METHOD AND DEVICE FOR REMOVING DUST AND GASEOUS POLLUTANTS FROM EXHAUST GAS, ESPECIALLY EXHAUST GASES IN THE LIGHTWAVE LEAD PREFORMING

摘要

A method is disclosed for purifying waste gases containing extremely finely dispersed pollutants in dust form and pollutants in gas and vapor form, particularly for purifying waste gases produced in chemical vapor phase reactions during the manufacture of optical waveguide preforms. In a first step, dust is extracted in a dry, coated fabric filter (1). The gaseous and vaporous pollutants are then absorbed in a gas scrubber. During this gas-scrubbing process, as soon as the absorption liquid circulating in an absorption-liquid circulation system reaches a pretermined pollutant concentration, part of the absorption liquid is withdrawn from the absorption-liquid circulation system and detoxicated in a separate detoxication circulation system. The part withdrawn is simultaneously replaced by fresh, unpolluted absorption liquid. The method requires little maintenance, is fully automatic and, since the necessary chemicals are added in measured quantities, keeps chemical consumption to a minimum while fully satisfying the legal requirements for prevention of air and water pollution.