Analytical solutions for the safe and efficient CO₂ storage in the cement industry

Analytical solutions for the safe and efficient CO₂ storage in the cement industry

If the cement industry were a country, it would come after China and the U.S. in terms of CO₂ emissions. Or to put it in figures: With a global production volume of 4.5 billion tons of cement per year, the cement industry emits around 2.8 billion tons of CO₂, accounting for around 8% of total greenhouse gas emissions worldwide.¹

These CO₂ emissions, which are generated during cement production, cannot be avoided in principle, as they are based on a natural chemical reaction of the raw material and fuel emissions: The raw material limestone is converted into clinker at temperatures of up to 1,500 °C (calcination process), releasing large quantities of CO₂.

Restricting the cement industry itself is also not realistic; after all, cement is necessary as a binder for concrete wherever construction is taking place. Even projects to promote climate protection, such as the construction of rail lines, energy-efficient buildings, etc., cannot do without cement as an important building material.

There are some approaches to reduction, such as the use of waste heat, a reduction in the proportion of clinker, new manufacturing processes, the use of substitute fuels and recycling of concrete. However, these are not sufficient to achieve climate neutrality.

CO₂ capture and storage for a climate-neutral cement industry

A promising alternative is to filter CO₂ out of exhaust gases before releasing it into the atmosphere. Captured CO₂ can then either be stored, e.g., in rock or in the seabed (CCS - carbon capture and storage), or captured, transported, and further utilized, e.g., as a raw material to produce polymers, fuels and building materials (CCU – carbon capture and utilization). Thus, once captured, the CO₂ can be transported and either stored or reused as a raw material for the production of polymers, fuels and construction materials.

The following carbon capture concepts are therefore considered an important approach:

Carbon capture and storage (CCS)

For this, CO₂ is captured, processed, compressed, and transported to a storage site, e.g., underground (rock or seabed). CO₂ can be captured either from the atmosphere or directly from emission sources during fossil fuel use in industrial processes or power generation.

Carbon capture and utilization (CCU)

CO₂ is captured, transported, and reused, e.g., as a raw material to produce polymers, fuels, or construction materials.

Carbon capture, storage, and utilization (CCUS)

This approach encompasses all variants of CCU and CCS. CCUS allows the high CO₂ concentrations generated by industrial activities to be captured and used effectively. This method therefore has a key role to play in decarbonization.

The potential of carbon capturing

By using these approaches to capture carbon at various stages of the cement manufacturing process, cement manufacturers can significantly reduce their emissions. Each of these processes has its advantages in terms of cost, feasibility, and efficiency.

Pre-combustion capture

involves capturing of CO₂ before it is released during the cement production process. By converting fossil fuels into a mixture of hydrogen (H₂) and CO₂, the CO₂ is separated and can be stored, while H₂ is used as a fuel for the cement process. Pre-combustion capture is considered more energy-efficient than post-combustion, but it requires additional investment into equipment and processes.

Direct separation of CO₂

The direct separation of CO₂ from cement plant flue gases is using various techniques such as membranes or adsorbents. It has the advantage of potentially lower energy consumption and smaller infrastructure requirements, but it is still under development and faces technical challenges. 

The capture and recovery of CO₂ for reuse by converting it into valuable products with the aim of achieving carbon neutrality is an important topic in industrial research and the development of innovative technologies. Facilities for CO₂ capture and storage can be installed in the cement industry to remove the CO₂ from the flue gas and subsequently allow purification, liquefaction, and storage. 

Benefits of carbon capturing in the cement industry

Implementing carbon capturing technology in the cement industry offers several advantages, including: 

• Reduced greenhouse gas emissions and carbon footprint  
• A sustainable cement production by minimizing CO₂ emissions without compromising the quality or functionality of the cement 
• Ensuring compliance with emission regulations and avoiding potential penalties or restrictions 
• Carbon utilization, e.g., for producing building materials, or even creating valuable chemicals  

While carbon capturing technology holds great promise, several challenges need to be addressed. These include the high cost of implementation, the need for infrastructure development, and efficient process control. Also here, TIC monitoring can contribute significantly.  

As technology advances and awareness grows, the cement industry is increasingly investing in research and development to overcome these hurdles. There are the first countries e.g., Switzerland, rewarding utilization of carbonated recycling cements in the building industry by refunding carbon tax.  

Outlook

As global efforts to combat climate change intensify, carbon capturing in the cement industry emerges as a crucial solution, paving the way for a greener and more sustainable future. By implementing these various methods, cement manufacturers can significantly reduce greenhouse gas emissions while ensuring the production of sustainable cement. TIC measuring methods as shown above enable a reliable and efficient monitoring of carbon capture and utilization processes.  

Read our e-book on the analysis of cement and other building materials and learn about powerful methods that can be used to reliably implement the carbon storage approaches presented.

¹ cf. Germany 2022 754 Mio. metric tons – Umweltbundesamt