Engineers have created a chemical process that produces useful crude oil just minutes after engineers pour in harvested algae.
The system runs at around 350 degrees Celsius (662 degrees Fahrenheit) at a pressure of around 3,000 PSI, combining processes known as hydrothermal liquefaction and catalytic hydrothermal gasification. Such a high-pressure system is not easy or cheap to build, which is one drawback to the technology, though the cost savings on the back end more than makes up for the investment.
Douglas Elliott, the research engineer at the Department of Energy’s Pacific Northwest National Laboratory said “It’s a bit like using a pressure cooker, only the pressures and temperatures we use are much higher. 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.”
The products of the process are:
- Crude oil, which can be converted to aviation fuel, gasoline or diesel fuel. In the team’s experiments, generally more than 50 percent of the algae’s carbon is converted to energy in crude oil — sometimes as much as 70 percent.
- 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.
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