An Experimental Study on Efficient Demulsification for Produced Emulsion in Alkaline/Surfactant/Polymer Flooding

Tertiary oil recovery technologies, exampled as alkaline/surfactant/polymer (ASP) flooding, can enhance oil recovery (EOR) as an important oil displacement technology noteworthy in the present oilfields. However, it is the fact that the produced emulsion droplets have strong electronegativity, which will lead to the destabilization of electric field and affect the dehydration effect in the process of electric dehydration. This paper innovatively proposed an efficient demulsification scheme, which uses platinum chloride (PAC) as a chemical regulator to control electric field destabilization through the charge neutralization mechanism, and then introduces demulsifier to promote oil-water separation. Furthermore, the dehydration temperature, power supply mode and electric field parameters are optimized so as to achieve superior dehydration effect of ASP flooding produced liquid. The results indicate that PAC as a chemical regulator by exerting charge neutralization and electrostatic adsorption mechanism could reduce the electronegativity of the emulsified system, decrease the peak current of dehydration, shorten the duration of peak current of dehydration, improve the response performance of the electric field, and increase dehydration rate in ASP flooding dehydration process. When the demulsifier dosage is 100 to 120 mg/L, using the composite separation process with the dehydration temperature of 45 to 50 °C for the thermochemical separation stage and 60 °C in the electrochemical dehydration stage and AC-DC composite electric field or pulse electric field can achieve better dehydration effect. The investigations in this study will provide support and basis for the efficient treatment of ASP flooding produced emulsion.

Mutual Comparison Studies of Mono and Di Cations in Binary and Ternary Aqueous Electrolytes Solution at 298.15 K

Densities and viscosities of binary and ternary electrolytes solution have been determined experimentally at 298.15 K. The results obtained from density and viscosity measurement have been used to calculate apparent molar volume φv partial molar volume φov at infinite dilution, relative viscosities hrel, A and B coefficients, and free energies of activation of viscous flow of solvent Δ µ10# and solute Δ µ20. The results are discussed in terms of the dehydration effect of the weak ion-ion and strong ion-solvent interactions. The properties of these systems are discussed in terms of the charge, size, and hydrogen bonding effect.

Study on Hydrodynamics Model of Total Tailings Filling Slurry Dehydration

In order to ensure the dehydration effect of the whole tailings backfill, a dehydration model of the whole tailings backfill was established based on hydrodynamics on the basis of satisfying certain assumptions, and the theoretical solution was carried out. The control variable method is used to study the variation of dewatering capacity with dewatering depth and radius, and the applicability of the dewatering model is verified by experiments. The results show that the dewatering capacity increases with the increase of dewatering radius and decreases with the increase of dewatering depth by a quadratic polynomial. By comparing the experimental values with the theoretical ones, it is found that the variation law of the dewatering capacity with radius is the same and increases with the increase of dewatering depth. The reason is that the content of fine particles in the unclassified tailings is large and the filter hole on the branch pipe is blocked under the action of the hydrodynamic force. Therefore, the dewatering effect of the new root-like dehydration tube can be guaranteed by using the branch pipe arranged at the full height of main dewatering pipe. The dehydration model is modified by the test results to ensure the applicability.

Investigation of Multi-layered Fire Doors with Gypsum Layer Exposed to Fire

This article analyzes gypsum board dehydration effect on heat conductivity and deformation of multi-layered mechanical structures subjected to temperature changes. Specially designed structures (fire doors) consisting of steel sheets with stone wool and gypsum insulating layers in between were heated in furnace for a specified period of time of not less than 60 min. Temperature versus time curves and deformations of multi-layered structures were obtained. Experimental results were verified by numerical simulation. Experimental data was found to be in good agreement with numerical simulation results. The percent differences between door temperatures from simulation and fire test don’t exceed 9 %. This shows that thermal behavior of such multi-layered structures can be investigated numerically avoiding time-consuming and expensive fire tests. The data obtained allowed to calculate convective heat transfer coefficient of gypsum board, which was fitted into multi-layered mechanical structure. It was found that it is more advantageous to place gypsum layer in the middle of the structure rather than closer to the fire source in order to cool the structure more efficiently during fire.