8th Global CemFuels Conference 2014
25 - 26 February 2014

The 8th Global CemFuels Conference and Exhibition has successfully taken place in Vienna, Austria, with around 190 delegates from more than 30 countries and a large and bustling exhibition area. The 9th Global CemFuels conference on alternative fuels for the cement and lime industries will take place in 2015 in Dubai.

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The Global CemFuels Conference has established itself as the foremost gathering for cement industry professionals in the field of alternative fuels. On the evening prior to the start of this year's conference in Vienna, delegates gathered in the Global CemFuels exhibition area, where 32 exhibitors of equipment and services for alternative fuels (AF) promoted their wares.

The next day, Dirk Lechtenberg gave the first keynote presentation at the conference. Dirk pointed out that Cemex is the cement company with the highest current AF use, at around 27%, but with other multinationals including HeidelbergCement, Buzzi, Lafarge and Votorantim catching up fast. More stringent emission limits are being brought in around the world, but TOC (total organic carbon) emission limits are difficult to reach for plants with a high TOC content in the raw materials. At the same time, mercury levels from energy-saving light bulbs that can contaminate some AF is potentially also a limiting factor in AF use. Dirk stated that AF use is increasing rapidly throughout the MENA states, as fossil fuel subsidies are being reduced and as states increase both environmental awareness and resource efficiency. He pointed out that more than enough municipal waste is available to supply the entire cement industry in the Middle East and North Africa. Dirk Lechtenberg suggested that cement companies are increasingly outsourcing AF projects to third-party companies, since "AF is not the core business of a cement producer."

David Hooper of Entsorga Italia next spoke on future trends in AF use in the cement industry. He pointed out that coal is a commodity that is open to speculation, with futures contracts worth approximately 15 times the value of real material currently available. David suggested that developed countries spend currently around Euro1/day/person on waste management, with landfilling now largely banned: the waste must somehow be used economically, with processing in a cement plant an obvious solution. David suggested that smaller mechanical-biological-treatment plants are becoming popular, to process more local waste while at the same time trying to gain some economies of scale. David concluded that the value of solid recovered fuel (SRF) is increasing worldwide, partly because the cost of alternative disposal is increasing. The finance director will always have the final say on the viability of any AF project. "SRF is becoming a commodity and is being marketed as such. In 20 years time, coal will be the alternative fuel."

Jan Theulen of HeidelbergCement next gave a cement producer's view of the use of AF around the world. Jan pointed out that the company has a turnover of around 14bn euros, and over 50,000 employees in more than 40 countries around the world. The company has achieved an overall substitution rate of 22% and is aiming for 30% by 2020. Two of the company's kilns in Europe have substitution rates of above 85%. Jan pointed out that the company is heavily investing in SCR NOx reduction technology for European kilns, as well as in optimising burners, O2 injection and CFD simulation, all of which can aid in AF use. Jan pointed out that finance directors prefer 'improvement without investment,' but that at some point, investment is required. He suggested that alongside logistical challenges which must be overcome, the optimised use of AF requires a multi-disciplinary team involved in de-bottlenecking, process optimisation and mechanical issues. China and Indonesia are moving ahead with AF use (sewage sludge seems to have strong potential in China), while Russia, Kazakhstan, Ukraine, Georgia and India are willing, but are starting from a low base. Jan suggested that biomass has good potential in central and west Africa, but stated that the cement industry must not compete with the food chain, or take materials from local villages and small enterprises. Several projects are ongoing in Tanzania, Togo and Congo. In the US, there are increasing opportunities for AF use, due to the increase in cost of landfilling (increasing at around 5% per year), although this varies from state to state. At the same time, the US EPA has stated that it is possible to use 30% SRF, classified as a non-hazardous secondary material, without reclassification of the kiln.

Ed Verhamme of Alternate Resource Partners next spoke on pricing factors for AF. The enforcement or lack of enforcement of environmental regulations in a particular jurisdiction may be one of the most important pricing factors for AF. Ed pointed out that former incinerators have reclassified themselves as waste-to-energy plants, thereby becoming 'recycling' plants and being subject to much lower permitting standards. Ed suggested that "once cost savings from AF become part of the budget for a cement plant, it becomes 'addicted' to the savings," which can be a problem if the waste stream changes. Cost factors include supply chain costs, collection, transportation, preprocessing, documentation, receiving, handling, treatment, co-processing, monitoring and reporting, with the hazard level also playing a role in determining costs. In developed markets, waste has become more valuable. Ed pointed out that many other players in the AF supply chain capture value, well before it arrives at the cement plant gate and he suggested that cement producers can reach beyond the gate to capture some of this value/profit for themselves. He asked 'Who owns the MSW waste market - the person who owns the waste, or the person who owns the solution?'

Session 2 at the conference, on the handling and processing of AF, was started by Rob Leighton of Saxlund, who spoke on AF handling systems 'from truck to calciner.' Rob suggested that pneumatic conveying lines should minimise bends and otherwise to reinforce bends with wear-resistant materials. He concluded that equipment needs to be robust, easy to maintain, have low power consumption and is easy to operate.

Adelbert Regeling of Keith Walking Floor Europe next spoke about the use of walking floors for receiving, conveying and metering of AF. He mentioned in detail the use of Keith Walking Floor's equipment at the Carmeuse plant in Ohio, capable of receiving up to 900t/hour of RDF.

Leos Volesky of Schenck Process started out by stating five golden rules of AF systems: use robust systems that are capable of coping with low density materials (without using 'monsters'); avoid bottlenecks since secondary fuels tend towards bridging; pay special attention to equipment positions and connections; allow for variability in density and flowability; and seek out expertise. Leos mentioned an important reference plant at HeidelbergCement Mokra plant.

Luigi Di Matteo of Di Matteo Forderanlagen carried on the theme of AF handling, and went on to speak about his company's solution for dosing of AF, the Di Matteo WeighTube, a continuous gravimetric weighfeeder. Luigi pointed out that gases have residence times in the process in the realm of one to 10 seconds, but materials have residence times measured in minutes to tens of minutes in different parts of the system, allowing the effective use of AF to neutralise fuel components (graph).

Johannes Scherleitner of Geroldinger GmbH spoke about storage and discharge systems for AF. One of the many different options that he mentioned was the Multigon octagonal modular AF storage silo concept and the Oszillomat rotating beam silo bottom for the promotion of mass flow.

Johannes Uttinger of A TEC mentioned his company's critical equipment for the use of AF, including modular fuel storage and dosing, the calciner fuel feed system, the combined feed chute and burner, and an AF-optimised combustion chamber. He briefly mentioned the A TEC Master system that allows the of use up to 100% AF.

Thomas Jennewein of FLSmidth Pfister spoke about the possibility of using coarse alternative fuels, using the well-known Pfister Rotor Weighfeeder for accurate dosage, pointing out that the ability to use coarse AF not only saves money on preparation, but also widens the variety of possible fuels that can be used.

Roman Eggert of Putzmeister then spoke on the handling of sludge-like AF, using piston pumps. Sludges include sewage sludge, animal carcass sludge, paint sludge and oil and hazardous waste sludge, drill cuttings sludge, contaminated soils and bio-wastes, ranging from low viscosity flowable materials to high viscosity materials like dewatered sewage sludge.

Luc Rieffel of Walter Materials Handling next spoke about his company's complete handing and storage systems for alternative fuels, based on the use of storage pits, a storage hall and an automated grab crane that manages dosing, mixing and storage hall capacity.

The final speaker on the first day of the conference was Christoph Winter of FLSmidth Wadgassen, a company composed of the former companies Koch Transporttechnik and of MVT Materials Handling and which is now the global technology centre for bulk materials handling of the FLSmidth Group. Christoph stated that typical systems always consist of a minimum of four steps: reception, transport, storage and dosing. FLS Wadgassen has created modular solutions for each stage which can be combined into a complete system.

Gala Dinner and Global CemFuels awards 2014

The Global CemFuels Awards Gala Dinner took place at the spectacular Palais Ferstel in the heart of 'Old Vienna.' A record-breaking nearly 1200 online votes were cast in the CemFuels Awards by AF experts in 42 countries. The 'outstanding AF project of the year' award went to Carmeuse Lime & Stone for its Grand River project, featuring suppliers Schenck Process, Keith Walking Floor, Process Plus, SMP welding, KFS and fuel supplier Vexor. Global AF-supplier of the year went to Brazilian company Eco-Processa, while the AF-user of the year award went to Cemex, for the third year in a row. Most innovative technology for AF use was the RDF Compact Plant, from Lindner. Industry stalwart and well-known consultant Ed Verhamme of Alternate Resource Partners was awarded the Global CemFuels 'personality of the year' award. Dr Joseph Kitzweger of Lafarge Mannersdorf cement plant was thanked, in advance, by delegates for hosting the Global CemFuels conference field trip.

After the gala dinner, delegates were invited to continue discussions at the Hilton Danube hotel bar, sponsored by Global CemFuels and Global Cement Magazine.

Soft factors/Pyroprocessing

On the second day of the conference, Ed Verhamme of Alternate Resource Partners started the programme with a paper on the 'soft' factors that contribute to a successful AF programme, including the style, staff, skills and shared values of the staff. Many projects concentrate on the 'hard' elements of AF, of strategy, structure and systems, but these projects may have difficulties without successfully incorporating the soft factors. Cultural factors may also be important; people generally want what is best and easiest for them, have a fear for their own safety and a fear of the unknown. Ed suggested that the person in charge of the AF programme in a cement plant or company should have a sufficiently high level of seniority to push through change, while the communications and public affairs department must be active and effective in persuading stakeholders that using AF is a positive move. He concluded that an alternative fuels company must work hard to provide service to its customers - the cement plant and the waste providers - in order to add value.

Egmont Ottermann of PPC Ltd, South Africa, next spoke about the use of social media to promote alternative fuels. He concentrated on the success of the 'AFR emissions and pyroprocessing in cement' LinkedIn group. This closed group has concentrated on a number of subjects including problems with AF, emissions, circulating elements, pyrolysis, gasification and regulatory tips and tricks. For example, Egmont suggested that rather than applying for a permit to burn tyres or used oil, cement producers should apply for a permit to burn 'rubber waste' and 'hydrocarbon residues' respectively, to allow for maximum flexibility.

Herman Weiss of Allgaier started the next session, on processing technology for AF, with details of his company's rolling bed dryer for AF. He pointed out that there must be a good heat exchange between product and drying air, with continuous mixing and breakage of lumps, the possibility of the use of residual energy from other sources and high availability and low maintenance. The rolling bed dryer is a horizontal cylinder open to the top, with an agitator for mixing and product transport, and with drying air injected into the bottom of the vessel (diagram). The dryer cannot easily cope with very large particles, of over 100mm such as logs and chunks of boards, due to the possibility of clogging, and also struggles with very fine particles, which are best dried in other types of equipment such as a dispersion dryer. The higher the temperature of the drying air, the higher the efficiency of the drying process, although fire and explosion limits must also be take into account.

Marcus Brew of Untha UK spoke about developments in shredder technology. Interestingly he pointed out that managing shift patterns of the workers that operate the equipment, as well as running the plant on a two or three shift basis rather than on a single eight hour shift, will lead to the optimised use and faster payback of the equipment. Marcus pointed out that ferrous metals and aggregates in the waste stream are problematic for shredders. However, with a typical metal content in municipal solid waste (MSW) of 3% and a value for ferrous metals of Euro168/t, a 30t/hr waste handling plant can produce around Euro1m-worth of metal each year, making it clearly worth installing a metal separator in the process.

Jori Kaaresmaa of BMH Technology Oy, Finland, next spoke about the Tyrannosaurus Solution for AF. He pointed out that everything that has ever been or will be produced in all of the factories in the world will one day be waste, and that MSW is really the only long-term reliable source of AF for the cement industry. Jori suggested that shredding is the heart of the material preparation concept for AF, since it is the key to accurate separation to produce separate 'pure' SRF and other valuable side fractions. The heart of the Tyrannosaurus machine is a rotating rotor of 'knives,' where waste is shredded against a static chamber also covered with cutting 'knives.' There is 'zero gap' between rotating and static knives, which ensures clean cutting and longer knife lifetime. A 'Massive impact protection system' protects against non-shreddable materials in unsorted MSW.

In an unusual turn, three presenters from three different companies, Yara, robecco and Thorwesten Vent, spoke about their complementary services to help avoid fires and explosions in AF and coal handling facilities. In short, Yara helps to prevent fires and explosions through its inerting gases, robecco can provide monitoring (for CO, CH4, O2, and other explosive gases) and control systems for safe operation, and Thorwesten vent can provide systems that allow for non-destructive venting of any explosion gases through self-reclosing explosion venting devices.

Markus Kaufmann of A TEC Greco started the session on pyroprocessing by speaking about his company's experience in burning AF in kiln burners. Markus pointed out that at high enough injection speeds, particles will essentially stay within the flame for long enough to fully combust - if enough oxygen is available within the flame. He suggested that cement producers should avoid using low NOx burners to burn AF, since they can result in double flame formation, increased free lime and more build-ups. The Flexiflame burner offered by his company is a sophisticated high momentum device capable of firing a variety of AF, with NOx creation control and designed to be 'O2-ready.' Special atomising nozzles can be used to burn 'dirty liquids,' such as those contaminated with fats, for example.

Next, Heiko Schurmann of KHD Humboldt Wedag spoke about a topic close to the heart of all operators - the influence of AF on the clinker burning process, and how it can be affected through equipment and process design. The Pyrojet kiln burner now has a retractable swirl element that can aid in AF distribution within the kiln flame. The Pyroclon calciner can be used in different forms to promote the combustion and higher TSR (thermal substitution rate) of AF in the pyro-line, particularly when used with a combustion chamber which allows the utilisation of difficult to burn fuels such as coarse anthracite, petcoke and coarse AF through its additional residence time at high temperatures. Heiko stated that a number of KHD-provided plants are nearing 100% AF use. He also mentioned the patent-pending Pyroredox gasifying reactor for the drying and gasification of alternative fuels while simultaneously reducing primary NOx, about which we can all expect to hear more in the future.

Mike Hevey of Air Products pointed out that oxygen should not be used as the first resort for any problems in the kiln: kilns should be optimised for all other criteria first of all, through good practice, CFD modelling and perhaps through some capital investments. Once the kiln has been optimised in other ways, then oxygen enrichment can help to provide further benefits. His surprising exhortation was to "Avoid becoming an oxygen junkie!" Mike also mentioned the possibility of cryogenic ultra-fine grinding, using liquid nitrogen as a coolant.

Consultant Xavier d'Hubert advised producers not to consider the burner as a stupid and static machine anymore, but rather that it should be considered as the main control tool for kiln operation. Xavier pointed out that burners have become progressively more complex, culminating, he said, in the M.A.S. burner from Unitherm, which is able to fire a wide variety of gaseous, solid and liquid AF, while producing low NOx and allowing substantial flame control partly through its use of adjustable swirl hoses. Xavier suggested that in fact there is a low influence of injection velocity on flame residence time, and instead suggested that the foremost influence should be the angle of fuel injection into the kiln. This can be achieved with the pneuma-deflector, which uses a portion of the burner's primary injection air to deflect solid fuels upwards at the end of the burner pipe to alter their flight trajectory and burnout potentials.

Matthias Schumacher of aixergee Process Optimisation boldly stated that it is no problem to achieve a 50% thermal substitution rate (TSR), and that the challenge now is to achieve even higher rates. In illustration he reminded delegates that one Cemex plant in Beckum, Germany has had a two-week run using 100% AF. Matthias pointed out that both particle size and shape are important in combustion and flame shape. Use of AF can cause ring formation, brown clinker, off-spec clinker, fluctuating kiln operation, coating and clogging, ball formation and bypass blockages. Matthias stated that every kiln is different, and that each much be treated as an individual: no one solution is applicable to all kilns. Perhaps unsurprisingly, Matthias suggested a process of data gathering and assessment, analysis including conventional mass and energy balance calculations, CFD modelling and thermochemical models, prior to adjustment of process settings, and modifications and retrofits if required.

Maria del Mar Cortada Mut, PhD student at the Technical University of Denmark, then spoke about sulphur release due to unburned AF in the cement kiln inlet. High sulphur levels from either fuels or raw meal or both can lead to blockages and/or corrosion in the calciner and cyclones. In an experimental set-up, Maria showed that smaller combusting particles released higher levels of SO2, and that higher levels of SO2 were produced at lower O2 levels. Sulphur release was found to take place during initial combustion, rather than the later char phase of particle combustion.

Ziad Gabriel Habib of family-owned lime, dolomitic lime and minerals producer the Lhoist Group gave the final presentation at the conference, on combustion and NOx emissions in lime regenerative kilns. He started by saying that the TSR in lime kilns is much lower than in the cement industry, at perhaps 8% rather than at an average level of around 20%. One reason is that around 80% of lime produced is made in shaft kilns, which do not lend themselves to AF use. Many of the uses of lime are for lime's chemical characteristics, requiring a pure raw material feedstock and the avoidance of any contamination during production. Regenerative shaft kilns are comprised of two identical shafts next to each other, which are alternatively heated by fuels injected via burner lances, with downward movement of combustion air which moves through the material bed and thence across to the parallel shaft and upwards towards the exhaust, preheating the material bed as it moves: every 10 minutes the gas flow is reversed, allowing for very fuel-efficient lime production. Biomass is a high-NOx-generating potential alternative fuel for use in these types of lime kilns, but NOx can potentially be reduced by using SNCR.

Conference prizes

At the post-conference prizegiving, A TEC was awarded the prize for best exhibition booth and all presenters were thanked for their efforts. On the basis of delegate voting, Maria de Mar Cortada Mut of the Technical University of Denmark won third place in the best presentation awards for her paper on sulphur release from AF, while Jori Kaaresmaa of BMH won second place for his paper on Tyrannosaurus-based shredding. However, Egmont Ottermann of PPC won first prize for his paper on the use of social networks to promote the use of AF.

Following pre-conference polling of the global alternative fuels community, the 9th Global CemFuels Conference will take place in 2015 in Dubai, UAE. We look forward to meeting you there!

Delegate comments 2014

• Very interesting conference
• Very well organised event!!! Congrats.
• Well done. Thoroughly enjoyed the two days.
• Very good!
• The organisation of the whole event made a very professional impression
• Very good organisation.
• Thanks for your time and your organisation.
• I really enjoyed the event - many thanks for all the planning and organisation.