Thermochemical Conversion to Biocrude

Introduction

Thermochemical conversion refers to processes that use heat and chemical reactions to transform biomass into fuel-like products. One such product is biocrude—a thick, viscous, petroleum-like liquid that can be refined into biofuels, chemicals, and lubricants.

This route mimics fossil fuel formation but compresses it into minutes or hours instead of millions of years. It’s ideal for wet, lignocellulosic, and residual biomass where biological routes (like fermentation) are inefficient. Thermochemical processes such as hydrothermal liquefaction (HTL) and pyrolysis are leading the way in converting waste into drop-in bio-oils for existing petroleum infrastructure.

What Products Are Produced?

Thermochemical conversion of biomass primarily yields:

• Biocrude oil (via HTL or pyrolysis): Can be upgraded to diesel, jet fuel, and gasoline
• Biochar: Soil amendment, carbon sink, or industrial adsorbent
• Syngas: CO and H₂ for power, hydrogen production, or Fischer–Tropsch fuels
• Aqueous phase organics: For nutrient recovery or chemical extraction
• Light gases: CH₄, CO₂, useful for internal energy recovery

Pathways and Conversion Methods

1. Hydrothermal Liquefaction (HTL)
• Biomass is treated at 280–370°C under high pressure (10–25 MPa) in water to produce biocrude, gas, and aqueous phase.
• Works especially well with wet biomass (e.g., algae, food waste, sewage sludge).
2. Fast Pyrolysis
• Biomass is rapidly heated to 450–550°C in the absence of oxygen.
• Produces bio-oil, char, and gas in seconds; needs dry feedstock.
3. Catalytic Thermolysis
• Enhances HTL with in-situ catalysts for improved biocrude quality.
4. Microwave-Assisted Conversion
• Emerging process using electromagnetic heating for uniform, energy-efficient conversion.

Catalysts and Key Tools Used

• Catalysts: Alkali salts (K₂CO₃, NaOH), transition metals (Ni, Co, Mo), zeolites
• Reactors: Continuous-flow HTL, bubbling fluidized-bed pyrolysis, microwave reactors
• Pretreatment Tools: Dryers, size reducers, slurry pumps
• Upgrading Units: Hydrodeoxygenation (HDO), distillation, hydrotreaters for refining crude
• Analytics: GC-MS, FTIR, calorimetry for product profiling

Case Study: Shell + IH2® Technology by GTI

Highlights

• Shell and Gas Technology Institute (GTI) partnered to scale IH2®—a catalytic thermochemical process converting biomass to drop-in biofuels.
• Converts lignocellulosic waste into gasoline and diesel-range hydrocarbons without external hydrogen.
• Modular design allows decentralized deployment in rural or industrial settings.

Timeline

• 2011 – IH2® developed by GTI
• 2014 – Pilot plant in Bangalore with Indian biomass feedstock
• 2017 – Shell joins to scale and test integration with refineries
• 2022 – Commercial licensing and demonstration-scale plants in USA and India

Global and Indian Startups Working in This Area

Global

• Steeper Energy (Denmark/Canada) – Hydrothermal liquefaction of forestry and municipal waste
• Envergent Technologies (USA) – Fast pyrolysis-based bio-oil systems
• Licella (Australia) – Catalytic hydrothermal reactors for plastic and biomass liquefaction
• Anellotech (USA) – Catalytic pyrolysis to produce BTX aromatics and biocrude

India

• Thermax & CSIR-IIP (Dehradun) – Joint development of HTL systems for sewage and sludge
• Vayujal (Pune) – Mobile pyrolysis units for agricultural and food waste
• Altret Greenfuels (Gujarat) – Developing continuous pyrolysis-based biocrude for industrial boilers
• IIT Madras & IISc – Research and pilot units on algae-based HTL and decentralized pyrolysis

Market and Demand

The global biocrude market is valued at USD 1.8 billion in 2023 and is projected to reach USD 5.3 billion by 2030, growing at a CAGR of ~16%, driven by demand for decarbonized fuels and waste-to-energy technologies.

Major End-Use Segments:

• Transportation fuels – Diesel, marine fuels, SAF (after upgrading)
• Power generation – Co-firing with coal or direct combustion
• Industrial heating – Boilers and furnaces using raw or blended bio-oil
• Chemical intermediates – Phenols, aromatics, resins

Key Growth Drivers

• Abundant biomass waste in agriculture and municipalities
• Compatibility with existing refineries via upgrading
• Global SAF mandates and diesel blend targets
• Decentralized energy needs in off-grid or rural zones
• Growing policy incentives for low-carbon intensity fuels

Challenges to Address

• High oxygen content in raw biocrude leads to instability and corrosiveness
• Complex upgrading steps needed before use in engines or turbines
• Feedstock variability affects consistency in fuel properties
• Water content and phase separation in HTL bio-oils
• CAPEX-intensive for modular plants with pressure and temperature controls

Progress Indicators

• 2012 – First continuous HTL units demonstrated
• 2014 – Pilot projects in India for sewage-to-oil
• 2018 – Steeper Energy licenses biocrude upgrading to oil refineries
• 2021 – Bio-oil tested as marine fuel blendstock (IMO decarbonization)
• 2023 – Indian government announces funding for thermochemical SAF pilots

HTL and pyrolysis for biocrude production are at TRL 7–8; upgrading to SAF and diesel is at TRL 6–7, with modular and integrated systems progressing steadily.

Conclusion

Thermochemical conversion to biocrude is a powerful solution to turn low-value waste into high-value renewable oil. As decarbonization of heavy transport and industry accelerates, biocrude can serve as a drop-in, scalable, and decentralized replacement for fossil fuels.

India’s biomass potential, research institutions, and refinery infrastructure make it a promising hub for thermochemical biocrude innovations—positioning the country to lead in both waste management and clean energy simultaneously.

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