Hybrid Electrochemical Hydrogen/Metal Hydride Compression Scott Greenway (PI), Martin Sulic, Aaron Wilber, Ted Motyka (GWE) Bruce Hardy, Anna d’Entremont (SRNL) George Roberts, Phillip Baker, Daryl Ludlow, Trent Molter (SI) Claudio Corgnale (GWE) - Presenter June 14, 2018 Project ID: PD137 This presentation does not contain any proprietary, confidential, or otherwise restricted information Overview Timeline and Budget Barriers • Project Start Date: 10/01/16 • Hydrogen Delivery barriers • Project End Date: 09/30/19 • Cost of high pressure large scale • Total Project Budget: $3750K hydrogen compression systems • Total Recipient Share: $752K • Efficiency of large scale compression • Total Federal Share: $2998K systems • Total DOE Funds Phase 1*: $1415K • Reliability of high pressure large * Phase 1 (18 months): end date 3/31/18 scale compression systems Partners (funded) • Savannah River National Laboratory (SRNL) • Sustainable Innovations (SI) • Greenway Energy (GWE) - lead 2 Relevance Project objective (Phase 1 & 2): Project achievements (Phase 1): Identify and build a two-stage hybrid thermo- • EHC configuration with Nafion® electrochemical compressor to achieve the membrane identified with stability DOE targets: demonstrated for 100 hours • Large scale hydrogen compression • Baseline MH materials • High operating pressures characterized at industrial level • Efficiencies equal to the DOE targets without performance degradation • Overall costs equal to the DOE targets demonstrated (so far) for 20 cycles • High reliability • Novel and effective configuration designs achieved for prototype and large scale compressor • EHC-MHC matching condition identified, achieving a thermally self MHC sustaining configuration with High pressure complete EHC heat recovery in the EHC MHC Low pressure • Viable path toward the DOE techno-economic targets identified DOE = US Department Of Energy MH = Metal hydride EHC = Electrochemical Hydrogen Compressor 3 MHC = Metal hydride Hydrogen Compressor Approach Project Phase 1 Integrated approach • Experimental tests • Hierarchical modeling • System models • Detailed models Identification of baseline effective and low cost configuration Phase 2 building and demonstration of the prototype db = Database MH = Metal hydride VI = Voltage-Current density EHC = Electroch. H2 Compr. BOP = balance of plant PCT = Pressure-Concentration-Temperature MHC = MH H2 Compr. DSC = Differential Scanning Calorimetry 4 ρ, Cp, k, ∆H, wt% = Density, specific heat, thermal conductivity, reaction enthalpy, weight capacity Approach-milestones Task 1.1: Screening analysis of candidate, hybrid compressor systems As of April Milestone 1.1.1: Development of a techno-economic modeling framework for evaluating MH and EC 2017 compression stages 12/31/16 - Complete Milestone 1.1.2: Successful identification of at least one system, operating at large scale, based on MH and EC technologies, demonstrating a viable path to reach the techno-economic targets reported in the DOE FOA 3/31/17 – Complete April 2018 Task 1.2: EHC bench scale experimental tests Experimental Milestone 1.2.1: Successful demonstration of the EHC bench scale system, being able to reach the characterization required operating conditions 9/30/17 - Complete Task 1.3: MH bench scale experimental tests Task 1.4: Hybrid compressor system model development and application Milestone 1.4.1: Successful demonstration of the technical feasibility of the selected hybrid compressor system under partial load and transient conditions 6/30/17 - Complete Hierarchical Task 1.5: MH tank detailed model development modeling Milestone 1.5.1: Detailed transport model results need to demonstrate that the proposed prototype system for partial load and transient conditions to be compared with experimental data during Phase 2. 12/31/17 - Complete Task 1.6: Hybrid Compressor prototype design Milestone 1.6.1 (Go/No-Go): Identification of at least one large-scale hybrid compressor system that Prototype meets the FOA techno-economic targets under steady state and nominal conditions and design of a design prototype. 03/31/18 - Complete MH = Metal hydride EC = Electrochemical 5 EHC = Electrochemical H2 Compressor Accomplishments and Progress EHC Pros Cons Previous status as of June 2017 membranes • Screening and database Nafion® • Commercially • Water handling available • Max T physical limit = population of EHC • Reliable and 190 °C (melting) consolidated membranes • Both Nafion and PBI PBI® • Higher T • Compatibility with PA • No water • Unknown long time membranes selected as handling reliability and stability possible candidates MHC Pros Cons • Screening and database materials population of MHC HP1 • Commercially • High hysteresis materials (Ti-Cr) available • High slope in the • Three Ti-based candidates 2phase region • High cost selected • ‘Low’ cost • Actual performance of • Additional Ti MHs HP2 downselected in conjunction (TiZr-Cr-Mn) • Low ∆H the industrial material • Available to be verified with SNL project HP3 • ‘Low’ cost • Operating conditions • Initial matching point (Ti-Cr-Mn) • Low ∆H of the industrial • Available material to be verified identified PBI = HP3 = Ti1.1CrMn SNL = Sandia National Lab MHC = Metal hydride compressor HP1 = TiCr1.9 6 EHC = Electrochemical H2 Compressor HP2 = (Ti0.97Zr0.03)1.1Cr1.6Mn0.4 High temperature PBI® vs Nafion® Advent PBI® membrane Nafion 117® membrane • Cost of chemical compatibility • Known systems suited for • SI projected a 4x cost of the pressurized water applications current Nafion® hardware • Membrane tests demonstrated • Material processing high hydration • Pressures suppress steam • Swelling of membrane during formation doping cased membrane to tear • Material stability and advantages • Demonstrated 100 hours operation at 130 °C < T < 190 °C • Potential for thickness reduction (so far Nafion 117 adopted) Advent TPS® membrane permeation • PA likely causes degradation Advent TPS® • Permeability variation doped Advent TPS® • Irrecoverable permeation Doped increase at higher differential pressures SI = Sustainable Innovations PBI = Polybenzimidazole 7 PA = Phosphoric acid Nafion EHC characteristic Nafion 117® membrane V-I characteristic 7 bar • Tests carried out so far at high temperatures (130-150 °C) and high pressures (up to 100 bar). • Operating current densities of 400 – 900 mA/cm2 gives possible matching points with the MHC • Future actions for performance improvement • Thinner membranes The EHC system based on • Membrane pretreatment at Nafion is technically feasible high T for higher water uptake • Redesign of the flow field for at 100 bar and 150 °C better gas distribution MHC = Metal hydride H2 Compressor EHC = Electrochemical H Compressor 8 2 Nafion EHC stability tests • Single cell tests for 95 hours at 500 mA/cm2 • Temperatures 130-150 °C • Pressures 15-101 bar Test Temperature Anode Cathode Point Pressure Pressure (°C) (bar) (bar) A 130 6.2 14.8 B 135 6.2 14.8 No performance C 140 6.2 14.8 degradation observed D 145 6.2 14.8 • Constant voltage at low E 150 6.2 14.8 pressure for > 40 hours F 150 6.2 121.7 • Constant voltage at high G 150 7.9 101.0 pressure for > 25 hours H 150 7.9 101.0 EHC = Electrochemical H Compressor 9 2 Nafion EHC model high T predictions Current Nafion 117® membrane V-I model characteristic • Model from Springer et al.* fitting T=150 °C the 10-100 bar data • Tests in progress for 170 °C (may be required by the MHC) and lower thickness membranes • Model predictions for 170 °C show feasibility and not appreciable efficiency variation P = 10-100 bar T = 170 °C MHC = Metal hydride H2 Compressor * Springer et al. JES, Vol. 138, No. 8, August 1991 EHC = Electrochemical H Compressor 10 2 MHC experimental apparatus • Small scale high pressure Sieverts’ for material PCT • Operating conditions • grams of MH • T up to ≈ 170 °C • P > 875 bar • Leak proofed • 2 channels in parallel • Results validated against LaNi5 experimental low P data (provided by ORNL) • Automated operation • Programmable regulator (1020 bar/15,000 psi max rating) • High-precision pressure transducers (0.01% FS; ±0.01 bar) • Pneumatic valves with negligible internal volume (40,000 psi rating) MHC = Metal hydride H2 Compressor FS = Full scale PCT = Pressure-Composition-Temperature ORNL = Oak Ridge National Lab 11 MH = Metal hydride MH experimental PCT data HP3 Material 170 °C 130 °C 110 °C Material Pros Cons Comment 80 °C (from JMC) 50 °C 22 °C HP3 Hysteresis; Low P Similar behavior (‘TiCrMn’) Plateau for HP2; New HP4 Hysteresis; Plateau; Alternative MH to (‘TiCrMnFe’) High P Low wt% HP2 and HP3 MHs characterization (XRD, SEM, etc) and treatment in progress HP4 Material ∆ 1000 Habs (kJ/mol) = 18.78 ± 0.13 120 °C ∆Sabs (J/molK) = 96.16 ± 3.05 ∆Hdes (kJ/mol) = 21.08 ± 0.69 ∆Sdes (J/molK) = 101.74 ± 15.97 80 °C 100 HP3 Material (bar) Pressure Abs_120C Des_120C Abs_80C Des_80C 10 0.00% 0.25% 0.50% 0.75% 1.00% 1.25% 1.50% Weight Fraction (%) PCT = Pressure-Composition-Temperature XRD = X-Ray Diffraction MH = Metal hydride SEM = Scanning Electron Microscope HP3 = High Pressure MH 3 (Ti1.1CrMn) HP2 = (Ti0.97Zr0.03)1.1Cr1.6Mn0.4 12 JMC = Japan Metal Co. HP4 = TiCr1.55Mn0.2Fe0.2 MH experimental properties and cycling • Complete cycling of commercial HP3 MH • Room temperature and pressures between vacuum and 150 bar • No observable performance degradation confirming literature data for AB2 MHs • Material physical and chemical properties measured experimentally HP3 Comment ρBulk 3300 Measured value, void (kg/m3) fraction about 50% k 0.75 – Powder MH value (W/mK)