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Method for shifting ammonia in diphenyl urea reaction system by nitrogen

A technology of diphenylurea and reaction system, applied in the field of ammonia gas, can solve problems such as clogging and affecting reaction, and achieve the effects of solving easy clogging, improving production efficiency and maintenance cost

Active Publication Date: 2013-04-24
PETROCHINA CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

As the reaction progresses in the system, diphenylurea continuously precipitates out at the outlet 3 of the nitrogen pipeline and sticks to the outlet, causing it to be blocked and affecting the progress of the reaction.

Method used

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  • Method for shifting ammonia in diphenyl urea reaction system by nitrogen
  • Method for shifting ammonia in diphenyl urea reaction system by nitrogen

Examples

Experimental program
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Effect test

Embodiment 1

[0015] refer to figure 2 , 3 mol of urea and 15 mol of aniline are added from feed port 1 of tank reactor 4 with a capacity of 3 liters respectively, and the tank is opened for heating and stirring, so that urea and aniline are reacted in the reactor, the reaction pressure is normal pressure, and the reflux condenser 5 pass cooling water, and the reaction temperature is controlled at 160°C. The stirring speed is 100 rpm, and the nitrogen pressure in the nitrogen pipeline 2 is controlled at 3-6kg / cm 2 , keep the nitrogen flow at 12 liters / hour, nitrogen is discharged from the gas extraction port 3, the outlet inner diameter is 100um, and the reaction time of nitrogen flow is 3 hours. During the reaction, the nitrogen gas extraction port is not blocked, and the nitrogen gas is discharged from the 5 top of the reflux condenser. After ammonia-containing nitrogen gas is absorbed by the ammonia gas absorption system 6, the remaining nitrogen gas is discharged to the outside throug...

Embodiment 2

[0018] refer to figure 2 , 3 mol of urea and 18 mol of aniline are respectively added from feed port 1 of tank reactor 4 with a capacity of 3 liters, and the tank is opened for heating and stirring, so that urea and aniline are reacted in the reactor, the reaction pressure is normal pressure, and the reflux condenser 5 through cooling water, the reaction temperature is controlled at 170°C, the speed of the agitator is 120 rpm, and the nitrogen pressure in the nitrogen pipeline 2 is controlled at 3-6kg / cm 2 , keep the nitrogen flow at 15 liters / hour, nitrogen is discharged from the gas extraction port 3, the outlet inner diameter is 300um, and the reaction time of nitrogen flow is 2.5 hours. During the reaction, the nitrogen gas extraction port is not blocked, and the nitrogen gas from the top of the reflux condenser 5 comes out After ammonia-containing nitrogen gas is absorbed by the ammonia gas absorption system 6, the remaining nitrogen gas is discharged to the outside thro...

Embodiment 3

[0021] refer to figure 2 , 3 mol of urea and 24 mol of aniline are added from feed port 1 of tank reactor 4 with a capacity of 3 liters respectively, and the tank is opened for heating and stirring, so that urea and aniline are reacted in the reactor, the reaction pressure is normal pressure, and the reflux condenser 5. Start to pass cooling water, control the reaction temperature at 175°C, the speed of the stirrer at 220 rpm, and control the nitrogen pressure in the nitrogen pipeline 2 at 3-6kg / cm 2 , keep the flow rate of nitrogen at 10 liters / hour, nitrogen is discharged from stripping outlet 3, and the inner diameter of the outlet is 300um. The nitrogen flow time for the reaction is 4 hours. During the reaction process, the outlet of the nitrogen gas is not blocked, and the ammonia-containing nitrogen gas that comes out from the upper part of the reflux condenser 5 passes through the ammonia gas absorption system 6 and absorbs the ammonia gas, and the remaining nitrogen g...

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Abstract

The invention relates to a method for shifting ammonia in a diphenyl urea reaction system by nitrogen. A nitrogen pipeline with the pressure resistance of 10-20kg / cm<2> is introduced into a reactor from the upper part of the reactor; a gas stripping outlet of the nitrogen pipeline is arranged between the lower part of a stirring paddle and the bottom of the reactor; the gas stripping outlet formshole shrinkage; the diameter of a hole ranges from 100 microns to 1mm; the nitrogen flow is 3 to 5 times of reactor size per hour; the reaction nitrogen charging time is 2-4 hours; under the same process condition, the consumption of nitrogen is reduced by 4-6L / kg DPU compared with the traditional method; and the diphenyl urea yield is improved to 96-99 percent by more than 6 percent. The invention has the advantages of high gas stripping efficiency and difficult blockage of the gas stripping outlet of the nitrogen pipeline.

Description

technical field [0001] The invention relates to a method for removing ammonia gas in a diphenylurea reaction system by using nitrogen gas. Background technique [0002] The method of preparing diphenylurea (DPU) by direct reaction of urea and aniline, using nitrogen to remove the by-product ammonia to prepare diphenylurea, has the characteristics of high yield and no equipment corrosion. The reaction is carried out under normal pressure and excessive aniline carried out under, such as figure 1 shown. Urea and aniline are fed into the reactor 4 from the feed port 1 to react, and the reaction product is released from the product discharge port 7 at the bottom of the reactor 4 . The nitrogen pipeline 2 leads into the reactor 4 and is inserted into the position below the liquid level of the reaction material to above the stirring paddle. The inner diameter of the hole 3 of the gas extraction port of the nitrogen pipeline is the same as that of the nitrogen pipeline without dia...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C275/28C07C273/18
Inventor 陈蓝天展江宏徐新良王公应王越龚涛曾毅陈国强康涛郭新军聂宏元冯丽梅
Owner PETROCHINA CO LTD