Objectif The aim of the project is the dehydration of oil-in-water emulsion residues with solar energy. Total solar surface 130 m2.Max. dehydration 60 - 65% oil which can be burnt, avoiding pollution problems.Right from the first test runs in Summer 1982 it appeared that fundamental modifications had to be brought to the plant. The following problems had to be solved:- Malfunctioning of the pumps caused by particles in the cutting oil emulsion. To prevent the recurrence of this problem an entry tank was added.- Control of the operation by density sensors impossible since the oil content of the emulsion fluctuated more than expected. The process was modified so as to permit the use of simple level gauges instead of density sensors.- Water evaporation insufficient. At the outset it was planned to pump the oil emulsion in the cycle through the cooling tower and the heat exchanger until an oil concentration of at least 65% is reached. The test runs showed however that the higher the concentration of the oil, the higher the energy needs for evaporating the water. As a result the required concentration could be achieved only at a low pace. Modifications were necessary in order for the evaporation in the cooling tower to be completed through the floating effect at the surface of the storage tank.After those modifications were made operation resumed.Between Sept. 83 and August 1984 the plant processed 62.8t of waste cutting oil emulsion, and not the anticipated capacity of 100t. from the emulsion 4t oil were gained and 58.8t water were evaporated. the system efficiency, expressed as the ratio between the energy needed to evaporate the water and that irradiated on the solar collectors, reached a peak of 37.1% (August 1983). the minimum value of 6.3% was reached in December 1983.In order to increase the plant's productivity, i.e. to make it work even in the absence of sunlight (day and night), the addition of a natural gas-fired boiler was deemed necessary. It was estimated that a capacity of 58 kW would be required. With this boiler it has been estimated that over 10 years savings of 108 mlit will be made.From copper rolling mills and machinery oil-water emulsion polluting residues occur, +- 400 m3/year. The innovative aspect of this project is to dehydrate these emulsions by heating with solar energy through a cooling tower. The 130 m2 flat plate collectors are linked to a heat exchanger. This heats the emulsions before passing in the cooling tower. The emulsions are recirculated several times from a tank through the evaporation column. The emulsion is concentrated to 60 - 65% oil with a considerable volume reduction. Mixed with other oil it can be burned in a furnace.The solar plant is situated some hundred meters from the copper rolling mills and the machinery plants. The collectors are of flat plate type with copper absorbers. They are inclined at 45 deg. C facing south. The collectors are built by the contractor, type SMI-SOL-CSSI.No major problems were met when mounting the installation. During the 1982 testing and operating a few changes had to be done:- Clogging problems in the emulsion pump appeared due to small pieces of metal. The rotors of the pumps had to be replaced by less fragile ones.- Insufficient reliability of the control system from the storage tanks to the processing tanks, which was solved. The Summer of 1983 further experience was gained which led to some more changes in the process: - Use of two tanks - one exclusively for the sedimentation of the incoming emulsion, the other one for the dehydration process.- The collection tank works in a closed loop until the minimal level is reached, then the dehydrated emulsion is returned into tank 2.The concentrated oil is pumped off near the surface of tank 2 into a separate storage tank (9 m3).The contractor plans to install a special boiler to use the concentrated oil for his own heat demand. Programme(s) ENG-ENALT 1C - Programme (EEC) of financial support for projects to exploit alternative energy sources, 1979-1984 Thème(s) 3.1 - THERMAL Appel à propositions Data not available Régime de financement DEM - Demonstration contracts Coordinateur La Metalli Industriale Contribution de l’UE Aucune donnée Adresse Borgo Pinti 99 50121 Firenze Italie Voir sur la carte Coût total Aucune donnée
