Chord length distributions measurements during crystallization and agglomeration of gas hydrate in a water-in-oil emulsion: Simulation and experimentation

Abstract

International audienceThe formation of gas hydrates from water-in-oil emulsion was investigated on two different flow loops: a laboratory scale flow loop (Archimede flow loop: 30 m long, and 1 cm diameter, St-Etienne School of Mines) and a pilot scale flow loop (Lyre flow loop: 150 m long, 5 cm diameter, IFP Solaize). Both flow loops are equipped with a focused beam reflectance measurement (FBRM) probe for in situ particle size analysis. These FBRM probes were used to monitor chord length distribution (CLD) during the crystallization process of water-in-oil emulsions into gas hydrate slurries. When water droplets crystallize into hydrate particles, an agglomeration phenomenon is evidenced by pressure drop measurements. This agglomeration phenomenon is also detected by the FBRM probe and is highlighted by a sharp change in the mean chord length and a spread of the CLD to larger chord length. In order to better interpret the chord length distribution measurements, a modelling work has been made. This paper gives a description of the algorithm used for building 3D fractal aggregates and simulating CLD measurements on them. Aggregates are constructed from a monodisperse spherical particle. The influence of different parameters (fractal dimension, number of particles in the aggregate, diameter of primary particles) on the simulated CLD is also discussed. Some comparisons between experimental and simulated CLD are finally used to describe the physical properties of aggregates during an experiment

An investigation on gas hydrate formation and slurry viscosity in the presence of wax crystals

“…An independent device with METTLER TOLEDO FBRM ® D600 probe (focused beam reflectance method) was used to obtain the chord length distribution (CLD) of water droplets in the emulsions . CLD is just a straight line between two points on the edge of a droplet/particle scanned by a highly focused laser beam through the sapphire window of the probe, which can be converted to the particle‐size distribution (PSD) of droplets/particles …”

Dynamics of hydrate formation and deposition under pseudo multiphase flow

“…[40][41][42] Once the hydrate particles are formed, the strong interaction between the hydrate particles cause them to form fractal-like hydrate aggregates. [43][44][45] When larger hydrate chunks are formed, water is absorbed and trapped in the hydrate mass. As the hydrate particles increase in size and amount, the oscillation of the cell is insufficient to keep the larger hydrate particles suspended in the oil phase.…”

Particle size distribution of TBPB hydrates by focused beam reflectance measurement (FBRM) for secondary refrigeration application

“…Among them, Focused Beam Reflectance Measurement (FBRM) was found to be a suitable method with the advantage to be not destructive (Clarke and Bishnoi, 2005;Turner et al, 2005;Greaves et al, 2008b;Turner et al, 2009aTurner et al, , 2009bLeba et al, 2010;Al-Otaibi et al, 2011;Cameirao et al, 2012). FBRM is an in-situ method for counting and sizing particles and aggregates applied in various fields such as crystallization (Zhao et al, 2012) and food technology (Arellano et al, 2012;Ndoye et al, 2013).…”