Hydrogen liquid fuel storage

Liquid Fuel Storage The use of a nonhydrogen liquid fuel, such as methanol, as a hydrogen carrier is a common approach to reduce fuel storage volume in portable applications using PEFCs, as discussed in Chapter 6. For these applications, the reduced performance of the fuel cell when using the alternative fuel is acceptable because of the reduced overall system complexity and size. 

Hydrogen onboard storage systems for vehicles are bulkier, heavier, and costlier than those for liquid fuels or compressed natural gas, but are less bulky and less hca than presently envisaged electric batteries. Even with these constraints, it appears that hydrogen could be stored at acceptable cost, weight, and volume for vehicle applications. This is true because hydrogen can be used so efficiently that relatively little fuel is needed onboard to travel a long distance. 

A hydrogen fuel cell is environmentally friendly, but H2 is much more difficult to store than liquid fuels. The production, distribution, and storage of hydrogen present major difficulties, so researchers are working on fuel cells that use liquid hydrocarbon fuels. One such fuel cell is composed of layers of yttria-stabilized zirconia (YSZ), which is solid Zr02 containing around 5% Y2 O3. This cell uses the combustion of a... 

Dehydrogenation activities, compared for tetralin and decalin [5,12] under the same superheated liquid-film conditions over the same Pt/C catalyst, exhibited around 3.9-63 times preference of tetralin (Table 13.3), which can certainly be ascribed to advantageous adsorption due to the a-bonding capability of its aromatic part [17-19]. It was, thus, confirmed experimentally that tetralin is superior to decalin as the organic hydrogen carrier for stationary applications in terms of rapid hydrogen supply or power density, provided that the density of fuel storage is unimportant. 

If fuel cell cars run on gasoline, there is minimum disruption, but many predict that methanol will serve as a bridge to direct hydrogen. Early fuel cell cars may run on methanol, but rapid advances in direct-hydrogen storage and production could bypass any liquid fuel phase. 

In a liquid hydrogen fuel storage tank the gaseous hydrogen vaporizes and fills the empty volume inside the tanks. This hydrogen is not combustible since there is no oxygen present. In gasoline or other hydrocarbon fuel tanks, air fills the empty volume of the tanks and combines with vapors from the fuel to produce a combustible mixture. 

One major advantage of DME use is that it can be stored as a high-density liquid phase at modest pressures (around 5 atm) and delivered as a gas-phase fuel in a pumpless operation. Therefore, the use of DME can potentially combine the advantages of easy fuel delivery of pressurized hydrogen and the high energy density storage of liquid fuel. In addition, DME is less toxic than methanol. 

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