The prediction of the flash point for binary aqueous-organic solutions

A mathematical model, which may be used for predicting the flash point of aqueous-organic solutions, has been proposed and subsequently verified by experimentally-derived data. The results reveal that this model is able to precisely predict the flash point over the entire composition range of binary aqueous-organic solutions by way of utilizing the flash point data pertaining to the flammable component. The derivative of flash point with respect to composition (solution composition effect upon flash point) can be applied to process safety design/operation in order to identify as to whether the dilution of a flammable liquid solution with water is effective in reducing the fire and explosion hazard of the solution at a specified composition. Such a derivative equation was thus derived based upon the flash point prediction model referred to above and then verified by the application of experimentally-derived data.     

Determination of flash point in air and pure oxygen using an equilibrium closed bomb apparatus

The standard closed testers for flash point measurements may not be feasible for measuring flash point in special atmospheres like oxygen because the test atmosphere cannot be maintained due to leakage and the laboratory safety can be compromised. To address these limitations we developed a new "equilibrium closed bomb" (ECB). The ECB generally gives lower flash point values than standard closed cup testers as shown by the results of six flammable liquids. The present results are generally in good agreement with the values calculated from the reported lower flammability limits and the vapor pressures. Our measurements show that increased oxygen concentration had little effect on the flash points of the tested flammable liquids. While generally regarded as non-flammable because of the lack of observed flash point in standard closed cup flash point testers, dichloromethane is known to form flammable mixtures. The flash point of dichloromethane in oxygen measured in the ECB is -7.1 degrees C. The flash point of dichloromethane in air is dependent on the type and energy of the ignition source. Further research is being carried out to establish the relationship between the flash point of dichloromethane and the energy of the ignition source.     

Flash Point: Evaluation, Experimentation and Estimation

The flash point is an important indicator of the flammability of a chemical. For safety purposes, many data compilations report the lowest value and not the most likely. This practice, combined with improper documentation and poor data storage methods, has resulted in compilations filled with fire-hazard data that are inconsistent with related properties and between members of homologous chemical series. In this study, the flash points reported in the DIPPR^® 801 database and more than 1,400 other literature values were critically reviewed based on measurement method, inter-property relations, and trends in chemical series. New measurements for seven compounds illustrate the differences between experimental flash points and data commonly found in fire-hazard compilations. With a critically reviewed set of experimental data, published predictive methods for the flash point were evaluated for accuracy.     

Physical characteristics of baked carbon mixes employing coal tar and petroleum pitches

A study of the physical characteristics of baked carbon mixes employing coal tar and petroleum pitches as the binder has been made to explore their relative suitability in the fabrication of carbon products. The study reveals that coal tar pitch is the most suitable binder and a petroleum pitch of the same softening point leads to a carbon product of much inferior characteristics. Raising the softening point of the petroleum pitch from 78 to 150° C or adding 10 parts of carbon black in the lower softening point pitch, increases the density, strength and also the electrical resistivity of the baked carbons. The addition of 10 parts of carbon black to the higher softening point petroleum pitch leads to a carbon product with further improved values of density and strength, which are comparable to those obtained with the coal tar pitch. However, the electrical resistivity also is marginally increased. It appears that a petroleum pitch of high aromaticity may fulfill the requirements expected of a good binder.     

A general model for predicting the flash point of miscible mixtures

A mathematical model is presented for predicting the flash point of miscible mixtures. This model is reducible and adequate for some specified systems as proposed previously. Except for multiple aqueous-organic solutions, the predictive capability of the reduced form for other miscible mixtures, including binary aqueous-organic solutions and flammables-only analogues, has been verified previously. The model was validated using the ternary aqueous-organic solutions, water+methanol+ethanol/isopropanol. The results of the study confirm that the model predicts the flash points of these solutions by utilizing the flash points of the individual components. Further, if the binary interaction parameters for a ternary aqueous-organic solution are not accessible, a model based upon the binary interaction parameters of the binary solutions may provide a very acceptable means of predicting the flash point for such a ternary solution through comparison of the predicted and experimental data, as demonstrated in this study.     

Measurement of flash points: Apparatus,methodology, applications

The flash point provides a simple, convenient index for the flammability of diverse materials. In this paper, flash point apparatus and methodology are surveyed and some applications highlighted, including use in the study of spill control agents for flammable solvents. The reliability of the Setaflash closed tester is confirmed. The formulation and use of liquid mixtures to assure the performance of flash point testers is described.     

Performance and application of far infrared rays emitted from rare earth mineral composite materials

Rare earth mineral composite materials were prepared using tourmaline and cerous nitrate as raw materials. Through characterization by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, dynamic contact angle meter and tensiometer, and Fourier transform infrared spectroscopy, it was found that the composite materials had a better far infrared emitting performance than tourmaline, which depended on many factors such as material composition, microstructure, and surface free energy. Based on the results of the flue gas analyzer and the water boiling test, it was found that the rare earth mineral composite materials could accelerate the combustion of liquefied petroleum gas and diesel oil. The results showed that the addition of Ce led to the improvement of far infrared emitting performance of tourmaline due to the decrease of cell volume caused by the oxidation of more Fe2+ ions and the increase of surface free energy. The application of rare earth mineral composite materials to diesel oil led to a decrease in surface tension and flash point, and the fuel saving ratio could reach 4.5%. When applied to liquefied petroleum gas, the composite materials led to the enhanced combustion, improved fuel consumption by 6.8%, and decreased concentration of CO and O2 in exhaust gases by 59.7% and 16.2%, respectively; but the temperature inside the flue increased by 10.3%.     

液化石油气泄漏的危险性分析及其事故后果评价方法

液化石油气（LPG）在其运输和存储过程中存在着各种与火灾和爆炸相关的危险性。由于LPG的泄漏可能导致包括闪火，不可控蒸气云爆炸，沸腾液体膨胀蒸汽爆炸等一系列灾害的发生，针对上述的各种灾害的具体发生条件及其危险性进行了分析；在事故后果评价中采用量化风险分析，提出了沸腾液体膨胀蒸汽爆炸和不可控蒸气云爆炸对周围人员可能造成伤害的评价方法。     

稻壳类生物沥青微观作用机理研究

为了探究稻壳类生物质油替代石油沥青的微观作用机理,以稻壳类生物质油和6种石油沥青为原材料,制备稻壳类生物沥青。采用针入度、软化点和延度指标评价稻壳类生物沥青的物理性能,通过傅里叶红外光谱实验(FTIR)和高温凝胶色谱实验(GPC)探究稻壳类生物沥青的微观作用机理。研究表明,稻壳类生物质油会使石油沥青的针入度和延度增大,同时使软化点略有降低;稻壳类生物质油与6种石油沥青的官能团相似,且生物沥青制备时未产生新的官能团;随着稻壳类生物质油的掺加,6种生物沥青中的小分子和中分子含量增加,大分子的含量变化不大,稻壳类生物质油小分子和中分子含量较多,生物沥青的数均分子量M_n和重均分子量M_w均降低。稻壳类生物质油的加入,使石油沥青的低温性能提高,流动性增大,高温性能稍有降低但并不会降低石油沥青的高温等级,稻壳类生物质油可以作为石油沥青的替代材料使用。     

以PR方程为基础的氧—氮—氩系统气液平衡计算及在空分操作中应用

综合分析了多组分相平衡理论特点,介绍利用Peng—Robinson(PR)立方型状态方程进行氧—氮—氩系统气液平衡计算的方法(泡点、露点和闪蒸计算),对该计算方法的准确性进行分析和验证,并举例分析了空分设备的运行工况。     

Impact flash jet initiation phenomenology

Impact flash is caused by emission from a jet of shocked material formed through a shock interaction analogous to the process which occurs in a shaped charge. Shaped charge theory predicts that a jet will form when the impact angle between two colliding surfaces is greater than an initiation angle criterion which is a function of material properties and impact velocity. Because the effective impact angle continuously sweeps over a range of values as a spherical particle impacts a flat target, this jet initiation angle criterion is satisfied at some point during the penetration process. A simple model has been developed which predicts the jet initiation from either the target or the particle material. This jet initiation model, (JIM) resolves an apparent discrepancy between previous studies of the dependence of particle and target materials on the flash intensity and provides strong evidence that the impact flash signature is a characteristic of the material in which jet initiation occurs. This model also provides a reasonable explanation for the unusual flash signatures from the impact of carbon particles against gold targets, which show a decrease in flash intensity with increasing impact velocity between 5 and 15 km/s.     

A non-ideal model for predicting the effect of dissolved salt on the flash point of solvent mixtures

Flash point is one of the major quantities used to characterize the fire and explosion hazard of liquids. Herein, a liquid with dissolved salt is presented in a salt-distillation process for separating close-boiling or azeotropic systems. The addition of salts to a liquid may reduce fire and explosion hazard. In this study, we have modified a previously proposed model for predicting the flash point of miscible mixtures to extend its application to solvent/salt mixtures. This modified model was verified by comparison with the experimental data for organic solvent/salt and aqueous-organic solvent/salt mixtures to confirm its efficacy in terms of prediction of the flash points of these mixtures. The experimental results confirm marked increases in liquid flash point increment with addition of inorganic salts relative to supplementation with equivalent quantities of water. Based on this evidence, it appears reasonable to suggest potential application for the model in assessment of the fire and explosion hazard for solvent/salt mixtures and, further, that addition of inorganic salts may prove useful for hazard reduction in flammable liquids.     

钢轨闪光焊接后轨腰原始裂纹的特征

在U75V钢轨的端部轨腰处采用线切割和高频疲劳预制轨腰裂纹,并进行闪光焊接,在放置7a（天）后对焊接接头试样的裂纹表面形貌和脱碳现象进行了分析和研究。研究表明,预制轨腰裂纹与其他轨腰焊接水平裂纹的宏观和微观区别,为今后焊接接头处的轨腰水平裂纹质量检验和判断提供了依据。     

进口航空煤油卸货前现场快速检测方法评价

研究了适合进口航空煤油卸货前现场检测的快速检测项目,对电导率、水分离指数、闪点、冰点和馏程的快速检测方法的有效性和作用进行了分析和评价。按照美国材料与试验协会标准可以使用电导率测量仪和水分离测量仪对航空煤油的电导率和水分离指数进行现场快速检测,使用小型傅里叶中红外光谱仪可以实现闪点、冰点和馏程的现场快速检测,为航空煤油的质量进行预判,以降低在卸货后发现质量不合格所造成的风险。     

石油沥青对乳化法煤沥青基炭微球的改性机理

通过在煤焦油沥青中添加石油沥青获得沥青甲苯胶体溶液,然后与聚乙烯醇(PVA)的甘油溶液乳化,制备了煤沥青基炭微球.为了阐明沥青在甲苯中的溶解性及其与PVA中憎水的亚甲基亲合力对于微球形成的影响,在煤沥青中添加了不同比例的与PVA中憎水的亚甲基更具亲合力的石油沥青,建立了一个微球成形机理的模型.研究发现,添加石油沥青可以促进乳化液中沥青分子与分散剂界面上表面活性剂分子的取向稳定性,从而明显改善沥青微球的球形度.石油沥青的添加降低了混合后沥青的软化点,为使沥青微球的软化点高于空气氧化始温,需要选择适当的添加比例.     

Flash-point prediction for binary partially miscible mixtures of flammable solvents

Flash point is the most important variable used to characterize fire and explosion hazard of liquids. Herein, partially miscible mixtures are presented within the context of liquid-liquid extraction processes. This paper describes development of a model for predicting the flash point of binary partially miscible mixtures of flammable solvents. To confirm the predictive efficacy of the derived flash points, the model was verified by comparing the predicted values with the experimental data for the studied mixtures: methanol+octane; methanol+decane; acetone+decane; methanol+2,2,4-trimethylpentane; and, ethanol+tetradecane. Our results reveal that immiscibility in the two liquid phases should not be ignored in the prediction of flash point. Overall, the predictive results of this proposed model describe the experimental data well. Based on this evidence, therefore, it appears reasonable to suggest potential application for our model in assessment of fire and explosion hazards, and development of inherently safer designs for chemical processes containing binary partially miscible mixtures of flammable solvents.     

Lubricant Oils as a Certified Reference Material for Cleveland Open Cup Flash Point Testers

The flash point is an important indicator for the flammability of the liquid materials and also in the development of safe practices for handling and storage of these materials. The production of certified reference materials is essential to guarantee the performance of the flash point measurement apparatus so that it can be trusted and acceptable for its intended use. In this work lubricant oils of high molecular weight hydrocarbons (HM1, and HM2) were tested as certified reference materials in accordance with ISO guide 34 and 35 by using the high flash point temperature detector Cleveland-open cup as per ASTM D-92. The selected oils were tested for uncertified properties like pour point, viscosity, cloud point, density, and total acid number. The thermal analysis techniques DSC, and TGA were used to ensure the thermal stability of the lubricant oils and its ability to be used as high temperature flash point reference material. The certified value of the flash point temperature was assigned upon evaluation of the data acquired in an inter-laboratory comparison involving expert laboratories using the same measurement method. The certified values of the candidate reference materials with expanded uncertainty (coverage factor K = 2, approximate 95% confidence level) calculated using the results of the characterization, calibration (organizer lab), homogeneity, and stability assessment were 232 ± 9 °C for HM1, and 242 ± 10 °C for HM2.     

Analysis of Gasolines by FT-IR Spectroscopy

An experimental and computational protocol was established for the simultaneous determination of several key gasoline properties from a single Fourier transform infrared (FT-IR) spectrum. The study has shown that midband FT-IR spectroscopy combined with multivariate calibration analysis is a versatile, efficient, and accurate technique for the simultaneous estimation of key gasoline properties within about 1 min with less than 2 mL of sample. The FT-IR-derived values of gasoline properties include research and motor octane numbers, aromatic, olefinic, and saturated hydrocarbon content, benzene content, and concentrations of ethanol, methyl tert-butyl ether, and total oxygen. Concentrations of other oxygenated compounds are expected to be equally predictable. However, since these oxygen-containing species have not been adequately represented among the currently commercially available gasoline samples, their calibration may only be achieved using laboratory fuel blends. Midrange boiling point data may also be estimated. Fuel properties determined by minor concentrations of fuel components, e.g., flash point, sulfur content, etc., may not be modeled because the corresponding FT-IR signals are below detection limits of presented experimental protocol. The precision of this procedure was shown to be comparable to reproducibility of the standard laboratory analyses used for direct measurement of specific fuel properties, with squared correlation coefficient (R(2)) ranging from 0.94 to 0.99 between the two sets of measurements. This new methodology could increase the corresponding output of the petroleum laboratories by a factor of over 200 to 1 while maintaining data integrity and minimizing sample requirements, environmental hazards, and cost.     

带闪蒸型经济器的风冷螺杆热泵机组性能的实验研究

研究了带闪蒸型经济器风冷螺杆热泵机组对制热性能的影响,理论分析了补气压力的变化对机组制热性能的影响。研究表明,带闪蒸型经济器热泵螺杆机组制热量随经济器的补气压力的减小而增大,压缩机功率也随经济器的补气压力的减小而增大,压缩机的COP随着经济器的补气压力的升高先升高再降低,存在最佳效率的补气压力点。实验测试了比最佳补气压力点偏高的经济器补气压力对机组性能的影响,理论计算结果和实测数据吻合良好。     

Structural characteristics of peat bitumen and peat/petroleum bitumen blends,and consideration of their potential use as road binder materials

Bitumen derived from peat was blended with petroleum bitumen and subjected to laboratory evaluation for use as road binder material. Standard empirical procedures used included penetration, softening point and Fraass brittle point determinations. Rheological behaviour has been assessed at low shear rate using a sliding plate microviscometer and at high shear rate using a cone and plate instrument. Thermal analysis techniques including calorimetry and dielectric thermal analysis have been used to obtain fundamental structural information. Properties have also been measured after accelerated ageing. Peat bitumen is shown to differ significantly from petroleum bitumen in having a relatively high (30%) crystal content; however, as crystal melting commences below 20 ° C, the initial effect obtained in blending with petroleum bitumen is that of a plasticizer, reducing blend viscosity and increasing penetration. Crystallinity in the blends is lower than expected and this is ascribed to diffusional control of the crystallization process. Peat bitumens show a marked propensity to harden on heating, presumably due to condensation reactions increasing molecular weight, and this more than compensates for the plasticizing effect. The results suggest that age hardening will limit technically useful blends to a maximum of 17% wt/wt peat bitumen.