Schweighofer D.,Erection Dep |
Luderich S.,Technical Services Dep |
Adams C.,POLYSIUS AG
ZKG International | Year: 2011
By example it is shown how the plant manufacturer can help to minimize the plant stoppage period required for component change-outs and the performance of repairs, thanks to his know-how as the supplier of machines and systems for kiln and grinding plants. The example concerns the refurbishment of a kiln plant equipped with a satellite cooler within the agreed time period, within the specified budget, to a high quality and - of great importance -without any accidents.The service package included the flat-rate installation of plant components, surveying of the rotary kiln and a mobile machining service for key components that could be reused. The refurbishment was performed on the basis of a detailed appraisal of the plant that was carried out on site before the order was awarded.
Simon C.,Zementwerk Cimalux |
Linnhoff U.,Polysius AG
Cement International | Year: 2010
In 2007 the Cimalux cement plant in Rumelange, Luxemburg, belonging to Buzzi Unicem decided to modernize the automated laboratory. For about the last 35 years the cement plant has produced between 830000 and 1000000 t/a clinker. This is transported by rail to the Esch grinding plant where it is processed into cement. The quality control is carried out by automatic sampling of the raw meal, of the kiln meal before it is fed to the kiln and of the clinker before it is filled into the silo, and by subsequent sample preparation and chemical analysis in the central laboratory. The decision to modernize the automated laboratory was made because of the excessive amount of maintenance required by the existing plant, because spare parts could no longer be obtained for the XRF equipment and also because of the high cost of the fused sample preparation system used in the laboratory. There were two possible solutions: the central automated laboratory with links to the existing tube conveyor system or installation of several new local online systems. The decision was made in 2007 in favour of the integrated POLAB®ACT automated laboratory from Polysius (integrated automated laboratory with tube conveyor reception system, metering system, POLAB®APMplus preparation module, manual sample input, sample retention magazine, transport belts to the available analysers, display and control of the system by PC with web-based POLAB® AQCnet software). One part of the task was to integrate the plant's existing sampling systems and to supply new sample dispatch stations that had to be connected to the existing tube conveyor network. The Axios Cement and CubiX PRO units offered by PANalytical were chosen for the analyzers. This article describes the reasons for the decision, the structure of the system and its implementation, and also contains a summarized assessment for an operating period of about 15 months.
Vibrations-aided gravitational flow of ultrafine cohesive limestone powder - Measurements and modeling [Schwingungsunterstützer schwerkraftfluss eines ultrafeinen kohäsiven kalksteinmehls - Versuche und modellierung]
Kache G.,Polysius AG |
Tomas J.,Otto Von Guericke University of Magdeburg
Chemie-Ingenieur-Technik | Year: 2012
Reliable storage, handling and dosing are essential at processing and manufacturing of ultrafine powders. The powder flow in a silo can be hindered by bridging or channeling. The excitation of mechanical oscillations by vibrating hopper has been proved to solve this flow problem. The minimum outlet width and wall friction are clearly reduced by this excitation of oscillations during the shear test. Next, these lab-scale design data are proven at pilot-scale silos. The influence of frequency and amplitude of oscillations on powder flow was investigated. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Tomas J.,Otto Von Guericke University of Magdeburg |
Kache G.,Polysius AG
International Journal of Chemical Reactor Engineering | Year: 2012
Typical flow problems, like arching or bridging, of ultrafine cohesive powders are caused by undesired particle adhesion, poor flowability and large compressibility and intensified by poor permeability. Thus, the physical understanding of micromechanics of ultrafine particle flow and permeation is very essential to design properly the product quality and to improve the process performance in particle technology. A force balance at a homogenously assumed, dynamic bridge is formulated at the hopper outlet that includes the dead weight, inertia, wall and drag forces. The permeation resistance is calculated as sum of a microscopic flow-around resistance of single particles plus the macroscopic bed resistance of the moving cohesive powder bridge. The resulting differential equation is shown for turbulent flow-through conditions of air. The first integration gives analytical discharge velocity-time function, steady-state discharge velocity and the characteristic discharge time of incipient (accelerated) flow. The second integration results in analytical heighttime and velocity-height functions, discharge and residence times. This method results in physically consistent, analytical models that are comfortable to handle and easy to prove. The steady-state discharge velocity is compared with measurements of full-scale silos at Coperion and Zeppelin companies. This publication describes the results of a closed collaboration between university and industry. The practical objective of the project was to solve the serious discharge problems of ultrafine, compressible, hardly permeable, cohesive powders by applying mechanical vibrations during their gravitational flow. Copyright © 2012 De Gruyter. All rights reserved.
Diedenhofen S.,Polysius AG |
Claussnitzer C.,Polysius Corporation |
Longhurst D.,Polysius Corporation |
Klotz B.,Texas Industries
Cement International | Year: 2010
Over the last 15 years high pressure roller mills have become increasingly important for producing raw meal. One example of this is the use of a high pressure roller mill at the TXI Riverside Cement Company in Oro Grande, California, USA. In 2005 Polysius was awarded a contract there to supply a mill of this type for drying and grinding the cement raw materials for a new dry-process kiln line with a planned clinker output of 6600 short t/d. The high pressure roller mill with 2.05 m diameter × 1.50 m rollers and an installed rating of 2 × 1700 kW is used for comminuting limestone with a moisture content of 1.0 to 1.5 % (maximum 3.0 %). 6.3 to 12.8% of the quartz particles in the raw mix are larger than 90 μm. The mill operates in conjunction with a static drying and disagglomerating grate supplied with hot gas, followed by a dynamic separator that is fed with material both pneumatically and by a elevator. The grinding plant has an average raw meal output of 510 t/h with a fineness corresponding to 80 % passing a 75 μm sieve. The measured specific power consumption of the grinding plant lies between 7.8 and 8.1 kWh/short t. The two grinding rollers were made of bainite and after 60 running hours their working surfaces were provided with autogenous wear protection by profiled hardfacing. Another improvement in this grinding technology was achieved in a grinding plant commissioned in 2006 at Vasavadatta Cement in Sedam, India, where a high pressure roller mill was being used for a raw meal output of 275 t/h at a guaranteed fineness corresponding to 20 % residue on 90 μm. This plant combines the use of the static drying and disagglomerating stage with a top-mounted separator with horizontal classifying cage rotor. The specific power consumption is more than 35 % lower than that of a vertical roller mill installed in the same plant for grinding raw meal. To extend the use of this modern grinding technology to include the processing of cement raw materials with higher initial moisture levels of up to 8 % Polysius has developed an alternative plantsystem where the static stage of the seperator is connected in series with an air-swept separator.
Baier H.,Polysius AG
ZKG International | Year: 2010
The increasing requirement to use alternative fuels means that rotary cement kilns are being converted to the use of calcineis and multi-fuel burners. However, the production of alternative fuels and the process technology must be matched even better to one another if the application rates are to be increased further without affecting the product or the emissions. This includes the fact that the alternative fuels must be characterized and appropriately processed not only chemically in accordance with the requirements of pollution control but also in accordance with the objectives of the thermal utilization process.This article describes the preliminary work and tests involved with the air-whirl-mill. Initial investigations into various pulverized alternative fuels have shown speeds of ignition and conversion that have previously been found only with pulverized coal and lignite.
Schulz D.,Polysius AG |
Menzel K.,Polysius AG |
Baier H.,Polysius AG
ThyssenKrupp techforum | Year: 2011
During the manufacturing process of cement approximately one third of the CO 2 emissions can be attributed to fuel consumed to decarbonize raw materials and generate the high sintering temperatures of over 1,400 °C. In order to decrease these emissions and costs significantly, increasing use is to be made of 'Alternative Fuels and Raw Materials' (AFR). For this purpose, Polysius has developed and implemented a tailor-made strategy showing high growth potential and significantly extending the value chain.
Lampe K.,Polysius AG |
Grund G.,Polysius AG |
Erpelding R.,Polysius AG |
Denker J.,Polysius AG
Proceedings - European Metallurgical Conference, EMC 2011 | Year: 2011
Rising energy costs and regulations on the efficient utilisation of resources including energy resources force plant operators in the metals sector as in all other industrial sectors to focus on these aspects. Both in power generation as well as in thermal processes, the use of renewable sources is becoming more and more important. In this respect, especially the utilisation of biomass plays an ever-increasing role. However, the fact that currently available biomasses feature very different properties with regard to particle shape and size, moisture content, calorific value and energy density in most cases renders their direct use impossible. The production of biocoal offers a solution to overcome these challenges and to provide homogenised, biogenic fuels. The main objectives to be achieved in biocoal production are efficient energy densification, bulk density maximisation and grindability optimisation for improvement of the material handling properties. Here, the torrefaction of biomasses, that is the thermal treatment of biogenic materials under low-oxygen conditions at temperatures between 250 °C and 300 °C, presents a suitable and energyefficient solution for biocoal production. Common methods for biomass torrefaction are, amongst others, thermal treatment in fluidised beds, in indirectly heated screw conveyors and in multiple hearth furnaces. With regard to uniform temperature distribution, efficiency and thus the final product quality, the multiple hearth furnace method is the preferred process of Polysius AG. A two-stage multiple hearth furnace (POLTORR) permits both drying and torrefaction of biomasses with feed moisture contents of up to 50 %. The main advantage of the two-stage process is the direct utilisation of the volatile components released during torrefaction for the drying process by means of post-combustion, so that under favourable conditions, an almost autothermic process control can be realized.
Baier H.,Polysius AG |
Menzel K.,Polysius AG
IEEE Cement Industry Technical Conference (Paper) | Year: 2011
Resources are becoming scarcer and more expensive worldwide driving a search for viable alternatives including the use of Alternative Fuels and Raw Materials (AFR). The cement industry began to use Residue Derived Fuels (RDF) after the oil crisis in the early 1980s. By 2010, their use had increased to about 10% replacement of the total thermal energy demand. Utilizing mainly used oil and tyres, RDF consists of different types of hazardous and non-hazardous waste from both industrial and municipal origin. © 2011 IEEE.