-
Application of Markov Theoretical Model in Predicting Risk Severity and Exposure Levels of Workers in the Oil and Gas Sector
Okwu Modestus Okechukwu,
Thaddeus C. Nwaoha,
Ombor Garrick
Issue:
Volume 4, Issue 3, June 2016
Pages:
103-108
Received:
9 May 2016
Accepted:
21 May 2016
Published:
6 June 2016
Abstract: In this research, Markov theoretical approach (MTA) was used to forecast the severity of risk workers were exposed to in the oil and gas industry and to determine the average period of time it would take workers to get exposed to menace of less severity and the possibility of transiting to a state where risk is high. The perils were classified into four states which include: catastrophic, critical, marginal and negligible. A solution procedure for addressing industrial hazards was developed from Markov. Fifty (50) workers in Warri Refining and Petrochemical Company (WRPC) were randomly selected for the purpose of questionnaire administration. Analysis of the data was carried out using QM software. The results showed that 56.66% of workers in marginal state would likely move to catastrophic state, while 43.34% of workers in marginal state would probably transit to critical state. Also 41.32% of workers in negligible state would move to a catastrophic state, while 58.68% of workers in negligible state would likely move to critical state within an average period of 2 to 3 years. It is therefore recommended that provision of personal protective equipment and appropriate healthcare facilities be made, risk assessment of all workers be continuously carried out; workers must be properly trained on regular basis and the enforcement and strengthening of existing legislation effectively carried out to dispel these hazards.
Abstract: In this research, Markov theoretical approach (MTA) was used to forecast the severity of risk workers were exposed to in the oil and gas industry and to determine the average period of time it would take workers to get exposed to menace of less severity and the possibility of transiting to a state where risk is high. The perils were classified into...
Show More
-
Investigation of Effects of Tool Geometry Parameters on Cutting Forces, Temperature and Tool Wear in Turning Using Finite Element Method and Taguchi’s Technique
Le Hieu Giang,
Mai Duc Dai,
Pham Minh Duc
Issue:
Volume 4, Issue 3, June 2016
Pages:
109-114
Received:
4 May 2016
Accepted:
20 May 2016
Published:
6 June 2016
Abstract: Turning is one of the most widely metal cutting methods. Machines, tool geometry and machining parameters are the main factors influencing machining quality and efficiency. So there is a lot of research on it. This paper studies on the influence of the geometrical parameters of the tool including: back rake angle (BR), side rake angle (SR) and side cutting-edge angle (SCEA) on cutting forces, temperature and tool wear in turning using FEM (by Deform 3D finite element simulation software) and Taguchi’s technique (by Minitab16 statistical software) is used to design the experiment and to analyze output quality characteristics from simulation results. And the optimum tool geometry parameters are given.
Abstract: Turning is one of the most widely metal cutting methods. Machines, tool geometry and machining parameters are the main factors influencing machining quality and efficiency. So there is a lot of research on it. This paper studies on the influence of the geometrical parameters of the tool including: back rake angle (BR), side rake angle (SR) and side...
Show More
-
Estimating On-Bottom Stability of Offshore Pipelines in Shallow Waters of the Gulf of Guinea
Ogbonda Douglas Chukwu,
Chinwuba Victor Ossia,
C. O. Akhigbemidu
Issue:
Volume 4, Issue 3, June 2016
Pages:
115-122
Received:
14 May 2016
Accepted:
24 May 2016
Published:
13 June 2016
Abstract: Pre-installation Stability analyses of pipelines are required to prevent lateral and upheaval buckling in service. In this study, the hydrodynamic forces associated with an offshore pipeline is analyzed, thereby determining limiting steel wall-thickness and submerged weight necessary to prevent collapse and propagation buckling, contain pressure and ensure on-bottom stability. Relevant design equations, Codes and Procedures were integrated to create a comprehensive platform for analyzing lift, drag and inertia forces acting on submerged pipelines. Hence, a user friendly template with multiple design settings has been developed with MathCAD® for on-bottom stability analyses. The analysis tool is based on the absolute lateral stability method in DNV RP F109. A case study of Φ762 mm x 34 km pipeline to be installed Offshore Escravos, Gulf of Guinea is simulated and analyzed using the design tool developed. Pipeline behavior under different environmental and pipeline conditions such as water depth, wave height, steel and concrete thickness were investigated. The results showed that concrete and steel wall thicknesses are the most critical parameters in the on-bottom stability of offshore pipelines. With a determined optimal wall thickness of 20.6mm, concrete thicknesses of 78.796 mm, 61.386 mm, 53.043 mm and 42.58 mm corresponding to 5 m, 10 m, 15 m and 20 m water depths, respectively were obtained. Also, the results showed that for pipes OD > Φ32.5 in (Φ825.5 mm) alternative stability methods may be required as the necessary concrete thickness may exceed allowable limits.
Abstract: Pre-installation Stability analyses of pipelines are required to prevent lateral and upheaval buckling in service. In this study, the hydrodynamic forces associated with an offshore pipeline is analyzed, thereby determining limiting steel wall-thickness and submerged weight necessary to prevent collapse and propagation buckling, contain pressure an...
Show More
-
A Study on Energy Optimization of Heat Exchangers in a Gasification System
Le Minh Nhut,
Young-Sub Moon,
Youn Cheol Park
Issue:
Volume 4, Issue 3, June 2016
Pages:
123-129
Received:
16 May 2016
Accepted:
27 May 2016
Published:
13 June 2016
Abstract: The objective of this research is the optimization of energy parameters such as the temperature and flow rate of the fluid in heat exchangers in the gasification system in order to increase the recovery rate of energy in the system. A mathematical model of these heat exchangers is developed to predict their operating performance under the specified gasification system. The optimal flow rate and temperature of the fluid in the heat exchanger based on the effectiveness - number of transfer units(NTU) method is investigated. The result of the simulation shows that the optimal mass flow rate and temperature of the high pressure (HP) boiler feed water are determined at 175,907 kg/h and 110°C, respectively, while the optimal mass flow rate and temperature of high pressure saturated steam of boiler are determined at 238,430 kg/h, 290.5°C, respectively. At these values, the total heat amount obtained at these heat exchangers is highest with 169 MW. Besides, the total heat amount obtained at heat exchangers could be increased by 4.61% (7.8 MW) when sixty percent of the heat release amount from air cooler (12.78 MW) is used.
Abstract: The objective of this research is the optimization of energy parameters such as the temperature and flow rate of the fluid in heat exchangers in the gasification system in order to increase the recovery rate of energy in the system. A mathematical model of these heat exchangers is developed to predict their operating performance under the specified...
Show More
-
Deduction of Reliability Parameter for Spherical Roller Bearing
Issue:
Volume 4, Issue 3, June 2016
Pages:
130-135
Received:
10 May 2016
Accepted:
28 May 2016
Published:
18 June 2016
Abstract: To establish the reliability assessment technology of spherical roller bearing, we performed the major failure analysis, and then produced the reliability parameters for spherical roller bearing. As a first step, we made out the failure analysis data of roller bearing. And then, we decided the reliability parameters of spherical roller bearing by using of MINITAB software. Then we verified propriety the reliability parameters by comparison of pre-performed test results and MINITAB analysis. In this paper, we proposed a method of the reliability assessment technology of spherical bearing, and showed the reliability parameters of roller bearing by use of 8-samples spherical roller bearing. And also, we presented the useful reliability parameters for roller bearing test, which are produced by MINITAB analysis and marking of Weibull probability paper using the measured some life points, and also verified the propriety of reliability parameters by some kinds of complex tests.
Abstract: To establish the reliability assessment technology of spherical roller bearing, we performed the major failure analysis, and then produced the reliability parameters for spherical roller bearing. As a first step, we made out the failure analysis data of roller bearing. And then, we decided the reliability parameters of spherical roller bearing by u...
Show More
