| 摘要 |
<p>1447519 Gas separation SIMON-CARVES Ltd 21 Dec 1973 [30 Dec 1972] 59587/73 Heading C1A [Also in Division C5] Ammonia, hydrogen sulphide and hydrocyanic acid are removed from gas such as coking gas by scrubbing with an aqueous solution of metal salts of sulphurous acid and sulphuric acid, and the resultant substance is circulated through an oxidizer and a partial stream of the thus treated liquid is drawn off and with the addition of a heating medium is subjected to combustion, the products of combustion, which contain nitrogen, steam, formed oxides of sulphur and metal oxide, being cooled, oxides of sulphur and metal oxide being thus combined to regenerate a fresh solution, the solution being used for maintaining the scrubbing liquid in the circuit. Nickel which has a catalytic effect may be added to the aqueous metal salt solution in such a quantity that the nickel content is at least 2À1%, preferably 4% to 10% of the entire metal content of the solution. The partial stream which is to be combusted is prepared in such a way that the particle size of the metal oxide resulting during combustion is between 5 Á and 200 Á, preferably between 5 Á and 20 Á. The combustion products pass through a heat recovery unit before condensation and the metal oxide dusts may be separated from the gas phase before condensation. Condensation may take place in a two-stage tower whereby dust-free combustion waste gases are led into the bottom stage and metal oxide dusts are led into the top stage of the tower. Any excess oxides of sulphur resulting from oxidation of the hydrogen sulphide may be intercepted at the head of the condensation tower by washing with an alkaline solution, e.g. ammoniacal water or milk of lime.</p> |
