Global Cement EnviroCem Conference on Environmental Technology for Cement & Lime
A review of the 1st Global Cement EnviroCem Conference on Environmental Technology for Cement & Lime - Düsseldorf, April 2008
By Robert McCaffrey, conference convenor
The Global Cement Environmental Conference and Exhibition 2008 took place at the Radisson SAS Scandinavia Hotel in Dusseldorf 14-15 April 2008, with over 100 attendees from 22 countries, including representatives from most of the major cement and lime producing companies. The event featured reusable low-impact cotton delegate bags, recycling of conference materials and an organic gala dinner. Delegates also visited Dyckerhof's Geseke cement plant to view the latest environmental innovations in action.
The Global Cement Environmental Conference and Exhibition was organised to bring environmental impact abatement to the forefront of the agenda for the cement industry, and it included sessions on best available environmental impact abatement technology, alternative fuels, filtration advances, emissions measurement and control and alternatives to OPC. Environmental managers, filter technicians, fuel economists, lobbyists, equipment providers, additive companies and many other interested parties were in attendance. Greenpeace – although invited – did not attend, saying that "the cement industry is under our radar."
In a fascinating straw poll, a show of hands at the start of the conference suggested that 80% of those in the conference room believed that we are in a period of global warming (whereas 20% did not). Of the 80% that did believe that we were in a period of global warming, 80% believed that it was man-made (and 20% did not). This result does not quite tally with the IPCC's suggestion that it is 90% confident that most of the (measurable and irrefutable) warming in the past 50 years is due to humans. Only time will tell who is right on this question.
The first presentation at the conference was by David Pocklington of the British Cement Association, who spoke not only about safety, but also about Phase III of the EU ETS. It now appears that there will be a single EU-wide cap on CO2 emissions, rather than the current system of National Allocation Plans (NAPs). There will be an annual reduction of 1.74% in the cap between 2013 and 2020, leading to a 21% reduction compared to a 2005 baseline. There will be auctioning of allowances (with governments compelled to undertake the auctions but allowed to keep the revenues), although there will be free allocations to 'competitively impacted industries.' It is not yet clear whether cement and lime would be included in the latter category. There are no current plans to address 'carbon leakage' – imports from non-carbon-constrained foreign countries.
Dirk Lechtenberg of MVW then went on to speak about the use of alternative fuels in the German cement industry, compared to use in other EU countries. Dirk stated that 55% of the heating demand of the German cement industry was supplied by refuse-derived fuels (RDF), and that the gate fee levied by the industry was typically Euro15-45/t, depending on the material characteristics. Although the use of RDF can lead to a 15% efficiency loss and reduction in clinker production, this is made up for by the Euro33m in gate fee earnings, and Euro177m saved on fuel each year by the industry in Germany. Dirk pointed out that RDF use varies around Europe, depending on local laws and individual market situations, ranging from countries where production is important (for example in sold-out Spain, where RDF makes up just 5% substitution) to countries where efficiency is more important (such as the Netherlands, with 90% substitution. He concluded by saying that the German cement industry is now having to fight for waste. This was a theme that came out strongly in discussions throughout the rest of the conference – that the cement industry is being out-bid by the chemicals, power, paper, ceramics and glass industries for higher-specification wastes, and that we are being left with lower and lower quality materials.
Alexander Hanf of Powitec then described his company's technology for burner control. Through flame shape and emission characteristics, and using non-linear model predictive control to correlate flame shape with NOx, CO and O2, the software system optimises the burner for fuel efficiency.
Werner Rungger of Petro Miljo AB of Sweden detailed a study using different NOx-reduction reagents in seven different cement plants. He concluded that Petro's ammonium hydroxide selective non-catalytic reduction (SNCR) system was superior to the use of urea, both in terms of reaction efficiency, and cost-effectiveness.
Giovanni Quazzo of Gruppo Chimico Dalton gave an impassioned presentation on the use of an aqueous solution of sodium polysulphide – Decrom - for the reduction of chromium VI in cement. Giovanni stated that his company's patented solution was as effective as stannous sulphate for chromium reduction, but at nearly the cost of the much cheaper iron sulphate.
The conference then progressed into its third session, on alternative fuels and the environment. Dieter Jerschl of Vecoplan, started by explaining that his company had its roots in the wood processing industry, and who also proudly stated that of the 300 employees at the company, a laudable 26 of them are apprentices. He detailed some of the steps required for processing of municipal waste into RDF, from a pre-shredder with air-knife, through to screening, separation and storage prior to use. Interestingly, these are all steps that will be required for processing of previously landfilled waste. The use of RDF appears to be a 'no-brainer' for the cement industry in most areas of the world. For example, Siam Cement Co saved itself US$105m in coal costs, after increasing its substitution rates using some of the 10,000t/day of waste generated by Bangkok, only 100km from its main cement plants at Saraburi.
Adolf Wong of Satarem China – representing half, he said, of the world's cement production – presented a co-authored paper on an integrated cement waste management system. The heart of the process is a resource reuse incineration process (RRIP), which is integrated into the cement plant. This allows the use of calcined ash as an alternative raw material, the production of pre-heated air for precalcination, and the generation of power using a high-temperature steam boiler. Adolf suggested that the main benefits of the system are production increases due to increased air flow, electrical generation, the generation of lucrative renewable energy certificates and the receipt of waste treatment fees. Following the presentation there was intense questioning of Mr Wong – an indication of the interest of the cement industry in his company's concept.
Thomas Marx of ABB finished the day off with an explanation of his company's model predictive control system, which can be summarised 'measure, predict, act, repeat.' The smart thing about ABB's system is that it can take into account both technological and economic constraints when optimising a cement production line.
The evening's environment-themed gala dinner took place in the unusual setting of the Hombroich nature garden park and outdoor art museum area, and featured delicious local organic food.
Second day
The second day of the conference kicked off with a session on filtration advances. Ralf Esser of Intensiv-Filter began by describing the kiln bag filter conversion at Dyckerhoff Zement's Geseke plant, the hosts of the conference-organised plant tour. The paper discussed the benefits of ESP conversions and retrofits (a low-cost means of improving emissions) and went on to introduce the Geseke conversion as an example. In this case a new housing was positioned on the dust hopper, with all existing dust transport systems remaining as before. In response to a question from the floor, Mr Esser said that, with the exception of high-temperature applications, "the ESP is dead."
Christian Straif followed with a paper on Scheuch's filter technologies. The Scheuch EMC ('energy minimising concept') filter, Mr Straif said, has been around for seven years and combines the advantages of ESPs and pulse-jet filters. Video footage showed the audience how the EMC low-pressure cleaning breaks filter cake which remains agglomerated as it falls—requiring 60-80% less compressed air consumption, 10-30% less fan energy and resulting in 80% longer bag life and lower dust emissions.
Georg Rathwallner of Evonik Fibres presented a paper on bag filter materials, providing an overview of different fibres' performance in different applications. Mr Rathwallner proposed various fibre materials and blends for each application within the cement plant and compared performance data for polyester fine fibre with a P84/polyester blend in the clinker mill—the P84/polyester blend was said to be stable for 60 months whereas the polyester fine fibre bags required changing after 7 months.
FLSmidth Airtech contributed a paper presented by Carl Vilhelm Rasmussen, detailing the reduction of cement kiln dust emissions by combining ESP and fabric filters in a common casing at Titan's Kamari plant in Greece. The economic advantages of a conversion compared to the installation of a new filter were explained (reuse of structure, dust handling, etc.) and the disadvantages were also noted (the ~1% of dust that escapes the ESP is usually very fine and forms a dense cake on the fabric filter). In conclusion, however, a 40% power saving when the hybrid filter was selected over a new bag filter suggested that Titan Kamari may have made the right choice.
The first paper in session five ('What is not measured cannot be controlled') examined the impact of climate change compliance on cement companies. Raine Isaksson of Intec Services presented the paper, suggesting new benchmarks with which economic, environmental and ethical performance of a business can be measured, as a means of detecting improvement potential and guiding decisions for sustainable operation. Mr Isaksson stressed the importance of understanding the whole system before trying to solve a problem, and used the 'failure' of biofuels as an illustration to this issue. "Things can change very quickly if you don't understand the full system—you could be doing the wrong thing," he said. Healso suggested that though controls such as APC are beneficial, variability should be controlled further upstream and 'alternative' fuels should be subject to the same requirements as 'ordinary' fuels for this reason.
Volker Schmitz of PCME then presented on the subject of dust monitoring, asking whether it is a regulatory must or a cost-saver in itself. Mr Schmitz gave an overview of emissions standards before going through the various methods of making the measurements: gravimetric, optical and electrodynamic. The advantages of the latter, Mr Schmitz said, are its measurements' independence of particle velocity, and that contamination of the sensor (when it gets dusty) does not affect the reading (unlike the gravimetric and optical solutions).
Session six then got underway, focusing on the topic 'Alternatives to OPC.' Christophe Paulo of Imerys explained how functional minerals and materials can be used to improve the in-application and environmental performance of cements and concretes. Mr Paulo said that recent advances in mineral processing technologies have led to the availability of a range of minerals, including metakaolins with virtually zero CO2 contribution. Results of performance tests on metakaolin, perlite and diatomite were presented. Compressive strength benefits were greatest in the substitution ranges of 0-20% for metakaolin, 0-10% for perlite and 0-20% for diatomite.
The final paper was delivered by the double act of Bill Flederbach of TurboGreen and Mike Sumner of Grace Construction Products. This informative paper, entitled 'Maximising CO2 reductions while increasing production and improving cement quality,' held the crowd right to the end of the conference. Mr Flederbach began by describing the various carbon cap and trade mechanisms. The Voluntary Emission Reduction mechanism (VER) in the US "is becoming very robust, very quickly," he noted. Approved emission reduction methodologies were summarised and, using the example of ACM0005 – Cement blending methodology – the trading mechanism registration steps were explained. Mr Sumner took over to describe the role of Grace's quality improvers in clinker substitution. A third section of the presentation looked at the global carbon market: there are 114 Joint Implementation projects in the pipeline (including two cement projects) and over 3000 Clean Development Mechanism projects (including 100 cement projects). With Kyoto Phase II ending in 2012, Mr Flederbach ended the presentation by urging cement producers to act now. His other final nuggets of advice included to de-bottleneck operations through cement blending and to evaluate all methodologies and all options before the project starts.
Awards and conclusions
At the well-attended farewell party, Adolf Wong from Satarem China was awarded third place for his paper on the resource reuse incinerator process. In second place was Intensiv Filter's paper on the kiln bag filter conversion at Geseke (a plant that was to be visited the next day on the conference field trip). In first place was the conference's final paper, co-authored by TurboGreen and Grace, on maximising CO2 reduction, production and quality. Cemag was awarded the best exhibition stand prize.