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| Types of Fuel Cells | The Basics | Fuel Cell News | Basics on Hydrogen | Search| |
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Voller Energy Group is pleased
to announce that it has achieved a major milestone in the development of
its fuel cell auxiliary power units (APU) by successfully integrating a
complete fuel processor and fuel cell system ahead of schedule. As a result
of these developments, the Company has demonstrated the conversion of input
hydrocarbon fuels into useable electrical power within a self contained
system.
The system demonstrates quiet operation, very low emissions and high efficiency. Furthermore, the fuel cell APU system has the advantage of working from widely available fuels such as Calor Gas, propane or liquefied petroleum gas (LPG). Other fuel cell systems require pure hydrogen, which is not yet commonly available. The Company believes that these attributes make the units highly attractive for commercial applications in our target markets of leisure, construction and military.
In these markets standard diesel generators are commonly used. These generators are both noisy and emit high levels of emissions. Initial indications are that the emissions from the fuel cell APU will be approximately 60x lower than comparable generators. In particular, the fuel cell would have to run for about 200 years to produce the same sulfur (sulphur) emissions or smells as the generator would typically produce in a day. In addition, the carbon dioxide emissions from the fuel cell APU to recharge the batteries would be just 5kg. This is about the same amount of carbon dioxide as a normal person breathes out in a week.
These developments meet the 2006 Q4 milestone described in April 2006, and the Company remains on target to deliver commercially available 1kW fuel cell APU systems by the end of 2007.
This excellent achievement is a result of the extensive expertise which Voller has developed in the design and integration of fuel cell systems. The development has significantly enhanced the Company’s intellectual property and know-how.
Stephen Voller, Chief Executive said:
“We are delighted to make this announcement demonstrating that the technology programme we highlighted earlier this year is on track to be able to provide the market with a 1kW fuel cell APU by the end of 2007. Voller is the only organisation that has successfully integrated these technologies into a commercially viable product. This reaffirms the strengths of our in-house know how and the capability of our development team. In the light of this encouraging news we are exploring new commercial opportunities which may have a significantly positive impact on the economic prospects of the Group.”
Target Markets
An early target market for the APU is sailing yachts in the 40-49ft class. According to the International Boat Industry (IBI) there were 4,621 new yachts commissioned in this class in 2005. These yachts typically use 4 x 100Ah (Amp Hour) batteries and typically require around 2,000-8,000 watt-hours during a 24-hour period. Some yacht owners run their engine, so that the alternator can provide this charge. Running the engine for electrical power is inefficient, noisy, undesirable and not good for the engine itself. An alternative solution is to use a marine diesel generator. Used in support of an air conditioning system the generator will also provide power for battery recharging.
The fuel cell APU solution brings significant advantages over the traditional diesel generator. Not least, the APU is quiet in operation and does not vibrate, which can be intrusive, especially in an enclosed sailboat cabin. A diesel generator is heavy especially when mounted on a 100kg anti- vibration base plate. Typically a generator installation together with the anti-vibration plate weighs about 250kg. The APU system is targeted to weigh considerably less than this. This weight saving is extremely important to a sailboat owner. A diesel generator requires ongoing servicing and maintenance much as a car engine does. Typically this may mean an oil change after 150 hours of use, and an oil filter change about every 300 hours of use. Initial estimates are that the APU will be maintenance free for 1,000 hours of use and then will require just a sulfur trap filter change.
In terms of functionality the generator purely brings power whilst the APU provides power, hot water and also space heating. This is relevant to the yachtsman used to spending extra money on standalone heating systems.
An emissions comparison was conducted with a standard diesel generator. Initial indications are that the noxious emissions from the fuel cell APU will be approximately 60x lower than the generators.
The design of the system is to work with commercial grade LPG. LPG contains sulfur that if passed into the reformer and fuel cell directly would significantly degrade the performance. Sulfur compounds in the form of mercaptans are added to LPG so that the gas can be easily smelt. The chemists at Voller have developed both sulfur removal and methanation reactor (CO removal) systems as part of the APU development. This has involved the use a low cost catalyst that successfully removes the sulfur to almost immeasurable levels and CO to less than 5 ppm.
Fuel cell APU technology
The fuel cell APU consists of a number of complex inter-dependent sub-systems that are integrated together into a seamless product. The design goal is that the user attaches their LPG canister and clean, quiet power is produced. Under normal operation the end-user does not have to be aware of the complexities inside the system.
The system that Voller Energy has developed uses an allothermal steam reforming process and a number of gas purification stages to convert the input propane or LPG into hydrogen, which is then directly fed into the fuel cell sub-system. The major sub-systems consist of:
Sulfur removal
* Steam reformer
* Water-gas shift
* Methanation
* Power conditioning
* Battery charging
and management
* Cell voltage
monitoring
* Fuel cell stack
control
* Water recovery
and purification
* Flow control
systems
In allothermal steam reforming, the propane fuel is reacted with water vapour at elevated temperatures and pressures over a catalyst to form a mixture of hydrogen and carbon monoxide (often referred as “syn-gas”). A typical composition would be 70% hydrogen and 30% carbon monoxide. This process is followed by a further process (the “water gas shift reaction”) which converts the carbon monoxide to carbon dioxide, extracting further hydrogen from the steam. Finally, virtually all of the traces of carbon monoxide, which would poison the fuel cell, are removed in a “methanation” process, which involves reacting the carbon monoxide with hydrogen to form methane over a final catalyst bed. Carbon monoxide concentrations following this process are at the low single digit ppm level. Carbon monoxide concentrations of less than 10 ppm are necessary for effective performance of the fuel cell module.
Precise control of the temperature and pressure in each of these stages is essential for optimal performance and the production of gas of the required purity. Furthermore, since the catalysts used are sensitive to sulfur containing compounds, an initial sulfur clean-up stage is also required prior to the allothermal reforming process.
Sulfur removal can be achieved via reaction with a suitable absorbent material. Voller has evaluated commercial sulfur absorption materials and verified that these materials will remove virtually all of the sulfur containing species (residual about 0.5 ppm) over the desired lifetime of the system. Importantly these work with commercially available LPG fuels as in addition to poisoning the catalysts, sulfur compounds cause many of the characteristic smells produced by conventional generators. As a result, the fuel cell APU will be free of these odours.
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