.jpg)
Image Credit: mmmx/Shutterstock.com
Thermal analysis describes an array of techniques that are essential to the petrochemical industry to characterize the range of different materials produced, from crude oil to gasoline, diesel, liquid petroleum gas and lubricants.
Many of these techniques are complementary and when used in conjunction can provide a comprehensive ‘fingerprint’ of physical and chemical properties for the petrochemicals being studied
This manual provides an excellent overview of the range of thermal techniques available, their most suitable applications and how they may be combined by using analysis case study examples. The main techniques discussed are Differential Scanning Calorimetry (DSC) and Thermal Gravimetric Analysis (TGA), and how they can be used to study complex hydrocarbons such as crude oil, wax and coal.
Section two examines the use of DSC in characterisation of various petroleum products from heavy crude oil to light petroleum distillates. DSC is demonstrated as a fundamental technique for rapid reliable characterization. By using cooling and crystallization measurements the glass transition temperature and melting behavior can provide an excellent profile of the physical properties of petroleum derivatives.
由于测得的曲线是石油混合物的特征“指纹”，因此该技术也被标记为未知石油样品。另一个重要的领域是石油级分或聚合物的氧化稳定性，在第三和六个DSC中，分别用于确定氧化诱导温度和氧化诱导时间，以评估材料的氧化稳定性。这些是快速分析技术，其中氧化开始的温度和开始氧化的时间是从DSC曲线确定的，而所获得的值是每个样品的特征。
Oils and lubricants are an essential part of everyday life and section four shows how a standard test method can be conducted rapidly using thermal methodology. As oils are constantly used at high temperature there may be loss of volatile components and consequent increase in viscosity. The Noack evaporation test is a widely used standard test method for measuring the evaporation loss from lubricating oils. According to ILSAC GF-3 and API-SL specifications, the loss by evaporation must not exceed 15%. Automated TGA is an excellent way to provide pass/fail data on large sample sets. The soot analysis of engine oil is another important area in the study of lubricants. Section seven demonstrates a combined TGA and DSCD method to provide essential data about diesel engine oil lifetime changes as part of the ASTM D5967 standard test method.
固体石油化合物（例如煤和聚合物）的热分析带来了新的挑战，例如样品的均匀性，分析的慢速和准确的标准方法的开发。在第五节中，这些问题在一种新的标准方法中证明了煤的快速热重分析。定量确定水分，挥发性化合物，化学结合的碳和灰分含量用于定义不同类型的煤炭的质量和销售性。
High ash content is unwelcome as inert material increases transport and waste disposal costs, and this also means that power station heat exchangers have to be cleaned more frequently. In this section, TGA was used to characterize coal samples (showing when combustion and degassing are complete) under automated sample control using the METTLER TOLEDO STAR system and a special temperature program. The method can analyze 35 coal samples per day providing a new rapid accurate analytical method.
第八节通过准备已知的油含量样品的校准曲线，比较了使用DSC的各种油/蜡混合物的熔融行为。任何样品油含量都可以通过简单地测量其整体熔化焓并指校准曲线来估算。通过直接分析DSC加热曲线来获得测量。
该信息已从梅特勒·托莱多（Mettler Toledo）提供的材料中采购，审查和调整。亚博网站下载
有关此消息来源的更多信息，请访问Mettler Toledo-热分析。