Archive for the ‘greentech’ Category

Green tech: Engine fractionator

Friday, December 14th, 2007
Diesel engines are particularly polluting when running cold. Up to 95% of hydrocarbon emissions from these engines occur during the first 90 seconds of use, from a cold start.

Much of this come from burning cold fuel that has not vaporised properly and so burns inefficiently. One remedy that has been used with certain kinds of tractor engines, is to have a second more volatile fuel such as liquid petroleum gas that is used only when the engine starts.

But having a second fuel tank that needs to be filled up has proven impractical. However, ordinary diesel contains a small percentage of lighter hydrocarbons so Marcus Ashford from the University of Alabama in Tuscaloosa, US, has designed an on-board fractionation system that separates the lighter fractions of the fuel. This can then be used when the engine is cold thereby reducing hydrocarbon emissions.

Read the full on board fractionation patent application

Justin Mullins

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Green tech: Hydrogen purifier

Friday, December 14th, 2007
Many energy experts expect hydrogen to replace fossil fuels in future. But one problem standing in the way of a hydrogen economy is that the polymer exchange membranes used to generate electricity from the conversion of hydrogen and oxygen to water are easily contaminated by gases such as carbon monoxide and methane.

This contamination reduces the membranes' lifetime to such an extent that they cannot compete economically with fossil fuels.

So Timothy Golden of Air Products and Chemicals, a supplier of gases based in Pennsylvania, US, has come up with a way to remove contaminants from hydrogen by pumping the gas through an adsorbent material known as CaLSX – calcium low silica x-zeolite – at pressures of up to 1000 atmospheres.

This removes poisonous gases such as carbon monoxide and other gases like water vapour, oxygen, and nitrogen to leave pure hydrogen, which could significantly increase the lifetime of polymer exchange membranes. The team says that could provide a much needed kick-start to the hydrogen economy.

Read the full hydrogen purifier patent application.

Justin Mullins.

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Green tech: Kidney cell battery

Thursday, December 13th, 2007
One of the potentially useful things that a living cell can do is pump ions across its membrane. Simon Levinson, a biophysicist at the University of Colorado Medical School in Denver, US, says this generates a potential difference and so could be exploited to make a biobattery.

Levinson believes that kidney cells, which are particularly good at transporting ions, could be well suited to making a miniature battery. This would be formed by stacking up large numbers of cell layers to boost the voltage and current they can produce.

He suggests that such biobatteries might be ideal for powering devices inserted in the body, such as insulin pumps or pacemakers.

The cell culture could then draw oxygen and nutrients from the host's bloodstream. And, if the monolayers are made from immortalised cell lines, the biobattery should live as long as the host.

One problem, however, is producing biobatteries with the kind of voltages needed to run medical devices. But Levinson says he is working on it.

Read the full biobattery patent application.

Justin Mullins

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Green tech: Biofuel bug

Tuesday, December 11th, 2007
An alternative energy company called SunEthanol based in Massachusetts, US, hit the headlines earlier this year when it claimed to have found a naturally occurring organism called "Microbe Q" that could convert waste biomass such as corn stalks, sawdust and grass cuttings into ethanol.

This is important because bioethanol could replace petrol as a fuel for internal combustion engines. Ethanol can already be made from biomass, but requires a multistage process employing enzymes to break down the cellulose before the biomass sugars can be fermented.

Now the company has filed a patent application for an industrial process that employs a microbe called Clostridium phytofermentans. The organism was discovered by company co-founder Susan Leschine and colleague Tom Warnick from the University of Massachusetts at Amherst, US, in soil near the Quabbin Reservoir in Massachusetts.

They say this naturally occurring anaerobic microbe can produce ethanol in a composting tank, in which biomass is fermented in the presence of the microbe. The process works without the need for enzymes of any kind, making it potentially cheaper than other approaches.

The company has already attracted funding from several investors.

Read the full Q microbe patent application.

Justin Mullins

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Green tech: Buckyball filter

Monday, December 10th, 2007
Methanol fuel cells are increasingly touted as potential replacements for conventional batteries in everything from cellphones to laptops. They work by allowing protons from the methanol to flow across a membrane to generate current.

But the membranes they employ have a significant disadvantage – in addition to protons, they allow methanol to cross over as well. This dramatically reduces the efficiency of the fuel cell, not least because the methanol that passes through is wasted.

NowFred Wudl, an organic chemist at the University of California, Los Angeles, US, and colleagues say it is possible to block the passage of methanol through the membrane by plugging gaps within its structure using buckyballs – nanosopic spheres of carbon.

The buckyballs – also called fullerenes – would have chemical groups attached to them that shuttle the protons across the membrane while blocking the progress of methanol molecules.

Membranes made this way would have the potential to dramatically improve the efficiency of Methanol fuel cells, Wudl says.

Read the full buckyball membrane patent application.

Justin Mullins

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