Solid Oxide Fuel Cells and Applications to Ecological System Engineering

Dr. Sepideh Faraji

Chemical Engineering DepartmentCSULB

December 2011

Opening questionsWhat is air pollution?

Wh t th ff t f i ll ti b d ?What are the effects of air pollution on our body?

Is there any air pollution in California?

Background

Air pollution is a major problem in California.

Air pollutants are the by-products of the combustion of

fossil fuels:fossil fuels:

- Toxic gases such as CO

- Greenhouse gases such as CO2

O t d i ll tiOne way to reduce air pollution:

- using alternative energy (fuel cells)

What is fuel cell?• Fuel cell is a device that converts the chemical energy

from a fuel into electrical energy.

• The following reaction takes place in a fuel cell:

H2 + 0.5 O2 H2O + heat

• Fuel cells are different from batteries!batteries!

Picture from Wikipedia

Fuel cell applications

Fuel cell applications

Picture from http://www.iepm.com/business_oppty.htm

Different types of fuel cells

Electron ElectronElectron Electron

ElectrolyteA dC th d

ElectrolyteA dC th dAnode

H2

Cathode

O2

Anode

H2

Cathode

O2Oxygen Hydrogen

Water

Solid Oxide Fuel Cell (SOFC) Proton Exchange Membrane (PEM) f l llfuel cell

SOFC

• Advantages: ElectronElectron

• High efficiency

• Cheap ElectrolyteA dC th d

• Fuel flexibility

• Disadvantages:

Anode

H2

Cathode

O2 Oxygen• Disadvantages:

• High temperatures Water

• Slow startup time

SOFC

Where does hydrogen come from?

H d k

ElectronElectron

• Hydrogen tank

• Other hydrocarbons: ElectrolyteA dC th d

- methanol, natural gas, …Anode

H2

Cathode

O2 Oxygen

How to produce hydrogen from other

h d b ?Water

hydrocarbons?

• Reaction in anode:

CH4 + O2 CO2 + 2H2

SOFC challengesAnode reaction: ElectronElectron

ElectrolyteA dC th d

hydrocarbon + O2 CO2 + H2

A perfect catalyst for this reaction

has not been found yet:

Anode

H2

Cathode

O2 Oxygeny

• Cost of catalyst

O ti t t f t l t• Operating temperature of catalyst

• Catalyst lifetime Water

Research objectives• Investigate different catalysts for hydrogen

production:production:

1 Pt based catalysts1. Pt-based catalysts

2. Ni-based catalysts

• Investigate the lifetime of the catalysts• Investigate the lifetime of the catalysts

Experimental• Ni/CeZrO2 and Ni/Al2O3 catalyst preparation:

• Incipient wetness impregnation method (15 wt% Ni)p p g ( )

• Catalysts were not reduced

• Pt-Ni/CeZrO2 and Pt-Ni/Al2O3 catalyst preparation:

• Incipient wetness impregnation method (0.2 wt% Pt and 15 wt% Ni)

• Catalysts were not reduced

Experimental

Reduction of new catalysts(Heating up the catalyst in H2)( g p y 2)

Pt-Ni is active at lower temperatures.

New catalysts(Heating up the catalyst in CH4+CO2)( g p y 4 2)

Pt-Ni is active at lower temperatures.

The effect of catalyst on reaction at 800°C

P Ni/Al O l i bl• Pt-Ni/Al2O3 catalyst is very stable.

• Pt-Ni/Al2O3 catalyst shows highest conversion and H2/CO ratio.

The effect of temperature on reaction

• Operating temperature affects methaneOperating temperature affects methane conversion and H2/CO ratio.

• Pt Ni/CeZrO catalyst shows highest conversion• Pt-Ni/CeZrO2 catalyst shows highest conversion and H2/CO ratio at 600 °C.

Conclusions• Pt-Ni/CeZrO2 catalyst shows a very promising

performance at 600 °C.performance at 600 C.

• Pt increases the reducibility of Ni particles in the bimetallic catalystbimetallic catalyst.

Future Direction• New catalyst support with high surface area.

• Hydrogen production from renewable resources:• Hydrogen production from renewable resources:- Ethanol reforming at low T.

Waste glycerol reforming at low T- Waste glycerol reforming at low T.

AcknowledgementsAcknowledgements• California State University, Long Beach

•University of Kansas

• MEL chemicals

Q i ?Questions ?