The Advantages of Using Multiple Frequencies for Eddy Current Examination of Condenser Tubing

An essential element in the eddy current testing methodology is the use of multiple testing frequencies. A true volumetric inspection requires complete penetration of the tube wall from various perspectives. Since prime frequency is set to approximately thirty seven percent standard depth of penetration of the tube wall, additional frequencies are required to gain an accurate and detailed perspective of the defect. In fact, the need for additional frequencies is absolutely necessary to characterize particular defects such as under-deposit corrosion and microbiologically influenced corrosion. In such cases a minimum of three frequencies are required to perform optimum testing. The frequencies will vary from low, midrange to high depending on the material under test. A fourth frequency can also be used to identify tube supports and tubesheets. This paper demonstrates the effects and advantages of utilizing multiple frequencies in the testing process. The result of which is to provide the analyst with sufficient information to call the defects with greater accuracy and reliability. Utilizing a multi-frequency test instrument and standard probes commonly used for testing condenser tubes, tube samples with various defects will be examined utilizing one, two, three and four frequencies. Defect acquisition rates will also be varied and the results reported. The information is useful for determining the number of frequencies required for an effective eddy current test.

Estimating Long Term Major Maintenance and Capital Spending Requirements of Trinidad’s Aging Power Plants

This paper describes the process used by the Power Generation Company of Trinidad and Tobago (PowerGen) to estimate the range of major (expenditures greater than US$50,000) recurring and non-recurring costs that can be expected to be incurred from 2006–2025 by PowerGen’s three existing generating facilities: Port of Spain, Point Lisas and Penal. Since many of these Capital and O&M costs are not 100% certain, a probabilistic approach was used that incorporates a Monte Carlo methodology. The results of this approach allowed PowerGen to better understand the range of possible major capital and O&M expenditures that would likely be required over the next 20 years along with a quantification of the risk profile of those ranges. By adding these costs to the routine O&M costs, a total cost cash flow timeline was able to be developed that more realistically forecast the actual financial requirements of PowerGen’s power plants. Periodic review and updates of the data will also provide PowerGen with a continuing sound basis for long term technical and financial decisions. Additionally, a benchmarking analysis was performed that compared the reliability trends of similar but older technologies to those plants in PowerGen’s fleet in order to gain an insight into the reliability expectations for PowerGen plants over the next twenty years.

Investigation Into Optimal Operation of BCHP Systems in the Air-Conditioning Season

Building cooling, heating and power generation (BCHP) is important for the sustainable energy strategy in China because of its contribution to energy conservation and the reduction of CO2 emissions. The number of BCHP or small-scaled combined cooling, heating and power generation systems that have been put to use or are in the course of construction is steadily increasing in China. However, in many cases the performance of BCHP systems is not good enough, i.e., the average real exergetic efficiency of whole system is much lower than expected and the economic effect is not satisfactory. This is a problem that perplexes designers and plant owners and need be investigated so as to increase the knowledge of optimizing the operation of BCHP systems. In this paper the performance of a typical BCHP system is investigated using thermodynamic and thermoeconomic analyses based on the simulating results of off-design operation and the solution of performance optimization of the system. With the help of a great number of real running data of the system and the master data supplied by manufacturers, a model of the system operation is developed to simulate the whole domain of operation on off-design conditions. In order to shorten computer time the operation domain is described by a set of functions obtained by curve fitting using the numerical data from the simulation. Two models of optimization, of which the objective functions are the exergetic efficiency and gross benefit of the whole BCHP system separately, are established in virtue of these fitted functions. The simulation of off-design operation and the solution of the optimization problems supply a great number of useful data that form various graphs, which are to be the references to energy conservation and economic operation of the systems. The investigation indicates that there are some differences between the optimum working conditions obtained by the two optimization models, whereas it is inevitable that the system runs with some lower efficiency and less gross benefit when working at high cooling or heating load factors. By analyzing the data some significant conclusions are obtained, which will be helpful for the BCHP industry in China.

Solar Photovoltaic Water Pumping to Alleviate Drought in Remote Locations

Many parts of the western US is rural in nature and consequently do not have electrical distribution lines in many parts of farms and ranches. Distribution line extension costs can run from $15,000 to $25,000 per mile, thereby making availability of electricity to small water pumping projects economically unattractive. Solar photo-voltaic (PV) powered water pumping is more cost effective in these small scale applications. Many western states including Wyoming are passing through fifth year of drought with the consequent shortages of water for many applications. Wyoming State Climatologist is predicting a possible 5–10 years of drought. Drought impacts the surface water right away, while it takes much longer to impact the underground aquifers. To mitigate the effect on the livestock and wildlife, Wyoming Governor Dave Freudenthal initiated a solar water pumping initiative in cooperation with the University of Wyoming, County Conservation Districts, Rural Electric Cooperatives, and ranching organizations. Solar water pumping has several advantages over traditional systems; for example, diesel or propane engines require not only expensive fuels, they also create noise and air pollution in many remote pristine areas. Solar systems are environment friendly, low maintenance and have no fuel cost. In this paper the design, installation and performance monitoring of the solar system for small scale remote water pumping will be presented.

Models for Simulation and Diagnosis of Energy Plant Components

This paper describes a methodology to set up models for simulation and diagnosis of energy plant components. The adopted approach consists in a simultaneous solution of modules representing plant components taking their actual behavior into account. Models are characterized by Reality Functions to adapt them to the reality of machines and apparatuses so that the New&Clean map of the real component can be established. Furthermore, to account for deterioration phenomena occurring during plant operations, Actuality Functions affecting component performance in terms of work and heat transfer, losses and effective flow functions have been introduced. Models have been validated and tested against real CHP plant data. Two applications to different kinds of power plants are presented and discussed. Results show a good capability to estimate component deterioration statuses and reproduce component actual behavior maps.

Diagnostic Techniques for Improving Power Plant Performance, Reliability and Availability: A Case Study

The objectives of an effective power plant performance monitoring program are several-fold. They include: (a) assessing the overall condition of the plant through use of parameters such as output and heat rate (b) monitoring the health of individual components such as the steam generator, turbine-generator, feedwater heaters, moisture separators/reheaters (nuclear), condenser, cooling towers, pumps, etc. (c) using the results of the program to diagnose the causes for deviations in performance (d) quantifying the performance losses (e) taking timely and cost-effective corrective actions (f) using feedback techniques and incorporating lessons learned to institute preventive actions and, (g) optimizing performance. For the plant owner, the ultimate goals are improved plant availability and reliability and reduced cost of generation. The ability to succeed depends upon a number of factors such as cost, commitment, resources, performance monitoring tools, instrumentation, training, etc. Using a case study, this paper discusses diagnostic techniques that might aid power plants in improving their performance, reliability and availability. These techniques include performance parameters, supporting/refuting matrices, logic trees and decision trees for the overall plant as well as for individual components.

Turning NGCC Into IGCC: Cycle Retrofitting Issues

The increase in price of natural gas and the need for a cleaner technology to generate electricity has motivated the power industry to move towards Integrated Gasification Combined Cycle (IGCC) plants. The system uses a low heating value fuel such as coal or biomass that is gasified to produce a mixture of hydrogen and carbon monoxide. The potential for efficiency improvement and the decrease in emissions resulting from this process compared to coal-fired power plants are strong evidence to the argument that IGCC technology will be a key player in the future of power generation. In addition to new IGCC plants, and as a result of new emissions regulations, industry is looking at possibilities for retrofitting existing natural gas plants. This paper studies the feasibility of retrofitting existing gas turbines of Natural Gas Combined Cycle (NGCC) power plants to burn syngas, with a focus on the water/steam cycle design limitations and necessary changes. It shows how the gasification island processes can be treated independently and then integrated with the power block to make retrofitting possible. This paper provides a starting point to incorporate the gasification technology to current natural gas plants with minor redesigns.

Lessons Learned for Combustion Turbine Power Projects

Lessons Learned have long been used to refine designs and work practices. In recent years, litigation has caused this effort to be reviewed in terms of worth versus liability. Even the best-managed Lessons Learned program can have a negative impact to a company’s bottom line. This paper is intended to promote the beneficial rewards of, without regard for liabilities associated with, “Lessons Learned”.

Fast Pyrolysis of Distillated Ashe Juniper Biomass

Ashe Juniper is one of three major species of juniper native to Texas. Communities of Ashe Juniper occupy over 8 million acres of Texas rangelands and are responsible for herbage reduction, which adversely impacts the livestock carrying capacity. Ashe Juniper wood contains aromatic liquids called essential oils, which are economically beneficial for the personal care products industry. In order to exploit this benefit Texarome, Inc. of Leaky, Texas uses a large-scale steam distillation process to extract aromatic liquids from Ashe Juniper. This process results in a large quantity of Ashe Juniper woodchip waste for which there is few uses. A moderate temperature process known as fast pyrolysis was used to convert steam-distillated Ashe Juniper into a liquid known as bio-oil. An average liquid yield of 40.8% is reported for steam-distillated Ashe Juniper biomass and an average liquid yield of 47.3% is reported Ashe Juniper biomass that has not undergone the steam distillation process. This work demonstrates that the energy content of steam distillated Ashe Juniper can be extracted and the conversion to bio-oil is another potential use for Ashe Juniper woodchip waste. An economic model of Ashe Juniper biomass developed previously by Jua´rez and Daugaard was used to examine the economic impact of steam-distilled Ashe Juniper by simulating a 4,046-hectare (10,000 acre) Ashe Juniper energy plantation. It was found that bio-oil could be produced for as little as $5.20/GJ on a lower heating value basis if re-investment of profits made from the sale of essential oils extracted during the steam distillation process was assumed. Bio-oil from un-distillated Ashe Juniper could be produced for $13.21/GJ.

Advanced Nuclear Process Heat Concepts and Applications

This paper presents a summary of a screening study to select the most advantageous applications for nuclear process heat. The review is focused on the application of the Pebble Bed Modular Reactor (PBMR) technology adapted for process heat applications. This technology is unique in its smaller modular size and ability to deliver high temperature process heat at conditions that allow higher value applications. The implementation of projects for nuclear process heat and hydrogen production will require collaboration between nuclear power plant operators and process plant owners who will benefit from lower costs of heat delivery. Heat and hydrogen from nuclear water splitting can be used to displace expensive fuels, extend carbon utilization for products and reduce CO2 emissions and other environmental impacts.