Biochar technology brings together sustainable energy, waste management, and environmental science, with many in the sector waiting for a true disruptive solution. PYROCO™, rooted in research on biosolids-derived carbo-catalysts, offers exactly this kind of transformative potential. It uses affordable, activated biochar from biosolids for catalytic biomass pyrolysis, particularly spent Eucalyptus nicholii. This approach provides an efficient and scalable model that can compete with expensive commercial catalysts in the biochar and bio-oil markets.
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Fundamentals of the PYROCO™ Approach
At the heart of the PYROCO™ system lies a clear technical strategy: employ biosolids as a feedstock for preparing activated biochar, then use this material as a catalyst to upgrade the vapor byproducts of biomass pyrolysis.
Biosolids, which are semi-solid byproducts from wastewater treatment, possess inherent metals and complex organic matter. They present both a waste management problem and a resource opportunity. Traditionally, the disposal of biosolids faces hurdles due to the heavy metal content, which limits their use in agriculture.1,2
The PYROCO™ technology finds value here by converting biosolids into functional catalysts via thermochemical activation. Using activating agents such as phosphoric acid, the process creates catalysts with high surface area and enriched functional groups. These catalysts efficiently upgrade pyrolysis vapors from lignocellulosic biomass, such as spent Eucalyptus nicholii, improving the yield of valuable phenolics and hydrocarbons.
This biowaste-derived catalyst reduces reliance on costly metal-based catalysts. Its eco-friendly and economical nature improves sustainability and provides tailored catalytic properties by adjusting activation methods.1,2
Reactor Design and Operational Dynamics
The PYROCO™ model centers around a quartz tubular reactor, which can be adjusted for continuous or batch processing. Inside the reactor, quartz wool separates the feedstock and catalyst, creating distinct reaction zones for ex-situ catalytic pyrolysis. Nitrogen acts as a carrier gas to maintain an oxygen-free environment. This setup helps achieve the right conditions for pyrolysis and stabilizes volatile compounds during the process.1,2
Optimal yields are achieved at intermediate pyrolysis temperatures of around 400 °C. At this temperature, the phosphoric acid-activated biochar (PAC) catalyst shows the best selectivity for both phenolic compounds and hydrocarbons. The reactor system can operate in ex-situ and in-situ modes, offering complete flexibility for large-scale industrial use. With the ex-situ method, vaporized products from biomass can pass through a separate catalyst bed, which allows for the adjustment of product distribution by changing the catalyst properties without affecting the feedstock.1
Chemistry of Catalytic Upgrading
The technical centerpiece of PYROCO™ is its use of biosolids-derived activated biochar as a catalyst for the selective upgrading of pyrolysis vapors. When Eucalyptus nicholii is pyrolyzed, the biomass breaks down into biochar, bio-oil, and gases. Without a catalyst, the bio-oil contains many unwanted oxygenated compounds, reducing its stability and heating value.1
Activated biochar catalysts from biosolids improve pyrolysis bio-oil quality by promoting deoxygenation, decarboxylation, and cracking of oxygen-rich molecules. PAC is particularly effective because it has a high surface area and Bronsted acidic sites. This helps produce bio-oil with improved quality and value, containing up to 69.7 % phenolics and 13.7 % hydrocarbons.1
Advantages in Feedstock Flexibility and Waste Valorization
A standout feature of PYROCO™ is its reliably scalable use of waste feedstocks. Using biosolids, a problematic waste, diverts material from landfills but also creates significant value out of what was previously a disposal burden. Many existing biochar and catalytic systems require costly, pure precursors and are limited by supply chain complexity. Here, the biosolids approach enables local, decentralized production at waste management facilities. This makes PYROCO™ suitable for urban, peri-urban, and rural areas where wastewater treatment plants are located.1
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Product Profile: Phenolics and Hydrocarbons
The bio-oil produced by the PAC-enhanced process of PYROCO™ shows significant compositional improvements. It contains more phenolics, which are important for making resins, adhesives, and pharmaceuticals. This increase in phenolics opens up new revenue opportunities for biochar plants, moving them away from traditional fuel markets toward the specialty chemicals sector.1,2
Simultaneously, the hydrocarbons yield increases, enhancing the bio-oil's stability and heating value. The process also reduces nitrogen and carbonyl compounds, improving the overall fuel properties and turning the bio-oil into a valuable chemical feedstock for various industries.1,2
Scalability and Integration with Existing Infrastructure
The PYROCO™ technology shows good potential for scaling up due to its advanced fluidised-bed pyrolysis and gasification design. Successful pilot trials have processed up to 1 ton of biosolids daily. Unlike traditional auger reactors, PYROCO™ provides more even temperature distribution and better heat transfer, which helps improve product consistency and reactor efficiency. The pilot tests produced biochar with around 30 wt% yield and effectively removed contaminants like per- and polyfluoroalkyl substances (PFAS), polycyclic aromatic hydrocarbons (PAHs), pharmaceuticals, and microplastics, indicating it can operate successfully on a larger scale.
Energy analyses suggest that a commercial PYROCO™ plant processing around 10 tons per day could reach thermal energy self-sufficiency when biosolids have more than 30% solids content and a calorific value above 11 MJ/kg.1,2
The integration of PYROCO™ within existing biosolids management systems uses a modular fluidized-bed reactor and gasification units that work together to improve energy recovery and biochar quality. The gas produced in the gasifier acts as the fluidizing medium for the pyrolysis reactor, creating a closed-loop system that increases thermal efficiency and supports steady operation.
Process modeling has shown that this integrated system consistently performs well, maintaining stable gas compositions and energy balances. The flue gas treatment system, which includes venturi scrubbers and activated carbon filters, captures emissions to meet environmental standards, making it safer for use in wastewater treatment facilities.1,2
Techno-economic assessments emphasize that the economic success of scaling PYROCO™ depends on improving biochar sales, feedstock quality, and the operation ratios between the gas producer and pyrolysis reactor.
Adjusting the feed fraction can help strike an optimal balance between biochar production and energy generation. Lower feed ratios tend to boost biochar yield and improve net present value (NPV). Profitability, however, hinges on key factors such as operating expenses and capital costs—biosolid processing, for instance, runs at approximately AUD 205 per ton, aligning closely with costs seen in gasification technologies.
While current biochar prices may constrain profitability, emerging markets—particularly in adsorption and specialty applications—have the potential to enhance returns, positioning PYROCO™ as a practical solution for waste management.1,2
Conclusion
PYROCO™ brings a new direction to the biochar sector by establishing a viable, scalable path from biosolids waste to high-value bio-oil and phenolic chemicals. Its technology design, based on the activation of biosolids-derived biochar, represents a technically sound and resourceful method with broad scalability potential. This approach delivers operational efficiencies, product quality, and cost savings, positioning it as a likely disruptor in the biochar and renewable chemicals market.
References and Further Reading
- Kaur, R. et al. (2025). Role of carbo-catalyst on upgrading the pyrolysis vapors of spent Eucalyptus nicholii biomass: Towards sustainable phenolics production. Renewable Energy, 242, 122468. DOI:10.1016/j.renene.2025.122468. https://www.sciencedirect.com/science/article/pii/S0960148125001302
- Rathnayake, N. et al. (2024). The Pyrolysis of Biosolids in a Novel Closed Coupled Pyrolysis and Gasification Technology: Pilot Plant Trials, Aspen Plus Modelling, and a Techno-Economic Analysis. Water, 16(23), 3399. DOI:10.3390/w16233399. https://www.mdpi.com/2073-4441/16/23/3399
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