Mobile power reactors could turn plastic garbage into gasoline and diesel fuel.
Mobile plastic fuel. I’m Bob Hirshon and this is Science Update.
In Back to the Future II, Marty McFly fuels his DeLorean by stuffing garbage into a Mr. Fusion energy reactor. While that’s science fiction, garbage-powered transport may really be in our future. At a meeting of the American Chemical Society, researchers announced that they’ve developed a small reactor that can convert the plastic trash that’s littering our oceans into gasoline and diesel fuel. The project is the brainchild of sailboat captain James Holm and organic chemist Swaminathan Ramesh of EcoFuel Technologies. Ramesh says the machine sets off a chemical reaction that efficiently breaks down plastic into fuel. No further refining is needed, a big money-saver.
So you produce the fuel and use the fuel to run your boat. It’s self-contained.
Ramesh says a larger version could power a small city without the need for a costly power plant. I’m Bob Hirshon, for AAAS, the science society.
Making Sense of the Research
Since the first development of petroleum-based plastics at the beginning of the 20th century, plastics have become a ubiquitous part of life. They are used in an enormous and expanding range of products, from paper clips to spaceships. They have already displaced many traditional materials, such as wood, stone, horn and bone, leather, paper, metal, glass, and ceramic, in most of their former uses. In developed countries, about a third of plastic is used in packaging and another third in buildings, such as in piping used in plumbing or vinyl siding.
Its widespread use shows that plastic is a very useful material. The problem with plastic arises when it is disposed of. Plastic has a very slow decomposition rate, which means that it can take up a lot of space in landfills and, when not properly thrown away, often ends up in the water where it is gradually broken down into small particles that can be ingested by marine wildlife.
Efforts to control plastic waste began in the late 20th century with recycling efforts. However, according to a study that appeared in Science in 2015, only a very small portion of plastic is recycled. Instead, as much as 12.7 million metric tons of plastic waste finds its way into the ocean every year.
James Holm and Swaminathan Ramesh hope to rectify this problem with the device they are developing, which is a mobile reactor that could transform plastic into diesel fuel. The idea of converting plastic into fuel isn't a new one. The typical method for converting plastics into fuel is pyrolysis, which involves breaking down the long hydrocarbon chains in plastic at moderately high temperatures in the absence of oxygen, followed by several refining steps. The method can be energy-intensive, expensive, and time-consuming.
Ramesh set out to change the game and developed a catalyst that, when deposited on a porous support material and coupled with a controlled pyrolysis reaction, yields diesel fuels directly without further refining. It is also cost-effective on a small scale, runs at lower temperatures, and is mobile. The device weighs around 500 pounds and the whole system can fit in a 20-foot shipping container or on the back of a flat-bed truck. The machine can convert about 10 pounds of plastic into one gallon of diesel. Depending on the needs of the people using it, the machine can be configured to convert anywhere from 200 to 10,000 or more pounds of plastic per 10-hour day, which means it can create between 20 and 1,000 gallons of diesel a day.
Holm and Ramesh are now setting out to show that the technology works. They will soon conduct a demonstration project for the government of the city of Santa Cruz, California. Officials there are interested in implementing the technology to address waste plastics that currently cannot be recycled, as well as to formulate diesel fuel the city can use for its vehicles.
Now try and answer these questions:
- What kinds of products is plastic used in?
- Why does plastic pose such a problem when it is thrown out?
- What kinds of efforts have been undertaken to deal with plastic waste?
- What are James Holm and Swaminathen Ramesh developing to combat the problem of plastic waste?
- How does the device work? How much diesel fuel can be created from 10 pounds of plastic?
The Science Update Podcast on Chemistry & Life makes a nice tie-in to this one. It features what 2-billion-year-old raindrop fossils can tell us about conditions on the early earth, what science is revealing about the artwork of Leonardo da Vinci and Vincent Van Gogh, and a breakthrough in materials science technology that yields plastic that can repair itself.
In the Ocean Plastics Science Update, hear how scientists are getting a better handle on how much plastic we put into the oceans and what effects it’s having.
You can use this Science Update to build on student interest in the problem of dealing with all of the waste that humans generate. The mobile device that Holm and Ramesh are building is one solution to that problem. Ask students if they can think of other solutions. You could challenge them to use the information they learn here to generate ideas for their own solutions and then to set about researching those potential solutions and coming up with plan for designing and building prototypes.