A method for reducing biuret content in industrial urea

A urea neutralization and biuret technology, applied in chemical instruments and methods, preparation of urea derivatives, preparation of organic compounds, etc., can solve the problems of high production cost, high energy consumption, and difficulty in industrial realization, and achieve low cost , the effect of simple equipment

Active Publication Date: 2017-10-13
DALIAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Chinese patent application CN102584635A discloses a method for preparing urea for vehicles, in which urine from a urea workshop is used as raw material, and impurities are removed by recrystallization, but this method consumes a lot of energy, and the crystallization process is difficult to control, making it difficult to realize industrially
Chinese patent application CN101695669A discloses a method for preparing urea solution for vehicles, which follows the recrystallization method and adopts the technical route of mixing pure water and urea, absorbing activated carbon, cooling crystallization, dissolving crystals and filtering to obtain urea solution for vehicles, but The problem with this method is that the energy consumption of recrystallization is high, the introduction of activated carbon for adsorption increases the consumption of raw materials, and the production cost is high

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] (1) Select industrial urea as the raw material, detect according to the national standard GB / T 2441.2-2010, and the biuret content is 0.915%;

[0023] (2) Prepare urea (g): absolute ethanol (ml) = 1:1.8;

[0024] (3) Extract for 3 hours at 25°C (water bath), rotation speed 400r / min, and airtight conditions;

[0025] (4) suction filtration, room temperature drying to constant weight;

[0026] (5) Pack the dried urea into a ziplock bag, and then put it into a desiccator.

[0027] Take 5g of extracted and dried urea each time, do three parallel tests according to the national standard GB / T 2441.2-2010, take the average value of the test results, and the biuret content in urea is reduced from the initial 0.915% to 0.806%.

Embodiment 2

[0029] (1) Select industrial urea as the raw material, detect according to the national standard GB / T 2441.2-2010, and the biuret content is 0.915%;

[0030] (2) Prepare urea (g): absolute ethanol (ml) = 1:1.8;

[0031] (3) Extract for 3 hours at 30°C (water bath), rotation speed 400r / min, and airtight conditions;

[0032] (4) suction filtration, room temperature drying to constant weight;

[0033] (5) Pack the dried urea into a ziplock bag, and then put it into a desiccator.

[0034] Take 5g of extracted and dried urea each time, do three parallel tests according to the national standard GB / T 2441.2-2010, take the average of the test results, and the biuret content in urea is reduced from the initial 0.915% to 0.738%.

Embodiment 3

[0036] (1) Select industrial urea as the raw material, detect according to the national standard GB / T 2441.2-2010, and the biuret content is 0.915%;

[0037] (2) Prepare urea (g): absolute ethanol (ml) = 1:1.8;

[0038] (3) Extract for 3 hours at 35°C (water bath), rotation speed 400r / min, and airtight conditions;

[0039] (4) suction filtration, room temperature drying to constant weight;

[0040] (5) Pack the dried urea into a ziplock bag, and then put it into a desiccator.

[0041] Take 5g of extracted and dried urea each time, and do three parallel tests according to the national standard GB / T 2441.2-2010. The test results are averaged, and the biuret content in urea is reduced from the initial 0.915% to 0.708%.

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Abstract

The invention belongs to the field of chemical industry and provides a method for reducing the content of biuret in industrial urea. Use industrial urea as raw material, anhydrous methanol or ethanol as extraction agent, add extraction agent to the raw material; extract under continuous stirring condition, extraction temperature is 20-50°C, extraction time is 1-10h, extraction temperature difference is 3 ~10°C; suction filtration, room temperature drying to constant weight, the purified urea is obtained; the biuret content in the industrial urea is 0.86%-0.94%; the whole system of the present invention is simple and easy to implement, with simple equipment , Low cost advantage. The invention adopts the hot alcohol extractant to treat the biuret, and has the characteristics of energy saving and environmental protection compared with the heating method and the degradation method. Due to the use of industrial urea, the present invention has advantages in terms of material supply and cost.

Description

technical field [0001] The invention belongs to the field of chemical industry and relates to a method for reducing the content of biuret in industrial urea. Background technique [0002] Nitrogen oxides (NO x ) is the main harmful component in motor vehicle exhaust, of which heavy-duty diesel vehicle emissions account for about 60%. Selective Catalytic Reduction (SCR) technology using urea as reductant has high efficiency NO x SCR catalyst has a strong ability to resist sulfur poisoning, and it has been widely used in Europe and other developed countries and regions as an important means to control vehicle diesel engine exhaust emissions. Since my country's emission regulation system adopts the European regulation system, considering my country's national conditions and the convenience of technology transplantation, my country's automakers and diesel engine companies tend to adopt SCR technology as the main technology to meet the requirements of my country's National IV a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C273/16
Inventor 张晓鹏崔跃宗贺高红李卓峰
Owner DALIAN UNIV OF TECH
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