共查询到20条相似文献,搜索用时 31 毫秒
1.
ABSTRACT The quantities of olefins, polyaromatic hydrocarbons and char formed during thermal decomposition in closed systems of alkylbenzenes are substantially reduced if the decomposition takes place in the presence of a good acceptor molecule such as pyrene or adamantane. The chemistry seems to be applicable to the upgrading of whole crude oils by a thermal treatment at 425-450°C in a closed system for 20-25 minutes. 相似文献
2.
ZDDP热稳定性及其对抗磨性能的影响 总被引:2,自引:0,他引:2
使用热重法(TGA)和红外法(FTIR)研究了不同ZDDP的热稳定性能,Prim.ZDDP热稳定性能最好,其后依次为Sec.ZDDP-4,Sec.ZDDP-3,Mixed ZDDP,Sec.ZDDP-2,Sec.ZDDP-1。不同添加剂对ZDDP分解也有一定影响,其中清净剂能延缓ZDDP的分解;抗氧剂在短时间内表现不明显,氧化8 h则也能在一定程度上延缓ZDDP的分解;分散剂与抗氧剂效果相似,且同时能把分解的物质分散于油品中,在整个氧化过程中保持油品透明无沉淀。在单剂抗磨性能方面,表现最好的为Prim.ZDDP,Mixed ZDDP与Prim.ZDDP相差不大,其次为Sec.ZDDP-3,Sec.ZDDP-1/Sec.ZDDP-2,Sec.ZDDP-4。油品氧化后,其抗磨性能出现一个先升后降的过程,不同的ZDDP分解速率不一样,导致其在氧化不同时间后抗磨性能出现分化,表现最好的为Prim.ZDDP。 相似文献
3.
氨基甲酸酯热分解法制备对氯苯基异氰酸酯 总被引:1,自引:1,他引:0
对氨基甲酸酯热分解法制备对氯苯基异氰酸酯(4CPI)的工艺进行了研究。以对氯苯胺和碳酸二甲酯为原料,合成了热分解前体对氯苯基氨基甲酸甲酯(M4CPC);通过核磁共振氢谱、傅里叶变换红外光谱和热重分析对M4CPC的结构和性能进行了表征,确定了适宜的M4CPC热分解温度为150~200℃。常压下对M4CPC热分解溶剂的考察结果表明,高介电常数的有机溶剂对M4CPC的分解比较有利。M4CPC热分解制备4CPI的主要副产物为N,N′-双(4-氯苯基)脲。以低毒的N,N′-二甲基乙酰胺为溶剂,在M4CPC的摩尔分数为10%、催化剂用量为m(Bi2O3)∶m(M4CPC)=0.05、反应温度162~164℃、反应时间1h的优化条件下,M4CPC的转化率为90.4%,4CPI的选择性为66.0%。 相似文献
4.
5.
辽河油田杜84块超稠油由蒸汽吞吐转为蒸汽辅助重力泄油(SAGD)开发后,产生了较高浓度的H2S,导致脱硫设施投入和油气处理成本增加。通过原油、伴生气、地层水和储层矿物地球化学测试分析,H2S产量与原油含硫量、地层水SO42-浓度无明显相关性,而与储层中黄铁矿含量一致性强,黄铁矿中的硫属于生物来源,同位素范围与原油基本一致,起源于原油稠化阶段,大量形成于稠油热采阶段。高温高压热模拟实验表明,注蒸汽热力采油过程中,除含硫有机质热裂解(TDS)和硫酸盐热化学还原反应(TSR)外,黄铁矿氧化分解也是H2S形成途径之一,当注入低矿化度蒸汽对地层水稀释后,SO42-浓度下降,黄铁矿分解是H2S的主要生成途径,H2S的生成和分布受控于油藏地质条件、开发方式、开发时间和受热温度。 相似文献
6.
7.
ABSTRACTAn accurate thermal decomposition model of Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX)-based polymer-bonded explosives is indispensable to the design of countermeasure against environmental thermal stimuli for certain explosive devices. However, the complicated chemical reactions occurring in decomposition of HMX-based polymer-bonded explosives pose great challenge to scientists. In this study, the thermal ignition kinetic model proposed by Tarver is implemented to study thermal decomposition of HMX-based polymer-bonded explosives using commercial software Abaqus, which does not only consider the thermal decomposition of HMX but also the polymer binders. The simulation results are compared to ODTX and Scaled Thermal Explosion Experiment (STEX) and reasonably good agreements are achieved. Then the thermal decomposition model is applied to analyze an explosive device exposed to environmental thermal stimuli. Furthermore, countermeasure against environmental thermal stimuli is suggested and analyzed quantitatively for the explosive device. The time to explosion and environmental temperature before ignition is calculated and analyzed for the explosive device under various heating rates. 相似文献
8.
9.
采用高压釜热解法研究了硫醚类硫化物的热解规律。研究表明:硫醚类硫化物的热解产物主要是硫化氢和元素硫,结构不同的硫醚分解温度和分解产物也不同,具体的反应过程取决于自身的分子结构和反应条件。同时采用金属粉末腐蚀法研究了硫醚类硫化物的腐蚀性,结果表明硫醚腐蚀性是由于自身在高温条件下发生热解生成腐蚀性很强的"活性硫"造成的。 相似文献
10.
天然气水合物注热开采数学模型 总被引:4,自引:2,他引:4
根据热力学第一定律及天然气水合物分解机理,在合理假设基础上,建立了包括物质守恒方程、能量守恒方程、分解动力学方程及辅助方程的天然气水合物注热开采数学模型。对数学模型进行差分处理得到差分方程组,采用隐式求解压力、显式求解饱和度(IMPES)的方法,考虑天然气水合物分解的压力、温度平衡条件,对模型进行求解,据此编制了数值模拟器。数值模拟器很好地拟合了注热开采实验的产气速率和温度分布,验证了数学模型的有效性。数值模拟及注热开采实验分析表明,天然气水合物注热开采可分为自由气释放、水合物分解及边界效应3个阶段,水合物分解存在分解前缘,注入端一侧水合物大部分已经分解,出口端一侧水合物分解较少,饱和度较高。图5表1参11 相似文献
11.
Tomoki Naya 《Journal of Energetic Materials》2013,31(2):73-90
Ammonium nitrate (AN) has attracted much attention due to its clean burning nature as an oxidizer. However, an AN-based composite propellant has the disadvantages of low burning rate and poor ignitability. In this study, we added nitramine of cyclotrimethylene trinitramine (RDX) or cyclotetramethylene tetranitramine (HMX) as a high-energy material to AN propellants to overcome these disadvantages. The thermal decomposition and burning rate characteristics of the prepared propellants were examined as the ratio of AN and nitramine was varied. In the thermal decomposition process, AN/RDX propellants showed unique mass loss peaks in the lower temperature range that were not observed for AN or RDX propellants alone. AN and RDX decomposed continuously as an almost single oxidizer in the AN/RDX propellant. In contrast, AN/HMX propellants exhibited thermal decomposition characteristics similar to those of AN and HMX, which decomposed almost separately in the thermal decomposition of the AN/HMX propellant. The ignitability was improved and the burning rate increased by the addition of nitramine for both AN/RDX and AN/HMX propellants. The increased burning rates of AN/RDX propellants were greater than those of AN/HMX. The difference in the thermal decomposition and burning characteristics was caused by the interaction between AN and RDX. 相似文献
12.
13.
Abstract This article presents a study of the effects of damage on the thermal decomposition, combustion and deflagration-to-detonation transition (DDT) of the NEPE (Nitrate Ester Plasticized Polyether) propellant in order to assess its safety. The study includes: (1) to induce damage into the propellants by means of a large-scale drop-weight apparatus; (2) to observe microstructural variations of the propellant with a scanning electron microscope (SEM); (3) to investigate thermal decomposition tests; (4) to carry out closed-bomb tests and (5) to perform DDT tests. The NEPE propellant is found to be a viscoelastic material. The matrices of damaged samples are severely degraded, but the particles are not. The results of the thermal decomposition tests, closed-bomb tests and DDT tests show that the microstructural damage in the propellant has some marked effects on its thermal decomposition rate, bum rate and transition rate from deflagration to detonation. It is shown that the impact damage strongly influences on safety properties of the NEPE propellant. 相似文献
14.
This work refers to a study of the thermal decomposition of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) by differential scanning calorimetry (DSC) under nonisothermal conditions, with heating rates from 5 to 20°C min?1. The influence of the particle size in the thermal decomposition of HMX was verified. The activation energy for the decomposition of each sample was calculated using the peak temperature shift methods, proposed by Kissinger and Ozawa. A significant variation in the results was observed according to the range of the particle size used. The results showed that, as the particle size of HMX increased, the thermal decomposition temperature of HMX and the decompositional activation energies ranges enhanced. At the same time, at a constant heating rate, the decomposition temperatures of the smaller particles were lower than those of larger ones. The critical temperature for thermal explosion of each sample was calculated. Also, the values of ΔS#, ΔH#, and ΔG# of reaction for each particle size were computed. 相似文献
15.
Sophie Ringuette Robert Stowe Gérard Charlet Queenie Kwok David E.G. Jones 《Journal of Energetic Materials》2013,31(4):307-320
The knowledge of the degradation mechanisms of propellants is a key factor in understanding some performance issues of chemical propulsion systems. The thermal decomposition of GAP and a deuterated analog was studied. Thermogravimetric analyses coupled to differential thermal analysis, Fourier transform infrared spectrometry, and mass spectrometry were employed to evaluate the complete decomposition profile of GAPs. Evidence of labeled gaseous compounds were found both in mass spectra and in the FTIR spectra, where new frequencies associated with isotopic labeled gaseous products were detected. An imine-bearing species was detected among the decomposition products, apparently originating from the breakdown of the azide group. 相似文献
16.
有机热载体广泛应用于多个行业的加热系统。热稳定性是其最重要的性能指标,能够反映油品在高温下发生分解及聚合的倾向。以DIN 51528-1998《未使用过的热传导液热稳定性测定法》作为参考标准,对SH/T 0680-1999《热传导液热稳定性测定法》进行修订,建立GB/T 23800-2009《有机热载体热稳定性测定法》,该标准要求使用毛细管色谱柱、报告终馏点为538 ℃以前的馏分沸程结果、保证仪器温度均匀分布、试验时间不少于720 h。修订后的标准方法能够更加准确反映不同类型有机热载体在不同温度和加热时间下的热稳定性能。 相似文献
17.
An integrated technique has been developed for the study of the thermal chemistry of petroleum fractions—particularly the asphaltenes. The procedure involves the integrated use of a pyroprobe/gas chroma-tographic/mass spectrometric technique which offers information about the structuraI-types and distribution within the volatile products from the thermal decomposition of asphaltenes. The technique offers itself as an attractive on-line analytical method for the study of structural types that occur in asphaltenes as well as a technique for studying the parameters that can influence asphaltene decomposition. The concept of deducing “average” structures of asphaltenes is briefly discussed in terms of the observance of the lower molecular weight species in the volatile products of the thermal decomposition. 相似文献
18.
Abstract The effect of ‘p’ type rare earth oxides with partially filled ‘f’ orbitals like La2O3, Pr2O3 and Nd2O3 on the thermal decomposition of ammonium perchlorate (AP) has been studied using isothermal and non-isothermal methods of thermal analysis. Differential thermal analysis (DTA) and thermogravimetry (TG) results reveal that these oxides influence the thermal decomposition pattern of AP significantly and bring down the decomposition temperature substantially. Isothermal studies showed substantial acceleration of the decomposition of AP with the incorporation of these oxides as little as 0.05%. Isothermal data were analyzed using various kinetic models. The activation energy for the catalyzed decomposition of AP was significantly lower. The catalytic effect is explained on the basis wherein the ‘p’ type oxides act as conduites through metal cation in the electron-transfer mechanism for AP decomposition. 相似文献
19.
从理论和生产经验方面分析了造成LDPE装置反应器内热分解的原因,并对管式法LDPE装置如何防止反应器内热分解事故提出相应的对策。 相似文献
20.
ABSTRACT An integrated technique has been developed for the study of the thermal chemistry of petroleum fractions—particularly the asphaltenes. The procedure involves the integrated use of a pyroprobe/gas chroma-tographic/mass spectrometric technique which offers information about the structuraI-types and distribution within the volatile products from the thermal decomposition of asphaltenes. The technique offers itself as an attractive on-line analytical method for the study of structural types that occur in asphaltenes as well as a technique for studying the parameters that can influence asphaltene decomposition. The concept of deducing “average” structures of asphaltenes is briefly discussed in terms of the observance of the lower molecular weight species in the volatile products of the thermal decomposition. 相似文献