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Integration of Oxygen Transport Membranes in an IGCC power plant with CO2 capture
 

Integration of Oxygen Transport Membranes in an IGCC power plant with CO2 capture

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    Integration of Oxygen Transport Membranes in an IGCC power plant with CO2 capture Integration of Oxygen Transport Membranes in an IGCC power plant with CO2 capture Presentation Transcript

    • Integration of Oxygen TransportMembranes in an IGCC power plant withCO2 captureRahul Anantharaman1 and Olav Bolland21 SINTEF Energy Research, Energy Processes2 Department of Energy and Process Engineering, NTNUPRES 2011, FlorenceMay 9, 2011 s s s s s s SINTEF Energy Research s s s s s s 1
    • Overview of PresentationIntroduction Motivation Oxygen Transport Membranes Objective Project FrameworkIntegration of oxygen membranes in an IGCC Membrane operating methods Air integrationSummary s s s s s s SINTEF Energy Research s s s s s s 2
    • concluded that the performance penalty associated with using E-class gas t technology would be a barrier to successful deployment of pre-combustion capture.Integrated Gasification Combined Cycle These processing steps are shown in the outline flow scheme in Figure 3.1:(IGCC) DYNAMIS D5.3.2:IGCC with pre-combustion CO2 Figure 3.1: Recommendations for HYPOGEN Initiative capture for co-production of electricity and hyd s s s s s s from coal and lignite. SINTEF Energy Research s s s s s s 3
    • Air Separation Unit I ASU supplies O2 at 95% purity. I Theoretical minimum work consumption: 49 kWh/ton of O2 produced. I State-of-the-art cryogenic ASU consumes: 175-200 kWh/ton of O2 produced. I Cryogenic ASU development prospects: 145-160 kWh/ton of O2 produced. s s s s s s SINTEF Energy Research s s s s s s 4
    • Oxygen Transport Membranes I Dense ceramic membranes (metal oxides). I Membrane operation based on mixed conduction of ions and electrons. I Separates O2 from air with 100% selectivity. I Operating temperature range: 800-1000°C. s s s s s s SINTEF Energy Research s s s s s s 5
    • Integration of OTM in an IGCC I OTM are a promising technology that present a major source of efficiency improvement I Challenge lies in efficient integration of such membrane in an IGCC to realize this potentialObjectives I Develop efficient cycles integrating an Oxygen Transport Membranes as an ASU in an IGCC plant to reduce efficiency penalty. I Insight into considerations for such an integration. s s s s s s SINTEF Energy Research s s s s s s 6
    • Framework I This work was done as part of the EU FP7 project DECARBit. I DECARBit investigates several advanced pre-combustion capture technologies, both at a fundamental and more applied level. SP1 System integration and optimisation including application to other industries SP2 Advanced Pre- combustion CO2 separation CO2 to Coal storage Gasifier, Shift CO2 CO2 Reformer reactors H2, separation compression Natural CO2 gas O2 SP4 Enabling H2 technologies for (fuel pre-combustion gas) Air Electric Air Separation N2 Gas Steam power Unit turbine Cycle SP3 Advanced oxygen separation technologies SP5 Pre-combustion pilots s s s s s s SINTEF Energy Research s s s s s s 7
    • Reference cases I European Benchmarking Task Force (EBTF) established between 3 EU FP7 projects - CESAR, CAESAR and DECARBit. I EBTF developed and published document on benchmarking reference cases with and without capture for 1. Advanced Supercritical Pulverized Coal (post-combustion). 2. Integrated Gasification Combined Cycle (pre-combustion). 3. Natural Gas Combined Cycle (post-combustion). I Reference case for IGCC without capture: 46.88 %. I Reference case for IGCC with 90% CO2 capture: 36.66 %. I Relevant assumption: 50% air integration between GT and ASU. s s s s s s SINTEF Energy Research s s s s s s 8
    • Membrane system design I The driving force is the partial pressure difference (pO2 = xO2 · P ) between the oxygen rich feed side and the permeate side. I The oxygen flux across the membrane is given by modified RT ln pO ,perm σel σion Wagner’s equation: JO2 = − 16F 2 L 2 ln pO ,feed σel +σion ∂ ln pO2 2 I Give a feed side oxygen partial pressure, to increase flux 1. xO2 ,perm should decrease, and/or 2. Pperm should should decrease. s s s s s s SINTEF Energy Research s s s s s s 9
    • Membrane system design I The driving force is the partial pressure difference (pO2 = xO2 · P ) between the oxygen rich feed side and the permeate side. I The oxygen flux across the membrane is given by modified RT ln pO ,perm σel σion Wagner’s equation: JO2 = − 16F 2 L 2 ln pO ,feed σel +σion ∂ ln pO2 2 I Give a feed side oxygen partial pressure, to increase flux 1. xO2 ,perm should decrease, and/or 2. Pperm should should decrease. s s s s s s SINTEF Energy Research s s s s s s 9
    • Membrane system design I The driving force is the partial pressure difference (pO2 = xO2 · P ) between the oxygen rich feed side and the permeate side. I The oxygen flux across the membrane is given by modified RT ln pO ,perm σel σion Wagner’s equation: JO2 = − 16F 2 L 2 ln pO ,feed σel +σion ∂ ln pO2 2 I Give a feed side oxygen partial pressure, to increase flux 1. xO2 ,perm should decrease, and/or 2. Pperm should should decrease. s s s s s s SINTEF Energy Research s s s s s s 9
    • Membrane system design I The driving force is the partial pressure difference (pO2 = xO2 · P ) between the oxygen rich feed side and the permeate side. I The oxygen flux across the membrane is given by modified RT ln pO ,perm σel σion Wagner’s equation: JO2 = − 16F 2 L 2 ln pO ,feed σel +σion ∂ ln pO2 2 I Give a feed side oxygen partial pressure, to increase flux 1. xO2 ,perm should decrease, and/or 2. Pperm should should decrease. s s s s s s SINTEF Energy Research s s s s s s 9
    • Membrane operating methodwith sweep gas I Advantages: – Improved mechanical stability. – O2 is produced at higher pressure and hence compression work to gasifier condition is reduced. I Disadvantages: – Sweep gas temperature should be close to that of the feed side. – Sweep gas requirement. s s s s s s SINTEF Energy Research s s s s s s 10
    • Sweep gas I Sweep gas will dilute the O2 . I Sweep gas can either be Steam or CO2 . I Large flow of sweep gas are required. I Steam – Extracted from bottoming cycle. – Leads to large efficiency penalty. I CO2 – Recycled after separation from syn-gas and requires compression. – CO2 sweep increases CO2 captured, thus increasing energy penalty. – This is partly offset by the increased partial pressure of CO2 in the acid gas removal section. s s s s s s SINTEF Energy Research s s s s s s 11
    • Sweep gas - efficiency penalty 120 37 Steam flow (kg/s) 110 Energy penalty (MW) 32 nergy Penalty (MW) 100 Steam flow (kg/s) 90 27 80 22 70 En 17 60 50 12 10 12 14 16 Sweep gas pressure (bar) s s s s s s SINTEF Energy Research s s s s s s 12
    • Membrane operating methodwithout sweep gas I Advantages: – No efficiency penalty associated with sweep gas. I Disadvantages: – O2 produced at lower pressure leading to increased compression penalty. – Mechanical stability of membrane system. s s s s s s SINTEF Energy Research s s s s s s 13
    • 50% air integration - Scheme 1 s s s s s s SINTEF Energy Research s s s s s s 14
    • 50% air integration - Scheme 1 I Efficiency lower than reference case with cryogenic ASUReasons for low efficiency I Raising the OTM feed temperature to 900°C results in losses from the extra fuel conversion to H2 and eventual combustion in this process. I Transport limitation: The overall plant efficiency depends on the degree of O2 separation - mO2 ,perm /mO2 ,feed . The degree of separation for the process under consideration is 0.45. I A separate ASU required for N2 production. Nitrogen required for gas turbine fuel dilution and coal transport is supplied by a cryogenic ASU. I Improper integration! s s s s s s SINTEF Energy Research s s s s s s 15
    • Reference case - Temperature profile s s s s s s SINTEF Energy Research s s s s s s 16
    • 50% Integration - Scheme 2 s s s s s s SINTEF Energy Research s s s s s s 17
    • 50% air integration - Scheme 2 I Efficiency lower than reference case with cryogenic ASUReasons for low efficiency I Turbine Inlet Temperature (TIT) is reduced compared to the reference case leading to increased efficiency penalty. I Transport limitation. I Need for seprate ASU for N2 production. I Improper integration! s s s s s s SINTEF Energy Research s s s s s s 18
    • 100% Integration s s s s s s SINTEF Energy Research s s s s s s 19
    • Figure 3: Process block diagram for OTM integrated IGCC plant with CO2 capture100% Integration - Performance Table 1: Overall plant performance of OTM integrated IGCC plant with CO2 capture Coal flow rate 138.9 Tph Thermal energy of fuel (LHV) 969.7 MWth Thermal energy for coal drying 8.23 MWth Gas turbine output 280.5 MWe Steam turbine output 176.6 MWe Gross electric power output 457.1 MWe Total ancillary power consumption 92.1 MWe Net electric power output 365.0 MWe Net electric efficiency 37.3 % CO2 capture rate 90.9 % 5. Conclusions System considerations for integration of an oxygen transport membrane based air separation unit are presented. Arguments for selection of membrane operating mode and I Heat and mass GT is selected. detail. An integrated IGCC shows anand 100% airwith heating air integration are discussed in integration with integration removewithout sweep gas efficiency gain of The OTM OTM losses associated side fuel to0.7% points over the reference IGCC plant with cryogenic ASU. However, the trade-off 900°C and transport limitation. is the tighter integration and reduced flexibility of the plant. Also, the number of plant I This also required a separate to the OTM based ASU for O2 production a components is increased as in addition cryogenic ASU, but with smaller cryogenic ASU is required for N2 production. capacity. I Complete integration could lead to start-up/shut-down and availability issues. s s s s s s SINTEF Energy Research s s s s s s 20
    • Summary I An overview of the considerations when integrating an oxygen transport membrane as an ASU in an IGCC is presented. I An OTM with out sweep gas and 100% air integration is shown to have 0.7% points higher efficiency than the reference case cycle. I The trade-off is tighter integration - reduced flexibility. I Other cycles, e.g. combination of pre- and oxy-combustion concepts, are being evaluated. s s s s s s SINTEF Energy Research s s s s s s 21
    • AcknowledgementThe research leading to these results has received funding from theEuropean Community’s Seventh Framework Programme(FP7/2007-2013) under grant agreement nˇ 211971 (The DECARBit rproject). s s s s s s SINTEF Energy Research s s s s s s 22