Process engineering: a forgotten hero?

Decarbonisation is the most important megatrend facing all industries and it will continue to be so over the years to 2050. This is as true for the cement industry as any other sector – perhaps even more so. The cement industry is responsible both for a significantly larger proportion of global carbon emissions than most other industries and, thanks to the large quantity of carbon emissions inherent to its process chemistry, it is particularly challenging to abate.

The general approach to delivering a decarbonised cement industry should however be familiar to most in the industry. It comprises four key technological pathways:

• Improvements in energy and process efficiency.
• Substitution of fossil fuels with lower-carbon alternative (waste-derived) fuels.
• Reducing the clinker factor in cement via high-quality supplementary cementitious materials (SCMs).
• Carbon capture, utilisation, and storage (CCUS).

These strategies were laid out by the International Energy Agency (IEA) as far back as 2009 in its Cement Technology Roadmap of that year. They have now been broadly adopted by many industry roadmaps to net zero, including the Global Cement and Concrete Association, which represents many of the world’s leading cement producers.

Decarbonisation and digitalisation

Successful implementation of these four pathways brings us to a second megatrend that is currently reshaping the way industries work: digitalisation. Simply put, the process changes needed to deliver decarbonised cement production are likely to require advanced automation and process control systems to implement effectively.

The approach taken by KHD to these overlapping trends is summarised in its recently launched ‘Cement beyond Carbon’ campaign. This integrates the company’s vision for a decarbonised cement industry with twin missions to offer the most efficient solutions for a sustainable cement industry and to provide the most environmentally friendly technologies for the manufacture of the world’s most-used product.

The choice of ‘Cement beyond Carbon’ as its tag line also makes a much more basic – but critical – point, as company CTO Matthias Mersmann pointed out. “Even when thinking ‘beyond carbon’, there is still cement. Cement is one of the world’s most important products and we do not see a future where that is not the case. Cement is literally one of the foundations of modern life and will play an essential role in meeting many of the UN Sustainable Development Goals. There is no future without cement – but cement needs to be decarbonised.”

Process, process, process

There is another basic idea that must also be mentioned when discussing cement decarbonisation, although it is much less discussed than digitalisation. And that is process engineering. A deep understanding of process engineering will be an essential prerequisite for effective implementation of any of the four technology pathways. Whether looking for ways to enhance plant efficiency, switching to higher rates of alternative fuels or SCMs, or integrating CCU technology into a plant, it always comes down to process competencies.

“KHD has long been known for its strong process engineering skills”, says André Sybon, General Manager at KHD, who leads the company’s Centre of Excellence in Cologne. “It is in our DNA and is the reason so many of our innovations have become the standard at cement plants today.” A quick look through the company’s history proves the point. KHD was the first to install a cyclone preheater tower back in 1952; this was followed by the industry’s first flash tube calciner – the PYROCLON^® – a decade or so later in the mid-1960s and by the short kilns that reduced heat consumption for the cement production. The world’s first low-NOx calciner was also introduced by KHD in 1985.

In recent years, the company has been at the cutting edge of technologies that lower emissions, reduce energy consumption, and support high alternative fuel substitution rates. “For more than seven decades, we have aspired to take leadership and drive technological change in the cement industry”, says Alexander Knoch, KHD’s Innovation Management Officer. “This would not have been possible without our deep understanding of process engineering: you simply cannot do what we have done without it. And it lies at the heart of our vision for the future.”

“We expect cement plants to be much more diverse than we have seen in the past”, explains Mersmann. “This means there will not be a single pathway into the future, but many, all of which will be tailored to the needs of the individual plant. Implementation of these solutions will depend on a range of factors, including: plant location, size, and layout; the availability and types of raw materials, alternative fuels, and SCMs; and some individual commercial realities. The future is thus one of adaptable solutions, designed by experienced process engineers, who are able to successfully customise technologies and processes to specific needs and conditions.”

The next step

Defining KHD’s overarching approach to this future is its ‘Cement beyond Carbon’ vision, which is split into two timeframes: the period to 2030 and then 2030 and beyond.

• The road to 2030 encompasses existing and soon-to-be-commercialised technologies to reduce CO₂ emissions.
• The next chapter is yet to be fully written but will take the cement industry to complete decarbonisation.

“We already have a number of solutions either already in commercial operation or ready to be deployed that will support the cement industry in its ambitions to reduce carbon emissions to 2030”, notes Rainer Krüper, General Manager responsible for sales and project execution at KHD. “These include our Pyrorotor^® rotary combustion chamber for alternative fuels, clay calcination systems that produce a high-quality SCM at lower carbon cost than clinker, and oxyfuel combustion as a key enabler of CCUS, as well as our KHD ProMax^® digital suite.”

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