在油样品的相行为在炼油工艺条件的原位可视化
Summary
This article describes a setup and method for the in situ visualization of oil samples under a variety of temperature and pressure conditions that aim to emulate refining and upgrading processes. It is primarily used for studying isotropic and anisotropic media involved in the fouling behavior of petroleum feeds.
Abstract
To help address production issues in refineries caused by the fouling of process units and lines, we have developed a setup as well as a method to visualize the behavior of petroleum samples under process conditions. The experimental setup relies on a custom-built micro-reactor fitted with a sapphire window at the bottom, which is placed over the objective of an inverted microscope equipped with a cross-polarizer module. Using reflection microscopy enables the visualization of opaque samples, such as petroleum vacuum residues, or asphaltenes. The combination of the sapphire window from the micro-reactor with the cross-polarizer module of the microscope on the light path allows high-contrast imaging of isotropic and anisotropic media. While observations are carried out, the micro-reactor can be heated to the temperature range of cracking reactions (up to 450 °C), can be subjected to H2 pressure relevant to hydroconversion reactions (up to 16 MPa), and can stir the sample by magnetic coupling.
Observations are typically carried out by taking snapshots of the sample under cross-polarized light at regular time intervals. Image analyses may not only provide information on the temperature, pressure, and reactive conditions yielding phase separation, but may also give an estimate of the evolution of the chemical (absorption/reflection spectra) and physical (refractive index) properties of the sample before the onset of phase separation.
Introduction
油样在一个宽的温度范围，压力和反应条件的相位行为的研究可以产生非常有用的信息，其处理各种饲料炼油厂的操作者。特别地，处理单元和线路由不受控制的形成焦炭或沉积物的结垢会严重影响生产（吞吐量的损失）和能量效率（在传热阻力增加）1，2，3。可能堵塞结垢物质可能需要清理的目的，这将具有高度的负面经济影响4关机的积累造成的。导电饲料的结垢倾向的评估可以是工艺条件5的优化和精炼流的配合非常有价值的。
我们已经制定了一个在原地在我们的实验室石油稳定性的分析器，以允许油样受炼油厂工艺条件的可视化。该装置依赖于由不锈钢制成的管件和装备有在底部密封的蓝宝石窗口一个专门设计的反应器中。该装置的主要原理是在温度和压力的期望范围的反应器内的样品，将所得交叉偏振反射的摄像的照明。虽然以前的相对于这种设置集中在热裂解过程模拟减粘裂化条件6，7，8，9（其不需要高压力），反应器的设计被翻修调查加氢下样品的行为（公布工作下催化裂化高H 2压力）和水热10（热在高预裂ssure蒸汽）的条件。因此，该设备，以便在20-450℃的温度范围和0.1-16兆帕压力范围内进行操作，以维持这两个450°C和16兆帕最长为6小时的反应时间的能力进行了修订。
分析在样品的下温度，压力和反应条件的特定范围的可视信息的第一级是确定样品是否为单相或多相。这个系统是独特的，因为它允许不透明各向同性材料的可视化，并且不限于在其他工作中11所描述的各向异性材料的可视化。而样品的结垢倾向的主要指标是滴沉积出大量液体的倾向;气 – 液，液 – 液，液 – 固和更复杂的相行为可以观察到。然而，有价值的信息，也可以从液体的视觉演化，因为它仍然坎萃取ogeneous（单相）。特别是，图像的亮度是相关的折射率和样品的消光系数，而样品的颜色是在可见光范围内的光谱信息（380-700纳米）的子集，其可以是用作其化学9的描述符。
Protocol
Representative Results
Discussion
该议定书中的关键步骤
在协议中的第一个关键步骤是确保金属对蓝宝石密封的完整性，特别是当试验是在压力下进行。因此，并行性，光滑度，和密封表面的清洁度应该仔细检查，以及渗漏试验应彻底。由于蓝宝石的断裂模量是温度14的递减函数，加厚蓝宝石窗口应该在高压和高温下使用工作。作为一个指导原则，8个毫米厚蓝宝石窗口都在我们的实验旨在模拟…
Divulgazioni
The authors have nothing to disclose.
Acknowledgements
The authors acknowledge Daniel Palys for supplying Figure 12 and for his assistance in managing laboratory supplies.
Materials
| Sapphire window, C-plane, 3mm thick – 20 mm diam., Scratch/Dig: 80/50 | Guild Optical Associates | ||
| C-seal | American Seal & Engineering | 31005 | |
| Type-K thermocouple | Omega | KMQXL-062U-9 | |
| Ferrule (1/16") | Swagelok | SS-103-1 | Inserted for creating a clearance gap between the magnet and the window surface |
| Coil Heater | OEM Heaters | K002441 | |
| Temperature controller | Omron | E5CK | |
| Inverted microscope | Zeiss | Axio Observer.D1m | Require cross-polarizer module |
| Toluene, 99.9% HPLC Grade | Fisher | Catalog # T290-4 | Harmful, to be handled in fume hood |
| Methylene chloride, 99.9% HPLC Grade | Fisher | Catalog # D143-4 | Harmful, to be handled in fume hood |
| Acetone, 99.7 Certified ACS Grade | Fisher | Catalog # A18P-4 |
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