5th Global Cement Refractories and Maintenance Conference & Exhibition
12 - 13 May 2015, Istanbul
Image gallery for the 5th Global Cement Refractories and Maintenance Conference & Exhibition
The 5th Global Cement Refractories and Maintenance Conference and Exhibition has successfully taken place in Istanbul, Turkey, with around 100 delegates from 16 countries in attendance. The event was supported by the TÇMB and the AUCBM, and also featured a popular field trip to the Akçansa Büyükçekmece cement plant.
The 5th Global Cement Refractories and Maintenance Conference, after two events in London, one in Düsseldorf and one in Ankara, took place in Istanbul, the global crossroads and meeting place.
Hakan Gürdal, president of Sabançi Holding cement business group, and chairman of the board of Akçansa, Çimsa and Afyon Cement, started the conference by saying that Turkey is the biggest cement producer in Europe, with high current capacity utilisation rates. At the end of 2014, Turkey’s total cement production capacity was around 77Mt, with total consumption of around 65Mt, the difference mainly being exported. Since Turkey, and Istanbul in particular, is a major earthquake zone, the government has undertaken a huge programme to demolish unsafe buildings and to rebuild them in a safer manner. [In fact, the famous restaurant where the conference dinner took place, Beyti in Istanbul, was constructed of artfully-camouflaged massive reinforced concrete beams and would literally have withstood an earthquake.] However, continued Hakan, after 2015 the gap between Turkish cement supply and demand will increase, due to over-building of capacity and a moderation of demand. The Turkish cement industry is strongly dominated by Turkish players, with Vicat, Cementir and Votorantim being the only ‘foreign players’ with cement plants, and HeidelbergCement and Titan present in joint ventures. Alternative fuel (AF) usage rates are relatively low and growing only slowing, partly due to bureaucracy in waste collection and permitting. Hakan Gürdal stated that Turkish cement plants are among the most cost-efficient in the world, and the resultant profitability has led to new players entering the market with new capacity. Turkey exports to MENA, west Africa, the CIS and other regions. In 2013 exports topped 12.4Mt but dipped to 10.7Mt in 2014. Hakan stated that many input costs for the cement industry are low at the moment, including petcoke and electricity, but that despite this the selling price of cement at around US$50/t is still too low, due to fierce competition between producers.
Hakan’s company Çimsa, produces grey, white and calcium aluminate cement, with a total of 5.5Mt/year of capacity and sales to more than 60 countries. Calcium aluminate cement production started in 2002 and the company has an annual production capacity of 45,000t/year. The cement has high resistance to sulphate attack, excellent heat resistance up to 1200°C, high and fast early strength and applications as a grout, mortar, self-leveling underlayment and many other uses. The material can also be used as a refractory, and for precast applications. Hakan concluded with some general comments: A new general election will come in June 2015, but despite this the cement industry faces a tough future. Capacity utilisation rates are expected to decrease to around 60%, with some kilns likely to be closed and some not being restarted after maintenance. The price of cement may sink to below $40/t, partly because clinker stocks currently amount to more than 7Mt. Cost pressure on maintenance and refractories will inevitably increase, while electricity, fuel and refractory costs will all increasingly be under the spotlight. Additional capacity due to be added to the Turkish cement industry is forecast to amount to 5.5Mt in 2015, 7Mt in 2016 and the same again in 2017 - over 19Mt of additional capacity in only three years. Syria and Iraq may be increasingly important export markets in the future, depending on the political situation. Carbon restrictions may also become more important in the future, creating a further hurdle for exports to Europe. Hakan forecast tough times ahead for all cement producers on the Turkish market, with the potential purchase price of Turkish cement capacity falling to lower than the cost of building the capacity [in which situation mergers and acquisitions by cash- or credit-rich outside players become more likely]. “Life will not be easy for any of us,” he concluded.
Robert McCaffrey gave the next presentation, on the nine mega-trends that will shape the future of the global cement industry, being the aging of societies; the maturation of the global economy; a post-boom phase in China, the rise of alternative mega-economies, increased environmental costs; increased fuel and energy costs, the decline of clinker and rise of supplementary cementitious materials or SCMs; ever-increasing competition and Rumsfeldian ‘unknown unknowns.’
Peter Koeck from Magnesita next spoke about future refractory challenges. The company is the third largest refractory supplier in the world, behind RHI and Vesuvius, with 29 production locations. The company has over 1Bt of proven reserves of the world’s highest quality magnesite and dolomite, with around 200 years of reserves left at current usage rates. Over 80% of the company’s raw materials comes from its own mines. Future challenges are weak cement prices, challenging raw materials including impurities and additives, production costs (particularly where there must be a high availability of equipment that is being driven above its design parameters in a sold-out market) and energy costs. Thermal, chemical and mechanical loads on refractories will all increase in the future. Peter spoke about basic brick options from Magnesita, where a double-burning process achieves a larger crystal size with a lower boundary area of crystals, offering a smaller area for chemical attack. In the Magkor A1 brick, the expansion mismatch between fused spinel and magnesite reduces the modulus of elasticity of the brick, thus improving the thermal shock resistance of the brick by keeping it flexible. High density bricks offer lower porosity and high resistance to liquid phase infiltration. In the Magkor AZT brick, the combination of pure raw materials and the special zircon-bearing matrix bond improves the hot modulus of rupture at 1500°C to an extended level and provides very good elasticity which will not be reduced by alkali salt infiltration, while also creating high resistance against mechanical abrasion. ‘Low Permeability Technology,’ means that bricks have very low permeability and a very dense microstructure, decreasing the rate of impregnation, improving service life and protecting the kiln shell. The coating behaviour of the brick is vital, to protect the surface of the brick from abrasion and also to reduce alkali and sulphur infiltration, and Peter suggested that the Sindoform range of bricks is suitable for the burning zone, being stable to 1800°C and having a melting point above 2100°C.
The next presentation was given by Professor Ismail Duman of Istanbul Technical University, speaking about 10,000 years of the use of stone by mankind. Flint and obsidian were first to be used, but later cooked clays were found to harden and could be used in a variety of applications, including being shaped into the form of the archaic callipygous Venuses still found in archaeological digs in Turkey and elsewhere. The professor showed a peace treaty from 1300BC between the Egyptians and Hittites, written in cuneiform script on a clay tablet. Passing through the innovations of Joseph Aspdin and Louis Vicat, we have arrived at modern cements, including refractory monolithic materials. The professor stated that monolithic refractories used in the cement industry actually reach their final strength once they have been heated to around 1250°C, and if the concrete is exposed to wear before monolithic refractories have achieved this temperature and full strength development, then they may suffer higher wear rates and degradation. Gunning, ramming, casting and trowelling may all be used for monolithic refractory placement. The treatment of refractory anchors is crucial to long refractory service life: the choice of anchor material, shape, numbers and size will have a significant impact on refractory lifespan. The professor warned against over-insulation, which may lead to high concentration of alkalis along the refractory/insulation boundary, leading to refractory anchor attack and eventual refractory failure.
A paper by MVW Lechtenberg pointed out the importance of the Alkali Silica Ratio in the raw meal (and fuel inputs) with different suites of sulphur, chlorine and alkali salts likely to condense in the pyroprocessing system as a result. Alternative fuels tend to increase the chlorine content of the system (and sulphur content, to a lesser extent), leading to the familiar blockages, build-ups and ring formation often see with alternative fuels, and also leading to increased corrosion of refractories. Low permeability bricks should be favoured, while the elimination of chromium-containing bricks (which are prone to mineralisation, phase changes, swelling and failure) can also be a solution of refractory problems with alternative fuels.
Vasilicos Kechagias of SuperAlloys Engineering next gave a bonus presentation on in-situ hard-facing and machining in the cement industry. Vasilicos spoke about a number of examples where in-situ grinding/cutting/plasma gouging and/or hardfacing (depending on whether the equipment needed to be taken down to a surface or built-up). The equipment and parts of equipment that can be treated include roller bearing housings, grinding tables, kiln tyres and shafts.
Next Dr Tarek Nasr asked, “Does it make sense to extend the design lifetime of deteriorating concrete-based structures, such as preheater towers, in cement plants?” In general reinforced concrete (RC) constructions are designed for a 50-year lifetime. However, cement plants suffer under heavy duty operation and may show heavy damage. Typically there may be a long passive preliminary phase in the RC, before cracking occurs, chemical attack proceeds, spalling accelerates and collapse becomes inevitable, with changes happening more rapidly in the latter stages. Early repair is much cheaper than later action. Common issues that may lead to concrete damage may include problems with drainage from roofs, columns being impacted (by vehicles for example), unexpected dust accumulation, high groundwater levels and humidity behind technical installations such as cabling or instrument cabinets. In practice it is important to have a thorough investigation of the situation in each individual cement plant, including the taking of samples of concrete to determine the level of degradation, for example through alkali-silica reaction. Tarek gave an example of the strengthening of a preheater tower in Europe, where the top level of the tower was demolished since it was not being used, cross-bracing was installed and the post-tensioning of beams was undertaken, leading to a reduction in deformation and wind loading. He concluded that to achieve best results, the owner, the designer and the contractor must work together as a team.
Frank Henning of FLSmidth Oelde GmbH gave the final presentation of the day, showing a veritable ‘chamber of horrors,’ of examples of kiln shell deformation, cracking in the kiln shell where clinker falls through, twisted shell where the refractory fails and the shell become too hot and plastic, brick failures with white-hot hotspots, kiln tyres that are cracked, pitted and deformed, bearings that are unlubricated and are not doing their job, lubricants that do not lubricate because they are dirty or contaminated, gears that are so noisy that the neighbours complain, cracking in ball mill shells, cracked pinions, breakouts from tooth flanks and many other examples of insufficient maintenance. Frank suggested that a repair and refurbishment programme can avoid many, if not all, of the worst cases in his chamber of horrors, potentially through a service agreement. The paper was very well-received by the audience.
On the second day of the conference, Matt Savage of ITS Engineered Polymers spoke first, on composite wear protection solutions. Matt spoke about belt repair, stating that the surface preparation - including a thorough degreasing stage - is the most critical step: He suggested that Devcon R-Flex a self-leveling modified urethane can be applied to belts that are worn or that have tears or rips. Moving into the hotter zones of the cement plant, Matt pointed out that duct walls might traditionally have been lined with ceramic tiles, but that these can easily crack due to thermal shock or impact. He suggested the use of the Densit Wearflex range of cementitious coatings, which can be applied to a welded steel mesh and which include a wear-resistant aggregate which is exposed after slight wear of the installed surface and which then leads to extended wear-resistance. The Densulate system consists of a Densit wear lining installed on a mesh fixed on Densit Super Isol and can be used to insulate ducts and pipes with relatively low weight compared to normal refractory. Ceramic-filled epoxies can be used for pipe lining, allowing fast cure and excellent metal adhesion. Matt finished by describing a solution that can be applied to the outside of a pipe that is failing, almost like a sticking plaster, that will allow a few weeks of use out of a failing pipe.
Mehmet Safaltin of Schaeffler Rulmanlari spoke about the great variety of different bearings that may be used in the cement industry. For example, chromium-coated bearings might be used for vibrating screens, whereas spherical, cylindrical, tapered or axial bearings might be used in other applications. Bearings must be specified to be shock-resistant if required and must be adequately lubricated for long service life. Special case hardened bearings may also be required for long service life and machine availability. Mehmet pointed out that after lubrication failures, incorrect mounting of the bearings is the most common cause for bearing failure. Condition monitoring can also be used to extend bearing life. “Counterfeit products endanger machines and lives,” concluded Mehmet.
Okay Kilinç of Akçansa wrapped up the conference presentation programme by introducing the Akçansa Büyükçekmece plant that delegates were shortly to tour as part of the conference programme. Akçansa has three integrated plants in Turkey, with a total clinker production capacity of 6.5Mt/year and a grinding capacity of 9.4Mt/year. The company has a separate grinding plant, two ports (with a large capacity port at Çanakkale), four aggregate plants and 38 RMC units. The Büyükçekmece plant has a health and safety centre, where subcontractors may be trained. Okay Kilinç stated that the predominant cement type produced at the factory is Cem I 42.5 or 52.5, with low alkaline cement, sulphate-resistant cement and low-heat and sulphate-resistant composite cements also being produced. The plant’s limestone quarry is 17km away from the plant, and trucks are used to transport the rocks to the cement plant. A Hazemag impact crusher of 600t/h capacity is used to crush the limestone at the cement plant. The Büyükçekmece plant has four raw mills, with two VRM mills from Gebr. Pfeiffer in use, and one ball mill from FLSmidth still in use. The plant has three rotary kiln lines, two provided by KHD and the latest provided by FLSmidth, with a total capacity of 6100t/day of clinker. The plant uses 100% ‘domestic’ Turkish refractories. The plant has 90,000t of clinker storage capacity, and can sell around 8000t/day of cement. The plant has a substantial packing capacity, using Ventomatic, Caricamat and Haver & Boecker machines, but Okay stated that packed cement is currently “out of fashion,” with only 15% being bagged. The plant has a port with extensive loading and unloading capabilities using BMH Marine equipment. Three health and safety specialists and a H&S manager are employed at the plant in order to accomplish the company’s ambitious safety targets.
The plant is permitted to use waste plastics, used tyres, waste oil, sewage sludge, ‘contaminated waste,’ and ‘bleaching earth.’ However, the plant is not burning tyres at the moment, since tyres are not available on the market at a reasonable price, since Turkish tyre manufacturers ask for a fee of Euro35/t for used tyres: other plants have now taken to importing tyre-derived fuels. The waste plastic facility was provided by Vecoplan, and has a capacity of around 4.5t/hour. Dried sewage sludge can be used at a rate of 4t/hour and Okay reiterated the point that quality control must be strictly controlled, in terms of calorific content and moisture content. The plant is surrounded by residential areas, and a number of ‘green’ projects are ongoing. A previously-open coal storage area has been enclosed in a ‘stadium-like’ stockyard and a raw material area will be enclosed later in 2015. ID fan replacements by Venti Oelde have meant a reduction of at least 2kWh/t of clinker for each fan. Dynamic separator installation has been accomplished by Magotteaux, reducing specific energy consumption in the mill and retaining customer satisfaction with the end product. Boldrocchi installed new bag filters in 2013 which have led to much lower emissions. All three burners have been modified to allow increased use of alternative fuels. A new SNCR project has been instituted on all kilns, in preparation for more stringent emissions standards that are expected in the next few years in Turkey. Okay Kilinç proudly said that the plant’s cement is being used in the new Bosphorus bridge, which has concrete piers 330m high.
During luncheon the conference presentation prizes were awarded, based on delegate votes: Matt Savage of the ITW Wear and Abrasion Group was third, Peter Koeck of Magnesita was second, but Okay Kilinç of Akçansa was a popular winner of the best presentation award. Delegates then had a chance to experience warm Turkish hospitality during the visit to the very interesting Akçansa Büyükçekmece plant, before the final end of the conference programme.
The conference received high marks on the conference questionnaire, particularly for the very good networking opportunities. As one delegate wrote, “Thank you for this wonderful event and for the opportunity to be part of it - I was delighted to participate and I look forward to meeting you again soon.”
