Hydrogen Delivery Liquefaction & Compression

Raymond Drnevich

Praxair - Tonawanda, NY

Strategic Initiatives for Hydrogen Delivery Workshop - May 7, 2003 Agenda

¾ Introduction to

¾ Hydrogen Liquefaction

¾ Hydrogen Compression

2 Praxair at a Glance

¾ The largest company in North and South America

¾ Only U.S. Hydrogen Supplier in All Sizes (Cylinders to Liquid to Pipelines)

¾ Operations in 40 countries

¾ Over 23,000 employees

¾ 3,000 active patents

¾ One million customers worldwide

3 Merchant Hydrogen Plants

Praxair Liquid Hydrogen Plant Praxair Tube Trailer Hydrogen Plant Praxair HGS Plant Praxair Cylinder Hydrogen Plant

4 Gulf Coast Pipeline System

LOUISIANA BATON ROUGE

LAKE CHARLES TEXAS SULPHUR GEISMAR

HOUSTON NEDERLAND BEAUMONT CHANNELVIEW NEW MONT PORT ORLEANS BELVIEU ARTHUR SABINE LAKE BAYTOWN PASADENA DEER LAPORTE PARK GALVESTON BAYPORT BAY TEXAS CITY GULF OF GALVESTON MEXICO HYDROGEN NITROGEN OXYGEN AIR SEPARATION 245 miles of pipeline serving IPLNDUSTRIANTS AL AREA 50 major customers

5 Hydrogen Liquefaction

¾ There are 10 hydrogen liquefaction plants in North America

z Train size ranges from 6 to 35 TPD (5,400 to 32,000 kg/day) North American Liquid Hydrogen Capacity (TPD)

300

250

200

150

100

50

0 1965 1970 1975 1980 1985 1990 1992 1995 1997 Year Air Products Praxair BOC

¾ In the 1960’s, liquid hydrogen plants were built to support the Apollo program. Today, liquid hydrogen is used to reduce the cost of hydrogen distribution.

z Delivering a full tube trailer of hydrogen to a customer results in a delivery of less than 300 kg

z A modern liquid hydrogen trailer carries 4000 kg of liquid hydrogen

6 Hydrogen Liquefaction

H2 Source H2 Purification H2 Liquefaction

SMR PSA Byproduct Cryogenic Cryogenic Gasification Membrane (-423ºF) Renewable

7 Hydrogen Liquefaction

¾ The plants are very capital intensive

z Praxair has started capacity expansions approximately once every 5 years since 1980. The infrequent builds means it’s very difficult to reproduce designs.

z While larger plants are more capital efficient, it’s hard to take the capital risk of building the plant too large.

¾ The process is very energy intensive

z Typical unit powers are on the order of 12.5 to 15 kWhe/kg

100% ¾ The cost stack looks like: 75%

50%

25%

0% Share Capital Power O&M

8 Hydrogen Liquefaction Process Review

H2 Flash Compressor H2 Recycle Compressor To Feed GN2 to N2 Liquefier

External Refrigeration

LN2 Add.

To Storage/Fill

9 Forms of Liquid Hydrogen

Ortho Para

- H+ - H+ - H+ H+ -

¾ Normal Hydrogen is 75% Ortho, 25% Para

¾ Liquid Hydrogen is 0.2% Ortho, 99.8% Para

¾ Heat of Conversion from Normal to Para is 0.146 kWhth/kg

¾ Heat of Liquefaction is 0.123 kWhth/kg ¾ Conversion can cause Vaporization

10 Hydrogen Liquefaction Issues for Consideration

¾ Methods to decrease capital cost:

z Larger scale plants (850 tpd)

z Plant repeatability

¾ Methods to decrease energy requirement:

z New compression and expansion technology „ High speed centrifugal compressors and possibly expanders „ Materials development required

¾ Something completely different?

z New approaches to low temperature refrigeration „ Magnetic refrigerators „ Acoustic refrigerators

11 Challenges:

¾ More cost effective LH2 production systems

z System modularization for traditional sized units

z Larger scale equipment

z Higher efficiency compressors and expanders

z More efficient refrigeration

z Lower cost high-efficiency insulation

¾ Cost effective small scale hydrogen generation

z Low cost high pressure compressors and expanders

z Novel low-temperature refrigeration

z Low heat leak liquid storage units

12 Hydrogen Compression

H2 Production H2 Purification H2 Compression

SMR PSA Small Byproduct Cryogenic Gasification Membrane Renewable Large

13 Hydrogen Compression

¾ Hydrogen is difficult to compress

z Very small molecule

z Positive displacement compressors are used

¾ Hydrogen compressors are expensive

z Materials

z Size

z Redundancy required for reliability

¾ The process is energy intensive

z Typical unit powers are: Inlet-Outlet(psig) Adiabatic Efficiency Compression Energy

300 - 1,000 70-80% 0.6 - 0.7 kWhe/kg

100 - 7,000 50-70% 2.6 - 3.6 kWhe/kg

14 Issues Unique to Hydrogen Compression

¾ Compressor Seal and Clearance Tolerance

z Hydrogen is the lightest of all the gases and has lower viscosity than NG. Hence, it is easier to migrate through small spaces

z Special seals and/or tolerance standards need to be established to achieve high pressures

¾ Hydrogen Embrittlement of Metals

z At elevated pressure and temperature, hydrogen can permeate carbon steel resulting in decarburization

z Conventional Mild Steel has been used in and since 1938 as pipeline material.

z Alloy steels containing Chromium and Molybdenum have been suggested for compressor materials.

15 Hydrogen Compression for Large Scale Pipeline Delivery (Present)

¾ State of the Art

z Multi-Stage Reciprocating Machines - typical to install redundant units in order to keep on-line time between 98-99%.

z 700 - 1000 psig delivery pressures

z Adiabatic efficiencies of 78-80%

z High maintenance costs due to wearing components (e.g. valves, rider bands, piston rings)

¾ Typical Manufacturers

z Dresser-Rand

z Sulzer Burckhardt

z Ariel

z Neuman-Esser

16 Hydrogen Compression for Small Scale Fueling Stations (Present)

¾ State of the Art z V-Belt driven multi-stage reciprocating z Hydraulically driven multi-stage reciprocating z V-Belt driven diaphragm z 5,000 - 10,000 psig delivery pressures

¾ Typical Manufacturers z Neuman-Esser z Fluitron z PDC z Greenfield z Rix z Hydro-Pac z CompAir

17 Hydrogen Compression for Small Scale Fueling Stations (Present)

Compressor Cost Comparison (6000 psig)

$120,000

$100,000

$80,000

$60,000

$40,000

$20,000

$0 Type A - 1 Type B - 1 Type C - 1 Type C - 100

18 Hydrogen Compression Issues for Consideration

¾ Issue of numbers - what happens if we build 100 times the units we build today:

z Cost impact on current technology

z Potential for new technology

¾ Reliability improvements

¾ Maintenance cost reduction

¾ Methods to decrease energy requirement:

z New mechanical concepts

z Non-traditional approaches to compression

19 Hydrogen Compression (Future)

¾ Newer Approaches

z Mechanical „ Guided Rotor Compressor (GRC) „ Linear Compressor

z Non-Traditional „ Electrically Driven Membranes „ Hydride Compressors

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