Functionalized Superparamagnetic Iron Oxide Nanoparticles as a Sustainable Approach for Gas Hydrate Control

Gas hydrate blockage in multiphase flow lines is a critical issue in upstream operations. One method to prevent this from happening is by the use of kinetic hydrate inhibitors (KHIs). KHIs are polymers containing tailored amphiphilic groups. These polymers often have limited marine biodegradability, and their recovery and recycling to reduce operational costs remain a challenge. A novel approach involves attaching KHIs to magnetic nanoparticles, enabling recovery and recycling without environmental discharge. We have developed superparamagnetic iron oxide nanoparticles (SPIONs) reacted first with vinyltrimethoxysilane (VTMS) and then coated with <i>N</i>-vinylpyrrolidone/<i>N</i>-vinyl caprolactam (VP/VCap) copolymer chains using radical polymerization of the VP and VCap monomers (SPIONs-VTMS-VPVCap). These nanoparticles are stable in aqueous solutions with a particle size of 10 nm and a dispersion size of 205 nm. High-pressure tests demonstrated that SPIONs-VTMS-VPVCap performed comparably to the free VP/VCap copolymer, achieving a hydrate formation onset temperature (<i>T</i> _o) of 12.9 °C at 5000 ppm. Significantly, the magnetic KHIs were successfully recovered and reused multiple times without performance loss. The solution exhibited a high cloud point (80 °C) and compatibility with <i>n</i>-butyl glycol ether (BGE), enhancing the performance. Adding 5000 ppm of BGE lowered the hydrate formation <i>T</i> _o to 7.3 °C, a 9.7 °C improvement compared to no additive. These results establish a proof of concept for recyclable magnetic KHIs, offering a sustainable solution to eliminate chemical discharge in marine environments while maintaining effective hydrate inhibition.