Source : http://green.blogs.nytimes.com/2009/09/16/a-new-way-to-turn-plastic-into-fuel/
Envion Envion, a Washington, D.C., start-up, aims to turn plastics into fuel — with minimal mess.
Entrepreneurs have been trying for years to turn low-value wastes into high-value products. Waste plastic is among the lowest in value, and gasoline or diesel fuel the highest, but machines that carry out that conversion usually consume a lot of energy and get gummed-up by leftover materialthat they cannot convert.
Now a company in Washington, D.C., is trying out a new way — heating the plastic to a very carefully controlled temperature range, with infrared energy.
The company, Envion, is expected to cut the ribbon on Wednesday morning on a $5 million plant that it says will annually convert 6,000 tons of plastic into nearly a million barrels of something resembling oil. The product can be blended with other components and sold as gasoline or diesel.
“We are the world’s largest oil consumer and the world’s biggest producer of waste,’’ said Michael Han, chairman and chief executive of the company.
This process will convert one to the other for about $10 a barrel, he said.
Montgomery County, just north of Washington, D.C., apparently agrees, at least to the extent that it is giving Mr. Han a free supply of plastic and a spot at its waste transfer station to set up shop.
Gov. Martin O’Malley of Maryland was scheduled to speak at a ceremonial opening on Wednesday.
A day earlier, Mr. Han pointed out bales of plastics waiting to be shredded and fed into his machine, including planters, McDonald’s large-sized beverage cups, margarine containers and other materials typical of what suburban residents put out in blue bins once a week for pick-up.
His machine can digest the blue bins, too, he said.
Indeed, the machine will take everything except PET (the bottle with the “1’’ on the bottom) because those have a higher value on the recycling market, he said.
He will process the caps, though.
(Nationwide, 50 million tons of plastic waste are generated annually, according to the company.)
The finished product looks like a slightly murky lemonade and smells somewhere between gasoline and diesel fuel. One company has already agreed to buy the material for blending into motor fuel, and Mr. Han said he is in discussion with others. Envion would like to license its technology for use around the world.
Mr. Han and other company officials were a little vague on some details, which they said were proprietary, but the plant essentially consists of a two-story-high chemical reactor with an internal agitator (for mixing up the soup) and heating elements that give off infrared energy.
Another trick is to limit the amount of oxygen.
Because the process is driven by electricity and not with an open flame, the temperature can be tightly controlled, so most of the material — about 82 percent, according to the company — becomes liquid fuel.
Company executives predicted that they would have to shut down to clean out leftover sludge two to four times a year (conventional processes get clogged much faster).
The sludge can be burned for energy too, but it has much lower value.
Production depends on the plastic used as feedstock, but each ton of waste will produce 3 to 5 barrels of product, according to Envion. Producing a barrel consumes between 59 and 98 kilowatt-hours — two or three days’ worth of electricity for a typical house. The price of electricity per gallon comes to 7 to 12 cents, the company says.
Todd Makurath, the director of global brand management at the company, said that because it was all electric, it could be monitored over the Web, with just two employees on site, one to use a front-end loader to dump shredded plastic into the intake hopper and another to “watch for red lights” on the alarm system.
“This could be transformational in how we handle plastics,’’ Mr. Makurath said.