Biochar Production -  Oral Presentation
PyroDry – Our solution for biochar-production focused on wet materials
Andreas Hackl
Daniela Meitner
Jan Lindenberger
Next Generation Elements GmbH


The potential of the usage from biowaste, sewage sludge and other wet input materials as a resource for biochar production is undisputed. Our solution combines a high-temperature centrifugal dryer with a direct heated pyrolysis unit.

As input material for the system, wet material with a dry matter content around 20-25% can be used. These are for example sewage sludge from municipal sewage sludge treatment plants or from industrial production of foodstuffs, digestate from bigas plants, bedding form animal husbandry and many more. The hot exhaust gas from the pyrolysis is directly used in the dryer system at approx. 300°C and <17% oxygen content. So, no external thermal energy is needed for the drying process. After a very short drying time (4-8 minutes) the material with approx. 90% of dry matter is compacted in a pelletizing unit to a standard pellet form. These pellets enter the pyrolysis unit via a screw system. In the pyrolysis the material is processed around 650°C between 30 – 90 min. After the pyrolysis chamber the biochar is ejected again via a screw system to a big bag station. The pyrolysis gas is directly burned at 850°C for 2 sec. For the pyrolysis roughly 1/3 of the energy is needed for the pyrolysis itself. The rest is used in the drying unit.

There are 3 different types of the PyroDry system – PyroDry 1.500, PyroDry 3.000 and PyroDry 5.000. These numbers means that 1.500, 3.000 and 5.000 t/year of wet input (typically at approx. 20-25% DM) can be processed.

Beside the PyroDry system single use of the pyrolysis system called T:CRACKER® is possible if a heat sink (district heating, etc) is available. Some examples are hot water extraction, ORC-process or other industrial use can be envisaged. As input for the T:CRACKER® wood chips, annual crop residues, already dried biomasses e.g. from food industry etc. can be utilized.

Figure 1: PyroDry 5000 concept for processing of 5000 t/year of dewatered sewage sludge (approx. 20-25% DM)

References:
Sonnenerde - PyroDry 5000 (AUT)
Ökologische Klärschlammtrocknung Offenhausen GmbH - PyroDry 5000 (GER)
Hochschule Nordhausen - PyroDry 1500 (GER)
Farmer Shane - PyroDry 5000 (USA - Illinois)