APPARATUS FOR PURIFYING GAS

摘要

PROBLEM TO BE SOLVED: To reduce the amt. of an absorbent used by providing a two-stage structure to an absorption part in an apparatus for purifying exhaust gas in an automobile tunnel and introducing an absorbing soln. having deteriorated absorbing performance in the post-stage absorption part into the fore-stage absorption part. SOLUTION: Exhaust gas 1 contg. dust and NOx is introduced into a gas inlet 3 by a blower 2 and the NOx in the gas is oxidized to NO2 by a method such as the addition of ozone by an NOx oxidizing means 5. The NO2 -contg. gas and the dust are sent to a fore-stage absorption part 29 through a dust removing means 6 and the absorption of excess ozone and the preabsorption of the NO2 are carried out. The absorption of the remaining NO2 in the gas is then carried out in the post-stage absorption part 7. An absorbing soln. having deteriorated absorbing performance in the post-stage absorption part 7 is introduced into the fore-stage absorption part 29, the excess ozone is absorbed in the soln. and a fresh absorbing soln. is supplied to the post-stage absorption part 7. The leak of ozone into the post-stage absorption part 7 is suppressed.