Objectif To save energy by recovering the heat contained in the acidic fumes at temperatures below their dew-point and emanating from the drying operation of a bleaching powder plant. The air heated by the recovered heat will be fed back into the drying oven, saving an estimated 327 TOE/yr of primary energy. The novelty in this process consists in the use of ''Teflon'' as a corrosion-resistant coated on the heat exchanger. A 3 years payback is to be expected at project level.During the preliminary start-up, several deficiencies were found in connection to the PFTE lining of the heat exchanger, the optimum function of the mist eliminator and the increased discharges of drips from the chimney due to condensate formation in the chimney waste-gas-stack. To avoid these defects, several actions were taken including repairs, coupling of dust eliminator and modification leading a partial quantity of the produced warm air into the waste-gas-stack. These modifications caused a 29% cost increased and a 25% decrease in actual energy economy measured. The equipment reliability is still to be proved during the measurement campaign.In the Moosburg plant, bleaching powder is produced by treating aluminium ore with hot HCl (hydrochloric acid). The hydrochloric residues are then air-dried in ovens, from which air exists at a rate of 200,000 m3/hr and at a temperature of 110 deg. C, close to the dew-point. Part of this chlorine-containing(60,000 m3/hr or 48,000 kg/hr with 21% of steam) is fed into a heat-exchanger built of glass-tubes in stainless steel casings (tubes and plates), coated internally with PTFE (Teflon). The airtightness between the tubes and plates will be provided by metallic gaskets coated with PFA, a highly thermal and chemical resistant material. The two airflows will move in counter-current, with the air to be preheated flowing inside the tubes. The primary air, cooled to 70 deg. C, will flow to a humidifier for washing and then be released in the atmosphere. For a 38,000 kg/hr flow of air preheated from 20 deg. C to 76 deg. C during an annual 6,500 hours operation, a saving of 13 970GJ/year of natural gas can be achieved. From this, the electricity to operate two additional fans i.e. 130,000 Kwh/year must be substracted, leaving a net saving of 13 500 GJ/year, equivalent to 327 TOE/year.The heat recovery will be measured in 12 monthly recordings of temperature and flow. The pressures, dew-points and water consumptions will be equally monitored by the 30st June 1987. 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 SUED-CHEMIE AG Contribution de l’UE Aucune donnée Adresse LENBACHPLATZ 6 POSTFACH 202240 8000 Munich Allemagne Voir sur la carte Coût total Aucune donnée
