Dissolution Characteristics of Hydrophobically Associating Polyacrylamide in Stirred Tanks

Enhanced oil recovery(EOR)by means of polymer flooding is an important technology for the strategic development of offshore oilfields in China.Hydrophobically associating polyacrylamide(HAPAM)has been recently proposed as a new flooding agent.The solubility of HAPAM is low,which is the bottleneck for further improving the oil recovery through polymer flooding in offshore oilfield.Stirred tanks have been used on offshore platforms to enhance HAPAM dissolving.But there is little literature on the study of HAPAM dissolving characteristics in stirred tanks.In this paper,effects of temperature,salinity,stirring speed,impeller type and stirring method on the dissolution of HAPAM are reported.The experimental results manifest that the dissolving rate of HAPAM increases with temperature and stirring speed,but the viscosity of the polymer solution decreases.There is an optimal range of salinity for polymer dissolving.Combining the operation mode of up-pumping with varying stirring speed,hydrofoil impeller can accelerate the dissolution of HAPAM and maintain a high solution viscosity.

Computational fluid dynamics simulation and experimental analysis of ultrafine powder suspension

The suspension characteristics of ultrafine powder slurry in the stirred vessel were simulated by using computational fluid dynamics.The results show that the Rushton disk turbine impeller is more conducive to maintaining suspended homogeneity and circulation of slurry compared with the pitch blade turbine pumping up impeller and the pitch blade turbine pumping down impeller.And the increase in stirring speed enhances turbulent fluctuation and anisotropic velocity of the fluid at the cost of more power consumption,which improves dispersibility and suspensibility of the particles.Meanwhile,the change of impeller clearance has a weak influence on the flow pattern,and the impeller clearance of 0.32T(T is the diameter of the bottom of the reactor)can achieve better dispersivity and suspensibility of the particles with lower power consumption and larger axial velocity.The experiments of surface coating modification of ultrafine titanium dioxide(TiO2)were carried out under the same conditions for those of the simulation system.The surface film morphology and photocatalytic properties of the modified TiO2 were analyzed,and the obtained data are well consistent with the simulation results.