?S) " The captured CO2 stream has to be transported from
the source to the sink.
" Onshore options: tank trucks (with trailers), railways, and pipelines
" Offshore options: ships and pipelines
" Large volumes onshore: pipelines
" For better project economics, CO2 has to be pressurized and cooled prior to pipeline transportation ( i.e. dense phase or super-critical state)
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Advantages of Techno-economic Analysis and Modelling of a CCS or CO2 -EOR Project
• Assess the technical and economic viability of the project
• Serves as a decision-making tool for the private and public sector (i.e. to go or not to go).
• Provides reliable results provided that the technical assessment of the project is well intertwined with its economic assessment.
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More on Techno-economic Analysis and Models
• A techno-economic model can be a useful tool if the applicability and validity of the assumptions are verified.
• Over-simplification should be avoided, e.g. $500,000 / km
• The number of fixed-value assumptions for critical variables should be minimized, e.g. fixed temperature or compressibility.
• The user of the model should understand the assumptions and principles behind the development of the model being used.
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Techno-economic Modelling and Analysis – Notes of Caution
• Over-simplification or making wrong assumptions can lead into making poor recommendations for major industrial projects.
• Poor recommendations can result in major economic (and social) losses.
• It is time consuming to synchronize the techno-economic variables across the full chain of CCS activities.
Results of Different Techno-economic Models for CO2 Pipeline Transport
Source: Ghazi and Race (2012)
Analysis of Different Techno-economic Models
Source: Ghazi and Race (2012)
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Pressure and Temperature Regions for Transporting CO2 via Different Methods
Source: Race (2009)
Temperature (°C)
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CO2 Transport Costs: Pipelines vs. Ships
Source: Ghazi and Kumar (2010)
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Existing or Planned CO2 Pipelines in the USA
Source: Steve Melzer, Melzer Consulting (2010)
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Examples of Existing CO2 Pipelines
" Canyon Reef Carriers (CRC) Pipeline: Built in 1972, 354 km, NPS 16, from McCamey, TX to SACROC oil field in Texas (Owned by KM)
" Largest CO2 Pipeline: Built in 1986, 808km, NPS 30, Cortez Colorado to Denver City Texas, 20 Mt / year (KM)
" Weyburn Pipeline: Built in 2000, 330 km, NPS 12, Coal Gasification Plant in North Dakota to Weyburn Oil Field in SK, Canada (Cenovus)
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Transmission Pipelines (USA)
• About 4,000 Miles of CO2 Pipelines
• 278,000 Miles of Natural Gas Transmission Pipelines
• 55,000 Miles of Crude Oil Trunk Lines
• 95,000 Miles of refined petroleum products: gasoline, jet fuel, home heating oil and diesel fuel
Source: http://www.pipeline101.com/overview/energy-pl.html
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Some of the CO2 Pipeline Parameters
" The locations of source and sink identify the start and finish (delivery) points of the pipeline.
" The pipeline route has to be optimized (economic, environmental, social and political considerations)
" Diameter and Wall-Thickness
" Maximum Operating Pressure and Temperature
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Calculation of a Pipeline’s Diameter
R↓e = U. D↓i /µμ⁄ρ
Reynolds Number
Darcy Friction factor
Darcy-Weisbach Pressure
Drop
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Pipeline Capital Cost Calculations
• Unlike calculation of pipeline’s diameter a capital cost model cannot be universally applied.
• Various location-specific cost elements
• Cost implications of different governing regulations that impact the final cost of a specific CCS or CO2 pipeline project
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Capital Cost Modelling • Limited cost data available for construction of CO2 pipelines.
• The available capital cost data for natural gas pipelines can be used as the cost of construction is largely independent of the transported fluid. [can lead into under-estimation of cost]
• The cost data should be normalized to one reference year, preferably to the current year.
• Cost normalisation: the project’s value for return-on-equity (ROE) rate, return-on-debt (ROD) rate, and each corresponding year’s inflation rate have to be accounted for.
• Through regression analysis it is possible to derive an equation that provides a best-fit to the available cost data, (highest adjusted-r2 value).
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Results of Regression Analysis* • Total Pipeline Capital Cost = Pipeline Capital Cost onshore + Pipeline Capital Cost
offshore
• Pipeline Capital Cost onshore (€) =
• FL * FT *106 *[(0.057*Lonshore+1.8663) + (0.00129*Lonshore)*Do + (0.000486*Lonshore - 0.000007)*Do
2]
•
• Pipeline Capital Cost offshore (€) =
• FL * 106 * [(0.4048*Loffshore + 4.6946) - 0.00153*Loffshore + 0.0113)* Do + (0.000511* Loffshore + 0.00024)* Do
2]
*Year 2005 Values
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The Yorkshire and Humber CCS Cluster
Courtesy of CO2Sense Yorkshire, (2010)
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Yorkshire-Humber Region’s Techno-economic Figures
Variable Value
Design Life (yrs) 40
SMYS (MPa) 413 (X60)
P-inlet (Mpa) 12.5
P-outlet (Mpa) 10.0
m (kg/s) 1616.7
T-max (°C) 30
T -ave (°C) 20
L-onshore (km) 109
L-offshore (km) 135
L-total (km) 244
Density (kg/m3) 800
Viscosity (Pa.s) µ=6.06*10-5
D.F. 0.72
Plant C.F. 0.85
Pipe Variable Value
Pipe O.D. (Inch) 48
Wall Thickness (mm) 25.57
Cost Item Cost (Million)
Total Capital (Million £) 61
O&M (Mill £) 2
Normalized Cost (£/tonne) 1.22
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Engineering Design of a CO2 -EOR or CCS System
" It should be a well-coordinated effort between those involved in designing the capture, compression, transport, injection, EOR and sequestration aspects of the overall system.
" Unwanted challenges if each part is designed in isolation.
" For example: 1) the required delivery pressure and temperature downstream dictate the compression and cooling requirements upstream and 2) the required chemistry of the stream to be injected can impact the choice of capture technology upstream.
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Phase Envelope of Pure CO2
Source: Ghazi and Race (2012)
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Impact of Impurities on the Phase Envelope
Phase Envelope Changes with Increasing Impurity (Yorkshire Forward, 2009)
Pressure (bar)
Temperature (°C)
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Impact of Pressure and Temperature on Density
Density of Pure CO2 at Various Temperatures and Pressures. Courtesy of Kinder Morgan (2002)
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Project Pioneer (CO2 EOR and CCS)
Courtesy of Enbridge and Cimarron Engineering Ltd. (2012)
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A few questions on CO2 Pipelines’ Safety Design Considerations
• Is CO2 corrosive?
• Which one favors a safer design: a higher or lower operating pressure in the dense phase?
• Which impurities are worst?
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Arrest of Long Running Brittle and Ductile Fractures! " The pipeline shall have adequate toughness against
fracture propagation.
" Brittle fractures are controlled by designing so the material would be on the upper-shelf of its energy-temperature curve during the pipeline operation.
" Lowering operating temperature or removing impurities that have a lower critical temperature than of CO2’s will assist with fracture control
" How about the impact of pressure on fracture?
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Pressure-Enthalpy for CO2
Text Text
Source: Mohitpour et. al (2012)
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Enthalpy Diagram for 95% CO2 and 5% N2 [Molar]
Source: Report Prepared for Cimarron Engineering Ltd. (2012)
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Decompression from 17 MPa
Source: Graeme King, Tensor Engineering Ltd. (2010)
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Decompression from 21 MPa
Source: Graeme King, Tensor Engineering Ltd. (2010)
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Decompression from 25 MPa
Source: Graeme King, Tensor Engineering Ltd. (2010)
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Design Optimization • The optimum MOP for all pipe sizes is close to 25 MPa
• Higher pressures are not expected to further reduce cost
• At 25 MPa the wall is already thick enough from the Barlow equation that easily achievable toughness can prevent fractures
• 25 MPa is close to pressure rating of 1500 Class flanges and the cost of 2500 Class flanges puts a step in the optimization curves
• More economic to use wall thickness and toughness to prevent ductile fractures rather than fracture arrestors to limit the length of fractures
• But main benefit of higher MOP is safety—pipeline will leak rather than burst giving the operator time to locate and repair it without catastrophic failure
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• MLBVs are typically full-bore ball valves: they respond more easily than gate valves under high differential pressures
• Valve assemblies include two blow-down stacks and a by-pass between them to help with loading and pressuring sections of the line.
• Dispersion model studies should be done to help plan the MLBV locations, blow down time and an ERP.
MLBV and Blow-down Configuration
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" Use of elastomers in the seats is not recommended (Teflon Preferred)
" Valve assemblies should be shop fabricated, pre-tested and coated before field installation (hydro-test to 1.5x design pressure)
" Typical blow-down time for a section of the line could be up to 3 hours.
MLBV and Blow-down Configuration
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MLBV and Blow-down Configuration
To ensure that the full pressure and temperature drop occurs across the assembly outlet to the atmosphere, rather than across the blow down valve, the end-closures or flanges on the blow-down outlet should be smaller than the bore of the blow down valves.
Source: Cimarron (2012)
