| 摘要 |
An integrated process for the manufacture of melamine in combination with the manufacture of urea is disclosed, wherein the urea product from the urea synthesis unit is used as feed to the melamine synthesis unit. In the process described, the ammonia and carbon dioxide by-products from the melamine plants are processed by condensing the same to form a dilute solution of ammonium carbamate and ammonia and desorbing the resulting solution at urea synthesis pressures, to release a major part of the carbon dioxide, and passing the resulting gaseous mixture containing ammonia and carbon dioxide with only small amounts of water vapor directly to the high pressure urea synthesis unit. Procedures for suitably recovering and using the heat energy released during the various chemical reactions and evaporation steps are also described. |
