| Due to the excellent waterproof, decay resistance and adhesion performance, bitumen becomes a supporting highway construction material, the quality of which directly affect road performance and road life. Bitumen depends on crude oil strongly, and high-quality road bitumen couldn’t be produced by crude oil distillation in China, so we usually use soft and hard components (furfural extract oil and propane bitumen) to mix heavy traffic road bitumen. The relative proportion of each component of the furfural extract oil and propane bitumen is the key to obtain road bitumen with high quality. Now, the determination of SARA and wax content mainly refer to industry standard, whose analysis process is tedious and time-consuming. The speed of high performance liquid chromatography (HPLC) and thin layer chromatography-flame ionization detection (TLC-FID) method is faster, but the correction factor is difficult to determine, because of the complex composition of petroleum products and raw material variability. Therefore, the study on accurate and efficient analysis of quality metrics is extremely meaningful to quality control on heavy oil. Infrared spectroscopy analysis technique develops rapidly and is widely used in the agricultural, food and medicine, petrochemical field, thanks to its nondestructive, efficient, on-line and real-time features. Aim to solve the problems existing in the quality control of bitumen production process, a rapid analysis system was designed and a new method of attenuated total reflection infrared spectroscopy was proposed to quickly analyze multiple quality indicators of bituminous materials.In this study, sixty two extract oil samples were collected and their saturates and aromatics content data were determined according to the standard NB/SH/T0509-2010, then the total contents of resins and asphaltenes calculated by the subtraction method in the percentage of weight. Based on the partial least squares(PLS), calibration models for saturates, aromatics, and resins+asphaltenes contents were established using attenuated total reflection FTIR spectroscopy, with their SEC,1.43%,0.91%and1.61%, SEP,1.56%,1.24%and1.81%, respectively, less than the reproducibility error (4.0%,2.4%,4.3%) stipulated in the standard method, and the model prediction accuracy is far superior to standard method. Since the propane bitumen is prone to cool and congeal, a specific temperature controller was designed to make propane bitumen soften by heating and to make the sample contact closely with crystal so as to stabilize the test. The spectra of one hundred and twelve propane bitumen were collected and their wax content data were determined according to the standard SH/T0425-2003. A quantitative calibration model for wax content was established using partial least squares(PLS), with SECO.16%and SEP0.19%, less than the reproducibility error (0.5%) stipulated in the standard method. Based on the model, three samples were selected to test repeatability; the results met the precision requirement of the standard method. Compared with the existing standard methods, the new method is fast, easy to operate and could increase the efficiency of the analysis of heavy oil significantly.In this study, eleven bitumen of different places and grades were collected. There were excellent correlation between the infrared spectra and their needle penetration and softening point with perfect fitting results. The study confirmed that infrared spectroscopy is feasible for quality analysis of bitumen and have favorable application foreground in the areas of quality detection and evaluation of bitumen. |
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