The new Pacific Northwest National Laboratory (PNNL) patented catalyst converts biofuel (ethanol) directly into n-butene, a versatile ‘platform’ chemical. A microchannel reactor design is said to further reduce costs while delivering a scalable modular processing system.
Currently, n-butene is produced from fossil-based feedstocks using the energy-intensive cracking of large molecules. The new technology reduces emissions of carbon dioxide by using renewable or recycled carbon feedstocks. Using sustainably derived n-butene as a starting point, existing processes can further refine the chemical for multiple commercial uses, including diesel and jet fuels, and industrial lubricants.
“Biomass is a challenging source of renewable energy because of its high cost. Additionally, the scale of biomass drives the need for smaller, distributed processing plants,” said Vanessa Dagle, co-primary investigator of the initial research study, which was published in ACS Catalysis. “We have reduced the complexity and improved efficiency of the process, while simultaneously reducing capital costs. Once modular, scaled processing has been demonstrated, this approach offers a realistic option for localised, distributed energy production.”
PNNL is now partnering with Oregon State University (OSU) to integrate the patented chemical conversion process into microchannel reactors built using 3D printing technology, which allowed the team to create a pleated honeycomb of mini-reactors that increase the effective surface-area-to-volume ratio available for the reaction.
“The ability to use new multi-material additive manufacturing technologies to combine the manufacturing of microchannels with high-surface-area catalyst supports in one process step, has the potential to significantly reduce the costs of these reactors,” said OSU lead researcher Brian Paul. “We are excited to be partners with PNNL and LanzaTech in this endeavour."
“Due to recent advances in microchannel manufacturing methods and associated cost reductions, we believe the time is right to adapt this technology toward new commercial bioconversion applications,” said Robert Dagle, co-primary investigator of the research.
The microchannel technology would allow commercial-scale bioreactors to be built near agricultural centres where most biomass is produced. One of the biggest impediments to using biomass for fuel is the need to transport it long distances to large, centralised production plants.
“The modular design reduces the amount of time and risk necessary to deploy a reactor,” Dagle said in a statement. “Modules could be added over time as demand grows. We call this scale up by numbering up.”
The one-fourth commercial-scale test reactor will be produced by 3D printing using methods developed in partnership with OSU and will be operated on the Richland, Washington campus of PNNL.
Once the test reactor is completed, PNNL commercial partner LanzaTech will supply ethanol to feed the process. LanzaTech’s patented process converts carbon-rich wastes and residues produced by industries, such as steel manufacturing, oil refining and chemical production, as well as gases generated by gasification of forestry and agricultural residues and municipal waste into ethanol.
According to PNNL, the test reactor will consume ethanol equivalent to up to one-half dry ton biomass per day. LanzaTech has scaled up the first generation of PNNL technology for jet fuel production from ethanol and formed a new company, LanzaJet, to commercialise LanzaJet Alcohol-to-Jet. The current project represents the next step in streamlining that process while providing additional product streams from n-butene.