Technology Roadmap Low-Carbon Transition in the Cement Industry

Technology Roadmap
Low-Carbon Transition in the Cement Industry
z
A suitably sized market
is needed to run facilities 
at full capacity. Process equipment operating 
at maximum design continuous loads delivers 
maximum energy performance.
z
Local conditions
, such as raw material 
characteristics, clinker composition and 
typical plant size, as well as cement fineness 
requirements, affect the energy required per 
tonne of cement.
z
Other carbon emissions reductions levers
can be correlated with energy efficiency. For 
example, increased use of alternative fuels 
generally increases specific energy consumption 
because of a higher air requirement and moisture 
content. Current technologies are mature 
enough to recover excess heat to serve different 
uses in enhancing energy efficiency. Therefore, 
the overall lower CO
2
emissions through 
increased use of alternative fuels outweigh 
the disadvantage of increased specific energy 
consumption.
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Strengthened environmental requirements
can increase power consumption in some cases 
(e.g. limits on dust emissions require more power 
for dust separation, regardless of the technology 
applied).
Research and development needs 
and goals
There is a range of grinding technologies at the 
research and development (R&D) phase. Their 
applicability and impact on the cement industry 
should be investigated. One example is contact-free 
grinding systems (e.g. vortex technology),
25
which 
could present clear advantages given the limited 
durability of wear elements of current grinding 
systems. The European Cement Research Academy 
has established a research project dedicated to 
efficient grinding in the cement industry. The 
project is precompetitive and involves cross-sectoral 
stakeholders including equipment suppliers (ECRA 
and CSI, 2017).
25. 
Other grinding technologies at the R&D phase include 
ultrasonic comminution, high-voltage power-pulse 
fragmentation and low-temperature comminution.
Further optimisation, taking a holistic approach in 
areas such as particle size distribution and grinding 
aids, could yield energy efficiency benefits.
Switching to alternative fuels
Switching to alternative fuels that are less 
carbon intensive than conventional fuels 
delivers 0.9 GtCO
2
or 12% of the cumulative CO
2
emissions savings by 2050 globally in the 2DS 
compared to the RTS. This is equivalent to 42% 
of current direct CO
2
emissions of global cement 
production.
Coal is the fuel that is most widely used in cement 
production, representing 70% of the global cement 
thermal energy consumption. Oil and natural 
gas jointly contribute 24% to the thermal energy 
demand in global cement production, and biomass 
and waste
26
(alternative fuels) contribute just above 
5% of the global thermal energy use in the sector. 
Switching to fuels that are less carbon intensive 
enables a reduction of 24% globally by 2050 in 
the share of fossil fuels in the 2DS (Figure 10). 
This results in the reduction of the CO
2
intensity 
of the global cement thermal energy demand 
from 0.088 tonne of carbon dioxide per gigajoule 
(tCO
2
/ GJ) to 0.058 tCO
2
/GJ over that period, 
equivalent to 0.9 gigatonne (Gt) of cumulative CO
2
savings in the 2DS compared to the RTS.
26. 
Waste includes biogenic and non-biogenic waste sources. 
Biomass and biogenic fractions of waste are considered 
neutral in terms of CO
2
emissions generation from 
combustion.

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4. Carbon emissions reduction levers
Material efficiency strategies, such as reuse of 
consumer goods and products that are less material 
intensive in a low-carbon society, affect the type 
and amount of waste materials available in the 
future. Typical wastes that can be used as alternative 
fuels in cement kilns include the following, some of 
which are totally or partially biogenic in nature:
z
discarded or shredded tyres.
z
waste oils and solvents.
z
pre-processed or raw industrial waste, including 
lime sludge from paper and similar industries.
z
non-recyclable plastics, textiles and paper 
residues.
z
fuels derived from municipal solid waste.
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effluent treatment sludge from water and 
wastewater treatment plants.
Fuels that are based entirely on biomass in the 
cement industry include waste wood, sawdust 
and sewage sludge. The use of other biomass-
based matter from fast-growing cultivated species 
(e.g. certain wood, grass and algae) is possible from 
a technology perspective, but it is not currently 
globally economical for the cement industry. There 
are technical requirements that should be satisfied, 
for example, a high minimum average calorific value 
of 20-22 GJ/t fuel in the firing of the kiln compared 
to levels provided by typical organic materials 
(10-18 GJ/t).
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Precalciner kilns can integrate up to 
60% of fuels with a low calorific content, as the 
precalciner operates at a lower process temperature 
(ECRA and CSI, 2017). 
In low-carbon contexts such as the 2DS, where 
end-users increasingly compete for biomass energy 
sources to support carbon emissions reductions 
strategies, the price of biomass is likely to increase. 
The 2DS considers that a maximum of 140 EJ of 
biomass feedstock can be sustainably supplied 
globally by 2050 (IEA, 2017). The flexibility of 
cement kilns to operate with a wide range of fuels 
without requiring major equipment refurbishment 
makes them cost-effective biomass users in a 
carbon-constrained world compared to industrial 
manufacturing processes based on a single fuel. 
Cement production absorbs about 7% of the 
biomass-related final energy demand of the overall 
industrial sector globally by 2050 in the 2DS.
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27. Calorific values are provided in net terms, considering losses for 
evaporation of contained water.
28. Biomass use reported here does not include biomass demand 
for onsite power generation units in the industrial sector.