Engineering, procurement, and fabrication for a pilot-scale hydrothermal liquefaction plant

Purpose

Battelle as operator of Pacific Northwest National Laboratory (PNNL) is requesting information from companies with demonstrated engineering, procurement, and fabrication experience of biomass processing and conversion plants (or hydrothermal processing technologies) with specific interest in hydrothermal liquefaction plants.

The information gained from this RFI will identify companies with the interest and experience to successfully design and fabricate a pilot scale hydrothermal liquefaction (HTL) pilot plant capable of processing biomass at a scale of 0.5 dry tons per day (dtpd) based on Battelle’s internal concept. The primary purpose of the HTL pilot plant will be to demonstrate successful, uninterrupted operation for 500 consecutive hours producing approximately 1 barrel per day of biocrude product.

Background

HTL has the potential to be a nexus between diverse organic waste management and biofuels production. HTL is well suited for conversion of high moisture organic materials, such as municipal wastewater sludges, algae, food waste, manures, and other agricultural wastes into biocrude oil. The resulting biocrude is suitable for refining into renewable liquid fuels, including synthetic aviation fuel, marine fuel, and renewable diesel.

The principles of the HTL process were first outlined over a century ago. While conceptually straightforward, the development of HTL technology at pilot and commercial scales has been limited. HTL involves the use of hot, near-critical, compressed water (373.9 °C and 220.6 bar) as both a solvent and reactant to convert biomass into biocrude. During this process, a series of reactions take place, enabling the breakdown of polymeric substances within biomass into a water-insoluble biocrude, alongside water-soluble compounds in an aqueous phase, gases, and solid residues.

Interest in the HTL process surged during the crude oil crises of the 1970s and 1980s, prompting significant research and development efforts. Key contributions came from research institutions like PNNL, Lawrence Berkeley National Laboratory, and the Pittsburgh Energy Research Center. Presently, there are limited examples of subcritical HTL pilot, demonstration, or commercial scale systems in North America, a HTL demonstration plant is under construction at Metro Vancouver Annacis Island Wastewater Treatment Plant in Delta (Canada) while in Europe, Circlia Nordic is offering small scale HTL systems (up to 15 dtpd) for commercial purchase.

Despite its promising results, HTL technology has yet to see widespread adoption. Comprehensive performance evaluations and detailed engineering studies are needed to guide industrial-scale implementation. Further pilot and demonstration projects are critical to attracting stakeholders for the necessary investment for the construction of commercial-scale plants. Battelle has interest in housing the largest hydrothermal liquefaction process research facility in the U.S. to implement develop and prove technology at relevant scale.

Through DOE support, Battelle has carried out research to advance the technical readiness of HTL including operation of an engineering-scale modular process development unit (PDU) capable of processing approximately 50 kg (dry basis) of biomass per day.  To further develop the technology, Battelle is redesigning the PNNL HTL PDU to enhance process reliability, reduce downtime, maintain product quality, and increase operator safety. The redesign will target a feed throughput of approximately 0.5 dtpd, resulting in approximately one barrel per day of biocrude production.