Carbo Culture ($10M for Biomass Carbon Removal and Storage)

Carbo Culture, a Finnish climate tech company founded in 2018, has developed a carbon removal technology known as Carbolysis™, which uses a pyrolysis reactor operating at high temperature and pressure to convert biomass waste into stable biochar, thereby locking carbon safely away for centuries. Additionally, the process produces syngas that can be used to generate clean electricity. Carbo Culture believes that its technology is the most efficient method for converting biomass into biochar. Carbo Culture’s mission is to remove one billion tons of carbon dioxide from the atmosphere.

Challenges: carbon emissions and BiCRS

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.

Biomass Carbon Removal and Storage (BiCRS)

Biomass Carbon Removal and Storage (BiCRS) is different from Direct Air Capture (DAC) technology in that it lets plants do the hard work of scrubbing CO₂ out of the atmosphere through photosynthesis. It turns biomass into biochar or CO₂ that can be sequestered permanently, thereby removing CO₂ from the air.

One example of BiCRS technology is Bioenergy with Carbon Capture and Storage (BECCS). During BECCS, biomass is converted into bioenergy while carbon is captured and stored. The carbon in the biomass comes from CO₂ taken from the air during photosynthesis. Biomass is processed via combustion, pyrolysis, or other conversion methods. During the process, energy is extracted in useful forms of electricity, heat, etc., and CO₂ or biochar produced can be sequestered geologically or disposed of in landfills, respectively.

Carbo Culture Technology

Carbo Culture (Carbo) has developed a biomass pyrolysis technology based on Professor Michael J. Antal’s research. Carbo has developed a pyrolysis reactor that operates at a high temperature (750 ºC) and pressure (up to 400 psig) to efficiently convert biomass into stable biochar and sequester carbon permanently. Three tons of CO₂ are removed for each ton of biochar produced. The biochar can be used in agriculture, construction, and urban landscaping applications. The produced syngas can be used to generate electricity.

Carbo’s pyrolysis system is very efficient for biochar production. When the pyrolysis process of a batch of biomass contained in a canister within the reactor is complete, the canister is removed from the reactor without substantial cooling. The following canister filled with biomass waste is loaded into the reactor for the subsequent pyrolysis cycle.

Carbo Culture technology

The diagram below depicts the pyrolysis reactor system of Carbo for converting biomass to biochar.

Carbo Culture’s biomass pyrolysis reactor system (ref. US8585867B2).

The system primarily comprises an air compressor, a reactor, and a canister.

Air compressor

The air compressor supplies a stream of high pressure air to the reactor.

Reactor

The top of the reactor has a lid with a safety valve and a gas inlet coupling. The lid is open for loading or removing a canister from the reactor.

The reactor is a pressure vessel. The pressure vessel’s inner wall is an insulator that reduces heat loss from the canister during combustion and pyrolysis.

The bottom of the reactor has a flat electrical heater, which heats the biomass inside the canister. The flat heater is supported by a footing, which contains a duct that directs the flow of hot combustion gas to the outlet pipe.

The reactor has temperature and pressure sensors.

Canister

The canister’s top has a lid with a gas inlet coupling. The lid is open for loading biomass or removing produced biochar. At the top of the canister is a chain handle for raising or lowering it into the reactor.

The canister’s bottom is made of a metal screen or perforated metal to allow direct heating of the biomass, thereby facilitating its ignition.

How does Carbo Culture technology work?

The operation of the system comprises the following steps:

Load canister

Biomass, such as wood logs or sawdust, is fed into the canister.

After filling the canister with biomass, the canister is loaded into the reactor. The reactor is sealed.

Compressed air is supplied into the reactor. The internal pressure is typically raised to between 100 and 150 psi.

Pyrolysis

Then, electric power is supplied to the flat heater to heat the biomass, igniting and combusting it in the downward-flowing air environment. To minimize the input of external energy into the reactor, the heater is turned off two to four minutes after being activated.

When ignition of the biomass occurs, the temperature and pressure within the reactor will rapidly increase.

When the pressure reaches a predetermined limiting value (no more than 400 psig), the pressure regulator releases gas from the bottom of the reactor.

To achieve a temperature of 750 ºC throughout the biomass bed, additional compressed air is supplied to the top of the canister, and gasses are vented from the bottom of the reactor via a valve.

When the temperature of the top of the biomass bed reaches typically about 750 ºC, air delivery to the reactor is stopped by closing the valve.

Release gas

After complete pyrolysis, the pressure within the reactor is reduced to 0 psig by releasing gas via a regulator.

This high-temperature, high-pressure gas with little liquid tar can be burned in a gas turbine to generate additional power. Alternatively, it could be delivered to a gas engine, which would generate power by expanding the gas to atmospheric pressure.

Remove canister

After lowering the pressure within the reactor to atmospheric pressure, the canister is sealed (so that the hot biochar within the canister does not burn) and removed from the reactor without substantial cooling. The produced biochar contains >90% carbon and a negligible amount of polycyclic aromatic hydrocarbons (PAHs).

A following biomass-filled canister is loaded into the reactor for the subsequent pyrolysis cycle.

Since the reactor needs not be cooled between loads of biomass, Carbo’s pyrolysis system is very efficient and fast for biochar production.

A prototype of biomass pyrolysis reactor developed by Carbo Culture (Source Carbo Culture). — A prototype of biomass pyrolysis reactor developed by Carbo Culture (Source: Carbo Culture).

Carbo Culture Products

Market of Biomass Carbon Removal and Storage (BiCRS)

The BiCRS market is a niche segment of the carbon capture, utilization, and storage (CCUS) market. The CCUS global market was valued at approximately $2.1 billion in 2020. It is expected to reach $4.25 billion by 2025, growing at a compound annual growth rate (CAGR) of 15.2%. This growth is driven by increasing awareness of climate change, supportive government policies, technological advancements, and industry collaboration.

The majority of the CCUS market is currently focused on carbon capture technologies for fossil fuel-based power plants and industrial processes. However, the interest in BiCRS is growing due to its potential to remove CO₂ directly from the atmosphere and store it in a more sustainable manner. As the technology matures and gains wider acceptance, the BiCRS market is expected to experience significant growth in the coming years.

Carbo Culture products

Carbo Culture offers products of biochar, clean electricity, and carbon credits.

Carbo’s biochar that can be used in agriculture, construction, and urban landscaping applications. Its biochar is environmentally safe and a powerful soil enhancer due to its porous structure, negative charge, and large surface area. It helps soils retain water and prevent nutrients from leaching. This increases crop yields, soil structure, and carbon retention.

Carbo’s pyrolysis system can generate clean electricity by burning the syngas produced during the process. The excess electricity can be used to power and heat local homes and businesses.

Carbo offers carbon credits. Companies trying to reach their net-zero goals can buy these carbon credits, which represent the removal of carbon that can be measured, tracked, and verified. By buying these credits, companies can offset their carbon emissions.