che_february-2025 - 8

Pilot project planned for thermocatalytic ethanol-tobutene
process
I
n December 2024, the Pacific Northwest National
Laboratory (PNNL; Richland, Wash.; www.pnnl.gov)
announced a three-year collaborative project with vehicle-tire
manufacturer Bridgestone (Tokyo, Japan; www.
bridgestone.com) to scale up a thermocatalytic process
for converting renewably derived ethanol to n-butene.
Conventionally, n-butene is produced from petroleumbased
feedstocks using energy-intensive cracking of
large hydrocarbons. The PNNL process, using a catalyst
PNNL researchers first conceived in 2018, could lower
the energy requirements for n-butene production compared
to the conventional process, and allow the use
of renewably derived n-butene as a starting material for
multiple commercial processes, including those for tires
(styrene-butadiene), as well as other synthetic rubbers,
plastics and diesel and jet fuels.
After advancing the catalyst over the past few years,
PNNL partnered with Bridgestone to scale up and pilot
the catalysis process using $10 million in funding from
the U.S. Dept. of Energy's Industrial Efficiency and Decarbonization
Office. Bridgestone plans to build a pilot
plant for the process in Akron, Ohio.
The PNNL catalytic process has shown the ability to
convert ethanol to n-butene at high rates and with high
yields. A highly active, multifunctional catalyst comprising
silica as a support material, with silver nitrate powder and
zirconium nitrate as the catalytic material, enables a sinD
eveloping
sustainable pathways to ethylene -
among the world's most widely used chemicals
- is a key element in decarbonizing the process
industries. A new electrolysis technology developed
by CERT Systems (Toronto, Ont., Canada; www.
co2cert.com) can produce ethylene from CO2 and water,
splitting the CO2 molecule and reforming it into ethylene
using renewable energy (diagram). " Our Direct CO2 Electrolysis
technology is the only single-step process to generate
sustainable ethylene. Other processes to convert
CO2 into ethylene require a separate source of hydrogen
or an intermediate feedstock, such as syngas or ethanol.
Our process only requires CO2 and water as reactants, reducing
complexity and cost, " explains Alex Ip, co-founder
and CEO of CERT Systems. Similar to the production of
" green " hydrogen via water electrolysis, the process depends
on a membrane electrode assembly and an electrocatalyst
to facilitate the ethylene and oxygen evolution
reactions. Unlike most water-electrolysis systems, notes
Ip, CERT's catalysts do not require any precious metals.
CERT's technology is designed to be agnostic to the
source of CO2, meaning that industrial emissions or atmospheric
CO2 can be successfully converted into ethylene.
The process' emissions-processing performance
was first demonstrated in the field at Shepard Energy
Centre natural-gas power plant in Calgary, Alta., Canada.
" This was the first time that industrial emissions had been
converted into ethylene. We were able to convert up to
100 kg of CO2 per day in this project, " says Ip. The company
recently began a research partnership with global
8
gle-step conversion
process
(diagram).
The
catalyst, together
with
the process,
generates nbutene
with
greater than
90% ethanol
conversion and greater than 60% selectivity (byproducts
are predominantly other olefins), PNNL says.
The process works by removing hydrogen from ethanol
molecules, creating acetaldehyde. Formation of carbon-carbon
bonds follows to produce crotonaldehyde,
which occurs in a variety of foods, like soybean oils. The
crotonaldehyde is then converted to crotyl alcohol, which
undergoes dehydration, resulting in butadiene. Butadiene
then is selectively hydrogenated to n-butene. A more
recent catalyst formulation produces n-butene through
butyraldehyde instead of butadiene intermediate, PNNL
says. This new catalyst formulation produces three times
less coke, leading to significantly improved catalyst stability,
PNNL says.
Catalyst regeneration has been demonstrated, the
laboratory adds. The technology is available for licensing.
PNNL
Single-step process for electrified ethylene production
chemicals manufacturer AGC, Inc. (Tokyo, Japan; www.
agc.com) to further develop the technology for commercial
use. " AGC is seeking ways to convert their process
emissions into feedstocks that they currently need to
buy, including ethylene. Our technology can help reduce
their emissions while generating their own feedstocks internally, "
adds Ip.
CERT Systems
The next steps in scaling the technology will be to expand
the system's range of tolerance for different feed
compositions and moving to a commercial-scale pilot
plant following funding. Beyond decarbonizing ethylenebased
processes, the company plans to apply its technology
to other chemical pathways, such as the production
of sustainable aviation fuel (SAF).
CHEMICAL ENGINEERING WWW.CHEMENGONLINE.COM
FEBRUARY 2025
http://www.pnnl.gov http://www.bridgestone.com http://www.agc.com http://www.co2cert.com http://WWW.CHEMENGONLINE.COM
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