There are no industry standards for wood biomass products; rather, each plant sets its own criteria.
"The nomenclature and terminology in the industry are fairly unrefined," says Joshua Streblow, Riverdale Environmental Services. "When you talk about a 2-in. minus or a 4-in. minus, there is not an industry standard on what exactly that means. It really boils down to the plant's individual needs. There is no way around the sampling and talking with the plant to find out what their actual needs are."
Many plants only take chips, while others may accept ground material or both. With every plant having unique specs, it pays to seek out professional help. "We rely heavily on our dealer network out in the field to work with customers to get the end product and material volume they need," says Todd Roorda, Vermeer Mfg.
The equipment you use will have a major influence on how effectively you can meet certain specifications. Dozer Enterprises uses a Morbark Model 40/36 set up specifically for producing fuel chips. This single-drum chipper replaced two older disc chippers in the fleet.
"We do as much with this brand new chipper for biomass than we used to do with the old chippers," says Joe Miller. The disc chippers were capable of producing either paper chips or fuel chips. "All we do is fuel chips and we had a lot of maintenance on the older chippers." The drum chipper is also much cheaper to operate.
Morbark is also able to modify its horizontal grinders to produce 1/4-in. minus product or fuel chips. "We simply convert our grinders to chippers with a Quick-Switch conversion kit, which can be installed in the field very quickly," says Ed Dodak.
Bandit Industries offers a chipper knife setup for its horizontal grinders, as well. "Customers can easily change the cutter mill on our horizontal grinders to a chipper knife setup, which is a real simple task," says Jerry Morey. "It can be done in as little as 2 1/2 hours.
"We offer a large variety of screens and different teeth based on the material [the customer wants] to process and the product they need," he adds. "We are working with the customer out in the field and we customize our equipment to meet their needs."
Vermeer's HG6000 and HG6000TX horizontal grinders can also be customized for biomass materials using a specialty fuel chip attachment. In addition, local dealers have the expertise to set the machines up to specific requirements. "Traditionally, we have been able to get to the majority of [end-product] specs," says Roorda.
Riverdale Environmental relies on Vermeer tub and horizontal grinders. "The bulk of our work is with the tub grinder, but we do use a horizontal grinder, as well," says Streblow. "For the larger facilities, it is typically not a problem [to meet specs with the tub grinders].
"Where you start running into a problem is once you get into the more refined biomass plants," he continues. "They tend to be the smaller scale plants that are taking in under 100,000 tons annually. They will have a tighter spec on their material. There is the need for consistency in the product. You have a hard time getting that kind of consistency out of a tub."
It becomes a balancing act between the optimum end product and versatility. "We would like to be able to make the best biomass chip possible. However, we also must balance that with appealing to the largest market possible in creating our equipment," says Mark Ferguson, Fecon. "For example, our RTC 22 makes a very consistent biomass-type chip. It should meet 99% of the specifications. Our bio-harvester provides less of a chip and more of a mulch. The product is going to meet a lesser percentage of specifications on the market."
On the other hand, the chipper requires other machines to feed material, while the bio-harvester allows processing with a single machine. "Your costs are significantly less with a one-machine operation," Ferguson points out.