| 摘要 |
1,258,410. Controlling exothermal catalytic reactions. CHEMOPROJEKT and CHEMICKE ZAVODY NARODNI PODNIK. 23 Dec., 1968 [22 Dec., 1967], No. 61068/68. Heading B1X. [Also in Division C1] In effecting an exothermal chemical reaction in the presence of catalyst which is present in a reactor in the form of a bed having at least two sections, catalyst constituting at least one section of the bed, but excluding the first section of the bed, is prepared by reduction of catalyst precursor in oxidised form by hydrogen present in gas containing hydrogen and other components for effecting the exothermal reaction, hot reducing gas leaving the first section of the bed, which section consists of catalyst in reduced form, in part being recycled, after being mixed with cooler reducing gas introduced through a nozzle or nozzles of an injector recycling system, through the first section of the bed and in part being passed directly to and through other section or sections of the bed, which section or sections initially contain(s) catalyst precursor in oxidised form, the temperature of the reducing gas entering the other section or at least one of the other sections of the bed being regulated, for example by indirect heat exchange and/or by mixing cooler gas with the reducing gas leaving the preceding section of the bed, to a temperature lower than the temperature of the reducing gas leaving the first section of the bed. The catalyst constituting the first section of the bed is prepared, i.e. reduced from the precursor oxide form, either prior to being placed in the reactor or in situ in the reactor, apparently by an conventional known method, prior to preparation of the catalyst constituting the other section or sections of the bed as described. As illustrated in the drawing, cold reducing gas is passed via line 1, heat exchanger 2 and electric preheater 3 to the nozzle of mixing injector 4 where it mixes with hot reducing gas which has passed through first section 5 of the catalyst bed and recycle line 9; after passing through the first section of the catalyst bed, the resulting mixed gas in part is recycled to the mixing injector via the recycle line and in part is passed successively through further sections 6, 7, 8 of the catalyst bed, through the heat exchanger wherein cold reducing gas is preheated, and through discharge line 14 for further (unspecified) processing. Cold reducing gas is introduced, as required, via lines 10, 11, 12, 13 to regulate the temperature of the gas entering the various sections of the catalyst bed. As exemplified, the exothermal reaction is the synthesis of ammonia from hydrogen and nitrogen in the presence of elemental iron catalyst derived from iron oxide catalyst precursor. |
