Rheological Properties of CO₂ Hydrate Slurry Flow in the Presence of Additives

Abstract

This work investigates the flow properties of CO2 hydrate slurry in dynamic loop in the presence of additives (surfactants, antiagglomerants) for use as two-phase secondary refrigerant. To be considered as suitable for refrigeration systems, the use of hydrate slurries must overcome instability phenomena such as hydrate particle agglomeration. The additives were employed in the present work to prevent this phenomena, and thus to improve the stability and the homogeneity of the fluid. A multicriterion approach was used to select additive and to define the optimal operating conditions for its use. The selected additive was an EO/PO block copolymer. The flow properties of CO2 hydrate slurry in aqueous media in the presence of this additive were then measured in an experimental loop. It was possible to model the rheological behavior of the CO2 hydrate slurry in the presence of EO/PO block copolymer by an Newtonian-type equation. The present results were compared to previous results obtained without additive. This article provides new information on CO2-hydrate slurry rheology, which is important not only in the development of hydrate-based refrigeration systems, but also in the field of flow assurance in oil and gas pipelines or for other applications such as gas purification and storage processes using clathrate hydrates.

Rheological study on CO2 hydrate slurries for secondary refrigeration

“…Depending on the chosen equipment, the study phase (aqueous, organic or with additives) and the method, diverse behaviours of hydrate slurries have been found. In previous works, CO 2 hydrate slurries have been studied in aqueous phase [3][4][5][6][7]. HC hydrate slurries are usually studied in an organic phase [8][9][10][11][12][13][14][15][16][17][18][19].…”

“…Oyama et al [3] have characterized the dynamic viscosity of CO 2 hydrate slurries in aqueous phase as increasing before nucleation starts and then decreasing. In 2008, Delahaye et al [4] have performed rheological study of CO 2 hydrate slurries in aqueous phase using the capillary viscometer method by which they have defined the slurries' behaviour as Ostwald-de Waele shear thickening, Hershel-Bulkley shear thinning and with an apparent viscosity from 4 to 42 mPa s. A few years later, Jerbi et al [5] tested CO 2 hydrate slurries in a different system and described the fluid's behaviour as Ostwald-de Waele and shear thinning.…”

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

“…Ice slurries are the most common solideliquid fluids but their industrial applications (Guilpart et al, 2006) requires mechanical processes, as scraping or brushing surface exchangers, which increase energy losses (Schalbart et al, 2010). Gas hydrate slurries composed of a suspension of hydrate crystals in aqueous solution can also be used as secondary refrigerants (Fukushima et al, 1999) and can be produced by gas injection without mechanical processes (Fournaison et al, 2004;Jerbi et al, 2010;Delahaye et al, 2011;Jerbi et al, 2013). Clathrate hydrates are crystalline compounds formed from cages of water molecules.…”

Kinetics of Cyclopentane Hydrate Formation: An Interfacial Rheology Study

“…air conditioners and refrigerators) [6,[78][79][80][81][82][83]. Secondary refrigerants are used to transfer heat from the substance being cooled to a heat exchanger where the heat is absorbed by a primary refrigerant.…”

“…Due to its high latent heat and thermodynamic stability above ice melting point (0 o C), hydrate slurry superimposes itself over some currently used methods: aqueous solutions and ice slurry. However, problems involving hydrate agglomeration in the device are common and jeopardizes its usage [78].…”