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Technology Stocks : Energy Conversion Devices -- Ignore unavailable to you. Want to Upgrade?

To: Allen Bucholski who wrote (7076)	1/15/2003 8:15:14 PM
From: Krowbar	Respond to of 8393

Allen, I don't see where Accumetrics would be competition for our H2 storage. They are making a stationary fuel cell that runs directly off of natural gas. Del

To: Allen Bucholski who wrote (7076)	1/15/2003 10:39:07 PM
From: Krowbar	Read Replies (1) \| Respond to of 8393

EV World covers the transport of hydrogen and other fuels by compression and liquefaction in recent articles. I have selected certain parts of interest. By Baldur Eliasson and Ulf Bossel (part 2) "...Numbers provided by a leading manufacturer [5a] of hydrogen compressors show that the energy invested in the compression of hydrogen is about 7.2% of its higher heating value (HHV). This number relates to a 5-stage compression of 1,000 kg of hydrogen per hour from 1 to 200 bar (2900 P.S.I.). For a final pressure of 800 bar (11,603 P.S.I.)10% would perhaps be a realistic value. The analysis does not include losses in the electric motor..... evworld.com ....For small liquefaction plants the energy needed to liquefy hydrogen may exceed the HHV of the gas. But even with the largest plants (10,000 kg/h) about 30% of the HHV energy is needed for the liquefaction process.... Energy Needed to Store Hydrogen in Hydrides At this time only a generalized assessment can be presented for the physical (e.g. adsorption on metal hydrides) or chemical (e.g. formation of alkali metal hydrides) storage of hydrogen. There are many options for both types of hydrogen storage. This makes it difficult to present numbers. But a few cautious statements may be allowed. The laws of nature certainly apply to this type of hydrogen storage as well. In the chemical case, a substantial amount of energy is needed to combine hydrogen with alkali metals. This energy is released when the hydrogen is liberated from the compound. The generated heat has to be removed by cooling and is normally lost. For the physical hydride storage, the hydrogen gas must be pressurized. The energy required for compression has been assessed before. The compression energy is released as heat during the charging process. Also, external heating is needed to liberate the hydrogen from the hydride storage material. According to Ref. [11], p. 264 metal hydrides store only around 55-60 kg(H2)/m 3 compared to 71 kg(H2)/m 3 for liquid hydrogen. But 100 kg of hydrogen are contained in one cubic meter of methanol. Hydride storage of hydrogen is by no means a low-energy process, but it may be compared to the compression of hydrogen. Generalized numbers cannot be presented today. evworld.com Part 3 "......the hydrogen and methane pressure tanks can be emptied only from 200 (2900 P.S.I.) bar to about 42 bar (609 P.S.I.)to accommodate for the 40 bar pressure systems of the receiver. Such pressure cascades are standard praxis today. Otherwise compressors must be used to completely empty the content of the delivery tank into a higher-pressure storage vessel. This would not only make the gas transfer more difficult, but also require additional compression energy. Therefore, pressurized gas carriers deliver only 80% of their freight, while 20% of the load remains in the tanks and is returned to the gas plant. Each 40-ton truck is designed to carry a maximum of fuel. For methanol and octane the tare load it is about 25 tons, for propane about 20 tons because of some degree of pressurization. At 200-bar pressure a 40-ton truck can deliver about 3.2 tons of methane, but only 320 kg of Hydrogen. This is a direct consequence of the low density of hydrogen, as well as the weight of the pressure vessels and safety armatures. In anticipation of technical developments, the analysis was performed for 500 kg of hydrogen, of which 80% or 400 kg are delivered to the consumer. With this assumption, 39.6 tons of dead weight have to be moved on the road to deliver 400 kg (882 lbs.) of hydrogen." A mid-size filling station on any frequented freeway easily sells 25 tons of fuel each day. This fuel can be delivered by one 40-ton gasoline truck. But it would need 21 hydrogen trucks to deliver the same amount of energy to the station, i.e. to provide fuel for the same number of cars per day. Efficient fuel cell vehicles would change this number somewhat, but not considerably. The transfer of pressurized hydrogen from the truck to the filling station takes much more time than draining gasoline form the tanker into an underground storage tank. The filling station may have to close operations during some hours per day for safety reasons. evworld.com Today about one in 100 trucks is a gasoline or diesel tanker. For hydrogen distributed by road one may see 120 trucks on the road, 21 or 17% of them transport hydrogen. One out of six accidents involving trucks would involve a hydrogen truck. This scenario is unacceptable for political and social reasons. While the energy consumption for methane (representing natural gas) appears reasonable, the energy needed to move hydrogen through pipelines makes this type of hydrogen distributions difficult. Not 0.3% but almost 1.4% of the hydrogen flow is consumed every 150 km to energize the compressors. Only 60 to 70% of the hydrogen fed into a pipeline in Northern Africa would actually arrive in Europe. evworld.com Well, the authors don't seem to know about ECD's 7% hydride, which do not need pressurization to fill (but need the heat removed). My calculations of a truck similar to one carrying octane (gasoline) show that 22 tons of HT hydride will carry about 1.5 tons of hydrogen. If it is stored in a hydride tank at the station, all of the heat from filling the tank at the station is used to drive off the hydrogen from the tanker truck. Virtually 100% would be transferred. Likewise, when a car's hydride tank is filled, the heat would be used to drive off the hydrogen from the stations's tank. This is the basis for Stan's patents, and IMO the only way to make the transport of hydrogen in trucks practical. Del