Page 174 - CW E-Magazine (18-6-2024)

Special Report

future research field. Further research native carbon sources and fossil feed- distributed approach to manufacturing.
is required to lower the energy require- stocks do exist, it is important to note Whilst this is not in the scope of this
ments and improve the efficiency of that it is not possible to predict the report and requires further investiga-
DAC technologies, as well as around exact future mix of chemical feed- tion, challenges include a loss of eco-
diversifying and scaling the range of stocks. This will change over time as nomy of scale and heat integration,
products possible from CO . For exam- technologies develop, countries make with subsequent impacts on cost and
2
ple, there is significant potential to use policy and regulatory changes, and energy efficiency.
CO in polymers to toughen structures individual businesses make varying
2
and make them more resilient. Further investment decisions. The mix of chemi- Wider sustainability considerations
research and investment could focus cal feedstocks will also change between and Life Cycle Assessment
on the conversion of CO to syngas for places for similar reasons, as well as the It is critical that any alternative carbon
2
onward conversion to fuels and inter- differing geographies and availabilities sources for chemicals are assessed
mediate chemicals, the conversion of of feedstocks between countries. for their sustainability, to ensure that
CO to oxygenated chemicals, and the they do not have unintended or addi-
2
reduction of CO to alcohols. To replace all fossil carbon in chemi- tional impacts on the environment and
2
cals, it is likely that a combination of society. To classify a carbon source
Emerging routes from CO to chemicals biomass, waste and CO sources will as ‘green’ and ensure that greenhouse
2
2
The role of green methanol as a be required – and that this mix will gas emissions are not reduced at the
building block might become more vary over time. Whilst this may help to expense of other impacts, issues such
prominent in a transition away from reduce supply chain risks through as resource depletion, acidification,
fossil feedstocks. Green methanol can diversification, and potentially help eco- and human toxicity, land use,
be produced via thermal CO conver- reduce sustainability risks of overcon- biodiversity and energy requirements
2
sion using green hydrogen, which is a suming one particular feedstock type, it should all be evaluated. The energy
well-established route. Green methanol will introduce far greater heterogeneity requirements and initial source of
could also potentially be produced into the chemical industry supply chain carbon for all alternative feedstocks
from the biochemical transformation of than exists today. must be critically assessed to ensure
biomass, though these technologies are that both climatic and wider environ-
not yet at commercial readiness level. However, there is also an opportu- mental implications are not worsened.
nity to use alternative carbon sources to Accounting for claims of ‘carbon neu-
New chemical transformations, bypass the existing primary chemicals trality’ or ‘net negative emissions’
such as the recently developed metha- stage straight to downstream, higher need to be considered and documented
nol-to-olefins and methanol-to-aro- value or speciality chemicals. Advances carefully, to avoid risks of greenwashing
matics processes, are alternate ways in industrial biotechnology might open or overstating the benefits of one feed-
of producing olefins and aromatics. It the door to biomanufacturing routes of stock type over another. Addressing
is important to note that these techno- alternative chemical ‘building-blocks’ further social impacts, such as on food
logies have been developed in the context such as acetone, alcohols such as security, are also critical to ensure that
of using coal-based methanol as input, butanol and isopropanol (in addition any transition away from fossil feed-
which results in higher overall emissions to methanol) or directly to high value stocks in chemicals does not have wider
than using naphtha or natural gas as feed- chemicals from biomass, plastics and implications on society.
stocks, but emissions would be lower if CO . As discussed, biomass routes are
2
using green methanol. Further work is difficult to scale to commodity levels Life Cycle Assessment (LCA) is
required to enhance the technology to and may be more effective at more one approach that can be used to assess
commercialisation standard. limited scales for speciality chemi- the impacts of the acquisition, process-
cals – which subsequently impacts the ing, transport, use stage and end-of life
Further considerations for alternative emissions reductions potential. of different feedstocks. However, com-
feedstocks parability between LCA studies is often
Transitioning away from fossil feed- difficult, due to varying assumptions
Future feedstock mix of the chemical stocks may require some businesses and system boundaries used. Further
industry to operate in a less centralised struc- research in this area to better under-
While exploratory estimates of the ture with more modularity, as distri- stand the life cycle and sustainability
potential future mix of each of the alter- buted feedstocks and energy requires a of different carbon sources could sub-

174 Chemical Weekly June 18, 2024

Contents Index to Advertisers Index to Products Advertised