阅读说明：本技术 硝基复合肥受热分解危险性分级方法 (Method for grading danger of thermal decomposition of nitro compound fertilizer ) 是由 霍明甲 王双全 刘奥林 吴保意 于 2019-04-04 设计创作，主要内容包括：本发明涉及一种硝基复合肥受热分解危险性分级方法,主要解决现有技术中硝基复合肥的分解危险性大小无法判定、安全性好的问题。本发明通过采用一种硝基复合肥受热分解危险性分级方法,采用硝基复合肥分解传播速度测试系统进行颗粒小于2mm的硝基复合肥受热分解危险性分级,所述测试系统包括数据监测及控制系统、传播速度测试设备、安全防护系统的技术方案较好地解决了上述问题,可用于硝基复合肥受热分解危险性分级中。(The invention relates to a method for grading the risk of thermal decomposition of a nitro compound fertilizer, which mainly solves the problems that the decomposition risk of the nitro compound fertilizer can not be judged and the safety is good in the prior art. The invention adopts a method for grading the risk of thermal decomposition of the nitro-compound fertilizer, adopts a nitro-compound fertilizer decomposition and propagation speed test system to grade the risk of thermal decomposition of the nitro-compound fertilizer with the particle size less than 2mm, and adopts the technical scheme that the test system comprises a data monitoring and control system, propagation speed test equipment and a safety protection system to better solve the problems.)

1. A nitro compound fertilizer thermal decomposition risk grading method adopts a nitro compound fertilizer decomposition and propagation speed test system to carry out nitro compound fertilizer thermal decomposition risk grading with the particle size less than 2mm, the test system comprises a data monitoring and control system, propagation speed test equipment and a safety protection system, the data monitoring and control system is used for controlling the start and stop of the heating of the test equipment, collecting and monitoring the temperature data of each thermocouple, monitoring the propagation condition of the peak surface in real time in a video mode and starting the safety protection system to put out a fire once violent reaction occurs; the propagation speed testing equipment comprises an electric heater, a stainless steel box, a cuboid groove and a temperature detector, and the safety protection system mainly comprises a video monitoring and fire extinguisher and is used for video acquisition in the decomposition and propagation process of the nitro-compound fertilizer and the fire extinguishing and cooling effects after the decomposition reaction is finished; when the thermal decomposition risk grading is carried out on the nitro compound fertilizer, the method comprises the following steps:

1) screening, drying and cooling the nitro-compound fertilizer to be detected to be used as a sample;

2) putting the sample into a cuboid groove, putting a stainless steel box provided with an electric heater at one end of the cuboid groove, and installing at least 5 thermocouples in the sample groove;

3) starting control system software, starting heating, and simultaneously monitoring a system to record time and temperature curves of all thermocouples;

4) when one selected thermocouple obviously detects the temperature rise, the control system automatically starts the extinguishing agent to extinguish the fire and reduce the temperature until the temperature of each thermocouple is displayed as the room temperature;

5) calculating the decomposition and transmission performance of the nitro-compound fertilizer according to the temperature curve obtained by testing, carrying out risk classification, and calculating the transmission speed V;

6) decomposition of propagation risk judgment principles: if one selected thermocouple does not detect obvious temperature rise within a specific time, the nitro-compound fertilizer to be detected does not have decomposition and propagation characteristics; otherwise, there is a risk of decomposition propagation.

2. The method for grading risk of thermal decomposition of nitro compound fertilizer according to claim 1, wherein the fire extinguisher is a carbon dioxide fire extinguisher.

3. The method for grading risk of thermal decomposition of a nitro compound fertilizer as claimed in claim 1, wherein the surface of the stainless steel box heated in contact with the nitro compound fertilizer is protected by aluminum foil.

4. The method for grading risk of thermal decomposition of a nitro compound fertilizer as claimed in claim 1, wherein thermocouples are installed one by one at intervals of 150mm and inserted into the sample.

5. The method for grading the dangerousness of thermal decomposition of a nitro-compound fertilizer as claimed in claim 1, wherein when the 5 th thermocouple obviously detects a temperature rise, the control system automatically starts the fire extinguishing agent to extinguish the fire and cool the fire until the temperature of each thermocouple is displayed as room temperature, the decomposition and transmission properties of the nitro-compound fertilizer are calculated according to the temperature curve obtained by the test, the dangerousness grading is carried out, the transmission speed is calculated by adopting the time difference of the 2 nd and 3 rd thermocouples when the highest temperature is acquired, and the calculation formula is V-15/(t ═ t-_3max-t_2max),t_3maxThe time point when the temperature is maximum value collected by the No. 3 temperature sensor; t is t_2maxThe time point when the temperature maximum value is acquired by the No. 2 temperature sensor; (t)_3max-t_2max) The time difference between the maximum temperature values acquired by the No. 3 and No. 2 temperature sensors is represented by the unit of hour, and V is the propagation speed in cm/hour; decomposition of propagation risk judgment principles: if the 5 th thermocouple does not detect the obvious temperature rise within 5 hours, the nitro-compound fertilizer to be detected does not have the decomposition and propagation characteristics; otherwise, there is a risk of decomposition propagation.

6. The method for grading the risk of thermal decomposition of a nitro-compound fertilizer as claimed in claim 1, wherein the nitro-compound fertilizer to be tested is dried in a vacuum drying oven at 60-65 ℃ for 24 hours at a constant temperature before testing, and the dried and cooled sample to be tested is sieved and tested with a part having a particle size of less than 2 mm.

7. The method for grading risk of thermal decomposition of a nitro-compound fertilizer as claimed in claim 1, wherein the rectangular tank is opened at the top, is made of stainless steel wire mesh and has meshes with a width of 0.3-0.5 mm, and is placed on the support.

8. The method for grading risk of thermal decomposition of nitro compound fertilizer according to claim 1, wherein the monitoring and control system is connected with an electric heater, a video monitor, a fire extinguisher and a thermocouple.

9. The method for grading risk of thermal decomposition of nitro compound fertilizer according to claim 1, wherein the thermocouple is a K-type thermocouple.

10. The method for grading risk of thermal decomposition of a nitro compound fertilizer as claimed in claim 9, wherein a thermocouple is installed in the sample tank after the sample tank is filled with the sample.

Technical Field

The invention relates to a method for grading the danger of thermal decomposition of a nitro-compound fertilizer, which is used for evaluating the stability of the nitro-compound fertilizer when being heated under the condition of transportation or storage and establishing a method for grading the danger of the nitro-compound fertilizer based on the decomposition propagation speed by testing the decomposition propagation speed of the nitro-compound fertilizer when being heated.

Background

The nitro compound fertilizer is a high-concentration compound fertilizer containing ammonium nitrogen, nitrate nitrogen and available phosphorus and potassium, is a new fertilizer variety developed in China in nearly 10 years, and has a good development prospect. After the agricultural ammonium nitrate is listed as an agricultural explosive in 2002 for management, ammonium nitrate manufacturers modify ammonium nitrate to lose explosiveness and be unreduced, and then produce the nitro-compound fertilizer. Nevertheless, the output of nitro-compound fertilizers in China is still very small. According to the related statistical data, the proportion of nitrate nitrogen fertilizer in the total nitrogen fertilizer is as follows: france 76%, germany 14%, netherlands 54%, uk 39%, poland 64%, russia 27%, ukraine 22%, usa 31%, egypt 15%, africa 100%, average 14% worldwide, while china only 3%. Therefore, the nitro compound fertilizer has better market prospect in China. In addition, China is the biggest nitric acid producing country in the world, and the situation of the shortage of sulfur resources can be relieved by using nitric acid to decompose phosphate rock to prepare the nitro-compound fertilizer. Although the nitro compound fertilizer has become an industrial development hotspot, the product needs to be developed healthily, and the restriction needs to be broken through in several aspects, the first restriction is a safety restriction, and the second restriction is green. The nitro compound fertilizer takes ammonium nitrate as a nitrogen source, while the ammonium nitrate at normal temperature is stable, but can seriously affect and accelerate the change of physical and chemical properties along with the rise of temperature and the catalytic action of certain substances, and even can cause the extreme instability of a system to cause explosion; even if the explosion does not occur, the exothermic amount of the decomposition reaction and the generated highly toxic gas can cause serious safety accidents. However, many enterprises producing nitro compound fertilizers are agricultural fertilizer production enterprises developed from production of granular compound fertilizers, the importance of the dangerousness and safety production in ammonium nitrate production is not well understood, and many enterprises are in succession in different degrees of mixing tank safety accidents, even casualties are caused.

Through national standard and patent search, the nitro compound fertilizer has the quality standard, anti-knock performance test methods and some preparation methods, such as standard HT/T4851-. The analysis finds that the quality standard of the nitro-compound fertilizer mainly emphasizes the product quality and related parameters, the patent is mainly used for the preparation method of the high-stability nitro-compound fertilizer, only WJ/T9050-. The patent and the standard of 'agricultural ammonium nitrate antiknock performance test method and judgment' have no repeatability, do not use detonators, are very safe and are easy to realize.

Disclosure of Invention

The invention aims to solve the technical problems that the decomposition risk of the nitro-compound fertilizer in the prior art cannot be judged and the safety is poor, and provides a novel method for grading the thermal decomposition risk of the nitro-compound fertilizer, which has the advantage of good safety.

In order to solve the problems, the technical scheme adopted by the invention is as follows: a nitro compound fertilizer thermal decomposition risk grading method adopts a nitro compound fertilizer decomposition and propagation speed test system to carry out nitro compound fertilizer thermal decomposition risk grading with the particle size less than 2mm, the test system comprises a data monitoring and control system, propagation speed test equipment and a safety protection system, the data monitoring and control system is used for controlling the start and stop of the heating of the test equipment, collecting and monitoring the temperature data of each thermocouple, monitoring the propagation condition of the peak surface in real time in a video mode and starting the safety protection system to put out a fire once violent reaction occurs; the propagation speed testing equipment comprises an electric heater, a stainless steel box, a cuboid groove and a temperature detector, and the safety protection system mainly comprises a video monitoring and fire extinguisher and is used for video acquisition in the decomposition and propagation process of the nitro-compound fertilizer and the fire extinguishing and cooling effects after the decomposition reaction is finished; when the thermal decomposition risk grading is carried out on the nitro compound fertilizer, the method comprises the following steps:

1) screening, drying and cooling the nitro-compound fertilizer to be detected to be used as a sample;

2) putting the sample into a cuboid groove, putting a stainless steel box provided with an electric heater at one end of the cuboid groove, and installing at least 5 thermocouples in the sample groove;

3) starting control system software, starting heating, and simultaneously monitoring a system to record time and temperature curves of all thermocouples;

4) when one selected thermocouple obviously detects the temperature rise, the control system automatically starts the extinguishing agent to extinguish the fire and reduce the temperature until the temperature of each thermocouple is displayed as the room temperature;

5) calculating the decomposition and transmission performance of the nitro-compound fertilizer according to the temperature curve obtained by testing, carrying out risk classification, and calculating the transmission speed V;

6) decomposition of propagation risk judgment principles: if one selected thermocouple does not detect obvious temperature rise within a specific time, the nitro-compound fertilizer to be detected does not have decomposition and propagation characteristics; otherwise, there is a risk of decomposition propagation.

In the above technical scheme, preferably, the fire extinguisher is a carbon dioxide fire extinguisher.

In the technical scheme, preferably, the surface of the stainless steel box, which is contacted and heated with the nitro-compound fertilizer, is protected by an aluminum foil.

In the above technical solution, preferably, one thermocouple is installed every 150mm and inserted into the sample.

In the above technical solution, preferably, when the 5 th thermocouple obviously detects a temperature increase, the control system automatically starts the fire extinguishing agent to extinguish the fire and cool the fire until the temperature of each thermocouple is displayed as room temperature, calculates the decomposition and propagation properties of the nitro-compound fertilizer according to the temperature curve obtained by the test, and carries out risk classification, wherein the propagation speed is calculated by using the time difference between the 2 nd and 3 rd thermocouples when the highest temperature is acquired, and the calculation formula is V ═ 15/(t_3max-t_2max),t_3maxTemperature collected by No. 3 temperature sensorTime point at the maximum value of degree; t is t_2maxThe time point when the temperature maximum value is acquired by the No. 2 temperature sensor; (t)_3max-t_2max) The time difference between the maximum temperature values acquired by the No. 3 and No. 2 temperature sensors is in unit of hour; v is the propagation velocity, cm/hour; decomposition of propagation risk judgment principles: if the 5 th thermocouple does not detect the obvious temperature rise within 5 hours, the nitro-compound fertilizer to be detected does not have the decomposition and propagation characteristics; otherwise, there is a risk of decomposition propagation.

In the technical scheme, preferably, the nitro-compound fertilizer to be tested is dried in a vacuum drying oven at 60-65 ℃ for 24 hours at constant temperature before testing, and the dried and cooled sample to be tested is sieved and tested by adopting a part with the particle size of less than 2 mm.

Among the above-mentioned technical scheme, preferably, cuboid groove top opening, the material is made for stainless steel wire mesh, has the mesh, and the mesh is wide 0.3 ~ 0.5mm, and the cuboid groove is placed on the support.

In the above technical scheme, preferably, the monitoring and control system is connected with the electric heater, the video monitoring device, the fire extinguisher and the thermocouple.

In the above technical solution, preferably, the thermocouple is a K-type thermocouple, and after the cuboid groove is filled with the sample, the thermocouple is installed in the sample groove.

The invention provides a method for testing the stability of a nitro-compound fertilizer when the nitro-compound fertilizer is heated to decompose, so as to evaluate whether the nitro-compound fertilizer spreads to the whole packaging piece due to local thermal decomposition, and provides a method for grading the risk of the nitro-compound fertilizer when the nitro-compound fertilizer is heated to decompose, which is mainly suitable for the links of transport and storage of the nitro-compound fertilizer. Specific test equipment and method are provided for the decomposition and propagation dangers of the nitro compound fertilizer, and the problem that the test method is lacked for the decomposition and propagation dangers of the nitro compound fertilizer in the prior art is solved; the specific decomposition risk grading method is provided for the nitro-compound fertilizer, the problem that the decomposition risk of the nitro-compound fertilizer cannot be judged in the past is solved, the safety is good, and a better technical effect is achieved.

Drawings

FIG. 1 is a schematic diagram of a decomposition and propagation testing system of the nitro-compound fertilizer.

In fig. 1, a data monitoring and control system; 2 electric heater stainless steel box; 3, a cuboid groove; 4, carbon dioxide fire extinguishers; 5, monitoring a video; 6 thermocouple.

The present invention will be further illustrated by the following examples, but is not limited to these examples.

Detailed Description

[ example 1 ]

A nitrocompound fertilizer thermal decomposition risk grading method adopts a nitrocompound fertilizer decomposition and propagation speed testing system to carry out nitrocompound fertilizer thermal decomposition risk grading with the particle size less than 2mm, as shown in figure 1, wherein the testing system comprises a data monitoring and control system, propagation speed testing equipment and a safety protection system.

The data monitoring and control system is used for controlling the heating start and stop of the test equipment, collecting and monitoring the temperature data of each thermocouple, monitoring the peak surface propagation condition in real time through video, and starting the safety protection system to extinguish fire once violent reaction occurs.

Propagation speed test equipment includes electric heater, stainless steel box, cuboid groove and thermodetector, and the inside size is 750mm long wide 250mm high 250 mm's cuboid groove, top opening. The square groove is made of a stainless steel wire mesh and is provided with meshes, the width of each mesh is about 0.3-0.5 mm, the thickness of each stainless steel wire is 1.0mm, the cuboid groove is placed on a proper support, and the support structure does not need to be made. If the particle size composition of the nitro-compound fertilizer is such that a large proportion of the fertilizer leaks through the screen of the tank, a smaller screen tank should be used and sufficient heat should be supplied and maintained during heating to form a uniform decomposition front. The electric heating power is 250 watts, the electric heater is arranged in a stainless steel box with the thickness of 5mm and the thickness of 245mm multiplied by 15mm, and the surface of the stainless steel box, which is contacted and heated with the nitrofertilizer, can be protected by aluminum foil. The thermocouple is a K-type thermocouple.

The safety protection system mainly comprises a video monitoring and carbon dioxide fire extinguisher, and is used for video acquisition in the decomposition and propagation process of the nitro-compound fertilizer and the fire extinguishing and cooling effects after the decomposition reaction is finished; when the nitrocompound fertilizer is subjected to thermal decomposition risk classification,

the specific operation procedure is as follows:

sieving the nitro-compound fertilizer to be tested, using the part with the particle size smaller than 2mm for testing, drying the sample in a vacuum drying oven at the constant temperature of 65 ℃ for 24 hours, and cooling for later use;

filling the dried sample into a cuboid groove, placing a stainless steel box provided with an electric heater at one end of the cuboid groove, protecting the heated surface of the stainless steel box in contact with the nitrofertilizer by using aluminum foil, installing 5 thermocouples in the sample groove, installing one thermocouple every 150mm, inserting the thermocouple into the sample, wherein the insertion depth is 200mm, and the numbers are 1#, 2#, 3#, 4#, and 5 #;

step three, starting control system software, starting heating, wherein the heating time is 15 minutes, the heating is automatically controlled by the control system, and meanwhile, the monitoring system records the time and the temperature curve of each thermocouple, and the recording time is 5 hours;

step four, when the 5# thermocouple obviously detects the temperature rise, the control system automatically starts the extinguishing agent to extinguish the fire and reduce the temperature until the temperature of each thermocouple is displayed as the room temperature;

step five, calculating the decomposition and transmission performance of the nitro-compound fertilizer according to the temperature curve obtained by testing, carrying out risk classification, calculating the transmission speed by adopting the time difference of the highest temperature collected by the 2# thermocouple and the 3# thermocouple, and calculating the formula as V15/(t)_3max-t_2max),t_3maxThe time point when the temperature is maximum value collected by the No. 3 temperature sensor; t is t_2maxThe time point when the temperature maximum value is acquired by the No. 2 temperature sensor; (t)_3max-t_2max) The time difference between the maximum temperature values acquired by the No. 3 and No. 2 temperature sensors is in unit of hour; v is the propagation velocity, cm/hour.

Decomposition of propagation risk judgment principles:

if the 5# thermocouple does not detect the obvious temperature rise within 5 hours, the nitro-compound fertilizer to be detected does not have the decomposition and propagation characteristics; otherwise, there is a risk of decomposition propagation.

The principle of risk size of the decomposition propagation is shown in table 1.

TABLE 1

Propagation velocity (cm/h)	Risk rating	Description of dangerous conditions
			0＜V≤15	1	Weak danger of decomposition and propagation
15＜V≤25	2	Risk of propagation of decomposition etc
			25＜V≤75	3	High risk of decomposition and propagation