Decarbonising the cement industry06/09/17
HeidelbergCement will utilise CO2 as much as possible (CCU) and store safely (CCS) the remaining unavoidable cement CO2 emissions. With the use of some four billion tonnes yearly, the building material cement is the basis of the vast majority of infrastructures and buildings constructed worldwide. The unique strength and shaping characteristics have been exploited since 1824 when Joseph Aspdin invented the so-called ‘Portland cement’.
By decarbonising limestone (CaCO3 → CaO + CO2) and a downstream sintering process, the intermediate product ‘clinker’ is produced in rotary kilns. By grinding the clinker and adding some other components cement is being created.
As no other building material can ‘feed’ the world in these quantities for its construction needs, the cement industry has a high responsibility to develop products with a CO2-neutral lifecycle.
“More than 60% of HeidelbergCement’s R&D budget is used to reduce the CO2 footprint of our products. We have been able to decrease the CO2 footprint by 24% in last 25 years, by improving energy efficiency, using biomass fuels and by adapting our product mix. In order to achieve a fully decarbonised cement industry, we are now also investing significantly in CCS and CCU technologies,” Jan Theulen, director of alternative resources at HeidelbergCement said.
CCS and CCU, competitors or complementary?
While the debate remains heated as to whether CCS should be further developed for the power sector (as commercially viable and technically proven alternatives exist), this debate is not relevant at all for the cement industry. Even when cement kilns are to operate completely on CO2-neutral fuels, the process-related CO2 emissions remain and are responsible for >60% of the industry’s greenhouse gases. Therefore, the need for CCS for deep decarbonisation of process industries, such as the cement industry, is broadly recognised.
At the same time, it is undisputable that there is currently no economic justification to install CCS-technology at cement plants. Since the EU-ETS-trading scheme for CO2 was established, the CO2 price has never exceeded 20€/tonne and the most ambitious carbon tax schemes are below 30€/tonne CO2. CCS for cement kilns ranges between 80 – 100€/tonne CO2 resulting in doubling the manufacturing costs for cement. None of the cement companies, in a competitive market, can afford to install such measures by themselves.
Theulen continues: “Nevertheless, the cement industry is persistent in further developing CCS. The objective is to reduce the costs (such as energy demand) of carbon capture by developing innovative technologies.
“While CCS is being further developed, we are exploring and deploying various CCU-technologies. From today’s perspective, the upcoming technologies, when fully exploited, could reduce by some 10-20% of the industries’ need for CO2 mitigation. Yet, the difference to CCS is that in some specific cases a positive business case for CCU has been determined.
“Developing CCU applications will definitely increase the knowhow on how to effectively deal with carbon capture and each contribution to climate change, even in the single digit range, is important to cherish.”
The journey to making CCS feasible
CCS, the first generation
HeidelbergCement has been developing a first-of-its-kind cement CCS-infrastructure in Brevik, Norway. The ambition of the Norwegian government to decarbonise the entire country coincides with the HeidelbergCement’s ambition to explore and deploy CCS. After successful trial operations in 2015 and 2016, it was decided in April 2017 by Gassnova, representing the Norwegian government, to support a feasibility study for the full-scale application of CCS at Brevik-plant.
CCS, the second generation
While the amine CC technology is a proven concept, it has the disadvantage that it requires a lot of energy to operate the post-combustion technology of CCS.
Significant cost savings can be achieved if the cement kiln is operated in ‘oxyfuel’ mode. This technology, which is also known in the power sector, can concentrate the CO2 percentage in the flue gas by recirculating part of the flue gas to the burner, while adding pure oxygen to the burner in order to maintain required burning conditions.
The cement industry in Europe, united by the European Cement and Research Academy (ECRA), has done feasibility studies and trials to develop the oxyfuel cement kiln. For the next step, the technology will be demonstrated on industrial scale in the HeidelbergCement plant in Colleferro, Italy.
CCS, the third generation: separating CO2
In order to bring costs of CC further down, technology provider Calix and HeidelbergCement have built a consortium to develop a process-integrated CO2 separation technology.
The EU has awarded the consortium, named LEILAC, with a €12m to fund the development the technology and to demonstrate it at industrial scale at HeidelbergCement’s Lixhe plant in Belgium.
The objective is to separate CO2 released by the limestone inside the kiln, without using additional energy.
Transforming CO2 into valuable products
CO2 for algae-based feed
Extensive R&D work on the growth of micro-algae in three HeidelbergCement sites (Sweden, Turkey and France) has delivered unanimous outcomes: micro-algae show very good growth rates when dispersing the flue gas through the bioreactors and, most importantly, the generated micro-algae meet all the criteria as feed for cattle and aquaculture.
Based on these findings, HeidelbergCement explored the optimal location for commercial deployment of the CO2 mitigating technology. Preparations are now underway to install a large-scale algae-farm in Morocco benefitting from ideal climate conditions, the availability of large non-arable land plots and favourable labour costs.
“This initiative matches perfectly to our sustainability ambitions. Today we already source our electricity from renewable sources, and converting our CO2-rich flue gas into valuable proteins, while using the sun and seawater, emphasises our messages given at COP22 in Marrakesh”, states Tijani El Babor, environmental manager of Ciment du Maroc, part of the HeidelbergCement Group.
CO2 sequestration in mineral products
Another promising route forward is the use of minerals to absorb CO2 and to transfer them in base ingredients for the building sector.
HeidelbergCement has launched a three-year R&D programme with its partners of RWTH Aachen and IASS Potsdam. The whole programme of €3m is being supported by a grant of the German Ministry of Education and Research (BMBF) as the potential for minerals to sequester CO2 requires further exploration.
The research will evaluate the potential of natural minerals such as basalt and olivine, as well as recycled products such as concrete fines to absorb the CO2. Priority is given to investigate the characteristics and, as a result, the market value of the generated products.
HeidelbergCement is taking responsibility in exploring a number of pathways to realise a CO2-neutral lifecycle for its products. CCS as well as CCU are complementary and vital technologies.
The proactive approach of HeidelbergCement in collaborations within the sector and beyond, has resulted in a range of concrete projects paving the way to a carbon neutral industry.
Director Alternative Resources; Global Environmental Sustainability
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