A low-carbon and nitrogen-rich ammonium dinitramide liquid propellant and its preparation method and application

Abstract

The present invention provides a low-carbon nitrogen-rich ammonium dinitramide liquid propellant and a preparation method and application thereof, belonging to the field of energetic materials, and the formula and mass fraction ratio of the propellant are: 35-70% ammonium dinitramide, 10-40% low-carbon nitrogen-rich compound, and 10-30% water. The present invention overcomes the defect of insufficient pulse ignition start times of ammonium dinitramide liquid propellant in the prior art, introduces nitrogen-rich ion salts with lower carbon content as fuel in the formula, solves the problem of catalyst carbon deposition poisoning caused by high carbon content of the propellant, realizes a significant increase in the number of pulse working times, and is particularly suitable for long-term on-orbit attitude and orbit control mission requirements of large satellites. The method has easy raw materials, simple synthesis and purification processes, and is convenient for engineering applications.

Description

Technical Field

[0001] The invention relates to a low-carbon and nitrogen-rich ammonium dinitramide liquid propellant and a preparation method and application thereof, belonging to the field of energetic materials. Background Art

[0002] Liquid propellant has the advantages of high calorific value, large specific impulse, easy adjustment of thrust, and multiple ignition and starting, and is widely used in various spacecrafts such as satellites, spacecrafts, rockets, etc. The monopropellant used now is still mainly hydrazine compounds (anhydrous hydrazine, single push-3, etc.), and has been more than 60 years. Although it shows good combustion efficiency and application performance, they all have the defects of easy carcinogenicity, strong corrosion, and poor safety. If "running, emitting, dripping, and leaking" are improperly handled, it will seriously endanger the life safety of the staff, and it will also cause environmental pollution, and it needs complicated ground support and maintenance system, which affects equipment response performance (the research progress of Swedish ADN-based monopropellant liquid green thruster, Jiang Xiaocun, Liu Xiao, Si Yan, Liu Jifang, Propulsion Technology, 2012, 6, 79-83). According to the U.S. report, more than 200 technical experts have been killed and injured due to toxic hydrazine liquid propellant, and all casualties in the aerospace field in recent years have been mostly related to toxic hydrazine propellant. With the continuous development of aerospace technology and people's increasing requirements for environmental protection, the research and development of non-toxic, pollution-free, high-energy-density green liquid propellants to replace traditional hydrazine propellants has become a cutting-edge technology field that countries are competing to develop.

[0003] Ammonium dinitramide (ADN) is a high energy density material first synthesized by the Soviet Union in the 1970s. It has the advantages of being non-toxic, pollution-free, and having low characteristic signals. It is used to replace ammonium perchlorate in solid propellants and has been used in Baiyang series equipment (Preparation of ADN and its application in unit propellants, Chemical Propellants and Polymer Materials, 2017, 15, 39-53). The molecular formula of ADN is NH4N(NO2)2, the oxygen balance is +25.79%, the heat of formation is -148kJ / mol, the solubility at 20°C is 355g / 110g water, and the median lethal dose in mice is LD50. 50The concentration of ADN liquid propellant is 823mg / kg, which is much higher than 60mg / kg of hydrazine. It is a low-toxic substance and is expected to replace hydrazine propellant in the attitude and orbit control power system of aircraft. The U.S. Air Force Research Laboratory, Swedish Aviation Corporation and Swedish Defense Research Agency have been conducting research on the formulation of ADN liquid propellant for 20 years. Finally, two systems that can be used in practice were obtained: LMP-103S (composed of 63.0% ADN, 18.4% methanol and 18.6% ammonia water) and FLP-106 (composed of 64.6% ADN, 23.9% water and 11.5% N-methylformamide). In 2010, the PRISMA satellite using LMP-103S ADN liquid propellant successfully made its first flight and completed relevant test projects in orbit for five years, fully demonstrating the great potential of ADN liquid propellant to replace toxic hydrazine (Flight demonstration of newthruster and green propellant technology on the PRISMA satellite, K.Anflo, R. Acta Astronautica, 2009, 65, 1238-1249; Lab-scale ballistic and safety property investigations of LMP-103S, JC Thomas, FA Rodriguez, Combustion and Flame, 2023, 253, 112810). As of August 2024, ADN liquid propellant has been promoted and applied to many satellites such as SkySat constellation, ELSA-d satellite, NROL-111, Argomoon, etc. (New technologies for ammoniumdinitramide based monopropellant thrusters-The project RHEFORM, M.Negri, M.Wilhelm, C.Hendrich, Acta Astronautica 2018, 143, 105-117, Research progress on the catalytic and thermal decomposition of ammonium dinitramide, RSC Advances, 2024, 3636-3646); currently, the research and development of 200N-600N high-thrust ADN propellant technology is mainly carried out around the mission requirements of the upper stage of the Ariane-5 launch vehicle of the European Space Agency.

[0004] In 2006, the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, took the lead in China to carry out research on ADN liquid propellant, independently developed ADN high-purification preparation technology (CN202111293742.4, CN202111291952.X), and established a comprehensive performance test and analysis method for propellants under simulated space environment conditions; the developed ADN liquid propellant (AMP-112-I type) was successfully launched with the Shijian 17 satellite in November 2016 and successfully completed the in-orbit test, marking the transition of my country's satellite attitude and orbit control power from traditional toxic hydrazine to sustainable non-toxic propellant (Experimental Research and In-Orbit Verification of ADN-Based Liquid Space Engines, Yao Zhaopu, Zhang Wei, Wang Meng, Chen Jun, Shen Yan, Rocket Propulsion, 2018, 44(1), 8-14). At present, the developed ADN liquid propellant has been equipped in more than 20 national key satellite constellations such as Ningxia-1, Qilu-1, Yaogan 35 / 36 / 39, and has achieved significant economic and social benefits.

[0005] Whether it is the LMP-103S or FLP-106 ADN liquid propellant developed abroad, or the AMP-112-I ADN liquid propellant developed domestically, both use methanol or N-methylformamide as fuel and ADN as oxidant. Through the redox reaction between molecules, high-temperature and high-pressure nitrogen, carbon dioxide, water and other gases are produced to achieve the conversion of chemical energy to kinetic energy. However, the carbon content of methanol is as high as 37.49%, and the carbon content of N-methylformamide is as high as 40.67%. It is difficult to completely react with the oxygen element in ADN in the confined space of the engine (millisecond time and centimeter space) to achieve efficient combustion. The catalyst is prone to carbon deposition, covering the active center, resulting in the attenuation of the engine's working performance. At present, the pulse working times of ADN liquid propellants developed at home and abroad are all less than 200,000 times, which can only meet the requirements of small satellites to work in orbit for 5 years (Green space propulsion: Opportunities and prospects, Progress in Aerospace Sciences, 2014, 71, 128-149; Research on key components test and ignition performance of green high-performance ADN-based thrusters, Journal of Ordnance Equipment Engineering, 2017, 38 (12), 163-166). However, large satellites carrying more payloads, more powerful functions and more extensive uses usually require a working life of more than 10-15 years. The propellant must have a pulse working characteristic of more than 400,000 times, which is crucial for the establishment of a national space infrastructure system in orbit for a long time. Therefore, it is of great scientific significance and application value to develop an ADN liquid propellant that can work with hundreds of thousands of pulses to meet the requirements of long-term life of large satellites in orbit. Summary of the invention

[0006] The present invention aims at the insufficient pulse working times of the current ADN liquid propellant and the defects of the prior art, by changing the traditional ADN liquid propellant formula and preparation method thereof (see Figure 6 ), introduce low-carbon nitrogen-rich ion salt to replace methanol as the fuel of the propellant, and provide an ADN liquid propellant that can work in pulses hundreds of thousands of times and its preparation method and application.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] A method for preparing a low-carbon and nitrogen-rich ammonium dinitramide liquid propellant, wherein the preparation method improves the energy density of the ADN liquid propellant while reducing the carbon content of the propellant by designing a low-carbon and nitrogen-rich ion salt, thereby improving the redox reaction at the molecular level, substantially eliminating the carbon deposition of the catalyst, and achieving hundreds of thousands of pulse operations of the propellant. The specific preparation method comprises the following steps:

[0009] The first step is to add ammonium dinitramide and water into a reactor and stir at room temperature for half an hour to obtain an ammonium dinitramide aqueous solution;

[0010] In the second step, low-carbon nitrogen-rich ion salts are slowly added to the ammonium dinitramide aqueous solution in batches to obtain a mixed solution. After the addition is completed, the temperature is raised to 50°C-70°C, stirring is continued, and activation is performed for 1-2 hours until the system is completely dissolved into a transparent liquid, thereby obtaining a low-carbon nitrogen-rich ammonium dinitramide liquid propellant.

[0011] Furthermore, in the second step mixed solution, the mass fraction of ammonium dinitramide is 35-70%, the mass fraction of water is 10-30%, and the mass fraction of nitrogen-rich ion salt is 10-40%. The sum of the three is 100%, which constitutes the propellant formula.

[0012] Furthermore, in the second step, the low-carbon nitrogen-rich ion salt is one of carbohydrazide dinitrate, dinitramide dimethylamine, guanidine nitrate, 5-aminotetrazolyl nitrate, 5-aminotetrazolyl guanidine salt, and 5-aminotetrazolyl hydrazine salt, preferably carbohydrazide dinitrate.

[0013] The low-carbon nitrogen-rich ADN liquid propellant of the present invention can improve the pulse working times, process performance and combustion efficiency of existing propellants. The low-carbon nitrogen-rich ADN liquid propellant of the present invention can carry out self-sustaining combustion in the engine in the presence of a catalyst or other ignition agent to generate high-temperature and high-pressure gas, which is ejected from the thruster nozzle, that is, thrust is generated in the opposite direction to achieve aircraft attitude and orbit control.

[0014] A low-carbon and nitrogen-rich ammonium dinitramide liquid propellant is prepared by the method, and its formula and mass fraction ratio are: 35-70% ammonium dinitramide, 10-40% low-carbon and nitrogen-rich compounds, and 10-30% water.

[0015] The invention discloses an application of a low-carbon and nitrogen-rich ammonium dinitramide liquid propellant. The low-carbon and nitrogen-rich ADN liquid propellant can be used as fuel for satellites, spacecraft, and rockets, meeting the urgent needs of various aircraft for non-toxic and high-energy advanced space propulsion. Specifically, the propellant can achieve 420,000 pulse ignition operations under 300°C preheating conditions, and is particularly suitable for attitude and orbit control systems of large satellites, meeting the requirements for long-term on-orbit service life of spacecraft.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] (1) The propellant of the present invention uses low-carbon nitrogen-rich ion salt as a fuel to replace solvents such as methanol and N-methylformamide with high carbon content, and ADN as an oxidant to obtain a new ADN liquid propellant that can work in pulses for a long life, and the number of pulse operations can reach 420,000 times.

[0018] (2) The present invention uses low-carbon nitrogen-rich ion salt as fuel, which has a high energy density and combustion calorific value, and partially converts the traditional intermolecular redox reaction of ADN with methanol and N-methylformamide into an intramolecular redox reaction, which effectively weakens the reduction in the number of active centers on the catalyst surface caused by carbon deposition, and improves the long-life pulse working ability of the propellant.

[0019] (3) The raw material sources of the present invention are abundant, the preparation process is simple, and it is suitable for industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Example 5: 200th start-up 0.1s / 0.4s×100 pulse working curve;

[0021] Figure 2 Example 5 600th start 0.1s / 0.4s×100 pulse working curve;

[0022] Figure 3 Example 5: 1200th start-up 0.1s / 1s×100 pulse working curve;

[0023] Figure 4 Example 5: 2400th start-up 0.1s / 1s×100 pulse working curve;

[0024] Figure 5 Example 5: 4200th start-up 0.1s / 1s×100 pulse working curve;

[0025] Figure 6 The figure is a comparison diagram of propellant formulation design schemes, wherein (a) is a traditional ADN liquid propellant, and (b) is the ADN liquid propellant of the present invention. DETAILED DESCRIPTION

[0026] The present invention is further described below in conjunction with specific implementation cases.

[0027] The present invention uses the TEST (Toxicity Estimation Software Tool) toxicity calculation software developed by the United States Environmental Protection Agency (USEPA) to analyze the toxicity of the following low-carbon nitrogen-rich compound fuels (Table 1). The results show that the LD 50 The toxicity (median lethal dose) is between 620-1802 mg / kg, which is much lower than anhydrous hydrazine 59 mg / kg, methyl hydrazine 32.5 mg / kg, and unsymmetrical dimethyl hydrazine 122 mg / kg. It is an excellent green and non-toxic propellant fuel.

[0028] Table 1 The structure, carbon content, standard molar enthalpy of formation and toxicity of the compounds of the present invention

[0029]

[0030] Example 1-25 Preparation and ignition test of low-carbon nitrogen-rich ADN liquid propellant.

[0031] The oxidizer ADN is dissolved in water to form a uniform solution, and the nitrogen-rich low-carbon ion salt is slowly added to the ADN aqueous solution in batches, and the temperature is raised to 50°C, and stirring is continued. The system is activated for 1 hour until it is completely dissolved into a transparent liquid to obtain a low-carbon nitrogen-rich ADN liquid propellant. The propellant density is obtained by digital density meter DMA 4500M analysis (room temperature); the propellant specific impulse and combustion chamber temperature and other data are calculated by NASA-CEA software. The initial assumptions for the calculation are: the combustion chamber pressure is set to 1.5MPa, and the expansion ratio is 60:1. The specific content and results of each component are shown in Table 2 below.

[0032] The ADN green liquid propellant start-up ignition test test procedure is as follows: low-carbon nitrogen-rich ADN liquid propellant is loaded into a tank, and under the control of a solenoid valve, high-pressure nitrogen squeezes the propellant into a catalytic bed (preheated to 300° C. in advance) to directly cause a catalytic decomposition reaction, and the procedure is performed at 0.1s (on) / 0.4s (off)×100 times or 0.1s (on) / 1s (off)×100 times. By measuring the engine combustion chamber pressure (Pc) and temperature (T), the pulse working performance of the low-carbon nitrogen-rich ADN green liquid propellant formulation system prepared in Examples 1-25 is analyzed, and data comparison analysis is performed with Comparative Examples 1-2 (Table 3).

[0033] Table 2 Low carbon nitrogen rich ADN liquid propellant formula and its properties

[0034]

[0035] Table 3 ADN liquid propellant formula and performance comparison published in literature

[0036]

[0037] From the data analysis in Table 2, it can be seen that after the low-carbon nitrogen-rich substances used in the present invention replace methanol, they can form a uniform and stable solution system with ADN, and the density-specific impulse performance is improved to a certain extent. Due to the high positive formation enthalpy of 5-aminotetrazolyl guanidine salt and 5-aminotetrazolyl hydrazine salt, under the same mass, the specific impulse of the ADN liquid propellant formula formed reaches 266s and 273s (Table 2, Example 18 and Example 25), respectively, which is much higher than the 253s of the LMP-103S type ADN liquid propellant reported abroad. Under the same conditions, although the specific impulse of the carbohydrazine dinitrate system is 230s (Table 2, Example 5), by appropriately adjusting the carbohydrazine dinitrate content to 40%, the ADN liquid propellant specific impulse can reach up to 275s (Table 2, Example 3), which is much higher than the 253s of the methanol system. The low-carbon nitrogen-rich compounds of the present invention also improve the energy density of the ADN liquid propellant to a certain extent. High energy density can effectively reduce the volume of satellite tanks and lighten the structural weight of satellites, thereby carrying more payloads and reducing launch costs.

[0038] Compared with the 60,000 pulse working life of LMP-103S ADN liquid propellant reported by Sweden (Table 3, Comparative Example 2), the pulse ignition performance of the propellant is greatly improved after the low-carbon nitrogen-rich ion salt carbohydrazide dinitrate is used to replace methanol, as shown in Table 3. Figure 1-Figure 5 , reaching 420,000 times, and the combustion pressure and combustion temperature during the propellant ignition process are stable, which is 7 times the results reported abroad (Table 3, Example 5), basically meeting the mission requirements of large satellites working on orbit for more than 10 years. The pulse working times of the ADN liquid propellant using 5-aminotetrazolyl guanidine salt can also reach 320,000 times (Table 3, Example 18), exceeding the result of 200,000 times of the pulse working times of the AMP-112-I type ADN liquid propellant currently used in my country (Table 3, Comparative Example 1). Although the pulse working times of the ADN liquid propellant of 5-aminotetrazolyl hydrazine salt have been reduced to 260,000 times (Table 3, Example 25), the theoretical specific impulse performance has been greatly improved to 273s. The present invention is the first to introduce low-carbon nitrogen-rich ion salts into the ADN liquid propellant system for direct use as fuel, which greatly reduces the carbon content of the ADN liquid propellant, partially converts the traditional redox reaction between ADN and methanol molecules into an intramolecular redox reaction, effectively weakens the reduction in the number of active centers caused by carbon deposition on the catalyst surface, improves the long-life pulse working ability of the propellant, and also improves the energy density of the ADN liquid propellant to a certain extent.

[0039] The carbon content of low-carbon nitrogen-rich ion salts such as carbohydrazide dinitrate, dinitramide dimethylamine, 5-aminotetrazolylguanidine salt, and 5-aminotetrazolylhydrazine salt is between 5.56% and 16.67%, which is much lower than 37.49% of methanol and 40.67% of N-methylformamide. At the same time, these substances have higher formation enthalpy and energy density. The present invention uses low-carbon nitrogen-rich ion salts as a fuel to replace methanol to form a new ADN green liquid propellant system, solve the problem of catalyst carbon deposition poisoning caused by high carbon content of the propellant, and achieve a pulse working frequency of 420,000 times, meeting the mission requirements of satellites working in orbit for more than 10 years. The present invention solves the defect that the pulse working frequency of existing ADN liquid propellants is less than 200,000 times, and has significant technical progress and beneficial effects.

[0040] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A low-carbon and nitrogen-rich ammonium dinitramide liquid propellant, characterized in that: The low-carbon nitrogen-rich ammonium dinitramide liquid propellant is composed of ammonium dinitramide, low-carbon nitrogen-rich ion salt, and water, wherein the mass fraction of each component is: 35-70% ammonium dinitramide, 10-40% low-carbon nitrogen-rich ion salt, 10-30% water, and the sum of the three is 100%; The low-carbon nitrogen-rich ion salt is one of carbohydrazide dinitrate, dinitramide dimethylamine, guanidine nitrate, 5-aminotetrazolyl nitrate, 5-aminotetrazolyl guanidine salt, and 5-aminotetrazolyl hydrazine salt.

2. A low-carbon and nitrogen-rich ammonium dinitramide liquid propellant according to claim 1, characterized in that: The low-carbon nitrogen-rich ion salt is carbohydrazide dinitrate.

3. A method for preparing the low-carbon and nitrogen-rich ammonium dinitramide liquid propellant according to claim 1 or 2, characterized in that: The preparation method The following steps are involved: The first step is to mix ammonium dinitramide and water, and stir at room temperature for half an hour to obtain an ammonium dinitramide aqueous solution; The second step is to slowly add low-carbon nitrogen-rich ion salts to the ammonium dinitramide aqueous solution in batches. After the addition is completed, the temperature is raised to 50°C-70°C, and stirring is continued. The activation is performed for 1-2 hours until the system is completely dissolved into a transparent liquid to obtain a low-carbon nitrogen-rich ammonium dinitramide liquid propellant.

4. An application of the low-carbon and nitrogen-rich ammonium dinitramide liquid propellant according to claim 1 or 2, characterized in that: The low-carbon and nitrogen-rich ammonium dinitramide liquid propellant is used as fuel for various aircraft.

5. The use of a low-carbon and nitrogen-rich ammonium dinitramide liquid propellant according to claim 4, characterized in that: Under the condition of preheating at 300° C., the propellant can achieve pulse ignition operation 420,000 times, is suitable for attitude and orbit control systems of large satellites, and meets the requirements for the long-term on-orbit service life of spacecraft.

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