DEVELOPMENT OF A 1 MWE SUPERCRITICAL CO2 BRAYTON CYCLE TEST LOOP The 4th International Symposium - Supercritical CO2 Power Cycles September 9-10, 2014, Pittsburgh, Pennsylvania Jeff Moore, Ph.D. SwRI Klaus Brun, Ph.D. SwRI Neal Evans SwRI Pablo Bueno, Ph.D. C.J. Kalra, Ph.D. SwRI GE GRC Acknowledgements: Richard Carlson Lalit Chordia Thar Energy Mark Lausten Levi Irwin U.S. Dept. of Energy Patrick Fourspring Ken Kimball Joseph McDonald Brian Morris Bechtel Marine 2 Project Objectives To develop a novel, high-efficiency supercritical CO2 turbo-expander optimized for the highly transient solar power plant duty cycle profile. – This MW-scale design advances the state-of-the-art of sCO2 turbo-expanders from TRL3 to TRL6. To optimize compact heat exchangers for sCO2 applications to drastically reduce their manufacturing costs. The turbo-expander and heat exchanger will be tested in a 1-MWe test loop fabricated to demonstrate component performance and endurance. Turbine is designed for 10 MW output in order to achieve industrial scale The scalable sCO2 expander design and improved heat exchanger address and close two critical technology gaps required for an optimized CSP sCO2 power plant Provide a major stepping stone on the pathway to achieving CSP power at $0.06/kW-hr levelized cost of electricity (LCOE), increasing energy conversion efficiency to greater than 50% and reducing total power block cost to below $1,200/kW installed. DOE established these goals to make CSP competitive with other energy sources 3 Project Approach Work has been divided into three phases that emulate development process from TRL3 to TRL6 Phase I – Turbomachinery, HX, and flow loop design (22 months) Phase II – Component fabrication and test loop commissioning (12 months) Phase III – Performance and endurance testing (6 months) 4 Test Loop Layout and Integration DOE selected 1-MWe test loop size which offers balance between cost and benefit The test loop layout has been designed with the intent of minimizing thermal stress, and maximizing use of existing infrastructure Loop piping and components will make use of the recently completed Turbomachinery Research Facility at SwRI The test loop is designed around the main and supporting components: expander, heater, pump, compressor, cooler, and dyno – Custom engineered air dynamometer will absorb the power produced by the expander during testing 5 Sunshot Goals The Sunshot program is funded by the Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy (EERE) SunShot office under the CSP power block Funding Opportunity Announcement (FOA). Co-funding is provided by our partners General Electric, Thar Energy, and Bechtel Marine. The thermal-to-electric efficiency of current CSP plants is 35 to 45% (DOE, 2012). The goal of this program is to meet these aggressive performance and cost goals: – Net cycle efficiency > 50% – Dry cooled – Cost < $1,200/kWe Project Work Breakdown Southwest Research Institute (SwRI) in collaboration with General Electric and Thar Energy was awarded a Phase I award on the design and development of these tasks: Design Supercritical CO2 Brayton Cycle Power block to achieve FOA goals Proposed modular power block in 10 MWe range to meet CAPEX targets Compact power block for pre-fabricated tower mounted operation SwRI scope includes test loop design and operation, assist GE with expander engineering, manufacturing drawings, and expander fabrication. GE is responsible for the power block design, thermo-economic analysis, and test loop cycle design. GE to design the sCO2 turbo-generator to meet FOA targets. Thar Energy to design recuperator for the power block meeting the FOA efficiency and cost targets. – 30% reduction in recuperator cost from current state-of-the-art Project Work Breakdown Schedule • • • • 22 months 12 months 6 months Phase 9/12 – 7/14 Phase 2 8/14 – 8/15 Phase 3 8/15 – 2/16 Test loop design & component/vendor identification (1 MWe) • Expander engineering • Expander assembly and shakedown testing Expander testing off-design at 1MWe scale. (1 MWe) • Recuperator testing at 5MW-th scale. • Test loop and expander manufacturing drawings Recuperator design and bench scale testing Test loop fabrication Expander fabrication • Recuperator fabrication. • • Test loop assembly Recompression sCO2 Cycle Simple sCO2 Recuperated Cycle for Test Loop Loop Operating Conditions Component T out (°C[°F]) P out (bar [psi]) Flow (kg/s [lb/s]) Pump 29.22 [84.60] 255.0  Recuperator-Heat 470.0 [878.0] 252.3  Heater 715.0  250.9  Expander 685.7  86  Recuperator-Cool 79.58 [175.2] 84  PreCooler 10.00 [50.00] 83  9.910 [21.85] 8.410 [18.54] 9.910 [21.85] Pipe Specifications Section NPS Schedule Thickness Predicted V (ft/s) A106B 13.07 Material Flanges Pump out 3 XXS 0.6 Mixing line 1.5 XXS 0.4 316s 28.56 Recuperator hot out 3 XXS 0.6 316s 59.19 ANSI 2500# ANSI 2500# Grayloc Heater out 3 160 0.438 Inco 625 62.26 Grayloc Heater out dual 2.5 160 0.375 Inco 625 47.47 Grayloc Expander out double 3 160 0.438 Inco 625 84.73 Grayloc Recuperator cool out 3 160 0.438 A106B 54.13 6” to cooler 6 160 0.718 A106B 13.84 Cooler out 8 120 0.718 A106B 1.37 Pump inlet 4 120 0.437 A106B 5.39 ANSI 1500# ANSI 1500# ANSI 900# ANSI 900# P&ID Equipment List Component Pump Recuperator Heater Blower Expander Dynamometer Chiller Loop throttle Compressor recycle Cooler bypass Dilution valve Dyno suction valve Dyno discharge Cooling water bypass Flow meter V-cone Strainer Relief valve Relief valve Relief valve Relief valve Symbol PUMP RCP HTR BLWR EXP DYNO CHLR CV-01 CV-02 CV-03 CV-04 CV-05 CV-06 TV-01 ORF V-CONE STR PSV-01 PSV-02 PSV-03 PSV-04 Description sC02 pump: GE Nuovo Pignone Heat exchanger: Thar Energy Gas-fired heater: Thar Energy Heater air supply blower sC02 turbine: GE Load absorbing centrifugal compressor: SwRI 800 gpm cold water Main loop throttle control valve sC02 pump recycle control valve Existing 3” Dyna-Flo, 900# process bypass Mixing valve to control RCP-H inlet temp. Dyno compressor suction throttle valve Dyno compressor discharge throttle valve Existing 3-way cooling water bypass hand valve Orifice plate flow meter Flow meter 4” Y-strainer Set pressure = 4000 psig Set pressure = 4000 psig Set pressure = 1975 psig Existing 2x3”, set pressure = 1975 psig Test Loop Process and Instrumentation Diagram Comparison of CO2 Density – Stoner Pipeline Simulator and REFPROP Device P (psia) T (°F) Pump out 3697.91 LT-HTR out Density [lb/ft3] Error Stoner REFPROP 143.17 49.387 48.883 1.03% 3690.28 356.90 22.9 22.554 1.53% RCP 1 out 3681.14 988.00 10.306 9.9871 3.19% HT-HTR out 3678.02 1320.00 8.259 8.0043 3.18% EXP out 1213.73 1190.00 3.014 2.9711 1.44% RCP 2 out 1205.08 366.10 6.621 6.5232 1.50% CLR out 1204.00 86.00 47.988 44.789 7.14% Predicted Nozzle Loads Fx (lb) Fy Fz Mx (ft-lb) My Mz RCP-C in 66 -50 -120 -144.3 -130.8 -89 RCP-H out 74 -305 -129 456.2 48.7 -185.4 HTR in 17 -92 -85 143.4 290.4 -253.4 HTR out 305 605 -252 -325.4 1166.5 490.7 EXP in, top 670 -143 -143 -105.6 -457 -777.2 EXP in, bottom -365 -149 -109 53.1 -393.1 -477.7 EXP out, top 333 898 -170 -1613.1 175.1 164.8 EXP out, bottom 102 -781 -82 1414.5 121.9 -618.3 RCP-H in, top 232 -2537 101 2405 -386.2 287.4 RCP-H in, bottom 118 2271 -94 -2334.2 -292.2 -522.7 RCP-C out 55 169 165 195.3 -686.6 457.4 Stoner Pipeline Simulator Model Schematic Existing Facility Piping and Expander Piping Expander Piping Detail Existing 3 MW CO2 Compressor Existing CO2 Pipe Loop Conclusions • Design of a high-pressure, high-temperature SCO2 flow loop has been completed to measure the mechanical and flow performance of a custom SCO2 turbine expander and recuperator. • The flow capacity of the loop is equivalent to a 1 MWe size. • Test loop provides a platform to perform mechanical and performance testing of the expander and recuperator. • The test loop design has sized the pipe to maintain acceptable flow velocities and pressure drop. • A thermal piping analysis was performed to demonstrate acceptable pipe loading on the expander and recuperator nozzles. • All of the test loop design objectives were satisfied. • Manufacturing will commence in Phase 2 of the program.
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