Russian scientists develop fullerene-based hydrogen sorbing agent that meets DOE criteria
Scientists from Saint Petersburg have tested various materials for their ability to absorb hydrogen and found that a composite material consisting of fullerene-containing soot and magnesium hydride meets the targets set out by the U.S. Department of Energy (DOE) for hydrogen transport power systems. Given that hydrogen is likely to be made from biomass in the future, the latest developments in storage technologies are important for the bioenergy community.
The DOE has fixed two targets for hydrogen storage solutions applied to automotive transportation. The first target requires a ratio of hydrogen weight / tank weight that is superior to 0,065 (6,5% weight). This target limits the weight of the tank. The second target requires a hydrogen volumetric density higher than 62 kg/m in order to limit the volume of the tank.
The Russian researchers from the Ceramic Thermal Materials Science and Engineering Centre focused their work on building an experimental hydrogen storage material with a gas weight content of around 60 kilogram and a volume content not less than 5% per cubic meter. Current traditional methods of storing nitrogen, either under high pressure in gaseous condition, or in liquid or adsorbed state, have low hydrogen parameters, both in weight and volume.
To develop their storage method, the scientists looked at various solid sorbents, based on carbon nanostructures - multi-layer nanotubes, astralenes (nanodispersible fulleroid systems) and fullerene-containing soot - which are activery studied around the world. They also analysed specialy treated palladium, magnesium hydride and their composites.
The researchers performed their tests at a special hydrogen test stand able to operate under temperatures from -180 to +800 degrees centigrade and with pressures varying from 0.0001 millimeter mercury column to 20 megapascals, as well as under various environmental conditions.
The scientists found that the inner cavities of all materials (central channels and interlamellar zones of nanotubes and astralenes) do not absorb hydrogen despite any type of specialized preliminary treatment for these materials. Enthusiastic researchers have tested palladium as a catalytic agent, but failed: this metal added only 1-1.5% to hydrogen absorption. Other nanomaterials - graphite fiber, activated carbon, pure fulleren dust, titanium powder and titanium metal hydride - showed much lower sorption values than powders of nanostructural materials.
Fullerene-containing soot appeared to be the winner among sorbent materials:
energy :: sustainability :: biomass :: bioenergy :: biofuels :: biohydrogen :: storage :: materials sciences :: fullerenes :: nanotechnology ::
The researchers prepared a powder of fullerene-containing soot, treated it with glycerol, and added magnesium hydride powder. These manipulations resulted in a sorbing agent the hydrogen sorbing parameters of which fit the requirements for hydrogen storages developed by the U.S. Department of Energy (DOE).
The new sorbent boasts the following parameters: the weight content of hydrogen slightly exceeds 5%, which leads to 65 kg in one cubic meter. Maximum absorption is shown under conditions of 200-350 degrees centigrade and 1-10 megapascals. The reverse process is highly effective at temperatures of 340-350 degrees centigrade.
Image: fullerenes are a family of carbon allotropes - molecules composed entirely of carbon, in the form of a hollow sphere, ellipsoid, or tube.
References:
Russian Information Center: New Horizons of Storing Hydrogen - August 30, 2007.
Article continues
The DOE has fixed two targets for hydrogen storage solutions applied to automotive transportation. The first target requires a ratio of hydrogen weight / tank weight that is superior to 0,065 (6,5% weight). This target limits the weight of the tank. The second target requires a hydrogen volumetric density higher than 62 kg/m in order to limit the volume of the tank.
The Russian researchers from the Ceramic Thermal Materials Science and Engineering Centre focused their work on building an experimental hydrogen storage material with a gas weight content of around 60 kilogram and a volume content not less than 5% per cubic meter. Current traditional methods of storing nitrogen, either under high pressure in gaseous condition, or in liquid or adsorbed state, have low hydrogen parameters, both in weight and volume.
To develop their storage method, the scientists looked at various solid sorbents, based on carbon nanostructures - multi-layer nanotubes, astralenes (nanodispersible fulleroid systems) and fullerene-containing soot - which are activery studied around the world. They also analysed specialy treated palladium, magnesium hydride and their composites.
The researchers performed their tests at a special hydrogen test stand able to operate under temperatures from -180 to +800 degrees centigrade and with pressures varying from 0.0001 millimeter mercury column to 20 megapascals, as well as under various environmental conditions.
The scientists found that the inner cavities of all materials (central channels and interlamellar zones of nanotubes and astralenes) do not absorb hydrogen despite any type of specialized preliminary treatment for these materials. Enthusiastic researchers have tested palladium as a catalytic agent, but failed: this metal added only 1-1.5% to hydrogen absorption. Other nanomaterials - graphite fiber, activated carbon, pure fulleren dust, titanium powder and titanium metal hydride - showed much lower sorption values than powders of nanostructural materials.
Fullerene-containing soot appeared to be the winner among sorbent materials:
energy :: sustainability :: biomass :: bioenergy :: biofuels :: biohydrogen :: storage :: materials sciences :: fullerenes :: nanotechnology ::
The researchers prepared a powder of fullerene-containing soot, treated it with glycerol, and added magnesium hydride powder. These manipulations resulted in a sorbing agent the hydrogen sorbing parameters of which fit the requirements for hydrogen storages developed by the U.S. Department of Energy (DOE).
The new sorbent boasts the following parameters: the weight content of hydrogen slightly exceeds 5%, which leads to 65 kg in one cubic meter. Maximum absorption is shown under conditions of 200-350 degrees centigrade and 1-10 megapascals. The reverse process is highly effective at temperatures of 340-350 degrees centigrade.
Image: fullerenes are a family of carbon allotropes - molecules composed entirely of carbon, in the form of a hollow sphere, ellipsoid, or tube.
References:
Russian Information Center: New Horizons of Storing Hydrogen - August 30, 2007.
Article continues
Friday, August 31, 2007
Vienna UN conference: consensus on building blocks for international response to climate change
The conference concluded that industrialized countries should strive to cut emissions by 25 percent to 40 percent of their 1990 levels by 2020. Experts said that target would serve as a loose guide for a major international climate summit to be held in December in Bali, Indonesia. Critics have already responded that this range of cuts too broad.
The “Vienna Climate Change Talks 2007” were attended by more than 900 delegates from Parties, representatives from Intergovernmental Organisations, NGOs and members of the press.
They were designed to set the stage for a major United Nations conference in December in Bali. The meeting in Indonesia will seek to advance future action on climate change post-2012, when the first commitment period of the Kyoto Protocol expires.
Government delegates also debated how the response can be enabled by an approach that opens the way for financial flows to climate-friendly and climate-proof investments. This was based on a report on the investment and financial flows relevant to the development of an effective and appropriate international response to climate change, presented to the conference by the UN Climate Change Secretariat.
Alluding to the potential of the Kyoto Protocol’s Clean Development Mechanism (CDM), Yvo de Boer said:
The CDM permits industrialized countries to invest in sustainable development projects and thereby generate tradable emission credits:
energy :: sustainability :: bioenergy :: biofuels :: climate change :: greenhouse gas emissions :: Kyoto Protocol :: Clean Development Mechanism :: UNFCCC ::
The conference comprised the last workshop of the “Dialogue on long-term cooperative action to address climate change by enhancing implementation of the Convention” and negotiations under the Kyoto Protocol designed to identify emission reduction ranges of industrialised countries.
A number of Parties, including Indonesia as the host country of the UN Climate Change Conference 2007, in Vienna called for Bali to launch a formalised way to continue this work, which represents one of the options for taking the outcomes further.
At Vienna, the “Ad Hoc Working Group on Further Commitments of Annex I Parties (industrialised countries) under the Kyoto Protocol, the AWG, officially recognised the Intergovernmental Panel on Climate Change’s (IPCC) indication that global emissions of greenhouse gases need to peak in the next 10 to 15 years and then be reduced to very low levels, well below half of levels in 2000 by mid-century, if concentrations are to be stabilised at safe levels.
The group also officially recognised that avoiding the most catastrophic forecasts made by the IPCC, including very frequent and severe droughts and water-shortages in large parts of the world, would entail emission reductions in the range of 25-40% below 1990 levels by industrialised countries. The mitigation potential of industrialised countries increases through the use of the CDM.
References:
UNFCCC: Vienna UN conference shows consensus on key building blocks for effective international response to climate change [*.pdf] - August 31, 2007.
UNFCCC: Investment and financial flows relevant to the development of effective and appropriate international response to Climate Change - August 2007.
AP: Agreement Reached on Greenhouse Gas Curb - August 31, 2007.
Article continues
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