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Assessment of Site Parameters and Heat Recovery Characteristics on Combined Cycle Performance in an Equatorial Environment

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World Journal of Engineering and Technology 2016年第2期4卷 313-324页

作者： Sidum Adumene samson nitonye Department of Marine Engineering Rivers State University of Science and Technology Port Harcourt Nigeria

This paper investigates the effects of site based parameters such as ambient temperature, humidity, altitude and heat transfer characteristic of a dual pressure heat recovery system on the performance of the combined cycle power plant within an equatorial environment. The bulk heat utilization and configuration of a dual pressure heat recovery system are investigated. It is observed that the heat system configuration play a vital role in optimizing the combined cycle overall performance, which has proportionality relationship with the operating ambient temperature and relative humidity of the gas turbine. The investigation is carried out within the ambient temperature range of 24℃ to 35℃, relative humidity of 60% to 80%, and a high level steam pressure of 60 bar to 110 bar. The results show that at 24℃ ambient temperature, the heat recovery system has the highest duty of 239.4 MW, the optimum combined cycle power output of 205.52 MW, and overall efficiency of 47.46%. It further indicates that as the ambient temperature increases at an average exhaust gas temperature of 530℃ and mass flow of 470 kg/s, the combined cycle power output and efficiency decrease by 15.5% and 13.7% respectively under the various considerations. This results from a drop in the air and exhaust mass flow as the values of the site parameters increase. The overall results indicate that decreasing the ambient temperature at optimum exhaust gas flow and temperature increases the heat recovery system heat duty performance, the steam generation, overall combined cycle power output and efficiency, which satisfies the research objective.

关键词： Gas-Turbine Ambient Temperature Humidity Combined Cycle Efficiency Power Output HRSG

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Analysis of the Effectiveness and Efficiency of the VA Solution on Offshore Pipelines and Ship Materials

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Open Journal of Marine Science 2020年第1期10卷 16-31页

作者： samson nitonye Prince Ugboga Department of Marine Engineering Rivers State University Port Harcourt Nigeria

The analysis of the effectiveness and efficiency of Vernomia amydalina (VA) solution as an inhibitor on offshore pipeline and Ship materials (Steel) was carried out with the preparation of the specimen and the VA solution. The specimens were kept in a workable state and the VA Solution (inhibitor) prepared from 1200 g of bitter leaf was plucked, weighed and crushed separately. 600 cl of water was added to each of the crushed leaves. The mixture was put in a filter cloth and squeezed with hand to filter out the active concentration ingredients responsible for corrosion inhibition, which produced a 2 M concentration of VA extract solution. After the experiment was carried out the specimen was air-dried and weighed to determine the corrosion rate and weight loss. This was followed by the determination of the inhibitor efficiency at the different hours and at different percentage/concentration of the VA solution on the specimen. Results were obtained for different hours and at different percentage (0%, 5%, 10%, 15%, 20% and 25% inhibitor)/concentration of the VA solution and graphs plotted. It was observed that at the first week of exposure to corrosive medium there was a substantial reduction in weight of coupons but over the next three weeks there was a gradual decline in weight loss and the corrosion rate reduced evenly. It can be said that the percentage of inhibitor to corrosive medium is insufficient. From the graphs plotted, the inhibitor efficiency is considered high when the concentration of the VA solution is high, which implies a right percentage of inhibitor needs to be administered to obtain good efficiency of the solution. Hence as the weeks go by it was clear that the inhibitor was gradually losing its effectiveness. This means that inhibitors need to be added at regular intervals to sustain the effectiveness of the inhibitor. It is also of vital interest to apply the right concentration of inhibitor since CR increases at high concentrations and temperatu

关键词： Vernomia amydalina Inhibitors Efficiency Mild Steel Corrosion Environment

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Analysis of Marine Pollution of Ports and Jetties in Rivers State, Nigeria

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Open Journal of Marine Science 2018年第1期8卷 114-135页

作者： samson nitonye Ofanson Uyi Department of Marine Engineering Rivers State University Port Harcourt Nigeria

Ports and jetties complex operations come with various forms of pollutions. The analysis of marine pollution from ports becomes very necessary and complicated due to the various types of pollution, sources, effects and different characteristics. The sources of environmental pollution other than ships and from industrial activities in port and jetties were critically looked at and analyzed. A complete review of the environmental pollution in ports and the tools to assess and minimize such negative environmental impact are analyzed. The instrument of questionnaires was employed and distributed among two seaports and one jetty;Onne, Okrika and Port Harcourt to collect respondents’ opinions on effects, sources and causes of marine pollution. The chi-square test for independence was used with 180 respondents from Onne port, Port Harcourt port and Okrika jetty. Water sample was collected from Onne seaport and pollution contents such as total petroleum hydrocarbon (TPH), bio-chemical oxygen demand (BOD), turbidity, pH and salinity were tested in the laboratory. The result shows that Onne water had a salinity level of 20,790 (mg/l) which under the salinity range of water is considered saline, a turbidity level of 4.00 (NTU) which was considered average comparing with a 5.00 (NTU) bench mark, BOD5 level of 0.48 (mg/l) which was considered pristine because most pristine seawater will have BOD below 1 (mg/l), pH level of 7.77 which falls under the range of sea water being alkaline (7.2 - 8.4), TPH level of 2.98 (mg/l) since all conditions of sampling and sample preservations were observed and the value is less than the DPR limit (10 mg/l). It was concluded that the activities in Onne port are within the acceptable limits. It was also observed from the questionnaire that a larger population of respondents in Onne, Okrika and Port Harcourt ports where conscious of the sources and effects of environmental pollution from their respective ports.

关键词： Pollution Ports Ships Salinity Sea Water Onne Okrika Port Harcourt

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Numerical Analysis of the RAP Characteristics of a Catamaran Vessel for Niger Delta Pliability

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Journal of Power and Energy Engineering 2019年第10期7卷 1-20页

作者： Daniel Tamunodukobipi samson nitonye Department of Marine Engineering Rivers State University Nkpolu Port Harcourt Nigeria

A proper characterization of catamarans performance in relation to demi-hull separation ratio (Sc/L) is imperative for optimal design and applications. Resistance, propulsion and good sea-keeping characteristics for various demi-hull separation ratios at different operating conditions are prime considerations. This work evaluates the Resistance and Propulsion (RAP) characteristics of a 72 m long catamaran for various values of Sc/L (0.3, 0.4 and 0.5). Both physical models and numerical methods are implemented for the analysis. The analysis shows that the frictional resistance (RF) of catamaran is parabolic and slightly higher than those of monohulls. However, catamarans have superior sea-keeping performance. The RF of catamaran dominates the total resistance (RT) at low speeds;however, at high Froude number (Fn > 0.25), wave-making resistance (Rw) becomes dominant, especially during humps. Consequently, the RT-curve and the effective power PE-curve oscillate in rhythm with the Rw-curve as the velocity increases. Again, the effect of residuary resistance interference due to demi-hulls separation ratio is marginal, except during humps. Also, four speed-regimes are identified such as: 1) Low-speed (Fn st hump (0.23 nd hump, high-speed (Fn > 0.60). The catamaran PE for Fn > 0.6 is very high and uneconomical. Therefore, for optimal performance, catamarans should have service speed limits not exceeding Fn = 0.6.

关键词： Resistance Propulsion Catamarans Mono-Hull High-Speed Craft

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Design Analysis of a Lightweight Solar Powered System for Recreational Marine Craft

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World Journal of Engineering and Technology 2018年第2期6卷 441-456页

作者： Daniel Tamunodukobipi nitonye samson Adumene Sidum Department of Marine Engineering Rivers State University Port Harcourt Nigeria

The design of a lightweight solar powered marine craft is considered in this report. Various design concepts were considered with respect to the hull type, resistance, aesthetics and the operating environment of the vessel. The planning hull-form catamaran was considered for the boat design. The resistance and other hydrodynamic characterization of boat were analyzed using the CAHI and Savitsky method. Detailed algorithm is developed for the sizing of the various components of the solar PV system for the boat. The hull resistance was found to be 740 N corresponding to the boat speed of 5?knot using the above stated methods. The motor power was obtained to be 2.239?kW (3 HP). Torqeedo outboard electric motor of 3?HP was selected for the boat propulsion. The battery bank was seized accordingly and four batteries of 235 AH and 12 V were selected for the storage of electric power for the boat propulsion. Hence, the solar PV module was sized. It was concluded that, due to the limited space for the installation of the PV module, additional source of power (land base) should be made available to completely charge the battery.

关键词： Solar Powered Marine Craft Vessel Propulsion Savitsky CAHI and Energy

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Numerical Design and Performance Analysis of a Tug Boat Propulsion System

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Journal of Power and Energy Engineering 2017年第11期5卷 80-98页

作者： samson nitonye Sidum Adumene Ukpokpo Umorami Howells Department of Marine Engineering Rivers State University Port Harcourt Nigeria

The aim of this project is to design and analyze the propulsion system for a tugboat for optimum performance. In so doing, certain approved procedures were followed;these procedures included getting the desired tugboat dimension, using ITTC methods, Gertlers charts, Bp charts etc. to estimate the bare hull resistance of the tugboat, estimating the effective power that must be employed to overcome this tug resistance. Numerical software code was developed to determine the various performance indicators of the propulsion system. The effective power was used as a basis for selecting the main engine and designing of a suitable propeller capable of propelling the tugboat for the various sea state were evaluated. Propeller cavitation was also put into consideration during this design. Hence in matching the engine to the propeller a series of calculations were done across a speed range of 300 - 500 rpm in other to effectively ascertain the engine-propeller matching point. The result shows that the point of engine-propeller matching is at 335 rpm and 2550 KW respectively. This provides a guide for the selection of a main engine with an acceptable sea service margins. All designs were done in accordance to classification organization and regulations.

关键词： Tugboat Propulsion System Engines Resistance Effective Power Speed

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Design Analysis and Optimal Matching of a Controllable Pitch Propeller to the Hull and Diesel Engine of a CODOG System

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Journal of Power and Energy Engineering 2018年第3期6卷 53-74页

作者： Okim Bartholomew Ogar samson nitonye Ikue John-Hope Department of Marine Engineering Rivers State University Port Harcourt Nigeria

The optimal matching of a propeller to the hull and the diesel engine of the combine diesel or gas (CODOG) system is a critical design analysis in ship building. In this research work, a controllable Pitch Propeller (CPP) was considered whereby the pitch was varied, but only the extreme pitch set the limit of operation and matching was done with the extreme pitch condition. It considers the performance analysis of the propeller, the hull and the engine both in design and off design conditions. Without propulsion a vessel built cannot move and so choosing the right propeller to match the hull and engine is very vital. The various processes involved in the matching of the propeller to the diesel engine and hull of the vessel are considered, in order to achieve optimal performance of the vessel. A Java program (prop-matching) was developed to facilitate the matching process. The graphs obtained are used to determine the matching point at corresponding speed and power. The thrust and torque developed under different conditions as well as their significance, considering the fact that the propeller is a CPP. The engine response in transient conditions in reaction to the turbo charger was considered, the matching graph of the turbo charger compressor was discussed, and the calculated mass flow rate with various engine speeds and boost pressure were also discussed. This program was further used in matching the propeller to the hull and diesel or gas engines of a F90 frigate. The corresponding propeller rpm and engine power with pitch ratios from the program were similar to those from the design of the frigates. The various thrust and torque coefficients and open water efficiency all correspond to the simulated results of those of the naval frigate.

关键词： CPP CODOG Propeller Matching Resistance Effective Power Speed

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Combating Corrosion in Transmission Pipelines in Marine Environment Using Vernomia Amydalina as Inhibitor

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Open Journal of Marine Science 2018年第4期8卷 450-472页

作者： samson nitonye Umoh Ofonime Emmanuel A. Ogbonnaya Ezenwa Department of Marine Engineering Rivers State University Port Harcourt Rivers State Nigeria Department of Mechanical/Marine Engineering Niger Delta University Amassoma Bayelsa State Nigeria

Pipelines are system of pipes designed to transport liquids, gases or solid/ liquid mixtures over long distances. Some are used for domestic, household and sewage purposes. Others are buried underground or submerged in water for transportation of natural oil and gas (O & G) products. In this work, the specimens had to be kept in a workable state and steps were 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 were done. Then degreasing of specimen in acetone and air-dried were carried out. Upon drying, the specimens were immediately weighed to obtain their initial weights. Twelve specimens were used for the test as follows: 6 Aluminum (Al);and 6 mild steel (MS) samples. With a 2 M concentration of Vernomia Amydalina (VA) extract solution, the MS and Al samples were immersed in different plastic containers containing 400 ml of seawater with pH value of 7.25 with no (0%) inhibitor added to it. A 5% (400 ml) of the VA solution was poured into the measuring cylinder for each sample-Al and MS. The specimens were suspended by the strings and completely immersed in the different percentage test media. The same procedure was carried out for each of the different percentages, 10%, 15%, 20%, and 25% and a total of 12 solutions were set up. The experimental procedure used was that seawater of 7.25 pH was obtained from Abonnema water front of Rivers State. At the end of every week (168 hours), the specimens were removed from the corrosive media. Observation and recording of appearance of the specimen noting sites were done. Cleanings of specimen with white handkerchief or tissue paper were carried out and washing of specimen with distilled water, scrubbing of specimen with a soft brush and dipping the specimen into acetone after washing, it was removed to air-dry and weig

关键词： Pipelines Corrosion Environment Sea Water Inhibitors Specimen VA Solution Corrosion Rate (CR) Weight Loss (WL)

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