As Germany’s chancellor Angela Merkel prepares for a third term in office, the country’s cement association VDZ gathered in Düsseldorf for its four-yearly congress. Held in the Maritim Hotel between 25-27 September, the event brought together the might of the German cement industry as well as speakers and guests from as far as China for an update on the latest cement technology advances and the sector’s drive for sustainable development.
After Gerhard Hirth, VDZ president, opened the 2013 VDZ Congress in the presence of over 600 delegates, Howard Klee, former director of the WBCSD’s Cement Sustainability Initiative, detailed the latest developments in terms of sustainability in the cement industry and thus provided a suitable introduction to the key themes of the congress.
VDZ’s Martin Schneider outlined the main topics of the conference and set the stage for the following two days of presentations. These underlined the importance of the industry’s efforts towards sustainable development: energy efficiency and waste heat recovery, grinding optimisation, emissions control and new, lower-carbon cement types. However, the overarching theme of sustainable development was also supported by further relevant presentations dealing with issues such as biodiversity and the contribution the cement industry can make in this field.
Sustainable energy use
Cecilia Tam of the International Energy Agency tracked the current development and outlook of the energy markets. The resurgence of oil and gas production in some countries and the retreat from nuclear in others, as well as signs of an increasing policy focus on energy efficiency, show a shift in global energy systems. However, high oil and energy prices have provided a brake on economic recovery while unsustainable energy systems appear to persist. Energy demand is expected to increase by over a third by 2035 as China, India and the Middle East lift their living standards while in terms of power demand, the emerging markets are expected to drive a 70 per cent rise in global demand. “In the period to 2035, two thirds of the economic potential to improve energy efficiency remains untapped,” said Ms Tam. “If the corresponding energy efficiency measures are implemented, it is expected that energy demand growth to 2035 can be halved – oil demand savings equal to the oil production in Norway and Russia.” For the cement industry, she quoted a best-available technology energy savings potential of around 19 per cent. Ms Tam offered carbon capture and storage (CCS) as a part-solution although she warned on the lack of projects and the high costs associated with the development of the technology.
The IEA Cement Roadmap Timeline sets out a course to lower the cement sector’s energy demand by means of four levers. The majority of demand reduction is expected to come from CCS (56 per cent) with a smaller but significant share obtained through the use of alternative fuels (24 per cent). The raising of energy efficiency and clinker substitution each represent an additional 10 per cent. However, given the developmental stage of CCS technology and its current high cost, its large share in potential energy reduction could be viewed as a particularly ambitious target for the cement industry.
Waste heat recovery
Meanwhile, the industry’s efforts to reduce its energy use and costs were evidenced by a series of presentations that highlighted the importance of waste heat recovery (WHR). Fabio Wider of Holcim (Switzerland) shared his company’s experiences with waste heat recovery at the Untervaz cement plant. At this 1900tpd five-stage suspension preheater kiln, the company captures 360°C kiln flue gas at the preheater and 300°C cooler exhaust gases and feeds them back into the process. After an initial underperformance of the flue heat exchanger, design modifications – installing partition plates in the dust bins similar to the structures in ESPs – were carried out. He stresses that often knowledge to solve WHR integration issues was already in the domain of cement technology.
Andreas Werner of TU Vienna delved further into WHR and power generation at cement clinker production, offering an energetic comparison of different WHR techniques. He also presented the latest developments in terms of the supercritical CO2 cycle, which can be considered the state-of-the-art WHR system which offers potential for use in the cement industry.
Gernot Kirchner, Lafarge Zement GmbH reported on levers, potential and limitations of pursuing energy efficiency in cement production.
Alternative fuels
The adaptations required to fire kilns with alternative fuels came to the fore as three cement producers shared their experiences. Sandro Buzzi of Buzzi Unicem, Italy, explained this company’s path from municipal solid waste to energy. Jaroslaw Sawecki, Cemex Poland, outlined the effect of a new drum drier to improve RDF quality and combustion at the Chelm cement plant. The new 3000tpd line at Italcementi’s works at Rezzato, Italy, was designed to enable the sustainable production of cement – highlighted by Giovanni Cinti, Italcementi.
Emissions control
One of the key topics under discussion at the conference was the reduction of NOx. Ruediger Matheis, Dyckerhoff AG, offered the latest experiences on the potential and limits of high-efficiency SNCR for non-calciner kilns. The development of highly-efficient NOx technology holds a double challenge: to reach a high as possible NOx reduction (given that 100 per cent reduction is not possible) and the avoidance of ammonia slip. To test the limits and potential, Dyckerhoff put its Göllheim works, Germany, through its pace in terms of NOx reduction and Mr Matheis explained the various actions taken by the company.
Detlef Edelkott of Schwenk Zement added to the audience’s knowledge by explaining the operational experience with catalytic NOx abatement using high-dust SCR technology, while the semi-dust SCR technology used by Lafarge’s Austrian Mannersdorf plant was the subject of the talk given by Bernhard Koeck of Lafarge CTEC Vienna. Further perspectives to NOx reduction were offered by Helmut Leibinger of Rohrdorfer Gruppe, who highlighted the firm’s experience with tail-end (or low-dust) SCR Technology for NOx and NH3 mitigation and Gerhard Philipp, Wopfinger Baustoffindustrie, who presented the new regenerative thermal oxidation (RTO) with integrated NOx reduction.
Daniel Crowley of Titan America touched upon a key environmental issue for cement producers, particularly in the USA: mercury emissions and their abatement. He pointed delegates to the fact that the solution to mercury issues is highly plant specific and offered several pieces to help solve this puzzle.
Grinding optimisation
The congress also offered a platform to discuss grinding optimisation and the advances made by several grinding specialists were presented. FLSmidth’s Jesper Havn Eriksen introduced the OK mill as an optimised and versatile grinder while Daniel Strohmeyer of Loesche outlined the comprehensive approach of vertical roller mill (VRM) technology. VRMs were also the subject of the presentations by Thomas Schmitz (ThyssenKrupp Resource Technology) and Robert Schnatz’s (Gebr Pfeiffer SE) as they explained the Quadropol RD and the operational experience from India’s first MVR VRM for cement grinding, respectively. From China’s Hefei Cement Research Institute¸ Bao Wei expanded on the applications of HFCG roller press grinding systems. The production of slag-containing cements by the separate grinding of Portland cement and GGBS slag components and subsequent mixing was the focus of HeidelbergCement’s Anton Kollman contribution.
Lower-carbon cements and concrete
The congress also offered an insight into the development of lower-carbon cements. The performance and standardisation of low-clinker ternary cements was the focus of the presentation by Michel Delort of the Associations Technique de l’Industrie des Liants Hidrauliques (ATILH). He tracked the development of the standardisation of such cements.
Karen Scrivener of the École Polytechnique Federale de Lausanne, Switzerland, offered the research highlights of a decade of Nanocem since its inception in May 2002. She expressed concern about the levelling out of clinker factor reductions and advocated new solutions to be found. However, she pointed out that successful development of such solutions depends on a number of prerequisites. She stressed the importance of science in understanding how microstructure is formed and reacts in the general acceptance by cement users. Consequently, Dr Scrivener sketched the developments in research, the methods used and results obtained.
After a further three presentations around lower-carbon cements, the VDZ’s own Christoph Mueller rounded off the subject by reviewing the durability requirements for concrete today and in the future, offering a benchmark for cement development.
Conclusion
The congress also offered a stage to other important topics that enable cement producers to develop and run their operations in a sustainable way.
The protection of biodiversity in quarries was key to the presentation of Michael Rademacher of HeidelbergCement Group Brussels. “Nature conservation management and public relations are essential for a sustainable raw materials extraction,” he said. The importance of biodiversity management has been increasing in recent years and biodiversity is now part of the legal liability system in Europe. Quarries show a high level of biodiversity and in many cases, species occurrence is higher in the mining area than in the surrounding area. Therefore, quarries can be viewed as offering an “ark of Noah” function, stated Dr Rademacher. Moreover, active habitat management can increase of biodiversity. He concluded his talk with a fitting request “To give back to nature more than we have taken.”
Article first published in International Cement Review, November 2013.
