| 摘要 |
1425818 Removal of sulphur oxides AMERICAN AIR FILTER CO Inc 21 Jan 1974 [7 March 1973] 2769/74 Heading C1A A process for treating stack gases containing sulphur dioxide comprises contacting the stack gas in a contact zone 15 of a gas scrubbing tower 11 with an aqueous medium containing a sulphur dioxide reactant material, e.g. calcium and sodium carbonate or bicarbonate, trona, natrolite or calcium hydroxide or combinations thereof, to form an initial reaction product and thence passing the aqueous medium containing this product from the scrubbing tower 11 to the upstream end of a filled continuously flowing reaction tank 19 where the initial reaction product is driven, by further reaction, to a more stable second reaction product as the aqueous medium flows through the tank 19; reaction conditions are monitored at a first location 22 in the tank and the pH of the reaction conditions, based upon a comparison of the information from the monitoring to a fixed standard effected by the computer 23, automatically adjusted to a value between 2 and 10 to optimize reaction conditions; further, the reaction conditions at a second point 26 downstream of the first location in the tank are monitored and the pH adjusted in the same manner as previously described; a substantially solid reaction product precipitates to the bottom of the reaction tank 19 and is removed via drain 31 to be separated by, e.g. filtering or centrifuging, and a second portion of liquid is removed through an outlet 34 and recirculated to the scrubbing tower for further treating of stack gas. |
