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On-Site Hydrogen Production From High-Pressure Liquids NHA Hydrogen Conference and Expo Ben Oster May 5, 2010
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Outline Introduction Objectives Hydrogen Production Flow Diagram and Results Future Work Conclusions
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Introduction High pressure reactor system –Distributed hydrogen production –Converts liquid reactants directly to high pressure hydrogen Pump liquid reactants into reactor operating at 6000 to 12,000psi Purify hydrogen at system pressure (6000 to 12,000 psi) NOT REQUIRED REDUCED
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Compression Energy Savings Percent of Hydrogen LHV Storage → Source ↓ 3626 psia 5076 psia 7252 psia 10,153 psia 15 psia13.2%14.3%15.5%16.7% 102 psia7.8%8.8%9.8%10.9% 290 psia5.6%6.5%7.4%8.4% 1958 psia1.7%2.5%3.3%4.2% Source: Air Products and Chemicals, Inc.
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Mass of Hydrogen Per Delivery Basis: 7500 gal Transport Tank
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Hydrogen Pipeline Challenges Least expensive way to transport large amounts of hydrogen [1] Existing hydrogen pipeline is 0.33% of natural gas pipeline in length with only 200 delivery points [2] $1.2 million/mile (transmission) and $0.3 million/mile (distribution) [3] Advancements could decrease costs >50% [4] Distributed hydrogen generation provides a near term solution
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Objectives of On-Site Hydrogen Production from Liquids Circumvent hydrogen pipeline to allow near-term H 2 fueling stations. Transport liquid feedstocks to take advantage of existing fuel infrastructure while gaseous/liquid H 2 infrastructure develops. Avoid or reduce compression requirements with pressurized production.
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Hydrogen Production Flow Diagram
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Lab Scale Hydrogen Production System Continuous reactor system utilizes supercritical water Rated to 1,200ºF and 12,000psig; typically 0.2 kg hydrogen per hour
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Ethanol On-site hydrogen generation from ethanol –Ethanol is an available and renewable feedstock –Crude ethanol/water mixture could be a less expensive feedstock Long term data needed to study catalyst activity over time Potentially cheaper due to less processing at the ethanol production facility Water is a non-issue as it is a required reactant Other contaminants need to be examined more closely with respect to potential plugging & coking issues
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Results – Refined Ethanol EthanolMole % of dry product gas T, ºCP, psiH2H2 CO 2 COCH 4 CxHyCxHy Conversion 467536351230.619595% Desired reaction: C 2 H 5 OH + 3H 2 O 6H 2 + 2CO 2 Hydrogen max = 75mole% Competing reactions lead to methane formation
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Glycerol On-site hydrogen generation from glycerol –Glycerol is a biodiesel byproduct accounting for 10% of total product at a biodiesel facility –Refining bottleneck = stable price for refined glycerol –Crude glycerol could be a cheap, abundant, renewable feedstock for hydrogen production Long-term data needed Study contaminants’ affect on catalyst activity over time Contaminants include water, salt, organic matter
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Results – Refined Glycerol GlycerolMole % of dry product gas T, ºCP, psiH2H2 CO 2 COCH 4 CxHyCxHy Conversion 541483860311.15.80.793% Desired reaction: C 3 H 5 (OH) 3 + 3H 2 O 7H 2 + 3CO 2 Hydrogen max = 70mole% Competing reactions
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Methanol Methanol is currently synthesized from natural gas Methanol can be synthesized from renewable biomass Methanol is a simple molecule and reforms completely at high pressures and relatively low temperatures
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Results - Methanol MethanolMole % of dry product gas T, ºCP, psiH2H2 CO 2 COCH 4 CxHyCxHy Conversion 384488573250.50.90.01100% Desired Reaction: CH 3 OH + H 2 O 3H 2 + CO 2 Hydrogen max = 75mole%
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Hydrogen Production Flow Diagram
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Water Removal Water is fed in excess of stoichiometric. –Avoid coking of catalyst –Provide process heat Need to remove water. Critical temperature (T c ) of water = 374°C. Cooling below T c causes phase change to liquid. –Cooling water used for heat exchange Removed via level control and a valve at the bottom of the condensate vessel. Works very well.
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Hydrogen Production Flow Diagram
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CO 2 Removal CO 2 is continuously removed via selective absorption. The resulting product gas composition approaches 96 mole% hydrogen with the balance being methane and carbon monoxide. A final, high pressure gas purification step is required to purify the gas to PEM fuel cell quality.
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Hydrogen Production Flow Diagram
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Electrical Swing Adsorption (ESA) Objective is to purify the hydrogen rich gas stream to PEM fuel cell quality at 6,000-12,000psig. Tailoring an ESA process, developed by Oak Ridge National Lab, for high pressure. Involves gas separation in an electrically conductive monolith. Non-hydrogen gases adsorb on the monolith, whereas hydrogen passes through; results in hydrogen separation. Similar to pressure swing adsorption but does not require a drop in pressure to release contaminants. Release contaminants by applying an electric current.
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ESA Test System
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Electrochemical H 2 Purification H+H+ H2H2 H2H2 H 2, CO, H 2 O, CO 2 CO 2 2H + + 2e - H 2 H 2 2H + + 2e - CO + H 2 O CO 2 + 2H + + 2e - Cathode Chamber Anode Chamber Cathode Electrolyte Anode Principle Anode reactions: CO + H 2 O CO 2 + 2H + + 2e - E o = -0.106 V; H 2 2H + + 2e - E o = 0 V Cathode reaction: 2H + + 2e - H 2 E o = 0 V Total Reactions: CO + H 2 O CO 2 + H 2 E o = 0.106 V H 2 H 2 E o = 0 V High-purity H 2 can be obtained at the cathode side with low energy consumption.
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Fully Automatic Controlled High-Pressure Electrochemical H 2 Purification Unit
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Hydrogen Production Flow Diagram
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Scaled-up, Integrated System: Projected H 2 delivery rate of 0.6 kg/hr PREHEATER FEED STORAGE TANKS REFORMER REACTOR DISPENSING CO 2 REMOVAL H2H2 HYDROGEN PURIFICATION STORAGE
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Future Work Finalize construction and shakedown of scaled-up, integrated hydrogen production unit. Demonstrate hydrogen production with scaled-up unit. Continue to study other reformer feedstocks. Continue to develop high pressure gas purification technologies.
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Conclusions High pressure liquid reforming offers a distributed hydrogen platform that has unique advantages. Renewable liquids have been converted to 6000psi hydrogen in the lab. A scaled up unit is being fabricated to demonstrate integrated high pressure hydrogen production, purification, and dispensing.
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Acknowledgements U.S. Army Corps of Engineers, Engineer Research Development Center, Construction Engineering Research Laboratory (ERDC-CERL) National Center for Hydrogen Technology (NCHT) sponsored by the U.S. Department of Energy (DOE) National Energy Technology Laboratory (NETL)
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Thank You
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Cited Sources [1] DOE Hydrogen Program. Hydrogen distribution and delivery infrastructure. Fact Sheet. http://www.hydrogen.energy.gov/pdfs/doe_h2_delivery.pdf [2] The Impact of Increased Use of Hydrogen on Petroleum Consumption and carbon Dioxide Emissions. August 2008. Energy Information Administration. Office of Integrated Analysis and Forecasting, Office of Coal, Nuclear, Electric and Alternative Fuels. US Department of Energy. Washington, DC 20585. [3] See U.S. Department of Energy, Energy Efficiency and Renewable Energy, Hydrogen, Fuel Cells & Infrastructure Technologies Program: Multi-Year Research, Development and Demonstration Plan, Table 3.2.2 (Washington, DC, October 2007), www1.eere.energy.gov/hydrogenandfuelcells/mypp. [4] B. Smith, B. Frame, L. Anovitz, and T. Armstrong, “Composite Technology for Hydrogen Pipelines,” in U.S. Department of Energy, Hydrogen Program, 2008 Annual Merit Review Proceedings, www.hydrogen.energy.gov/annual_review08_proceedings.html
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