| 摘要 |
<p>PURPOSE:To excellent control the requisite amt. of ammonia by supplying the gaseous ammonia necessary for a denitration device from a stripping tower for evaporating the ammonia in aq. ammonia by the ascending steam. CONSTITUTION:Aq. ammonia is passed through a preheater 9 from an ammonia tank 6, heated therein, and introduced into the stripping tower 10. The stripping tower 10 is a counter-current gas-liq. contact tower wherein a liq. flows downward from the upper part and a gas flows upward from the lower part. Live steam is then blown in from a steam pipe 11 at the lower part of the stripping tower 10. Consequently, the aq. ammonia is heated, the dissolved ammonia is evaporated, and a mixture of gaseous ammonia and steam is generated from a gas pipe 13. The mixture is heated by a superheater 14, and introduced into the denitration device. At this time, the condensed water of the injected steam and the water remaining after the evaporation of the ammonia in the aq. ammonia are discharged from a drain pipe 15. When the ammonia concn. in the waste water decreases to about 0.1%, almost the whole amt. of the ammonia contained in the introduced 25% aq. ammonia is evaporated.</p> |
