Improvement of acid treatment with the sintanol preparation after hydro-sand blasting of wells in the conditions of ANK «Bashneft»

A sandblasting hammer is lowered into the well, setting against the selected processing interval, and hydraulic clamps are necessary for the rig to be held firmly. The displacement of the latter eliminates the possibility of selective processing. After the usual sandblasting and flushing the well from sand, without changing the position of the perforator, an acid solution is pumped into the pipes, which, entering the channel formed, is filtered through its walls into the treated section of the formation. The part of the acid that, after the end of the treatment, has accumulated in the wellbore, is forced into the reservoir by the squeezing fluid through the annular space. Increase the acid depletion time, i.e. slow down the reaction rate by adding special reagents to the solution. So, a syntanol DS-10 TU 2483-016-71150986-2012 (a non-ionic surfactant and is intended for use as an effective surfactant) is a very effective reaction rate reducer. Adding it in an amount of 0.5% (by weight of the volume of the solution) can reduce the reaction rate by 2.7 times. Keywords: speed; reaction; syntanol; processing; pressure.

Effect of ammonia and water molecule on OH + CH3OH reaction under tropospheric condition

The rate coefficients for OH + CH3OH and OH + CH3OH (+ X) (X = NH3, H2O) reactions were calculated using microcanonical, and canonical variational transition state theory (CVT) between 200 and 400 K based on potential energy surface constructed using CCSD(T)//M06-2X/6-311++G(3df,3pd). The results show that OH + CH3OH is dominated by the hydrogen atoms abstraction from CH3 position in both free and ammonia/water catalyzed ones. This result is in consistent with previous experimental and theoretical studies. The calculated rate coefficient for the OH + CH3OH (8.8 × 10−13 cm3 molecule−1 s−1), for OH + CH3OH (+ NH3) [1.9 × 10−21 cm3 molecule−1 s−1] and for OH + CH3OH (+ H2O) [8.1 × 10−16 cm3 molecule−1 s−1] at 300 K. The rate coefficient is at least 8 order magnitude [for OH + CH3OH(+ NH3) reaction] and 3 orders magnitude [OH + CH3OH (+ H2O)] are smaller than free OH + CH3OH reaction. Our calculations predict that the catalytic effect of single ammonia and water molecule on OH + CH3OH reaction has no effect under tropospheric conditions because the dominated ammonia and water-assisted reaction depends on ammonia and water concentration, respectively. As a result, the total effective reaction rate coefficients are smaller. The current study provides a comprehensive example of how basic and neutral catalysts effect the most important atmospheric prototype alcohol reactions.

Influence of the formation of short-chain olefins by manganese/cobalt-catalyzed Fischer–Tropsch synthesis on the selectivity and effective reaction rate

For cobalt catalysts with manganese as promoter, a high selectivity to olefins is found in low-temperature FTS over small catalyst particles. With industrial scale particles severe changes in selectivity and an increase of reaction rate is found.

Diffusion and Heterogeneous Reaction in Porous Media: The Macroscale Model Revisited

Diffusion and reaction in porous media have been studied extensively due to the wide range of applications in which this transport phenomenon is involved. In particular, in chemical reactor engineering, reactive mass transfer is crucial to understand the performance of porous catalyst particles immersed in chemical reactors. Due to the disparity of characteristic lengths between the pores and the porous particles, this type of process is usually modeled by means of effective-medium equations, in which the solid and fluid phases are conceived as a pseudo-continuum. For conditions in which the pore-scale Thiele modulus (or Kinetic number) is much smaller than unity, it is reasonable to assume that the effective diffusivity involved in the effective-medium model is only a function of the porous medium geometry. However, a long debate has existed in the literature concerning the extensive use of this assumption for situations in which the Kinetic Number does not satisfy the above mentioned constraint. In addition, the functionality of the effective reaction rate coefficient with the Kinetic number has not been sufficiently studied. In this work we address these issues by means of the volume averaging method. Our analysis is focused on cases in which the Kinetic number can reach values up to 1. Interestingly, for this particular condition, the use of the intrinsic diffusivity tensor is justified. In addition, by means of Maclaurin series expansions, the effective reaction rate coefficient is shown to be acceptably approximated as a first-order function. These two conclusions for the effective medium coefficients constitute the major contributions from this work. In addition, the predictions from the upscaled model are validated by comparison with direct numerical simulations under steady and transient conditions.

A Numerical Study of the Unsteady Effects of Droplet Evaporation and Ignition in Homogeneous Environments of Fuel and Air

The transient processes of droplet heating, vaporization and ignition in a quiescent heated environment of a homogeneous mixture of air and fuel that is potentially combustible are analyzed. A system of partial differential equations that governs this hybrid diffusional-premixed processes is presented. The equations were solved numerically for an n-heptane droplet vaporizing in a homogeneous environment of methane and air. The effective reaction rate of the oxidation processes was assumed throughout to equal the sum of the reaction rates due to droplet and auxiliary fuels. The gross reaction rates used in the model for the droplet and auxiliary fuels were obtained from curve fitting of reaction rates results obtained from detailed chemical kinetics for the two fuels system. It is to be shown, for example, that the presence of an auxiliary fuel with the air in the surrounding environment of the droplet enhances the rates of the ignition/combustion processes of the droplet.

THERMAL, STABILITY OF W/C MULTILAYER FILMS

Arstract:W(15 Å)/C(15 Å), W(50 Å)/C(50 Å) and W(100 Å)/C(100 Å) periodic multilaver films were prepared by magnetron sputtering and suhsequently annealed at 980, 730 and 500°C. The changes of layered and crystal structures were studied by x-ray diffraction. The results depended largely on the thickness of W layers and their initial crystal struictures of W. The kinds of transformations are classified into two types: one is the non-reacting type in the case of multilayers having the thinner W layers like W(15 Å)/C(15 Å), in which the crystallization of W layers prevails over the reactions between W and C layers; the other, the reacting type in the multilayers having thicker W layers like W(50 Å)/C(50 Å) and W(100 Å)/C(100 Å), in which reactions Prevail over crystallization. A tentative model in which the effective reaction rate between amorphous–W and amornhous–C is much smaller than that of crystalline-W(beta phase) and amorphous-C is proposed to explain the origin of the phenomena.

Diffusion Controlled Effective Reaction Rate for a Surface Reaction with Orientational Selectivity

The influence of the orientational selectivity of a chemical reaction on the diffusion controlled effective reaction rate is investigated theoretically for the following situation: Nonspherical molecules with random orientation are put into a chemically inert solution at a plane which is a certain distance away from the parallel reaction plane. The reaction frequency at the surface shall depend on the orientation of the figure axis of a molecule relative to the normal of the reaction plane. With a special choice for the orientational dependence of the surface reaction, a continued fraction expansion is derived for the diffusion controlled effective reaction rate. This quantity is discussed and displayed graphically as function of the relevant parameters.