Fuel ( IF 6.7 ) Pub Date : 2021-03-31 , DOI: 10.1016/j.fuel.2021.120584
Jia Meng , Jae Bem You , Hao Hao , Xiaoli Tan , Xuehua Zhang
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Paraffinic froth treatment (PFT) is an essential step in oilsands extraction. The ability to quantitatively understand and control asphaltene precipitation induced by solvent dilution is key to technology innovation in PFT process. In this work, we investigate the early stage of asphaltene precipitation in a model oil system in response to diffusive solvent addition in quasi-2D confinement. Using total internal reflection fluorescence microscope, we provide direct visualization of the size distribution and structural characteristics of asphaltene precipitates with a spatial resolution of 200 nm and temporal resolution of 250 ms. Our results show the correlation between the size and number of the asphaltene particles and the concentration of the paraffinic solvent in the diluent. Notably the aggregates were found to consist of primary submicron particles with a similar size from 200 nm to 400 nm in radius. These particles may be the primary elementary units that aggregate and form bigger particles via aggregation. The growth time of asphaltene particles decreases with increase n-pentane concentration in the observation area. The findings from this work provide new insight into the effects of solvent mixing on the size distribution and morphological characteristics of asphaltene precipitates that are important for association with water and solids and separation properties.
中文翻译:
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在模型油系统中,通过全内反射荧光显微镜原位揭示了早期沥青质沉淀过程中的初级亚微米颗粒
石蜡泡沫处理(PFT)是油砂提取中必不可少的步骤。定量理解和控制由溶剂稀释引起的沥青质沉淀的能力是PFT工艺技术创新的关键。在这项工作中,我们研究了准油品模型中沥青质沉淀的早期阶段,以响应准二维限制条件下扩散溶剂的添加。使用全内反射荧光显微镜,我们可以直接观察沥青质沉淀物的尺寸分布和结构特征,其空间分辨率为200 nm和250 ms的时间分辨率。我们的结果显示出沥青质颗粒的大小和数量与稀释剂中链烷烃溶剂浓度之间的相关性。值得注意的是,发现聚集体由尺寸从200 nm至400 nm相似的初级亚微米颗粒组成半径。这些颗粒可以是主要的基本单元,其通过聚集而聚集并形成更大的颗粒。随着观察区内正戊烷浓度的增加,沥青质颗粒的生长时间减少。这项工作的发现为溶剂混合对沥青质沉淀物的尺寸分布和形态特征的影响提供了新的见解,这对于与水和固体以及分离特性的结合非常重要。