Clean Tech's Hot New Tool

Smaller and more practical electron-beam emitters could save millions of tons of C0₂ emissions.

Electron-beam emitters that are one-hundreth the size and cost of conventional electron emitters could usher in a wide array of new uses for the devices that could dramatically cut the energy use of industrial processes. Advanced Electron Beams (AEB), a Wilmington, MA, startup, has developed a small, low-powered electron emitter that is the size of a microwave oven, compared to the conference-room equipment now needed for electron-beam processes.

Beaming in: Electron-beam sterilization of the inside of a beverage bottle causes the walls of the bottle to fluoresce when exposed to electron emissions. Credit: Advanced Electron Beams

"We think AEB is the most cutting-edge industrial-efficiency technology that we've seen in the 10 years we've been doing clean-tech investing," says Charles McDermott of RockPort Capital Partners. In August, RockPort and several other venture capital firms announced the investment of $14.2 million in AEB.

Electron-beam devices have been around for decades and are used in sterilization and curing processes for coatings and paints. The units' large size, however, makes it difficult to incorporate them into assembly-line manufacturing. For example, syringes coming down an assembly line, McDermott says, currently have to be collected in batches, transported to a separate room housing the electron beam, radiated with electrons, and then returned to the assembly line. Fitting the smaller beam emitters into assembly-line operations will also make it easier to use them for curing paint, rustproof coatings, and varnishes on metals, woods, and plastics--a process that is often now done using energy-intensive drying ovens.

AEB, which sold one of its emitters to Ford Motors for research and development, estimates that the heat required for all conventional thermal curing in the United States is responsible for 5 million tons of carbon dioxide emissions per year, the annual output of roughly 1 million automobiles. Curing also produces an additional 250,000 tons of volatile organic compounds--gases produced by heating organic solvents--that are typically combusted in abatement treatments that yield additional carbon dioxide emissions.

To shrink the size of its electron beams, AEB simplified the design of its emitters. For example, conventional electron emitters use vacuum pumps that run continuously to maintain a vacuum space inside the emitter that is essential for generating electrons. AEB's device, however, seals the vacuum inside so it doesn't need pumps.

An additional benefit of AEB's design is that its emitters can be mass produced, and, unlike conventional emitters that are often one-of-a-kind installations, they can be easily replaced if something goes wrong. "They are like lightbulbs. If you have a failure, you swap [them] out like a lightbulb, [whereas with a] mainframe version, you are flying out a technician, and it may be down for weeks," says McDermott.

The small size and precision tuning of AEB's emitters allows them for the first time to direct a cloud of electrons inside the mouth of beverage containers. Plastic bottles holding sugary, noncarbonated drinks, including energy drinks and fruit juices, either have to go through a chemical wash and subsequent rinsing prior to being filled, or the beverage has to be poured in at 180 degrees Fahrenheit to sterilize the inside of the container. A new electron-beam emitter first unveiled by AEB in September can now send a nozzle inside bottles and sterilize the inner surface by breaking apart the chemical bonds of any lingering bacteria. Sterilization is completed in milliseconds, requires no rinse water, and, compared to thermal sterilization, cuts energy use by 40 percent.

In all, AEB has sold more than 200 of its $100,000 devices to companies and research institutions, including General Electric, which is testing the technology at its research center in Niskayuna, NY.