Analyse der potentiellen Explosionswirkung von kurzzeitig in die Atmosphäre freigesetzten Brenngasmengen. Teil 2: Überprüfung der Modellgesetze anhand der Analyse von Schadensfällen

Analysis of the potential explosive effect of amounts of cßmbustible gases released into the atmosphere . Part 2: Testing of models on the basis of cases of damage. A theoretical model set up to estimate the strength of undampened atmospheric gas cloud explosions occurring after bursting of vessels has been secured by thorough analysis of constructional damage caused by three explosions involving vessel contents of up to 30 tonnes of hydrocarbons. The maximum peak pressure of the pressure wave at the edge of the cloud was found to be ca. 0.3 bar. Diagrams are presented which facilitate estimation of peak pressure and time of action of the deflagration pressure wave as function of the distance and the mass of gas released.     

The Critical Energy of Direct Initiation in Liquid Fuel‐Air and Liquid Fuel‐RDX Powder‐Air Mixtures in a Vertical Detonation Tube

Multiphase cloud detonation is an important but complex process, which has not been fully understood yet. Direct experimental data about the critical initiation energy (CIE) and pressure/velocity revolution of high explosive powder‐based multiphase cloud detonation is not available in the literature. In this paper, propylene oxide (PO), petroleum ether (PE), isopropyl nitrate (IPN), and a mixture of PE/IPN were individually dispersed to form a cloud in a 200 mm×5400 mm vertical detonation tube. Subsequently, this cloud was directly ignited by a high explosive. The critical initiation energy of various mist/air mixtures was measured by the up and down method. Meanwhile, the pressure history was recorded by six sensors along the detonation tube. RDX powder was added to the system and sprayed simultaneously with the liquid fuel to form a three‐phase gas‐liquid‐solid explosive cloud. The detonation pressure and velocity of all three‐phase cases significantly increased while the corresponding critical initiation energy decreased compared to the liquid‐air analogs. The CIE data were found to have a “U”‐shaped curve relationship to the fuel‐air ratio in two‐ and three‐phase systems, the minimum is always on the fuel‐rich side.     

无约束气云弱点火爆炸压力实验研究

引　言在可燃气体的输送、贮存、加工和使用过程中由可燃气体泄漏而形成的气云爆炸已给人类社会造成了巨大的人员伤亡和财产损失 ,近年来发生在我国的几起重大气云爆炸事故无不令人触目惊心 ,可见研究气云爆炸成灾模式及防治技术具有重要的社会和经济意义 .要防治可燃气云爆炸给社会造成的巨大灾难 ,首先就要掌握气云爆炸的强度 .关于可燃气云爆炸的研究可分为两大类 :一类是针对军事领域研究由炸药点燃气云从而形成爆轰波的过程[1,2 ] ;另一类是针对工业领域研究弱点火 (通常指点火能量小于10 0Ｊ)条件下的工业气云的爆炸过程[3～ 5] ,这正…     

Brände und Explosionen im Rahmen der Risikoermittlung

The procedure of assessing risks is treated by analyzing an event sequence following the puff release of gaseous propylene. The models for fireball, flash fire and explosion required for this purpose are presented. Their uncertainties and sensitivities are discussed and illustrated by numerical examples. Modeling and data uncertainties in assessing the probabilities of event sequences are characterized; their mathematical treatment is shown. Deterministic as well as probabilistic calculations are performed and their results are compared.     

降低间歇本体法PP装置丙烯单耗的工艺研究

分析了造成间歇本体法聚丙烯(PP)生产过程中丙烯单耗高的原因,提出了用变压吸附工艺回收不凝气,用连续氮气汽提置换闪蒸釜的工艺设想,初步研究和实践证明,采用连续汽提置换工艺可将闪蒸釜氮气置换过程排出的气体全部排入气柜回收处理,变压吸附工艺处理后的净化氮气中丙烯体积分数约1%,该技术预计可使间歇本体法PP装置每吨PP的丙烯...     

RDX基含铝炸药水中爆炸近场冲击波特性

通过水中爆炸试验,得到了RDX基含铝炸药在不同比例距离((-R))处的水中冲击波峰值压力、冲量和冲击波能.结果表明,在测试范围内,(-R)＜1.5 m/kg1/3,Al的质量分数为10%～20%时,冲击波峰值压力基本不变;(-R)≥1.5 m/kg1/3时,Al的质量分数为0～30%时,冲击波峰值压力基本不变.测试范围内,Al的质量分数为20%～30%时,冲量基本不变;Al的质量分数小于20%,冲量随Al含量的增加不断增大.(-R)＜1.0 m/kg1/3时,冲击波能随比例距离的增加而不断衰减;(-R)≥1.0 m/kg1/3时,冲击波能随比例距离的增加基本保持不变.(-R)=0.79 m/kg1/3(药柱18倍半径处)时,冲击波能量利用率只有25%左右,初始冲击波能损失了近1/2～3/5.     

Die mit Cäsiumphenolat katalysierte Addition von Propylenoxid an Monophenylmonopropylenglykol bei Drücken bis 1 000 at

The addition of propylene oxide to monophenyl monopropylene glycol in the presence of cesium phenolate as catalyst was investigated under pressure up to 1 000 at. Experiments carried out in substance have proved a first order in the catalyst, a pseudo zeroth order with respect to the epoxide and the hydroxyl component, respectively. The activation energy has been found to be 14.8 kcal/mole. The very high activation volume of ?55 cm³/mole rules out the possibility of an ionic mechanism under these conditions. The reaction takes place via a ternary transition state preceded by associates. The results with ¹⁴C-marked phenolate as well as paper chromatographic experiments show that there is no phenolate-glycolate transformation. The phenolate as catalyst maintains its original form in the course of the reaction.     

Verformungseigenschaften von Ölsaaten während des Abpreßvorganges

Deformation Characteristics of Oil Seeds during Pressing Process Up to now the deformation of compactable fixed beds made of natural meterial is described by the well-known press-equation. The specific quantities “proportion of radial to axial pressure” and the “coefficient of friction” are nearly unknown. By using rape seed of different condition, the deformation characteristic is going to be determined in a special test apparatus by taking up axial- and radial-pressure profils. Thus the proportions of radial to axial pressure and the coefficients of friction can be derived. The results are to be considered as a contribution to design gas sealing sections for continuous transport of seeds through pressure vessels. At the same time in order to facilitate comprehension of the events happening at same time order to facilitate comprehension of the events happening at solid/liquid separation by expression processes, the influence of the contents of seed oil under compressing by mechanical pressure is checked.     

Qualitätsmanagement bei der Herstellung von Chemieapparaten aus Sonderwerkstoffen

Quality Management during the Fabrication of Chemical Equipment Made of Special Materials Optimizing a material's resistance to corrosion by the addition of alloying elements up to their solubility limits will make it increasingly difficult to use these frequently unstable alloys for the manufacture of chemical plant. The requirements these materials have to meet in the manufacture of chemical plant in terms of manufacturing technology and quality management, are becoming increasingly stringent. The current situation, for example in the manufacture of domed heads of pressure vessels, forgings, heat exchangers, and filter screens with a high specific surface area as a constituent part of stirred suction filters using advanced metallic materials, is not very satisfactory. Results of fabrication tests necessary for pressure vessel manufacture as well as in-service failures frequently demonstrate insufficient expertise of workshops dealing with high-alloy stainless steels and nickel-based materials. That the in-service failure of compoents clearly leads to considerable costs due to maintenance, delays in supply, and production downtimes. The economic consequences can be substantial. The aim of this paper is to highlight sensitive areas by demonstrating the impact of unintentional and unnoticed fabrication-related changes in welding parameters and to provide information on easily applicable methods of monitoring techniques.     

TNT装药水中爆炸的数值模拟

采用AUTODYN软件对不同起爆方式下TNT装药水中爆炸模型进行了数值计算,并对计算结果进行了实验验证.根据计算结果分析了中心起爆、端面中心起爆和端面面起爆情况下,在装药不同方位的水中冲击波压力峰值随距离的变化趋势.计算结果表明,端面起爆状态下,装药径向的冲击波压力峰值均大于端部;中心起爆状态下,一定距离处,装药端面的压力峰值大于径向.改变起爆方式,可以实现水中爆炸冲击波能量的定向增益,提高特定方位爆炸能量利用率.     

Surface adsorption of propane, propylene and propane/propylene mixed gas on polyimide observed with X-ray and neutron reflectivity

We observed the surface adsorption layer of propylene, propane and propane/propylene mixed gas on a polyimide film as a function of pressure using X-ray (XR) and neutron (NR) reflectivity. It was initially confirmed by NR that the surface layer is an adsorption layer of propylene using deuterated gas. We have determined by XR the adsorption isotherms of these gases and found that the thickness of the surface adsorption layer of propane and propane/propylene mixed gas is much larger than that of propylene and the isotherm of propane/propylene mixed gas is similar to that of propane. The former and the latter findings predict that the affinity of propane to the polyimide is greater than propylene and the content of propane is much higher than that of propylene in the adsorption layer. We also evaluated the permeability coefficients of these gases as a function of the applied pressure, and found that the permeability coefficients begin to increase at a pressure corresponding to the onset of the adsorption layer. This suggests that the surface adsorption layer of the gas plays an important role in the hydrocarbon gas permeation mechanism in a polymer membrane, while a swelling of the polyimide film is the basis for the increase in the permeability with pressure.     

Theoretical and Experimental Studies on Blast Wave Propagation in Air

High pressure and temperature are produced when high explosives are detonated in open air. The heat of detonation of the explosive compound, peak pressure, and temperature of the blast wave are important blast parameters. A blast wave generated due to explosion propagates into the air medium at supersonic speed until the pressure in the blast zone is released completely. The intensity of the impact by the blast wave on any intervening solid object depends on the blast parameters and the speed of propagation of the blast wave. A theoretical analysis is carried out to predict the pressure produced in the expanding blast zone as function of distance and time by analytically solving the governing equations. The initial peak pressure and temperature of blast wave, which are required in the theoretical analysis, were calculated making use of the blast wave theory. For comparison, experiments were conducted by detonating different weights of high explosives, and pressures were recorded at various distances from the blast point. The high explosives used in the experiments were TNT (0.045, 0.5, 1, 15, and 40 kg) and Composition B (0.045, 0.5, 1, and 15 kg). The theoretical results are validated by comparison with the experimental data and empirical equations available in literature.     

Vergleichende Untersuchung der Festigkeitsberechnung von Druckbehältern unterschiedlicher Bauart

Comparative study of stress analysis for pressure vessels of various constructions . The present article is intended to demonstrate the need for constant comparison of design, strength, and production aspects in the construction of modern high pressure equipment. The various constructions of pressure vessels should be compared with regard to: the diameter ratios and resulting weight savings at otherwise identical operating pressure, internal diameter, and strength; boundary curves, showing the economically still justifiable diameter ratio for a given operating pressure and strength; limiting values and fields of application in which construction and transport problems also require consideration.     

水下爆炸冲击波传播的近似计算

水下爆炸冲击波传播计算由能流密度一时间曲线经验表达式化简。用简单数值积分法解由拉格朗日形式流体动力学方程、Hugoniot方程和能流密度一时间关系式组成的偏微分方程组,不同距离处的冲击波峰值由单点初始数据计算。结果表明,由近似计算方法所得结果与实测数据和相似律结果一致。适当选取起算参数,在5倍装药半径以外的爆炸远场范围计算精度良好。5倍装药半径以内的爆炸近场,冲击波未充分形成,计算方法失效。计算了几种含铝炸药的冲击波传播,表明冲击波能显著影响冲击波传播特性,冲击波能有利于抑制超压衰减。     

Werkstoff- und Schweißfragen bei der Herstellung von dickwandigen Druckbehältern für höhere Betriebstemperaturen aus Stählen mit 2 bis 3% Chrom und ca. 1% Molybdän

Materials and welding in the production of thick-walled pressure vessels for elevated operating temperature made of steels containing 2 to 3% of chromium and ca. 1% of molybdenum . High-temperature steels containing 2 to 3% of chromium and ca. 1% of molybdenum are resistant to hydrogen under pressure at temperatures up to about 500°C. Being readily weldable, they are excellently suited for high pressure equipment in chemical plant construction. Their tendency to embrittlement at operating temperatures of 400 to 500°C is a drawback. However, specific metallurgical measures adopted during the production of the semifinished material and the welding materials, and use of optimized welding techniques and heat treatment keep this embrittlement within limits. The article reports recent experiences gained in producing pressure vessels with welding seam thicknesses of up to 230 mm at the authors company.     

Role of particle collisions in shock wave interaction with a dense spherical layer of a gas suspension

The problem of interaction of an expanding spherical shock wave with a layer of particles is considered within the framework of the model of mechanics of continuous media with due allowance for granular pressure in the dense gas suspension. The influence of particle collisions on the shock wave expansion process is analyzed. Generation of collisional pressure and formation of shock wave structures in the gas suspension are found to be the governing factors of motion of the cloud of particles at the initial stage.     

Entwicklung und Erprobung eines Wäschersystems zur CO2‐Abreinigung aus Rauchgasen mithilfe alkalischer Reststoffe

An innovative, technical approach for the reduction of CO₂ emissions is presented that utilizes alkaline wastes to capture CO₂ from flue gases in stable mineral form. Comprehensive pilot‐scale experiments were conducted with the developed flue gas scrubbing system at a power plant site. By optimizing the process parameters gas flux, CO₂ partial pressure, circulation flux and suspension liquid‐to‐solid ratio, a CO₂ binding of 40 – 90 g kg^–1 waste could be reached and up to 25 % of the CO₂ could be captured. The new technique is economically advantageous especially when both alkaline waste and CO₂ are produced on site and when the carbonated products can be used as secondary resources.     

Die Primärschritte der sauerstoffinitiierten Äthylenpolymerisation

The reactions before and during the start of the oxygen initiated polymerization of ethylene have been investigated at temperatures less than 170°C, pressures up to 2200 at and oxygen concentrations in feed up to 75 ppm. The reaction suddenly starts when starting point is reached. This is caused by inhibition of the reaction by oxygen itself. The primarily radical delivering compound is formed the easier the higher the pressure is. It must be assumed that this compound decomposes more rapidly than it is produced. The amount of oxygen being consumed in not initiating side-reactions increases with its concentration in feed.     

硫化氢泄漏后果定量分析方法及指标响应规律

为了定量分析不同场景下H2S泄漏影响范围及各参数的响应规律,为H2S的泄漏防护提供定量数据,根据统一扩散模型和重气扩散理论,应用挪威船级社的 PHAST软件研究了H2S在不同泄漏条件下的扩散特征、浓度分布及顺风距离等. 结果表明,泄漏1 min时,中孔、大孔泄漏和破裂时的立即威胁生命和健康(IDLH)浓度顺风距离从661 m增至2404 m,IDLH浓度和最高容许浓度(MAC)的顺风距离、最大云团宽度均增大了3~4倍,持续5和30 min时变化类似;相同泄漏孔径时,中孔、大孔泄漏和破裂时,IDLH顺风距离分别缩短了31.4%, 23.8%和24.7%,最大云团宽度增加了1.4~1.7倍;风速4 m/s时,大气稳定度E的IDLH和MAC顺风距离分别是大气稳定度B的2.8倍和3.8倍;大气稳定度D、风速8.5 m/s时的IDLH和MAC顺风距离分别是风速1.5 m/s时的49.2%和39.3%;顺风距离及最大云团宽度随地面粗糙度增大呈对数降低;H2S泄漏后可能造成的主要危害是中毒,其次是喷射火、闪火及爆炸. 在进行泄漏防护时可参考定量分析结果,从个体防护和安全隔离两方面考虑;泄漏影响范围可作为H2S安全隔离的边界.     

Influence of copolymerization conditions on the structure and properties of polyethylene/polypropylene/poly(ethylene‐co‐propylene) in‐reactor alloys synthesized in gas‐phase with spherical ziegler‐natta catalyst

A spherical TiCl₄/MgCl₂‐based catalyst was used in the synthesis of polyethylene/polypropylene/poly (ethylene‐co‐propylene) in‐reactor alloys by sequential homopolymerization of ethylene, homopolymerization of propylene, and copolymerization of ethylene and propylene in gas‐phase. Different conditions in the third stage, such as the pressure of ethylene–propylene mixture and the feed ratio of ethylene, were investigated, and their influences on the compositions, structural distribution and properties of the in‐reactor alloys were studied. Increasing the feed ratio of ethylene is favorable for forming random ethylene–propylene copolymer and segmented ethylene–propylene copolymer, however, slightly influences the formation of ethylene‐b‐propylene block copolymer and homopolyethylene. Raising the pressure of ethylene–propylene mixture results in the increment of segmented ethylene–propylene copolymer, ethylene‐b‐propylene block copolymer, and PE fractions, but exerts a slight influence on both the random copolymer and PP fractions. The impact strength of PE/PP/EPR in‐reactor alloys can be markedly improved by increasing the feed ratio of ethylene in the ethylene–propylene mixture or increasing the pressure of ethylene–propylene mixture. However, the flexural modulus decreases as the feed ratio of ethylene in the ethylene–propylene mixture or the pressure of ethylene–propylene mixture increases. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2481–2487, 2006