Page 173 - CW E-Magazine (18-6-2024)

Special Report

combining it with other chemicals. This access to sufficient low-cost renew- tolerance to water, which is a common
utilisation does not rely on any hydro- able energy and other resources such as by-product of these reductions. There
gen or reductant and can be economi- water, and changes in the policy and is a major effort to transform CO into
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cally attractive since the CO replaces funding landscape. DAC currently higher alcohols directly, avoiding the
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petrochemicals. For example, CO co- costs around US$200-600 per tonne of need for methanol as an intermediary.
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polymerisation with epoxides produces CO removed. This would have to fall Such chemistry could be advantageous
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polycarbonate polyols used to make to make large scale chemical production as a direct route to high-value surfac-
insulation foams, coatings, sealants, from DAC CO competitive. There will tants, lubricants and intermediates in
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adhesives and elastomers. This techno- also be competing demands for CO in the chemical industry.
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logy is therefore advanced as a CO other sectors, such as for concrete and
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utilisation. CO can also be reacted with building materials. There is also growing The copolymerisation of CO with
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epoxides to produce cyclic carbonates, interest in the use of DAC CO for syn- other monomers continues to focus on
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essential electrolytes for batteries and thetic fuels for transportation, for heating diversifying the range of polymers pro-
electric vehicles. and, to a less extent, in the power sector. duced, increasing catalytic activity and
selectivity, and designing processes
Availability of CO 2 There are various future estimates that are accelerated by common impu-
There is currently a high potential of how much CO the chemicals sec- rities, such as water.
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availability of CO from point sources, tor could utilise, given this competing
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due to the number of large industrial and demand. Lower end estimates suggest More generally, catalytic chemistry
power plants using fossil fuels or bio- 0.2-0.6 Gt CO could be used to pro- that functions using mixtures or inhomo-
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ethanol. Industrial point sources could duce polymers and other chemical geneous supplies of raw materials,
meet demand for chemical sector CO products. Higher end estimates propose including CO , is an active research
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use in 2030, but would likely not suffice that the chemical industry may require field. Carboxylation chemistry also
by 2050, as point sources of CO decline as much as between 2.8-Gt up to 4.7-Gt provides routes, independent of hydro-
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in the context of net zero ambitions and in 2050. It is difficult to estimate exact gen, to produce carboxylic acids, esters
demand across other sectors increases. It supply and demand, given the infancy and carbonates which are useful as both
is further necessary to consider how the of some technological routes, overcom- monomers but also products in their
choice of CO source affects the climate ing the energy requirements to turn CO own right. Electrocatalysis offers another
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impact, eliminating some sources for into reduced carbon molecules and the interesting opportunity to create pro-
select product categories. To meet the changing policy landscape. It is also ducts from CO , with a significant
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growing demand for CO , DAC supply important to note that the estimates of research effort into ethene, ethanol
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would have to expand significantly. At the overall scale of CO utilisation for and propanol production.
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present, DAC plants capture approxi- chemicals is less than 1% of annual
mately 0.01-mt CO per year. Plants anthropogenic input of CO into the These processes typically depend
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under construction or in advanced atmosphere (~59-Gt CO equivalent). on copper catalysts. There is on-going
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development will likely only be able to research focusing on innovative reac-
capture around 4.7-mt CO per year by Future challenges of CO to chemicals tors, flow engineering, improving carbon
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the end of this decade. Under the Inter- As discussed, the production of mass balance, improving catalyst life-
national Energy Agency’s Net Zero chemicals from CO is feasible at a limi- time and tolerance to impurities, as well
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by 2050 scenario, DAC expands to just ted scale but requires enormous quanti- as integrating the reductive chemistry
under 1-Gt CO by 2050. ties of green hydrogen and renewable with other chemical oxidations.
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power. The production of ethene and
At present, approximately 0.2-Gt other hydrocarbons needs more deve- Photochemical and photoelectro-
of CO is used globally each year, of lopment, including in catalysis, means chemical CO conversions are at a
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which around half is used to produce of driving processes (heat or electricity), much earlier technical stage, with re-
urea fertiliser and around a third is used process and reactor design and cou- search needed to identify the most
for the extraction of crude oil through pling with other chemical manufactur- promising photoactive materials, cata-
enhanced oil recovery. To achieve ing. For thermochemical catalysis, the lysts and to prevent decay processes.
a significant scale up of CCU, there focus has been on reducing the tempera- The production of prototype devices
would have to be developments in both ture for the reduction pathways, driv- and engineering of the materials inter-
capture and utilisation technologies, ing selectivity higher and improving faces is also an important current and
Chemical Weekly June 18, 2024 173
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