利用NIRS和RI技术测试石油流体析蜡温度新方法

析蜡温度是重要的石油流体性质参数，得到准确的析蜡温度是保证含蜡原油管道安全输送的前提。提出了近红外光谱温度扫描测试法和折射率测试法，改进了近红外光谱波长扫描测试法，并从可靠性、灵敏性和稳定性等方面与常用的偏光显微镜法和差示扫描量热法进行比较。结果表明，近红外光谱法和折射率法可以得到可靠的测试结果，并具有较高的灵敏性和稳定性；实验操作和数据分析方法简单，测试结果不易受到制样过程影响，尤其适合挥发性较强的油样。此外，近红外光谱法测试时油样处于运动状态，可有效减小过冷度的影响，但与实际管输条件仍存在一定差别。

New measurement methods for wax appearance temperature of petroleum fluids using NIRS and RI techniques

Wax appearance temperature (WAT) is an important parameter of petroleum fluids. Obtaining accurate wax appearance temperature is a prerequisite for ensuring the safe transportation of waxy crude oil pipelines. New measurement methods were proposed in this study, including temperature scanning method using near infrared spectroscopy (NIRS) and refractive index (RI) method. Furthermore, wavelength scanning method using NIRS was improved in its testing and data analysis process. In addition, these methods were compared with two commonly used ones, polarizing microscopy (PM) and differential scanning calorimetry (DSC). The results showed that reliable WAT results could be obtained by NIRS and RI methods with high sensitivity and stability. The measurement results were less susceptible to the simple testing and analysis process, especially suitable for volatile samples. Moreover, the stirring in the testing process of NIRS methods effectively reduced the influence of supercooling degree, while it was still different from the flowing condition in real pipelines.