A device and process for recovering melamine tail gas using a urea plant

A melamine and urea plant technology, applied in the preparation of organic compounds, urea derivatives, organic chemistry, etc., can solve the problems of insufficient heat utilization rate of melamine tail gas, inconvenient urea production control process, unstable urea production process, etc. , to facilitate the urea production process, reduce the number of flows to different equipment, and achieve high primary utilization
CN104370775BActive Publication Date: 2017-02-15HUAQIANG CHEM GRP
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
HUAQIANG CHEM GRP
Publication Date
2017-02-15

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Abstract

The invention provides a device and technique for recovering melamine exhaust by using a urea unit, relating to the technical field of melamine exhaust recovery treatment. The device comprises an exhaust compressor and a urea unit with a primary decomposing tower, wherein the side wall of the primary decomposing tower corresponding to the bottom of the lower separating section is provided with an exhaust inlet; and the exhaust compressor is communicated with the primary decomposing tower through the exhaust inlet. The technique comprises the following steps: sending pressurized melamine exhaust to the primary decomposing tower, introducing a urea solution heated by a primary heater into the primary decomposing tower, injecting a urea solution in a preseparator into a pre-rectifying section, controlling the urea solution at the outlet of the primary heater at 155-160 DEG C, and cooling the gas-liquid mixture in a methylamine condenser to 90-100 DEG C. The device and technique can well utilize the heat of the melamine exhaust, are stable in the production process and convenient to control, and do not increase energy consumption generated by the urea unit.
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Description

technical field

[0001] The invention relates to the technical field of recovery and treatment of melamine tail gas, in particular to a device and process for recovering melamine tail gas using a urea plant. Background technique

[0002] Usually, melamine tail gas contains 68% to 72% ammonia and 28 to 32% carbon dioxide, which can be used to co-produce soda ash, urea and ammonium bicarbonate. In addition, the temperature of melamine tail gas is generally 165°C to 175°C, making melamine Exhaust gas has extremely high heat utilization value. Therefore, the recovery and utilization of melamine tail gas is of great significance to waste reuse and energy saving and emission reduction.

[0003] At present, due to the obvious excess production capacity of soda ash and ammonium bicarbonate in China, the co-production of urea with melamine tail gas has become the main method of recycling melamine tail gas. The traditional method of using melamine tail gas to co-produce urea mainly i...

Claims

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