Page 186 - CW E-Magazine (11-6-2024)

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In contrast, the production of con- and economic implications of a less tive agricultural land is used for food or year. Using the assumption from the ing the use of biomass as a chemical chemicals is processing lignocellulose.
ventional building blocks with no oxy- integrated value chain. This ambition biomass crop cultivation, future global International Energy Agency of 100 EJ feedstock. As discussed, one of the main This is heterogeneous in its structure
gen atoms, such as ethene, from bio- requires the development of novel population and dietary change, demand per year, this equates to just over 7 Gt issues to a bio-based carbon industry is and weight distribution, making it dif-
mass is energy intensive as it requires chemical transformations with the poten- for biofuels, and the protection of land of biomass, including moisture content. that sources of biomass are limited and fi cult to process. As a result, lignocellu-
its deoxygenation. This could encour- tial of having fewer processing steps for nature. Biomass availability will there is competition for these raw ma- lose is often discarded as waste product
age the production of novel chemical and lower energy demands than cur- differ between countries and regions, However, there are many potential terials from other sectors, mainly for or burned for heating and power gene-
building blocks from biomass that are rent ones. A potential example of this is due to a range of factors including geo- uses for biomass, with competing sec- bioenergy but also increasingly in other ration, leading to the loss of a potential
closer to the fi nal products – bypassing shown in Box 2. graphy and domestic policy. toral demands, such as for food, ani- sectors, such as for aviation fuels. To biomass source for chemicals produc-
the existing dominant primary chemi- mal feed and bioenergy. For example, maximise value from potentially limi- tion or other uses. Research and inno-
cals. This may theoretically mean the Biomass availability Approximately 60 EJ (exajoules) global food production may have to ted resources, the priority for research vation that helps make the processing
future chemical industry manufactures There are many complex, inter- of solid bioenergy (energy generated increase by more than 50% by 2050 to could be on new or specialist chemi- of lignocellulose easier could unlock
many more fi nal products, rather than acting factors that will infl uence the from biomass) is used per year glo- meet demands for a growing popula- cals in high margin applications such as the economic value of this hugely
deriving the majority of products from future availability of biomass. These bally. This is equivalent to around 4.3 Gt tion, whilst demand for bioenergy has food, health and well-being products or underutilised resource for making higher
just a few primary chemical building include improvements in crop yields of fresh biomass. Under future net zero risen by 3% per year since 2010 and is cosmetics. However, due to their small value chemicals.
blocks. (itself connected to the production of scenarios, which account for food sup- forecast to continue increasing. There is scale in comparison to primary chemi-
energy-intensive fertilisers), the impact ply and environmental considerations, also increasing demand for biomass for cals production, this would not make a The diverse spatial distribution of
Further research is required to bet- of climate change on agricultural pro- estimates of the future bioenergy sup- Sustainable Aviation Fuels (SAF) (see signifi cant contribution to the overall biomass sources could also pose logis-
ter understand any potential technical ductivity, the extent to which produc- ply required range from 85-250 EJ per Case Study 1). net zero transition. tical transportation or cost challenges
for chemical producers. Collaboration
Considering the above competing Furthermore, biomass has a highly on effi cient process design and tech-
Box 2: Biomass to levulinic acid demands and wider sustainability con- heterogeneous nature. Generally, chemi- nology sharing could help the sector to
siderations, it is unlikely that existing cal processes are diffi cult to adapt to avoid some of these issues, whilst there
Levulinic acid is seen as an attractive ‘steppingstone’ chemical building block that can be made from waste biomass. sources of biomass will provide a signi- variable feedstocks as the industry has could also be greater opportunities for
Possessing two different reactive functional groups – ketone and carboxylic acid – levulinic acid is highly versatile for fi cant percentage of embedded carbon been built largely on the use of uni- smaller, integrated biorefi neries. The
the synthesis of a large number of downstream intermediate chemicals63, which are used in many industries including required by the chemical industry under form and consistent raw materials. This use of more novel forms of biomass,
polymers, electronics, cosmetics, solvents and fuels. expected growth trajectories. Biomass could cause issues for businesses if such as seaweed and algae, is still at the
may, though, act as a promising route there is a signifi cant number of highly research phase.
Levulinic acid synthesis has been studied extensively in academia, using a wide range of biomass sources, such as food for more limited markets, such as for bespoke processes for converting dif-
crops, food waste and even algal biomass. In particular, levulinic acid can be derived from fi ve- and six-carbon sugars, speciality chemicals. ferent biomass types to chemicals and There is a need to develop pre-treat-
such as xylose and glucose found in lignocellulosic biomass feedstocks, including waste wood. downstream products. ment technologies, including physical
Challenges and future research (which are energy-intensive and require
Levulinic acid is now being commercially produced from biomass, principally as a solvent rather than as an intermediate. needs One of the most diffi cult and press- specialised equipment) and/or chemical
Reducing the cost and energy intensity of this potentially important intermediate is the next challenge, to move beyond There are several challenges to scal- ing challenges of converting biomass to (requiring the use of chemicals) methods
very small-scale production and to lower associated emissions.
Case Study 1: Sustainable Aviation Fuels (SAF) biomass demand in the UK
The downstream conversion of levulinic acid to other chemicals has attracted attention from electrochemical investigation
to improve effi ciencies. The UK Government has placed a strong emphasis on the use of biomass for sustainable aviation fuels. The UK has an
upcoming SAF mandate, “requiring at least 10% (c.1.2-mt) of jet fuel to be made from sustainable sources by 2030.” At
To make any substantial impact on the emissions of the global chemical industry, routes from alternative carbon sources present, only a very small fraction of biofuel is used in the UK aviation sector.
will have to be made as low emission as possible and replace high emission pathways at signifi cant scale.
However, a previous Royal Society report has outlined the challenges of meeting the UK’s SAF demand through biomass.
Biomass to levulinic acid route The report outlines three energy crop scenarios – for oil seed rape, miscanthus and poplar – in which more than 50% of
all UK agricultural land would be needed to produce the necessary amount of biomass to replace all the UK’s aviation
fuel. Alternatively, waste cooking oil, agricultural residues, forest residues and municipal waste could account for
approximately 20% of jet fuel demand.
Monosaccharide
Polysaccharide Downstream
Biomass Pretreatment (carbohydrates) (eg xylose and Levulinic acid Alongside land use challenges associated with SAF from biomass, the emissions from the production methods and burn-
glucose) chemicals
ing SAF at altitude should be considered. Whilst biomass for both chemical feedstocks and SAF used in the UK could be
sourced from international markets, the above example is to illustrate the potential implications of replacing fossil sources
with biomass at signifi cant scales.

186 Chemical Weekly June 11, 2024 Chemical Weekly June 11, 2024 187

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