An experimental study on flow and heat transfer characteristics of binary hydrate slurries in a horizontal tube

Fluid flow and heat transfer characteristics of two kinds of binary hydrate slurries CO2-TBAB and CO2-THF in a horizontal tube are investigated experimentally. It is found that CO2-TBAB hydrate slurry shows Herschel-Bulkley (H-B) fluid characteristics at low flow velocity (< 0.35 m/s) and as a dilatants fluid at high flow velocity (> 0.45 m/s). On the other hand, CO2-THF hydrate slurry exhibits dilatant fluid properties in the flow velocity range of 0.1-0.8 m/s. Moreover, heat transfer characteristics of CO2-TBAB slurry are studied at different TBAB initial concentrations, flow velocities and heating powers. The local convective heat transfer coefficient decreases in the slurry region and then increases in the aqueous solution region. The hydrate slurry produced with 15 wt% initial concentration of TBAB shows a longer slurry region and a shorter solution region. The local convective heat transfer coefficient of CO2-TBAB hydrate slurry with 5 wt% TBAB is in a range of 4413-5397 W/m(2)K and its phase change zone is at a temperature of 12-14 degrees C.