bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of New Instant Technology of Natural Gas Quality Determination
Authors: Koturbash Taras , Karpash Maksym , Darvai Iryna , Rybitskyi Ihor , Kutcherov Vladimir 
Published: February 2014

World experience shows that important factor in the calculations for natural gas consumption between suppliers and consumers is not only the volume of natural gas, but the quality indicators. With gas market liberalization, gas properties are expected to vary more frequently and strongly (composition, heating value etc.). Quality of natural gas is currently a topical issue, considering the steady increase of gas consumption in the world in recent decades. Existent chromatographs and calorimeters are very accurate in gas quality determination, but general expenditure and maintenance costs are still considerable. Market demands alternative lower cost methods of natural gas quality determination for transparent energy billing and technological process control.
Investigation results indicate that heating value (HV) is a nonlinear function of such parameters as sound velocity in gas, N2 and CO2 concentration. Those parameters show strong correlation with natural gas properties of interest (HV, density, Wobbe index), during analysis conducted on natural gas sample database. For solving nonlinear multivariable approximation task of HV determination, artificial neural networks were used. Proposed approach allowed excluding N2 concentration from input parameters with maintenance of sufficient accuracy of HV determination equal to 3.7% (with consideration of N2 concentration – 2.4%) on sample database. For validating of received results corresponding experimental investigation was conducted with reference analysis of physical and chemical parameters of natural gas samples by gas chromatography and followed superior HV calculation according to ISO 6976:1995. Developed experimental setup consist of measuring chamber with ultrasonic transducer, reflector, pressure, temperature and humidity sensors, ultrasonic inspection equipment for sound velocity measurements and CO2 concentration sensor with relevant instrument. The experimental setup allows measurement of sound velocity at 1MHz frequency and CO2 concentration in natural gas sample along with parameters control (temperature, humidity, pressure). The HV calculation algorithm was based on specially designed and trained artificial neural networks.
Experimental investigation of proposed approach was conducted on 40 real samples of locally distributed natural gas. Obtained results, in comparison to reference values, showed absolute error in Lower HV (net calorific value) determination equal 166 kJ/m3, while relative error was equal 4.66%. Developed technology allows construction of autonomous instrument for instant natural gas quality determination, which can be combined with volume meters in order to provide transparent energy flow measurement and billing for gas consumers. Additionally it can be used for gas sensitive technological process control.
Parallel Flow Boiler Designs to Minimise Erosion and Corrosion From Dust Loaded Flue Gases
Authors: Peterseim Juergen H. , Hellwig Udo , Endrullat Karin 
Published: February 2014

Improving power plant performance, availability and operational costs is crucial to remain competitive in today’s competitive energy market. The boiler is a key component to achieve these objectives, particularly so when using challenging fuels, such as municipal solid waste or exhaust gases with high dust contents.
This paper describes an innovative boiler design that has been used for the first time in an Energy from Waste plant in Bamberg, Germany. The new boiler design disregards the traditional heating surface arrangement and instead uses tube bundles arranged in parallel to the gas flow, which provides several advantages, such as reduced fouling. The paper describes the Bamberg project (boiler design and project highlights) and first operational results after 30,500h of operation.
Additionally, the paper investigates further options to reduce fouling through the use of dimpled tubes, especially the ip tube® technology. The technology is presented as well as first test results of such tubes in the Energy from Waste plant Rosenheim, Germany.
The paper concludes with further applications for the parallel flow boiler design, such as cement kilns, to outline future markets.
One Dimensional Model for Rotating Channels in the Turbine System: Part 2 — Formulation and Validation for Film Condensation
Authors: Krishnan R. Murali , Dweik Zain , Prabhudharwadkar Deoras 
Published: February 2014

This paper provides an extension of the previously described [1] formulation of a one-dimensional model for steady, compressible flow inside a channel, to the steam turbine application. The major challenge faced in the network simulation of the steam turbine secondary system is the prediction of the condensation that occurs during the engine start-up on the cold parts that are below the saturation temperature. Neglecting condensation effects may result in large errors in the engine temperatures since they are calculated based on the boundary conditions (heat transfer coefficient and bulk temperature) which depend on the solution of the network analysis.
This paper provides a detailed formulation of a one-dimensional model for steady, compressible flow inside a channel which is based on the solution of two equations for a coupled system of mass, momentum and energy equations with wall condensation. The model also accounts for channel area variation, inclination with respect to the engine axis, rotation, wall friction and external heating. The formulation was first validated against existing 1D correlation for an idealized case. The wall condensation is modeled using the best-suited film condensation models for pressure and heat transfer coefficient available in the literature and has been validated against the experimental data with satisfactory predictions.
Life Cycle Analysis of Linear Fresnel Solar Power Technology
Authors: Hang Yin , Balkoski Kevin , Meduri Phani 
Published: February 2014

Solar power generation technologies are categorized as Concentrated Solar Thermal Power (CSP) and PhotoVoltaic (PV). AREVA’s Compact Linear Fresnel Reflector (CLFR) system is a CSP power generation technology which compares favorably with other technologies in terms of its land efficiency and environmental impact. Analysis of the costs and benefits of solar technologies can inform their design and influence environmental and economic policies.
This paper reports a comprehensive “cradle to grave” life cycle analysis (LCA) of AREVA’s CLFR technology. A unique element of this study is the availability of comprehensive inventory data from AREVA’s Reliance project, a 125 MWe Solar CLFR power plant under construction in India. Using actual project data showed the energy payback time was about 8.2 months and the greenhouse gas intensity was about 31 g-CO2/kWhe. Sensitivity analysis identified that the environmental performance is most sensitive to the solar intensity represented by direct normal irradiance. This study also compares AREVA’s CLFR technology with other leading solar power generation technologies. AREVA’s CLFR has the similar energy payback time and greenhouse gas intensity as other CSP technologies, and it has lower environmental impact compared to flat-plate PV systems.
Multi-Objective Optimization of Runner Blades Using a Multi-Fidelity Algorithm
Authors: Bahrami Salman , Tribes Christophe , Devals Christophe , Vu Thi C. , Guibault François 
Published: February 2014

A robust multi-fidelity design optimization methodology has been developed to integrate advantages of high- and low-fidelity analyses and alleviate their weaknesses. The aim of this methodology is to reach more efficient turbine runners with respect to different constraints, in reasonable computational time and cost. In such a framework, an inexpensive low-fidelity (inviscid) solver handles most of the computational burden by providing data for the optimizer to evaluate objective functions and constraint values in the low-fidelity phase. An open-source derivative-free optimizer, NOMAD, explores the search space. Promising candidates are selected among all feasible solutions using a filtering process. The proposed filtering process accounts for Pareto optimal solutions and considers solutions which are different in the design variable space and are dominant in their local territories. A high-fidelity (viscous) solver is used outside the optimization loop to accurately evaluate filtered solutions. Accurate information achieved by high-fidelity analyses is also employed to recalibrate the low-fidelity optimization.
The developed methodology demonstrated its ability to redesign a Francis turbine blade for a given best efficiency operating condition. The original and optimized cases were evaluated and compared for a complete range of operating conditions by calculating the efficiency curves and losses of different components. The optimal blade has provided an efficient runner for the given operating conditions considering the design constraints.
Stator Winding Ground Protection Failures
Authors: Maughan Clyde V. 
Published: February 2014

The fundamental neutral over-voltage relay 59GN commonly used in generator protection does not respond to grounds in the bottom ∼5% of the stator winding. Recent experience with four such failures to large generators suggests that this lack of protection can be a disastrous deficiency. Each of the four failures discussed in this paper caused massive damage to the generator, and collectively had a total cost, including repair and loss of generation, close to $500,000,000.
This paper describes those four failures, and discusses newer ground relay systems that monitor and protect the entire stator winding for grounds. The objective of this paper is to encourage owner/operators to add one of the newer relay systems.
Improving the Rail Car Unloading of Solid Fuels
Authors: Dumbaugh George D. 
Published: February 2014

The fast unloading of solid fuels shipped in bottom dump Rail Cars can be challenging when finances are limited. This presentation will explain the achievement of fast Rail Car unloading at a relatively low cost. An upgraded design of a trackside Rail Car Discharger is now being appraised. This kind of unloader pneumatically extends a longitudinal member that engages and vibrates one side of the car. Previously, it was designed to vibrate and unload cars constructed of Steel.
When oil became more costly, the same standard car began to be made of Aluminum, which reduced its freight rate. That kind of car prompted the upgrade in the design of this type of Discharger. For example, all the stresses transferred to the car by the vibration had to be markedly reduced. The unloading of a 100 car Unitrain that had a 100 ton load in each car was wanted to be done in 4 hours. This equates to the unloading time of Rotary Car Dumpers.
The first redesigned Discharger has been in productive service for more than 1 year. To date, the longest Unitrain to be unloaded is 80 cars, which was easily emptied in 4 hours. While a Unitrain with 100 cars is still being awaited, this unit is heralded for its proven accomplishments. Namely, it can equal the performance of a Rotary Car Dumper at less than about a fourth of the cost.
To observe this fast unloading of Aluminum cars, the installation is located in southwest Ohio. A requested site visit could be arranged.
Burning Uncleaned Solid Fuels
Authors: Dumbaugh George D. 
Published: February 2014

The purpose of this presentation is to qualify a method of continuously and efficiently burning “dirty” solid fuels. Thus, the fuel cost is reduced and a significant savings is realized.
Looking back on the many years of burning coal, a Preparation Plant was always involved in its supply. The delivered price took into account the extra cost for cleaning the 2″ × 0 “steam coal”.
Following a request issued by the DOE in Illinois, Kinergy aligned with Riley Power in Massachusetts to develop an improved Vibrating Stoker Grate. Delivered in 2006, and “started up” in 2007, it has been in productive use for about 5 years.
One of the most significant gains was the successful, continuous burning of “Run of Mine” (ROM) Coal. If this so-called “dirty” coal can be burned, then most of the cleaning done by a “Prep Plant” can be set aside, which is said to lower the cost of the coal by at least 35%.
Further, other “dirty” solid fuels derived from waste, such as wood bark, shredded rubber tires, municipal solid waste (MSW and RDF) can also be burned. Usually the Power Plant is paid to accept these waste fuels.
The maintenance of this Vibrating Stoker Grate is minimal and its productive availability is about 95%. Thus, it deserves attention.
To observe the Vibrating Stoker Grate that successfully burns ROM Coal, it is located in the southern part of Illinois.
Evaluation of Ethanol as a Fuel for Gas Turbines
Authors: Carvajal-Mariscal Ignacio , Sanchez-Silva Florencio , Jaramillo-Martínez Rodrigo , Polupan Georgiy 
Published: February 2014

In this paper, the results of the evaluation of using ethanol in a GE 61B gas turbine are presented. For better understanding, combustion analysis for natural gas was performed as a comparison point, calculating fuel and air requirements at the entrance and exit of the combustion chamber, obtaining the principal emissions for both fuels at different temperatures and relationships air-fuel.
Using design data taken from the manufacturer website, the four main processes of a complete Joule-Brayton cycle were calculated. In that way, the results were used as a thermodynamic basis in this work. Focus on the combustion turbine, setting the temperature at the entrance of the combustion chamber and varying the temperature at turbine inlet. Afterward, using the temperatures resulted by the calculations, stoichiometric air-fuel ratio and mole fractions were found. Finally, varying air-fuel ratio at diverse mixtures, there were obtained the emissions for both fuels.
As results, there were obtained the fuel requirements for natural gas and ethanol, finding that for ethanol, due to its lower calorific value, the amount of fuel is higher in order to obtain the required temperature. In terms of emissions, there was no convincing evidence that ethanol represents a minor emission source than natural gas; therefore, it could be a good substitute of natural gas in those countries were ethanol is produced.
A Practical Guide for Recognizing Elastic Follow-Up in Existing Power Piping Systems and Minimizing its Effects
Authors: Kimball Lange 
Published: February 2014

High temperature, high pressure steam piping can fail for many reasons. This can include some combination of metallurgical, operational, fabrication, erection and design short comings. This has proven that high-energy piping systems are not maintenance free and have a finite service life.
From a safety and reliability point of view it is increasingly important to determine when this life is expended before failure occurs. This requires that conditions that can reduce life are recognized. Once recognized, it is equally important that these conditions be addressed in a manner that will help prevent personnel injury, forced outages and high repair costs.
The ASME B31.1 Code states that piping is “subjected to strain concentrations due to elastic follow-up of the stiffer or lower stressed portions.” However, the phenomena of “elastic follow-up” is often overlooked in the design of creep prone piping such as main steam and hot reheat. It is also difficult to identify in the field. This paper addresses a methodology to recognize elastic follow-up in existing piping systems, possible consequences and the means to minimize its effect.
Thermosyphon Cooler Hybrid System for Water Saving Power Plant Heat Rejection
Authors: Carter Thomas P. , Furlong James W. , Bushart Sean P. , Shi Jessica 
Published: February 2014

As noted in a Summer 2007 EPRI Journal article entitled Running Dry At The Power Plant, “Securing sufficient supplies of fresh water for societal, industrial, and agricultural uses while protecting the natural environment is becoming increasingly difficult in many parts of the United States. Climate variability and change may exacerbate the situation through hotter weather and disrupted precipitation patterns that promote regional drought.” Currently, in the United States, thermoelectric power production accounts for approximately 39% of freshwater withdrawals and 3% of overall fresh water consumption.
The Electric Power Research Institute, EPRI, as part of its Technology Innovation (TI) program, is collaborating with Johnson Controls to conduct a feasibility study comparing the performance of a water saving Thermosyphon Cooler Hybrid System (TCHS) with other heat rejection systems for power plant applications. The TCHS employs a sensible heat rejection device, a thermosyphon cooler (TSC) in conjunction with an evaporative heat rejection device, an open cooling tower, to satisfy the annual cooling requirements of a given power plant. By reducing the evaporative heat load, the TCHS can significantly reduce the annual water consumed for cooling while still maintaining peak power plant output on the hottest summer days.
Operational details of the Thermosyphon Cooler Hybrid System are presented. Additionally an overview of the cooling system simulation program, based on an 8,760 hourly analysis, used in the feasibility study is discussed. Results comparing the water use and additional fan power requirements between power plants employing a traditional all evaporative system and the TCHS are discussed for two different climatic locations. The concept of incorporating the cost of water, cost of power, the current plant operating conditions, and the current ambient dry bulb temperature into the TSC fan control strategy are also explored. The simulation program performance model is currently being validated with testing of a 1MW prototype TCHS at the Water Research Center near Cartersville, GA. Finally, a conceptual design for a power plant scale TCHS is presented.
Operation and Maintenance in Icelandic Geothermal Power Plants: Structure and Hierarchy
Authors: Atlason Reynir Smari , Unnthorsson Runar 
Published: February 2014

The Icelandic geothermal industry can be traced back to 1908 and has developed an extensive knowledge from that time. Currently, seven geothermal power plants are operating on the island. The plants are operated and maintained efficiently by relatively few engineers. The power plants generally prefer marine engineers who have worked as chief engineers on fishing vessels. Marine engineers are preferred in the Icelandic geothermal sector because of their education and mentality learned while working on the sea. Teamwork, resourcefulness, proactive thinking and the will to assist with jobs beyond job description are among the qualities believed to be required.
This study was carried out in cooperation with three power companies who own and operate all the geothermal power plants in Iceland. The purpose was to study the geothermal power plants and their environment in order to identify the key factors for the effective operation and maintenance with few engineers. The results include a summary and an analysis of the structure and hierarchy and an analysis of the business environment. Lastly, the results from a comparison of work behavior between employees at geothermal plants, fishing vessels and from other sectors are presented. Results were not as expected; employees at the geothermal plant were less considered to their peers, more outspoken and seem to show less civic virtue to their companies.
Feasibility and Applications of Supercritical Carbon Dioxide Brayton Cycles to Solar Thermal Power Generation
Authors: Schmitt J. , Willis R. , Frederick N. , Amos D. , Kapat J. 
Published: February 2014

This paper focuses on unconventional thermodynamic cycles and their applications in alternative energy. It looks into these promising advancements, beginning with the exploration of trends in cost, efficiency, and the adoption of various sources of power. By studying historical trends, conventional means of obtaining energy are seen to be currently increasing in efficiency in smaller and smaller increments.
The second part of our study is the application of alternative configurations of the Brayton cycle. In particular, this paper analyzes a closed-cycle turbine with supercritical carbon dioxide as the working fluid. Beginning with a simple cycle calculation, this study adapts the cycle and explores the benefit of recuperated and combined cycle systems. A parametric study was also created, comparing the efficiency versus the specific power of each cycle. Consideration of supercritical carbon dioxide as the working fluid in turbomachine cycles may demonstrate an economic advantage in the global market.
This paper provides a perspective on the feasibility of these developments for realistic applications in industry. Also important to feasibility, it assesses trends in the cost of power generated by each cycle and energy source. With this information, choices may be made on which cycle is more economically promising in today’s market. The results of this study provide a clear indication of relative efficiencies. These efficiencies, in turn, determines the optimal design direction for a particular supercritical carbon dioxide cycle. In addition, the results provide insight into the effect of this technology on the cost and efficiency of concentrated solar power production.
Effects of Cavitation Damage on the Hydraulic Characteristics of a Gate Valve
Authors: Trivedi Vatsal , Farah Amjad , Harvel Glenn 
Published: February 2014

This paper explores the effects of cavitation damage on the hydraulic performance of a gate valve. Cavitation is the phenomenon in which a fluid evaporates to form vapor bubbles which then subsequently implode. A Computational Fluid Dynamics (CFD) model of water flowing through a partially opened 1 inch (2.54 cm diameter) gate valve was developed using Unigraphics NX 7.5. NX 7.5 utilizes a k-ε turbulent flow 2-equation model. The low pressure and high velocity regions were identified in the CFD model to predict the location of the cavitation site in the valve. In order to simulate the effects of ageing due to cavitation, a gate valve was mechanically damaged in different stages. Damaged and undamaged valves were then inserted in a hydraulic test loop to observe the flow rate and pressure drop across the valves. The valves’ hydraulic loss coefficient was then calculated and compared. The cavitation index of the damaged and the undamaged gate valves was also calculated to predict the likelihood of cavitation.
The results show that the aged valve had lower loss coefficients at the corresponding opening positions compared to the ones for the non-aged valve. Also, it was observed that the aged gate valve had less likelihood of cavitation compared to the non-aged gate valve.