红外和热分析联用在化工产品研究中的应用

运用实例论述了红外光谱分析与热分析联用在化工产品的产品开发和检测方面的应用。     

ACCURACY OF LAKE AND STREAM TEMPERATURES ESTIMATED FROM THERMAL INFRARED IMAGES1

Emitted thermal infrared radiation (TIR, λ= 8 to 14 μm) can be used to measure surface water temperatures (top approximately 100 μm). This study evaluates the accuracy of stream (50 to 500 m wide) and lake (300 to 5,000 m wide) radiant temperatures (15 to 22°C) derived from airborne (MASTER, 5 to 15 m) and satellite (ASTER 90 m, Landsat ETM+ 60 m) TIR images. Applied atmospheric compensations changed water temperatures by ?0.2 to +2.0°C. Atmospheric compensation depended primarily on atmospheric water vapor and temperature, sensor viewing geometry, and water temperature. Agreement between multiple TIR bands (MASTER ‐ 10 bands, ASTER ‐ 5 bands) provided an independent check on recovered temperatures. Compensations improved agreement between image and in situ surface temperatures (from 2.0 to 1.1°C average deviation); however, compensations did not improve agreement between river image temperatures and loggers installed at the stream bed (from 0.6 to 1.6°C average deviation). Analysis of field temperatures suggests that vertical thermal stratification may have caused a systematic difference between instream gage temperatures and corrected image temperatures. As a result, agreement between image temperatures and instream temperatures did not imply that accurate TIR temperatures were recovered. Based on these analyses, practical accuracies for corrected TIR lake and stream surface temperatures are around 1°C.     

Systems thinking in a gas explosion accident – lessons learned from Taiwan

On July 31, 2014, at around 23:57, several huge explosions occurred that lasted for 2 h in Kaohsiung City, Taiwan. As a result of a gas leak from a ruptured underground pipeline, the catastrophic incident destroyed more than 6 km of roads, killed 32 people, injured 321 people, and damaged 3259 buildings. Pipeline explosions have been reported as a repeatedly occurring problem, indicating that (1) complex systems are difficult to manage and control, and (2) humans are unable to effectively learn from experiences of accidents. Initial analyses results reveal that root causes of this incident were a combination of a series of complex chain reactions, which eventually led to propylene leakage and explosion. This is a systematic problem, which can hardly be investigated or analyzed by traditional research approaches. Based on the investigation reports and “systems thinking” method, this study develops causal loop diagrams for the Kaohsiung gas explosion to explore the root causes of the disaster. The research results indicate that (1) this pipeline explosion incident was the result of the chain reactions and was the output of a complex system; (2) the mental model of “production first” and “experience gap” were the root causes of the disaster; and (3) to achieve a higher safety standard, continuous education to improve the mental model of “safety first and safety over production” are essential. The findings of this study may contribute toward the improvement of the standard operating procedure for disaster management and preventing similar incidents in the future.     

不同环境体系下锂离子电池热失控特性实验研究

针对锂离子电池热失控引发的航空运输安全问题,自主设计并搭建锂离子电池热失控灾害演化及危险性分析实验平台。在敞开和密封环境体系下,对电加热触发荷电量(State of Charge,SOC)为0%、50%和100%的18650型锂离子电池热失控规律进行了实验研究。观察单体锂离子电池在敞开和密封体系中的热失控现象,并记录单体锂离子电池热失控时间、温度峰值及相应的温度变化。数据结果显示,相比敞开体系,密封体系有效的延缓了锂离子电池发生热失控的时间,并降低了锂离子热失控时释放的能量,为锂离子电池的航空运输安全性研究提供了理论依据和工程技术参考。     

Effects of particle thermal characteristics on flame microstructures during dust explosions of three long-chain monobasic alcohols in a half-closed chamber

To reveal clearly the effects of particle thermal characteristics on flame microstructures during organic dust explosions, three long-chain monobasic alcohols, solid at room temperature and similar in physical-chemical properties, were chosen to conduct experiments in a half-closed chamber. In the experiments, the dust materials were dispersed into the chamber by air to form dust clouds and the hybrids were ignited by an electrical spark. A high-speed optical schlieren system was used to record the flame propagation behaviors. A fine thermocouple and an ion current probe were respectively used to measure the flame temperature profile and the reaction behaviors of the combustion zone. Based on the experimental results, combustion behaviors and flame microstructures in dust clouds with different thermal characteristics were analyzed in detail. As a result, it was found that the dust flame surfaces were completely covered by cellular structures that significantly increased the flame frontal areas. Flame propagated more quickly and the number of the cellular cells increased as increasing the volatility of the particles. On the contrary, maximum temperature and the thickness of the preheated zone decreased as increasing the volatility of the particles. According to the ion current profile, the particles in the preheat zone were pyrolyzed to intermediate radicals and the radicals' fraction in the higher volatile dust flame was higher than that in the lower volatile dust flame.     

A product analysis-based study on the mechanism of inflammable gas explosion suppression

To study the mechanism of the suppressing effect of Expanded Aluminium (EA) on the premixed gas explosion, premixed methane-air and propane-air gases were undergone explosion reaction in the presence of EA in a self-designed closed pipeline with the overpressures and the compositions, rates and sensitivities of products analyzed. The results showed that the 9.5% methane-air and 5% propane-air explosions produced peak pressures decreased by 79.3% and 65.6%, and residual methane and propane contents increased by 270% and 560% respectively than without EA. In addition, the results revealed that the explosions of propane in the presence of EA produced less methane and carbon oxides contents, but more ethylene and propylene contents. The simulation showed that H, O, and OH are the key factors affecting the rate of products. The product compositions, together with other parameters, suggested that EA decreased temperature, inhibited chain initiation and propagation reaction, but facilitated chain termination reaction by advancing and accelerating the gas phase and wall destruction reaction of radicals, especially collisions and concentration of key free radicals. This new research method based on the analysis of explosion products can be used for in-depth research into gas explosion features and shed light on the suppressing mechanism of EA in flammable gas explosion.     

受限空间内惰性气体对CH4爆炸抑制特性研究

N2和CO2是常用的惰性抑爆气体,为研究两种气体的抑爆特性,采用20L球形爆炸试验装置,分析了不同浓度配比条件下N2/CH4/空气以及CO2/CH4/空气混合气体的爆炸压力,同时采集爆炸后的气体样品,对比分析爆炸后残留气体的主要成分。结果显示:随CH4浓度从5%增加至12.5%时,完全抑制CH4爆炸需要的惰性气体最小量先增大后降低,CH4浓度在6.5%~7.5%之间时,抑爆需要的惰性气体的量最大;在同一CH4浓度条件下,抑爆需要N2的量大于CO2,并且CH4浓度在5%~6.5%时,抑爆需要两种惰性气体的量值差别最大;当CH4浓度一定时,随着加入惰性气体量的增大,爆炸最大超压逐渐降低,惰性气体浓度和爆炸超压之间基本呈线性关系;在同样条件下,相对于N2,CO2为抑爆气体时,爆炸后腔体内残留的CH4浓度较高。研究成果为惰性气体抑爆技术提供技术支撑,同时为揭示惰性气体抑爆机理有一定作用。     

氢安全研究现状及面临的挑战

氢能具有储运便捷、来源多样、洁净环保等突出优点,许多国家把发展氢能作为重要的能源战略。氢安全是氢能大规模商业化应用的重要保障。在分析国内外氢安全领域近年来最新研究进展的基础上,依次从氢泄漏与扩散、氢燃烧与爆炸、氢与金属材料相容性及氢风险评价等方面,系统总结了国内外氢安全研究面临的挑战,并对我国氢安全的发展提出了建议。     

Investigation of multiple domino scenarios caused by fragments

A model of multiple domino scenarios and the risk of the domino effect, which is a sequential chain escalating from the primary unit to the last unit, is presented in this paper. The trajectories of fragments from all units, the ground distribution of projectiles, and the risk of the sequential chain of the domino effect were calculated using Monte Carlo simulations. The results showed that the range affected by the fragments from each tank included the other tanks, meaning that fragments from one tank could hit the other tanks and cause multiple accidents, and that the sequential chain of the domino effect could indeed happen. The distributions of ground impacts showed that tank fragments were projected over long distances, up to 1200 m from the source. The spatial distribution of the kinetic energy at ground impact for tank fragments was also obtained. Moreover, the magnitudes of the probabilities of the primary, secondary, third, and fourth accidents in the domino chain were respectively about 10⁻⁷, 10⁻¹¹, 10⁻¹⁵, and 10⁻¹⁹. These results showed that for neighboring domino effect units in the same accident chain, the risk of the most recent domino effect was 10⁴ times that of the following domino effect.     

PLC控制系统在钢渣热焖工艺中的应用

利用PLC控制系统,实现在钢渣热焖工艺中的恒压供水和钢渣热焖定时定量喷水的自动控制要求,具有国际先进水平,取得了良好的经济效益、社会效益和环境效益.