Carbofex (Biochar carbon removal)

Carbofex, a Finnish company founded in 2016, is one of Europe’s largest EBC-certified biochar producers. The company has developed a thermal pyrolysis technology that produces non-energent biochar from biomass while permanently removing carbon dioxide (CO₂) from the natural carbon cycle. One ton of Carbofex biochar removes 3.2 equivalent tons of CO₂ from the atmosphere. Since 2019, Carbofex’s solution has captured over 3,000 tons of CO₂. Carbofex was selected as one of the top 15 teams to receive a $1M Milestone Prize in the XPRIZE Carbon Removal competition.

Challenges: carbon emissions and biochar carbon removal

Carbon emissions

Since the early 1900s, carbon dioxide (CO₂) levels in the atmosphere have increased by 50% due to human activities. When fossil fuels (such as coal, oil, and natural gas) are burned for energy production, transportation, and industrial processes, CO₂ is released into the atmosphere. This excess CO₂ acts as a greenhouse gas, trapping heat and causing the air and ocean temperatures to rise. CO₂ emissions play a crucial role in driving climate change.

This warming effect has caused the global average temperature to rise by about 1.1 ºC since the pre-industrial period. This has led to rising in the frequency and intensity of extreme weather events, melting of polar ice caps and glaciers and rising sea levels, shifts in species ranges and increased risk of species extinction, agriculture and food security, and ocean acidification.

To mitigate these impacts, the Paris Agreement aims to limit global warming to well below 2 ºC above pre-industrial levels. The Intergovernmental Panel on Climate Change (IPCC) estimates that a “carbon budget” of about 500 GtCO₂, which corresponds to about ten years at current emission rates, provides a 66% chance of limiting global warming to 1.5 ºC.

Biochar carbon removal

Biochar removes CO₂ from the atmosphere through carbon sequestration. It starts with plants absorbing atmospheric CO₂ during photosynthesis and converting it into biomass. Biomass is converted to a stable solid biochar at high temperatures in the absence of oxygen. Biochar can endure in soil for thousands of years.

When biochar is added to soil, it acts as a carbon sink, storing the carbon that was previously in the atmosphere. This long-term carbon storage contributes to the reduction of CO₂ in the atmosphere, thereby aiding efforts to mitigate climate change. In addition to its carbon sequestration role, biochar improves soil performance by enhancing the retention and diffusion of water and nutrients.

Carbofex Technology

Carbofex has developed a simple and efficient thermal pyrolysis system that continuously converts biomass into non-energent biochar in the absence of oxygen. The biochar contains very few polycyclic aromatic hydrocarbon (PAH) compounds. This is accomplished by thermally treating the biomass inside a conveyor reactor system through the use of water vapor. Syngas produced in the conveyor reactor flows in the opposite direction of the traveling to-be-processed biomass. Syngas transfers heat to biomass. The cooled syngas is combusted by a gas burner to directly heat the conveyor reactor system. The entire process is self-sustaining.

Carbofex biochar technology

The diagram below depicts Carbofex thermal pyrolysis system.

Carbofex thermal pyrolysis system for producing biochar from biomass (ref. US20220169925A1)

The system primarily comprises a biomass supply element, a conveyor reactor system, a Thompson Converter type process space with a gas burner, a biochar discharge element, water supply elements, and a cooling element.

Biomass supply element

The biomass supply element introduces biomass into the conveyor reactor.

Conveyor reactor system

The conveyor reactor system is housed in a Thompson Converter type process space and closes relative thereto to prevent oxygen from entering the reactor. The conveyor reactor has a screw inside that moves the to-be-processed biomass to the region in the Thompson Converter type process space where the biomass is heated to pyrolysis temperature. The decomposition of biomass produces biochar, PAH compounds, and syngas.

Thompson Converter type process space

The Thompson Converter type process space houses the conveyor reactor system. It has a gas burner that combusts the syngas produced by the conveyor reactor. Heat is directly transferred from the combustion chamber of the process space to the conveyor reactor. Fuel gas exits the process space via an outlet.

Biochar discharge element

The biochar discharge element removes produced non-energent biochar from the conveyor reactor for further processing.

Water supply arrangement 1

The water supply arrangement 1 introduces water into the conveyor reactor’s end with the biochar discharge element. Water vapor forms in the conveyor reactor system. It has two benefits:

The water vapor cools and cracks the to-be-produced biochar before its removal from the conveyor reactor system;
Water vapor flows in the opposite direction of the movement of the to-be-processed biomass, preventing the to-be-processed biomass from becoming dry; and
Water vapor reduces/eliminates PAH compounds present in the biochar.

Water supply arrangement 2

Water supply arrangement 2 delivers water mist into the syngas to adjust its moisture and temperature. The management of syngas in terms of its temperature and moisture is important because, without water supply, the gas pipes will quickly become clogged if the to-be-processed biomass is dry.

Cooling element

The cooling element cools the produced non-energent biochar with a water circulation.

Carbofex continuous biochar production

Through the biomass supply element, biomass is introduced to the conveyor reactor system. Biomass moves inside the conveyor reactor and decomposes into biochar, PHA compounds, and syngas at high temperatures of 650 ºC – 750 ºC and in the absence of oxygen for 10 min.

Water vapor flows in the opposite direction of the moving to-be-processed biomass. The presence of water vapor prevents the biomass from drying out and reduces/eliminates the PAH compounds present in the biochar. It also cracks and cools the to-be-produced biochar.

The produced syngas, jointly with water vapor, flows in the opposite direction of the moving biomass and transfers heat to it. Thus, the syngas is effectively cooled and conducted to the gas burner of the Thompson Converter type process space. The combustion of the syngas directly heats the conveyor reactor. Flue gas is removed from the process space.

The produced non-energent biochar is removed from the conveyor reactor with a biochar discharge element at the end of the conveyor reactor for further processing.

Carbofex’s demo system can produce 140 kg of biochar from 500 kg of wood chips per hour.

Carbofex Patent

US20220169925A1 Method and apparatus for the manufacturing of non-energent biocoal with thermal treatment
OA20387A Method and apparatus for the production of unburned biochar with heat treatment
WO2020208303A1 Method and apparatus for the treatment of a water layer at a bottom of a body of water

Carbofex Products

Biochar market for carbon removal

Biochar is a solid material with high levels of carbon, made from feedstock biomass that offers compelling climate benefits. According to the IPCC 6th Assessment Report, soil carbon management in agriculture, like biochar projects, can reduce about 1.8 to 4.1 gigatons/year of CO₂. The market value of biochar for carbon removal can be assessed in terms of its price as a carbon credit and its overall market size.

The global biochar market size was valued at $184.90 million in 2022 and is projected to grow from $204.69 million in 2023 to $365.0 million by 2028 at a CAGR of 12.1% in the 2021-2028 period. In the U.S., the biochar market size was estimated at $125.3 million in 2020 and is expected to expand at a CAGR of 16.8% from 2021 to 2028.

Biochar carbon credits are typically priced in the range of $20+ per mtCO₂e, with some biochar projects selling credits for as high as $110 per mtCO₂e. For example, Puro Earth, a marketplace listing 23 biochar projects, lists prices for biochar-based carbon removal credits ranging from $98 to $200 per mtCO₂e.

Carbofex product

Carbofex operates a facility in Europe that can produce 1,000 tons of non-energent biochar and 600 tons of high-quality pyrolysis oil per year, as well as up to 8, 000 MWh clean energy as part of a municipal heating network.