| 摘要 |
<p>The invention relates to a process for the purification of industrial waste gases containing SO2 together with other harmful gas constituents, such as hydrogen fluoride, hydrochloric acid, SO3 and nitric oxides (NOx) by treating the flow of raw gas with ammonium ion containing solutions and ammonia. According to the invention, the flow of raw gas is treated in a reaction tank in a number of successive stages, a solution which contains ammonium ions is introduced into the first stage, the gas dew-point being raised by partial evaporation of such solution. The gas is cooled below its dew-point in the second stage, ammonia is introduced into the resulting gas mist mixture in the third stage, and the resulting ammonium salts are precipitated in the bottom part of the reaction tank in a fourth stage by treatment with an ammonium ion-containing solution. The salts are fed to a reservoir, while the purified waste gas passes through a cooler before being discharged to the chimney, the waste gas being cooled in the cooler with the preferably cooled solution containing the precipitated ammonium salts. This process is less polluting than those presently known.</p> |
