From Burden To Valuable Resource: Transforming CO2 Emissions

The chemical processes involved in the production of cement make it one of the world’s most significant sources of carbon dioxide (CO₂) emissions. According to a 2021 report published by Imperial College, every tonne of clinker emits up to around 0.6 tonnes of CO₂ during the calcination process. In fact, the Global Cement and Concrete Association (GCCA) reports that the cement industry contributes around 7 – 8% of global man-made CO₂ emissions. That puts cement ahead of the aviation industry, and beyond the emissions of any individual country, other than China or the US.

Clearly, curbing CO₂ emissions from cement production will make a crucial difference in helping the world achieve its net zero objectives to limit global warming. There are possibilities to make reductions along the value chain, for example by replacing fossil fuels with renewable energy and green hydrogen, developing more energy-efficient kilns, and introducing innovative low-clinker cements. However, these measures cannot eliminate CO₂ emissions completely. This is because a large proportion of CO₂ emissions result from the calcium carbonate (CaCO₃) contained in the clinker, which reacts to form calcium oxide (CaO) and releases CO₂ into the atmosphere. So, there is a significant gap that will have to be addressed by carbon capture and storage (CCS) technology.

The challenge is that CCS is still in its infancy, especially within the cement industry. According to the cement tracking report published by the International Energy Agency (IEA) in September 2022, only around 0.1 megatonne (Mt) of cement emissions are being captured today. That means CCS deployment must increase drastically within this decade, and must be capable of capturing almost 180 Mt in 2030.

Rohrdorfer Zement pioneers carbon capture in Germany

One cement manufacturer that is rising to the CCS challenge is Rohrdorfer Zement which produces high-grade building materials to cover regional demand at sites in Germany, Austria, Italy, and Hungary. The company has already taken a pioneering approach to achieving CO₂-neutral production. For example, it was among the first to use a scrubbed gas catalytic converter for denitrification (removal of NOx – nitrogen oxide and nitrogen dioxide) from kiln emissions and, with the aid of a power station, to convert the waste heat from cement production into electricity.

The Rohrdorf site in Bavaria, Germany has already seen major developments in decarbonisation. In 2022 it was producing cement with 45% less CO₂ than in 1990. This was achieved by optimising cement types and fuel use. The aim is to achieve a reduction of 65% by 2030. The remaining 35% can only be reduced by capture.

Under its own initiative, Rohrdorfer has invested around €3 million in Europe’s first carbon capture facility for the cement industry. This pilot plant has been developed with ANDRITZ as the engineering, procurement, and construction (EPC) contractor. Driven by innovation and technology, ANDRITZ supports sustainable solutions that extend well beyond the scope of carbon capture. The plant, which started operation in the fall of 2022, is now capturing 2 tpd of CO₂, which is being used as a valuable commodity by the chemical industry in the region.

There are two main drivers for Rohrdorfer’s investment in the carbon capture pilot, as Helmut Leibinger, head of the company’s net zero emissions team explains:

“Currently, we enjoy free status under the emission trade system (ETS). That means we have a free allocation of certificates for the carbon dioxide we leak into the atmosphere. But this is being phased out, so it will be prohibitively expensive for this to continue. Our aim therefore, is to find a way to decarbonise our production by 2038. We saw the potential for carbon capture from ANDRITZ’s previous experience in other industries, but we were not yet ready for a full-scale project, especially as we felt that we couldn’t just ‘copy and paste’ from, say, the oil and gas industry. We needed to carry out a proof of concept to verify the technical, qualitative, and economic conditions for CO₂ capture and conversion in the cement industry.”

“Furthermore, our industry needs to start seeing the potential of carbon dioxide as a valuable asset rather than a problem that has to be disposed of. This project is demonstrating how it can be transformed into methanol, ethylene, or formic acid, becoming a starting material for many products that are currently derived from petrochemicals.”

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Read the article online at: https://www.worldcement.com/special-reports/05062023/from-burden-to-valuable-resource-transforming-co2-emissions/