| abstract |
A process for purifying flue gas which still contains, in addition to nitrogen oxide, at least one further noxious gas, in particular sulphur dioxide and/or hydrogen chloride. It is known to remove the nitrogen oxide from the flue gas by contact with a sodium chlorite-containing scrubbing liquid in a first stage and then to carry out a desulphurisation in a second stage. In this case, in the first stage, owing to reaction of the sodium chlorite with sulphur dioxide, an excessive sodium chlorite consumption occurs. Moreover, a sodium chlorite-containing waste water arises. The denitration stage is provided downstream of the desulphurisation stage and, possibly, further scrubbing stages. The suspension arising in the denitration stage is added to the scrubbing liquid of the desulphurisation stage. As a result, the sodium chlorite consumption is decreased, the separation efficiency for sulphur dioxide is improved and any loading of the waste water with sodium chlorite is avoided. Flue gas purification in refuse incineration plants and coal- or oil-fired power stations. <IMAGE> |