Presser Cary, Nazarian Ashot
Chemical Sciences Division, Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899, United States.
Energy Fuels. 2017 Jul;31(7):6732-6747. doi: 10.1021/acs.energyfuels.7b00534. Epub 2017 Jun 30.
A novel laser-heating technique, referred to as the laser-driven thermal reactor (LDTR), was used to determine sample thermal (exothermic/endothermic) behavior, specific heat release rate, and total specific heat release of three volatile single-component liquid hydrocarbons, i.e., -decane, -butylcyclohexane and -butylbenzene. The objective was to demonstrate measurement repeatability and extend the LDTR model from earlier investigations. The experimental apparatus consists of a copper sphere-shaped reactor mounted within a vacuum chamber, with sample and substrate supported on a thermocouple near the center of the reactor. The reactor is heated from opposing sides by a near-infrared laser to achieve nearly uniform sample temperature. The change in temperature with time (i.e., thermogram) is compared to a previously recorded baseline (no liquid sample) thermogram. A model, based on thermal energy conservation, is used to evaluate the thermograms for the thermochemical characteristics of interest. This study represents a step toward applying this technique to more complex volatile multi-component fuels of unspecified composition. Results for the LDTR were compared with a differential scanning calorimetry/thermal gravimetric analysis (DSC/TGA) instrument. The model analysis was extended to include an estimation of the hydrocarbon mass change with increasing temperature, based on the temporal change in the specific heat release rate. An estimate of the total specific heat release was obtained for these three liquid hydrocarbons and found to be consistent with the literature values when the measurements were carried out under suitable operating conditions.
一种被称为激光驱动热反应器（LDTR）的新型激光加热技术，被用于测定三种挥发性单组分液态烃（即正癸烷、仲丁基环己烷和仲丁基苯）的样品热行为（放热/吸热）、比热释放率和总比热释放量。目的是证明测量的可重复性，并扩展早期研究中的LDTR模型。实验装置由安装在真空室内的铜球形反应器组成，样品和基底支撑在反应器中心附近的热电偶上。反应器由近红外激光从相对的两侧加热，以实现样品温度几乎均匀。将温度随时间的变化（即热谱图）与先前记录的基线（无液体样品）热谱图进行比较。基于热能守恒的模型用于评估感兴趣的热化学特性的热谱图。这项研究代表了将该技术应用于成分未指定的更复杂挥发性多组分燃料的一个步骤。将LDTR的结果与差示扫描量热法/热重分析（DSC/TGA）仪器的结果进行了比较。基于比热释放率的时间变化，将模型分析扩展到包括对烃质量随温度升高的变化的估计。获得了这三种液态烃的总比热释放量的估计值，并且当在合适的操作条件下进行测量时，发现该估计值与文献值一致。
