摘要 |
A process and system are disclosed for the bridging of operational standstills of an ammonia washer of a plant operating according to the semi-direct technique for the removal of ammonia from coking oven gas. During the operational standstills of the ammonia washer, the ammonia is washed out from the coking oven gas in a secondary cooler constituting three parts, an upper part (Wash Stage I) provided with stripped water from an ammonia still, a middle part (wash stage II) provided with gas water, and a lower part (wash stage III) provided with circulation water. All of the waters provided for the secondary cooler are collected in its sump, and after a separation of the circulation water necessary for the Wash Stage III, it is split into two partial streams, one serving for the recovery of stripped water for Wash Stage I and which is led into an ammonia still provided only with water vapor and the other partial stream is led into an ammonia still provided with water vapor and alkali. Also disclosed is a system containing a secondary cooler defining three vertically disposed sections of metal mesh beds.
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