5-氨基四氮唑类固体推进剂热解动力学及燃烧特性研究

发布时间：2018-08-08 11:31

【摘要】：固体推进式灭火技术(SPGG)凭借其诸多优异特性而获得了广泛的关注,诸如惰性气体生成量大、可常压贮存、可配合使用液体灭火剂、可按需求定量释放灭火剂等优点,SPGG已成为一种热门并极具前景的哈龙替代灭火技术。然而,SPGG灭火装置内部的主要成分5-氨基四氮唑/硝酸锶(5AT/Sr(N03)2)推进剂存在产气温度高、燃速受压力影响变化大等缺陷,削弱了 SPGG灭火装置的灭火效率,限制其推广和使用。因此,本文以高氮含能化合物5-氨基四氮唑及其与硝酸锶组成的推进剂为研究对象,通过添加正负催化剂的方式,深入研究粒径、催化剂等变量对5AT/Sr(N03)2推进剂燃烧性能的影响,从热解机理的角度揭示各变量对固体推进剂燃烧性能的影响作用机制,旨在探索一种燃温低、燃速快、燃速压力指数低的新型5AT/Sr(N03)2固体推进剂。首先,本文以高氮含能化合物5AT为研究对象,深入探究5AT的热解特性及热解反应机制。一方面,制备四种粒径的5AT样品,联合采用热重、热流技术对不同粒径的5AT样品的热稳定性进行对比分析,发现粒径越小的5AT对热的抵抗力越差,借助比表面积和扫描电镜等测试手段揭示粒径对5AT热解的影响机理,推测可能是由于小的颗粒粒径会形成较高的表面能、更快的传热传质速率所导致的,从四种粒径中选出较容易发生反应、且易实现操作的5AT粒径范围,同时预测5AT样品热解反应属于Di扩散模型;另一方面,研究三种不同的纳米过渡金属氧化物(纳米氧化铁、纳米氧化铜、纳米氧化镍)催化剂对5AT热分解的催化机理,借助热重、热流、傅里叶红外、质谱、比表面积测试、电镜扫描等测试手段,发现过渡金属氧化物的存在将会加速5AT的热解速率,这是由于过渡金属氧化物的添加阻碍了 CN的组合成键,而是加速了 CN键的断裂所造成的。总结来说,粒径更小、含有过渡金属氧化物的5AT热敏感性更强,在生产、运输、贮存的过程中也需更多安全方面的关注。其次,本文以5AT/Sr(NO3)2推进剂为研究对象,结合热重-质谱联用技术探究了推进剂的热解机理,研究发现5AT/Sr(NO3)2推进剂的热解共分为四个阶段,第一阶段是5AT分解生成叠氮酸、氨基氰和三聚氰胺:第二阶段是三聚氰胺分解产生氰化氢及蜜勒胺、蜜白胺等固态产物;第三阶段中蜜勒胺继续分解生成氨基氰、叠氮酸、氰化氢等,同时与尚未分解的硝酸锶之间发生了氧化还原反应生成甲醛、二氧化碳;第四阶段硝酸锶发生分解最终生成氧化锶和氮氧化物。最后,本文借助TG-DSC测试、燃温测试、燃速测试、导热系数测量、扫描电镜等测试手段,分别研究了负催化剂(20%碳酸钙冷却剂)、正催化剂(1%纳米氧化铁、1%纳米氧化铜、1%纳米氧化镍、2%微米氧化铁、2%纳米氧化铁)对5AT/Sr(NO3)2推进剂燃烧性能的调节作用。添加了 20%碳酸钙的推进剂在反应初期的热解温度和活化能均减小,燃速升高,这是由于碳酸钙调节了固相区的反应,增大了固相区的反应表面积所引起的,而在反应末期其热解温度和活化能均变大而燃速大幅度降低,这是由于碳酸钙分解产生的CO2引发了气相区反应的团聚效应造成的。可以看到尽管添加了碳酸钙之后,推进剂出现了麦撒效应并大大降低了燃烧温度,但是燃速同时大幅度降低,不利于SPGG灭火装置快速推出灭火介质。添加了过渡金属氧化物(TMO)的5AT/Sr(NO3)2推进剂燃速大大提高,同时燃温也有不同程度的降低,并且燃速、燃温改变幅度与TMO的导热系数大小规律保持一致。研究作用机理发现,TMO可以调节热量传递和反应的表面积以实现对固相区反应的控制,还可以改变气相区反应的吸热/放热量,实现协同控制固相区反应和气相区反应的作用。添加了 2%微米氧化铁的推进剂比添加了 2%纳米氧化铁的推进剂燃速更快,发现了纳米氧化铁分散在推进剂中所存在的团聚效应、颗粒覆盖效应,指出将纳米颗粒应用作燃速调节剂时应提前采用电化学溶解等手段进行表面改性处理。通过本文对5AT/Sr(NO3)2推进剂的研究,设计出一种安全、可扩展、成本低廉、性能优良的新型推进剂配方,实现了对传统5AT/Sr(NO3)2推进剂燃烧性能的优化,满足了在降低燃烧温度的同时提高燃速、降低燃速压力指数的要求,提高5AT/Sr(NO3)2推进剂在SPGG灭火装置中的灭火效率,进一步推动了新型SPGG灭火技术的市场应用和推广,促进哈龙替代灭火技术的发展。
[Abstract]:Solid propelled fire extinguishing technology (SPGG) has received extensive attention for its excellent characteristics, such as large amount of inert gas, storage at normal pressure, and the use of liquid fire extinguishing agent to release fire extinguishing agent according to demand. SPGG has become a hot and promising alternative fire extinguishing technology for Halon. However, SPGG fire extinguishing assembly The main components, 5- amino tetrazolium / strontium nitrate (5AT/Sr (N03) 2) propellant, have high gas production temperature and high burning rate affected by pressure, which weaken the fire extinguishing efficiency of the SPGG fire extinguisher and restrict its popularization and use. Therefore, the propellant composed of 5- amino tetrazolium and its strontium nitrate with high nitrogen energetic compound and the propellant composed of strontium nitrate are studied in this paper. The effect of particle size, catalyst and other variables on the combustion performance of 5AT/Sr (N03) 2 propellant was investigated by adding positive and negative catalysts. The effect mechanism of various variables on the combustion performance of solid propellants was revealed from the point of view of pyrolysis mechanism. A new type of 5AT/Sr (N03) with low combustion temperature, fast burning rate and low burning rate pressure index was explored. ) 2 solid propellant. First, in this paper, a high nitrogen energetic compound 5AT was used as the research object to explore the pyrolysis characteristics of 5AT and the mechanism of pyrolysis reaction. On the one hand, the 5AT samples of four kinds of particle sizes were prepared. The thermal stability of 5AT samples with different particle sizes was analyzed by thermogravimetry and heat flow technique, and the resistance of 5AT to heat was found with smaller particle size. The worse the force, the influence mechanism of particle size on 5AT pyrolysis is revealed by means of specific surface area and scanning electron microscope. It is presumed that it may be caused by the formation of higher surface energy and faster heat and mass transfer rate by the small particle size. It is possible to choose the 5AT particle size range easily and easily to be operated from four kinds of particle sizes. The pyrolysis of 5AT samples belongs to the Di diffusion model. On the other hand, the catalytic mechanism of three different nano transition metal oxides (nanoscale iron oxide, nano cuprous oxide, nanoscale oxide) catalyst for the thermal decomposition of 5AT is studied, and the transition from thermogravimetry, heat flow, Fourier infrared, mass spectrum, specific surface area test and electron microscope scanning are found. The presence of metal oxides will accelerate the pyrolysis rate of 5AT because the addition of transition metal oxides hinders the combination of CN, but accelerates the fracture of the CN bond. In summary, the particle size is smaller, and the 5AT with transition metal oxide is more sensitive, and more safety is needed in the process of production, transportation and storage. Secondly, using 5AT/Sr (NO3) 2 propellant as the research object, the pyrolysis mechanism of propellant was investigated by TG mass spectrometry combined with TG mass spectrometry. The pyrolysis of 5AT/Sr (NO3) 2 propellants was divided into four stages. The first phase was 5AT decomposition of azido, cyanamide and melamine: the second stage was melamine decomposition production. Hydrogen cyanide and melalamines, melamine and other solid products; the third stage melalamines continue to decompose cyanide, azido, hydrogen cyanide and so on. At the same time, the oxidation-reduction reaction of the unresolved strontium nitrate is formed to produce formaldehyde and carbon dioxide; the fourth stage of strontium nitrate decomposition finally produces strontium oxide and nitrogen oxide. Finally, this is the result of the formation of strontium oxide and nitrogen oxide. With the help of TG-DSC test, combustion temperature test, burning rate test, thermal conductivity measurement, scanning electron microscope and other testing means, the combustion performance of 5AT/Sr (NO3) 2 propellant is regulated by negative catalyst (20% calcium carbonate coolant), positive catalyst (1% nanometer iron oxide, 1% nano copper oxide, 1% nano nickel oxide, 2% micron iron oxide, 2% nanometer iron oxide). The pyrolysis temperature and activation energy of the propellant with 20% calcium carbonate were reduced and the burning rate increased. This is due to the effect of calcium carbonate on the reaction of the solid state and the increase of the surface area of the solid state, while the pyrolysis temperature and activation energy of the solid state are all larger and the burning rate is greatly reduced at the end of the reaction, which is due to the carbonation. The CO2 produced by calcium decomposition causes the agglomeration effect of the gas phase reaction. It can be seen that, after adding calcium carbonate, the propellant appears the mesa effect and greatly reduces the combustion temperature, but the burning rate decreases greatly at the same time, which is not conducive to the rapid release of the fire extinguishing medium by the SPGG extinguisher. The 5AT of the transition metal oxide (TMO) is added. The burning rate of /Sr (NO3) 2 propellant is greatly increased and the combustion temperature is reduced in varying degrees, and the burning rate is consistent with the law of the thermal conductivity of TMO. It is found that TMO can adjust the surface area of heat transfer and reaction to control the reaction of the solid phase region, and can also change the reaction of the gas phase region. Heat absorption / heat discharge is used to control solid state reaction and gas phase reaction in synergistic control. The propellant added with 2% micron iron oxide is faster than the propellant adding 2% nanometer iron oxide. The agglomeration effect of nano iron oxide dispersed in the propellant, the effect of particle covering, and the application of nano particles to the burning rate are found. Through the study of 5AT/Sr (NO3) 2 propellant, a new propellant formula with safety, expansibility, low cost and excellent performance has been designed through the study of 5AT/Sr (NO3) propellant in this paper. The combustion performance of the traditional 5AT/Sr (NO3) 2 propellant is optimized and the combustion temperature is reduced. At the same time, improving the burning rate and reducing the burning rate pressure index, improving the fire extinguishing efficiency of 5AT/Sr (NO3) 2 propellant in SPGG fire extinguishing device, further promoting the market application and popularization of new SPGG fire extinguishing technology, and promoting the development of Halon alternative fire extinguishing technology.
【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：V512

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