Online detection of CFPP of diesel mixed oil in multi-product pipeline by near infrared spectroscopy

It is necessary to analyze the cold filter plugging point (CFPP) with wide range distribution of diesel mixed oil in real time for timely precise judgement of the mixed oil interface formed by the sequential transportation of different grade of diesel fuel in pipeline. This study investigated an online detection method of CFPP with wide range distribution of 0# and -35# diesel mixed oil using near-infrared (NIR) spectroscopy. 385 samples of 0# diesel, -35# diesel, and their blends were collected, and their CFPP were determined using the laboratory SH/T 0248 standard method, while their NIR spectra were also collected by an online NIR detection system. A segmented partial least squares (PLS) modeling strategy was used to establish the multivariate calibration models of CFPP with a wide range of CFPP (-50~3°C). The absolute prediction deviation of the CFPP NIR prediction values of the online sample of 0# diesel and -35# diesel blend oil with a range of -33~4°Cand the reference values measured by SH/T 0248 test method is no more than 3°C, not exceeding the reproducibility error limit of the SH/T 0248 test method (3~5°C) in the range (-33~-4°C). It means that the results determined by the two methods are consistent, and NIR spectroscopy can be used for online detection of the CFPP of mixed oil of 0# diesel and -35# diesel in pipeline. This NIR method will provide real-time data support for precise cutting of the blend.