HM3 Energy, Inc.
Process: 2nd generation biomass energy cleaner and more energy efficient by using torrefaction in process
First the biomass waste is ground, if necessary. Wood waste such as forest waste is received as ground hog fuel. HM3 Energy's process uses dirty biomass as feedstock., not clean wood chips. Key HM3 Energy TorrB™ processes include integrated drying and torrefying, where the exhaust gases are captured and conditioned then burned to provide process heat in the dryer. All process heat is provided by an average of 10% of the feedstock energy.
Following a cooling section to reduce the mass temperature to a medium temperature, the friable, dry, brown mass is fed to a briquetting/pelletizing machine. Here, under compressive force of several tons per square inch, the mass is transformed into dense briquettes. These HM3 Energy TorrB™ torrefied biomass briquettes are expected to have an energy value of approximately 10,000 BTU per pound, very comparable to coal.
The torrefied briquettes are then temporarily stored before shipment in truck or railcars to the regional power plant. Torrefaction transforms woody biomass so that it absorbs very little water, enabling the HM3 Energy's TorrB™ product to be stored outdoors and shipped in open hoppers – just as coal is.
The thermal process is environmentally friendly, as the volatile organic compounds released by heating the raw biomass are separated and burned cleanly in the dryer. Emissions will be less than other biomass power or coal power plants.
Furthermore, the energy required to dry, torrefy and briquette our torrefied biomass is much less than that of producing standard wood pellets, for two reasons:
- HM3 Energy's TorrB™ torrefaction process uses a small portion of the feedstock for its energy needs (unlike traditional pellets, which need a large amount of outside energy).
- Because our torrefied biomass is not fibrous (like wood chips used to make standard wood pellets) it requires far less energy to grind and briquette.
See downloadable PDF chart: Production Energy Balance: Traditional vs. Torrefied Pellets
Challenges and Solutions in Producing Torrefied Wood Briquettes from Woody Debris
Torrefaction facilities can be built in convenient locations to access feedstock such as urban wood waste, agricultural residue or dedicated crops. However, one of the most expensive challenges of utilizing forest or rangeland woody debris as a heat source has been the cost of transportation. Since forest waste is normally wet and bulky, it is prohibitively expensive to transport long distances. To meet this challenge, HM3 Energy plans to produce dense torrefied wood briquettes in proximity to the harvest site of woody debris on forest and rangelands by sizing each commercial plant appropriately for the quantity of feedstock locally available on a sustainable basis. The transportation cost of the dense, water resistant torrefied pellets is expected to be one tenth or less in comparison to transporting raw forest waste.