bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved Alternatives for Monitoring Flow Accelerated Corrosion in the Steam Cycle
Authors: Kuruc Ken , Slovacek Denton , Sadar Michael J. , Johnson Luke
Published: February 2014

To date, a particle counter or monitor has traditionally been used to detect the transfer of corrosion products in a power generation steam cycle. While this method has been generally well accepted and documented, particle counters do not have a standardized method of calibration and usually need to be calibrated at each facility. Where multiple measurement points are desired, it can also become rather costly. The technology is also limited to detecting particles with a size of 2 microns or greater.

Quantifying the amount of iron in the water on site has also been challenging in the ultra low range. Colorimetric methods that could be readily used at the plant were limited to 9 μg/L or greater. This has furthered added to the challenge of ascertaining whether significant corrosion product transfer was occurring at a particular point in the process.

Data has recently been gathered to determine whether corrosion product transfer in the steam cycle could be detected using a laser nephelometer. The added benefit of this methodology is the ability to detect particles in the sub-micron size range. Preliminary results have been very encouraging.

To further support these results, a modified trace level iron test has been documented using colorimetric methods and a lab spectrophotometer. Finally, a correlation has been made between these two methods, offering the opportunity of using a continuous measurement to determine iron concentrations to 1 μg/L or lower. The data can be further related to plant load and cycle pH in order to shed further light on how these parameters influence flow accelerated corrosion.
Assessment of Life of Pressure Vessels and Pipes in Crude Oil and Gas Industries
Authors: Khalil M. Shahid , Akbar Sajjad
Published: February 2014

Fitness-for-service (FFS) assessments are quantitative engineering evaluations which are required to be preformed periodically in accordance with the published codes and standards to demonstrate the structural integrity of in-service components. This report summarizes the results of nondestructive in-service-inspection (ISI) of pressurized components conducted for condition assessment of the Dakhani Gas Processing Plant of Oil and Gas Development Corporation Ltd. (OGDCL) for the first time since its commissioning in December,1989. The non-destructive evaluation of the plant was required because of concerns for occurrence of sulphide-stress-cracking. Hydrogen embrittlement, hydrogen-including-cracking, weight-loss-corrosion, sulphur-stress-corrosion due to determental service conditions at Dakhani having low PH, High H2S, high chlorides and pressure of CO2.

The results have shown that microstructural changes associated with first and second stage of hydrogen attack have occurred in almost all of the pipe joints and pressure vessels. Hardness of some vessels has even exceeded the NACE limit of 220 HB. Effect of second stage of hydrogen attack are dominant in pipe joints, resulting in loss of hardness and strength because of decarburization. The results based on ultrasonic attenuation monitoring also indicate degradation of components. Random rounded indications have also been observed in some pipe joints during X-Ray radiographic testing that could serve as sites for failure initiation. The corrosion-under-insulation is observed for joints of piping spreading over a significant length. Localized corrosion and pitting is also observed in some locations of pressure vessels and piping. Ultrasonic thickness gauging has shown a significant variation in thickness for dish end and shell of some pressure vessels as well as for various joints of piping. In absence of periodic ISI data for the plant and keeping in view the results of non-destructive evaluation summarized above, the end-of-life (EOL) assessment of pressure vessels and piping is not possible and operation of the plant should be continued with a degree of caution. Any estimate of safe life assessment of the plant made at this stage would require revision on the basis of observed level of degradation through essential periodic in-service monitoring. In order to cope with the situation, it is recommended that monitoring of further degradation of microstructure and hardness along with flaw growth should be carried out after a period of 8x103 hours. Necessary remedial measures for rectification of flaws are requested. Non-destructive strain gauging is recommended to estimate data for safe life assessment of pressure vessels. Thermographic scanning of on-line in-service insulated pipelines is proposed for monitoring corrosion-under-insulation during plant operation.
Corrosion-Fatigue Prediction Methodology for 12% Cr Steam Turbine Blades
Authors: Salzman Ronald , Gandy David , Rieger Neville , Schönbauer Bernd , Tschegg Stefanie , Zhou Shengqi , Turnbull Alan
Published: February 2014

The useful life of a steam turbine and the establishment of turbine outage schedules are often determined by corrosion fatigue to the low pressure (LP) blades in the phase transition zone (PTZ). Developing an effective corrosion damage prediction methodology is an important step to successfully reduce the number of unscheduled steam turbine outages.

Tests with dual certified 403/410 12% Cr martensitic steel were performed to quantify the influence of corrosion pits on the fatigue life during testing in environments that are comparable to operational conditions. Threshold stress intensity factors ΔKth and fatigue limits Δσ0 were determined in air and two aqueous solutions. Additionally, stress-life tests were performed with pre-pitted specimens in air and aqueous solutions.

The data for transition from a pit-to-a-crack have been correlated using the Kitagawa Diagram. This presentation of the data relates the steady stress, cyclic stress and pit width to the prediction of fatigue failure. Ultrasonic fatigue testing was an essential aspect of this program. This testing technique makes it possible to accumulate cycles at a rate of approximately 20 kHz. At this rate one billion (109) cycles are accumulated in less than 14 hours. One billion cycles has been used as the definition for non-progressive crack or specimen run-out life. All of the data for the survival and failure stress intensity factor was well represented by the El Haddad refinement to the Kitagawa Diagram.

Based on these test results a comprehensive methodology has been developed to quantify the risk of corrosion-fatigue failure at a pit.
Effects of Hydrogen Enrichment on the Reattachment and Hysteresis of Lifted Methane Flames
Authors: Kribs James D. , Hutchins Andrew R. , Reach William A. , Hasan Tamir S. , Lyons Kevin M.
Published: February 2014

The purpose of this study is to observe the effects of hydrogen enrichment on the stability of lifted, partially premixed, methane flames. Due to the relatively large burning velocity of hydrogen-air flames when compared to that of typical hydrocarbon-air flames, hydrogen enriched hydrocarbon flames are able to create stable lifted flames at higher velocities. In order to assess the impact of hydrogen enrichment, a selection of studies in lifted and attached flames were initiated. Experiments were performed that focused on the amount of hydrogen needed to reattach a stable, lifted methane jet flame above the nozzle. Although high fuel velocities strain the flame and cause it to stabilize away from the nozzle, the high burning velocity of hydrogen is clearly a dominant factor, where as the lifted position of the flame increased, the amount of hydrogen needed to reattach the flame increased at the same rate. In addition, it was observed that as the amount of hydrogen in the central jet increased, the change in flame liftoff height increased and hysteresis became more pronounced. It was found that the hysteresis regime, where the flame could either be stabilized at the nozzle or in air, shifted considerably due to the presence of a small amount of hydrogen in the fuel stream. The effects of the hydrogen enrichment, however small the amount of hydrogen compared to the overall jet velocity, was the major factor in the flame stabilization, even showing discernible effects on the flame structure.
Prediction of Fouling and Slagging in Pulverized-Coal Fired Furnaces
Authors: Bar-Ziv Ezra , Korytnyi Efim , Perelman Miron , Saveliev Roman , Chudnovsky Boris
Published: February 2014

The objective of this paper is to develop a method for predicting the fouling dynamics and thermal resistance of a certain coal and its fly ash in a coal-fired utility boiler as well as determine the emissivity of the fly ash in order to optimize soomblowing procedures for fouling clean-up. The methodology comprises combustion experiment in a 50kW test facility, characterization of the coal and its mineral matter and the consequent fly ash as well a series of computational fluid dynamic simulations. Ash deposition from Cerrejon D Colombian and Billiton-Prime South African coals were studied and their behavior predicted in 575MW tangentially-fired and 550MW opposite-wall boilers. Good comparison was obtained between predicted results and actual data from the boilers.
Environmentally-Benign Conversion of Biomass Residues to Electricity
Authors: Davies Andrew , Soheilian Rasam , Zhuo Chuanwei , Levendis Yiannis
Published: February 2014

As petroleum resources are finite, it is imperative to use them wisely in energy conversion applications and look for alternative options as an energy source. Biomass is one of the renewable energy sources that can be used to partially replace fossil fuels. Biomass-based fuels can be produced domestically and may thus reduce dependency on fuel imports. Due to their abundant supply, and given that to an appreciable extent they are considered to be carbon-neutral, their use for power generation is of technological interest. However, whereas biomasses can be directly burned in furnaces, such a conventional direct combustion technique is ill-controlled and typically produces considerable amounts of health-hazardous airborne compounds [1,2]. Thus, an alternative technology is described herein to further address our increasing energy needs and, at the same time, utilize our biomass streams in an environmentally-benign manner. More specifically, a multi-step process/device is outlined to accept biomass, of various types and shapes, and generate an easily-identifiable form of energy as a final product. To achieve low emissions of products of incomplete combustion, the biomass is gasified pyrolyticaly, mixed with air, ignited and, finally, burned in nominally premixed low-emission flames. Combustion is thus indirect, since the biomass is not directly burned, instead its gaseous pyrolyzates are burned upon mixing with air. Thereby, combustion is well-controlled and can be complete. A demonstration device has been constructed to convert the internal energy of plastics into clean thermal energy and, eventually to electricity.
Considerations in Converting a Dual Shell or a Dual Pressure Coal Fired Plant Condenser Into a Combined Cycle Plant Condenser
Authors: Nadig Ranga
Published: February 2014

The design of a dual shell or a dual pressure condenser employed in a coal fired plant is different from that in a combined cycle plant. The coal fired plant dual pressure condenser is equipped with feedwater heaters in the condenser neck, extraction piping, an external flash tank and a large number of vents and drains. Dual shell or dual pressure condenser in a combined cycle plant does not include feedwater heaters in the condenser neck and the related extraction piping. There is no external flash tank and the number of vents and drains are minimal. Combined cycle plants have a higher steam flowrate, are required to operate in bypass mode and in certain instances have high make up water flowrate. Apart from the above major differences there are a number of minor differences that must be accounted and addressed when converting a coal fired plant dual shell or dual pressure condenser into a combined cycle plant condenser.

This paper highlights the major and minor differences in the design, construction and operation of dual shell or dual pressure condenser operating in a coal fired plants and combined cycle plant. The modifications required to convert the condenser from coal fired application to combined cycle application are discussed. Precautions to be followed in operating the condenser in the new role are addressed.
Analysis and Modification of the Design of Fluid Power Control System for the Improvement of Product Quality
Authors: Sadak Tahany W. , Mkawee Taha E.
Published: February 2014

This research investigation is focused on providing system performance under different operating conditions, with special focus on variations in the supply pressure. The investigations have been carried out for different system designs. The analysis of the results introduces the effect of system designs on its static and dynamic performance. Also, the investigations provide the effect of variations of system operating conditions and load value. A hydraulic system has been designed with variable velocity, pressure and load. The detailed examination has been carried out on a system that consists of a hydraulic power supply unit, control valves (pressure control valve, flow control valve, throttle valve and directional control valve). We have investigated the effect of adding a flow control valve (FCV) in the chosen circuit and also replacing the FCV with a proportional flow control valve (PFCV). In order to study the effect of this valve on system performance we examine the role of change of operating conditions and loading values on the system performance. Thus the displacement and speed of the piston of the hydraulic cylinder has been experimented under different values of supply pressure, flow rate, and load. We make this investigation to develop the performance evaluation by replacing the (FCV) by proportional flow control valve (PFCV) via position control so that one can achieve the static and dynamic performance of the system more accurate. Apparent improvement in flow rate ranges from 8% to 29.5% and dynamic response from 30 to 64%. The results reveal that this methodology allows one to achieve high quality of the product.
Torrefaction for Fuel Switching From Coal to Pure Biomass in Power Plants
Authors: Li Jun , Yang Weihong , Blasiak Wlodzimierz
Published: February 2014

Torrefaction changes the elementary composition of biomass and moves it towards to coal, and accordingly, torrefaction based co-firing system in a pulverized coal boiler have been proved as a promising option for direct co-firing with a large percentage of biomass. This work examined and assessed various torrefaction degrees influencing on emissions reductions and system performances in a 200MWe power plant. The raw PKS was torrefied at four different torrefaction temperatures, namely, 200°C, 250°C, 270°C, and 300°C, respectively. A series of analyses were performed to understand the impacts of torrefaction temperatures on mill power requirements, pollutions emissions, and boiler efficiency. According to the results, an enhanced torrefaction caused more energy consumption on biomass pretreatment process but less energy consumption on biomass grinding. When considering the boiler efficiency and emissions in together, torrefaction temperature of 275 °C is property option both for high boiler efficiency of 95% and a lower NOx emission of 100 mg/Nm3. A high torrefaction temperate is required when expecting an even lower NOx emission, but the boiler efficiency would be reduced at the same time. Therefore, a balance consideration of combustion efficiency and emission should be made for torrefaction based biomass-fired boiler.
A New Paradigm: Cycling Operations at Nuclear Power Plants in the United States
Authors: Lefton Steven , Kumar Nikhil , Hilleman Douglas , Agan Dwight
Published: February 2014

Nuclear power plants are no longer immune to cycling operation. While certain nuclear power plants in Europe have been performing load following operation, this type of operation has largely been avoided in the United States. Due to increasing contribution of nuclear generation in the mix, European operators were forced to make modifications to increase the maneuverability of their nuclear generation assets. However, in the United States, nuclear generation is still a relatively smaller contributor (19%), but with rapid increase in renewable generation, some nuclear plans are being asked to operate at reduced power and cycle to lower power levels. These shutdowns are typically of a short-term duration on a weekend or in periods of high renewable megawatt generation. With most future renewable integration studies advocating for increased flexibility on the grid, nuclear generation maneuverability will allow system operators with another resource to mitigate and reduce system costs.

This paper presents the results of a detailed study of a 1,150 MW boiling water reactor (BWR) nuclear plant when cycled to low loads. The authors present the relative damage of cycling to various reduced power levels 80% to 15% power levels compared to a cold startup and shutdown of a nuclear plant. An assessment was made of the systems that had fatigue damage and costs. We also discuss some of the limitations of cycling that a nuclear plant has and present and discuss recommendations to reduce damage and costs.
Dual Injection Distributed Combustion for Gas Turbine Application
Authors: Khalil Ahmed E. E. , Gupta Ashwani K.
Published: February 2014

Distributed Combustion has been shown to provide significantly improved performance with near zero emissions for stationary gas turbine applications. Characteristics of distributed combustion include uniform thermal field in the entire combustion chamber (improved pattern factor), ultra low emissions of NOx and CO, low noise, enhanced stability and higher efficiency. Distributed combustion with swirl have been investigated to determine the beneficial aspects of such flows on clean and efficient combustion under simulated gas turbine combustion conditions with ultra-low NOx emissions. Results are presented here on the impact of employing dual injection of air and fuel in contrast to single injection. Dual and multi injection is of great importance for combustor design scale up as to maintain flow similarities. Results showed that careful implementation of dual injection can result in emissions as low as single air/fuel injection method. With adequate fuel injection strategy, further reduction in emissions has been demonstrated. Results obtained on pollutants emission with dual injection and different fuel injection strategies at various equivalence ratios showed ultra-low emission (<5PPM NO and <15PPM CO) and high performance. OH* chemiluminescence revealed relative position of the flame within the combustor under various conditions for further improvements in distributed combustion conditions and to further reduce NOx emission.
Thermal Analysis of Nuclear Concrete Containment in Transition Zones Between Regions With Different Reinforcement
Authors: Wang Shen , Munshi Javeed A.
Published: February 2014

Primary and secondary nuclear containments serve the critical function of providing an external protection and a leak proof boundary for containing radiation in nuclear power plants. Reinforced concrete containment in a nuclear power plant typically has a cylindrical wall and a spherical dome. Within the cylindrical shell, it is common to use different hoop reinforcing ratios at different elevations, in order to optimize the design. Reinforced concrete containments are designed for thermal effects, generally following methods provided in the committee reports of ACI 307 for chimneys or ACI 349 commentary for nuclear concrete structures. The behavior of concrete structures under thermal effects has been studied for decades. It is well know that stresses resulting from thermal effects are self-relieving and that magnitudes of thermal forces and moments are directly related to the reinforcement within the concrete member. In particular, for a given thermal and mechanical load combination, more reinforcing steel the concrete section contains, larger thermal forces/moments will be observed with correspondingly less deformations. The conventional approach provided in aforementioned building codes is to solve the equilibrium of a given reinforced concrete section with a predetermined reinforcement configuration. However, no research has been conducted to study thermal forces and moments in transition zones interfacing two regions with different reinforcement configurations. The compatibility at the interface between two regions with different reinforcement introduces further redistribution of thermal forces and moments within the transition zone, which should be considered in the design.

In this paper, a comprehensive study has been carried out using the closed form mechanical solution, in order to evaluate the redistribution of thermal forces and moments at a conceptual interface within a reinforced concrete cylindrical containment, between two regions with different reinforcement configurations. Based on this, consideration for thermal design at such an interface is provided. A practical example is presented at the end of the paper to illustrate the use of the proposed design method, followed by the conclusion.
Energy Storage System Survey and Battery Case Testing
Authors: Duggal Inderjeet , Venkatesh Bala
Published: February 2014

Energy storage and renewables are important parts of smart grid systems of the future. This paper surveys applications of energy storage systems. It reviews various types of battery systems, flywheels, compressed air energy storage systems and thermal energy storage systems. Then the paper surveys all possible uses of energy storage systems such as volt-var control, frequency regulation, energy arbitrage, etc. Thereafter, the paper presents a proposed testing of large scale battery system at Ryerson University using a 1.2 MWh of battery storage system with a 370 kW converter system connecting a 13.8 kV substation. Detailed system architecture is presented that includes details of the battery system, power electronics, etc. The proposed tests to be completed are outlined explaining potential outcomes in those tests.
Impulse Response Technique: A Valuable Non-Destructive Method to Detect Flaws
Authors: Limaye Hemant S.
Published: February 2014

Impulse Response (IR) is a nondestructive testing technique in which “mobility” of the structural member under investigation is determined. Mobility is a complex ratio of particle velocity and the applied force. The test involves striking the surface of the structure with an instrumented hammer and measuring vibration response of the member. The time-domain data of the instrumented hammer (applied force) and the vibration sensor are collected and transformed into the frequency domain by the signal analyzer. The mobility of the member is obtained by calculating the transfer function of particle velocity and the applied force. The value of the mobility can be used to assess the condition of the member on a comparative basis. Tests can be performed on a variety of construction materials such as concrete, masonry, ceramic, thin steel or aluminum plates. The method has been successfully used to determine slab-on-grade support conditions, delaminations, voids, existence of grout under the machinery base plates or in concrete blocks or clay bricks. This paper presents a description and the equipment used in the method. In addition, case studies will be presented to show how the method was applied to document the internal conditions.
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.
Effect of Toluene Addition on Hydrogen Sulfide Combustion Under Claus Condition
Authors: Ibrahim Salisu , AlShoaibi Ahmed S. , Gupta Ashwani K.
Published: February 2014

Experimental results on the effect of different amounts of toluene addition to H2S gas stream are presented. Three toluene concentrations of 0.5%, 1% and 5% in H2S are presented and compared with the baseline case of 100% H2S/air combustion. Temperature data showed that addition of toluene to H2S gas stream increases the flame temperature because of large heating value associated with toluene. Addition of toluene resulted in the production of H2, which increased with increase in the amounts of toluene addition. Furthermore, increased addition of toluene concentration increased the asymptotic value of hydrogen sulfide due to oxidation competition between the formed H2 and H2S. The results also showed that the presence of CO triggers the formation of COS with toluene addition due to reaction of CO with SO2. The results revealed that SO2 mole fraction increased to a maximum value then decayed with distance along the reactor. Addition of toluene increased the rate of SO2 decay. These results have direct impact on sulfur capture in Claus reactor performance for sulfur capture.
PDF Calculation of Emission NO in Turbulent Diffusion Flame With Gas and Soot Radiation Thermal Effect
Authors: Liu Xiao , Zheng Hongtao , Li Yajun , He Hongbin
Published: February 2014

A turbulent pilot flame is numerically simulated considering thermal effect of non-gray gas and soot particles. with CFD code Fluent in this paper. A 41-steps skeletal with extended NO mechanism (SKEL) is used and different combustion models have been adopted to simulate the combustion in turbulence flame. The DO method is employed to solve the radioactive transfer equation. The WSGG model and the Moss-Brookes model are imposed to consider the radiation effect of non-gray gases and soot. The results compared with experimental data of the “Sandia Flame D” published by the international TNF workshops on turbulent flames shows that the C-PDF model with detailed mechanism is able to accurately predict combustion species and even minor mass fraction of OH; the gaseous radiation has a significant effect on temperature and emission (NO). In addition, although soot radiation represents a relatively small portion of the total radiation heat transfer in pilot diffusion flame, it can lead to a drop of peak temperature up to 8K according to simulation. It is suggested that in simulation where soot is prone to produce, soot radiation thermal effect should be taken into account to capture more accurate prediction of NO.
Evaluation of Irradiation Effects on Concrete Structure: Background and Preparation of Neutron Irradiation Test
Authors: Maruyama Ippei , Kontani Osamu , Sawada Shohei , Sato Osamu , Igarashi Go , Takizawa Masayuki
Published: February 2014

Methods for assessing the soundness of concrete exposed to irradiation are being developed within the framework of a project of the Nuclear Regulation Authority (NRA) “Japan Ageing Management Program for System Safety”. This paper presents the background of this project and recent research works. The major reason for deterioration of concrete under irradiation conditions is expansion of aggregate due to neutron and gamma-ray irradiation. Dislocation of atoms in covalent structures of aggregate minerals, and resultant lattice constant change and alteration to amorphous phase are produced by fast neutrons. In addition, through electronic exertion, some energy deposition is accumulated as permanent distortion/strain in atomic structures. Other effects are also summarized. We plan to conduct a neutron irradiation test from May 2013. In selecting mix proportions and concrete components for the irradiation test program, sample size as a function of capsule size and gamma-heating, cement type, and aggregate size and type are determined based on preliminary experiments.
Temperature and Pressure Effects on Hydrogen Separation From Syngas
Authors: Leyko Aaron B. , Gupta Ashwani K.
Published: February 2014

Multi-component synthetic gas (syngas) mixtures produced from the gasification of coal, low grade fuel, wastes and biomass offers a novel source of hydrogen production. Gasification also eliminates much of the pollutant emissions from the combustion these fuels. Palladium based membranes present a promising method for extracting hydrogen from syngas. Experimental results are presented from a lab scale experimental facility. This facility was designed and built to examine various types of palladium and palladium alloy membranes used to harvest hydrogen from the syngas. The thin membranes (on the order of ∼12μm) examined were supported on porous stainless-steel. This study used a mixture of pure gasses, including hydrogen, nitrogen, and carbon dioxide, to simulate syngas of different compositions. The specific focus aimed to evaluate the role of the membrane operational temperature and pressure on the hydrogen separation efficiency. Results are reported at temperatures from 325°C to 400°C and pressures from 5 to 30 psig for various concentrations of hydrogen. Results showed permeation to increase by up to 33% with a 75°C increase in temperature. Moreover, permeation increased by over 50% with an increase in partial pressure of hydrogen by only 10 psi. These results reveal that pressure has a dominant influence on enhancing membrane permeability.
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.
A Natural Circulation Waste Heat Recovery System for High Temperature Gas-Cooled Reactor Used and/or Spent Fuel Tanks: Part I — Design Considerations and Theoretical Simulation
Authors: Senda Franck M. , Dobson Robert T.
Published: February 2014

This paper presents potential application of waste heat recovery (WHR) systems in high-temperature reactors technology. WHR systems have attracted the attention of many researchers over the past two decades, as using waste heat improves the system overall efficiency, notwithstanding the additional cost to upgrade the plant efficiency. WHR systems require specially designed heat recovery equipment, and as such the high-temperature gas-cooled reactor used and/or spent fuel tanks (SFTs) were considered by the way of example. An appropriately scaled system was designed and modelled to demonstrate the functioning of such a system, by the way of a cooling process of the used and/or SFT. Two separate and independent cooling lines, using a natural circulation flow in a particular form of heat pipes called thermosyphon loops were used to ensure that the fuel tank (FT) is cooled when the power conversion unit has to be switched off for maintenance, or if it fails. Assuming a one-dimensional flow model, a quasi-static and incompressible flow of both liquid and vapour, a theoretical model that simulates the heat transfer process in the as-designed WHR system is developed in this paper.
Effects of Hydrophobic Surface Patterning on Boiling Heat Transfer and Critical Heat Flux of Water at Atmospheric Pressure
Authors: Coyle Carolyn , O’Hanley Harry , Phillips Bren , Buongiorno Jacopo , McKrell Thomas
Published: February 2014

The effects of hydrophilic/hydrophobic surface patterning on critical heat flux (CHF) and heat transfer coefficient (HTC) were studied using custom-engineered testing surfaces. Patterning was created over a sapphire substrate and tested in a pool boiling facility in MITs Reactor Hydraulics Laboratory. The hydrophilic and hydrophobic matrices were created using layer by layer deposition of 50 nm thick SiO2 nanoparticles and monolayer thickness fluorosilane, respectively. Ultraviolet ozone patterning was then used with chrome-printed masks to create the desired geometric features. Hexagon, ring, star, and mixed patterns were tested to determine their abilities to affect CHF and HTC through prevention of bubble pinning at high heat fluxes. During testing, an infrared camera was used to measure the surface temperature distribution as well as locate nucleation sites for data analysis. It was found that CHF values were enhanced over the bare sapphire values by approximately 90% for hexagons, 60% for stars, 65% for rings, and 50% for mixed patterns. Contrary to expectations, patterning did not seem to affect the HTC values significantly. Although patterning did improve CHF performance over bare heaters, both CHF and HTC were found to be statistically similar to those for unpatterned, uniformly hydrophilic surfaces.
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.
Harmonic Impact Study for Distributed Energy Resources Integrated Into Power Distribution Networks
Authors: Arghandeh Reza , Onen Ahmet , Jung Jaesung , Cheng Danling , Broadwater Robert , Centeno Virgilio
Published: February 2014

Smart realization involves a steady increase in inverter-based components like Distributed Energy Resources (DER), energy storage systems, and plug-in electric vehicles. The harmonics related to DER inverters and the spread of power electronic devices raises concerns for utilities and customers. Harmonics can create component failures, thermal losses and control system malfunctions. In this paper the authors analyze the impact of multi-source harmonics from DERs inside distribution networks. The harmonics impacts are evaluated by harmonic measurement indices. Harmonic emission in a real distribution circuit is simulated with the help of power flow analysis. The results are presented with visualization techniques to give a better picture of harmonic propagation vs. different levels of harmonic source magnitude and angle. Due to effect of harmonic on network efficiency, a sensitivity analysis considering power factors is conducted.
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.