Abstract Catalytic manufacture of melamine from urea by thermal cracking of urea and converting the resulting cracked gases to melamine in the presence of catalysts. The thermal decomposition is carried out in a fluidized bed, the necessary heat being applied by heat exchangers located in the fluidized bed. Conversion of the cracked gases to melamine is effected either in the same fluidized bed, in which case the fluidized solid consists of conventional catalysts, or in a reaction zone remote from said fluidized bed. In the latter case, the solids fluidized consist of catalytically inactive particles, the conversion being carried out in the presence of catalysts in said reaction zone remote from the fluidized bed. In both cases, the urea is fed to the fluidized bed at a point above the heat exchangers.
A PROCESS FOR THECATALYTIC SYNTHESIS OF MELAMINE FROM UREA IN WHICH AREA IS PASSED TO A FLUIDIZED BED WHEREIN IT IS CRACKED AT A TEMPERATURE OF FROM 300* TO 450*C TO FORM ISOCYANIC ACID AND AMMONIA GASES AND WHEREIN SAID GASES ARE REACTED IN THE PRESENCE OF A CATALYST BED AT TEMPERATURE OF FROM 300* TO 450*C TO FORM MELAMINE, THE IMPROVEMENT WHICH COMPRISES SUPPLYING THE HEAT REQUIRED FOR SAID CRACKING STEP INDIRECTLY BY MEANS OF HEAT EXCHANGES LOCATED WITHIN THE FLUIDIZED BED ANDFEEDING UREA TO SAID FLUIDIZED BED AT A POINT ABOVE SAID HEAT EXCHANGERS.
Claim 2
Dependent Claim
96 words
A PROCESS FOR THECATALYTIC SYNTHESIS OF MELAMINE FROM UREA IN WHICH AREA IS PASSED TO A FLUIDIZED BED WHEREIN IT IS CRACKED AT A TEMPERATURE OF FROM 300* TO 450*C TO FORM ISOCYANIC ACID AND AMMONIA GASES AND WHEREIN SAID GASES ARE REACTED IN THE PRESENCE OF A CATALYST BED AT TEMPERATURE OF FROM 300* TO 450*C TO FORM MELAMINE, THE IMPROVEMENT WHICH COMPRISES SUPPLYING THE HEAT REQUIRED FOR SAID CRACKING STEP INDIRECTLY BY MEANS OF HEAT EXCHANGES LOCATED WITHIN THE FLUIDIZED BED ANDFEEDING UREA TO SAID FLUIDIZED BED AT A POINT ABOVE SAID HEAT EXCHANGERS.
Claim 3
Dependent Claim
37 words
A process as set forth in claim 1, wherein thermal cracking and catalytic conversion of the cracked gases are effected in one and the same fluidized bed, the fluidized solids consisting of known catalysts for said conversion.
Claim 4
Dependent Claim
51 words
A process as set forth in claim 1, wherein thermal cracking of the urea is carried out in a fluidized bed comprising catalytically inactive particles and the resulting cracked gases are converted to melamine in the presence of known catalysts in a reaction zone which is remote from said fluidized bed.
Claim 5
Dependent Claim
32 words
A process as set forth in claim 1, wherein the urea is fed at a point above the heat exchangers and at least 1 m below the surface of the fluidized bed.