| 摘要 |
<p>Substances containing a CN bond e.g. hydrocyanic acid and calcium cyanamide are prepared at high temperatures from carboniferous gases and ammonia, at least the ammonia being preheated by the aid of circulating solid, heat carriers which are either ceramic heat carriers impregnated with a copper salt or metallic carriers of copper or copper alloys. The carboniferous gases may also be preheated say with circulating ceramic heat carriers. The ammonia may be heated to say 200 DEG to 400 DEG C. and the carboniferous gas heated to a temperature such that when mixed the gases are at above the reaction temperature. The solid heat carriers may be heated by gases from the reaction zone. In Fig. 1, in the production of calcium cyanamide, fine grain lime from bunker 1 is burnt in furnace 2 by burner 3. The furnace is heated with gas introduced at 4. Air is supplied to burner 3 via a blower and air-preheater 6. The burnt lime is reacted in reactor 11 with 95% carbon monoxide fed in at 12 at 950 DEG C. and pure ammonia fed in at 12 at 600 DEG C. The carbon monoxide is preheated by corondum pebbles in heater 15. Pebbles discharged from heater 15 and cooled to 200 DEG C. are passed to stone heater 18 heated by burning gas from 4 with preheated air from preheater 6 in burner 19. Ammonia is preheated in heater 21 with solid heat carrier balls which are heated in heater 24 by the gas emerging at 800 DEG C. from the reactor 11. In Fig. 2 (not shown) hydrocyanic acid is produced by reacting carbon monoxide, heated with corundum pebbles to 750 DEG C., and ammonia, heated by circulating solid heat carrier balls to 200 DEG C. in the presence of a cerium vanadin catalyst. Nitriles may also be synthesized according to this method.</p> |
