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Efficient Compression of CO2 and Pipeline Transport Considerations_1_

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Efficient Compression of CO2 and Pipeline Transport Considerations_1_ Powered By Docstoc
					Novel Concepts for the Compression
         and Transport of
      Large Volumes of CO2
                                     J. Jeffrey Moore, Ph.D.
                                  Southwest Research Institute

                                                                  Compression Technology Options for IGCC Waste
                                                                             Carbon Dioxide Streams

                                                          10000
                                                                      Liquid Cryo-Pump                               High Ratio
                                                                                                                   Shock Compress.
                                                                      "Option E"
                                                                                                                      Compression
                                                                                                                   "Option D"


                                                           1000
                                        Pressure (psia)




                                                                                                                      Conventional
                                                                              Semi-
                                                                                                                     "Option A"
                                                            100               Isothermal
                                                                              "Option C.3"
                                                                                                                   Conventional
                                                                               Isothermal                          "Option B"
                                                                               "Option C.1"

                                                             10
                                                                  0      50      100     150        200      250   300    350        400
                                                                                             Enthalpy (Btu/lbm)




RPSEA CO2 Operations and Opportunities to Advance Technology for Mature Fields Forum                                                       Southwest Research Institute
         Who Is SOUTHWEST RESEARCH INSTITUTE?



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RPSEA CO2 Operations and Opportunities to Advance Technology for Mature Fields Forum   Southwest Research Institute
                              Project Motivation
• CO2 capture of coal fired power plants has a
  significant compression penalty
    – As high as 8 to 12%.
• Final pressure around 1,500 to 2,200 psia for
  pipeline transport or re-injection (EOR, ground
  storage, etc.).
• Based on a 400 MW IGCC plant, the typical flow
  rate is ~600,000 to 700,000 lbm/hr.
• Project goal: Double-digit reduction of
  compression power for CO2 capture
• Many thermodynamic processes studied.
• Currently in demonstration phase as part of a
  $1.5 million DOE project
 RPSEA CO2 Operations and Opportunities to Advance Technology for Mature Fields Forum   Southwest Research Institute
                          General Comments
• The type of compressor is highly dependent on the
  starting pressure (15 or 300 psia).
    – Approximately 20 to 500 psia for CO2 scrubbing of the fuel
      stream (for IGCC).
    – Approximately 15 psia from CT or boiler exhaust scrubber.
• High pressure ratio results in significant heat of
  compression.
• Various compressor types have been considered.
• Isothermal compression - one concept considered to
  reduce the power of compression.
• Liquefaction of CO2 has also been studied.
RPSEA CO2 Operations and Opportunities to Advance Technology for Mature Fields Forum   Southwest Research Institute
        IGCC Process with Carbon Capture




RPSEA CO2 Operations and Opportunities to Advance Technology for Mature Fields Forum   Southwest Research Institute
              Required Inlet Volume Flow for C02
                         Compressor
           Mass Flow Rate = 700,000 lbm / hr = 144.89 MMSCFD


   Pressure             Volume Flow
    (psia)                 (acfm)
          14.7                100,595.2
         150                      9,858.3
         300                      4,929.2
         450                      3,286.1
         600                      2,464.6
      1,000                       1,478.8
      1,500                          985.8

                                                          High volume flow reduction adds to
                                                          challenge in compressor selection

RPSEA CO2 Operations and Opportunities to Advance Technology for Mature Fields Forum   Southwest Research Institute
                   Example IGCC CO2 Separator
                            Conditions
• Uncompressed CO2 streams in a typical IGCC plant with a
  physical absorption separation method using Selexol solvent.

         CO2 Gas Streams                             LP              MP            HP 1            HP 2
         Pressure (psia)                               21.9         160.0           250.0            299.0
         Temperature (°F)                              51.0           68.0               90.0           75.0
         Density (lbm/ft3)                           0.177               1.3             1.87        2.088
         Flow Rate (acfm)                         33,257            2,158           3,374            1,073


  Higher pressure separation streams help reduce volume reduction.
  This allows a more uniform frame size in compressor selection.

  RPSEA CO2 Operations and Opportunities to Advance Technology for Mature Fields Forum          Southwest Research Institute
               Comparison of Isentropic & Isothermal Paths




       Typical P-h diagram depicts
       the isothermal and isentropic
       path lines for CO2.




  Carbon Dioxide Pressure-Enthalpy Diagram – Provided by Gulf Publishing Company-1972, Fig.8.2
RPSEA CO2 Operations and Opportunities to Advance Technology for Mature Fields Forum   Southwest Research Institute
                           Path Dependent Process Comparison

                                               Required Compression Power:
                                         Path-Dependency of Compression Process
                           10000
                                       Isothermal Lines Shown
                                       (T=100-140degF)
                                                                         Isothermal Compression at
                                                                         100 degF, 60% efficiency
                           1000
         Pressure (psia)




                                                   Vapor-Liquid
                                                                                             Isentropic
                                                   Dome for CO2
                                                                                             Compression
                            100                                                              (100% efficiency)




                             10
                                   0      50      100     150      200     250       300    350       400        450
                                                                Enthalpy (Btu/lbm)

              Comparing a 60% isothermal compressor to a 100% efficient
                     isentropic compressor…Which is better???
RPSEA CO2 Operations and Opportunities to Advance Technology for Mature Fields Forum                 Southwest Research Institute
                              Isentropic vs. Isothermal Compression
Isentropic Compression Calculations for 20-2200 psia
                                                                                                      Mdot (lb/hr)=   200000
                                                                 rho1      rho2    Polytropic           W/mdot
   P1         P2         T1         T2       h1         h2    (lbm/ft3) (lbm/ft3) Efficiency           (Btu/lbm)      BHP
        20     220            70     415    216.05     290.92      0.156    1.0446        0.99             74.870      5879.6
                                                                                                      Mdot (lb/hr)=   200000
     220       2200       415        875    290.92     404.12          1.0446    6.6665          1.00     113.200      8889.6

                                                                                                      Total BHP =     14769.2
             Isothermal Compression Calculations at 100 degF and 60% efficiency
             Low Pressure                                                Mdot (lb/hr)=           200000

                                                        Ideal                       Actual
                                                 ln    W/mdot Assumed               W/mdot
               P1        P2        To   P2/P1 (P2/P1) (Btu/lbm) Efficiency         (Btu/lbm)     BHP
                    20    100       100   5.00    1.61    37.62      0.600             62.705     4924.2
                                                                                                           Isentropic Compression
             Side Stream + Medium Pressure                                       Mdot (lb/hr)=   200000
                                                                                                           (100% efficiency) = 14,769 BHP
                                                        Ideal                      Actual
                                                 ln    W/mdot Assumed              W/mdot
               P1        P2        To   P2/P1 (P2/P1) (Btu/lbm) Efficiency        (Btu/lbm)      BHP
                100       260       100   2.60    0.96    21.28      0.600             35.461     2784.8

                 170      260      100     1.53      0.42       9.32       0.600
                                                                                 Mdot (lb/hr)=
                                                                                       15.541
                                                                                                 200000
                                                                                                  1220.4
                                                                                                           Isothermal Compression
             High Pressure                                                       Mdot (lb/hr)=   200000
                                                                                                           (60% efficiency) = 12,441 BHP
                                                        Ideal                      Actual
                                                 ln    W/mdot Assumed              W/mdot
               P1        P2        To   P2/P1 (P2/P1) (Btu/lbm) Efficiency        (Btu/lbm)      BHP
                260       600        70   2.31    0.84    16.41      0.600             27.344     2147.3
                600      1097        70   1.83    0.60     6.50      0.600             10.841      851.4
                                                                                 Mdot (lb/hr)=   200000         The 60% efficient isothermal
               1097      2200        70    2.01      0.70       3.92       0.600        6.536      513.3
                                                                                                                 compressor is preferred.
                                                                                 Total BHP =     12441.4

        RPSEA CO2 Operations and Opportunities to Advance Technology for Mature Fields Forum                                    Southwest Research Institute
               Summary of Thermodynamic Analysis


                                        Compression Technology Options for IGCC Waste
                                                   Carbon Dioxide Streams

                                10000
                                            Liquid Cryo-Pump
                                                                                         Shock Compress.
                                                                                         High Ratio
                                            "Option E"
                                                                                         "Option D"
                                                                                         Compression

                                 1000
              Pressure (psia)




                                                                                             Conventional
                                                    Semi-
                                                                                            "Option A"
                                  100               Isothermal
                                                    "Option C.3"
                                                                                          Conventional
                                                     Isothermal                           "Option B"
                                                     "Option C.1"

                                   10
                                        0      50      100     150        200      250   300     350        400
                                                                   Enthalpy (Btu/lbm)


RPSEA CO2 Operations and Opportunities to Advance Technology for Mature Fields Forum                     Southwest Research Institute
                                 Semi-Isothermal Process
                                 Compression Technology Options for IGCC Waste Carbon
                                                    Dioxide Streams
                                      Isothermal vs. Semi-Isothermal Compression
                10000
                                                Semi-Isothermal
                                                "Option C.3"
    Pressure (psia)




                      1000




                      100

                                         Isothermal
                                         "Option C.1"


                       10
                             0     50     100       150      200         250           300      350          400
                                                    Enthalpy (Btu/lbm)
RPSEA CO2 Operations and Opportunities to Advance Technology for Mature Fields Forum         Southwest Research Institute
         Semi-Isothermal Process Compared
             to Isothermal Performance
                               Thermodynamic Comparison of Compression Process
                                       for Carbon Dioxide (22-2215 psia)

                                                               Isothermal ~ 80%
                            30000
                                                               Semi-isothermal at poly eff = 80%
                                                               Isothermal, ideal
                            27500                              Semi-isothermal, ideal
                                                               Conventional at poly eff ~ 80%
                            25000                              High Ratio Comp at poly eff ~ 80%

                            22500
                      BHP




                            20000

                            17500

                            15000

                            12500

                            10000
                                    0           5            10              15             20
                                    No. of Compression Steps / Inter-stage Cooling


               17 semi-isothermal inter-cooled stages approach the
                minimum horsepower of isothermal performance.
RPSEA CO2 Operations and Opportunities to Advance Technology for Mature Fields Forum               Southwest Research Institute
                                   Liquefaction Process Comparison

                                  Compression Technology Options for IGCC Waste Carbon
                                                    Dioxide Streams
                                                 Basic Options A, C, E
         10000
                               Liquid Cryo-Pump
                               "Option E"



                 1000
   Pressure (psia)




                                                                                        Conventional
                     100                                                               "Option A"




                     10
                           0       50       100   150      200         250         300        350          400
                                                   Enthalpy (Btu/lbm)
RPSEA CO2 Operations and Opportunities to Advance Technology for Mature Fields Forum         Southwest Research Institute
                    Summary of Thermodynamic Analysis



• Liquefaction process
      – Utilize a refrigeration system to condense CO2
        at about 250 psia and -20ºF.
      – Liquid then pumped from 250 to 2,215 psia.
      – Requires significantly less power to pump
        liquid than to compress a gas.
      – The cost of the refrigeration system must be
        accounted for.


RPSEA CO2 Operations and Opportunities to Advance Technology for Mature Fields Forum   Southwest Research Institute
                             Proposed Solution for Optimal Efficiency

                                     Compression Technology Options for IGCC Waste
                                                Carbon Dioxide Streams
                         10000




                          1000
       Pressure (psia)




                                                                                                Conventional
                                                                                               "Option A"
                                              Proposed Solution
                           100
                                              "Option E.2"




                            10
                                 0       50        100      150          200           250   300      350         400
                                                                  Enthalpy (Btu/lbm)

Optimal solution combines inter-stage cooling and a liquefaction approach.
RPSEA CO2 Operations and Opportunities to Advance Technology for Mature Fields Forum                Southwest Research Institute
           Summary of Thermodynamic Analysis

                                                            Power               % Diff from
Option         Compression Technology                    Requirements            Option A        Cooling Technology

         Conventional Dresser-Rand                                                            Air-cool streams between
  A                                                        23,251 BHP               0.0%
         Centrifugal 16-stage Compression                                                     separate stages

         Conventional Dresser-Rand                                                            Air-cool streams between
  B      Centrifugal 16-stage Compression                  21,522 BHP              -7.4%      separate stages using ASU
         with additional cooling                                                              cool N2 stream
         Isothermal compression at 70 degF                                                    Tc = 70 degF inlet temp
 C.1                                                       14,840 BHP              -36.2%
         and 80% efficiency                                                                   throughout
                                              17,025 BHP
         Semi-isothermal compression at 70                                                    Tc = 70degF in between
 C.4                                        (Required Cooling                      -26.8%
         degF, Pressure Ratio ~ 1.55                                                          each stage.
                                              Power TBD)
                                              17,979 BHP
         Semi-isothermal compression at 100                                                   Tc = 100degF in between
 C.7                                        (Required Cooling                      -22.7%
         degF, Pressure Ratio ~ 1.55                                                          each stage.
                                              Power TBD)




   RPSEA CO2 Operations and Opportunities to Advance Technology for Mature Fields Forum        Southwest Research Institute
                      Summary of Thermodynamic Analysis

                                                           Power              % Diff from
Option        Compression Technology                    Requirements           Option A       Cooling Technology
         High ratio compression at 90%
 D.3                                                      34,192 BHP            47.06%      Air cool at 2215 psia only
         efficiency - no inter-stage cooling


         High ratio compression at 90%
                                                                                            Air cool at 220 and 2215
 D.4     efficiency - intercooling on final               24,730 BHP             6.36%
                                                                                            psia
         compression stage


                                                          16,198 BHP
         Centrifugal compression to 250                                                     Air cool up to 250 psia,
                                                        (Includes 7,814
 E.1     psia, Liquid cryo-pump from 250-                                       -30.33%     Refrigeration to reduce
                                                            BHP for
         2215 psia                                                                          CO2 to -25degF to liquify
                                                        Refrigeration) 1
                                                                                            Air cool up to 250 psia
         Centrifugal compression to 250 psia              15,145 BHP
                                                                                            between centrifugal
         with semi-isothermal cooling at 100            (Includes 7,814
 E.2                                                                            -34.86%     stages, Refrigeration to
         degF, Liquid cryo-pump from 250-                   BHP for
                                                                                            reduce CO2 to -25degF to
         2215 psia                                      Refrigeration) 1
                                                                                            liquify

  RPSEA CO2 Operations and Opportunities to Advance Technology for Mature Fields Forum        Southwest Research Institute
                        Phase 2 Project Plan
• Experimentally validate thermodynamic
  predictions.
• Two test programs envisioned:
     – Liquid CO2 pumping loop
     – Closed-loop CO2 compressor test with internal
       cooling
• Power savings will be quantified in both
  tests.


RPSEA CO2 Operations and Opportunities to Advance Technology for Mature Fields Forum   Southwest Research Institute
                   Internally Cooled Compressor Testing

• Existing Multi-Stage Test Rig will be utilized using CO2




RPSEA CO2 Operations and Opportunities to Advance Technology for Mature Fields Forum   Southwest Research Institute
                  Liquid CO2 Loop


•     Vessel layout
      showing elevated
      reservoir and knock-
      out drum
•     Pump will be
      mounted at ground
      level.
•     Orifice run will be
      located between
      pump and control
      valve (in supercritical
      regime)



    RPSEA CO2 Operations and Opportunities to Advance Technology for Mature Fields Forum   Southwest Research Institute
                                  Program Benefits
•   Provide enabling technology to compress CO2 from a coal-fed IGCC power
    plant, cost-effectively minimizing the financial impact of CO2 sequestration.
•   Supports carbon capture to eliminate green-house gas emissions from
    power plants, which make up 35% of total CO2 emissions.
•   This program identified up to 35% power savings over a conventional CO2
    compression solution.
•   Similar savings identified for Pulverized Coal (PC) plant
•   The thermodynamic process is more important than compressor efficiency.
•   The internally-cooled compressor concept will add minimal cost.
•   Liquefaction and pumping equipment will add some additional capital
    expense, but some is offset by lower cost pump compared to high-
    pressure compressor.
     – A 35% power reduction will save a utility $4.2 million per year, based on 4¢ /
       kwh, which will provide a fast return on investment.
•   Phase 2 has recently been funded and is underway


    RPSEA CO2 Operations and Opportunities to Advance Technology for Mature Fields Forum   Southwest Research Institute
                      Expected Growth of CO2 Pipelines
• Population growth predictions
   – Based on the DOE EIA 2007 Annual Energy Outlook (AEO 2007) and a
     study conducted by Columbia University, the western and southeastern
     states are expected to have the most population growth to 2030.
   – The AEO 2007 also predicts the most new coal capacity in those areas.
• Pipeline predictions
   – Based on the predicted population growth, areas of existing coal mines,
     locations of natural gas pipelines, and potential CO2 sequestration
     locations, sites were chosen for future coal-fired power plants.
       • CO2 pipelines were then placed from each site to possible EOR sites,
         deep-saline aquifers, or major flood basalt formations.
       • The total pipeline length for the potential power plant sites was
         linearly interpolated for the number of Integrated Gasification
         Combined Cycle (IGCC) and Pulverized Coal (PC) plants requiring
         carbon capture and sequestration (CCS) by 2030.

   RPSEA CO2 Operations and Opportunities to Advance Technology for Mature Fields Forum   Southwest Research Institute
            Expected CO2 Pipelines for EOR
       For pipelines longer than 200 miles, any new CO2 pipeline
       was assumed to follow existing NG pipeline right-of-way.




RPSEA CO2 Operations and Opportunities to Advance Technology for Mature Fields Forum   Southwest Research Institute
                    Expected CO2 Pipelines for
                     Geological Sequestration
       Due to the prevalence of saline aquifers identified for potential
      carbon storage, pipelines for geological storage locations tend to
          be considerably shorter than pipelines for EOR service.




RPSEA CO2 Operations and Opportunities to Advance Technology for Mature Fields Forum   Southwest Research Institute
                  Future Research Needs

• Tremendous opportunity to reduce compression
  costs
• Pipeline transmission compression needs to be
  evaluated
• Recovering energy when EOR injection is less
  than Pipeline pressure
• Gas metering research of supercritical fluid
  needed
• Studies for the optimum placement of future
  pipelines between sources and sinks needed

RPSEA CO2 Operations and Opportunities to Advance Technology for Mature Fields Forum   Southwest Research Institute
                           Questions???
                                  www.swri.org
                               Dr. J. Jeffrey Moore
                           Southwest Research Institute
                                 (210) 522-5812
                              Jeff.Moore@swri.org



RPSEA CO2 Operations and Opportunities to Advance Technology for Mature Fields Forum   Southwest Research Institute

				
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