| 摘要 |
<p>Coke-oven gas containing ammonia is passed is sequence through a condenser, where an aqueous solution of ammonia is obtained, a mixer, where the gas is contacted by sulphuric acid vapour to neutralize ammonia remaining in the gas, and finally through a tower for scrubbing with the ammonia solution.ALSO:Ammonia is recovered from gases by scrubbing with sulphuric acid, and the ammonium sulphate formed is decomposed by (i) heating the ammonium sulphate with ammonium bisulphate yielding ammonia and ammonium bisulphate, (ii) heating the ammonium bisulphate in a melt with an alkali metal sulphate (preferably a mixture of sodium and potassium sulphates) in admixture with the sulphate of another metal, preferably cobalt sulphate, yielding ammonia and metal bisulphate and/or pyrosulphate, (iii) heating the bisulphate and/or pyrosulphate to yield metal sulphate and sulphur oxides, the molten salts produced being returned to the preceding stage. Stage (i) is preferably conducted at 300-320 DEG C. and so as to liberate not more than 50% of the ammonia contained in the sulphate, the bisulphate formed being circulated to stage (ii), which is preferably conducted at 390-420 DEG C. Stage (iii) is preferably conducted at above 700 DEG C.</p> |
