High efficiency dynamic separator
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TSV : The high-efficiency dynamic classifier and its latest developments FCB-CRCM Ph.Duhamel, A.Cordonnier and D.Lemaire FCB-Research Centre Cement and Mineral Industries CRCM > The use of classifiers on a powdery product with a given grain size allows the product to be divided into two parts: the first one made up of fine particles and the second one of coarser particles. However, depending on the quality of the classifier cut, the segregation of fine and coarse particles is more or less precise. One of the traditional classifier applications is found in grinding plants for which the ground product feeds the classifier which sends the coarse part to the grinding mill inlet. This enables regularity of the finished product to be obtained in accordance with specific criteria for fineness. The performance of a grinding plant depends of course on the grinding mill used with however a significant part depending on the classifiers capabilities. The principle of separation lies in the use of centrifugal force generated by way of a flow with vortex (cyclone and derivatives, etc.) for static classifiers or a rotating turbine for dynamic classifiers. The evolution in the technology of classifiers can be summarized briefly. The first classifiers of the ғstatic type separate the coarse particles from the fine particles by a cyclone effect although limited with regard to the admissible material load for inlet as well as separation efficiency. The next generation, called first generation dynamic classifiers, has a rotating plate to disperse particles with a small axial selection turbine. Air circulation is ensured by a centrifugal rotor which is placed in the upper part. The fine product is recovered by decantation in a double conic casing. By adding an external air circuit to suck in the gas output with the fine particles instead of the integrated rotor, we have come to second generation dynamic classifiers which are traditionally installed with peripheral cyclones. The third generation includes a radial turbine which ensures radial separation and no longer axial separation. Figure 1 : Static classifier Figure 2 : First generation > SRBII - fragmentation commitee Study day ԓDry screening and classification-28/3/1996 page 1 >

TSV : The high-efficiency dynamic classifier and its latest developments FCB-CRCM Figure 3 : Second generation Figure 4 :Third generation The TSVή developed in 1990 by FCB, the technology of which will be explained in Part 2, is an advanced third generation classifier. The evolution of classifiers has followed a policy of improvement of their cutting ability, characterized by a better sorting of fine and coarse particles and a weaker by-pass. Furthermore, in Part 3, we will present the industrial results of the TSVs set up in different grinding plants (traditional or ventilated ball mills,...

TSV : The high-efficiency dynamic classifier and its latest developments FCB-CRCM air-swept TSVή: top feeding TSV: The matter is placed in suspension in the fluid flow and it all feeds TSVή from the bottom. This type of feed allows less space to be taken up and use in vertical grinding mills or air-swept ball mills. The matter arrives in bulk from the top of the classifier onto the roof of the turbine which disperses the material between the stator and rotor blades. As for the clean gas, feeds the TSV from the bottom. This configuration allows for a higher matter throughput. > REJECT Figure...

TSV : The high-efficiency dynamic classifier and its latest developments FCB-CRCM The flow of gas is rectified by way of the adjustable stator blades, which allows the tangential speed of the gas to be adapted to the turbine rotation speed so as to obtain only a radial speed of the fluid of the turbine. Therefore, a drag speed which is directly centripetal and opposing the centrifugal force is obtained which limits wear of the blades by the absence of particle impact on the latter. A closing which is adapted to the blades causes pressure loss which is favourable to the proper homogeneity of...

TSV : The high-efficiency dynamic classifier and its latest developments FCB-CRCM (1-Stg)/2 (St+Stg)/2 FirstGeneration First Efficiency Second Generation Second Third Third Generation St Efficiency % 00.10.2 0.30.40.50.60.7 0.80.91 110100 s Stg Mesh Mesh m Size M = ln(10)=2.3tg՟= Ms Mc Pt.M/4 t g s= Pts .M/4 SRBII - fragmentation commitee Study day ߓDry screening and classification-28/3/1996 page

TSV : The high-efficiency dynamic classifier and its latest developments FCB-CRCM The sizes which allow the slope of the sharing curve to be assessed are defined in reduced coordinates: - Imperfection I > =΢Ȓ ddd7525250. - Acuity > = > dd2575 - The slope of the straight line obtained through linearisation of the cutting area of the sharing curve in reduced coordinates expressed in a diagram semi-Log : > = Atan(-0.5/log(Acuity)) The evolution of the classifiers has followed a rationale of decreasing imperfection, global by-pass and the presence of outsized coarse particles in the finished...

TSV : The high-efficiency dynamic classifier and its latest developments FCB-CRCM Feed t/h 220 140 Throughput gas m > 3 /h 69000 69000 Material load kg/m > 3 3.2 2.0 Recycled LoadL 7.1 4.6 R8m % 70.4 70 Dcut յm 33 33 Reduced imperfection 0.26 0.26 Global by-pass % 16 2 Pressure loss daPa 160 110 Turbine power kW 14 9 > The following table provides the average values of specific energy depending on the type of grinding plant. > Material Coal Raw materials from cement works Cement (~3000 Blaine and dcut=35 m Cement (~4000 Blaine and dcut=22 յm) ) Turbine kWh/t 0.15 0.15 0.25 1.1 Ventilation...

TSV : The high-efficiency dynamic classifier and its latest developments FCB-CRCM It has been observed that in plants equipped with the TSVή, the output obtained is practically always very close to 1 or even considerably higher than 1 for criteria in R90 or R100 thanks to the very small amount of imperfections obtained. For cement grinding plants, the average values correspond to a great number of industrial reports, part of which have already been published [1]. These ranges are quite large and vary from one designer to another. The following table indicates the substitution rates for...