Drainage mechanism

There are several drainage mechanisms are employed at petroleum and related facilities - surface runoff or grading, spill containment (diking), gravity sewers (oily water and sanitary) and pressurized sewer mains, and lift station collection sumps. 

Mechanism of Action An intratracheal respiratory inhalant that splits the linkage of mucoproteins, reducingtheviscosityof pulmonary secretions.Tiierapeutic Effect Facilitates the removal of pulmonary secretions by coughing, postural drainage, mechanical means. Protects against acetaminophen overdose-induced hepatotoxicity. Pharmacokinetics Protein binding 83% (injection). Rapidly and extensively metabolized in liver. Deacetylated by the liver to cysteine and subsequently metabolized. Excreted in urine. Half-life 5.6 hr (injection). 

When two emulsion drops or foam bubbles approach each other, they hydrodynamically interact which generally results in the formation of a dimple [10,11]. After the dimple moves out, a thick lamella with parallel interfaces forms. If the continuous phase (i.e., the film phase) contains only surface active components at relatively low concentrations (not more than a few times their critical micellar concentration), the thick lamella thins on continually (see Fig. 6, left side). During continuous thinning, the film generally reaches a critical thickness where it either ruptures or black spots appear in it and then, by the expansion of these black spots, it transforms into a very thin film, which is either a common black (10-30 nm) or a Newton black film (5-10 nm). The thickness of the common black film depends on the capillary pressure and salt concentration [8]. This film drainage mechanism has been studied by several researchers [8,10-12] and it has been found that the classical DLVO theory of dispersion stability [13,14] can be qualitatively applied to it by taking into account the electrostatic, van der Waals and steric interactions between the film interfaces [8]. 

Arriola (8) and Ni (5) have observed a second mechanism for snap off in strongly constricted square capillaries. At low liquid flow rates, a bubble is trapped in the converging section of the constriction and liquid flows past the bubble. As liquid flow rate increases, waves developed in the film profile and at some critical liquid flow rate these oscillations become unstable and bubbles snap off. In these experiments, the bubble front is located upstream of the constriction neck. Therefore, no driving force for the drainage mechanism exists. Bubbles formed by this mechanism are produced at a high rate and have a radius on the order of the constriction neck. No attempt has previously been made to model snap-off rate by this mechanism in noncircular constrictions. 

Increased surface viscosity Increased film thickness Gibbs-Marangoni effect Net surface charge Residual tertiary structure Gravitational drainage Capillary pressure drainage Mechanical shock Film permeability Surface active molecules... 

The above discussion shows how downhole hydrodynamic studies of the well can reveal the drainage mechanism active in the reservoirs containing viscous-elastic petroleums of non-Newtonian type. The following conclusions can be made in iMs regard ... 

All experiments were conducted at a temperature of 30°C, corresponding to the temperature in the oil-bearing formation at Zybza field. The reservoir model was laid in a horizontal position in order to exclude the influence of gravity on the oil drainage mechanism. 

At high surfactant concentrations (above the c.m.c.), micelles of ionic or nonionic surfactants can produce organised molecular structures within the liquid film [21, 22]. This will provide an additional contribution to the disjoining pressure. Thinning of the film occurs through a stepwise drainage mechanism, referred to as... 

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