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2 2018

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Power generation problems ranking using a combination of ahp and moora techniques

Emovon I., Nwaoha T. C.

Research in Logistics & Production

2018

Vol. 8, No. 2

155–-168

The inadequate electricity generation in Nigeria is the major reason for her economic woes. From the literature some of the problems affecting power generation in Nigeria are lack of policy continuity, drought, Militant activities and corruption. However the degree of impact each of the problem has on power generation varies. Therefore there a need to develop a tool that will identify critical problems such that power generation managers’ will use bulk of the meagre available resources in addressing the more critical ones. In this paper a tool which combine Multi-Objective Optimisation on the basis of Ratio Analysis (MOORA) technique with Analytical Hierarchy Process (AHP) is proposed for the prioritisation of the problems affecting power generation in Nigeria. The technique is illustrated with a numerical example developed from data from experts. From the result of the analysis, poor maintenance of power generation infrastructure, militant activities and corruption are the most critical problems hampering power infrastructure development in Nigeria. The proposed technique have been proven to be effective in prioritising power generation challenges as it produces almost completely same result with well-known mathematical techniques in literature.

Comparative analysis of the effect of vernonia amygdaline on subsea transmission pipeline

Samson N., Nwaoha T. C., Emmanuel U. O.

Journal of Mechanical and Energy Engineering

2018

Vol. 2, No 4

269--276

Subsea transmission pipelines (STP) are designed to transport liquids, gases or solid/liquid mixtures over some distances. STP are buried underground or submerged in water for transportation of natural oil and gas (O&G) products. A Vernonia amygdalina (VA) solution is prepared to act as an inhibitor. The specimens are kept in a workable state. Steps are taken to prepare each specimen. All cuts and sheared edges were ground out to prevent them from becoming sites for preferential attack. The finishing of the specimen surface with grit abrasive paper (sand paper) and rinsing of the specimens in distilled water are carried out. Then, degreasing of specimen in acetone and air-dried are carried out. Upon drying, the specimens are immediately weighed to obtain their initial weights. Twelve specimens are used for the test as follows: 6 Aluminum (Al); and 6 mild steel (MS) samples. With a 2M concentration of VA solution, the MS and Al samples are immersed in different plastic containers containing 400ml of seawater with pH value of 7.25 with no (0%) inhibitor added to it. A 5% (400ml) of the VA solution is poured into the measuring cylinder for each sample-Al and MS. The specimens are suspended by the strings and completely immersed in the different percentage test media. The same procedure is carried out for each of the different percentages (i.e. 10%, 15%, 20%, and 25%) and a total of 12 solutions are set up. The seawater used has 7.25 pH. At the end of every week (168 hours), the specimens are removed from the corrosive media. Observation and recording of appearance of the specimen, noting sites are done to analyze the effect of the VA solution on the AL and MS used for the STP. Values are obtained and graphs plotted on weight loss (WL) and corrosion rate (CR) versus the time. It is observed that the VA solution has different effect on the STP at different time and percentage of the VA solution introduced into the environment of the pipe. It was also observed that optimum inhibition of coupons is obtained between 15-25% of VA solution during the first four weeks of testing. At the fifth week, the inhibitor was gradually losing its effectiveness. This means that more inhibitor needs to be added at regular intervals in order to sustain the effectiveness of the inhibitor.