16th Global CemFuels Conference 2023
20 - 21 September 2023

The 16th Global CemFuels Conference has successfully taken place in Istanbul, Türkiye, supported by the Turkish cement manufacturers' association, Türkçimento. In total there were 205 registered delegates at the event from 41 different countries - a new record for attendees -  as well as 30 exhibitors. The event will next take place in Dublin in September 2024.

(Above: 'Ladies of Alternative Fuels' at the Global CemFuels Conference 2023)

View the CemFuels 2023 VIDEO

View the Global CemFuels Gallery 2023

Short Course

Around 30 delegates took the opportunity to attend the Alternative Fuels Short Course, hosted by Stéphane Poellaer and Michal Hinkel of Alterline, on the day before the start of the conference. Delegates said the following about the course:

• Loved the information: Great crash course on AF - well done!
• Thank you so much for this valuable course
• Extremely insightful and useful, with well-informed presenters
• Really interesting - lots of information

Conference first day

At the start of the conference, Ms Canan Derinoz Gencel gave a welcome to Türkiye on behalf of the Turkish cement manufacturers’ association, Türkçimento. Canan mentioned that Türkiye used around 1.6Mt of alternative fuels in 2022, a thermal substitution rate (TSR) of 10.1%, after using only 47,000t in 2007. RDF and TDF each account for around a third of the supply of AF. Around two thirds of the RDF is of industrial origin, with a third being domestic waste. Türkiye aspires to use the same level of AF as the EU, which is currently at 52%, by 2050 at the latest. The rate limiting factor at the moment is the supply of alternative fuels, particularly biomass, and Canan suggested that local municipalities should be encouraged to establish facilities for processing waste.

Jens Breidenbach of KHD Humboldt Wedag gave the first of the event’s technical presentations. He started with an impressive map showing that the majority of Turkish cement plants use KHD’s equipment, and pointed out that the country has traditionally been an early adopter of new technology. Jens introduced the KHD Pyrorotor, which is a rotating drum that can accept very coarse alternative fuels, up to the size of whole tyres. Tertiary air is fed into the Pyrorotor, which first dries the AF and then pyrolyses the fuel, creating a lean gas which passes to the calciner. The material retention time depends on the variable rotation speed and is up to 10 minutes. The largest currently available version can process up to 50t/hr, and the company currently has 14 case studies either completed or under execution, many of them in South Korea.

Matthias Schumacher of aixergee GmbH gave some details about AF use at Spenner Zement, in particular a project to reduce blockages in the calciner. Using CFD analysis, Matthias showed that stratification, recirculation and overheating had led to the coating formation. The coatings had constricted the calciner, leading to higher gas speeds and reduced retention times. Meal spillage also meant that undecarbonated raw materials could fall into the kiln, which meant that the kiln needed to be ‘over-fired.’ The decision was finally made to replace the calciner during a retrofit project, to provide optimised combustion and to reduce NOx formation. Production was increased by 15%, but heavy coating formed in the kiln inlet, leading to daily cleaning. It transpired that the plant’s very short kiln (40m, the second shortest in the world) meant that a proportion of the main burner lignite fuel was not fully combusted by the time it arrived at the kiln inlet chamber. The plant’s burner was improved to increase turbulence and burnout, and this not only ameliorated the inlet chamber problem, but also allowed the plant to start to use animal meal (meat and bone meal, MBM).

Tim Hamer of Vecoplan mentioned that the easiest way to start to prepare alternative fuels is to use a single step shredder. A further shredding stage will result in a more sophisticated product, allowing for density separation, inerts separation and effective particle size control. Pre-separation of high-chlorine plastics and metals may provide a lucrative byproduct stream.

Luigi Di Matteo, CEO of Di Matteo Group, a German company with Italian heritage, spoke about how to achieve consistent alternative fuels to allow maximum TSR. Di Matteo supplies equipment in all areas of AF use, from reception, storage, processing, conveying, dosing and beneficiation. New diverter gates being offered by the company for pneumatic conveying systems not only decrease the capital cost of the system, but also the pressure drop and thus the operational cost.

Gökhan Keskin of ATS spoke about his company’s AF capabilities, and mentioned some new developments. Firstly, ATS has a new offering of an air floating belt technology, while a belt twisting device ensures that the same belt surface is used each time in a pipe conveyor, optimising wear of the belt. The Twin Doseahorse is a compact dosing extractor which can dose different amounts of AF to two different injection points. Automatic cranes are now equipped with anti-sway technology, a mathematical approach, which reduces crane grab cycle times, while regenerative electrical production is used on the crane grabs as well. Finally, a new image analysis system can assess tyres prior to feeding, to avoid blockages and to optimise feeding rates.

Olaf Michelswirth of Intercem Engineering spoke about two case studies on AF receiving and dosing, one without intermediate storage and one with. At the first, the company had to design a truck receiving station in a very awkward site, which, as Olaf put it, “would not win any beauty awards,” but which has also “worked like a Swiss watch” for two years. In a second case study, with automatic storage and reclaim, the truck receiving station is designed to process fluff for dosing to four different cement kilns on the same site, incorporating a variety of separation stages to further improve alternative fuel quality.

Uwe Maas, ThyssenKrupp Polysius presented a case study describing how a Prepol SC-C type step combustor was successfully installed at Oyak Çimento’s Adana plant. As Maas explained, reaching a higher thermal substitution rate of alternative fuels (AF) on a pyroprocessing line with a separate line calciner (SLC) presents plant operators with a number of challenges including AF/raw material drop out, temperature fluctuations in tertiary air, volume fluctuations and the fact that the tertiary air duct elbow, at the base of the SLC, needs to be cleaned on a regular basis. Oyak Çimento operates a 4500t/day preheater kiln with an SLC extension at the Adana site and encountered these problems. The Prepol SC-C was recommended as it is used to dry and ignite coarse fuels, can be used for higher grade AF and lends itself for retrofit projects where space is tight. Initially upon installation, the thermal capacity was not much higher than the old direct feeding system and high levels of unburnt AF in the elbow and high emission peaks of CO were noted. This was remedied by the addition of a small tertiary air duct branch for defined combustion, as well as meal splitting and the use of computational fluid dynamic (CFD) modelling for additional optimisation. Subsequently, the TSR rate at the calciner rose from 13% to 35% and the mass flow from 4t/hr to 12t/hr. The step combustor feeds mainly commercial and industrial waste into the SLC. Further planned works on the setup include improving the ID fan and drive to increase the gas volume capacity, further reducing the need for cleaning at the elbow, increasing the calciner nozzle velocity and using more tyre chips. Denizhan Kilinc, Oyak Çimento then joined Maas to answer audience questions.

Next, Erwan Godard from Hofmann explained how his company’s AB 9000 Active Balancing System product could be used to rebalance a cement kiln ID fan to reduce shutdown time caused by sulphur build-up due to the use of AF. The system monitors vibrations and can be configured to automatically rebalance a fan once a set threshold has been reached. Notably, the product can do this during operation with no need for stoppage. It accomplishes this through the use of two balancing rotors that can be adjusted via non contact transmission by activation of stator coils. In an example given at plant run by Solusi Bangun Indonesia, vibration peaks of up to 8mm/s were recorded before installation and then reduced to 3mm/s subsequently. The intention is to reduce the need to stop a kiln’s ID fan for cleaning. After the presentation an audience member noted that fan shape and kiln chemistry also play a major role in the build-up of debris on a kiln ID fan.

Eugen Becker of Eggersmann Anlagenbau GmbH discussed how his company uses mechanical biological treatment (MBT) to convert municipal solid waste (MSW) into refuse-derived fuel (RDF). After presenting an economic case for MBT, he talked about his company’s Teuton ZS 50/ 55 slow speed shredder for pre-treatment, with a capacity of 45t/hr, and above 50t/hr with MSW. Then he detailed how the company’s RDF production plant in Sulaymaniyah, Iraq, uses the Convaero Bio-Dry product, a membrane-covered system for composting and biological drying of MSW. The site uses 21 lanes to reduce the moisture content of MSW from 52% to 20% in 20 days, with one lane turned per hour by use of the Backhus Con 60 turner. Material from pre-shredding is moved by trucks or wheel loaders to refinement at the site. Later, low calorific fractions are removed in refinement, with fine shredding to 50mm and the option for size fractions at 30, 60 or 80mm. Subsequently, audience questions centred around the viability of converting MSW into RDF.

Global CemFuels Awards 2023

After the first day of the conference, delegates enjoyed a lively dining cruise along the Bosphorus, during which time the Global CemFuels Awards were presented. Nominatoins can be made by anyone in the industry, and are subsequently voted on by industry participants. The outstanding AF project award went to ATS for work at the Medcem plant’s storage and feeding line, while the AF-using company of the year award went to OYAK Çimento - a popular choice. WKE (Waste Knot Energy) received the prize for AF-supplying company of the year, and ‘most innovative technology for AF use’ was presented to A TEC for its Rocket Mill. The award for ‘outstanding contribution to the promotion of the use of alternative fuels went to Türkçimento,’ the association of Turkish cement manufacturers.

Three attendees were presented with ‘Personality of the Year’ awards - catching up after Covid; Michael Suppaner of A TEC; Enrique Rozas of Drake Cement and Karel Jennissen of N+P International - worthy winners all.

Second day

The second day of the conference was started by Ahsan Anis from Power Cement of Pakistan, who pointed out that there is no separation of waste at the domestic level in the country, so that MSW is a very poor prospect for fuel, since it is totally mixed, with food waste and other waste mixed. However, Pakistan is a very major agricultural producer, albeit with much of the waste burned in the fields. Wheat, rice and maize waste are all burned in the open and Ahsan suggested that if they could be collected, they would make good biomass fuels. Power Cement has started to use sugarcane press mud, left after sugar filtration, which has a CV of 3000-3500kCal/kg on a dry basis. The ‘mud’ has a moisture content of up to 45%, so it must be air dried before use.

Christian Ortkras of Westeria next spoke about his company’s capabilities in alternative fuels, including wind-sifting machines, spreading machines and conveying solutions. Fine dosing of AF can be achieved with a veritable daisy-chain of walking-floor receiving stations, a steep tumble conveying belt with height adjustable stripping wheel, a weigh belt feeder and air-supported conveyors. Christian mentioned the use of palm kernel shells (PKS) at a cement plant in Nigeria, which are fed at a rate of 30t/hour, and which have a density of 0.6t/m³ and high calorific value, but which can be abrasive on machinery.

Michael Hinkel and Stéphane Poellaer of Alterline next spoke about the key steps for successful AF implementation. “Typical failures of AF projects can be avoided by a systematic and pragmatic approach based on experience and training of staff.” Stéphane mentioned that clients still rely on a lot on ‘natural intelligence,’ the human brain, to make decisions, which was a nice contrast to the many other presentations that mentioned so-called ‘artificial intelligence.’

Lars Jennissen of N+P Group explained about his company’s AF production approach, which is applied to N+P’s 670,000t/year production capacity. “Our metal extraction needs to be good, because you do not want to have metals in your pellet press,” he started. The company now uses live near-infrared analysis to infer CV, moisture content and chlorine content, so that formulations can be adjusted in real time. Lars mentioned a PAF pellet (pulverised AF) which can be milled into a finer final fuel.

Joana Bretz of TRIE Engineering next spoke about achieving the least fuel cost though the use of AI, using the example of a Brazilian cement plant. The plant was using petcoke with 7% sulphur (!) as well as a variety of AFs with low to very high chlorine contents. It took a day to receive the results of testing of each lorry load of AF, so that the plant was effectively ‘flying blind.’ Joana detailed a computerised system that took into account 2000 variables, including fuel costs and CV, as well as the heat balance of the system. The system allows analysis of various ‘what-ifs?’ of fuel mixes, and their likely effects compared to key production goals. These are presented to the control room staff for their decisions. The next step would be to use the system’s conclusions in the plant’s expert system, to automatically choose the fuel mix.

Jan Tuma of Beumer Group Czech Republic started off by saying that a reliable gravimetric feeder is the heart of every alternative fuels system. Beumer offers a series of ‘Optifeed’ gravimetric weighfeeders. The latest OptiFeed B is a belt weighfeeder, with a completely enclosed cleated belt which allows the feeding of coarse 3D materials of up to 250mm, at up to 35/hour, without risk of blocking or winding with 1D tapes, and at an accuracy of +/-1%. Alternatively, a screw conveyor may be used in case of fine materials. Three such units have been sold to the Oxyfuel pilot project at Mergelstetten in Germany, with commissioning in 1Q24.

Berthold Bussieweke from Thorwesten Vent and Carsten Pries from robecco next spoke on explosion protection concepts for AF. Berthold started by saying that nowadays, the hinged baffleplate used as a venting device is fabricated from carbon fibre to make it as light as possible. The self-reclosing devices then prevent the ingress of oxygen to avoid ongoing fires, as well as preventing the leakage of CO₂ or nitrogen inerting gases. Carsten pointed out that highly dried sewage sludge presents the same risk of fire or explosion as lignite, especially since self-heating of sludge may end with self-ignition by biological processes. For an explosion to occur, you need a fuel, oxygen, an ignition source, a particular dust concentration and confinement: robecco  seeks to avoid any explosion through continuous monitoring and through the replacement of the oxygen source by purging with nitrogen or CO₂.

Ondrej Kozel of Schenck Process Europe then gave delegates details on alternative fuels feeding, using the MultiFlex gravimetric weighfeeder. New innovations - particularly the use of a flexible screw - will increase the accuracy of the weighfeeder to +/-0.5%.

The penultimate presentation was given by Michael Suppaner of ATEC who reminded delegates that even if Germany is at a TSR of 80%, India is still at 3%. Why this big disparity? He said that in his home country of Austria, households have to pay to have their waste collected, with the money going to the waste processor, and the cement plant then gets paid to burn the resulting alternative fuel (Euro65 - 100 for low quality RDF, Euro10 - 40 for burning high quality SRF). Even if they lose some production from AF use, the cement companies receive a very attractive RoI. However in the USA for example, the focus is on returning value to shareholders, so that longer-term investment in equipment to be able to use AF is not prioritised. In addition, generally, politicians are not willing to lose votes for instituting laws to outlaw landfilling and to potentially institute a tax on waste disposal. “Only politics can change this situation!” Michael showed figures that indicated that at nearly any level of TSR, the use of AF will make money for the cement producer. A TEC can help to make it happen, perhaps with a Rocket Mill, which can reduce AF to a fluffy high-surface area fuel, suitable for firing into even a short-residence-time calciner.

Petro Cella of Entsorga was the final speaker, and he spoke about mechanical biological treatment of MSW, which can lead to a reduction in moisture content of 30-40%. He said that the technology for a project must be proven and bankable (“No problem”). He described a project in Indonesia (population 300million), which has taken 13 years to come to fruition. The project by Indocement was for storage, feeding and dosing of SRF, and was one of the first for alternative fuels in the country.

Farewells and prizes

After the conclusion of the conference programme, delegates enjoyed a sunset reception overlooking the Sea of Marmara, where the conference prizes were presented. Based on voting by the delegates, Michael Hinkel and Stéphane Poellaer of Alterline received the prize for third placed paper, while Joana Bretz of TRIE was awarded second prize for her presentation on optimising the fuel mix. A surprised Michael Suppaner of A TEC won the prize for the best presentation for his speech on why AF usage varies so much around the world, and how the numbers can be improved.

Delegates rated the event very highly for its technical content, networking and business opportunities, as well as for its organisation and time-keeping. As one delegate said, after marking the event as ‘Excellent’ in every category on the delegate survey, “Really the best conference I have attended ever. Thank you very much!”

The 17th Global CemFuels Conference on alternative fuels in the cement and lime industry will take place in Dublin in September 2024.

Below: Serial winner Michael Suppaner of A TEC in full flow at the conference...

11th Global CemFuels Conference 2017
2 - 3 February 2017

The 11th Global CemFuels Conference & Exhibition has successfully taken place in Barcelona, with 185 delegates from 37 countries attending.

View the image gallery from the 11th Global CemFuels Conference & Exhibition 2017 (large gallery - may take time to load)

By Robert McCaffrey, conference convenor

The conference started with a presentation from Michele Graffigna from HeidelbergCement, who gave some details on the Italcementi acquisition and the use of alternative fuels (AF) in the combined group. Due to the acquisition, HeidelbergCement created a new Mediterranean region with 19 plants. Spanish landfill costs are still low, but around 50% of waste is handled by MRF plants all the same. Countries like Morocco show great potential, with a large cement sector and relatively low AF usage age. However, the first shipment of refuse-derived fuel (RDF) from Italy was stopped at the port and import of waste-derived fuels was banned. This has led to a greater effort to create RDF from local waste. On the other hand, the fuel crisis in Egypt in 2013 drove the whole sector towards the use of alternative fuels. The Kattameya waste treatment facility was the first to be based at a cement plant in Egypt and other projects have driven AF use in HeidelbergCement plants in the country.

The second presentation was given by Joe Harder of OneStone Consulting, who spoke on global trends in AF. He pointed out that a huge range of AF usage rates exists through the industry, from plants burning no AF to plants that can and do use 100% AF substitution. Joe stated that in Europe the thermal substitution rate is around 39%, whereas in North America it is only 5%. In the Netherlands the rate is around 85%, down to 23% in Spain and only 7% in Greece. China’s rate is currently 2%, but is said to be rising fast. The use of AF in Germany has plateaued at around 60%, partly due to economics, partly due to supply and partly due to technical issues. Due to its purchase of selected assets from Lafarge and Holcim, the Ireland-based CRH is now the world’s leading cement producer in terms of AF use, with a company-wide thermal substitution rate (TSR) of 39%, followed by Cemex on 26% and HeidelbergCement on 21%. Generally producers in developing countries use a higher proportion of biofuels - which Joe Harder suggested should be secondary byproducts, rather than being specially produced since these crops will compete for land and resources with food crops. The coal price is not tied to the oil price, stated Joe, and since the summer of 2016 the price of thermal coal has started to increase again after five years of steady declines, leading to an increase in interest in the use of AF. Joe pointed out that Geocycle, established in the 1970s by Holcim, now operates in more than 40 countries and has over 2000 employees. This is a model that other cement companies could usefully copy and try to improve upon. Dr Harder suggested that a number of cement companies have set challenging targets for AF use, some of which are challenging enough that they are unlikely to be met. Coal and petcoke prices, availability of AF and cement capacity growth, and the availability of pre-treatment facilities will be major criteria for the future development of the use of AF.

Andy Hill next gave a presentation with a very short title, ‘EU AF,’ but which Andy described as a huge topic. An increase in immigration into Germany has led to an increase in production of waste and an oversupply of SRF, while Russian bans on cement imports and Indian demonetisation have also led to pressure on SRF prices. Other uncertainties are Brexit, the rise of Donald Trump, and China’s sustainability push. China’s ‘Green Fence’ policy is increasing quality control on imported waste and may eventually lead to the end of waste imports. There is a global oversupply of waste at the moment, so a Chinese ban would strongly impact on prices and profitability elsewhere in the industry. On the other hand, Europe currently ‘loses’ around 600Mt of waste each year to landfill that could be used as fuels and for other uses. Around 30% of municipal waste still ends up in landfill, although there is a 2030 target of only 10%, EU-wide. An extension of ‘Extended producer responsibility’ legislation should lead to more inherently recyclable products, and a reduction in supply for RDF. At the same time, competition from the waste-to-energy (WtE) sector is likely to increase. CO₂ prices are likely to increase, possibly to Euro40/t, by 2030, although the European cement industry may cease to be competitive at a rate of around Euro20/t. Plastics production will continue to grow worldwide, while paper recycling is at a high level already. The bulk of recycled paper is shipped to China, but again, higher quality barriers may decrease the amount admitted to China in the future. RDF has a CV value up to 15MJ/kg, while SRF has a calorific value (CV) of above 15MJ/kg and is generally a highly processed ‘engineered’ fuel. Andy said that the market for SRF worldwide is around 60Mt. SRF is increasingly being pelletised, meaning that it can then be more easily co-processed and incinerated with coal. Freight rates are starting to rise again from historic lows, with price increases also being seen in container rates. Andy suggested that oil prices are now unlikely to rise above $75 per barrel due to the impact of American drillers.

Vagner Maringolo of Cembureau next spoke about opportunities for increased waste take-up for the European cement industry. Vagner points out that the EU is moving towards a ban on landfilling for municipal waste, which will give a strong boost to the supply of alternative fuels. A Cembureau/Ecofys study on the market potential of AF brought up a number of interesting conclusions. Around 10Mt of waste was co-processed in cement kilns in the EU28 in 2015, representing around 2% of total combustible waste each year, but representing 10% of all of the energy recovery from waste in the EU.

Jaime Ruiz de Haro, president of Cemex Spain and president of Oficemen, the Spanish Cement Producers’ Association, next spoke about the development of AF in Spain. Average cement consumption in Spain in the last 50 years was 25Mt/yr. However, consumption spiked to more than 50Mt in 2007, and has plummeted to just over 10Mt in 2016, a demand level last seen in the 1960s, precipitating a huge crisis in the cement and construction industry. Spain is the largest exporter of cement and clinker in Europe. In Spain, 29 of the 33 Spanish cement plants are authorised to use AF, and 77 types of waste have been authorised for use in Spain. The tonnage of AF used in Spain has plateaued at 700 - 800,000t/yr for the last five years, at a TSR of around 24%. RDF is the mostly widely used AF, at over 250,000t/year, followed by tyres (100,000t), biomass and animal meal. De Haro pointed out that high disposal fees strongly drive the use of AF in the cement industry, and he suggested that stronger implementation and enforcement of regulations and fees will be the main driver of increased AF use in the country. In Spain a realistic target has been set to use 30% TSR by 2020, 45% by 2030, and 70% by 2050.

Mrs Dalia Sakr of the International Finance Corporation spoke about the use of AF in Egypt, starting with the energy crisis of 2013 when gas supplies were diverted from the cement industry to the power industry. This caused a fall in production of 50% and this caused the industry to move strongly towards not only increased use of coal but also increased use of AF. Mrs Sakr introduced a major study of potential sources of AF in Egypt, including RDF, agricultural waste, dried sewage sludge and tyre-derived fuel (TDF). Agricultural waste is the largest waste stream of more than 30 - 35Mt each year, but production is geographically widely spread and the material has relatively low CV. Each year Egypt generates more than 21Mt of municipal waste, forecast to reach 35Mt by 2025. At the moment only around 0.5Mt is used each year, but the best case scenario would be to use around 5Mt/year. Around 1Mt of sewage sludge is produced each year, but a major challenge is to reduce its moisture content to economic levels. The amount of tyres produced each year is estimated at around 300,000t, but only 10% of this amount is used by the cement industry. On the AF demand side, the Egyptian cement industry has a TSR of only around 7% but the majority of cement plants in Egypt have active plans to start to use or to use more AF in the next five to ten years. One of the main problems is that a gigajoule of energy from AF is not appreciably less expensive than energy from coal or petcoke. The quality and security of the supply is also an issue, and Mrs Sakr stated that regulatory support will be required to improve the quality of waste-derived fuels. As in other countries, the enforcement and increase in tipping fees will strongly drive the availability of AF in Egypt.

In the event’s next session, on alternative fuels production advances, Daniel Wresnik of Untha spoke about new trends in SRF production. Daniel suggested that a strong trend in the industry is towards single-step shredding. He introduced several completed projects including Geocycle projects in Vietnam, the US and Mexico. Requests from the industry led to the company to develop the XR mobil-e mobile shredder. Both the mobile and stationary shredders use slow-running single shaft shredding for rough, medium and fine shredding of waste.

Next, Eric Plantié of Precimeca introduced the tyre-shredding capabilities of his company, which include both stationary and mobile tyre shredders. The company has striven towards clean-cut and homogeneous size of chips as well as a consistent output through the lifetime of the knives and no exposed beading wires that could lead to the clogging of the dosing system. Tyre supply is not prone to seasonality of supply and offers 25 - 30MJ/kg (6-7000kcal/kg), allowing nearly 1:1 substitution by weight with coal or petcoke. TDF has a bulk density of around 0.5t/m3, is almost incompressible and can be stored outside with no ill-effects. TDF has a chlorine content of <0.1%, and sulphur content of less than 1.5%, making it a relatively easy-to-use alternative fuel. Eric mentioned a case study of a LafargeHolcim cement plant with a TSR of 60% using 70,000t of AF, of which 3000t is whole tyres and 15,000t was imported tyre chips of inferior quality. The plant specified that, instead of using imported chips, a new tyre shredder would have to produce 10t/hour of clean cut product, at a particle size of lower than 50mm. The plant settled on a fully-automatic stationary tyre shredder with two high-torque low-speed shearing rotors, capable of accepting tyres up to a maximum diameter of 1200mm. The rotors will automatically reverse rotation direction to prevent any potential jam. The system includes a tyre chip classifier to ensure that all output is of below 50mm chip size.

Neville Roberts of fuel-producer N+P next spoke on the subject of SubCoal SRF pellets. N+P has a reference plant at Delfzijl in the Netherlands for SubCoal production, and pellets have been shown to be hydrophobic, while being capable of being co-ground with coal. SubCoal has a CV of 23.8MJ/kg, and can be transported in containers, with no de-baling required at the end user, unlike some other types of AF. Loesche vertical roller mills and Atritor grinding systems have both been used to grind SubCoal pellets. N+P is busy setting up SubCoal production facilities closer to a number of cement industry users around Europe, including a new Euro14m 120,000t/yr production plant at Teesport, near Middlesborough in the UK. SubCoal pellets from the plant will have moisture content of less than 8%, with CV of more than 20GJ/t, with the majority of the output of the plant destined for export, not just to the cement industry.

The first presentation in the next session, on AF handling storage and dosing, was given by Juan Jose Riesgo of FLSmidth Pfister on the AF system at the Cementos Portland Valderrivas Monjos plant, which had been visited by delegates the previous day. Juan mentioned some pieces of equipment that can be supplied by FLS that can aid in the use of AF, including Feedex waste storage and handling, the Koch pipe conveyor, the Pfister Rotor weighfeeder, the Hotdisc AF combustor and the Jetflex burner. The company’s equipment is capable of coping with both dense and light AF, down to 0.05t/m³. In fact at Monjos, the company, with partners, built a flexible waste reception, handling, mixing and dosing facility capable of handling a wide variety of AF, including petcoke, RDF, MBM, dried sewage sludge (DSS) and wood. Juan mentioned some useful experience from the project; RDF needs to have a moisture content of less than 30% to avoid handling problems; chlorides need to be lower than 2% to avoid pyroprocessing blockage issues; the fat content of MBM needs to be lower than 16% to avoid it sticking to walls; wood had issues with self-combustion after fermentation in hot weather and turned out to be non-economic. Truck unloading should be done carefully to avoid spillages, while wear issues can be found in pneumatic pipelines and in the weighfeeder when using certain types of AF. Silos for the storage of AF should be shorter and wider than normal, just the opposite of silos for storage of traditional fuels. It has been found that the average maintenance bill for the full AF system, including spares, service and manpower, is in the region of Euro100,000 per year.

Global CemFuels Awards Dinner

The Global CemFuels Awards Dinner took place at the UNESCO-listed Recinte Modernista de Sant Pau, close to the Sagrada Familia in Barcelona. The ‘outstanding AF project’ award went to HeidelbergCement’s Lengfurt cement plant in Germany, which burns 100% AF, while HeidelbergCement itself won the award for ‘global AF-using company of the year.’ N+P of the Netherlands won the award for ‘global AF-supplying company of the year.’ The ‘most innovative technology for AF’ prize was awarded to Lindner-Recyclingtech’s Polaris single-shaft shredder; ‘project manager of the year’ was awarded to Marco Mater of AVE, Portugal, and the award for outstanding contribution for the promotion of AF was presented to the CEMA Foundation of Spain. The award was accepted by Jaime Ruiz de Haro, president of Cemex Spain and president of Oficemen, the Spanish Cement Producers’ Association. The Global CemFuels ‘personality of year’ award was presented to the widely-admired 90-year old industry stalwart Sebastian Rosin of Atritor Ltd. It was announced to acclaim that the location of the 12th Global CemFuels Conference will be Berlin.

Conference second day

On the second day of the conference, Michael Gramling of MHC Engineering Fördertechnik GmbH started by giving details of an innovative drag chain conveyor design for space-constricted cement plants. He pointed out that the wide variety of physical characteristics of AF in terms of density, moisture, stickiness and particle size distribution and shape means that they are much more difficult to handle than classic cement-making materials such as limestone, gypsum and clinker. Michael Gramling went through the advantages and disadvantages of inclined belt conveyors, inclined sandwich conveyors, inclined chain conveyors, bucket elevators and vertical chain conveyors, concluding that the vertical chain conveyor offers strong advantages for conveying AF in a space-constrained cement plant.

Basri Ogut of the ATS Group next gave some details of case studies of handling AF in the cement industry, including two case studies at Ultratech Aditya Cement in India and Cimat Beni Mellal in Morocco. Basri introduced an extraction and dosing machine named the Doseahorse, incorporating AF extraction and dosing in the same machine.

Luigi Di Matteo of the Di Matteo Group next pointed out that the coarser particle size of AF means that devolatilisation is slower, ignition is later, burnout needs more residence time and unburned particles may fall into the clinker bed. He went on to outline his company’s wide capabilities in manufacturing equipment to handle, dry, dose and feed AF.

The final paper in the session on handling, storage and dosing was given by Jose Diaz of Schenck Process Europe, specifically on dosing technology for AF. He mentioned the MultiFlex compact closed AF weighfeeder and the MultiDos belt weigh feeder, for a feed rate of 1 - 30t/hour. The weigh feeders can be used in conjunction with a novel swirl air chamber for calciner feeding.

A pair of papers on the influence of AF on clinker quality were up next, the first of which was given by Stéphane Poellaer of Alterline. He stated that to be able to start to use AF, the first prerequisite is for preexisting stable operation in the kiln and pyroprocessing system. Stéphane suggested that AF feeding should first be tried at the calciner burner, being the most ‘forgiving’ point of feeding, before moving to introduce AF at the main burner. Lumpy fuels that cannot be suspended in the gas stream in the calciner can be problematic. High alkaline contents of AF will lead to innumerable problems, including corrosion, refractory expansion, thermal shocks, ring formation and blockages. AF will also affect the flame temperature and shape, while clinker quality will be affected in a number of ways, including by the ash content of the AF. He suggested that each tonne of AF fed to the system will reduce the clinker output by two tonnes, unless systematic steps are taken to mitigate the deleterious effects of AF combustion. He concluded that “AF does not make life easier, but it makes life more interesting.”

Carmen Gheorghe of Geocycle (Romania) went on to describe a study of clinker and cement produced with and without use of AF, using a variety of analytical techniques. Certainly, the overall chemical composition is not influenced by AF use, while at the same time the mineralogical composition is also more or less unchanged, albeit with more C3S and lower free lime in the AF sample. Porosity is slightly increased in AF-produced clinker leading to a marginally more grindable clinker. Carmen suggested that 7 and 28 day strengths of mortar cubes were also very similar.

In the conference’s final session, on combustion optimisation, Xavier d’Hubert of Nexa Industries gave an overview of burners for rotary kilns. Xavier suggested a threefold categorisation of burners into fixed multi-channel burners, burners that mix or separate the axial and radial primary air inside the burner, and a third category of burners with axial primary air jet ejection angles that are adjustable. He suggested that there has been a general trend from low NOx burners towards burners that are capable of firing a variety of solid alternative fuels.

Matthias Schumacher of aixergee Process Optimisation next spoke on a novel approach to answering the question ‘what particle size is RDF?’ Lumpy fuels may be subject to ‘rain out’ segregation from the burner flame in the kiln, causing unstable kilns and leading to reducing conditions in the clinker bed and yellowish or brown clinker. Rain-out can also happen in the calciner, despite high gas velocities, causing coatings on the shelf and balls in the kiln. Milled coal is of practically spherical shape, with homogeneous and constant particle density, whereas waste derived fuels have a vast number of variable physical parameters, of which particle size is just one. Particle shape and material density are also factors which strongly affect pneumatic transport properties and performance in the flame. Particle shapes of RDF will include flat, cuboid, cubic, and ‘spherical’ (but of very low density, like a ball of wool), with these shapes increasing in sphericity. Matthias suggested that a ‘particle sifting velocity’ distribution should be used, which finds the air velocity required to suspend the different particles, to describe the behaviour of particles in the pyroprocessing system.

The penultimate presentation was given by Joel Maia of FCT GmbH, on a case study at Urmia cement in Iran. The company found itself priced out of the fuel oil market and was obliged to use natural gas. However, the emissivity of a natural gas flame is lower than a fuel oil flame and is at a lower temperature, which brings process challenges, including a higher exhaust gas volume for the same thermal power, higher CO, a lower calcination degree at the calciner exit and higher temperature at the top of the preheater tower. The suggestion was that the plant might purchase four new calciner burners, but it was decided that a CFD study should be first undertaken. It was found that burning natural gas in the calciner with burners in the existing situation would lead to nearly 2% of the gas not being burned within the calciner, with the remainder existing as CO, and this was deemed to be unacceptable. It was decided to add two gas combustion lances into the top of the tertiary air duct, and this was shown to improve the velocity profile and the temperature distribution, leading to better refractory lining protection, better heat transfer to the meal and better ignition of the natural gas. It was also shown that the previously proposed calciner burners would not have solved the problem.

The closing keynote speech was given by Ed Verhamme, who proposed ‘Twelve and a half’ principles of a money-making strategy for the use of AF. His principles were as follows: know the basics of waste management and adhere to the waste hierarchy principles; know the waste and resource markets and value chains; make a weighted decision as to where to enter the value chain; recognise the differences between the waste and cement businesses; lobby for the co-processing of waste resources; get flexible environmental permits; use flexible pre-processing equipment; know the cement process and effects of AF on the system; set realistic technical and economic cement and AF goals; get the backing of senior management; develop long term contracts; and develop a shareholder engagement plan. Finally, he concluded in his twelve and a halfth principle, that you should celebrate your success with everyone involved.

Conference Farewell and prizes

At the conference farewell reception, a number of prizes were awarded. Grupo SPR won for ‘best exhibition stand.’ Carmen Gheorghe of Geocycle was in third place in the best presentation awards, for her paper on the affects of AF on cement and clinker quality, while Stéphane Poellaer of Alterline was in second place with his paper on the impact of alternative fuels on kiln process. However, in first place, and winner of the ‘best presentation award,’ was Xavier d’Hubert of Nexa Industries, with his paper on burner choices.

The conference was strongly rated by delegates, especially for its technical content and usefulness for making contacts. Attendees agreed to meet at the next Global CemFuels, in Berlin.

Delegate comments on the Barcelona CemFuels Conference 2017:

• I would just like to congratulate you for the perfect organisation of Cemfuels conference last week. I think this is one of the best conferences in cement worldwide, because there is a good number of clients, the presentations are more technically-oriented and people who attend it are really interested to learn something new and interact with us suppliers.
• I would like to thank you for the conference. It was really important to me to attend and I am really satisfied of everything. Lots of new contacts and new information on the world of alternative fuels. Your organisation was really perfect.
• It is very well organised
• Thanks, a brilliant organisation - Congratulations!
• Very good conference, I am happy having been part of it
• Good networking opportunities
• Excellent conference
• It was my first CemFuels Conference - it was very useful and I thoroughly enjoyed it
• Keep up the good work. It's the event not to miss!! :-)
• Thanks for the organisation and see you next year
• I have enjoyed the conference very much
• Great conference. Your standards keep improving. Very impressive.
• Plant visits very good
• The organisation is better each time I come, getting close to perfect!
• It was a really good conference, nothing at all to complain about
• Targeted conference, well organised
• Good balance of attendees
• Compliments to the organisers, thank you.
• Thanks for your super efforts to organise and gather all interesting contacts.
• Thank you very much - it was a wonderful event
• I have been in oil & gas, chemicals & petrochemicals and now cement for 34 years, attending a lot of conference everywhere. Must admit that this conference tops them all in all aspects, so Thank You.

12th Global CemFuels Conference 2018
20 - 21 February 2018

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The Global CemFuels Conference has successfully taken place in Berlin, with 160 attendees from 30 countries, 31 exhibitors and 20 presentations. The conference covered all aspects of alternative fuel use in the cement and lime sectors. The 13th Global CemFuels Conference will take place in February 2019 in Amsterdam, Netherlands.

Frank Brannvoll of Cembureau kicked-off the conference with a panoptic overview of the global fuels markets. In the EU28, the thermal substitution rate (TSR) is 43% on average, with around 11Mt of alternative fuels (AF) used each year. Frank pointed out that many countries are below average, with a small number of large countries (Germany, France, UK) at above average TSR and with many countries, notably Ireland and Italy, with huge potential for increased AF use. Frank pointed out that when the US dollar is weak, then fossil fuel energy costs are generally lower in non-dollar local currency terms. This means that the strength of the dollar has a big effect on the choice of fuels used worldwide in the cement industry, particularly with regard to the fossil fuel/AF mix. He suggested that OPEC has decided that US$60-70/barrel is a level that they can ‘live with,’ which is just as well, since as the oil price rises above this level, the Americans can bring more shale gas rigs on line to take advantage of the higher prices, naturally capping global energy prices. Frank Brannvoll also pointed out that Chinese coal consumption dwarfs all other coal markets on the planet, but that the Chinese authorities have been trying to exert greater control over the industry and over pricing: mines have been closed or are now more highly regulated, while there has also been a clampdown on coal price speculation, in order to bring coal prices into a preferred price range. However, coal is trading at above the preferred range and the authorities have now stipulated a maximum price (of RMB750/t, US$118/t). Globally, petcoke prices are strongly correlated with coal prices, but at a discount (otherwise industrial users would just use coal). India has partially banned the use of petcoke, on environmental grounds. There is normally a US$10/t spread between 4.5% sulphur and 6.5% sulphur petcoke. “Higher prices for petcoke mean shorter payback periods for AF projects,” concluded Frank Brannvoll.

The next speaker was Andy Hill of SUEZ Recycling and Recovery UK Ltd, who started off by saying that Brexit will not have a major effect at its start date in March 2019, but that uncertainty is a crucial factor, particularly over the future trading situation and the imposition of tariffs at borders. Andy pointed out that RDF is a lower calorific value fuel, whereas SRF is more highly processed and has higher calorific value. Andy pointed out that environmental taxes have been implemented around the world, but that there is a long way to go to complete coverage. The EU ETS has not been a success so far, with the CO2 price languishing at under Euro10/t for years. However, the EU ETS Phase 4 is forecast to raise the level to beyond Euro20/t (at which point European cement becomes uncompetitive) to as high as Euro40/t. The Chinese, for environmental reasons, are closing coal, cement and steel plants and are banning the import of many categories of recyclables. This has created massive bottlenecks in European recycling flows. Alternative markets (Turkey, Malaysia, Vietnam) have also pushed up prices and quality standards: “It’s a buyers market.” Andy suggested that this might signal the ‘death’ of co-mingled municipal waste collections, in order to force up the quality of waste and recycling streams. In the meantime, there will be a greater volume of RDF and SRF, with price implications for buyers. In the medium term, there is likely to be a marked change in consumer behaviour which will drive recycling flows.

André Van Steenberge next spoke on behalf of HeidelbergCement and pointed out that the company has a target TSR of 30% worldwide. This target has already been met in Europe, but is at only 10% in North America, only 7% in Africa/Eastern Mediterranean and only 3% Asia-Pacific. New management initiatives have been put in place worldwide in order to push AF use, including a dedicated board member. André pointed out that although some AFs are common around the world, others are more local, such as rice husks, so that development of local markets for AF streams will be critical. André pointed out that Italcementi was more advanced in some areas when HeidelbergCement took it over and the combined group has learned from the purchased company in order to roll out best practice. For every waste stream that the company is contracted for, there is always a Plan B,’ and sometimes plans C, D and E, for alternative destinations and users for each material if the first plant cannot accept the material. André suggested that the Chinese ban on impure recycling fractions will lead to a greater requirement for better sorting and that this sorting process might happen in Asia, rather than in the higher-cost EU. Again, less intensive use of plastics is the likely final outcome.

Ed Verhamme of Alternate Resource Partners next gave a global overview of AF trends. He suggested that AF has the potential of abating 750Mt of CO2 per year by 2050 if current trends continue. If all EU countries had a 60% TSR, 26Mt of CO2 emissions would be avoided each year, 15.Mt of waste would be processed, 11.1Mt of coal use would be avoided and Euro12bn of investment in Waste to Energy plants could also be avoided. Ed suggested that global coal production peaked in 2013-2014 and has been steadily declining since then, but that there is still strong underlying demand, for instance from India. A ban on landfilling, or at least strenuously applied and punitive landfill taxes, will strongly encourage both recycling and the development of a supply of waste-based AF. Southeast Asia and Central America are among those areas with the greatest potential for increase in use of AF. In the longer term, Africa is almost totally undeveloped.

Hansjörg Diller next spoke for MVW Lechtenberg, on how to improve quality of alternative fuels. “Quality management always starts at the source,” suggested Hansjörg. At the RDF plant, the incoming waste must be fully characterised. Different categories of waste must be stored separately and any foreign objects must be pre-sorted and removed. Sampling and continuous analysis of waste and product characteristics must be performed and action taken on the results. Materials that are considered to reduce RDF quality should be excluded from AF production, including chlorine-containing and heavy metals-containing materials, as well as those materials with high moisture content and low calorific value. Specific and systematic methods have been stipulated to try to ensure reproducible and representative sampling methods, but with such inhomogeneous materials, this can be difficult. The RDF producer should make a declaration of the composition of the RDF at regular intervals, perhaps after every 1000 or 4000t produced, including stating the measured limits on minor metals, sulphur, chlorine, moisture content and CV of the AF. In such a case, the recipient of the fuel can accept or reject the shipment of AF.

In the next conference session, on case studies in AF, the first speaker was Matthias Mersmann of aixergee Process Optimisation, speaking on the successful optimisation of a secondary-fuel-fired calciner. The calciner in question had fall-out of material in the TAD ‘knee,’ coatings and blockages in the bottom stage cyclones and frequent CO peaks. The plant wanted to safely combust up to 100% of AF in the calciner and at the same time to increase production by 200t/day, while fitting into the same space and reusing the existing ID fans. Trial-and-error can be used to determine the correct engineering approach, but the smarter method is to use a model-based approach, using a virtual model of the process. Matthias pointed out that the complete characterisation of the RDF is critical, in terms of particle shape, density, calorific value and burn-out behaviour, in order to be able to correctly model the process. Matthias showed that a ‘pumping’ or periodic purging of material from the calciner in this case was unavoidable due to the calciner’s design, leading to localised reducing conditions and breakthrough of CO-rich gas into the preheater, as well as a carry-over of unburned fuel into the cyclones which led to coating problems. A redesign of the calciner was simulated and perhaps unsurprisingly the most expensive suggested option was found to be the most effective solution, involving slimming the calciner and the introduction of a longer goose-neck. During a six-week kiln stop the designed solution was enacted and as a result, all process aims were met.

Michail Akritopoulos of Cinar Ltd next spoke on calciner upgrades to burn 100% AF and petcoke. Michail pointed out some of the unavoidable side effects of the use of AF, including an increased heat consumption and to a certain extent, a reduction in production rates. He pointed out that there is a limited potential for thermal substitution on the main burner, of around 40%, whereas on the calciner burner the TSR can be up to 100%: larger particle sizes can also be used in the calciner due to the longer residence times. Due to the wide variety of configurations of precalciners, calciners, preheaters, goose-necks, TADs, burners and other process parameters, each case must be scrutinised separately and a custom-solution applied and Michail gave a number of examples of successful calciner upgrades. He gave some details of the Polysius Step Combustor, as well as the FLSmidth Hotdisc, both of which can be used to combust bulky alternative fuels. AFS ‘skewers’ can be used to burn whole tyres, while the ‘compact calciner’ from PMTEchnologies has also successfully been used to improve AF TSR rates.

Taís Mazza of Loesche GmbH next spoke on an integrated approach to maximise the use of AF in cement plants. Countries in the OECD are responsible for 44% of the world’s waste, but the greatest future increase in waste production will be in poorer Asian countries. Taís suggested that a large cement plant can make about 80% of the value produced compared to a Waste-to-Energy plant, but at only 40% of the capex. She suggested that the first 5% TSR is the hardest, since it involves overcoming barriers in the mind, not just of the plant’s neighbours, but also in the operating paradigm of the cement plant’s personnel and cement company management. The progressive technical steps towards great AF use are now well-trodden by plants around the world, including the use of a chlorine bypass, perhaps precalciner modifications, the use of AF conditioning capacity (and here Taís suggested the use of the Rocket Mill) and finally modifications in the main burner. The Rocket Mill consists of fast-rotating horizontal chains in a chamber surrounded by a sizing screen, providing high-surface-area AF, with size reduction in a single step and with a moisture reduction of around 10% at the same time.

Next was a co-authored presentation by Neville Roberts of N+P and by Iakovos Skourides of Vassiliko Cement, on the results of burning SubCoal in a large precalciner kiln. SubCoal is a patented waste-derived pelletised fuel, with high CV, low moisture and high bulk density. The fuel is odourless, dust-free and hydrophobic. Neville presented results showing that SubCoal can be co-milled with coal, even at high levels of substitution. N+P eventually partnered with Vassiliko Cement (part-owned by HeidelbergCement) on Cyprus to try a full-scale trial for SubCoal, on the two-string five-stage precalciner kiln, commissioned in 2011. The cement plant already uses high levels of AF, of up to 50%, including RDF/SRF, chopped tyres, sewage sludge and MBM, although AF use is maintained at a lower rate of around 30% to optimise clinker quality. Thermal oxidation of coal mill off-gases has been used at the plant to control odours, after complaints from neighbours. Iakovos pointed out that SubCoal is milled to fibres, rather than to particulate dust and due to its high volatile content its combustion temperature is substantially lower than coal. He detailed some of the challenges of milling SubCoal that were encountered in the two week trial, but also pointed out that all of the challenges were overcome. The variable speed on the main drive of the coal mill was used to increase the mill speed: this actually decreased the level of vibrations on the mill and allowed a higher grinding force to be applied. During the trials the mill capacity was decreased and the specific power was increased. Alite content of the clinker was not influenced and nor were free lime or kiln capacity affected. The trials achieved an additional TSR of 5% on top of previous AF substitution rates. Neville Roberts pointed out that SubCoal can be used with next-to-no capital expenditure, allowing a cement-producer to try out AF for the first time at low cost.

Next up was Thomas Jennewein of FLS Pfister, who spoke about a case study at National Cement in Dubai, which has a production capacity of 1.5Mt/year, using primarily oil and gas. Increases in fossil fuel prices led to the company’s exploration of the use of ‘alternative’ fuels - originally in 2011 pulverised coal dust, but from 2015 carbon dust (from aluminium production) and tobacco dust (from cigarette production). To be able to dose each of these materials, two of Pfister’s rotor weigh-feeders were installed at the plant, while a 102MW FLS Duoflex burner was also installed. The systems enabled the substitution of 3960t/yr of coal, allowing a return on investment of less than three years. In a second case study at Arabian Cement Company in Egypt, FLS Pfister installed a fully-automatic multi-fuel facility for storage, handling and dosing of AF (dried sewage sludge, MSW, rubber, packing waste etc) for direct firing of the calciner, at a capacity of 10t/hour and a TSR of 30%.

The final presentation of the day was given by Samuel Zühlsdorf of thyssenkrupp Industrial Solutions, on the Prepol Step Combustor. Samuel pointed out that the world population will increase to 8bn by 2025, with 60% urbanisation and 6Mt of waste produced each day. To help the world cope with this diverse waste stream, Polysius developed the Prepol Step Combustor, with a combustion residence time of beyond 1000 seconds. The Combustor is shaped like a descending set of stairs, with combustion air provided from a cooler off-take. Fuel is introduced to the combustion chamber by feeder screws. Combusting fuel is then pushed slowly down the stairs using air cannons. Coarse fuel particles remain on the steps, but fines are entrained into the tertiary airstream, so that only non-‘flyable’ particles remain on the grate. Preheated raw meal passes over the Combustor in the process gas to effect heat exchange. Samuel outline an installation at the Lägerdorf cement plant in Germany, which has been online for more than four years. He stated that the use of municipal wastes is quite challenging, but offers the greatest economic benefit. It is possible to increase or decrease the size and number of steps in the Combustor to customise the degree of combustion: when configured with the least number of steps, the Combustor becomes a fuel pre-preparation, drying and pyrolysis unit, with only around three minutes of residence time. A Prepol SC has been installed at the HeidelbergCement Schelklingen plant in Germany and two other contracts are also underway one in Central America and one in South America.

Global CemFuels Awards Dinner

The Global CemFuels Awards Dinner took place at the Classic Remise Berlin, a classic car centre, with ‘Berlin flavours’ in music, food and drink. The Global CemFuels Awards were presented at the event: CRH was award AF-user of the year and N+P was awarded supplier of the year. Molinari won for technical innovation of the year for its TP series of shredders, while Vassiliko Cement (and N+P) won for AF project of the year. Samuel Zühlsdorf of thyssenkrupp took the prize for project manager of the year and Cembureau was awarded the prize for outstanding contribution to the use of alternative fuels. Con Manias of FCT, Australia, was awarded the Global CemFuels ‘Personality of the year’ award. It was announced that the next Global CemFuels Conference will take place in Amsterdam in February 2019.

Second day

Pietro Cella Mazzariol of Entsorga started the second day of the conference, by suggesting that “the waste drives the technology.” Municipal solid waste varies from country to country and from region to region and the approach to processing it should vary as well. Pietro said Entsorga’s main business is to provide mechanical-biological-treatment (MBT) plants, incorporating a bio-drying stage to reduce moisture content of the organic fractions. His main question was whether SRF can be produced economically through MBT in areas where landfill fees are low or non-existent. He concluded that SRF can be produced at a cost of around Euro1/GJ. It is up to the fuel markets to decide if that cost is acceptable.

Eric Plantié of Precimeca next gave a case-study on tyre-derived fuel preparation, using his company’s tyre shredding equipment. The tyres are actually sheared and no debeading (metal removal) is required: output is generally of chips of 25mm size, with no protruding exposed wire and with uniform size. Eric pointed out that tyres are usually among the first AFs to be used, since scrap tyres are generally ubiquitous, have low seasonality of supply, high bulk density and are not prone to water uptake, so that they can be stored outside. Crucially they have a CV of close to that of coal or petcoke, at 25-30MJ/kg. On average, tyres have a high biomass content, at around 30% and also supply iron to the material mix in the pyroprocess. Eric introduced Konya Cement in Turkey, which in 2013 wanted to start using tyres as an alternative fuel, with a target TSR of 30%. Precimeca provided a pragmatic solution suited to local solutions, which worked well enough that the plant ordered a clone plant in 2017, both operating at 5t/hour of 40mm chips, using three shifts and manual tyre handling, year-round.

How to mitigate the impacts of AF on pyroprocessing was the subject of the next presentation, given by Stéphane Poellaer of Alterline, who first pointed out that you will create a huge mess if you try to use AF on a kiln that is not already operating in a stable state. AF use will involve a higher heat consumption, a higher exhaust gas volume, a higher input of chlorine and changes in kiln operation and kiln behaviour (particularly the ‘speed of response’ of the kiln). AF has a higher moisture content compared to traditional fuels, while solid or pasty AFs have a higher ash content. Solid AF has a coarser granulometry than other fuels, leading to poor combustion, while the feeding of AF can lead to extra false air from additional feeding points. The potential inhomogeneity of AF can lead to thermal input fluctuations as well as feeding challenges. The higher chlorine content of AF can also lead to coating formation and blockages in the pyroprocessing system. AF will also change the nature of the kiln flame, in terms of temperature, radiance, length and other parameters. The use of AF also critically affects kiln capacity through the volume of flue gas that is required, but this may only be significant if the kiln is already being used at maximum capacity, for example in a sold-out market. Increased corrosion and thermal shocks due to unstable coatings may also be a consequence of AF use. There will also be an effect on the emissions from the kiln, but these are not always negative: NOx will decrease due to a cooler flame temperature and SO2 may also be reduced. The effects of AF on clinker quality are very specific to the conditions of the plant and can be either positive or negative (or neutral). Stéphane pointed out that “the higher the process complexity, the more important is the regularity and stability of the whole clinker process.” Before stating with AF, you should make an estimate of the effects on the pyro-system. Consider the lessons from other plants, both successful and unsuccessful. Always inject at the calciner first, since impacts are lower. Use the various ‘tools’ that will help with AF use, but always start with a stable and optimised kiln system.

Basri Ogut of ATS Group - Walter Materials Handling next spoke on best practices for AF dosing and feeding installations using case studies from Sharjah Cement (UAE), Holcim Ecuador, Cimentas Izmir (Turkey) and the Martres-Tolosane plant of LafargeHolcim in France. The project at the Holcim Guayaquil plant in Ecuador in particular was unusual, in that the AF was dosed into ‘Doseahorse’ dosing unit at the top of the preheater and thence into a double valve airlock, using an orange-peel grab system that dug into a storage pit at ground level, the entire handling system being enclosed in a full-height purpose-built tower.

The first paper in the session on AF preparation was given by Katrin Salbrechter of the Montanuniversität Leoben, Austria, on the theory and practice of the drying effects of the new Rocket Mill. The AF being dried in the mill contains moisture in a number of forms, including capillary water, absorbed water, pore water and internal micropore water, the first two being rather easier to eliminate that the pore water and internal micropore water. In the Rocket Mill, 67% of the energy introduced into the system is used up in shredding, while 27% is used in heating up the material and associated process air: 5% is considered as ‘loses,’ possibly due to radiative heat loss from the equipment. Katrin stated that in her experiments, input moisture was 11% and output was 7%, a reduction of 37% and comparable to other stated results on the mill which suggested a reduction - processing higher moisture material - from 25% to around 15% (a reduction of 40%).

Luigi Di Matteo of the Di Matteo Group of Beckum, Germany, next suggested an holistic approach to AF use in the cement industry. Luigi said that AF must be characterised not only in chemical, physical and thermal terms, but also in safety hazards. He pointed out that a particle goes through a number of steps during ‘combustion,’ starting with drying, passing through pyrolysis and the release of volatiles, thence to ignition, coke burnout and finally leaving behind the residual ash component. Luigi said that AF must be stored carefully, in order not to over-consolidate the materials and to avoid handling problems. He pointed out that for each important step in AF utilisation, from reception, preparation, storage and transport, to dosing and feeding, Di Matteo offers a variety of equipment solutions, depending on scale, material types and client requirements and budgets.

Felix Bartknecht of SICK AG next spoke on sensor solutions for AF usage. He gave details of a particular case with a belt scale being used with AF, which was prone to a variety of maintenance and usage problems. SICK offered a laser scanner for non-contact volume flow measurement, which also provides information on bulk height and on the centre of gravity of the material on the conveyor belt. The scanner can also be used for crusher, raw materials, coal, AF, clinker and stockpile monitoring and measurement. Another plant used a LiDAR instrument with image analysis to detect deformed tyres which would tend to block the tyre handling system. Felix finally outlined the use of the SCP3000/MCS300P hot-wet gas sampling and analysis system, which keeps the process gas at above 200°C so that there is no condensation and no gas cooler is required and which can be used to measure circulating elements and to control combustion, thermal conditions and fuel consumption.

The penultimate paper at the conference was given by Frank Thomasberger of Schenck Process Europe GmbH, looking at Multiflex precision dosing for alternative fuels. The Multiflex is a screw weighfeeder, fixed on load cells, where the dosage is proportional to the speed of the screw. Frank pointed out some of the challenges of obtaining an accurate value for dosing from a screw weighfeeder, particularly when dosing problematic materials like AFs. For example, the filling level of the screw must be known (or it must always be full, for instance with the use of a wide inlet into the screw), the system must be calibrated and shunt forces must be handled or avoided. The system is also designed to cope with explosion risks. Frank suggested that the measurement value accuracy of the system is 99% of the actual feed rate.

The final presentation at the conference was given by Oscar España of Vidmar Group, on a special belt weigh-feeder for alternative fuels. Oscar firstly pointed out Vidmar’s capabilities for AF in reception, classifying, storage and dosing. Oscar suggested that it is more sensible to think about dosing rates in terms of energy/time rather than mass/time, due to the wide variability of the CV of AF. Flexibility of feeding and dosing is required especially when feeding different AFs with different CVs. He suggested that the most important thing about a dosing system is that it should never stop and should have 100% reliability: repeatability is crucial, but accuracy - he suggested - is of lower importance, since the other components in the pyro-system will be tuned to deal with whatever the dosage system actually doses. He outlined the newly-designed AWF adaptive weigh feeder with integral lump breaker and double weigh bridge.

Conference prizes and farewells

At the conference farewell reception a number of prizes were awarded. SICK was awarded the best exhibition stand prize. Stéphane Poellaer of Alterline was awarded third place for his paper on mitigating the negative process effects of AF, Matthias Mersmann of aixergee Process Optimisation was awarded second place for his paper on calciner modifications to maximise AF use. The winner of the prize for best presentation was Luigi Di Matteo of Di Matteo Group for his paper on an holistic approach to AF use.

The conference was highly commended for its organisation and for its technical content and delegates agreed to meet again at the 13th Global CemFuels Conference in February 2019, in Amsterdam.

13th Global CemFuels Conference 2019
20 - 21 February 2019

The 13th Global CemFuels Conference on alternative fuels for the cement and lime industry has successfully taken place in Amsterdam, with 185 registered delegates, 33 exhibitors and 22 presentations on the latest developments in markets and technologies for alternative fuels. The conference included two field trips, to the N+P SubCoal fuel preparation plant at Farmsum, and to HeidelbergCement's CBR cement plant in Lixhe, Belgium (group photo above). The 14th Global CemFuels Conference will take place in February 2020 in Cyprus, with a confirmed visit to Vassiliko Cement.

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View a short video about the Global CemFuels Conference 2019 - and a preview of CemFuels in Cyprus in 2020!

The first presentation at the Global CemFuels Conference 2019 in Amsterdam was given by Frank Brannvoll of Brannvoll APS. He forecast that carbon prices will increase significantly after 2020, once demand for permits increases past available and stockpiled permits. Coal is still very much in demand around the world, particularly in China and India, underpinning global energy prices. Oil prices are expected to be sustained in the US$60-80/barrel level and above.

Michael Hinkel of Geocycle gave the next presentation, on the regulatory framework for alternative fuels (AF). Michael said that following the merger of Lafarge and Holcim and the establishment of the GCCA (Global Cement and Concrete Association) there was a feeling that the guidelines for the coprocessing of alternative fuels in cement manufacturing needed to be updated. Target groups for the guidelines were relevant government authorities, the concerned public and their representatives, NGOs, financiers, waste generators, cement manufacturers, associations and equipment manufacturers. The new guidelines include an extended scope to encompass pre-processing and they emphasise the fact that co-processing is a key enabler of mineral recycling and energy recovery. The guidelines underline the fact that co-processing has a role in the circular economy, in resource efficiency, in mitigating climate change, reducing marine litter and in achieving sustainable development goals (SDGs). He suggested that companies engaged in co-processing should help to establish the regulations that control industrial activity, where the regulations do not exist or are out of date. The guidelines also point out that companies that are involved in co-processing should consult with and consider the interests of informal waste workers (since, for instance, Cairo’s Zabbaleen ‘garbage people’ recycle 85% of the city’s waste, providing thousands of livelihoods).

Alexander Larionov of the International Finance Corporation, part of the World Bank Group, next spoke of the importance of the cement sector in the company’s work. Thermal substitution rates (TSR) in Africa range from zero in some countries, through around a 5% average for the continent, to 15 - 20% for standalone projects in Kenya, Nigeria and Senegal. Very strong potential for AF growth exists in Egypt, with around 2Mt/year being divertable from landfills, with a likely 3 - 5 year payback and 15% internal rate of return (IRR) for good AF projects.

Amie Stringer of Totus Environmental next spoke on ‘alternatives to solid recovered fuels, SRF.’ Essentially Amie suggested the increased use of blended fuels, offering improved chemistry and homogeneity, although possibly requiring some alterations to pyroprocessing set points.

Andy Hill of Cynosure Partners pointed out that refuse-derived fuel, RDF, has an upper calorific value (CV) limit of around 15MJ/kg, beyond which point the fuel should be considered as SRF. Higher-value SRF exports from the UK are increasing, while lower-value RDF exports have reduced. Andy suggested that SRF will become increasingly commoditised. There has been an increase in thermal value of AF, due to the ban on plastic waste imports into China. Other heavy industrial sectors are increasingly using AF, leading to price pressures on supply. Andy concluded that there is still plenty of opportunity in developing markets to increase the use of AF.

Mark Terrell of Andusia explained how waste markets are evolving in Europe. Mark mentioned that the UK Landfill Tax is now at GBP£91/t, one of the highest rates in the world. He suggested that it is becoming easier to produce a more standardised SRF, with calorific value of higher than 18MJ/kg, size smaller than 20mm and chlorine content of less than 0.8%. A new product is coming onto the market that is effectively a heat-treated SRF that looks like coal and behaves in a similar manner, with CV of around 28MJ/kg, but at a higher cost than SRF.

Stéphane Poellaer next gave a run-down of the most cost-effective measures that can be used to mitigate the negative effects on pyroprocessing of the use of AF. “The limiting factors depend on the kiln type and must be determined for each kiln type. Do not attempt to use AF if the kiln is not fully under control!” stated Stéphane. The main challenges are a higher exhaust gas volume, a higher input of chlorine and changes in kiln behaviour. Typically, cement kilns are limited by the ID kiln fan capacity and use of AF can therefore bring additional challenges. Stéphane suggested that any new AF user should consider feeding material to the calciner first of all, since lower combustion temperatures are required, and the calciner is less sensitive to temperature fluctuations. “Fight against false air!” exhorted Stéphane.

Luigi Di Matteo of Di Matteo Group gave some ideas on best practice on the use of AF. For pre-preparation of fuels, as well as for all aspects of storage, handling, feeding and dosing of co-processing, Di Matteo can provide highly capable pieces of equipment and indeed whole systems for AF use. Di Matteo 4.0 is a new approach to linking all pieces of equipment to ensure that they work much better together.

Moritz Siegfried of SICK AG next spoke on sensor strategies to promote the maximised use of AF. Process gases can be analysed using the SCP3000 gas extraction probe, or using the MCS300P hot wet gas analyser system to keep process gases above the dew point. High levels of circulating alkalis from AF combustion can be detected before they create blockage problems.

Johannes Bartusch of Claudius Peters Projects GmbH next gave some details of a low-pulsation conveyance approach for efficient burner feeding with AF. Instead of using a single large pipe, a number of smaller pipes are used to promote the spontaneous development of higher-efficiency dunes in the conveying lines. Delegates were intrigued and were keen to hear about future research developments.

Matthias Schumacher of Aixergee next gave details of a case study at the Dyckerhoff Lengerich plant in Germany. The calciner at the plant was designed for firing lignite, with a short retention time of 2 - 3 seconds. Elevated CO emissions were encountered when using fluffy calciner RDF and with pelletised RDF: coal-free operation was not possible. The plant wanted to increase the TSR to 100%, at low CO emissions. Unsurprisingly, pelletised AF requires a higher gas velocity for suspension, compared to fluffy fuels. This meant that fluffy fuels were easily suspended and passed through the calciner very quickly. Pelletised particles tended to circulate in the calciner, giving time for a complete burnout, but producing higher CO due to a lack of oxygen as a result of low levels of gas mixing. The engineers at Lengerich suggested the installation of a swirl-inducing pre-combustion chamber at the bottom of the calciner, leading to longer residence times and lower CO production and increased ability to burn cost-efficient fluffy fuels.

Gala dinner and Global CemFuels Awards

The conference dinner took place at the Heineken Brouwerijen in Amsterdam, with the presentation of the Global CemFuels Awards. The outstanding project award went to Lafarge Kujawy, for a project with Lindner Recyclingtech. Alternative fuel user of the year was HeidelbergCement, while supplier of the year was N+P. Innovative technology of the year was the kiln inlet gas analyser system from SICK, George Americanos of Vassiliko Cement was named project manager of the year for a second time, and a joint World Bank/Government of Vietnam effort to use hazardous wastes as AF was named as the outstanding contribution to the promotion of the use of alternative fuels. Andy Hill of Cynosure Partners was named as the Global CemFuels ‘Personality of the Year.’

Second day

On the second day of the conference, Juan José Riesgo of FLSmidth gave details of smart AF solutions for a fast return on investment, giving examples from Cementos Molins, near Barcelona. After an initial AF project in 2011 and a later update in 2014, important lessons were learned. These included that great care must be taken to exclude foreign bodies from the AF; to reduce moisture levels to as low as possible to avoid blockages; that there should be wear-protected bends and large diameter (500 - 700mm) pipes; that fermentation and auto-combustion must be mitigated; and that the system should be built to be able to cope with as many different fuels as possible. Juan detailed a new AF ‘starter kit,’ incorporating an infeed hopper or docking station, rotor-weighfeeder dosing and pneumatic transport, Jetflex Plus burner and ‘very fast’ payback.

Marcus Brew of Untha Shredding Technology next spoke about alternatives to fast-running post-shredders for the production of AF. He suggested that an ideal solution would be a medium-speed machine with a flat-blade cutting system, greater resistance to unshreddable items and faster recovery from any incidents, and with the possibility of the machine being semi-mobile. Marcus gave details of such a machine, at Lancashire Waste Recycling. Using a variety of input materials, LWR produces <30mm SRF main burner fuel and <80mm SRF calciner fuel using a selection of Untha equipment, including an XR XC medium-speed mobile shredder.

Francisco Leme, consultant, next introduced the first of three papers on AF use in South America and in Brazil in particular. Brazil has a cement production capacity of around 100Mt/year, but a TSR of only around 15%: there is an intent to raise the level to that of Portugal (35%), which is likely to involve the use of an additional 2Mt/year of municipal solid waste (MSW). Francisco pointed out that Argentina and Paraguay also have great potential for AF use, although the cost of transport, lack of waste policies and absence of waste treatment facilities are ongoing problems. Tyres, MSW and biomass are the predominant AF types. Average TSR for South America for 2030 is forecast at 22%, but this will require a huge amount of investment and widespread policy support for the use of AF. Critically, these markets are not sold-out, so that there is a strong economic driver for the use of AF.

Delivering a paper co-authored with Daniel Lemarchand, Francisco Leme next presented a ‘road map’ for the Brazilian cement industry for the promotion of the use of AF. Cement industry CO₂ emissions only represent about 2% of Brazil’s total, since land use changes, deforestation, and agriculture (primarily cattle ranching) are much larger sectors than in other countries. Francisco suggested that a combination of reducing clinker factor, electrical energy efficiency, AF use and CCS/CCU will reduce the CO₂ emissions of cement from 564kg CO₂/t of cement in 2014, down to 375kg CO₂/t of cement in 2050. Brazil is estimated to produce 300Mt of agricultural biomass each year, of which 170Mt is sugarcane bagasse and straw. To achieve a ‘European’ level of 55% TSR by 2050, huge changes in technical adoption, legislation and habits will have to occur.

The final of the three presentations on South America was given by Sandro Conceição of Cimpor/InterCement, looking at the societal impact of coprocessing. InterCement worked with farming associations and cooperatives in Brazil in order to develop supply sources of quality biomass, while at the same time improving rural incomes and to increase farming sustainability. Sandro reported that the projects were successful on many levels.

The session on AF case studies was started by Neville Roberts, on behalf of N+P Alternative Fuels Ltd, who spoke on the latest developments in the company’s SubCoal product. N+P supplies 1.5Mt/ of alternative fuels, primarily in Europe, primarily in the cement industry, but is also looking outside of Europe and at other industries (steel, electricity, waste to chemicals, lime) as well. SubCoal is a patented technology for the production of pelleted high grade SRF. New developments mean that the pellets will be more easily milled to finer particle sizes. A number of new SubCoal production plants are under development around Europe, including one at Teesside in the UK. The pellets have CV of >20MJ/kg and ash content of less than 12%, even with biomass content of >50%. Neville reiterated that what is important in an alternative fuel is the amount of chlorine per unit of energy, not necessarily the total amount of chlorine.

Con Manias of FCT next spoke about optimised air-entrainment to allow the use of lower quality alternative fuels. Con spoke about the detailed design of burner face plates and how this affects the flame and its radiation profile, as well as the production of NOx and other emissions. Alternative fuels need an optimised burning environment and it has been found that firing with high velocity air and grouped apertures at the burner tip, in an ‘AF boost’ mode, improves air entrainment and heat transfer to the kiln meal, albeit with an increased NOx production of 20 - 25%.

Next Mohammed Hamada Ali Ahmed of El Nahda Cement of Egypt spoke about the use of dried sugar beet pulp as an alternative fuel for the cement industry. The AF has CV of 3.5MJ/kg, ash content of 3% and moisture content of 12%. Around 100,000t/year of the material is available in the environs of the El Nahda cement plant in Upper Egypt, in pelletised form, and which is currently used as animal feed. The cost on the markets is around US$50 - 80/t which is less expensive than the cost of petcoke at the plant.

Jan Tuma of Beumer Group, Czech Republic, next gave a case study of AF systems for RDF at the Dyckerhoff Deuna Zement plant in Germany. The RDF has particle size of less than 60mm, with density 0.08 - 0.3kg/m² and moisture of around 15%. The overall system has a capacity of 30t/hour, or 375m²/hour.

Ville Hakanperä of BMH and co-author Mr Meng from Handan BBMG (Beijing Building Materials Group) Taihang Cement Ltd next spoke about a zero-waste AF production plant project in China. The cement plant produces 3.5Mt/year and to keep its license to operate it was obliged to take a certain amount of MSW: nothing was allowed to go to landfill, hence the required ‘zero-waste’ concept for the AF production plant. Input into the plant is in the form of MSW and also from mining of the adjacent landfill. Due to the particular nature of Chinese MSW, fully one third of the input feed of the plant is an inert fraction (for example from mixed construction and demolition waste, in the form of bricks and stones) and this material is used as raw material for the cement plant, which is located 20km away from the waste plant. During the initial negotiations, the need for fine screening was ruled out by the Chinese side, but now a fine screening step is being considered to further refine the process. The plant could process more waste if it could be obtained.

Leos Volesky of Schenck Process and Martin Kubant of Cemex Prachovice gave the final presentation, on the importance of accurate alternative fuel dosing. The plant uses many different fuel streams, including RDF and animal meal. The MultiFlex compact closed-unit weighfeeder or MultiDos belt weigh feeder can be used for feeding alternative fuels. Leos concluded the conference by reiterating that “Accurate dosing is required for optimised kiln stability.”

Farewells and prizes

At the conference farewell reception a number of prizes were awarded. Francisco Leme’s paper on AF in Brazil was awarded fourth place in the best presentation awards, while Stéphane Poellaer was in third place. Matthias Schumacher of Aixergee was the runner-up with his paper on the development of a new swirl chamber at the Dyckerhoff Lengerich plant. Con Manias was awarded the prize for the best presentation for his paper on the design of a burner optimised for alternative fuels.

To a strongly positive response, it was announced that the 14th Global CemFuels Conference on alternative fuels for cement and lime will take place in February 2020 in Cyprus, with a confirmed visit to the 6000t/day Vassiliko Cement plant. See you there!

Selected videos from the Global Cement Fuels Conference 2019