Maine Woods Pellet (MWP) are operating a state-of-the-art wood pellet production facility in Athens, producing in excess of 105,000 t/a residential wood pellets which makes them the largest pellet manufacturer in the state of Maine. MWP secured a power purchase agreement with Central Maine Power and were granted a new market tax credit incentive for this project.
The new biomass-fired thermal oil energy system utilizes wood waste from MWP’s forestry operations such as logging and sawmill residues. Even though the combustion system was optimized for highest possible efficiency, the flue gases are still having considerable sensible heat.
In order to minimize the stack losses, SolaGen installed a rotary dryer system downstream of the CAW heater system to pre-dry the feedstock for the existing pellet plant. The system features a 10 x 40 single-pass drum, stack gas recirculation, and high efficiency emission controls.
With this new approach MWP are not only generating a new revenue stream by feeding green power to the grid, they are also increasing their pellet plant production capacity.
After all, this is the first biomass project to fully qualify for “Massachusetts Standard Class 1” regulations for renewable energy credits!
In light of major benefits such as reduced operations and maintenance costs offered by thermal oil and ORC-technology, MWP decided in favor of an ORC-unit over a traditional steam Rankine Cycle system.
CAW designed and manufactured the biomass combustion system with a nameplate capacity of 31.5 MWth which features a single five-section reciprocating grate with a total grate surface of 56 m2. The thermal oil heater system consists of a radiant coil with a length of almost 19 meters and three additional convective tube banks.
SolaGen supplied the new rotary drum dryer with woodyard handling equipment and energy system controls as the key system for MWP’s pellet business. Turboden from Brescia in Italy supplied a type 80 HRS ORC-unit to generate 8 MWel.
The design and engineering of the plant was done by WGL Technical Inc. from Prince George in B.C., Canada. Mid-South Engineering Co. took care of the balance of plant and the system integration of the entire project. All the parties worked closely together to implement this sophisticated project in time and to MWP’s full satisfaction.