Chong Yang Du

Readily degradable low-dose hydrate inhibitors are of great significance for flow assurance in the petroleum industry. Recently, α-lipoic acid (LA) was shown to undergo ring-opening reaction via reversible addition–fragmentation chain-transfer copolymerization with acrylamides to introduce labile disulfide bonds into the stable vinyl polymer backbone. Here, LA was copolymerized with acryloyl morpholine (AM) to evaluate their performance as kinetic hydrate inhibitors. Degradability was confirmed for the copolymers with 20 mol.% LA (AM/LA20, M_n = 19 → 9 kDa) after disulfide reduction. Thermogravimetric analysis also indicated faster thermal degradation of AM/LA due to the incorporation of weaker S-S and S-C linkages. Increasing LA content reduced hydrophilicity, and the copolymers were treated with NaOH to ensure water solubility. However, at 700 ppm, poly(AM) homopolymer reduced methane consumption during hydrate growth to 54% with respect to the uninhibited system, while gas consumption for the carboxylate AM/LA20 reached 78%. An advantageous feature of LA is its carboxylic acid, allowing desired functionalities to be grafted onto the degradable copolymer. Isopropyl amine (IPAm) was coupled with LA to form an amide known to be effective during hydrate inhibition (LA(IPAm)). The copolymer AM/LA(IPAm)20 demonstrated better water solubility compared to the original AM/LA20. Furthermore, the desirable IPAm functionality allowed the hydrate inhibition to be re-established at 54%, nearly recovering the performance of the poly(AM) homopolymer. This article assesses the application of LA and LA derivatives as building blocks for degradable amide-based kinetic hydrate inhibitors by validating their degradability with material characterizations and their inhibition performance during structure I hydrate growth.

The connection technology between silica Fiber Bragg Grating sensors (FBGs) and ultra-high temperature ceramic composites (UHTCs) is solved to measure the temperature and strain at the same time when the structural temperature higher than 500°C in this paper. A series experiments were carried out to compare the connection properties, and then the best adhesive was selected. A lot of attempts have been made to choose the best curing process. The experiments were carried out at 500°C, and results shown that the response wavelength and the heated temperature have positive linear relationship. The wavelength will increase 0.0096nm with the temperature rise 1°C, and 1με changes will induce the response wavelength increase 0.002nm. A feasible method for high temperature measuring based fiber Bragg grating was given in this study, and the results of this study can be used as an important reference data for hot structure the thermal protection systems designing.