Clathrate hydrate is a crystalline compound that encage guest molecules such as small hydrocarbons or organic molecules inside the cages of hydrogen-bonded water molecules. To control the nucleation and growth of clathrate hydrates, this thesis intensively investigated the macroscopic and microscopic behaviors at the nanoparticle stabilized water-oil interface. By providing fundamental basis for performance improvement and application into industry as well as the inhibition effects and their mechanisms, the utilization of nanoparticles at flow assurance problem was suggested. The contents of each chapters are as follows.In Chapter 2, the hydrophobic silica nanoparticles stabilized at the water-oil interface inhibited the growth of hydrate particles through the anti-adhesive effect, which operates with different mechanisms from common anti-agglomerants. In the water-in-oil type Pickering emulsion system stabilized by magnetic nanoparticles, the agglomeration between hydrate particles was prevented by the anti-adhesive effect, and the induction time for hydrate nucleation was delayed. Thus, in Chapter 3, it was confirmed that the particle-based inhibitors have dual inhibition effects of kinetic hydrate inhibitors and anti-agglomerants. By identifying the conditions for hydrate promotion according to the emulsion properties and enhancing the recovery of inhibitors through boot drum and co-solvents, the application into the offshore platforms was suggested. In Chapter 4, the molecular dynamic simulations showed that the nanoparticle layer at the water-oil interface forms an amorphous solid-like layer that may act as a nucleation seed, while inhibiting the dissolution of the gaseous guest molecules into the aqueous phase. Particle-based inhibitors block the water molecules from heterogeneous nucleation sites as well as guest molecules, but it was investigated that they can also contribute to hydrate promotion by themselves, suggesting optimization objects for improving inhibition performances.
클러스레이트 하이드레이트는 물 분자의 수소결합 네트워크로 이루어진 동공 내부에 객체 분자들을 포접하는 결정질 화합물이다. 본 학위논문에서는 나노 입자가 안정화된 물-기름 계면에서의 거시적, 미시적 거동 현상을 집중적으로 분석함으로써 하이드레이트의 결정화 및 성장을 제어하고자 했다. 입자형 억제제의 억제 메커니즘과 성능 향상 및 실용화를 위한 기초자료를 제공함으로써, 입자를 활용한 심해저 수송관 내부의 유체흐름 안정성 확보 방안을 제시했으며, 각 장의 내용은 다음과 같다.제 2장에서는 나노 입자가 가지는 하이드레이트-수용액간 항 점착 효과에 의해 하이드레이트의 추가적인 성장이 저해됨을 규명했다. 자성 나노 입자에 의해 안정화된 에멀전 시스템에서 항 점착 효과에 의한 응집 억제뿐만 아니라 결정화 역시 지연되었으며, 이를 통해 제 3장에서는 동역학적 저해제 및 응집 억제제로서의 이중 억제 효과를 확인했다. 또한 에멀전의 성상에 따른 결정화 촉진 조건을 파악하고 부트 드럼 및 공용매를 통해 회수율을 증가시킴으로써 실용화 방안을 제시했다. 제 4장에서는 분자 동역학 시뮬레이션을 통해 나노 입자가 객체 분자의 용해를 저해함과 동시에 결정화 종자로 작용하는 비정질의 유사 고체 층을 형성시키는 것을 규명했으며, 이는 성능 향상을 위한 최적화 대상을 제시한다.
