| Spinoff
Technology: #
688 |
High-temperature, solid oxide fuel cell and
co-production systems
Ztek
Corporation (, )
ZTEK Corporation
(Woburn, MA) has developed a stationary, high-temperature,
zirconia-based, solid-oxide fuel cell system. ZTEK was funded by
the missile defense program in 1988 to examine this technology for
its use as a power system for space systems. What sets ZTEK’s
current fuel cell product apart from other stationary,
high-temperature fuel cell systems is that ZTEK has developed a
system that not only generates electricity, but can also produce
hydrogen. The hydrogen co-production system is becoming part of
two projects in California that will be used to refill fuel cell
vehicles with hydrogen. The company has also combined an SOFC with
a turbine to increase the efficiency of generating electricity.
Technology Description:
The core of
ZTEK’s system is a zirconia solid-oxide fuel cell that operates at
900° to 1000°C. Air enters the cathodic compartment, where
electrons from the cathode split the oxygen molecule into oxygen
ions. The oxygen ions travel through the solid-oxide electrolyte
(zirconia) and react with the hydrogen or carbon in the fuel,
forming water and carbon dioxide and releasing electrons. Steam
and carbon dioxide exit the cell as exhaust, and the electrons are
harvested as electricity through external loads.
To
co-produce hydrogen, ZTEK developed a steam reformer that uses the
fuel cell’s waste heat. The reformer and fuel cell are co-located
within a container and in close thermal contact. Most hydrogen
used in the United States is produced through simple steam
reforming. The process uses high temperatures, steam, natural gas,
and a catalyst to promote the reaction of natural gas with water,
which produces hydrogen, carbon monoxide, and carbon dioxide.
Typically, the heat for the reaction and the production of steam
is generated by burning additional natural gas. However, ZTEK uses
the waste heat and steam from the fuel cell reaction to increase
the efficiency of the process and reduce the reformer’s footprint
and size. The fuel cell and reformer fit in a 10 foot
cube.
ZTEK has also developed a solid-oxide fuel cell
integrated with a turbine that is powered by the fuel cell’s high
temperature exhaust. Incorporating the two electrical-generation
methods, the system can generate electricity at between 60 and 80
percent efficiency.
Spinoff Applications:
ZTEK’s fuel cell
technology has several commercial applications. Stationary,
high-temperature fuel cells of various types are currently used to
provide electricity and building heat or air-conditioning for some
industrial customers. ZTEK has demonstrated units in this area,
but the company sees the most potential in building systems to
generate hydrogen.
When hydrogen-powered cars begin to
take to the streets, their drivers will likely pay a premium for
the fuel, and there may be government subsidies available for
companies generating hydrogen for vehicles. Therefore, while fuel
cells cannot yet compete with traditional electric utilities on
the price of electricity, ZTEK’s fuel cells may be competitive or
offer more flexibility to organizations looking for hydrogen
fueling solutions.
ZTEK’s hydrogen-generation system has a
distinct advantage compared with other hydrogen-generation
systems—it can generate and sell electricity when hydrogen fuel
demand is low. In addition, the system is very efficient,
converting 85 percent of the fuel’s available energy into
hydrogen. It also efficiently produces electricity, so that if
upfront costs are not considered—if they were paid for by an
investment in hydrogen—the electricity generated would be
inexpensive and could be sold to local electric utilities.
Commercialization:
ZTEK has several
fuel cell systems in demonstration projects around the country. A
simple-cycle ZTEK fuel cell is currently being demonstrated in
Connecticut, and the waste heat from the fuel cell is being used
to produce heating and cooling through an absorption chiller.
Previous versions of the fuel cell system have been demonstrated
by the Tennessee Valley Authority. The company’s fuel cell and
integrated turbine technology will be demonstrated by AT&T
(formerly SBC) to provide electricity for a phone-network
switching station.
For hydrogen production, a
demonstration hydrogen refueling station is being built in San
Carlos, CA, by ZTEK in partnership with Pacific Gas and Electric.
It is part of the California Fuel Cell Partnership and is expected
to become operational in mid-2006. In January 2006, ZTEK entered
an agreement with U.S. Department of Navy to collaborate on a
hydrogen-fueling project at the U.S. Marine Corps Base Camp
Pendleton near Oceanside, CA. When operational, the station will
serve both military and commercial hydrogen vehicles in the
area.
ZTEK has three models of hydrogen-producing systems,
all of which covert 85 percent of the energy contained in the fuel
into usable hydrogen. When enough hydrogen has been produced the
units can be switched to produce electricity. The HPSR 600H
produces 600 standard cubic feet of hydrogen per hour; the HPSR
4000H produces 4,000 standard cubic feet of hydrogen per hour; and
the HPSR 2000H/75E produces 2,000 standard cubic feet of hydrogen
per hour and 75 kW of electricity.
Company Profile:
ZTEK is privately
held and has been working with zirconia solid-oxide fuel cells for
over 20 years. The company has over 200 patents on its fuel cell
technologies and has successfully defended an invention against an
infringer. The company has announced that it has a commercially
ready fuel cell and hydrogen co-production products, and is
looking for customers and investors.
Contact Information:
Disclaimer: The views
expressed in this article are those of the author and do not
reflect the official policy or position of the Department of
Defense or the U.S. Government.
