FIELD: chemistry.
SUBSTANCE: invention refers to a method for producing high-grade melamine with low energy consumption by carbamide pyrolysis involving the following working stages: a) dividing a two-phase gas-liquid carbamide pyrolysis product on a fluid flow of crude melamine and the first flow of an anhydrous waste gas containing NH3, CO2 and melamine vapour; b) contacting the above fluid flow with an anhydrous NH3 gas flow and forming the fluid flow of CO2-depleted crude melamine and the second flow of the anhydrous waste gas containing NH3, CO2 and melamine vapour; c) contacting the above first and second flows of the anhydrous waste gas with at least one anhydrous wash and forming a water flow containing melamine, NH3, CO2, and a flow of wet waste gas containing NH3, CO2 and water vapour; d) removing at least a portion of CO2 from the above water flow containing melamine, NH3, CO2 and forming a flow containing CO2 removed and a CO2-depleted water flow containing melamine; e) removing melamine contained in the above fluid flow of CO2-depleted crude melamine and melamine contained in the above CO2-depleted water flow containing melamine by crystallisation with cooling down to form a crystallised melamine flow and a mother solution flow. The present invention also refers to equipment for implementing the above method.
EFFECT: producing high-grade melamine with low energy consumption.
15 cl, 3 dwg, 1 ex
