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Gerold Keune, commercial director, started the Pfeiffer Convention 2014 with a short overview of the company's 150 years of history. Jacob Pfeiffer (senior) was the founder and earliest driver of the still 100% family-owned company, which received a huge boost based on the commercial application of a patent for innovative wind separators from Englishman Robert Moodie. Jacob senior's two sons Karl and Jacob founded the Gebr. Pfeiffer ('Pfeiffer Brothers') company which started out as a strong producer of steam engines, but which soon led on to hard comminution using ball mills and also as a producer of large rotary kilns. However, the company has since specialised in grinding using vertical roller mills. The company's focus has shifted from France, Russia, the UK and Japan to Asia, Africa and the Americas. In a reflection of this fact, the convention welcomed 200 guests from 35 countries, with notably large delegations from Turkey, India, Iran and Vietnam. The company supplies the MPS roller mill for clinker and the most often used coal grinding and gypsum grinding/calcining equipment worldwide. The MVR Mill, launched in 2010, is now the largest-capacity installed mill type in Asia, North America, South America, Africa and Australasia. Delegates at the convention were all presented with a copy of the interesting book 'Progress is our tradition,' charting the company's triumphs and tribulations, including its near-destruction during the Second World War and it's subsequent successes and innovations.
Robert Schnatz, technical director, then pointed out that after the boom years ending in 2008 when around 600 mills were sold, around 300 mills are now sold each year in the global cement industry, with around 100 being vertical roller mills. Fully 97% of coal mills are VRMs partly due to their high turn-down factor, while over 90% of slag mills are VRMs. However, only 40% of cement mills are VRMs, with ball mills and high pressure grinding rolls still taking up a significant market share. VRMs dominate for raw materials, slag and coal, and the market share for cement is increasing. Mills with more than 6000kW are becoming more common, while split grinding plants are becoming popular - where a grinding plant is built away from a integrated plant and closer to a customer. Robert Schnatz also announced that Gebr. Pfeiffer will start to take on EPC contracts: "We are happy to serve you," he concluded.
Bernd Henrich next spoke about the operation of the MVR cement mill without external heat, using the Balaji 5600 C-4 mill in India as an example. He pointed out that the useful portion of the energy input into a vertical roller mill is in the comminution effect, which transfers energy from the motor and gearbox into the grinding table and rollers in order to reduce particle size by crushing, transforming energy into heat. After optimising the amount of water spray used to stabilise the grinding bed at Balaji, it was shown that the energy from the hot (115°C) clinker and energy from grinding was sufficient to allow optimised operation of the mill. Even using cold clinker, for example at a grinding station, it is still possible to optimise mill optimisation without an external heat source. On the other hand, the higher the availability of an external heat source, the more options are available for grinding, for example including the use of wet materials such as wet fly ash or high-humidity FGD.
Dr Caroline Woywadt next spoke on the operating data from the largest VRM in Australia, at a 1.1Mt/yr sea terminal grinding station Port Kembla. Large modules were shipped from Spain from contractor Cemengal with a very high degree of pre-assembly to minimise site works, while the facility was designed to be fully automated, to maximise operational time and to minimise labour costs. A Pfeiffer MVR (Modular Vertical Roller) mill with MultiDrive was selected for the project, to reduce mill down-time and to reduce mill spare parts stock. The mill table diameter was 6m and had a cast weight of 76t. The efficiency of grinding in the VRM means that there is a relatively low heat in the mill, leading to a lower level of gypsum dehydration, and this can lead to a low level of gypsum reactivity. In this case, more gypsum can be added, or a more reactive form of gypsum, or more heat can be added to the system, resulting in increased dehydration and higher reactivity of gypsum. Separate gypsum calcining for cement grinding leads to a significant overall reduction of thermal energy consumption, a reduction of the volume flow for the plant fan compared to the 'single process' and the possibility of optimising the cement properties with an adjustable degree of gypsum dehydration and therefore setting time. The conference was to return to the topic of gypsum later in the programme.
Mr H.M. Bangur of Shree Cement spoke about MVR mills at the RAS, Bihar and Raipur plants of Shree Cement in India. Having bought 24 Gebr. Pfeiffer mills (so far), Shree Cement is a confirmed convert to the company's products.
Jens Reimers then returned to a topic from earlier in the day and gave details on Gebr. Pfeiffer's plans to become a major player in the EPC - Engineering, Procurement and Construction - business for turnkey grinding plants and terminals, adding the construction capability to its offering. The company's EPC business will be applicable to greenfield or brownfield projects, can be undertaken as a single contract partner or as part of a consortium, can be clinker or coal, and can be undertaken on a range of terms from 'at cost plus fee' to 'turnkey lump sum.' The move means a significant increase in the project management capabilities and capacity of the company. GPSE will partner with SNEF/Cemprocim and with Triplan AG/Cresta of Austria to provide EPC contracts.
After the first day of the convention, delegates were entertained at an exquisite gala dinner at the spectacular local town hall.
Second day
Returning to the Gartenschau Convention centre for the second day of the event, delegates first heard Dr Joe Harder of OneStone Consulting speak about new trends in the cement industry. Dr Harder pointed out that global cement demand has been driven by Chinese growth for perhaps the last two decades, but that this is a trend that is about to end. Per capita cement consumption in China is set to peak as urbanisation reaches a plateau, and will subsequently decline: China now has significant excess cement production capacity - and excess cement equipment production capacity. At the same time, Chinese producers have steadily taken five places in the top 10 largest cement producers in the world and so far have demonstrated higher growth rates than their western counterparts. Dr Harder suggested that the addition of new clinker capacity in the rest of the world has slowed as well, from around 140Mt in 2010 to 50Mt in 2013. Middle-ranked multinationals such as Votorantim, Eurocement, PPC, Dangote and Argos are growing rapidly, partly since their markets and production capacity are almost entirely in fast-growing developing nations. The LafargeHolcim merger will produce a combined company with 427Mt of cement capacity, but around 50Mt of capacity will be divested, almost all in developed markets, with the money reinvested in developing markets where the return on investment will be much higher. Joe finished with a discussion on the clinker factor, which is relentlessly reducing around the world. In China the clinker factor is at around 0.70, and in the rest of the world it stands at around 0.78. This means that global cement production capacity is still growing faster than the global clinker capacity.
Sascha Hamm of Gebr. Pfeiffer next spoke about Pfeiffer mills in Turkey, using the Limak Group as an example. Limak Cemento has already ordered nine vertical roller mills for raw material, coal and clinker grinding from Gebr. Pfeiffer, progressively replacing its ball mills in its Turkish plants in order to reduce its specific energy requirements and costs.
Patrick Heyd then spoke about solid fuel grinding with the Pfeiffer MPS mill. More than 2000 units have been sold, not just to the cement industry but also to power plants. The closed-housing design allows air-tightness and avoidance of air/oxygen leakage and reduction of explosion hazards. At the same time, the mill housing is explosion-proof up to 8 bars, and has no horizontal surfaces for coal dust to settle upon. Among other examples, Patrick showed a lignite grinding mill for PT Cemindo Gemilang in Indonesia that can produce 100t/hr with a feed moisture of 37%, using a 4.5m diameter grinding table, by far the largest vertical mill for grinding solid fuel in the world.
Eckhard Sander next spoke about the use of MPS grinding technology for the grinding-calcination of gypsum. Pfeiffer has two systems for producing beta-plaster: direct calcining with the MPS mill and indirect calcining in the GK gypsum kettle. In the MPS mill, the gypsum is ground and flash-calcined in one step, with a lower exhaust gas temperature than from the gypsum kettle. The flash calcination leads to 'popped' crystals, which are perfect for the production of wallboard, while the slower calcining kettles produce a higher quality plaster with better shaped crystals and a longer setting time. However, the MPS mill can be 'tuned' to alter the properties of the calcined gypsum product. A hot gas generator is required for the MPS mill, with the ingress gas at a temperature of 600°C: particular design modifications are required in the mill for it to cope with the high temperatures. Pfeiffer has supplied the world's largest mill for grinding and calcining of gypsum, with a table diameter of 2.8m for a production rate of nearly 95t/hr. FGD gypsum can be ground at up to a rate of only 50% of the feed rate due to grain size effects.
The final presentation at the convention was given by Axel Auerback, who spoke on the after-sales service of Gebr. Pfeiffer. In the future, Pfeiffer will divide the service contract into two parts: one part mechanical and one part process-related, both however starting with a thorough 'walk-through' inspection of the mill and its operation. Once the mill is fully understood, mechanical and process optimisation can proceed.
Patrick Heyd closed this enjoyable conference with warm words and wished all delegates a safe journey home.