| 摘要 |
PROBLEM TO BE SOLVED: To eliminate restrictions from a viewpoint of material and at the same time, facilitate maintenance services by bringing a recovered hydrochloric acid solution into gas/liquid contact with air in a liquid cooling column to cool the hydrochloric acid solution and returning the air used for cooling and discharged to a gas cooling column together with an original hydrogen chloride gas, to perform the hydrochloric acid recovery operation. SOLUTION: A discharge 71 of hydrochloric acid is introduced into a hydrochloric acid solution cooling column 30 and is made to flow down to a bottom part liquid reservior 30a passing through a filled layer 30b. Next, the discharge 71 is mixed with a hydrochloric acid solution stored previously and the mixture is circulated with the help of a circulation pump 50. On the other hand, the air to be sent by a blower 10 through a suction tube 19 is made to circulate from the lower part to the upper part of the hydrochloric acid solution cooling column 30, and the temperatures of the discharge 71 and the circulating liquid are lowered through the gas/liquid contact. After that, the heated-up air is introduced into the top 31c of a cooling column 31 from the column top part 30c to be mixed with a high temperature gas 21 originating from a surnace 1. Thus the air is likewise treated as the high-temperature gas 21 to recover hydrogen chloride to avoid the diffusion of the hydrogen chloride following the release of cooling, air into the atmosphere.
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