Mantria, CDI develop commercial biochar plant

By Anna Austin
Posted June 11, 2009, at 2:33 p.m. CST

Green community development company, Mantria Industries LLC, and partner company, Carbon Diversion Inc., will soon have an industrial-scale biochar production facility on line in Sequatchie County, Tennessee.

The companies have formed a joint venture to develop biorefineries that transform biomass waste into biochar through a pressurized partially pyrolytic gasification system.

Mantria CEO Troy Wragg said the company expects to hold its "first burning" on Aug. 1, following a month of testing. "The facility is scheduled to be on line June 28, so we're just a few short weeks away from production," he said. Wragg said the plant will be the largest in the world, capable of producing almost 40,000 tons of biochar per year, or 8,000 pounds per hour when fully calibrated.

CDI has operated a pilot plant in Oahu, Hawaii, since 2004. "The pilot plant in Hawaii used a lot of coconut and macadamia nut shells-very high-carbon grade biomass waste which produces a very great activated carbon," Wragg said. "The main feedstock we'll be using here in the continental U.S. is any type of tree waste, such as slash and residuals. If we use pine waste, we'll do a burn for just pine waste. The next waste could be saw dust, and we have [the technology] down pat to where there's a different pressurization sequence and a different pyrolyic sequence for each type of feedstock, which can be varied and adjusted accordingly."

The companies have dubbed their biochar product "EternaGreen."

A standard CDI Carbonization process system consists of two 3.5-ton autoclave (reactor) units, which are pressurized and sealed once the biomass is loaded into canisters and placed inside. Electric heaters are turned on to ignite the feedstock then turned off, and the autoclave temperature is controlled by a dual-draft process. Under elevated pressure and heat, the feedstock will begin to carbonize at specific temperatures, ranging from 400 to 800 degrees Celsius (750 to 1,470 degrees Fahrenheit). During carbonization, gases from the process are pumped through catalysts, broken down into simpler compounds and sent through filters to scrub them. When the 25- to-40-minute process is complete, the biochar is set in a cooling pool for 24 hours.

"The beauty of our pressurization sequence is the fact that we're pelletizing and reconfiguring, so we're able to keep a much higher yield-about 65 percent to 70 percent, compared with others that get 35 percent, 45 percent, or maybe 50 percent yields," Wragg said.

At about one to two acres, a CDI system footprint is relatively small, and the equipment is built to be mobile. "We're able to focus on what we refer to as decentralized waste reduction-we can go into areas that have biomass waste problems like Tennessee, put one in any community or small-scale resort, or bring one to places such as Colorado with the pine beetle problems," Wragg said. "Once we're done in one area, we can move to another. When we look at approaching something sustainably, we have to look at it from a whole-systems approach, where you take into account transportation costs and how they increase carbon footprints, as well as other costs that are factored into taking waste from the outside area and bringing it to one central location. This is a way for us to go to the problem."

Plans are already in place to build a four CDI system biochar facility in another Tennessee location, which will be capable of producing 130,000 tons of biochar per year. Wragg said the facility should come on line by the end of September. "That's just the tip of the iceberg," he said. "We're really trying to capitalize ahead of our competitors, which are all on a pilot-scale basis right now. We're not just putting two large commercial projects in place; we're setting up for what we believe is a huge emerging market."

Wragg said the partner companies believe that after this year, biochar will be officially added to the United Nations' framework for climate change. "It'll be added in for its ability when planted in soil to serve as a carbon sink," he said. "When that happens, the worldwide demand for biochar will explode because now people are able to purchase biochar, plant it, and offset their carbon emissions. Carbon sequestration contracts will become a huge market in the long-term."