bluuebunny/crossref_metadata_2025 huggingface dataset:
Solids Level Indication in the Power Industry
Authors: Riley Keith
Published: January 2011

This paper will address technologies currently available to provide level indication in the Power Industry. In order to narrow the scope of our discussion we will limit the topic to both continuous and point level applications for solids. The principle behind each technology features and benefits as well as real world application examples will be presented.
Joint Integrity Monitoring Using Permanent Ultrasonic Bolt Load Transducers
Authors: Meisterling Jesse R.
Published: January 2011

Most bolts are designed as tension members, developing a compressive force in a joint (clamp load) that reacts against the external forces of the system: pressure, wind, shock, etc. The main objective of the assembly operation is the creation of the design tension force in the bolt. The degree of success in the assembly process has a direct relationship to the successful operation of the joint system in the field. Until today, the only convenient methods to determine bolt load in the field or on the production floor was to re-apply the tightening tool: wrench or tensioner. The application of the permanent metal/ceramic sputter deposited ultrasonic transducers on large, tension critical fasteners allows for bolt load measurement at any time. This technology delivers ultrasonic direct load measurement while removing all of the inconvenience and variability of conventional ultrasonic techniques. The thin film transducer is small: O̸ 3–5mm, inert, thin (<25um) and permanently attached to the fastener. It is an easy and convenient way to directly measure clamp load in a fastener during production, inspection and in the field: today, tomorrow and next year. The thin-film transducer can be used on a wider range of fastener sizes than possible with conventional hand-held transducers in long-term maintenance applications. The presentation will discuss ultrasonic bolt load measurement theory, and applications with case histories.
Errors Resulting From Excluding the Effects of Humidity on the Performance of Combustion Turbine Plants Equipped With Evaporative Coolers
Authors: Sasso John
Published: January 2011

Combustion turbine combined cycle (CTCC) plants have generally been the “power plant of choice” over the past two decades for a number of reasons, including first cost, efficiency, and low emissions. Combustion (Gas) turbine (CT) based plants now account for over 30% of the electric power capacity in the United States. Despite the significant reliance on this technology, the electric Independent System Operators (ISOs) have yet to recognize and acknowledge in their production templates, test forms and performance predicting software the Brayton Cycle limitations, most notably how humidity affects output for CT plants equipped with evaporative cooling systems. Such plants account for an estimated 48% of the CT power installed in the last 10 years. Ignoring the impact of humidity on these plants can lead to errors in production predictions beyond the normal tolerance band of 3% to as high as 9% during peak ambient temperatures for certain units. As such the electric ISO’s prediction of available generation and the associated capacity reserve margins have the potential to be overestimated. The article explores the situation in more depth, presents examples within the NYISO, quantifies the potential impact and recommends easy solutions to close the gap.
Boiler Feed Water Make-Up Upgrade With Integrated Membrane System: A Case Study
Authors: Farooq Khalid
Published: January 2011

A major Midwest US utility power station upgraded its boiler feed water make-up system by replacing the conventional lime softening and sand/gravel bed filtration with an integrated membrane based system. The conventional system was resulting in the use of large quantities of coagulant, lime, acid and caustic to produce demineralized water. The system, besides being expensive to operate, was unable to cope with the sudden changes in the incoming raw water quality from the nearby lake. The integrated membrane (IM) system, consisting of Microfiltration and Reverse Osmosis sub-systems, significantly improved the run time of the deep bed ion-exchange as well as the pre-coat condensate polishing system. As a result of the upgrade, the plant saw reduction of over 90% in the operating cost of the boiler feed water makeup system along with higher reliability and efficiency of the overall power plant. The paper discusses the experience and the lessons learned during the implementation of the IM system.
Conveyor Technologies for the Regulatory Environment
Authors: Bierie Greg , Mari Andy
Published: January 2011

The handling of coal is prone to problems including fugitive materials and flammable dusts. Now OSHA is increasing its attention to accumulations of flammable dusts in industrial plants. And other regulatory agencies are watching particulate emissions more carefully with an eye to environmental compliance and employee safety. It is therefore incumbent for plants to find ways to move materials without the problems that non-compliance with these regulatory agencies could create. Now there are a number of leading edge conveyor technologies that can help. These advanced systems are engineered to control material flow, and to prevent the escape of dust and the accumulation of fugitive material. Among these technologies are: engineered chutes, air-supported conveyors, and a “new generation” conveyor architecture. With their “engineered-in” methods for controlling fugitive material and improving employee safety, these world-class belt conveyor systems offer power generation facilities the best chance to successfully face the challenges of coal handling in a challenging 21st century regulatory environment.
A Liquid Torrefication Process for Producing a Storable, Energy-Dense Fuel From Biomass Feedstock
Authors: Watson Kyle A. , Stringfellow William T. , Pejack Edwin R. , Paoluccio John J. , Jain Ravi K.
Published: January 2011

This paper discusses a novel process for creating torrefied wood pellets by using a liquid torrefication process. Torrefication is a type of pyrolysis process originally developed for converting wood to an energy-dense material with properties similar to coal that would be more compact and practical to ship long distances and store outdoors. Torrefied wood has been used in specialized metallurgy and other industrial applications, but wide-scale utilization of torrefication for biofuel production has not been commercialized. Virtually all of the processing methods used in the past involve exposing biomass to hot, inert gas in an oxygen free environment; this gas-phase torrefication has a number of drawbacks, including a net-negative overall energy balance; generation of polluted gas that is difficult to treat or control; safety issues associated with the intrusion of oxygen into the inert gas; large equipment size and associated initial capital cost; operating cost; and manufacture of a nonuniform product. This paper discusses a technique that uses a heat treatment fluid in lieu of an inert gas which has numerous advantages over gas-phase torrefication and resolves many of the problems resulting from the commercial application of gasphase torrefication. This process for converting biomass to biofuel using a liquid-phase torrefication process is being developed under the trade name CNFbiofuel™ where CNF is an acronym for Carbon Neutral Fuel. The CNF Biofuel process has been developed on a small scale and results of preliminary testing are presented. Measurements of the energy content for the proposed biofuel process indicate an 18% increase in energy content for torrefied versus untreated wood pellets. Furthermore, the energy density measurements of these treated samples were also consistently higher than the untreated samples. Measurements have also been performed in order to measure the hydrophobic ability of the treated pellets and the results indicate that saturation with water has only a small effect on energy content. The heating value was determined to be reduced by only 2.2% on average after soaking in water for six hours and then being allowed to dry for 12 hours. The potential advantages of liquid-phase torrefication over any currently available gas-phase process are discussed.
Gas Turbine Gas Fuel Composition Performance Correction Using Wobbe Index
Authors: Li Bryan , Gross Mike J. , Schmitt Thomas P.
Published: January 2011

Gas turbine thermal performance is dependent on many external conditions, including fuel gas composition. Variations in composition cause changes in output and heat consumption during operation. Measured performance must be corrected to specified reference conditions prior to comparison against performance specifications. The fuel composition is one such condition for which performance corrections are required. The methodology of fuel composition corrections can take various forms. One current method of correction commonly used is to characterize fuel composition effects as a function of heating value and hydrogen-to-carbon ratio. This method has been used in the past within a limited range of fuel composition variation around the expected composition, yielding relatively small correction factors on the order of +/− 0.1%. Industry trends suggest that gas turbines will continue to be exposed to broader ranges of gas constituents, and the corresponding performance effects will be much larger. For example, liquefied natural gas, synthesized low BTU fuel, and bio fuels are becoming more common, with associated performance effects of +/− 0.5% or greater. As a result of these trends, performance test results will bear a greater dependency on fuel composition corrections. Hence, a more comprehensive correction methodology is required to encompass a broader range of fuel constituents encountered. Combustion system behavior, specifically emissions and flame stability, is also influenced by variations in fuel gas composition. The power generation industry uses Wobbe Index as an indicator of fuel composition. Wobbe Index relates the heating value of the fuel to its density. High variations in Wobbe Index can cause operability issues including combustion dynamics and increased emissions. A new method for performance corrections using Wobbe Index as the correlating fuel parameter has been considered. Analytical studies have been completed with the aid of thermodynamic models to identify the extent to which the Wobbe Index can be used to correlate the response of the gas turbine performance parameters to fuel gas composition. Results of the study presented in this paper suggest that improved performance test accuracy can be achieved by using Wobbe Index as a performance correction parameter, instead of the aforementioned conventional fuel characteristics. Furthermore, a relationship between this method’s accuracy and CO2 content of fuel is established such that an additional correction yields results with even better accuracy. This proposed method remains compliant with intent of internationally accepted test codes such as ASME PTC-22, ASME PTC-46, and ISO 2314.
Evaluating the Impact of the Uncertainty of Evaporative Cooler Effectiveness on the Net Power for a PTC 46 Test
Authors: Dooley Matthew J.
Published: January 2011

This paper discusses how relative humidity impacts the effectiveness of an evaporative cooler, the uncertainty of the calculated effectiveness and the corresponding impact of the limits of this uncertainty on the power output. This is particularly related to a combined cycle facility where performance guarantees are based upon the evaporative cooler being in service. Different options for testing with and without the evaporative cooler in service are discussed as well as the need for an uncertainty when using a K factor.
Integrating Regional Water Considerations Into Nuclear Plant Design
Authors: Scroggs Steven D. , Raffenberg Matthew J. , Flajole Andrew J.
Published: January 2011

Steam powered electrical generation, and nuclear generation in particular, requires significant water resources. Water resources throughout the world, and in many geographic areas in the United States, are challenged to meet environmental needs and the requirements of a steadily growing population including uses for the production of essential societal needs (food, hygiene, electricity). In Florida, ecosystem restoration is also recognized as a priority and places additional claims on a limited resource. Siting of a new nuclear generation facility in South Florida poses a considerable challenge, but also offers a unique opportunity. Florida Power & Light Company is proposing a new two unit AP-1000 project in southern Miami-Dade County that has included regional water issues in the conceptual design process. The project has selected reclaimed wastewater as its primary cooling water supply and, through specifically engineered mitigation projects, seeks to support regional ecosystem restoration projects. Disposition of power plant waste streams will be conducted by deep well injection, the first application of this established method for an operating nuclear facility. This paper identifies the design challenges presented by these regional issues and how they have been addressed by the engineering team.
Pressure Testing Feedwater Heaters and Power Plant Auxiliary Heat Exchangers
Authors: Yokell Stanley
Published: January 2011

This paper discusses factory and field pressure testing of tubular heat transfer equipment such as closed feedwater heaters, steam surface condensers and power plant auxiliary heat exchangers built to Section VIII Division 1 of the ASME Boiler and Pressure Vessel Code (the ASME Code) and repaired or altered in accordance with the National Board Inspection Code (NBIC). It discusses the ASME Code’s and the NBIC’s requirements for hydrostatically testing unfired pressure vessels which includes tubular heat transfer equipment. It points out that using pressure gage indications of pressure loss to determine if there is a leak from the tube side to the shell side when the back face of the tubesheet is not visible does not reveal very small leaks or weeping. For the purposes of this paper, we define weeping, VRRLeak, as a leak of 20 drops per hour or approximately 1 cm3 [0.061 in3]. During typical half-hour hydrostatic test pressure holding periods, such weeping would amount to 10 drops of water on the tubesheet face or 0.5 cm3 [0.0305 in3]. Weeping through tube-to-tubesheet joints of high-pressure feedwater heaters can lead to wire drawing (wormholing), which can materially reduce the heater life. Leaks from the channel to the shell side of steam surface condensers and auxiliary condensers can introduce brackish water into the condensate. Depending upon the fluid flowing in the tubes, contaminants can enter the shell side of other auxiliary equipment when the channel pressure is higher than that of the shell. The paper concludes that Users must advise Designers and Manufacturers of the hazards of small leaks through the tube-to-tubesheet joints. It recommends that these three entities must agree on suitable leak tests.
Turbine Improvements at Hoover Dam
Authors: Bruninga Bill
Published: January 2011

The Bureau of Reclamation is using advanced mechanical engineering design and project management techniques to regain power plant capacity lost as a result of drought-related low water levels at 2,074-MW Hoover Dam. Work includes mechanical modifications in 11 hydro turbine-generator units to increase flow rates as well as overhauling all 17 turbines. The mechanical modifications to date have recovered 84 MW with an annual value of $2.7 million. Additional power produced by the 11 units overhauled to date equates to nearly $3.2 million a year. In addition to advanced mechanical design and stainless steel fabrication based on computational fluid dynamics, this project is noted for tightly coordinated procurement and installation project management within an existing O&M program at an aging operational power plant.
Impact of Generator Rating Increase, Ambient Pressure and Coolant Composition and Temperature on Power Generator Heat Exchangers
Authors: Zea Luis P.
Published: January 2011

Heat exchangers’ operating requirements vary depending on several parameters such as plant location, coolant input conditions and generator total output power. Some of these parameters play a more important role than others and understanding these roles is key to designing heat exchangers that will better suit their operating conditions. This paper analytically examines the implications that varying four parameters have on a heat exchanger with a fixed geometry and heat transfer area. Ambient pressure decrease translates into changes on the thermodynamic conditions of the gas flow. Coolant composition variances (from condensate to increased glycol percentages) also play an important role on the exchanger’s heat transfer rates, the higher the glycol percentage the lower the heat transfer rate. In the same manner, the coolant inlet temperature will partly determine heat transfer rates. Lastly, a generator total output power increase will yield higher heat losses on several points of the generator and thus, a higher heat load for the heat exchanger. The graphs and data hereby presented should be of assistance to those designing new coolers as well as those operating current ones.
Study of the Heat Transfer in an Annular Combustor
Authors: Rami´rez-Barro´n A. , Gallegos-Mun˜oz A. , Riesco-A´vila J. M. , Marti´nez Marti´nez Simo´n
Published: January 2011

The study of the combustion in an annular combustor including the radiation heat transfer is presented. The study considers different models of combustion, the turbulence-chemistry interaction and the chemical kinetics. In the analysis a non-premixed, diffuse and turbulent model is considered, applying CFD (Fluent ®). The Chemical Equilibrium and Laminar Flamelet models are considered with one chemical mechanism to natural gas (methane). The results obtained show the radiation heat transfer effect on the temperature distribution in the combustor and compare the results obtained with both combustion models. The radiation heat transfer increases the temperature of the fuel and air input, modifying the temperature profile at the output of the combustor. On the other hand, the Laminar Flamelet model shows better results of temperature profiles at the output of the combustor, to be compared with results presenting in the literature.
Numerical-Experimental Study of the Gas LP Atmospheric Burner
Authors: Rami´rez-Barro´n A. , Aguilar-Moreno A. , Gallegos-Mun˜oz A. , Riesco-A´vila J. M. , Marti´nez-Marti´nez S. , Sa´nchez-Cruz F. A.
Published: January 2011

A numerical-experimental study of the gas LP atmospheric burner used in the ceramist furnace is presented. A new design of the burner was proposed to obtain a temperature distribution in the furnace better that the temperature distribution obtained with the actual burner. The experimental study helped to know the temperature and flame distribution in the furnace that permit to achieve the temperature of baking of the ceramic. The experimental results were obtained with a thermal camera and thermocouples placed in the furnace. Numerical models were developed with CFD (Fluent ®) comparing the results with the experimental results to obtain the new design of the burner. The experimental and numerical results permitted to identify the zones with temperature near to the temperature of baking, which is reached in the high and intermediate zones of the furnace. Then it is necessary a recirculation of the hot gases toward the low zone of the furnace.
The Effect of Nitrogen in Natural Gas on the NOx Emission From a 90 kW Burner
Authors: Diego-Marin Antonio , Melendez-Cervantes Carlos , Mani Gonzalez Alejandro
Published: January 2011

The role of different levels of nitrogen in natural gas on the emissions of NOx was investigated in a furnace. Nitrogen was added to the natural gas in concentrations of 4, 7 and 11% by volume. In addition, a trial was carried out as a baseline with 0.17% N2. The thermal load of the furnace was 90 kW and was kept constant in all four trials. Flue gas temperatures were measured with a small suction pyrometer, as well as incident heat flux with an ellipsoidal radiometer. In addition, flue gas composition was conducted at the stack of the experimental furnace. NOx emissions decreased as nitrogen was added to natural gas. This was due to the reduction of flue gas temperature near the burner zone where the thermal mechanism can play a significant role. With 11% nitrogen in natural gas, the flue gas temperature and the incident heat flux near the burner were the lowest, but the highest at the furnace exit. Therefore, care should be taken to avoid damages in gas turbines or furnaces while burning natural gas with high nitrogen content.
Auxiliary Ventilation Systems Design Basis and Analysis Approach
Authors: Douglass Stuart R.
Published: January 2011

Auxiliary systems supporting pressurized water reactors (PWR) within commercial nuclear power plants are enclosed within a special ventilation (SV) zone that is isolated post-accident. Air within the SV zone is recirculated through carbon adsorbers, and discharged at a rate equal to the SV zone air infiltration rate. The SV zone relies on safety-related fan coil units (FCUs) to remove heat since air infiltration is kept to a minimum in order to reduce the spread of contamination. This paper discusses efforts undertaken to quantify area heat loads and FCU operating conditions within the SV zone, and transient analyses performed for loss of FCUs using the GOTHIC code.
Successful Replacement of a Condemned HP/IP Turbine by Weld Process
Authors: Parham Damien , Davis Calvin
Published: January 2011

During the summer of 2008, a power plant performed a routine maintenance outage and discovered two cracks in the bore of their HP/IP rotor. The customer worked with the OEM to investigate the cracks in the rotor. The OEM recommended the following: perform a bottle-bore procedure, perform mechanical integrity calculations, and manufacture a new rotor in parallel. The duration of this repair would take over 24 months to complete. Alstom was contacted by the customer to supply repair recommendations. After an inspection of the unit and the boresonic data, Alstom proposed manufacturing a new replacement with a shorter lead-time. The process would involve join welding two stock forgings and adding some additional weld build up. The customer selected Alstom’s proposal, which could provide a replacement rotor in six months. The work scope included: join welding two rotor forgings together, shaft weld build up, extensive machining, and in parallel the manufacturing and installation 17 rows of turbine blades. This paper will discuss and document the case of the condemned HP/IP rotor.
CFD Analysis of Composite Axial Water Turbine
Authors: Wang Jifeng , Mu¨ller Norbert
Published: January 2011

This paper presents computational investigation of the flow in composite material axial water turbines using Finite Volume based commercial CFD package namely Fluent. Based on three dimensional numerical flow analysis and fluid-structure interaction, the flow characteristics of water turbines including nozzle, impeller and diffuser are predicted. Two particulare cases are studied and compared. The extract power of water turbine in different rotating speed and water inlet velocity are analyzed. The calculated results will provide a fundamental understanding of the impeller as water turbine, and this design method is used to shorten the design period and improve the water turbine’s performance.
Degradation Trending of Boiler Evaporator Tubes Without Scaffolding
Authors: Boxma Coen , Noteboom Jan Willem , Kraijesteijn Joop
Published: January 2011

Inspection of wall thickness of the evaporator walls is usually performed from the inside of the boiler with standard ultrasonic (UT) spot testing. The costs for this type of inspection is largely determined by the cost for scaffolding and grinding and by safety measures which sometimes even include radiation control. The necessity for grinding also slightly impacts the accuracy of the readings. A new non-destructive testing application has been developed which provides the possibility to do this inspection from the outside of a boiler and thus eliminating the need for scaffolding. Windows of interest of about 10 to 120 ft2 are selected and provisions in the boiler insulation are made. The tubes in the selected areas are tested through UT scanning. The minimum wall thickness of each tube in that window is graphically presented in a report and repeat measurements enable the plant owner to compare these values in time. Trends in wall thickness reduction provide a basis for boiler life time prediction and to take preventive action. As a tool for preinspection to assess required maintenance measures (such as overlay welding or tube replacement), this test application has already shown to be very valuable. Recent applications include wall thickness assessment of refractory covered wall tubes, testing of boiler wall tubing with internal wall thickness loss at the fire sided tube face and wall thickness assessment of Inconel clad tubes at waste incinerators (EU project: NextGen Biowaste). This paper will discuss the method of non-destructive testing of wall thickness of the evaporator walls from the outside and will present examples where this method is applied.
Experimental and Theoretical Study on the Aerodynamic Performance of a Small Horizontal Axis Wind Turbine
Authors: Refan Maryam , Hangan Horia
Published: January 2011

An upwind, three-bladed small horizontal axis wind turbine (HAWT) with a rotor of 2.2 m in diameter is tested in the Boundary Layer Wind Tunnel Laboratory II (BLWTL II). The power output of the turbine is measured for free stream velocities ranging from 1 m/s to 9 m/s. The blade element momentum (BEM) theory is implemented to predict the power curve of the HAWT. The theoretical characteristics of the turbine are discussed in terms of power and torque coefficients and the experimental results are compared to the numerical (BEM) estimation. Moreover, a force balance test is carried out on a single stationary blade for 16 angles of incidence, −6°≤α′≤30°, and three free stream velocities, 5, 7 and 9 m/s, and integral blade aerodynamic coefficients are determined. These experimental characteristics are intended to provide a useful basis for developing an alternative computational method to use integral blade experimental aerodynamic data to predict the power curve of the wind turbine in the transition zone between dynamic stall and fully stalled regimes.
Circulating Water Pump Modifications Performed in Conjunction With Cooling Tower Replacement During a 35-Day Outage
Authors: Morgenstern Robert M.
Published: January 2011

Westar Lawrence Energy Center Unit 5 in Lawrence, Kansas is a 375 mW unit that utilized a closed loop circulating water system with a wooden cooling tower and three horizontal circulating water pumps to provide cooling water to the condenser. The wooden cooling tower experienced rapid degradation over the past five years of operation. Chlorine was added to the water chemistry to reduce attack of the wooden components, but the chlorine levels in the water caused accelerated corrosion of the pump components and base plates. Circulating water system capacity was reduced due to worn pump components and excessive clearances. Unit load was limited by the lack of adequate circulating water capacity. This paper discusses the pump and motor repairs, design changes performed in parallel with demolition of the wooden cooling tower, and replacement with a new fiberglass tower designed to utilize the existing concrete basin. All of the changes were implemented during an outage in April-May 2009.
Design of a Cross Flow Turbine for a Micro-Hydro Power Application
Authors: Chattha Javed A. , Khan Mohammad S. , Wasif Syed T. , Ghani Osama A. , Zia Mohammad O. , Hamid Zohaib
Published: January 2011

The total installed capacity of the hydropower stations in Pakistan is about 7,000 MW which is about 20% of the total available hydro power potential. For possible micro-hydro stations, a potential of about 1300 MW exists at a number of low head and high flow rate sites. Work has been reported by Chattha et al. [1, 2] related to installation of a micro-hydro power station at one of the typical sites. An axial flow pump-as-turbine (PaT) was installed to generate electrical power at the micro-hydro station. The site selected for this work is quite typical and efforts are now being made to utilize the maximum potential of the site conditions. The PaT only utilizes about half of the available flow of water and a spillway was constructed at this site to divert the excess amount of water. The diverted water flows back to the main stream after bypassing the PaT. Work is now being carried out to explore the installation of a turbine in the spillway to harness the energy potential of the diverted water stream. This work includes selection, design, fabrication and installation of a turbine in order to generate electrical power utilizing the energy of water diverted to the spillway. A 100 ft3/sec flow rate with about 11 ft head is available at the spillway side. Considering these site conditions and indigenous fabrication expertise, cross flow type turbine has been selected for installation. Cross flow turbines are being manufactured in Pakistan and are usually quite successful for micro-hydro systems. Based on the available site conditions, a cross flow turbine has been designed. The diameter and length of the turbine runner have been calculated. Furthermore, the number of blades and radius of curvature have been determined along with other design parameters. The designed turbine is expected to produce about 50 kW of power. The complete design of the turbine, based on the available site conditions is presented in this paper.
Nuclear and Solar Energy: An Unexpected Alliance
Authors: Keller Michael F.
Published: January 2011

Hybrid-nuclear energy is an emerging and completely unexpected solution to the energy and climate change crises faced by our world. Because the hybrid is based on combined-cycle technology, an alliance with solar energy can be readily formed. The economies of scale associated with hybrid-nuclear energy allow the solar variant to achieve a competitive position in the power marketplace with no particular need to rely on on-going government subsidies.
Numerical Simulation and Experimental Study of a Two-Floor Structure Pumping System
Authors: Liu Chao , Jin Yan , Zhou Jiren , Tang Fangping
Published: January 2011

The two-floor flow passages pumping system with the simple structure is well practical in the Basin of Yangzi River downstream. However, this kind of pumping system has some disadvantages, such as low efficiency, easy to appear submerse vortex in discharge flow passages which causes the unit vibration and does harm to the operating of pump unit. In order to solve these problems, the design scheme with a new curve of diffusing outlet structure and inlet cone put forward, which are used in the renovation of the two-floor flow passages pumping station. With the numerical simulation of the two-floor flow passages pumping system, the flow fields are analyzed, and the external performance curves are obtained. To verify the calculation, a model tests were done using the standard model of pump. The test results are compared with the performance curves of numerical simulation. Good agreement of two results is found in the high efficiency area, which can show the calculation is believable. The new design improves the efficiency of pumping system significantly and eliminates the submerse vortex, also can guarantees the economy and security of operating.
NETL Virtual Reality Dynamic Simulation Research and Training Center Promotes IGCC Technology With CO2 Capture
Authors: Provost Graham T. , Zitney Stephen E. , Turton Richard A. , Erbes Michael R. , Stone Herman P.
Published: January 2011

To meet increasing demand for education and experience with commercial-scale, coal-fired, integrated gasification combined cycle (IGCC) plants with CO2 capture, the Department of Energy’s (DOE) National Energy Technology Laboratory (NETL) is leading a project to deploy a generic, full-scope, real-time IGCC dynamic plant simulator for use in establishing a world-class research and training center, and to promote and demonstrate IGCC technology to power industry personnel. The simulator, being built by Invensys Process Systems (IOM), will be installed at two separate sites, at NETL and West Virginia University (WVU), and will combine a process/gasification simulator with a power/combined-cycle simulator together in a single dynamic simulation framework for use in engineering research studies and training applications. The simulator, scheduled to be launched in mid-year 2010, will have the following capabilities: • High-fidelity, dynamic model of process-side (gasification and gas cleaning with CO2 capture) and power-block-side (combined cycle) for a generic IGCC plant fueled by coal and/or petroleum coke. • A fully integrated virtual reality Immersive Training System which allows for training of field personnel using a full scale three dimensional IGCC plant environment that is tied to the simulation and emulated DCS. • Highly flexible configuration that allows concurrent training on separate gasification and combined cycle simulators, or up to two IGCC simulators. • Ability to enhance and modify the plant model to facilitate studies of changes in plant configuration, equipment, and control strategies to support future R&D efforts. • Training capabilities including startup, shutdown, load following and shedding, response to fuel and ambient condition variations, control strategy analysis (turbine vs. gasifier lead, etc.), representative malfunctions/trips, alarms, scenarios, trending, snapshots, data historian, etc.
A Case Study on Generation of Acceptance Criteria in Feedwater Supply Tube Bends
Authors: Peters Daniel T. , Jones Eric
Published: January 2011

Inspection of components utilizing advanced examination techniques is becoming standard practice in the power industry. One of the critical aspects during this type of inspection is to have on hand criteria for acceptance or rejection of flaws found during these inspections. The examinations typically include the use of advanced ultrasonic techniques such as Linear Phased Array (LPA), Focused Annular Phased Array (APA), and Time of Flight Diffraction. These techniques can detect and size flaws that are often “Fit for Service” for at least one additional outage cycle. However, schedule limitations during an outage often do not permit for extensive analysis time. Repair decisions need to be made immediately and having criteria available for these decisions are critical. The following is a case study for the generation of acceptance / rejection criteria for power boiler feedwater supply tube bends. The determination of “allowable flaw sizes” is needed to determine which of these supply tube bends need to be removed during the outage. The acceptance criteria in this work is based on the criteria of API 579-1 / ASME FFS-1 “Fitness for Service Standard” [1] to evaluate the rate of growth of the flaws found. Discussion is also made as to the sensitivity of the examination methods used to detect the flaws expected and how this relates to the acceptance criteria generated.
Heat Recovery From Tail Gas Incineration to Generate Power
Authors: Tawfik Tarek A. , Smith Thomas P.
Published: January 2011

Many industrial processes result in tail gas wastes that must be flared or incinerated to abide with environmental guidelines. Tail gas incineration occurs in several chemical processes resulting in high-temperature exhaust gas that simply go to the stack, thus wasting all that valuable heat! This paper discusses useful heat recovery and electric power generation utilizing available heat in exhaust gas from tail gas incinerators. Tail gas, which is considered as the main fuel in this study, is typically “free” fuel. Eventhough with low heat content, when the heat is recovered and utilized properly, heat recovery of tail gas will result in significant savings to the plant. The thermodynamic and economic study presented here assumes that heat will be recovered in a wast-heat recovery boiler from the exhaust gas out of the incinerator and will produce enough superheated steam to generate 25 MW in a condensing steam turbine generator. Data for this study were provided by an operating chemical production facility in the southeastern region of the US. Energy analysis and a total project scope cost estimate were developed for this study. Actual costs were obtained for all major equipment. Different thermodynamic scenarios were considered to identify the optimum and most economical energy system design. The main goal of the study was to fulfill the plant’s power and steam requirements and sell the additional power to the local utility. An existing old steam boiler will be retired after the incorporation of the new cogeneration plant. Process steam will be supplied via a steam turbine extraction. The results indicate that the total capital cost of a ± 25% grade estimate for the supply and installation of the 25 MW cogeneration system, is estimated to be $51,000,000 in the fourth quarter of 2008 dollars with escalation through end of 2010, representing $2000/kW. Based on an internal power demand of 12 MW by the chemical plant, a balance of 13 MW is assumed be sold to the local utility. The cost of electricity used for this study was assumed to be 9 cents per kilowatt-hour for purchased power and 6 cents per kilowatt-hour for sold power. The annual plant savings in purchased power is estimated to be over $6,300,000 while the annual plant revenue from selling the remaining power is estimated to be in excess of $6,200,000. The cost analysis, when accounting for operation and maintenance, resulted in a pay back period of less than 4 years and an internal rate of return on investment of over 13 percent after 6 years.
Determining Steam Turbine Inspection Intervals
Authors: Reed Douglas D.
Published: January 2011

Steam turbine maintenance intervals have been extended from the Original Equipment Manufacturers’ (OEM) recommended intervals over the last 20 years. Inspections in which the casing is completely opened have been pushed to 10 years or longer on units with OEM recommended intervals of 5 to 6 years. This has been made possible because of additional data monitoring and in place inspection techniques which allow the internal condition of the unit to be assessed without opening the casing. Risk-based computer modeling and analysis techniques have allowed us to predict safe extended component inspection intervals using fracture mechanics. This paper gives a systematic approach to determining the condition of a steam turbine based on past history and current measured parameters. It provides a discussion of the effects of changes to components and how to determine and rank risk factors. Also discussed are results of inspections of machines which have been opened after extended intervals.
Investigation on the Performance of the 15kW OTEC System
Authors: Gong Jianying , Gao Tieyu
Published: January 2011

In the paper, the performance of two cycle systems, Rankine and Kalina-11 (KSC-11) are compared. The conclusion of this comparison yields the Kalina-11 cycle superior. In the KSC-11 cycle, it is found that the optimal ammonia fraction exists in the system under a fixed turbine inlet pressure. And the corresponding optimal turbine exists in the system under a constant ammonia fraction. When the ocean temperature difference is 19°C, the ammonia fraction has little effect on the 15kW OTEC KSC-11 system maximal net power with the corresponding optimal turbine inlet pressure of 0.6∼0.75MPa. When the ammonia fraction is 0.95, the system has the best combined performance. And the corresponding optimal turbine inlet pressure is revealed to be 0.75MPa. The ratio of total heat exchanger area to net power produced γ is discovered to be 6∼7 m2/kW.
An Experience With ASME PTC-70 Ramp Rates
Authors: Toburen Tina L.
Published: January 2011

ASME PTC-70 is a new performance test code for determination of ramp rates. Ramp rates are often required by dispatch agencies and independent system operators (ISOs). They are used to ensure the reliability of the electric power grid to ensure enough available power is achievable in the time frame required — for instance, if any generating unit suddenly comes offline, the remaining units online at that time will need to pick up the required load. A mix of both spinning reserve and non-spinning reserve may be needed. The published ramp rates declared by the generating units along with available reserve power are used by system operators to balance the potential for lost generation due to scheduled, expected and emergency events. An ASME committee was formed late in 2007 to develop PTC 70 after it was determined that there was no standard methodology to determine ramp rates in the US. Just over one year later, PTC 70 was sent to publishing, and is now available for use by industry. Published in 2009, the amount of experience with PTC 70 is limited. One such experience is described here, including setup, testing and results of the ramp rate test at a dual LM6000 simple cycle facility.
Extrapolation of Creep Curve and Creep Life Prediction From Secondary Creep by Evaluation of Strain Rate Change
Authors: Sato Hiroyuki
Published: January 2011

New method of creep life prediction by Strain-Acceleration-Parameter, SAP, is presented. Sato has found that shapes of creep curves can be characterized by the SAP that reflects magnitude of strain-rate change in secondary creep [1–4]. The SAP values are defined at minimum creep rates, and show the shapes of a creep curve, that depends on stress and temperature. Reconstruction of creep curves by a combination of SAP and a minimum-creep rate is successfully performed, and the extrapolated curves agree well with experiment. The predicted life times also reasonably agree with that obtained by experiment. The possibility of precise life prediction by SAP is pronounced. One of an important advantage of the proposed method is that the required parameters evaluated by individual creep curve are simpler than that are used in methods previously proposed, i.e., the theta projection concept, for example. Possibilities of wide application on many kinds of heat resistant materials should be investigated with the method of SAP.
Gasification: Eliminating Risks Associated With Co-Firing Biomass
Authors: Paskach Thomas J. , Reardon John P.
Published: January 2011

Under certain greenhouse gas (GHG) regulation scenarios, older coal-fired units may be faced with the prospect of shutdown before reaching the end of their useful life. Repurposing this existing asset for 100% biomass fuel is a more efficient use of capital than compared to building a new stand-alone unit. Biomass co-firing is an alternative for an owner to consider to address GHG regulation impacts on older coal-fired power boilers and the growing demands of pending legislation. “Direct” co-firing is a baseline approach where finely divided biomass is injected directly into the boiler furnace. Direct co-firing experience is typically less than 5% heat rate, and technical upper limits have been described in EPRI literature (1) as approximately 10% of boiler heat. Direct co-firing also does not enhance the opportunity to co-fire biomass with natural gas. Direct biomass co-firing may require extensive renovations and emissions/particulate control devices. “Indirect” co-firing is an alternative process that mitigates process risk by first converting the biomass into a fuel gas and then cleaning this gas to remove alkali and chloride contaminants prior to combustion in the power boiler furnace. Indirect co-firing may be a superior approach from an operations perspective because it protects against forced outages and repair costs expected with direct co-firing (2). Gas cleaning to remove alkali metals from the fuel gas prior to combustion reduces process risk by reducing fouling and slagging potential. Removing chloride from the fuel gas dramatically reduces the corrosion potential. Beyond reducing process risk, separating biomass ash before combustion retains the value in separate co-product ash streams, as it prevents intermingling with the coal ash. This paper describes technical and economic considerations for indirect co-firing, contrasted with direct co-firing approaches. The renewable energy ratio of a co-fired unit could be significantly increased by employing biomass gasification of the solid fuel with gas cleanup, in contrast to process risks, added emissions control costs, and technical limitations of direct co-firing of the solid biofuel.
Critical Uncertainties and Probabilities: Heat Impact on Exhaust System Components—A Case Study
Authors: Ciras Joseph R. , Green Michael G.
Published: January 2011

This paper addresses an issue with gas turbine manifolds. The manifolds were developing cracks once the exhaust gas output properties were changed. Exhaust gas velocities and temperatures have increased as the gas turbine efficiency increased putting thermal strain into the system. One of the other effects of the increase in gas turbine flow was the introduction of flow induced vibrations into the system. The source of the vibration will not be addressed in this paper and will be investigated in the future. Data for this case study was gathered at various gas turbine sites throughout the United States, either first hand or by representation. Site photos were taken, field reports were written, and a field fix was developed by a gas turbine system component Original Equipment Manufacturer (OEM). This fix has been working and the OEM had asked for analytical data to determine its reliability. Principle used to determine Critical Uncertainties and Probabilities (CUP) on the system were engineering Computation Tools, Algorithms, Methodologies, and Engineering Interpretation (CAME). The principles of CUP and CAME are being further developed my Mr. Ciras and Prof. Mustapha S. Fofana at Worcester Polytechnic Institute in Worcester, MA. The principles of six sigma, axiomatic design, and lean manufacturing were used as techniques to evaluate and valuate the most suitable solution to this problem. For this case study, the entire system around the fault area was looked at and analyzed. The system is composed of the turbine inlet, the gas turbine and its mounting system, the exhaust manifold, the exhaust diffuser, and the Heat Recovery Steam Generators (HRSG) along with interacting components within the system. CUP was use on each system component to determine with certainty what was causing the failures to prove the reliability of the field fix established by the OEM. The solution to this issue was established by suggesting proper manufacturing techniques; such as welding, material selection, allowance for thermal growth, proper installation of the external installation, proper fastening methods for the external installation and suggestions for improvements in the other system components. The proof was completed and the reliability of the fix relies heavily on the interaction of the system components in the area of the manifold.
Human Tears Contain a Chemosignal
Authors: Gelstein Shani , Yeshurun Yaara , Rozenkrantz Liron , Shushan Sagit , Frumin Idan , Roth Yehudah , Sobel Noam
Published: January 2011

Merely sniffing women's negative emotional tears reduces sexual arousal in men.
Seismic Detection of the Lunar Core
Authors: Weber Renee C. , Lin Pei-Ying , Garnero Edward J. , Williams Quentin , Lognonné Philippe
Published: January 2011

Reinterpreted Apollo-era seismic data from the Moon reveal a solid inner core and a fluid outer core.
A Persistent Oxygen Anomaly Reveals the Fate of Spilled Methane in the Deep Gulf of Mexico
Authors: Kessler John D. , Valentine David L. , Redmond Molly C. , Du Mengran , Chan Eric W. , Mendes Stephanie D. , Quiroz Erik W. , Villanueva Christie J. , Shusta Stephani S. , Werra Lindsay M. , Yvon-Lewis Shari A. , Weber Thomas C.
Published: January 2011

Methane released during the Deepwater Horizon blowout was degraded by methanotrophic bacteria.