Membrane Reactor forHydrogen Production

Ashok DamleJim Acquaviva

Pall CorporationNovember 17, 2008

This presentation does not contain any proprietary or confidential information

AIChE 2008 Annual Meeting, Philadelphia, PA

Photo courtesy of Pall Corporation

2

Contributors & Acknowledgments

• Pall Corporation– Scott Hopkins– Daniel Henkel– Rick Kleiner– Rajinder P. Singh– Hongbin Zhao– Keith Rekczis– Chuck Love– Kevin Stark

• Colorado School of Mines– J. Douglas Way– Oyvind Hatlevik

• RTI International– Carrie Richardson

• DOE (EERE)– Sara Dillich

3

Presentation Outline

• Drivers for Hydrogen Production and CO2 capture

• Process intensification / Membrane reactor concept

• Status of Pd-alloy composite membrane at Pall• Inorganic substrate development

• Composite Pd-alloy membrane development

• Membrane reactor model simulations• WGS Membrane reactor experimental studies

• Pall’s capabilities and future activities

4

Hydrogen Economy and Production

Two major drivers for hydrogen production• Hydrogen as energy carrier – Transportation,

Power/heat generation, and Chemical production

• Pre-combustion CO2 capture and hydrogen production has potential to reduce GHG emissions

Hydrogen Production

• Can be produced from multiple pathways – natural gas, coal, biomass and renewables

• Near term hydrogen production from Natural Gas

• Longer term hydrogen production from Coal and renewable energy sources (biomass, solar, wind)

5

Conventional Hydrogen ProductionExhaust

NaturalGas

Air SyngasGenerator

WGS PSA

HydrogenProduct

800 oC400 oC

WaterResidual Gas

Current State:

> 90 % of H2 is produced from NG by this process

Very efficient on large scale

Future State: Combining hydrogen generation and separation (process intensification) can potentially reduce capital and operating cost of hydrogen production at various scales

6

WGS Membrane Reactor Process

WGS MembraneReactor

800 oC400 oC

HydrogenProduct

Water

Exhaust

NaturalGas

AirSyngas

Generator

Residual Gas

• Increased conversion due to equilibrium shift• Compact system, smaller footprint• Simpler operation and lower operating/energy costs• Need compressor for high pressure hydrogen product

7

Membrane Reformer Process

NaturalGas

Air MembraneReformer

HydrogenProduct

Water

ExhaustCO2

600 oC

Steam

ResidualGas

� Compact unit, smaller footprint � Lower capital cost Milder conditions

� Increased hydrogen yield � Greater energy efficiency, Less steam Lower cost of H2 production

� Need high temperature inorganic membrane for H2 separation

Efficiency improvement through process intensification

8

1. Lee, D., Zhang, L., Oyama, S. T., Niu, S., and R. F. Saraf, J. Membr. Sci., 231, 117(2004).

2. Kajiwara, M., Uemiya, S., Kojima, T., and E. Kikuchi, Catal. Today, 56, 65(2000).

3. DeVos, R. M. and H. Verweij, Science, 279, 1710(1998).

4. Hassan, M. H., J. D. Way, P. M. Thoen, and A. C. Dillon, J. Membr. Sci. , 104, 27(1995).

5. Polymer line from :Robeson, L. M., J. Membr. Sci., 62, 165(1991).

6. Wu, J. C. S. et al., J. Membr. Sci., 77, 85(1993).

7. Hatlevik, Ø., Gade, S. K., Keeling, M. K., Thoen, P. M. and J. D.Way, "Palladium and Palladium Alloy Membranes for Hydrogen Separation and Production: History, Fabrication Strategies, and Current Performance," submitted to Separation and Purification Technology, Sept. 2008.

Why Palladium Membrane ?

1

10

100

1000

104

105

10-9 10-8 10-7 10-6 10-5 0.0001

10-9 10-8 10-7 10-6 10-5 0.0001

Polymeric Membrane MaterialsInorganic Membrane MaterialsH

2/N2

Idea

l Sep

arat

ion

Fac

tor

H2

Permeance (mol/m2.s.Pa)

CSM PdAu

(1)

(2)

(3)

(4)

(6)

CSM Pd

(7)

(7)

Graph courtesy of Prof. Doug Way and CSM group

9

Pd-alloy membrane development

Self supporting membrane structures• Need membrane of sufficient thickness for

structural integrity and strength e.g. tubes or flat sheets > 25 µm

• Expensive, Niche applications – small H2 purifiers

Composite membrane structures• Thin films on substrates• Substrate provides structural integrity and strength • Deposition of thin Pd-alloy films by various

techniques ~ 1 – 5 µm• Better seals for High T – High P applications• Lower cost – thin Pd layer, less membrane area

10

Components of a Composite Membrane3) Pd alloy membrane

– Functional layer provides for gas separation

– Critical features: thickness, alloy composition, durability and number of defects

1) Porous stainless steel– Provides mechanical support that

can withstand the operating conditions of the process

– Critical features: permeability, weld configuration, mechanical, thermal and chemical compatibility

2) Diffusion barrier– Enables formation of functional

layer– Critical features: surface

properties, material, gas permeability, number of defects

Pd-alloy membrane development at Pall

3

2

1

Excellent adhesion to zirconia layer, uniform thickness, and surface contour following of Pd-alloy metal film

11

Ceramic / PSS composite substrate for Pd alloy membranes

PSS Medium

Ceramic Coating

It’s all about the substratePorous stainless steel tube with ZrO2 ceramic coating: Extensive development work done to optimize the composite structure and surface properties to enable formation of a high quality Pd alloy or other functional layer.

Pd-alloy membrane development at Pall

• All welded designNo polymer seals, Higher temp. capabilities

• Thermal expansionUniform thermal expansion with the housing and module components

• CostAll metal design with welded fittings, allows for direct welding to a tube sheet. This eliminates the need for intricate sealing mechanism and reduces overall module cost

12

Durability : Pall Gas/Gas separation supports have been exposed to multiple thermal cycles with no detrimental effects to the composite structure– Ceramic layer stable and maintains adhesion to metallic

substrate through thermal cycles

– Composite tube with 310SC can be used up to 550 oC in pure H2 and up to 400oC in air or inert gases

Characterization Data of Composite Support�First bubble in IPA is > 30 psi

�Air permeability @ 1000 cc/min ~ 7 psi

�Zirconia coating pore structure is 70 nm

�Base metallic tube pore structure is 2 microns in average

Pd-alloy membrane development at Pall

13

���������� ����������

� �� ���������������������

� ����������� ����! �� ���

"�#���$��� �#��� �$

� ���%�$������� �

� &�� �

� �#�����'(

� �������� $�)���15 cm2 active surface area

75 cm2 active surface area

Pd-alloy membrane development at Pall

14

Membrane Durability in Thermal Cycling

Thermal Cycle: Air � Air � Argon � Hydrogen � AirTemperature (C): 25 � 400 � 400 � 400 � 25Pressure (psig): 0 � 20 � 20 � 20 � 0

15

Components of a Gas/Gas Separation Module

Pressure vessel with fittings

Internal hardware

Non-porous end fitting

Porous substrate

Weld

Membrane tube sub-assembly*

* Pd alloy membrane not shown, typically on the OD of the tube

Welds

1616

Membrane Reactor Model Simulations

Model Assumptions

• Temperature and total pressure constant on both sides

• Reaction kinetics faster than hydrogen permeation

• Feed side is in dynamic equilibrium

• Hydrogen flux determined by local driving force

Permeate HydrogenMembrane

Fuel Gaswith Steam Residual Gas

Fuel Reforming/WGS Catalyst

H2 H2

17

WGS Membrane Reactor Experimental Results

Demonstrated > 80% Net Recovery of Hydrogen with >80% CO conversion

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60 70 80 90 100

Net Hydrogen Recovery, %

CO

Con

vers

ion,

%

Methane Reformate Feed Gas (Dry)H2 - 75.2%CO - 15.6%CO2 - 7.1%CH4 - 2.1%

Steam:CO = 1.2:1Temperature - 375 oCFeed Pressure - 100, 150 psigHigh Temp. Fe-Cr WGS Catalyst(Sud-Chemie - Shiftmax 120)

Model Prediction (Fast Kinetics)

Experimental DataEquilibrium CO Conversionat Feed Gas Conditions 100 psig

150 psig

Experiments conducted by Damle at RTI International – Fuel Cell Seminar 2007

18

Predicted Methane Conversion increase@ T – 600 C, Steam:C::2:1, P-100, 250 psig

Effect of Pressure – Greater H2 recovery and yieldin spite of unfavorable equilibrium

19

Membrane Reactor Performance@ T – 600 C, Steam:C::2:1, P-100 psig

Recovery of sensible and combustion heat of Residual Gas Net heat requirement analysis

20

Membrane Reactor Performance@ T – 600 C, Steam:C::2:1, P-250 psig

Effect of Pressure – Greater H2 partial pressureLess Membrane Area requirement

21

Membrane Reactor Performance@ T – 600 C, Steam:C::3:1, P-100 psig

Higher Steam:C ratio – Greater H2 partial pressureLess Membrane Area requirementRelatively small energy penalty

22

Membrane Reactor Performance@ T – 550 C, Steam:C::2:1, P-100 psig

Lower Temperature – Lower H2 partial pressure – less conversion(strong effect) Low hydrogen recovery

23

Components of Economic Analysis

Economic Model

Membrane Reactor Model

Energy Model

H2 Cost($/gge)

Process

Data

ProcessModel

Compression

Cost

Hydrogen Permeate Flow

Surface AreaMembrane Pilot Plant

Performance Measurements

CompressorOPEX & CAPEX

MembraneOPEX & CAPEX

PSAOPEX & CAPEX

NG reformer

24

Potential Benefits of Membrane Reactor

Basis: 100 Kg/day (1650 SCFH)

• Membrane module area ~ 10 ft2

• Membrane Module cost with DOE Target ~ $7,500

Cost of metal ~ $ 235 (October 2008 prices)

• Capital cost reduction by replacing PSA/WGS ~ $ 40,000

• DOE H2A Forecourt Model – Capital cost portion ~ $3.06/kg H2

• Potential reduction in capital cost contribution ~ $0.36/kg H2

• Penalty for 50% additional compressor cost ~ $ 0.08/kg H2

• Additional benefits not yet quantified– Increased hydrogen yield– Reduced operational cost– Reduced energy costs

25

Future R&D Needs – Reduce Cost

Capital Cost• High flux membrane to reduce required membrane area and pressure

vessel size• High efficiency modules to maximize use of membrane area• Commercial scale manufacturing process for Pd alloy membranes• Process integration to reduce balance of plant cost• Process intensification (ex: membrane reactors) to minimize catalyst

and hardware cost

Operating Cost• High separation factor membranes that maximize H2 recovery• Process integration to minimize the energy penalty for CO2 capture

Maintenance Cost• Durable palladium alloys that can tolerate severe process conditions,

abrupt startups & shutdowns, and contaminants in feed streams

26

Research Development

Scale-up of Metal Tube Technology

Commercialization

27

Questions ?