Post on 09-Dec-2015
description
Fuel Cell
What is fuel cell?
A fuel cell is a device that generates
electricity by a chemical reaction.
History: 1801: Humphry Davy demonstrates the principle of
what becomes the fuel cell
1839: William Grove invents the gas battery, the first fuel cell
1889: Charles Langer and Ludwig Mond develop
Grove’s invention and name it fuel cell.
1950: General Electric invents the proton exchange membrane fuel cell.
1959: Francis Bacon demonstrates a 5kW alkaline fuel cell.
1960: NASA first uses fuel cell in space
mission.
1970: The oil crisis prompts the development
of alternative energy technologies including
PAFC
1980s: US Navy uses fuel cells in submarines.
1990s: Large stationary fuel cells are
developed for commercial and industrial
location.
2007: Fuel cell begin to be sold commercially
as APU and for stationary backup power.
2008: Honda begins leasing the FCX clarity
fuel cell electric vehicle.
History:
Harnessing Hydrogen Steam reforming is a method for producing hydrogen,
carbon monoxide, or other useful products from
hydrocarbon fuels such as natural gas. This is achieved in
a processing device called a reformer which
reacts steam at high temperature with the fossil fuel.
CH4 + H2O ⇌ CO + 3 H2
CO + H2O ⇌ CO2 + H2
Harnessing Hydrogen In chemistry and manufacturing, electrolysis is a
technique that uses a direct electric current (DC) to
drive an otherwise non-spontaneous chemical
reaction. Electrolysis is commercially highly important as
a stage in the separation of elements from naturally
occurring sources such as ores using an electrolytic cell.
Collecting hydrogen generated as a waste product by
some strains of algae and bacteria.
2 NaCl + 2 H2O → 2 NaOH + H2 + Cl2
2 H2O(l) → 2 H2(g) + O2(g)
Proton Exchange Membrane
Efficiency is about
40% to 50%, and
operating
temperature is
about 80˚C. Uses
Hydrogen and
Oxygen to produce
electricity
Direct-methanol Fuel CellsSubcategory of proton-
exchange fuel cells in
which methanol is used as
the fuel. Their main
advantage is the ease of
transport of methanol, an
energy-dense yet
reasonably stable liquid at
all environmental
conditions.
Alkali Fuel CellAlkali fuel cells operate on
compressed hydrogen and oxygen.
They generally use a solution of
potassium hydroxide in water as their
electrolyte. Efficiency is about 70 %,
and operating temperature is 150 ˚C
to 200 ˚C. Alkali cells were used in
Apollo spacecraft to provide both
electricity and drinking water. They
require pure hydrogen fuel, however,
and their platinum electrode catalysts
are expensive. And like any container
filled with liquid, they can leak.
Molten Carbonate Fuel CellsUses high-temperature
compounds of salt carbonates
as the electrolyte. Efficiency
ranges from 60% to 80%, and
operating temperature is
about 650 ˚C. Their nickel
electrode-catalysts are
inexpensive compared to the
platinum used in other cells. But
the high temperature also limits
the materials and safe uses of
MCFCs–they would probably
be too hot for home use.
Phosphoric Acid Fuel CellsUses phosphoric acid as the
electrolyte. Efficiency ranges from
40-80%, and operating
temperature is between 150 ˚C to
200 ˚C. PAFCs tolerate a carbon
monoxide concentration of about
1.5%, which broadens the choice
of fuels they can use. If gasoline is
used, the sulfur must be removed.
Platinum electrode-catalysts are
needed, and internal parts must
be able to withstand the corrosive
acid.
Solid Oxide Fuel CellsUses a hard, ceramic compound of
metal oxide as electrolyte. Efficiency
is about 60%, and operating
temperatures are about 1,000 ˚C. At
such high temperatures a reformer is
not required to extract hydrogen
from the fuel, and waste heat can
be recycled to make additional
electricity. However, the high
temperature limits applications of
SOFC units and they tend to be
rather large. While solid electrolytes
cannot leak, they can crack.
DISADVANTAGES Efficiency - Fuel cells are generally more
efficient than combustion
Simplicity - Fuel cells are essentially simple
with few or no moving parts. High reliability
may be attained with operational lifetimes
exceeding 40,000 hours.
Low emissions - Fuel cells running on direct
hydrogen and air produce only water as
the byproduct.
Silence - The operation of fuel cell systems
are very quiet with only a few moving parts
if any.
Flexibility - Modular installations can be
used to match the load and increase
reliability of the system.
Cost - The principal
disadvantages of fuel
cells, however, are
the relatively high cost
of the fuel cell, and to
a lesser extent the
source of fuel.
ADVANTAGES
Application Combined Heat and Power Systems
The primary stationary application of fuel cell technology is for the combined
generation of electricity and heat, for buildings, industrial facilities or stand-by
generators. Because the efficiency of fuel cell power systems is nearly unaffected by
size, the initial stationary plant development has focused on the smaller, several
hundred kW to low MW capacity plants. “The plants are fuelled primarily with natural
gas, and operation of complete, self-contained, stationary plants has been
demonstrated using PEMFC, AFC, PAFC, MCFC, SOFC technology”
Portable Electronic Equipment
fuel cells could replace batteries that power consumer electronic products such
as cellular telephones, portable computers, and video cameras. Unlike transportation
applications where fuel cells are competing with the internal combustion engines to
indirectly produce a mechanical output, in portable electronic equipment fuel cells
are in competition with devices such as batteries to produce an electrical output. As
a result fuel cells can offer a viable alternative to batteries and several low power
fuel cells are currently being manufactured for this application.
fin
LIST OF COMPANIES
BallardPowerSystems - Burnaby, Canada
FuelCellEnergy - Danbury, Connecticut, United States
Hydrogenics Corporation - Mississauga, Canada
PlugPower - Latham, New York, United States
HyperSolar - Santa Barbara, CA
Ceres Power - United Kingdom
Ceramic Fuel Cells - Noble Park, Australia
Proton Power Systems - Wallingford, Connecticut, US
AFC Energy - Surrey, United Kingdom
ITMPowerPLC - Sheffield, United Kingdom