What is torrefaction?

what is torrefaction

GMT : Green Metric Tonne / BDT : Bone Dry Tonne

 Torrefaction, a mild form of pyrolysis, refers to the heat-treatment of biomass at 250-320°C with little or no oxygen present.

The purpose of torrefaction is to remove moisture and volatile organic compounds (VOCs) from raw biomass, thus converting it to a solid, blackened, hydrophobic (weather-resistant) material.

The final product, known as torrefied biomass or biocoal (black or torrefied pellets), typically contains 70% of the mass and 90% of the energy content of the pre-treated material.

What is biomass?

AIREX web Biomass

Biomass is perhaps the oldest source of energy in the world.

Biomass energy is derived from recently-living organic matter such as sawmill waste, logging residues, low-grade biomass and agricultural residues.

  • Sawmill waste includes bark, off-cuts, planer shavings and sawdust;
  • Logging residues is the non-merchantable part of trees remaining after a forest harvest operation, such as top of trees, limbs, branches and needles/leaves;
  • Low-grade biomass are trees that are low quality for wood products due to shape, size, species or other traits;
  • Agricultural residues comprise sugarcane bagasse, corn stover and palm kernel shells.

AIREX web Technology Biomass Advantages of biomass

Advantages of biomass

  • Renewable – Sustainably-managed sources of biomass can provide fuel indefinitely.
  • Readily available – A significant amount of biomass is available in most regions of North America.
  • Dispatchable – A biomass-fired generation plant can increase or decrease electricity production in response to demand.

AIREX web Technology Biomass Biomass feedstock and the carbon cycle

Biomass and the carbon cycle

The use of fossil fuels releases carbon from ancient pools that cannot be replenished. Biomass, however, contains carbon extracted from the atmosphere. Through photosynthesis, the carbon contained in the atmosphere in a gaseous form is sequestered in a solid form in plants and trees. The carbon is then released again to the atmosphere through natural decomposition or combustion of the biomass. Therefore, there is no net addition of carbon to the atmosphere when biomass is used as a fuel to produce energy.

AIREX web Technology Biomass What makes biomass renewable

What makes biomass renewable?

Biomass must be sourced on a sustainable basis in order to be considered renewable. According to the United Nations Framework Convention on Climate Change (UNFCCC), biomass from forest lands is considered renewable if sustainable management practices are undertaken on these forest lands to ensure that the level of carbon stocks does not systematically decrease over time (carbon stock may temporarily due to harvesting).

Biomass feedstock in Canada is certified

The biomass used by Airex Energy originates from Canada, which has the largest area of third-party-certified forests in the world. According to National Resources Canada, as of the end of 2016, Canada had 168 million hectares of independently certified forest land, representing 37% of all certified forests worldwide. Third-party forest management certification complements Canada’s comprehensive and rigorous forest management laws and regulations. It provides added assurance that a forest company is operating legally, sustainably and in compliance with world-recognized standards for sustainable forest management.

CarbonFX Technology

Airex logo carbon fx

Airex Energy’s CarbonFX torrefaction technology allows industrial-scale production of a wide range of value-added biocarbon products.

By keeping precise control of both reactor temperature and residence time, CarbonFX delivers end products with unmatched quality, consistency and homogeneity.

AIREX web Technology CarbonFX Torrefied pellets

Biocoal (Torrefied pellets)
A drop-in replacement for coal in coal-fired power plants and cement/lime kilns

AIREX web Technology CarbonFX Biochar

A natural and organic soil amendment

AIREX web Technology CarbonFX Lightly torrefied wood flour

Lightly torrefied wood flour
For wood-plastic composites

AIREX web Technology CarbonFX Highly carbonized biocoke

Highly carbonized biocoke
For metallurgical applications

The CarbonFX Torrefaction Process

AIREX web Technology CarbonFX

The biomass fed into the unit is the size of sawdust. It is pre-dried in an aeraulic loop using residual heat from the combustion gas process. This reduces the moisture content of the biomass from 50% to 25%.

The conditioning chamber has four endless screws and a double wall. The combustion gases circulate in the double wall and heat the biomass through indirect contact. The moisture contained in the biomass is converted into steam and the biomass is conditioned in a saturated steam atmosphere. The biomass is then circulated by the hot flue gases from the combustion chamber to the torrefaction reactors.

Torrefaction reactor
Biomass is fed into the top of the reactor and spirals in the reactor following a downward cyclonic path to land at the base of the reactor, at the sustentation ring. The sustentation ring allows the biomass to remain suspended in the reactor, by creating a balance between the centrifugal force of the cyclonic effect, the gravitational force of the bulk material and the pushing effect induced by the sustentation ring. The total residence time in the reactor is very short, about 2 to 3 seconds.

The CarbonFX technology provides significant advantages to biocoal producers

AIREX web Technology Advantages Variety of feedstock

Multiple feedstock
The CarbonFX can process a large variety of feedstock including sawdust, bark, shavings, wood chips, recycled wood, agriculture residues and forestland biomass.

AIREX web Technology Advantages Homogeneous end product

Homogeneous end products
The highly turbulent flow inside the cyclonic bed reactor allows an optimal heat transfer rate and ensures very homogenous end products.

AIREX web Technology Advantages Easy transportation and assembly

Easy transportation and assembly
Modular design allows components to be shipped to site by either rail, sea or truck in standard containers with final assembly on site.

AIREX web Technology Advantages Low operating cost

Low operating cost
The CarbonFX operation is fully automated and highly energy efficient as the residual heat from the thermal process is used to pre-dry the biomass feedstock in an integrated system.

AIREX web Technology Advantages Cost effective

Cost effective
The CarbonFX system is simple to manufacture. It doesn’t require pressure vessels, biomass boilers, drum dryers, thermal oil heat exchangers or waste water treatment system.



Interested in learning more about our
CARBONFX system?

T: 450.661.6498

Head Office
2500 Bernard-Lefebvre Street
Laval, Québec, Canada, H7C 0A5


Bécancour Plant
103-4170 La Prade Blvd.
Bécancour, Québec, Canada, G9H 0B6

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