Heat transfer measurements in stirred, cylindrical cells containing ethylene oxide (EO) and tetra hydro furan (THF) hydrate – water solutions at temperatures between 1 – 4 °C as function of amounts and volume of hydrates present in the solutions.

Abstract

It is believed that heat transfer plays a major role in hydrate formation, and is also dependent on the hydrate concentration. Heat transfer during hydrate growth is an important process, which deserves a great depth of study.

The aim of this present work is to analyze the heat transfer properties of hydrate – water suspensions/slurries as function of hydrate concentration in the slurry. Ethylene oxide (EO) and tetrahydrofuran (THF) was used as hydrate formers. Both of these components are completely soluble in water and the amount of hydrates formed was controlled by the given stoichiometric concentration of EO or THF added to the water prior to hydrate formation. Heat transfer properties of the EO and THF hydrate suspensions were measured in the temperature region between 1 and 4 °C.

The analytical model and program used, is based on the former studies of Meindinyo. The program can be used to predict and validate the heat transfer coefficient of the aqueous phase/solution present in the cell interior through temperature responses during controlled heating and cooling cycles.

The stability of the hydrates during the test was dependent on the hydrate equilibrium properties of the system at the given concentration of EO and THF in the water phase. For concentrations less than 40 % of stoichiometric concentration the THF and EO hydrates dissociated during the test sequence between 1 and 4 °C. The heat transfer coefficient of hydrate suspension (hI) showed a general dependence on amount of hydrate in slurry. hI decreased with an increase in amount of hydrate in hydrate suspension. Analysis was also carried the effects of stirring rate, and cell volume on the heat transfer behavior.