(152c) Anti-Agglomerant Benchmarks at Interfacial and Macroscopic Length Scales

Clathrate hydrates are crystalline inclusion compounds which can form in subsea flowlines and lead to the formation of blockages. To mitigate this risk, thermodynamic hydrate inhibitors (THI), such as monoethylene glycol, are added to shift the pipeline operating pressures out of the hydrate stability region. As the production of oil and gas moves into deepwater, the required length of subsea tiebacks will increase significantly. In such operating scenarios, there is a increase in the driving force for hydrate formation, and more THI is required to fully suppress hydrate formation. To maintain the viability of deepwater assets, alternative hydrate remediation technologies must be benchmarked and validated at the benchtop and pilot scale. In the present work, we have investigated and benchmarked industrial anti-agglomerant (AA) chemicals using a micromechanical force apparatus. AAs are surfactants that target the hydrate particle surface, resulting in a non-aggregating and non-depositing hydrate-in-oil slurry. This work presents the first quantitative measurements of AA adsorption on to the hydrate interface for both first and current-generation industrial AAs. We observe that the current generation AA is a more powerful surfactant, but may be further improved by increasing its selectivity for the hydrate-oil interface. The cohesive force results were up-scaled using a high pressure rheometer, which demonstrated that the AA provided a beneficial reduction in slurry viscosity and strongly affected the hydrate crystal growth rate.