CN111217723A

CN111217723A - Preparation process of ultrafine particle nitroguanidine

Info

Publication number: CN111217723A
Application number: CN201811410905.0A
Authority: CN
Inventors: 吴根龙; 周甦; 杨建亚; 陈雅新
Original assignee: Ningxia Soochow Agrochemical Co ltd
Current assignee: Ningxia Soochow Agrochemical Co ltd
Priority date: 2018-11-24
Filing date: 2018-11-24
Publication date: 2020-06-02

Abstract

The invention provides a preparation process of superfine particle nitroguanidine, which takes guanidine nitrate and concentrated sulfuric acid with 93 percent of small particle content as main raw materials and water as a hydrolysis solvent, and obtains the superfine particle nitroguanidine with stable, economical and effectively reduced pollution by controlling process parameters such as raw material proportion, temperature and the like and matching with a reaction vessel through processes of twice dehydration reaction, hydrolysis reaction, deacidification, rinsing, dehydration, pulping and the like.

Description

Preparation process of ultrafine particle nitroguanidine

Technical Field

The invention relates to the field of chemical industry, in particular to a preparation process of nitroguanidine.

Background

The molecular formula of the nitroguanidine is CH4N4O2, the nitroguanidine is white needle-shaped crystal, and the density is 1.715 g/cm³Slightly soluble in water, usually prepared by dehydration of guanidine nitrate with concentrated sulfuric acid; the high-efficiency smokeless explosive is widely applied to the configuration of explosives and smokeless powder, the detonation velocity is 7650m/s, the work capacity is 104 percent, the brisance is 144 percent, and the high-efficiency smokeless explosive has the advantages of good stability, low sensitivity, close insensitivity to impact and friction and the like; the smaller the particle of nitroguanidine is, the better the performance of the nitroguanidine can be embodied, but the nitroguanidine produced in China at present has larger crystal particles or takes needle-shaped crystals as main crystals due to the problem of the crystal forming process, thereby influencing the performance of the nitroguanidine.

Disclosure of Invention

In view of the above problems, the present invention aims to provide a stable, economical and pollution-reducing process for preparing ultrafine nitroguanidine particles.

The technical scheme adopted by the invention for realizing the technical purpose is as follows: the preparation process of the ultrafine particle nitroguanidine mainly takes guanidine nitrate and concentrated sulfuric acid with 93 percent of small particle content as main raw materials, takes water as a hydrolysis solvent, and specifically comprises the following steps:

a, adding 2500Kg/h of guanidine nitrate from a bin into a 6000L first dehydration reaction kettle made of 316L materials, and simultaneously continuously adding 5000Kg/h of concentrated sulfuric acid from a tank area and materials at the bottom of the kettle; the weight ratio of the nitroguanidine to the concentrated sulfuric acid is 1:1.9-2.0, and the weight ratio of the nitroguanidine to the ice water is 1: 7.5-8.0; the reaction temperature is controlled to be 30-35 ℃ by pumping, the reaction liquid after heat exchange enters from the middle tangent line of the first dehydration reaction kettle, and the reaction materials stay in the first dehydration reaction kettle for reaction for 1.4 hours.

b, adding the reaction material obtained in the step a into a second dehydration reaction kettle which is made of 316L material and 5000 liters through an overflow port, controlling the reaction temperature to be 30-35 ℃, and staying for reaction for 1 hour to finish the dehydration reaction.

c, pumping the dehydration reaction liquid at the temperature of 30-35 ℃ into the immersed impinging stream reactor at the flow rate of 7500Kg/h and the water at the temperature of 5-6 ℃ at the flow rate of 20000Kg/h through a coaxial feeding pipe and a nozzle by a pump, controlling the reaction temperature between 19-21 ℃, impacting oppositely at the center of the reactor to form a highly turbulent impacting area, and staying the reaction materials in the immersed impinging stream reactor for 9-10 minutes.

d, continuously filtering and removing the acid water mother liquor through a belt filter, rinsing with tap water, and dehydrating to obtain the nitroguanidine with the water content of 40%.

e beating the 40% nitroguanidine in a beating tank by using water, dehydrating by using a centrifugal machine, further washing by using a small amount of water until the content of the nitroguanidine is 98.93%, the particle size is less than or equal to 3 mu m, the length is 5-10 mu m, the water content is 25%, 1695Kg/h, the molar yield is as follows: 85.52 percent.

Preferably, in step c, the residence time of the reaction mass in the submerged impinging stream reactor is increased to 30 minutes, resulting in a content: 1709Kg/h of nitroguanidine with 98.87 percent, particle size less than or equal to 2 mu m, length of 1-6 mu m and 25 percent of water, the molar yield is as follows: 86.23 percent.

Preferably, the feeding pipes and the nozzles of the immersed impinging stream reactor are arranged in a plurality of groups in a layered mode, the feeding pipes on the same layer are coaxially arranged in an opposite mode, the nozzles are arranged at the outlet ends of the feeding pipes, the structure, the diameter and the distance of the nozzles are adjustable, the multiple-effect impingement is adopted in the repeated circulation impinging stream reactor, the impinging mixing effect is enhanced, and the micro mixing effect of the reactor is greatly enhanced.

The preparation process of the ultrafine particle nitroguanidine has the advantages that:

1. the molar yield of the ultrafine particle nitroguanidine reaches more than 85 percent; the content of nitroguanidine is more than or equal to 98.0 percent, the grain diameter is less than or equal to 3 mu m, and the length is 1-10 mu m.

2. The continuous dehydration production is realized by using the series full mixed flow reactor; and (3) carrying out hydrolysis reaction by using an immersed impinging stream reactor to prepare the ultrafine-particle nitroguanidine.

3. The automatic instrument is controlled in a centralized way, the process is continuous and automatic, and the process technology is stable and reliable.

Detailed Description

The invention is further illustrated by the following examples:

the first embodiment is as follows:

this example was carried out as follows

a, metering by a solid flow meter in a first dehydration reaction kettle made of 6000 liters of 316L materials, continuously adding 93 percent of guanidine nitrate from small particles of a stock bin at the flow rate of 2500Kg/h, and simultaneously metering by a mass flow meter, continuously adding 5000Kg/h of concentrated sulfuric acid from a tank area, and feeding materials at the bottom of the kettle; the weight ratio of the nitroguanidine to the concentrated sulfuric acid is 1:1.9-2.0, and the weight ratio of the nitroguanidine to the ice water is 1: 7.5-8.0; the passing flow rate is 50M³Pumping of/Hr; the heat exchange is carried out through a cooling heat exchanger, the reaction temperature is controlled to be 30-35 ℃, the reaction liquid after heat exchange enters from the middle tangent line of the first dehydration reaction kettle, and the reaction materials stay in the first dehydration reaction kettle for reaction for 1.4 hours.

The dewatered reaction liquid at c30-35 deg.c is pumped at 7500Kg/h flow rate and water at 5-6 deg.c at 20000Kg/h flow rate through the coaxial feeding pipe and nozzle into the immersed impact flow reactor, and the reactor consists of kettle, coaxial feeding pipe and nozzle, inner circulating impact guide cylinder, propeller and other parts and can realize fluid impact and mixing in the immersed state inside the kettle. Controlling the reaction temperature between 19 and 21 ℃, impacting oppositely at the center of the reactor to form a highly turbulent impact zone, and staying the reaction materials in the immersed impact flow reactor for 9 to 10 minutes; the feeding pipes and the nozzles can be arranged in a plurality of groups in a layered mode, the feeding pipes on the same layer are coaxially arranged in an opposite mode, the nozzles are installed at the outlet ends of the feeding pipes, and the nozzle structure, the diameter and the distance are adjustable.

The preparation process adopts a series-connected full mixed flow reactor to realize continuous dehydration production; carrying out hydrolysis reaction by using an immersed impinging stream reactor to prepare superfine-particle nitroguanidine; the automatic instrument is controlled in a centralized way, the process is continuous and automatic, and the process technology is stable and reliable.

Example two:

the second embodiment is different from the first embodiment in that: in step c, the residence time of the reaction mass in the submerged impinging stream reactor was increased to 30 minutes, resulting in a content: 1709Kg/h of nitroguanidine with 98.87 percent, particle size less than or equal to 2 mu m, length of 1-6 mu m and 25 percent of water, the molar yield is as follows: 86.23 percent.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. A preparation process of superfine particle nitroguanidine mainly uses guanidine nitrate and concentrated sulfuric acid with 93% of small particle content as main raw materials, and water as a hydrolysis solvent, and is characterized in that: the method specifically comprises the following steps:

a, adding 6000 liters of a first dehydration reaction kettle made of 316L materials, continuously adding guanidine nitrate from a stock bin at a flow rate of 2500Kg/h, and simultaneously continuously adding concentrated sulfuric acid from a tank area at a flow rate of 5000Kg/h to obtain a material at the bottom of the kettle; the weight ratio of the nitroguanidine to the concentrated sulfuric acid is 1:1.9-2.0, and the weight ratio of the nitroguanidine to the ice water is 1: 7.5-8.0; the reaction temperature is controlled to be 30-35 ℃ by pumping, the reaction liquid after heat exchange enters from the middle tangent line of the first dehydration reaction kettle, and the reaction materials stay in the first dehydration reaction kettle for reaction for 1.4 hours.

b, adding the reaction material obtained in the step a into a second dehydration reaction kettle which is made of 5000 liters of 316L materials through an overflow port, controlling the reaction temperature to be 30-35 ℃, and staying for reaction for 1 hour to finish the dehydration reaction.

2. The process for preparing ultrafine particulate nitroguanidine according to claim 1, wherein: in step c, the residence time of the reaction mass in the submerged impinging stream reactor was increased to 30 minutes, resulting in a content: 1709Kg/h of nitroguanidine with 98.87 percent, particle size less than or equal to 2 mu m, length of 1-6 mu m and 25 percent of water, the molar yield is as follows: 86.23 percent.

3. The process for preparing ultrafine particulate nitroguanidine according to claim 1, wherein: the inlet pipes and the nozzles of the immersion impinging stream reactor are arranged in a plurality of groups in a layered manner, the inlet pipes on the same layer are coaxially arranged in an opposite manner, the outlet ends of the inlet pipes are provided with the nozzles, and the structure, the diameter and the space of the nozzles are adjustable.