C-Green Technology enables efficient treatement of wet biowaste such as sewage sludge and bioreactor digestate. Through Hydrothermal Carbonization (HTC), it converts these materials into HTC biocoal, a dry, sustainable carbon product also known as hydrochar.
C-Green offers efficient sludge handling. Through the HTC process, sludge is treated in a reactor for one hour at approximately 200 °C. During the process, an aqueous phase forms containing inorganic and organic water-soluble components, along with a slurry phase made up of biocoal particles. As the pressure is reduced, steam is generated. This steam is recycled and injected at the start of the process to preheat the incoming sludge, significantly reducing the need for external energy input. The separated water is sent back to the wastewater treatment plant. If the plant has biogas production, it is possible to increase biogas output using the separated water. Finally, a high-capacity chamber filter press, the same type widely used in the mining and food industries, is employed for efficient dewatering of the HTC slurry, creating a carbon-rich material called HTC biocoal, also referred to as hydrochar.
One C-Green HTC facility has the capacity to process up to 30,000 tons of wet sludge per year, the amount typically produced by a city of 300,000 to 400,000 people.
C-Green’s HTC plant is highly flexible and can convert almost any type of wet biowaste, regardless of whether it is digested, non-digested, or has varying moisture content.
Biowaste suitable for the HTC plant includes:
– Sewage sludge
– Biogas digestate
– Manure
– Food waste
– Industrial biosludge
– Agricultural residues
– Fiber bank sludge
– Algae and seaweed
What is HTC biocoal?
HTC biocoal, also known as hydrochar, is a solid product formed after dewatering slurry from the HTC process. It is sterile, odorless, and storable, with considerably less volume and weight than wet sludge, as much as 80% less. Biocoal has a dry solid content (DS) of between 55-70%, with a heat value of an average of 10 GJ per ton (or 2.8 MWh/ton), about 25% of the heat value of oil.
HTC biocoal can be used in a combustion plant designed for waste incineration as well as biofuel for heat and power production. It can also be used as a biosolid fertilizer or as soil improvement, if the environmental threshold limit values are not exceeded.
