Technology Focus: Flexible Solutions

Greenwood Energy’s feedstock preparation system supplied by Vecoplan has allowed it to adapt to changing streams to produce a consistent fuel pellet composition.

May 29, 2012
Renewable Energy From Waste
The Vecoplan feedstock preparation system installed at Greenwood Energy's facility in Green Bay, Wis., includes a series of grinders, shredders, magnets and conveyors.

Taking materials from the waste stream and turning them into a fuel product able to compete with traditional energy sources requires the proper formula. Getting the science right requires a feedstock preparation system be flexible to meet the demands of variable waste streams and to maintain consistency of the pellets.

New York City-based Greenwood Energy makes fuel pellets from waste materials including nonrecyclable paper, label waste, flexible films and nonwoven fabrics at its facility in Green Bay, Wis. What started out as a small scale operation quickly outgrew itself and Greenwood Energy needed to upgrade its facility to keep pace with incoming material.

The company was eager to increase production to meet capacity and in 2010 contracted with Vecoplan LLC, High Point, N.C., to upgrade its facility. Crews worked around-the-clock to get the system up and running as quickly as possible.

Vecoplan Sales Manager Mat Everhart recalls the fast-paced installation. “They were really on a tight schedule,” he says. “They had it installed in one month, working 24 hours in three shifts during the install. That was because they had an existing operation that wasn’t meeting capacity and they needed to do it quickly because they couldn’t afford the downtime.”

The installation was complete in March 2010 and has been running ever since with adjustments to the system being made as needed to accommodate different waste streams.

Vecoplan shredders are able to process a variety of materials. The high-torque motors utilize patented technology that, according to Vecoplan, is a special magnetic drive designed to reduce energy costs.

When material enters the tipping floor of the 60,000-square-foot-facility, it is sorted by Btu (British thermal unit) value. It is then taken to an infeed conveyor that feeds a Vecoplan VAZ 2500 2.5-meter-wide single shaft rotary grinder.

The VAZ 2500 processes 15 tons of material per hour and makes it into a preshredder size, says Everhart. “The whole point of the machine is simply material liberation so they can do separation,” Everhart explains.

Everhart points out that Greenwood Energy’s downstream system is extremely sensitive to metals “so what we do is take our system, process material through a preshredder machine and it comes out and hits a conveyor belt that takes it underneath a cross-belt magnet.”

The cross-belt magnet is sized to recover 95-plus percent of the ferrous metals within the material stream. Material then travels up a diverter conveyor until it encounters two VAZ 2500 RS reshredders. These particular shredders have smaller cutters and run on higher speeds than the preshredder to take material down to a 1.5-inch particle, says Everhart. After going through the reshredders, the particles travel through an enclosed conveyor for dust control and into a bypass conveyer that takes the shredded material up to three storage bunkers. The storage bunkers are positioned atop the pellet mills to feed the back end of the system.

Vecoplan shredders’ high-torque motors utilize patented technology that, according to Vecoplan, is a special magnetic drive that helps reduce energy costs.

Brad Goins, the project manager from Vecoplan on the installation says, “The nice thing about our equipment is that with the technology we have on our rotor motors, we are able to run various types of material. Our high-torque motors are a big selling point.”

The ability to run various types of material through the system has certainly been beneficial for Greenwood Energy, which accepts material in many forms, including bales, large rolls and pallets.

Greenwood Energy General Manager Ted Hansen says Vecoplan has been able to make adjustments to accommodate Greenwood Energy’s changing streams. “Even when we have processed materials outside the scope of the project, Vecoplan has responded and made modifications as needed to help us work through the change in scope,” says Hansen.

Another important reason for having to have a precise process is that Greenwood Energy produces an Environmental Protection Agency (EPA) qualified pellet. This means that the pellets they produce are considered paper pellets rather than waste pellets. In order to receive this designation, the pellet must maintain a 51 percent ratio of paper to plastics and other materials in the pellet. In addition, the pellets must have a steady Btu value, says Everhart.

In addition to supplying equipment, Vecoplan also provides engineering. The team at Greenwood Energy also is made up of people with engineering and paper industry backgrounds, which made it easy for both companies to collaborate on the system.

“Just seeing densities of material allowed us to work with their guys to be able to figure out what they needed,” says Everhart.

Hansen says working with Vecoplan significantly reduced the project risk. “Vecoplan was able to provide expertise, lab data and applications assistance to help us size the equipment and identify the right units in each application,” he says. “Vecoplan was able to design, integrate and install all of the equipment in a turnkey manner. They took time to listen to our needs and then provided multiple options to handle our requirements.”

Vecoplan was on site for installation, startup and commissioning of the new system. The company remained onsite for approximately 20 days to troubleshoot any issues that came up. But Vecoplan Engineer Justin Kennedy doesn’t need to physically be at the facility to see what is going on and to make adjustments to the system. He says he can do all of that from the comfort of his office.

“All of the controls for the pieces of equipment that we supplied are networked together through Ethernet communications,” he says. “I am able to connect to their entire network here and monitor, troubleshoot and make changes from North Carolina.”

Vecoplan also was able to work with the company’s existing PLCs (programmable logic controllers). “We took cutting-edge technology and we are able to network with their technology of 15 years ago. Every piece of equipment can communicate with each other to optimize the process,” says Kennedy.

If Kennedy goes a few weeks without hearing from Greenwood Energy, he says he can jump on his laptop to make sure everything is running smoothly. He says it is rare for a company the size of Greenwood Energy to utilize this technology, but he thinks it is the right way to go.

“Greenwood is pretty cool in that they are actually utilizing this newer technology to advance their company. Those guys are really doing it right,” Kennedy says.

Hansen recognizes the role that Vecoplan has played in Greenwood Energy’s success.

“Vecoplan has been instrumental in helping launch our business and has provided strategic assistance throughout the project,” Hansen says.

The preceding feature is sponsored by Vecoplan LLC, High Point, N.C. More information about the company is available at