石油产品和原油 蒸气压的测定 雷德法

[中文适用范围]： 本国际标准规定了测定主要或全部由碳氢化合物成分或含有特定类型和规定最大浓度的氧化碳氢化合物的液态石油产品蒸气压的方法。 该方法不适用于这些浓度水平之外，也不适用于注释 1 中未涵盖的任何含有甲醇或其他氧化碳氢化合物的混合物。 注释 1 含有 5 个或更多碳原子的醚的最大浓度为 15% (V/V)，并且对于乙醇为 10% (V/V)。 对于高级醇，最大浓度为 7% (V/V)。 注2：就本国际标准而言，术语“%(V/V)”用于表示材料的体积分数。 对于含有甲醇或注1范围之外的其他含氧烃的石油产品，应采用干蒸气压测试方法。 对于液化石油气，应使用 ISO 4256。 该测试方法可适用于蒸气压超过10kPa的挥发性原油，但精度尚未评估。 本国际标准描述了四个程序。 程序 A 和 B 是适用于雷德蒸气压高达 180 kPa 的产品的替代设备配置，程序 C 适用于雷德蒸气压高于 180 kPa 的液体产品，程序 D 适用于雷德蒸气压约为 180 kPa 的航空汽油。 50 kPa。 蒸气压是挥发性液体的重要物理性质，对汽车和航空汽油具有关键的性能影响。 蒸气压也是影响大气蒸发的特性之一，因此越来越多地用于与排放和空气质量控制相关的法规中。 蒸气压也是限制转移操作期间设备操作性能和安全性的关键特性。 注：由于外部大气压力被均热室最初的大气压力抵消，因此雷德蒸汽压大约是 37.8 ℃ 时的“绝对”蒸汽压。 由于样品的轻微汽化以及密闭空间中水蒸气和空气的压力，雷德蒸气压与样品的真实蒸气压不同。 [外文原描述]： This International Standard specifies a method for the determination of the vapour pressure of liquid petroleum products consisting of essentially or wholly of hydrocarbon components, or containing oxygenated hydrocarbons of specific types and at specified maximum concentrations. The method does not apply outside these concentration levels, nor to any blends containing methanol or other oxygenated hydrocarbons not covered in note 1. NOTE 1 The maximum concentration of ethers containing 5 or more carbon atoms is 15 % ( V / V ), and for ethanol is 10 % ( V / V ). For higher alcohols, the maximum concentration is 7 % ( V / V ). NOTE 2 For the purposes of this International Standard, the term "%(V/V)" is used to represent the volume fraction of a material. For petroleum products containing methanol, or other oxygenated hydrocarbons outside the scope of note 1, a dry vapour-pressure test method should be used. For liquefied petroleum gases, ISO 4256 should be used. The test method may be applied to volatile crude petroleum with a vapour pressure exceeding 10 kPa, although the precision has not been evaluated. Four procedures are described in this International Standard. Procedures A and B are alternative apparatus configurations for products with a Reid vapour pressure up to 180 kPa, Procedure C is applied to liquid products with a Reid vapour pressure above 180 kPa, and Procedure D applies to aviation gasolines with a Reid vapour pressure of approximately 50 kPa. Vapour pressure is an important physical property of volatile liquids, and has critical performance implications for automotive and aviation gasolines. Vapour pressure is also one of the properties affecting atmospheric evaporation, and is therefore increasingly used in regulations relating to emissions and air quality control. Vapour pressure is also a critical property limiting the performance and safety of operation of equipment during transfer operations. NOTE Because the external atmospheric pressure is counteracted by the atmospheric pressure initially in the vapour chamber, the Reid vapour pressure is approximately the "absolute" vapour pressure at 37,8 °C. The Reid vapour pressure differs from the true vapour pressure of the sample owing to slight vaporization of the sample and the pressure of water vapour and air in the confined space.