hydrogen technology (05) - hydrogen properties and … · (iso/tr 15916:2004). the solidified gases...

Hydrogen Technology (05)- Hydrogen Properties and Its Safety

薛康琳，Kan-Lin Hsueh國立聯合大學、能源工程學系/所National United University, Department of EnergyEngineering

Kan-Lin Hsueh, 2013/2/2Hydrogen Technology (02) - Hydrogen

Properties and Its Safety 1

February 2, 2013

Sources:V. Molkov, “Fundamentals of Hydrogen Safety Engineering”, bookboon.com, Ventus Publishing Aps ISBN 978-87-403-0226-4 (2012)

Outline Type of hydrogen Gas, liquid, solid phase Boiling point, melting

point, boil-off Hydrogen storage and

transfer Physical properties Joule-Thomson effects Ideal, non-ideal gas

Kan-Lin Hsueh, 2013/2/2 Hydrogen Technology (02) - Hydrogen Properties and Its Safety 2

Sources: V. Molkov, “Fundamentals of Hydrogen Safety Engineering”, bookboon.com (2012)

Heat of combustion Flammability Ignition Quenching Detonation Deflagration Comparison to other gases

Hydrogen is the most abundant element in the Universerepresenting 75% by mass or 90% by volume of allmatter. Hydrogen form 0.15% of the earth crust.

Three hydrogen isotopes: Protium (氕) Deuterium (氘) Tritium (氚)

Hydrogen is colorless, odorless, and insipid. Hydrogen leak is difficult to detect. Compounds such as

mercaptan (CH3SH), which are used to scent natural gas,cannot be added to hydrogen for use in PEMFC.

General



Physical and Chemical Properties- Types of Hydrogen

Three hydrogen isotopes:

The hydrogen molecule exists in two forms Ortho-hydrogen (the spin direction of nuclear is in the same

direction) Para-hydrogen (the spin direction of nuclear is in the

opposite direction)



Type of hydrogen Amount # of proton in nucleus

1 Protium (氕) 99.985% 1

2 Deuterium (氘) 0.015% 2

3 Tritium (氚) trace 3

Physical and Chemical Properties- Heat Released between Ortho- and Para-hydrogen



Equilibrium mixture of ortho- and para-hydrogen at anytemperature is referred to as equilibrium hydrogen.

Ortho-H2 Para-H2 + 703 kJ/kg @ 20 K Normal H2 Para-H2 + 527 kJ/kg @ 20 K Hydrogen is safer to store as cryo-compressed rather than

liquefied fluid. fluids with temperatures below–73 C are known as cryogenic fluids. In automotive applications, due to essential reduction if not exclusion at

all of the hydrogen boil-off phenomenon at day-to-day normal driving.

Ortho-hydrogen Para-hydrogen

@ room temp. Normal hydrogen 75% 25%

@ 20 K 0.2% 99.8%

Physical and Chemical Properties- Gas, liquid, and solid phases


Sources: V. Molkov,“Fundamentals of Hydrogen Safety Engineering”, bookboon.com (2012)

Freezing

Condensation

Deposition

13.8 K, 7.2 kPa

33.15 K, 1.3 Mpa31.263 kg/m3

Normal melting point: 14.1 KNormal boiling point: 20.3 K

Physical and Chemical Properties- Boiling point, melting point, and density ofhydrogen

The NBP (normal boiling point @ 101.3 MPa) ofhydrogen is 20.3 K.

The NMP(normal melting point @ 101.3 MPa) ofhydrogen is 14.1 K.

Hydrogen Density The density of liquid para-hydrogen is 70.78 kg/m3. Hydrogen density at NTP is 0.0838 kg/m3 which is far

below than air density of 1.205 kg/m3 at the samecondition.

The specific gravity of liquid para-hydrogen is 0.071. Every 1 m3 water contains 111 kg of hydrogen.



Physical and Chemical Properties- Definition of Boil-off

A cryogenic fluid is typically kept at low temperatures ina storage vessel. The storage has a major challenge dueto the inherent heat input from

The effect of the heat input is warming of the cryogenicfluid: If (constant volume) Pressure increase in the storage vessel If (constant pressure)Fluid boils and “boil-off” vapors are

released from the vessel (venting) The vapors created due to the ambient heat input (while

maintaining constant pressure in the storage vessel) arecalled “boil-off”. The discharge of these vapours out of the storage container is

called venting.


Sources: Mihai Ursan (WestPort), “What is Boil-off?”, LNG Task Force meeting in Brussels, November 3, 2011

Physical and Chemical Properties- measurement of Boil-off

The measure for the boil-off is the amount of vapours perunit time –boil-off rate.

It can be an absolute measure –kg/h, kg/day or a relativemeasure –% vaporized from total amount per unit time.

For example For a laboratory vessel holding liquid nitrogen, the boil-off rate may be

0.01 kg/h. For the natural gas peak-shaving plant storage tank the boil-off rate

may be 0.05%/day. The boil-off rate can be used determine how long you can

hold the cryogenic fluid in the specific container. For the laboratory vessel, the cryogen will be vented in 50 hours

(assume vessel capacity is 5 kg of liquid) and for the peak-shavingplant storage the whole content will be processed in 2000 days = 5.5years.


Sources: Mihai Ursan (WestPort),“What is Boil-off?”, LNG Task Force meeting in Brussels,November 3, 2011

Physical and Chemical Properties- Boil-off in the vehicle LNG Tank

LNG is a cryogenic liquid stored in a tank on-board thevehicle. Inherently heat from ambient flows in and warms theliquid.

For this application, the tanks are designed to take higherpressure, therefore being able to contain the LNG withoutrelease of vapor.

The time the tank can hold the LNG without venting is called“holding time”. By codes in US and Canada the holding time is 5 days.



Physical and Chemical Properties- Heat management and types of fuel delivery systems

Dealing with the amount of heat accumulated in the tank depends onthe fuelling station and vehicle application.

Among other references available in the industry, there has a goodpresentation of fuel delivery systems. Two types of delivery systems:vapor collapse system and vapor return system. (see above reference)



Physical and Chemical Properties- Vapor Collapse System The delivery pressure is

below the tank maximumworking pressure.

The vehicle tank is equippedwith an “economizer”that iscapable to draw vapors fromtank. It maintains the tankpressure constant.


At the fuelling station, cold LNG is sprayed on top of thetank and the temperature of the residue vapor in the tank islowered until vapor condenses (collapse). This reduces thepressure in the tank allowing it to be re-fuelled.


Physical and Chemical Properties- Vapor Return System of Boil-off

The delivery pressure is above thetank maximum working pressure.

The fuel system has a pump thatdraws liquid and pressurize it. Thepressure in the tank may decrease,maintain steady or increasedepending on the rate the fuel isdrawn out of the tank. Frequent cases are of pressure

increase in the LNG tank


At the fuelling station cold LNG is sprayed on top of the tank anddepending on the initial condition of the tank, vapors in the tankmay or may not collapse. When there is a pressure increase,vapors are transferred to the fuelling station. This reduces thepressure in the tank allowing it to be re-fuelled.


Physical and Chemical Properties- Hydrogen Storage and Transferred

Liquid para-hydrogen (NBP) has a density of70.78 kg/m3. The corresponding specific gravityis 0.071. Hydrogen density in water is 111 kg/m3.

Leaks of air or other gases into direct exposurewith liquid hydrogen can lead to several hazards(ISO/TR 15916:2004). The solidified gases canplug pipes and orifices and jam valves.

Liquid hydrogen is usually transferred in vacuuminsulated lines.



Physical and Chemical Properties- Hydrogen Storage and Transferred

Cold hydrogen flowing through tubes which are notsufficiently thermal insulated can easily cool the systembelow 90 K so that condensed air with an oxygen contentof up to 52% is present (NBP of N2 is 77.36 K, O2 is90.15 K, CO2 is 216.6 K).

The liquid condensate flows and looks like liquid water.This oxygen-rich condensate enhances the flammabilityof materials and makes materials combustible that normalare not.

Vessel with liquid hydrogen have to be periodicallywarmed and purged to keep the accumulated oxygencontent in the vessel to less than 2% (ISO/TR15916:2004)



Physical and Chemical Properties- Buoyancy as Safety Asset for Hydrogen

Hydrogen has the highest buoyancy on earth. Hydrogen canrapidly flow out of an incident scene, and mix with theambient air to a safe level below the lower flammability limit(LFL) of 4% by volume of hydrogen in air.



Physical and Chemical Properties- Diffusivity and Viscosity

Diffusion coefficient 6.110-5 - 6.810-5 m2/s in air 1.410-5 through gypsum panel at 22 C 4.510-9 m2/s in water

Diffusion coefficient of other gases Oxygen in water 2.010-9 m2/s

Viscosity Gas: 89.48 poise (NTP), 11.28 poise

(NBP) Liquid: 132.0 poise Air 18.1 Pa.s (kg/(m.s)) @ 15 C Water 1.0 centipoise ( m Pa.s) @ 20 C



Physical and Chemical Properties- Specific Heat and Thermal Conductivity

Specific heat Gaseous hydrogen, Cp (kJ kg-1 K-1) is 14.85 (NTP), 14.304 (STP), 12.15

(NBP) Liquid hydrogen, Cp (kJ kg-1 K-1) is 9.66. Liquid water, Cp (kJ kg-1 K-1) is 4.1855. Water vapor, Cp (kJ kg-1 K-1) is 1.996.

Thermal conductivity Gaseous hydrogen (W m-1 K-1 ) is 0.187 (NTP), 0.01694 (NBP) Liquid hydrogen (W m-1 K-1 ) is 0.09892 (NBP)



Physical and Chemical Properties- The Joule-Thomson Effect



HPT

Joule-Thomson Coefficient

Isenthalpic curve, constant enthalpy

Slope of the curve = J-T coefficient

Locus of the inversionpoints 0

Physical and Chemical Properties- Ideal and Real Gas Equations



For non-idea gas(Abel-Noble equation)

TRZP

TRP H 2

RH2 = 4124.24 J kg-1 K-1

= R = 8.3145 J mol-1 K-1

For idea gas

TR

TRVn

P

TRnVP

Compressibility factor, Z)1331069.7,

11

kgmbb

Z

Z = 1.01 @ 1.57 M Pa (15.7 bar, ~ 15.7 atm)Z = 1.1 @ 15.7 M PaZ = 1.5 @ 78.6 M Pa

Combustion Properties- stoichiometric mixture, heat of combustion

Hydrogen burns in a clean atmosphere with an invisible flame (~2403 K). The stoichiometric concentration of hydrogen in air (21% O2, 79% N2) is

29.59% by volume (2/(2+1+3.76)=0.2959) with air content of 70.41%. Heat of combustion of hydrogen is 241.7 kJ mole-1 (LHV), 286.1 kJ mole-1

(HHV)



22222

222

76.3276.3222

NOHNOHOHOH

Combustion Properties- Flammability, temperature & pressure effect


Sources: V. Molkov,“Fundamentals of Hydrogen SafetyEngineering”, bookboon.com (2012)

Combustion Properties- ignition



The ignition energy of hydrogen-air mixture varies with its composition.Less energy is needed to ignite a mixture that is closer to its stoichiometriccomposition. The minimum ignition energy (MIE) is 0.017 MJ for the mostignitable mixture.

The standard auto-ignition temperature of hydrogen in air is above 510 C.Hot air jet ignition temperature is 670 C.

Combustion Properties- burning velocity

Laminar burning velocity and flame propagation speed



t

vu E

SS

Su : laminar burning velocitySv : propagation velocity of spherical flameEt : expansion coefficient, the ratio of the unburned

mixture density to the density of combustionproducts at the same pressure.

The maximum possible flamepropagation speed, i.e. deflagration frontvelocity relative to a fixed observer, isgiven by the speed of sound in thecombustion products, 975 m/s for astoichiometric hydrogen-air mixture.

Combustion Properties- quenching

Quenching of any flame occurs when heat losses from flame are comparable with heatgeneration due to combustion, and then the chemical reactions cannot be sustained.

Usually quenching distance is reported as the minimum pipe (or hole) diameter throughwhich a premixed flame can pass. The quenching gap in air for hydrogen is 0.64 mm.The quenching distance decreases with increase of pressure and temperature. Thelowest reported quenching distance for hydrogen is 0.076 mm. Gasoline quenchingdistance is 2.0 mm.

Hydrogen has the narrowest maximum experimental safe gap (MESG) of 0.08 mm toprevent premixed flame propagation out of a shell, composed of two hemisphericalparts, through the gap between flanges of these hemispheres.



Substance Methane Propane Ethylene Acetylene Hydrogen

MESG, mm 1.14 0.97 0.65 0.25 0.28

Combustion Properties- detonation The detonability range is 18-59 v/o of Hydrogen in air. Detonation velocity is around 1980 m/s. Deflagration to detonation transition (DDT) refers to a phenomenon in

ignitable mixtures of a flammable gas and air (or oxygen) when a suddentransition takes place from a deflagration type of combustion to a detonationtype of combustion.



Combustion Properties- deflagration to detonation



A deflagration is characterized by a subsonic flame propagation velocity,typically far below 100 m/s, and relatively modest overpressures.

A detonation is characterized by supersonic flame propagation velocities,perhaps up to 2000 m/s, and substantial overpressures, up to 20 bars.

Physical Properties- comparison with other fuels



Physical Properties- health hazards



OxygenConcentration

Stage of asphyxiation

15–19 % decreased ability to perform tasks; may induce early symptoms inpersons with heart, lung, or circulatory problems

12–15 % deeper respiration, faster pulse, poor coordination

10–12 % Giddiness, poor judgment, slightly blue lips

8–10 % Nausea, vomiting, unconsciousness, ashen face, fainting, mentalfailure

6 - 8 % Death in 8 min (50% death and 50% recovery with treatment in 6min, 100% recovery with treatment in 4 to 5 min)

4 % Coma in 40 s, convulsions, respiration ceases, death

Hydrogen Technology (06)- Overview of Hydrogen Production

薛康琳，Kan-Lin Hsueh國立聯合大學、能源工程學系/所National United University, Department of EnergyEngineering

Kan-Lin Hsueh, June 13, 2013 Production of Hydrogen 1

June 13, 2013


Hydrogen Consumption Pattern in USA in 1974

PetroleumRefining

47%

AmmoniaSynthesis

36%

MethanolSynthesis

10%

MiscellaneousUses7%

1 quad (1015 BTU)/year

Tilak et. al., “Electrolytic Production of Hydrogen”, in “Comprehensive Treatise of Electrochemistry, vol.2, Electrochemical Processing”, Plenum Press (1981)


Current Merchant DemandD. Fraser, “Solution for Hydrogen Storage and Distribution”, The PEI Wind-Hydrogen Symposium, June 22-24, 2003


Hydrogen Production TodayD. Fraser, “Solution for Hydrogen Storage and Distribution”, The PEI Wind-Hydrogen Symposium, June 22-24, 2003

SuperGrid - today


Sources: P.M. Grant, C.S.tarr and T.J. Overbye, “A Power Grid for the Hydrogen Economy”, Scientific American July (2006) p78-83

SuperGrid –10 years later



SuperGrid –25 years later



Overview of the Transition to the Hydrogen Economy,US DOE (2002)


Sources:A National Vision of America’s Transition to a Hydrogen Economy–to 2030 and Beyond, US DOE report (2002)

Hydrogen Densities of Materials


Korea H&FC Roadmap and Vision (2006)


Sources: Y-S Kim, “Hydrogen and Fuel Cell Activities in Korea”, The 5th IPHE Steering Committee Meeting,Vancouver, Canada (2006)

H&FC Current Status of R&D in Korea (2006)



H&FC R&D Performance in Korea (2006)



Hydrogen Production - promising technologies

Thermal Processes Distributed natural gas reforming Bio-derived liquid reforming Coal and biomass gasification

Electrolytic Processes Water electrolysis

PEM water electrolysis Alkaline water electrolysis High temperature water electrolysis

Photolytic Processes Photoelectrochemical hydrogen production Biological hydrogen production


Hydrogen Production Overview of Technology Options, Freedom Car and Fuel PartnershipFrom: https://www1.eere.energy.gov/hydrogenandfuelcells/pdfs/h2_tech_roadmap.pdf

Sources:A National Vision of America’s Transsition toa Hydrogen Economy–to 2030 and Beyond, US DOEreport (2002)

Proposed Timeframes to Market



Hydrogen Production from Natural Gas Reforming


Auto-thermal ReformingCH4 + O2 CO2 + 2 H2

Steam ReformingCH4 + 2 H2O CO2 + 4 H2


Bio-derived Liquid Reforming


CO2 + 12 H2O 6 O2 + C6(H2O)6

Harvest Pretreatment Carbohydrates

Sugar AlcoholAqueous-

PhaseReforming

Hydrogen


Coal and Biomass Gasification


C + 2 H2O CO2 + 2 H2


Hydrogen from Coal –case 1 - 3


Source: D.Gray, G.Tomlinson, “Hydrogen From Coal”, Mitretek Technical Paper (2002) contract from USDOE NREL

ASU: Air Separation UnitPSA: Pressure Swing AdsorptionHRSG: Heat Recovery Steam Generator

Hydrogen from Coal –case 4 –6, coproduction



CC: Carbon CapturePSA: Pressure Swing AdsorptionHRSG: Heat Recovery Steam GeneratorCOE: Cost of Electricity

Hydrogen from Coal –case 7 & 8, using SOFC


Source: D.Gray, G.Tomlinson, “Hydrogen From Coal”, Mitretek Technical Paper (2002)contract from US DOE NREL

CC: Carbon CaptureHGCU: Pressure Swing AdsorptionHRSG: Heat Recovery Steam GeneratorCOE: Cost of ElectricityHGCU: Hot Gas CleanUp

Hydrogen from Coal –case 9& 10, using SOFC



CC: Carbon CaptureHGCU: Pressure Swing AdsorptionHRSG: Heat Recovery Steam GeneratorCOE: Cost of ElectricityHGCU: Hot Gas CleanUp

Summary of Hydrogen from Coal Cases


Case 1 Case 2 Case 3

Carbon Sequestration NO YES (87%) Yes (100%)

Hydrogen, MMSCFD 131 119 158

Coal T/D, (AR) 3,000 3,000 3,000

Efficiency, (%HHV) 63.7 59 75.5

XS Power, MW 20.4 26.9 25

PowerValue, (MILS/kWh) 35.6 53.6 53.6

Capital, $MM 367 417 425

RSP of Hydrogen, $/MMBTU 6.83 8.18 5.89

Source: D.Gray, G.Tomlinson, “Hydrogen From Coal”, MitretekTechnical Paper (2002) contract from US DOE NREL

MMSCFD: Million Standard Cubic Feet per Day, 106 ft3/dayT/D: Ton per DayAR: As Received, including total moistureHHV: High Heating ValueRSP: Recommended Selling PriceMMBTU: Million British Thermal Unit, 1 BTU = 1055 J

Summary of Co-production Cases


Case 4 Case 5 Case 6

Carbon Sequestration No Yes (95%) Yes (100%)

Hydrogen, MMSCFD 149 153 153

Coal T/D, (AR) 6,000 6,000 6,000

Efficiency, (%HHV) 62.4 56.5 59

XS Power, MW 475 358 416

PowerValue, (MILS/kWh) 35.6 53.6 53.6

Capital, $MM 910 950 950

RSP of Hydrogen, $/MMBTU 5.42 5.64 3.98



Summary of Cases Using SOFC Systems


Case 7 Case 8 Case 9 Case 10

Carbon Sequestration No Yes (98%) Yes (90%) Yes (95%)

Hydrogen, MMSCFD 0 0 149 150

Coal T/D, (AR) 3,000 3,000 6,000 6,000

Efficiency, (%HHV) 65.7 61.3 64.5 65.2

XS Power, MW 567 529 509 519

PowerValue, (MILS/kWh) 33.7 41.0 53.6 53.6

Capital, $MM 628 717 1,037 1,019

RSP of Hydrogen, $/MMBTU NA NA 2.79 2.40



Thermochemical Production


Separation(filtration and drying)

ZnO

ThermalDecomposition

2 ZnO 2 Zn + O2

Metal-water reactionZn + H2O ZnO + H2

Solar Reactor, heated to about 1,900 C

O2

H2O

H2

ZnO

Zn

ZnO


Electrolytic Water Splitting: Partial Reactions


Sources: T. Smolinka, J.Garche, C.Hebling, O.Ehret, “Overview on Water Electrolysis for Hydrogen Production and Storage”, Symposium - Water Electrolysis and Hydrogen asPart of the Future Renewable Energy System, Copenhagen/Denmark, May (2012)

Photoelectrochemical Hydrogen Production



The Difference between PEC (Photo-Electrochemical Cell) and Solar Cell

SolarEnergy

Solar CellElectricity

Chemical Energy(Battery)

Electricity

SolarEnergy

PECChemicalEnergy (Fuel) Electricity

Fuel Cell


Operation Modes of PEC

Energy Conversion

SolarEnergy

PEC ChemicalEnergy(Fuel)

Electricity

Fuel Cell

Photo-Assisted Electrolysis

SolarEnergy

PEC

Chemical Energy (Chemicals)

Electricity


Basic Principle of PEC

Semi-conductingMaterial

e-

+

AqueousSolution

Red

Ox

Ox + e- Red

Semi-conductingMaterial

e-

+

AqueousSolution

Red

Ox

Red + e- Ox


Solar Spectrum

(m) = 1.24 /h(eV)

1 2 3 eV

dnph

/dh

0 h

h

e-

Eg

Ec

Ev


Conversion Efficiency

1 2 3 eVn p

h

0 h

EgEm

=

= 30%for Em=0.9,Eg=1.35 eV

Vm Voc

ILIm

e-

hEgEc

Ev

qVoc


Integrated Electricity/Storage Systems

MoSe2 Stabilized by I- 10% Efficient Requires Recycling of I2 No Step Edges on MoSe2

HII

H2

2

MoSe2 M

e

HBr

Br H22

Uses Si IC Technology 6-7% Efficient Requires Recycling of Br2

Si


Photoelectrochemical CellLight is Converted to Electrical+Chemical Energy

metal

e-

e-

O2

H2O

H2

H2O

e -

h +

LiquidSolid

SrTiO3


Photoelectrochemical CellLight is Converted to Electrical+Chemical Energy

metal

e-

e-

O2

H2O

H2

H2O

e -

h +

LiquidSolid

SrTiO3

KTaO3

TiO2

SnO2

Fe2O3


Optimum Absorption Threshold

0.00

0.04

0.08

0.12

360 760 1160560 960

Wavelength, nm

AM 1.5 Solar Spectrum

Too LargeBand Gap

Too SmallBand Gap

Irra

dia

nce

,mW

/(cm

-nm

)2


Production of Hydrogen by PEC at University of Hawaii


Sources: E. Miller and R. Rocheleau, “PhotoElectrochemicalProduction of Hydrogen”, Proceedings of the 2002 US DOE Hydrogen Program Review

Possible Structure of PEC for Hydrogen Production atUniversity of Hawaii


Sources: E. Miller and R. Rocheleau,“PhotoElectrochemical Production ofHydrogen”, Proceedings of the 2002 US DOE Hydrogen Program Review

Biological Hydrogen Production


Photosynthetic bacterial productionDark fermentation productionMicrobial-aided electrolysis

Hydrogen Production Overview of Technology Options, Freedom Carand Fuel PartnershipFrom:https://www1.eere.energy.gov/hydrogenandfuelcells/pdfs/h2_tech_roadmap.pdf

hydrogen technology (05) - hydrogen properties and … · (iso/tr 15916:2004). the solidified gases...

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