Fuel Cell Design

ENCH 340

Spring, 2005

UTC

Technical and EconomicAspects of a 25 kW Fuel Cell

Chris Boudreaux

Jim Henry, P.E.

Wayne Johnson

Nick Reinhardt

Technical and EconomicAspects of a 25 kW Fuel Cell

Investigate the design of

--a 25 kW Fuel Cell

--Coproduce Hydrogen

--Grid parallel

--Solid Oxide Electrolyte

• Chemical and Thermodynamic Aspects

Our Capabilities

Outline

• Introduction to the project

• Flowsheet Development

• Equipment Design

• Economics

Introduction

Overall Reaction

Methane + Air --> Electricity

+ Hydrogen

+ Heat

Introduction

Pressure SwingAbsorption

Fuel Cell

Reformer

Gas

Hydrogen

Electricity

Air

Heat

SynGas

POC

Fuel Cell-ChemistrySynGas

Air

O+ O+

H2 H2O CO CO2

POC

O2 N2

“Air”Solid Oxide Electrolyte

Is porous to O+

H2 + CO

Fuel Cell-ElectricitySynGas

Air

O+ O+

H2 H2O CO CO2

POC

O2 N2

“Air”

Electrons

Load

Fuel Cell-ChallengesSynGas

Air

O+ O+

H2 H2O CO CO2

POC

O2 N2

“Air”

H2 + COHot SynGas

Hot Air

Recover H2

Recover Heat

Flowsheet Development

Equipment Design

Economics

Fuel CellHeat. Objective Develop and demonstrate a 25 kW, grid parallel, solid oxide fuel cell system that coproduces

hydrogen. , the installation be configured to simultaneously and efficiently produce hydrogen from a commercial natural gas feedstream in addition to electricity. This ability to produce both hydrogen and electricity at the point of use provides an early and economical pathway to hydrogen production.

. Ceramic processing and challenges in the design and manufacturing process of SOFCs will be addressed

. The amount of hydrogen that the unit produces may be controlled by the adjusting the natural gas flow at steady power production (i.e., adjusting the fuel utilization). A nominal production rate of 25 kg of hydrogen per day falls within the expected upper and lower utilization limits for 25 kW electricity production. The system produces a hydrogen-rich exhaust stream that will be purified using a Pressure Swing Absorption (PSA) unit. The hydrogen flow and purity are interdependent. It is expected that purity >98% is achievable for flows of 2-3 kg/day. Critical impurities, such as CO and CO2 will be measured.

It is not clear that this size system makes sense for commercial production. We are looking at a 25 kW module as a building block for commercial production to begin in 2006.

The size of the 25 kW module is estimated to be smaller than a 5 ft cube. The cost of early commercial systems is expected to be <$10K/kW