Hydrothermal Carbonisation (HTC)
The hydrothermal carbonisation process includes the chemical and physical dehydration/dewatering of biomass. The chemical dehydration involves the elimination of water molecules from hydroxyl groups. The physical dewatering step is facilitated by the lower viscosity of water, the dissociation of colloidal substances and fewer hydrophilic functional groups at HTC pressures and temperatures. These phenomena facilitate the dewatering of HTC-coal by comparison with wastewater sludge or other biomass. Thanks to the hydrophobic nature of HTC-coal, the use of AVA-CO2 technologies yields dewatering rates of more than 70 % dry matter content without the addition of polymers. Since HTC conditions destroy cell structures in the biomass, the residual water exists only in the form of surface water. These conditions are well-suited for simple and cost-effective additional drying to 90% dry matter content or higher. An Unbeatable Advantage.
Robust and Reliable Multi-Batch Procedures
The HTC procedure developed by AVA-CO2 is a redundant multi-batch process. Due to the high redundancy and simple operations, the process excels in reliability. The HTC plants offered by AVA-CO2 have a modular design. This guarantees maximum flexibility. As a matter of principle, we use tried and proven industrial standard components. This makes our plants robust and reliable.
The excellent carbon balance of the HTC technology and the intelligent process management for the recirculation of HTC process water allows it to utilise more than 90 % of the carbon in the biomass.
The hydrothermal carbonisation has an important advantage. The HTC method dewaters wet biomass more efficiently than any other technology. According to a study performed by the Zurich University for Applied Sciences (Switzerland), the HTC process saves up to 61% thermal energy and up to 69% electrical energy compared to traditional thermal drying methods.
Only a comprehensive analysis can answer the question whether a process works correctly and efficiently. This includes the analysis of the energy used to establish a source of energy as well as evaluations of the energy product itself and the energy used for the construction of the respective production plant. A reliable view can only be established after reviewing all aspects and resources used. Only then can it be said whether one process is superior to others.
The ZHAW (Zurich University of Applied Sciences) study commissioned by the Swiss Federal Office for Environmental Affairs confirmed the advantages of HTC in a large comprehensive study, which compared the eco-balance sheets for different processes. Read more here » Schlussbericht_BAFU_HTC_2013 (final report of the Swiss Federal Office for Environmental Affairs)