Ticking Time Bomb

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Drivers could soon be filling their cars with petrol created using algae thanks to a new process that converts the organisms into crude oil in less than an hour.
Engineers at the U.S. Department of Energy's Pacific Northwest National Laboratory (PNNL) have created a chemical process that produces useful crude oil minutes after they pour in harvested algae - a verdant green paste with the consistency of pea soup.
Now a biofuels company, Utah-based Genifuel Corp., has licensed the technology and is working with an industrial partner to build a pilot plant for mass production.
In the process, recently featured in the journal Algal Research, a slurry of wet algae is pumped into the front end of a chemical reactor.
Once the system is up and running, crude oil comes out in less than an hour, along with water and a byproduct stream of material containing phosphorus that can be recycled to grow more algae.
With additional conventional refining, the crude algae oil is converted into aviation fuel, gasoline or diesel fuel.
And the waste water is processed further, yielding burnable gas and substances like potassium and nitrogen, which, along with the cleansed water, can also be recycled to grow more algae.
The process creates :
Crude oil for fuelling vehicles
In the team's experiments, generally more than 50-70  per cent of the algae's carbon is converted to energy in crude oil
Clean water, which can be re-used to grow more algae.
Fuel gas, which can be burned to make electricity or cleaned to make natural gas for vehicle fuel in the form of compressed natural gas.
Nutrients such as nitrogen, phosphorus, and potassium — the key nutrients for growing algae.
While algae has long been considered a potential source of biofuel, and several companies have produced algae-based fuels on a research scale, the fuel is projected to be expensive.
The PNNL technology harnesses algae's energy potential efficiently and incorporates a number of methods to reduce the cost of producing algae fuel.
'Cost is the big roadblock for algae-based fuel,' said Douglas Elliott, the laboratory fellow who led the PNNL team's research.
'We believe that the process we've created will help make algae biofuels much more economical.'
PNNL scientists and engineers simplified the production of crude oil from algae by combining several chemical steps into one continuous process.
The most important cost-saving step is that the process works with wet algae.
Most current processes require the algae to be dried - a process that takes a lot of energy and is expensive. The new process works with an algae slurry that contains as much as 80 to 90 per cent water.
'Not having to dry the algae is a big win in this process, that cuts the cost a great deal,' said Elliott.
'Then there are bonuses, like being able to extract usable gas from the water and then recycle the remaining water and nutrients to help grow more algae, which further reduces costs.'
While a few other groups have tested similar processes to create biofuel from wet algae, most of that work is done one batch at a time.
The PNNL system runs continuously, processing about 1.5 litres of algae slurry in the research reactor per hour.
While that doesn't seem like much, it is a step closer to the type of continuous system required for large-scale commercial production.
The system runs at around 350C (662F) at a pressure of around 3,000 pounds per square inch, combining processes known as hydrothermal liquefaction and catalytic hydrothermal gasification.
Elliott says such a high-pressure system is not easy or cheap to build, which is one drawback to the technology, though there are cost savings.
'It's a bit like using a pressure cooker, only the pressures and temperatures we use are much higher,' said Elliott.
'In a sense, we are duplicating the process in the Earth that converted algae into oil over the course of millions of years. We're just doing it much, much faster.'
Elliott has worked on hydrothermal technology for nearly 40 years, applying it to a variety of substances, including wood chips and other substances.
Because of the mix of earthy materials in his laboratory, and the constant chemical processing, he jokes that his laboratory sometimes smells 'like a mix of dirty socks, rotten eggs and wood smoke'.
James Oyler, president of Genifuel, said: 'It's a formidable challenge, to make a biofuel that is cost-competitive with established petroleum-based fuels.'
'This is a huge step in the right direction.'
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