The Green Cement Plant Of The Near Future

Robert Shenk, FLSmidth, provides an overview of what ‘green’ cement plants could look like in the near future.

A decade from now, the cement industry will already look very different than it does today. As the realities of climate change continue to hit home, social pressure on heavy emitters will increase and financial pressure will follow, forcing cement producers to act. There will be no more time to hide behind targets or roadmaps; global tolerance will have been exhausted. The cement industry has a responsibility to follow through on all the things it has promised.

As a leading supplier to the industry, FLSmidth feels this responsibility keenly. The company has solutions available now, with more in development, but the priority is communicating these solutions to cement producers. Because if you cannot visualise what a cement plant will look like – if you do not believe in it – it is not going to happen. This article is an overview of the cement plant of the near future, from the quarry to dispatch. It may not look so different from a plant you would see today, but it is. The difference is in the way it is operated, what is being put into it, and some of the supporting technology.

While total transformation of the quarry is not foreseen in the near future, there will be some key differences. First, the electrification of material extraction and transport – switching from diesel to electric-powered vehicles in the quarry is a relatively simple way to reduce carbon emissions in this part of the cement process. In fact, a recent pilot project at a Swedish quarry realised a 98% reduction in carbon emissions through the use of electric machinery.

Furthermore, the quarry may become a lonely place because many of these electric vehicles will also be fully autonomous. This electrification will require additional power sources, but in the next decade, more cement plants are expected to take control of their energy supply by building wind and solar installations on site. This will ensure they have the clean energy they need to power not just their quarry operations but increase electrification throughout the plant.

Besides the quiet from electric engines, quarries may not appear as busy as in the ‘peak clinker’ years, thanks to the increased uptake of supplementary cementitious materials, including calcined clay, which is to be discussed in further detail later in the article.

Crushing operations will be smarter and more efficient, taking advantage of Industry 4.0 technology to conserve energy and maximise availability. Machine learning-driven vision systems will help prevent blockages, while an emphasis on hard-wearing parts and easy maintenance will ensure minimum downtime.

Stockpile management
More efficient blending will enable greater chemistry control and grinding efficiency – so the emphasis on this section of the plant will be on advanced stockpile visualisation technologies. The equipment might look the same, but quality control will be vastly refined thanks to the use of software programmes like QCX/BlendExpert™ Pile and Mill, which help cement plant operators gain greater control over their raw mill feed. 3D modelling and fast, precise analysis provides the greatest possible insight into stockpile composition, enabling the optimisation of blending with minimal effort. All of this means that the raw material will be prepared to maximise the utilisation of SCMs.

Raw grinding
Raw grinding operations will be focused on vertical roller mills, which are able to achieve greater energy efficiency, increased productivity and higher availability. Additionally, the control potential for VRMs (when the main drive is equipped with a VFD) is far superior than for ball mills or even hydraulic roller presses. This enables a greater degree of optimisation, which in turn improves kiln stability and facilitates increased use of alternative fuels and the use of more diverse raw materials.

The biggest changes to the plant will be seen in the kiln. First, less clinker will be produced in proportion to cement production, replaced in increasing quantities by SCMs. Secondly, the fuel make-up will continue to evolve, taking advantage of advanced burners and other combustion technologies to co-fire a mix of alternative fuels including waste products, biomass, newly engineered fuels from waste streams, oxygen enrichment (so-called oxyfuel injection) and even hydrogen. Precision dosing will enable careful kiln control to maximise clinker quality, while solutions like the HOTDISC® Combustion Device will enable a wide range of fuels to be used. It is worth noting that 100% fossil fuel replacement is possible with existing technologies, but it may take another decade or more for the waste streams to catch up with demand. In addition, the green cement plant of the future will have to consider how green these alternative fuels actually are.

Waste heat will also be utilised, not just in the pyroprocess but also in other areas of the plant, for example to replace hot gas generators. Waste heat from the clinker production process will be captured and used to offset the remaining energy demands of the plant.

Source:World Cement, Published by David Bizley, Editor

Post time: Apr-22-2022