Solid-State NMR Investigation of Cold-Flow Properties\nof Hydrotreated Vegetable Oils and Their Blends with Petroleum Diesels

The\ncold-flow properties of hydrotreated vegetable oils (HVO) and\n their blends with petroleum diesel were investigated by solid-state\nNMR (SSNMR). The fraction of protons in the crystallites was successfully\ndetermined at temperatures going from 30 °C to −50 °C,\noffering a way to precisely monitor the crystallization process occurring\nduring the cool-down of hydrocarbons. The Magic Sandwich Echo experiment\nused in this work displayed a higher sensitivity compared to other\nmethods such as cloud point, pour point, and cold filter plugging\npoints, with a detection of the onset of crystallization by SSNMR\nup to 15 °C with respect to other techniques. The properties\nof three distinct HVO and of their blends with petroleum diesel were\ndetermined and related to their detailed chemical composition. Results\nshowed that a high branching level was the primary factor impacting\nthe onset of crystallization of the HVO. The carbon number distribution\nwas observed to impact the rate of crystallization as a function of\nthe temperature. Lastly, blending petroleum diesel with HVO was demonstrated\nto keep the cold-flow properties of the diesel unchanged at 10 wt\n% mixing. In contrast, a shift of the cold-flow properties of the\nblends toward the HVO behavior was detected at 30 and 50 wt % mixing,\nwith either a negative or positive impact depending on the chemical\ncomposition of the added HVO.