Objectif During their search for possiabilities of reducing the energy required for cement milling, the people at Dyckerhoff AG learned about the positive experiences of Messrs. Kloeckner Humboldt Deutz with the high pressure comminution of clinker on a laboratory scale. The only thing amiss was the possibility to test this revolutionary development in the comminution of cement raw materials and clinker on a large scale.The question if a high pressure roller press can be profitably used in the comminution of cement clinker, can be answered by "yes".This study has mainly shown that an effective employment of the high pressure depends on the connected milling system. With continuous flow milling units capacity increase as well as energy savings were considerable.With air separator mills the advantages of pre-pressing in the high pressure roller press can only be established when high-efficiency air separators are available.One big advantage of the high pressure roller presses supplied by Kleckner Humboldt is their compact construction which makes it possible to install them without in already existing milling units. Most probably this will be the area in which the high pressure roller press will mainly be used in the future.The high pressure roller press installed at the Lengerich plant of Messrs. Dyckerhoff AG was the first machine to prove its capacity under the conditions of industrial operation. In the meantime another approx. 50 machines produced by the two largest manufacturers of high pressure roller presses, Kloeckner Humbolt Deutz (KHD) and Krupp Polysius, have been sold worldwide.It can be assumed that Dyckerhoff has taken a forerunner position in operating the HW-RP 115-100 at Lengerich; this is also illustrated by the fact that more than 100 visitors have travelled to Lengerich from all parts of the world to observe the high pressure roller press in operation.In addition to the novelty of feed bed comminution the name "Dyckerhoff" might also have been a decisive factor for this high degree of interest.The comminution of the raw materials for the production of cement - like that of other brittle materials - involves high energy expenditure. Due to the fact that they represent a large proportion of the total energy expenditure, the costs for grinding influence the production costs of cement decisively.One promising new method is the two-step comminution. The feed material does not receive impact to the individual particles but is drawn between two couterrrotating rollers, being fed as bulk or particle bed. The particles are then pressed intensely enough to produce fissures and fractures within the grains. The pressure of more than 50 MPa, i.e. more than 500 bar, compresses the pressed ,material to form socalled scabs which can be broken up at low energy expenditure in an additional desagglomerator.The scabs already contain up to 30 % of finished product as well as precomminuted material which is comminuted further down to the fineness of finished product in an additional aggregate. This post-comminution, however, requires considerably less energy as microfissures in the grains improve the grindability.Comparing the sale expectations at the time of application with the actual situation, it is realized that the percentage of the higher-quality cement PZ 55 has increased more and that the sale of deep well hole cement has decreased during the last year.The average consumption of milling energy consequently increases from approx. 40 kWh/t to 46.6 kWh/t. The expected energy savings of 27.5 % could not be obtained, but only savings of electrical energy of 8.5 %.On the basis of the 1986 numbers (energy savings : 1.5 mio kWh/a) the following statement energes from the calculation of the profit : Investment costs for the planning, approval acquisition, installation, assembly, putting into operation and optimization of the high pressure roller press : 3.5 mio DM Savings of electrical energy : 1.5 mio kWh/a at an estimated energy price of : 0.15 DM/kWh Costs of high pressure roller press with 8 years of operation : 437,500 DM/a Energy savings : 225.000 DM/a Programme(s) ENG-ENALT 2C - Programme (EEC) of demonstration projects relating to the exploitation of alternative energy sources and to energy saving and the substitution of hydrocarbons, 1983-1985 Thème(s) 3.2 - INDUSTRY Appel à propositions Data not available Régime de financement DEM - Demonstration contracts Coordinateur DYCKERHOFF AKTIENGESELLSCHAFT WERK LENGERICH Contribution de l’UE Aucune donnée Adresse 4540 LENGERICH Allemagne Voir sur la carte Coût total Aucune donnée
