Purpose Algeria occupies an important place in all of the oil-producing countries. However, in recent years, industrial facilities have experienced a rapid increase in the number of major industrial accidents and calamities, where fires and explosions have caused impacts and severe effects on people, property and the environment. Therefore, this paper aims to analyze the risks involved and assess the performance of the technical barriers at the thermo-hydraulic level of facilities at the level of the refinery of Skikda. Design/methodology/approach The most effective methods in this field of activity are the systematic analyses of deviations or failures. As working tools, hazard and operability (HAZOP) method and fault tree analysis (FTA) were used to identify the various possible risks that could lead to undesirable phenomena, with the Topping unit. Using this type of analysis, it is possible to understand what the most risky process steps are and, where appropriate, to propose appropriate corrective and preventive measures. HAZOP is dedicated to the analysis of the risks of thermo-hydraulic systems and to control drift parameters such as pressure, temperature and flow. Unfortunately, with its limitations to the detection of leaks, the authors completed the study by FTA, working with a predetermined set of process parameters associated with system operation (compression, temperature, flow, etc.). Each of these parameters are combined with a series of possible potential deviations (too much, little, inverse, etc). For each analyzed equipment, the relevant parameters are selected and combined with the relevant deviations. For each parameter of the deviant process, the causes and consequences are determined. Findings The combination of these two methods has allowed to highlight the various possible risks that could lead to undesirable phenomena, to respond to industrial expectations or even to manage the operation process safely. Thus, it enabled the authors to detect the weaknesses of the process. This allowed the authors to reinforce the technical safety barriers of the functional links of the process and propose appropriate, corrective and preventive measures. Originality/value The work intends to reflect the real situation in which companies face risks. The originality of the work is represented by the combination of two methods: HAZOP and the FTA. This association allowed the authors to identify areas of weakness to set priorities for action by the company, through organizational, technical and human solutions, while engaging in a process of continuous improvement.

Purpose This paper aims to determine the rational operating regime of a rotary percussive drilling machine under optimal conditions. Design/methodology/approach An orthogonal array of Taguchi, signal-to-noise (S/N) ratio, ANOVA Pareto analysis and regression analysis are used to investigate the effect of drilling operational factors on the penetration rate. A series of experiments based on orthogonal arrays L27 was carried out, and the results were collected and analyzed using the statistical software Minitab. Findings The statistical analysis (ANOVA Pareto) of the results showed that among all setting parameters, air pressure is the most essential element that affects the penetration rate. The rational operating regime of the rotary percussive drilling machine was determined with optimum air pressure values of 17 bar (Level 3), rotation speed of 60 rpm (Level 3) and a thrust of 825 kgf (Level 2), which maximize the penetration rate. A quadratic regression model was developed for the penetration rate. The predicted values are compared with the experimental data and are considered to be in good agreement. Originality/value The study uses the orthogonal array of Taguchi, S/N ratio, ANOVA Pareto analysis and regression analysis to investigate the effect of drilling operational factors on the penetration rate.

Shunt active power filter based on multilevel inverter is used to compensate the power factor and to delete the harmonics. This one permits to reduce the inverse voltages applied to the filter switches and their switching frequencies. Nevertheless, the high number of used switches requires a complicated controller and increases the switching losses; where the necessity of finding another resolution system. In this work a new topology of multilevel inverter is proposed as a shunt active power filter using two IGBT transistors in series of opposite sense meticulously controlled by a parallel control algorithm, with the concept of reduced number of six switches which are able to create five levels of the output voltage. This system substute the classical system of eight switches. The harmonic currents identification is carried out using the instantaneous active and reactive power method. The simulation is performed using Matlab/Simulink. The obtained results show that the filtering performances are well enhanced.

This paper presents a modeling and control of new model in a spatial coordinates (x, y, z), from this structures we choose: regular pyramid of a square basis manipulated by five cables and eight cables for a cubic shape. The main objective of this work is to integrate the axe (z) on the horizontal plane (x, y) i-e the plan 3D. This last their intervention especially when we obliged to transfer the end effector from point to point, for that we used the direct and inverse geometric model to study and simulate the end effector position of the robot with five and eight cables. A graphical user interface has been implemented in order to visualizing the position of the robot. Secondly, we present the desired path and determination the tensions and cables lengths of kinematic model required to follow spiral trajectory. At the end, we study the response of our systems in closed loop with a Proportional-Integrated-Derivative (PID) using MATLAB/Simulink which used to verify the performance of the controller.

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