In Practice: can cement be sustainable?

Dr. Geoff J. Nesbitt, CEO of Verditek, looks at how technology can reduce emissions for contractors.

Usually, associating the words ‘concrete’ and ‘footprint’ will conjure up images of perfectly preserved footprints pressed into setting concrete by small children or animals – a common fixture in many municipalities.

However, as the most abundant man-made material on earth, conventional concrete comes with a significant emissions problem. As concrete’s main by-product, CO2 emission from cement production has a huge carbon footprint.

7% of global man-made greenhouse emissions come from cement and in 2017 alone global cement production was responsible for around 4 billion pounds of CO2 emissions. Dwindling CO2 supplies recently impacted various industries in the UK, sparking conversations around the potential re-use of CO2 captured in other industries.

While this could become a longer-term goal, cement producers should have already begun to explore carbon capture solutions in reaction to intensifying pressure to reduce greenhouse gas emissions on a global scale.

Pressure Rising

Carbon capture technology will essentially provide cement producers in any country that is applying the COP21-Paris accord rules with a renewed license to operate.

The 195 governments that signed the Paris Agreement in 2016 (possibly excluding America) will be implementing COP21 as a regulation that forces their industries to take action.

From the cement industry to oil, gas, manufacturing and beyond, industries must recognise COP21 as the official prompt to start budgeting for adjustments they must make to meet the moving climate change targets and to explore solutions that will realistically aid them in meeting those targets.

It’s not just governments that are demanding change. There is mounting demand for sustainability from the general public too.

One survey conducted by YouGov on behalf of the Carbon Trust found that 55% of UK consumers would feel “much more than positive” about a company that has reduced the carbon footprint of its products.

Moreover, two-thirds of consumers across the UK, France and Germany would now like to see a recognisable carbon footprint label on goods. But it’s not all about everyday products.

This growing demand for sustainability is likely to extend to every aspect of the world that surrounds us, from eco-friendly materials to greener energy generation in housing, commercial buildings, infrastructure and public spaces.

National Geographic reports that nearly 70% of the world’s population will live in cities by 2050. That’s a 55% increase on today’s figure. While cities cover just 2% of the world’s land surface, they account for 70% of greenhouse-gas emissions.

30% of those emissions are generated by buildings alone. While there are viable alternatives to cement in residential construction with sections such as roofs, walls and floors prefabricated from either wood or MgO materials, commercial and industrial structures which are subject to higher stresses and loads will continue to rely on cement.

Some producers have successfully introduced recycled aggregates into the cement mix, yet only up to 10% can realistically be used in a mix before the strength of the cement is compromised.

As the sustainability movement continues to develop, the pressure to reduce carbon emissions will continue to rise for cement producers.

A Matter of Cost

Given the costs associated with implementing carbon capture technology, it’s hardly surprising that the global cement industry has been seeking subsidisation or some form of financial relief from governments pressuring them to take on the burden of reducing the carbon output.

While there is currently no offer of subsidies, some governments have introduced carbon credit schemes. These, however, have been criticized for falling short of making a significant impact, and in some quarters are seen as a means for governments to capitalise on carbon production.

The cement industry would prefer not to be confronted with the expense of implementing any solution, but it cannot continue to vent CO2 into the atmosphere without consequence.

The only viable option for cement producers is to seek out emerging solutions that can achieve the same results as conventional contractors in a more affordable way.

RFC technology is a relatively compact cost-effective technology for mixing gas with solvents, which is the primary method for washing CO2 from flue gas.

RFC technology has the potential to offer a more affordable method to strip the CO2 from the kiln exhaust thanks to the equipment’s lower cost per tonnage. An RFC unit can be placed next to the exhaust chimney with the exhaust routed to the contactor where the amine solvent will react with the CO2.

The use of these solvents is established and well known to cement producers, however, the latest innovations in RFC technology is less known and the advantages it can offer in a smaller operating burden.

A Step in the Right Direction

Compared to conventional contractors, RFC is more robust and has the advantage of working with precipitating solvents. It could even be possible for producers to lease the technology instead of buying it outright, shifting the proposition to an operating budget instead of a major capital purchase.

While the captured CO2 will still need to be sequestrated or put to use elsewhere – perhaps in some of those industries experiencing a CO2 shortage – RFC provides the first step towards this by enabling the cement producer to reduce the cost of meeting stringent regulations and intensifying demand for carbon footprint reduction from all directions.