System and method for producing melamine

The invention belongs to the technical field of melamine preparation, and relates to a system and a method for producing melamine. The system comprises a fluidized bed reactor, wherein mixed gas generated by the fluidized bed reactor goes into a hot gas cooler, a hot gas filter, a crystallizer, a catcher, a urea scrubber, a gas-liquid separator and a demister successively; the demister is connected with the crystallizer; a molten salt bath is successively connected with a molten salt furnace and the fluidized bed reactor to provide a heat transfer medium; a carrier gas preheater is connected with the fluidized bed reactor and the molten salt bath; molten salt enters the molten salt furnace, the fluidized bed reactor and the carrier gas preheater successively from the molten salt bath and then returns to the molten salt bath; granular urea outside a boundary area enters the lower part of the urea scrubber; part of molten urea flowing from the bottom of the urea scrubber partly enters the upper and middle parts