Preparation method of vehicle urea

A technology for urea and urea for vehicles is applied in separation methods, preparation of urea derivatives, chemical instruments and methods, etc., which can solve the problems of complicated and complicated preparation processes and high production costs, reduce environmental pollution, high yield and save production. cost effect

Inactive Publication Date: 2017-12-01
四川金素环保科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The invention provides a method for preparing urea for vehicles, which is used to solve the technical problems existing in the prior art: the preparation process is cumbersome and complicated, and the production cost is high

Method used

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  • Preparation method of vehicle urea
  • Preparation method of vehicle urea

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] A method for preparing urea for vehicles, such as Figure 1~3 shown, including the following steps,

[0037] S1: Synthesize ammonia and carbon dioxide to obtain molten urea with a mass concentration of 80% and a mass percentage of diuresis less than or equal to 0.25%;

[0038] S2: pass the desalted water through the purified water equipment to obtain purified water with a resistivity of 18-20MΩ·cm;

[0039] S3: Add the molten urea in S1 and the purified water in S2 into the batching tank at the same time at a ratio of 1:1.5, and stir for more than 30 minutes to obtain a urea solution with a mass concentration of 31.5% to 32%;

[0040] S4: By fine-tuning the amount of the above-mentioned molten urea or purified water, a urea solution with a mass concentration of 32.5% is obtained, and the urea solution with this mass concentration is crude urea;

[0041] S5: obtaining urea for vehicles by filtering the crude urea;

[0042] S6: transporting the vehicle urea to the fini...

specific Embodiment approach

[0043] Specific implementation method: S1: use the intermediate product molten urea of ​​the urea production plant as raw material to prepare molten urea, the specific steps of preparing molten urea, S11: send the raw material ammonia and carbon dioxide into the urea synthesis tower in a ratio of 4:1, and React at 20MPa and 180°C to obtain a reaction solution;

[0044] S12: The reaction liquid contains urea, methylamine, and excess ammonia, wherein the methylamine in the reaction liquid is decomposed and recovered by air stripping, and the ammonia is recycled through a recovery device. Finally, the reaction liquid is pre-concentrated in a vacuum and separated by one-stage evaporation to obtain a mass concentration It is 80%, 130°C, and the mass percentage of diuresis is equal to 0.25% of molten urea; the molten urea is placed in the urea solution tank, and the urea solution tank is connected with a urea solution pump, and the molten urea is transported to the batching tank thro...

Embodiment 2

[0054] Specific implementation method: S1: use the intermediate product molten urea of ​​the urea production plant as raw material to prepare molten urea, the specific steps of preparing molten urea, S11: send the raw material ammonia and carbon dioxide into the urea synthesis tower in a ratio of 4:1, and React at 20MPa and 200°C to obtain a reaction solution;

[0055] S12: The reaction liquid contains urea, methylamine, and excess ammonia, wherein the methylamine in the reaction liquid is decomposed and recovered by air stripping, and the ammonia is recycled through a recovery device. Finally, the reaction liquid is pre-concentrated in a vacuum and separated by one-stage evaporation to obtain a mass concentration It is 80%, 130°C, and the mass percentage of diuresis is equal to 0.25% of molten urea; the molten urea is placed in the urea solution tank, and the urea solution tank is connected with a urea solution pump, and the molten urea is transported to the batching tank thro...

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Abstract

The invention discloses a preparation method of vehicle urea. The preparation method comprises the following steps: (S1) synthesizing ammonia and carbon dioxide so as to obtain fused urea, wherein the mass concentration of the fused urea is 80%, and the mass percentage of biuret is less than or equal to 0.25%; (S2) treating desalted water by virtue of water refining equipment, so as to obtain refined water with a resistivity of 18Mohm.cm-20Mohm.cm; (S3) simultaneously adding the fused urea obtained in the step (S1) and the refined water obtained in the step (S2) into a batching tank in a proportion of 1 to 1.5, stirring for 30 minutes or longer, so as to obtain a urea solution with a mass concentration of 31.5%-32%; (S4) finely adjusting the amount of the fused urea or the refined water, so as to obtain the urea solution with a mass concentration of 32.5%, namely crude urea; (S5) filtering the crude urea so as to obtain vehicle urea; and (S6) conveying the vehicle urea into a finished product tank, and pumping the vehicle urea into a filling machine by virtue of a finished product pump, so as to obtain the finished vehicle urea. By utilizing the fused urea as the raw material, the vehicle urea with relatively high quality is obtained.

Description

technical field [0001] The invention relates to the technical field of chemical production technology, in particular to a method for preparing urea for vehicles. Background technique [0002] At present, NOx exhaust emissions from diesel vehicles use selective catalytic reduction reaction to achieve standard emissions, relying on high-temperature urea for vehicles to divide into ammonia and carbon dioxide, and ammonia reduces NOx to nitrogen and water under the action of a catalyst to reduce environmental pollution , which is the SCR technology commonly used in the world, but most of the methods for producing urea for vehicles are to obtain the finished product by purifying high-purity urea crystals and then preparing and filtering. [0003] Chinese patent application CN201510506558.1 discloses a production process for vehicle urea solution. Although urine is used to produce vehicle urea, the urine must be cooled to form a crystal suspension in the crystallizer, and the susp...

Claims

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Application Information

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IPC IPC(8): C07C273/04B01D53/94B01D53/56
CPCB01D53/9418B01D2258/012C07C273/04Y02P20/141
Inventor 郭志刚王明权蒲毅余波邓云李泽宇
Owner 四川金素环保科技有限公司
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