March 4. 2024. 6:02

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How carbon capture is helping clean up the cement industry


“Electrifying everything” has become a key solution to tackling climate change, but for the cement industry — which relies heavily on fossil-fuel-generated industrial heat — the challenge is more complicated.

Compounding the problem, there are few — if any — alternatives to the limestone that cement producers use as a raw material, which also produces CO2 emissions.

Cement production accounts for 8% of global CO2 emissions. While the IEA’s Net Zero by 2050 Scenario calls for 3% annual declines in the direct CO2 intensity of cement production to 2030, this increased by 1.8% per year between 2015 and 2020.

Curbing industry emissions while producing enough cement to meet growing global demand is therefore likely to rest on the use of low-carbon technologies like carbon dioxide capture, utilisation and storage (CCUS).

Cement production accounts for 8% of global CO2 emissions. Carbon capture, storage and ultilisation (CCUS) will be key to curb emissions. [Shutterstock/Bilanol]

Testing times

CCUS can harness the emissions from cement manufacturing to help the industry realise its decarbonisation ambitions. While the technology is in its infancy, efforts are underway to scale up CCUS system deployment for cement manufacturing.

Mitsubishi Heavy Industries Engineering, a Mitsubishi Heavy Industries (MHI) Group company, has agreed to conduct a demonstration testing programme at an existing cement plant with the Tokuyama Corporation, one of Japan’s leading chemicals and cement manufacturers. A compact CO2 capture test unit will be installed at Tokuyama’s plant in Shunan, Yamaguchi prefecture, and the testing is due to run for nine months from July 2022.

The CO2 capture test unit — roughly equivalent in size to two 20-foot shipping containers stacked on top of one another — will harness CO2 emissions from the plant’s flue gases, allowing the impurities in the gas to be analysed.

Although not part of this demonstration program, at this point, CCUS systems compress captured CO2, which is then either stored or used in a range of industrial applications. For test purposes, the captured CO2 will be returned to the stack once it has been analysed.

A compact CO2 capture test unit will be installed at Tokuyama’s plant in Japan. [MHI]

What happens next?

Nine months of accumulated know-how and experience from real-world operations will help inform plans to scale up this technology and deploy CCUS systems throughout the global cement industry.

As the IEA states, CCUS has a key role to play in helping the world reach net zero by 2050. And nowhere is this technology more important than in the cement industry.

While some hard-to-abate heavy industries can switch to cleaner fuel sources, like hydrogen, the cement industry’s reliance on CO2-emitting limestone as a raw material leaves it set in stone, so to speak, making CCUS an essential tool.

Once CCUS systems are operating at scale, the bulk of captured CO2 from cement and other industries will be stored securely, deep below ground. But a growing CO2 value chain is developing that is turning this waste product from a liability into an asset.

Captured CO2 from cement industry flue gases can be injected into concrete as a raw material. It is encouraging to see these examples of the circular economy in action.

What is claimed to be the world’s first carbon-negative concrete has been produced in Japan. Called CO2-SUICOM, it is capable of absorbing CO2 in the curing process. Liquefied CO2 is mixed with concrete while it is hardening, producing a strong product that stores a large amount of carbon dioxide. We could see a future where our walls and building blocks are also CO₂ stores.

Captured CO2 can also be used in a growing number of other industrial applications, from chemical manufacturing to putting the fizz in carbonated drinks.

Solutions such as CO2NNEX digital platform — a joint venture between MHI and IBM — are being developed to analyse, record and verify volumes of captured, stored, transported, utilised and traded CO2, connecting carbon emitters with offtakers in various industries.

Forward-thinking

Making captured CO₂ a tradable commodity could go some way to overcome the main barrier associated with applying CCUS systems to the cement — or any other — industry, which is cost. While the global market for sustainably made concrete will certainly grow, many consumers may be reluctant to pay a “green premium” for concrete manufactured using CCUS.

But attitudes are changing as awareness of climate change increases. This can be seen in industry efforts to curb emissions: such as increasing the efficiency of kilns, switching from heavy-emitting fuels like coal to natural gas or biomass, and reducing the clinker-to-cement ratio (including a greater focus on blended cements).

Working in parallel with low-carbon technologies like CCUS, these efforts can help the cement industry decarbonise operations and realise a carbon-neutral world. But the question remains, is it happening fast enough?