Page 169 - CW E-Magazine (4-6-2024)

Special Report

from fossil sources – oil, natural gas global temperature increase to well be- and methanol. In recent years, natural
and coal. Feedstocks are transformed, low 2°C. There are also chemicals-spe- gas derived feedstocks have become
often at high temperature and pressure, cific sustainability strategies, as well as much more significant for ethene and
into the key ‘primary chemicals’ used industry initiatives to reduce emissions propene production, due to the rise in
to service the chemical industry. in response to legislation and consumer shale gas production in, for example,
expectations. The chemical sector will the US.
In this report, primary chemicals be able to reduce Scope 1 emissions
are defined as ethene (C H ), propene through energy efficiency improve- Whilst ammonia is also considered
2
4
(C H ), butadiene (C H ), benzene ments and by decarbonising energy- a primary chemical, it is not addressed
3
6
4
6
(C H ), toluene (C H CH ), mixed intensive processes, such as through in this report, as it is not a carbon-based
6
6
5
3
6
xylenes ((CH ) C H ), and methanol electrification and the use of green hy- chemical and was recently the subject
4
6
3 2
(CH OH). These primary chemicals are drogen. However, this will not address of a Royal Society report. It is impor-
3
transformed by a wide range of pro- the chemical sector’s significant Scope tant to note that ammonia is one of the
cesses and chemical reactions into inter- 3 emissions associated with the extrac- largest drivers of chemical sector emis-
mediates, speciality and fine chemicals tion, processing and transportation of sions, accounting for almost 2% of
used to make consumer products. See fossil feedstocks, as well the end-of-life global CO emissions.
2
Figure 1 for a simplified example of the emissions if downstream products are
route from fossil feedstocks to consumer incinerated. To address this proportion The vast range of final products cur-
products. See Figure 2 for examples of emissions, the chemical sector will rently rely on these primary chemicals.
of uses of chemicals found in common have to transition to alternative sources Collectively, primary chemicals account
consumer products. of carbon that do not involve the extrac- for two-thirds of the global energy
tion of fossil resources. demand of the chemical sector and
The chemical sector is responsible underpin many thousands of chemical
for approximately 6% of global CO - This policy briefing explores the products. However, the future chemi-
2
equivalent emissions. These can be cate- feasibility and availability of three cal industry does not necessarily have
gorised into Scope 1, Scope 2 and Scope alternative sources of carbon: biomass, to follow this linear structure domi-
3 emissions. Estimates of chemical sec- plastic waste and CO . The briefing nated by primary chemicals. Biomass
2
tor Scope 3 emissions (see Box 1) range also considers opportunities for novel and plastic waste carbon feedstocks
from approximately just over one-third processes to produce chemical products could generate new or different pri-
to two-thirds of total emissions. This from alternative carbon sources. mary chemicals than those used today,
briefing will use a conservative estimate though may also offer opportunities to
of Scope 3 being responsible for approxi- Overview of current key chemicals bypass primary chemicals and develop
mately one-third of total emissions. and their production process new pathways more directly to fine or
speciality chemicals. Other feedstocks
Chemical sector emissions are being Currently, around 90% of the feed- that are important for the chemical in-
addressed through both voluntary stocks for the chemical industry origi- dustry include water, oxygen, nitrogen,
and regulatory means. More than 70 nate from fossil sources, specifically, hydrogen, and the halogens (chlorine,
countries plus the EU have set targets in oil, natural gas and coal. Oil can be pro- bromine and iodine), although these are
legislation or policy to achieve net zero cessed for ethene, propene, benzene, not the focus of this briefing.
emissions, whilst 194 countries have toluene and mixed xylenes. Natural gas
signed the Paris Agreement to limit and coal are used to produce ammonia A broad overview of how fossil
Box 1: Scope definitions
Scope 1: direct emissions associated with the processes involved in making the carbon-based chemical. This includes
emissions related to the combustion of fossil fuels to produce energy, as well as direct process emissions.

Scope 2: upstream indirect emissions associated with purchased electricity for chemical conversion processes.

Scope 3: indirect emissions associated with upstream and downstream processes. Upstream processes include the extrac-
tion and production of feedstocks. Downstream processes include product use and end-of-life disposal, such as degrada-
tion and incineration.

Chemical Weekly June 4, 2024 169

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