Electricity Generation Plants Research Articles

Corrosion investigation of electrodeposited cobalt-nickel-iron (CoNiFe) fasteners with the different deposition time

Abstract Corrosion has been acknowledged as one of the biggest opponents in applications and industries such as in motorized industries, oil and gas industries, manufacturing and chemical plants, electric power generation plants and concrete structuresUsing the electrodeposition process, Cobalt-Nickel-Iron (CoNiFe) nanocrystalline coatings were successfully synthesized onto mild steel fasteners (bolt and washer) with deposition times of 15, 30, and 45 minutes, respectively. The objective of this research is to study the corrosion behaviour of the CoNiFe coated onto the mild steel fasteners. The electrodeposition process was performed by controlling its operating parameters such as temperature, pH, current density, deposition time and electrolyte composition. The temperature used throughout the process was 50 °C in an acidic condition of pH 3. By varying the deposition times, the phase and crystallographic structure, surface morphology, grain size, microhardness, and surface roughness of the CoNiFe coatings were examined. Based on the FESEM micrographs, the grain sizes of the coatings were in the range of 85.34 nm to 95.01 nm. Dendrite and irregular shapes were observed for the microstructure of CoNiFe nanocoating. The CoNiFe nanocrystalline coating prepared with a deposition time of 45 minutes achieved the highest microhardness of 228 HVN. The surface roughness also increases with longer deposition time. It was found that by increasing the deposition time also enhanced the microhardness and magnetic properties of CoNiFe nanocoating. From the salt (fog) spray test, the longer deposition time used had the highest corrosion resistance. Thus, it can be concluded that the optimum deposition time of the electrodeposited CoNiFe coating on the mild steel fasteners was 45 minutes which produces optimum properties.

Flow characteristics and dispersion during the vertical anthropogenic venting of supercritical CO2 from an industrial scale pipeline

Pressurized pipelines represent the most reliable and cost effective way of transporting captured CO2 from fossil fuel-fired electricity generation plants for subsequent sequestration. Leakage of CO2 through a small puncture is the most common form pipeline failure during normal operation; such failures could lead to fracture. The study of pipeline depressurization and inventory dispersion behavior is of paramount importance for assessing the possibility of fracture propagation and the impact of CO2 pipeline releases on the surrounding environment. A large-scale fully instrumented pipeline (258 m long, 233mm i.d.) was constructed to study the pressure response, phase transition and dispersion of gaseous, dense and supercritical phase CO2 during vertical leakage through a 15 mm diameter orifice. The fluid pressures and temperatures in the pipeline were recorded to study the pressure response and phase transition inside the pipeline. Video cameras and CO2 concentration sensors were used to monitor the formation of the visible cloud and the gas concentration distribution in the far-field. There was a “two cold, intermediate hot” phenomenon during the vertical release in the dense and supercritical release due to the dry ice particle accumulation near the orifice. The intersection of the jet flow and settling CO2 mixture resulted in complex visible cloud forms in dense CO2 release.

Energy development in Vietnam's Mekong river delta: a 'green' or 'grey' outlook?

The Vietnamese Mekong river delta (MD) is recognised as the biggest agriculture and aquaculture region of Vietnam. The MD plays an important role in ensuring food security for the country. The MD also has many sensitive ecosystems reliant on the ecology of the Mekong river basin. However, during the last decade, many electricity generation plants, both renewable and non-renewable power projects, have been built and some will be built in the near future in the MD. These energy plants' construction and operation may prove to be a challenge to the national energy strategy. This paper is a monograph review of two sides of energy sector industrialisation in the MD with a focus on 'green' and 'grey' socio-economic development (as 'xanh' and 'xam' in Vietnamese respectively). 'Green' energy is understood as the electricity generated from inexhaustible sources and known as renewable energy. It emits fewer greenhouse gases and causes less harm to habitats in comparison to traditional fossil fuels and hydropower. 'Grey' energy is another word for non-renewable energy or polluting energy, which can have negative effects on human health, environment, and climate. This paper finds that the MD's energy development plans at present might not be as 'green' as expected, due to more 'grey' power plans in the planning pipeline. This paper also considers an outlook on energy prices and impacts on long-term sustainable development of the MD.

Integration of Process Modeling, Design, and Optimization with an Experimental Study of a Solar-Driven Humidification and Dehumidification Desalination System

Solar energy is becoming a promising source of heat and power for electrical generation and desalination plants. In this work, an integrated study of modeling, optimization, and experimental work is undertaken for a parabolic trough concentrator combined with a humidification and dehumidification desalination unit. The objective is to study the design performance and economic feasibility of a solar-driven desalination system. The design involves the circulation of a closed loop of synthetic blend motor oil in the concentrators and the desalination unit heat input section. The air circulation in the humidification and dehumidification unit operates in a closed loop, where the circulating water runs during the daytime and requires only makeup feed water to maintain the humidifier water level. Energy losses are reduced by minimizing the waste of treated streams. The process is environmentally friendly, since no significant chemical treatment is required. Design, construction, and operation are performed, and the system is analyzed at different circulating oil and air flow rates to obtain the optimum operating conditions. A case study in Saudi Arabia is carried out. The study reveals unit capability of producing 24.31 kg/day at a circulating air rate of 0.0631 kg/s and oil circulation rate of 0.0983 kg/s. The tradeoff between productivity, gain output ratio, and production cost revealed a unit cost of 12.54 US$/m3. The impact of the circulating water temperature has been tracked and shown to positively influence the process productivity. At a high productivity rate, the humidifier efficiency was found to be 69.1%, and the thermal efficiency was determined to be 82.94%. The efficiency of the parabolic trough collectors improved with the closed loop oil circulation, and the highest performance was achieved from noon until 14:00 p.m.

Optimization of Coke Oven Gas Desulfurization and Combined Cycle Power Plant Electricity Generation

Many steel refineries generate significant quantities of coke oven gas (COG), which is in some cases used only to generate low pressure steam and small amounts of electric power. In order to improve energy efficiency and reduce net greenhouse gas emissions, a combined cycle power plant (CCPP) where COG is used as fuel is proposed. However, desulfurization is necessary before the COG can be used as a fuel input for a CCPP. Using a local steel refinery as a case study, a proposed desulfurization process is designed to limit the H2S content in COG to less than 1 ppmv, and simulated using ProMax. In addition, the proposed CCPP plant is simulated in Aspen Plus and is optimized using GAMS to global optimality with net present value as the objective function. Furthermore, the carbon tax is considered in this study. The optimized CCPP plant was observed to generate more than twice the electrical efficiency when compared to the status quo for the existing steel refinery. Thus, by generating more electricity within...

Enhancement the Performance of Asphalt Pavement Using Fly Ash Wastes in Saudi Arabia

Saudi Arabia is the largest Arab country and is one of the most prolific producers of oil and energy consumption. The Kingdom uses heavy oil and diesel to generate electricity and desalinate seawater. This produces large amounts of ash, a toxic substance that is disposed of by landfill and may cause many environmental problems and contribute to pollution of groundwater, which is one of the most important sources of drinking water. This paper presents the possibility of using fly ash by-product waste from electric power generation plants to improve the properties of asphalt mixtures. This study investigates the use of two types of fly ash namely; class C and class F was used as a filler in two types of bitumen and asphalt material known as AC 40/50 and AC 60/70. The rheological performance of asphalt with different percentages of fly ash filler ranging from 0% to 10% with an increment of 2% was tested. The rheological properties of both asphalts modified using both types of ash were determined. The rutting factors of the modified asphalt with fly ash content were calculated using the rheological properties. The result indicates that rutting resistance of asphalt could be improved by both types of fly ash which can be lead to reduces the costs of repairing and rehabilitation of asphalt pavement and reduce environmental impacts of a significant amount of toxic waste fly ash. Class F fly ash shows higher rutting factor than class C. Also AC 60/70 asphalt possess higher rutting factor than AC 40/50 asphalt at both low and high temperature.

Robust block roots assignment in linear discrete-time sliding mode control for a class of multivariable system: gas turbine power plant application

This paper deals with the development of a new extended robust control algorithm based on the assignment of robust block roots to extended linear discrete-time sliding mode control; matrix fraction description (MFD) theory is used to improve the performance of the proposed control algorithm and make it more robust. To validate the proposed control algorithm, an application on a gas turbine system (GE MS5001P), which is used in electrical power generation plants, is presented in this paper. An autoregressive model with exogenous excitation is obtained for the studied system, based on the left MFD multivariable least-squares estimator, using real data obtained on-site in order to obtain a minimum-order model with optimum validation criteria. The main objective of the implementation of the proposed control algorithm within the presented application is to ensure stability in the dynamic behaviour of the gas turbine system. Furthermore, a comparison with some classical and modern controllers has been made to prove the effectiveness and robustness of the proposed control algorithm.

Exergy analysis and performance of a tug boat power generator using kerosene fuel blended with aspire methly ester

Diesel engine is most commonly seen in applications demanding a large power output, such as ships and electric generation plants. Exergy analysis has been used in the design technology such as simulation and performance assessment of various types of engines, for identifying parameters. In this case; the energy and exergy analyses of an eight-cylinder, four-stroke power generator using the kerosene fuels with blended 20/50 aspire methly ester (AME) have been performed. Energy and exergy rates for the engine were determined and then various performance parameters and energy and exergy efficiencies were calculated for each fuel operation and compared with each other. The results of tested biodiesel offer similar energetic performance as petroleum diesel fuel. Conservation of energy equation and the exergy balance for each test steps were determined using measured data. Finally, various energetic and exergetic performance parameters of the engine were evaluated and compared with each other. CO emissions were dropped when running on AME and its blends. The AME was found to have the highest exhaust temperature due to its oxygen content 11.2% higher than marine fuel. The maximum NOx emission was indicated 100% AME blend. However, the NOx emissions were higher, using marine blends.

Integrated Assessment of Palm Oil Mill Residues to Sustainable Electricity System (POMR-SES): A Case Study from Peninsular Malaysia

Generating electricity from biomass are undeniably gives huge advantages to the energy security, environmental protection and the social development. Nevertheless, it always been negatively claimed as not economically competitive as compared to the conventional electricity generation system using fossil fuel. Due to the unfair subsidies given to renewable energy based fuel and the maturity of conventional electricity generation system, the commercialization of this system is rather discouraging. The uniqueness of the chemical and physical properties of the biomass and the functionality of the system are fully depending on the availability of the biomass resources, the capital expenditure of the system is relatively expensive. To remain competitive, biomass based system must be developed in their most economical form. Therefore the justification of the economies of scale of such system is become essential. This study will provide a comprehensive review of process to select an appropriate size for electricity generation plant from palm oil mill (POM) residues through the combustion of an empty fruit bunch (EFB) and biogas from the anaerobic digestion of palm oil mill effluent (POME) in Peninsular Malaysia using a mathematical model and simulation using ASPEN Plus software package. The system operated at 4 MW capacity is expected to provide a return on investment (ROI) of 20% with a payback period of 6.5 years. It is notably agreed that the correct selection of generation plant size will have a significant impact on overall economic and environmental feasibility of the system.

Functionalizing bottom ash from biomass power plant for removing methylene blue from aqueous solution

In order to seek a possible path for utilization bottom ash, the solid waste from biomass incineration for power generation, its basic characteristics were investigated, and removing methylene blue (MB) from aqueous solution was attempted as well. Results indicated bottom ash dominantly contained Si and Ca-related minerals with >35 mineral elements, meanwhile, it was typically characterized by alkalinity (pH of 9.5) and low specific surface area (14.5m2/g). As the only bottom ash was employed for removing MB, removal efficiency was lower than 44%, however, it was greatly improved to 100% as hydrogen peroxide was supplemented (final concentration of 4.0%). Based on the elucidated mechanisms, Fenton-like reaction was triggered by bottom ash, which was dominantly responsible for removing MB, rather than the adsorption by bottom ash. Besides, increasing reaction temperature and duration dramatically promoted MB removal by bottom ash with the aid of hydrogen peroxide (HBA). A great promotion on MB removal from 92.3mg/g to 143.9mg/g was achieved as pH was adjusted from 2.0 to 5.0, indicating MB removal was pH-dependent. The maximum removal of 260.9mg/g was achieved by HBA at a relatively high initial MB concentration of 2000.0mg/L, suggesting a great potential in treating dye wastewater by functionalizing bottom ash with the aid of hydrogen peroxide. Moreover, the released heavy metals and derived by-products from MB removal were acceptable in consideration of their potential environmental risks. Thus, the current work offers a new path to valorize the solid waste in biomass electricity generation plant.

Performance based approach for electricity generation in smart grids

The Power Grid balance requires the organization of multiple supply plants to match the electricity demand of the users’, starting from the most accurate forecasts available and with the need of continuous adjustments based on the actual demand profile. The power dispatching is currently based on a day-ahead wholesale market, which fixes an hourly price based on the offers and bids of producers and buyers. In this paper an alternative approach is proposed, with the integration of performance indicators of the electricity generation plants. Optimization algorithms at the base of Smart Grids operation could support a multi-objective approach that overcomes a simple economic optimum. The aspects that have been considered are the renewable energy share, the primary energy consumption, the global emissions (i.e. CO2) and the local emissions (i.e. NOX, CO, PM, etc.). A precise calculation of these performance indicators is proposed for three real natural gas combined cycles, and the results are compared with the average data for the electricity produced in Italy and supplied to the Power Grid. The strong variability of those indicators highlights the importance of performing detailed analyses with up-to-date actual operation data, as the evolution towards sustainability targets in Smart Grids require an integrated approach.

Балансово-оптимізаційна модель взаємодії енергетики з паливними галузями ПЕК України з урахуванням європейських екологічних норм

The balance-optimization model of production type has been developed for simulation and forecasting of mutually coordinated operation of power sector and fuel industries within fuel and energy complex (FEC) of Ukraine. A distinctive feature of the model is the simultaneous consideration of fuel and power industries making it possible to assure energy security requirements by evaluating the dependable development levels of primary energy sources and producers of electricity and heat. Production of fuel resources, as well as their use by electric and thermal energy generation plants, is presented in the model within the framework of a single approach by L.V. Kantorovich’s production activity, providing optimal solution for mutually corresponding amounts of fuel and energy domestic production in the energy sector development and forecasting problems. The production activity, as a structural basis of the model of production type, was used to account environmental pollutants as additional products of electricity and heat production technologies for assessing the impact of European environmental legislation.

Malmquist productivity index for multi-output producers: An application to electricity generation plants

Different types of plants are used to generate electricity in the US: single-, multi-, and mixed-electricity plants. In this paper, we question the best type/design of plants for both renewable and non-renewable electricity. To do so, we suggest a new index that takes the form of a Malmquist productivity index. The specificity of our new index is that it offers the option to investigate the performances and the causes of the performance changes for each type of electricity separately; this is not possible when relying on more standard indexes. Moreover, our new index takes the links between the inputs and the outputs into account, and is nonparametric in nature. Using our index, we study the performances of more than 5000 plants for the period 2000–2012. Our findings reveal that single-electricity plants perform better for renewable electricity, while multi-electricity plants perform better for non-renewable electricity. This is coherent with the decreasing importance of multi-electricity plants in the US, and the increasing importance of single-electricity plants producing renewable electricity. Furthermore, our results do not suggest that combining renewable and non-renewable electricity generations within a plant improves the performance of the plants. Finally, we demonstrate that the reasons for the changes in performance are different for each type of electricity and plant.

Evaluation of Magnetostrictive Transducers for Guided Wave Monitoring of Pressurized Pipe at 200 °C

Many piping networks in processing plants, such as refineries, chemical plants, and electric power generation plants, are operated at elevated temperatures (≥250 °F or 121 °C). Failure of these insulated high temperature pipes can cause a major disruption of plant operation. In addition to inspection during the regular plant shutdowns, processing industries are looking for ways to inspect and monitor these pipelines on-line to ensure safe operation of the plants. Permanent monitoring of high temperature structures would require addressing the following technical problems: supporting the sensor functionality at high temperatures, ensuring the probe durability, and maintaining good coupling of the probe to the structure. In this work, a probe utilizing magnetostrictive transduction was tested on a mockup at 200 °C and produced a steady high amplitude signal over a period of 270 days. Probe performance parameters such as signal to noise ratio, data reproducibility, and sensitivity to anomalies are discussed.

Dynamic behavior of a high-temperature printed circuit heat exchanger: Numerical modeling and experimental investigation

Printed circuit heat exchanger (PCHE) is one of the leading intermediate heat exchanger (IHX) candidates for the Very High Temperature Reactors due to its capability for high-temperature and high-pressure applications. An IHX serves to isolate the reactor primary system from electricity generation and process heat application plants, and therefore must be robust to maintain the entire system integrity during normal and off-normal conditions. Understanding the PCHE dynamic behavior is of importance in the design of a PCHE-type IHX since the dynamics of the PCHE will influence accident progression in most accident scenarios. In addition, any transient in the power conversion unit or process heat plant will propagate back to the reactor primary system via the PCHE. In this study, the dynamic behavior of a zigzag-channel PCHE, subject to helium inlet temperature variations and helium mass flow rate step changes on both the hot and cold sides, was simulated and analyzed. Three sets of transient tests were experimentally conducted in a high-temperature helium test facility to examine the dynamic performance of the PCHE and to assess the PCHE dynamic model. Comparisons of the numerical results and experimental data indicate that the numerical solutions are sufficiently accurate and that the feasibility of the dynamic model developed for predicting the steady-state and transient performance of the PCHE is confirmed.

Fuel prices, restructuring, and natural gas plant operations

Switching from coal-fired to natural gas-fired generation and increasing the thermal efficiency (energy generated per unit of energy burned) of fossil fuel fired electricity generation plants have been identified as ways of achieving meaningful emission reductions. In this study, we examine the fuel-price responsiveness across gas plant technologies and across the market structures in which the plants operate. We find that there are significant differences in the generation and efficiency responses of gas plants to fuel prices across generation technologies and market structures. Specifically, our results indicate that, regardless of market structure, generation from natural gas combined cycle (NGCC) plants is responsive to both coal and gas prices, but that generation from simple cycle (NGSC) plants only respond to gas prices. On the other hand, with respect to efficiency, we generally find that only NGCC plants operating in deregulated regions show statistically significant efficiency improvements in response to coal price increases and that, generally, neither NGCC or NGSC plants, regardless of market structure, respond in any significant way to gas prices. Finally, using these parameter estimates, we calculate emissions savings from efficiency improvements and fuel-switching possibilities.

Assessment of Risk Management Concerning Environmental Pollution Resulting from Musayyib Electricity Generation Plant in Babylon Governorate

Assessment of Risk Management Concerning Environmental Pollution Resulting from Musayyib Electricity Generation Plant in Babylon Governorate

Utilization of eucalyptus for electricity production in Brazil via fast pyrolysis: A techno-economic analysis

Abstract A process model of a 2000 metric ton per day eucalyptus Tail Gas Reactive Pyrolysis (TGRP) and electricity generation plant was developed and simulated in Pro/II software for the purpose of evaluating its techno-economic viability in Brazil. Two scenarios were compared based on operational conditions in the country: a single biomass to bio-oil TGRP production facility and a distributed/satellite processing that consists of several small TGRP production facilities with aggregate capacity similar to the single one, both feeding into one centralized electricity generation plant. The selling price at the breakeven point of the electricity generated via TGRP was estimated to be US$0.34 and US$0.62 per kWh for the single and the distributed scenarios respectively, considering a 10-year payback period. The single capacity pyrolysis and electricity generation facility is found to have better economic benefits over the distributed plants of small sizes under the current conditions in Brazil. The results therefore indicate that pyrolysis of eucalyptus wood for electricity in a single facility cannot be competitive with the current electricity cost in Brazil (US$0.08–0.13/kWh) at present time. Considering auxiliary benefits such as climate change and carbon credits, plus the continuous increasing in the electricity market price in Brazil, both scenarios could be competitive in the future.

Technical Analysis of Collapse in Tunnel Excavation and Suggestion of Preventing Appropriate Applicable Methods (Case Study: Sardasht Dam Second Diversion Tunnel)

In order to either optimal use of water resource of KELAS river basin and electrical energy generation, Sardasht Dam and power plant are designed. Dam water diversion system includes two tunnels with inner diameter of 7 m. Several collapses have occurred in portal of second diversion tunnel (A2) which has created large cavity in tunnel crown. In order to prevent collapse, various ways such as steel sets installation and also grouting to increase strength of surrounded rock mass, are prescribed but none of technics could not to ban caving in. considering this fact that in order to continue tunnelling process, collapse zone should be passed, a solution or solutions must be suggested to overcome consecutive and dangerous collapses problem. In order to decrease tunnelling risks, in this research, using both experience and knowledge obtained from previous proposed executive solution to similar cases and technically analysis of occurred collapse in current diversion tunnel, it has been tried to suggest a new appropriate solution which defeat the problem. Finally, in order to stabilize of tunnel crown, as an effective and applicable solution, constructing retaining crown by means of rock bolts, was introduced.

Modifikasi Topologi Pengendali PID untuk Automatic Voltage Regulator Generator Sinkron

Automatic voltage regulator (AVR) is one of key elements in an excitation system which controls the synchronous generator terminal voltage in an electrical power generation plant. PID control algorithm in an AVR has been designed to obtain good response towards voltage reference without considering the effect of torque disturbance. This paper proposes a PID with modified topology for a digital AVR in order to regulate the generator terminal voltage in more speedy and more accurate, while maintaining robustness against torque disturbance. Performance of the digital AVR has been compared with conventional PID controller through experiments using a hardware in the loop (HIL) system. The experiment results show that the proposed PID with modified topology provides better performance than the conventional PID controller. Under torque disturbance, the proposed algorithm provides 83% smaller steady state error and 4.8 second shorter settling time compared to the conventional PID controller. When the reference voltage changes, compared to the conventional PID controller, the proposed algorithm provides 15% smaller steady state error, 79% smaller overshoot, and 0.2 second shorter settling time.