Associated melamine from carbon ammonium through technique of two-step method under normal pressure

A technology of melamine and step method, which is applied in the field of two-step ammonium bicarbonate co-production process of melamine under normal pressure, can solve problems such as complex operation process, and achieve good economic benefits, low production cost, and less investment in equipment

Inactive Publication Date: 2006-12-06
HOLITECH TECH CO LTD
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  • Abstract
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Problems solved by technology

The disadvantage is that the concentrated ammonia water generated after absorption is circulated into the carbonization tower, and the ammonia gas coming out of the carbonization tower still needs to be absorbed by the purification tower, and the operation process is relatively complicated.

Method used

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  • Associated melamine from carbon ammonium through technique of two-step method under normal pressure

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Embodiment

[0020] The process flow of the present invention is as follows: the raw material urea is blown into the reactor by gas ammonia, and the gas ammonia sent from the circulator is preheated to 350-400 ° C, and then the catalyst is blown to fluidize from the bottom of the reactor, and the catalyst is blown into a fluidized state at 385-400 ° C. At 395°C, urea reacts in the reactor to generate melamine. The reactant comes out from the top of the reactor and enters the air guide absorber with the circulating gas to exchange heat with softened water to generate steam. After the catalyst dust is removed by the external filter, it enters the air for preheating The collector further exchanges heat with the cold air to generate hot air at 130-135°C and sends it to the finished product process as one of the heat sources for drying melamine. The reactants enter the collector to cool down and desublimate naturally, and settle the captured melamine to be refined; The circulating gas from the c...

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Abstract

This invention discloses a two-step process for producing melamine from urea under normal pressure. The method comprises: (1) blowing urea with ammonia into a reactor, mixing with ammonia from a circulation machine, preheating and blowing the catalyst from the bottom of the reactor to fluidize; (2) discharging the reactant from the top of the reactor, removing the catalyst dust by an outer filter, introducing into a collector, cooling naturally and condensing to obtain melamine; (3) purifying the circulation gas from the collector with an absorbing column to absorb carbon dioxide; (4) reacting the mother liquor obtained in step 3 and carbon dioxide obtained by the decarbonization of ammonium bicarbonate to obtain ammonium carbonate; (5) cooling the purified circulation gas, introducing into the circulation machine, concentrating, and passing into the reactor. Compared with present techniques, the method has such advantages as low raw material cost, high profit, easy control, simple process and reliable operation.

Description

technical field [0001] The invention belongs to the technical field of preparing melamine from urea, and in particular relates to a two-step normal-pressure ammonium bicarbonate co-production process for melamine. Background technique [0002] Melamine, also known as melamine (melamine), is an important organic chemical intermediate product, and its main industrial use is to polycondensate with formaldehyde to produce melamine-formaldehyde resin. The production method of melamine is divided into dicyandiamide method and urea method according to raw materials. The raw material of the dicyandiamide method starts with calcium carbide, which consumes a large amount of electric energy, and the source of raw materials is difficult. This method has now been eliminated. [0003] At present, urea is used as raw material in domestic melamine production, and most of its technological process adopts atmospheric pressure dry capture and refining method. The process is generally divided...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D251/54C07D251/60
Inventor 高化忠王兆年高修家唐敬德杨德柱张守河
Owner HOLITECH TECH CO LTD
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