Making the world cleaner — one shell at a time

Thursday, July 28th, 2011
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By Cynthia Sweeney

North Hawaii News

People have known how to make carbon for a long time, about 10,000 years, but this is the first time it has been done with macadamia nut shells.

Big Island Carbon is using the discarded shells from macadamia nuts and turning them into activated carbon, a substance with hundred of uses from cleaning up our environment to accelerating existing sources of power.

“It’s simple in concept, but tricky technology,” said Rick Vidgen, CEO of Big Island Carbon in Kawaihae.

It turns out that the characteristics that make macadamia shells so hard are also the properties that make it an excellent feedstock for the production of activated carbon (AC).

AC’s superstar quality is that it is absorbent. It acts with a series of macro and micro pores, allowing materials in, but not out. Combined with an incredibly large surface area, just one gram of activated carbon has the surface area of roughly one-tenth the size of a football field. It is a very powerful substace for removing pollutants and other contaminants.

High quality activated carbon- not to be confused with the embers at the bottom of your BBQ- has many diverse uses, for everything from pharmaceuticals to hybrid cars. Ironically, the biggest use of AC is in removing the toxic mercury byproduct from charcoal burning factories. It is also used in water filtration systems, including cleaning municipal water problems, chemicals and pharmaceuticals and in waste water treatment. It is also used as soil amendment, removing chemicals from the soil, and for eons, it has been used as a remedy for the accidental swallowing of poison.

As Vidgen explained, the biomass conversion process is simple, but high-tech. The shells are heated in a carefully controlled process called “pyrolysis,” at a temperature of 920 degrees, which converts the shell into charcoal by heating in the absence of air. The charcoal is then super-heated in a special kiln, with steam at 1,800 degrees, which opens the pores in the charcoal, creating carbon.

BIC’s AC is extremely hard, about 90 percent of the hardness of a diamond. The higher the micro-pores in the surface area, the higher the grade the AC. This high-grade AC sells for $4 to $10 a pound, depending on its use.

The entire process is run from a control room, with six monitored computers. The product is also analyzed for quality daily. The operation is very clean, from the dust that is collected in the shake room, to the propane used to heat the kiln, to the biofuels that are burned off. These gas byproducts are turned into oil which help fuel the plant. And, the gas which is driven off during the charcoal process is run through a thermal oxidizer. In this form (carbon monoxide and carbon) it is acceptable to the EPA, and is “quite okay in the atmosphere,” Vidgen explained.

“There is virtually no pollution. That’s the way it was designed,” he said. “Everything is recycled, so we don’t throw away any heat. We’re very conscious of people (that live and work) around the place. We’re not going to have anything nasty here.”

Vidgen was the right person in the right place at the right time; a chemist working on a macadamia nut farm. Originally from Australia, where he studied industrial chemistry, Vidgen spent 30 years the mac nut industry, including a term as president of MacFarms of Hawaii from 1992-2003.

“Innovation breeds innovation. If one group of people sees this kind of thing happening, others will follow,” he said.

When fully operational, BIC will be able to generate about 1,500 tons of AC a year. The operation started six months ago, and is still in the testing stage, working out any kinks in this new-technology system, where one-of-a-kind parts can cost up to half a million dollars. The 45-foot kiln was damaged en-route, delaying the start of the operation for months. For Vidgen, this part of the operation is frustrating. His current headache is a malfunctioning water pump, and waiting for parts to be designed and shipped from Chicago.

“The good news is, the plant is totally integrated,” he said. “The bad news is, the plant is totally integrated.”

BIC is responding to the world’s increasing demand for products that clean up gas and liquid phase materials, eliminating pollutants and impurities. This high-grade AC will be sold to specialty users around the world.

“This industry is going ahead rapidly,” Vidgen said. “People have a thing about cleaning everything up.”

AC also has electro-magnetic properties which make it attractive to the electronics industry. It helps power flows focus and speed up currents. This use allows cell phones to heat up faster and provide electric cars with ultra battery capacity, which delivers immediate power for acceleration.

AC is produced elsewhere in the world using wood and other materials like wood, coconut husks in Sri Lanka and the Philippines, and olive pits in Europe. But this is the first time macadamia nut shells are being used for this purpose.

“Hawaii has got to think of this kind of technology. Tourism goes up and down, but we need something to keep the kids on the island,” Vidgon said.

BIC broke ground in 2009, and with 22 employees, the more local people employed here, the happier Vidgen is. The $40 million operation sits on four acres of land leased from the Department of Hawaiian Homelands, in Kawaihae’s industrial area. Denham Capital, an energy and commodities investor, is the primary funder. Kawaihae is an ideal spot for its proximity to the harbor, but more importantly for its dry climate. Currently, 20,000 tons of macadamia shells, which otherwise would have gone into a landfill, sit in “storage,” in huge mounds behind the factory.

It takes about 10,000 tons of macadamia nut shells to produce 1,000 tons of AC, and Big Island Carbon has a reciprocal relationship with the Hamakua Macadamia Nut company next door.

“It’s a positive, symbiotic relationship, with power sharing agreements. It’s green, it’s a big savings and it’s good all the way around,” said the Nut company’s President, Richard Schnitzler.

The Mac Nut company also uses a small percentage of their husks, which they crush into a fine powder, to generate fuel for their biomass boiler, which generates steam heat to dry the macadamia nuts. Some of the husks are also used as compost for their farms around the island.

So the next time you’re enjoying eating a few macadamia nuts grown on the Big Island, you can also think about how much you’re helping the environment.