Search

The present paper proposes ways to reduce energy consumption during naphtha isomerization and catalytic reforming by optimizing the recovery heat exchange of the feed preparation unit using pinch analysis. A pinch analysis procedure based on heat flux integration was carried out in three stages. At the first stage, information on the technological and energy characteristics of the unit was collected and studied. At the second stage, options for improving the energy efficiency of the unit were determined. At the third stage, a detailed study of technical solutions for optimizing the flow scheme of recovery heat exchange was performed along with an economic justification. Proposed options for modernizing the existing industrial unit are based on the set of positive values for economic indicators and criteria of the program for improving the operational efficiency. The presented heat exchange system layouts can be used in the design and modernization of secondary naphtha distillation units at oil and gas refineries. [ABSTRACT FROM AUTHOR]

In this article, the propagation of the detonation of a propane-butane mixture with oxygen is investigated in a channel of constant cross section with a diameter smaller than the critical one for detonation propagation. The ignition of the mixture is performed in a precombustion chamber. The entering of the flame front into the narrow channel causes the development of detonation in the channel. In this work the profiles of the pressure at the entry into the channel and the average velocities of propagation of the flame front for different sections of the channel are presented. The values of the velocity correspond to the values of the Chapman-Jouguet velocity. In this work various scenarios of the propagation of detonation depending on the size of the precombustion chamber have been investigated. [ABSTRACT FROM AUTHOR]

Thin magnetic multilayered films containing FePt have attracted a lot of attention recently due to their possible usage in ultra-high density magnetic storage. Although structure defects play a dramatic role in the magnetization process and influence magnetic properties in general this dependence have not been studied thoroughly. The main aim of this work was to perform theoretical investigation of the magnetic properties of FePt and Fe/FePt thin films with high coercivity with respect to the structure defects such as anisotropy constant, magnetization saturation, exchange constant fluctuations, and easy axis deviation. For selected defect patterns, the coercive field dependence on layer thicknesses was analysed. Numerical study of the bilayer with hard magnetic layer having the planar anisotropy was carried on using micromagnetic calculations. Values of layers thickness have been found optimal for perspective applications, the dependence of the hysteresis loop shape upon the magnetization process has been shown and analysed. © 2014 AIP Publishing LLC. [ABSTRACT FROM AUTHOR]

The results of an experimental study of three cases of the interaction of a shock wave with screens made of an easily destructible material are given. The dependence of the coefficient of attenuation on the thickness and location of the screen is obtained. [ABSTRACT FROM AUTHOR]

Experimental results are presented for the impact on blockage by airflow exhausted from a highpressure vessel and containing micron-sized solid particles. The static and the dynamic pressures on the blockage at different initial jet parameters are determined. The degree of the pressure increase on the blockage depending on the initial pressure in the vessel and the solid phase concentration is determined. The pressure of the flow with the powder on the blockage may be up to three times as much as the same in pure gas. [ABSTRACT FROM AUTHOR]

The article presents a study which determines the reflected shock wave interaction's parameter with the deformed blockage. And the impact of the shock wave in a channel on blockages made of variety of materials. The study employed two test sections such as the TS1 and TS2 that were installed in the low pressure chamber (LPC). Results revealed that the shock wave attenuation is bigger upon an explosion of fuel gases inside the LPC with a thin granular material or sand wall.