TREATMENT OF GASEOUS CHLORINE DIOXIDE

摘要

PURPOSE:To perform treatment with the lower-limit reductant by sampling a part of circulation liquid for neutralizing and treating the exhaust gas of chloride dioxide and adding indicator liquid thereto and controlling the loadings of the reductant in accordance with its coloring change. CONSTITUTION:The exhaust gas of chlorine dioxide generated in bleaching work of a fibrous product is neutralized and treated by circulation liquid incorporating a reductant. This circulation liquid is taken out as the sampling liquid of two series with a pump. An upper limit indicator is added to one sampling liquid and a lower limit indicator is added to the other sampling liquid. The degree of discoloration for both indicators is sensed by a light transmission sensor 9 and the quantity of the reductant added to the circulation liquid is controlled by a controlling circuit 5 in accordance with the degree of discoloration thereof. Therefore the proper loadings of the reductant to be added to the circulation liquid can be always obtained.