Estimation of Performance Variation of Coal Fired Boilers Cofired With Biomass: Development of a Predicting Tool

Biomass cofiring in existing coal fired boilers has emerged as one of the most prospective technologies in order to address voluntary reduction of green house gases and other emissions, potential portfolio standards, customer service etc. within the context of deregulations. Pilot plant test results have confirmed the potential of biomass cofiring with coal for commercial use. However, being a new and developing technology, there is hardly any tool available for estimation of variation in performance of an existing coal fired boiler due to its retrofitting for biomass cofiring. A predicting tool is developed to estimate this performance variation using available information of pilot plant test results in literature or from data of plant operating with biomass. In order to incorporate future available information, this is developed in a flexible environment of Model Development Kit (MDK) of IPSEpro, a commercially available heat and mass balance program. Development of the models for this predicting tool as well as its limitations and possible future improvement has been discussed in this paper. Some results regarding estimation of change in efficiency, emissions and associated costs using this developed predicting tool has been presented.

Development of an In-Situ Laser Absorption NO/NO2 Measuring System for Gas Turbine Exhaust Jets

A diode-laser absorption system having the potential of simultaneous determination of NO and NO2 concentrations in the exhaust jets from gas turbines has been being developed. The sensitivities of the detection units at a typical exhaust gas temperature of 800 K were estimated as 30 ppmv-m and 3.7 ppmv-m for NO and NO2, respectively. Experiments using simulated exhaust gas flows have shown that CO2 do not have any interference with the NO and NO2 measurements. The detection limits in ppm of the system were considerably lowered by using a multi-pass optical system. A pair of off-axis parabola mirrors was useful to prevent the laser beam from straying from the detection area of the sensor due to the beam steering in the exhaust gas. Furthermore, the multi-path optical duct fabricated with 14 mirrors on the inner wall was effective in the measurement of NO and NO2 in the exhaust gas from gas turbines.

Using Diagnostics and Prognostics to Minimize the Cost of Ownership of Gas Turbines

In general, health management technologies observe features associated with anomalous system behavior and relate these features to useful information about the system’s condition. In the case of prognostics, this information is then related to the expected condition at some future time. The ability to estimate the time to conditional or to mechanical failure is of great benefit in health management systems. Inherently probabilistic in nature, prognostics can be applied to system/component failure modes governed by material condition and by functional loss. Like diagnostic algorithms, prognostic algorithms tend to be generic in design but specific in application. Today, elements of turbine gas generator condition based maintenance, module and part life analysis, and soft removal times play essential roles in sustaining safe operations and effective equipment maintenance. When intelligently combined with value chain analysis they provide the decision support system needed to undertake the maintenance actions which minimize total cost of ownership. The methodologies and mathematical constructs for performing optimization require the system designer to clearly define a useful cost or objective function, which when minimized mathematically produces the parametric design combination that we call optimized. In the specific cases where parametric constraints exist, our optimized system typically will be found along those boundary conditions.

Experience With GSP as a Gas Path Analysis Tool

SKF’s primary tool for gas turbine engine performance analysis is GSP (Gas turbine Simulation Program), a component based modeling environment that is developed at National Aerospace Laboratory NLR and Delft University of Technology, The Netherlands. One of the applications is gas path analysis (GPA) using GSP’s generic adaptive modeling capability. With GSP, gas path analysis has been applied to different aero engines at several maintenance facilities. Additional functionalities have been developed to analyze multiple engine operating points and combine results of different adaptive modeling configurations automatically, resulting in more accurate and reliable GPA results. A ‘multi-point calibration’ method for the reference model was developed providing a significant improvement of GPA accuracy and stability. Also, a method was developed using ‘multiple analysis cycles’ on different condition indicator subsets, which successfully generated values for all condition parameters in cases with fewer measurement parameters than condition indicators and where measurement data are unreliable. The method has been successfully demonstrated on the GEM42 turbo shaft engine. A number of case studies have shown GPA results corresponding to available maintenance notes and inspection data. The extension of the GSP GPA tool with a database system provides a useful tool for analyzing engine history and comparison of analyzed component conditions throughout the fleet. When a large amount of analysis data is stored in the database, statistic analyses, trending and data mining can be performed. Also maintenance work scope effect on engine performance can be predicted. In this paper, the newly developed GSP gas path analysis functionalities are described and experiences and results with the GEM42 engine operational environment are presented.

Advanced Materials for Mercury™ 50 Gas Turbine Combustion System

Solar Turbines Incorporated (Solar), under cooperative agreement number DE-FC26-00CH 11049, is improving the durability of gas turbine combustion systems while reducing life cycle costs. This project is part of the Advanced Materials in Advanced Industrial Gas Turbines program in DOE’s Office of Distributed Energy. The targeted engine is the Mercury™ 50 gas turbine, which was developed by Solar under the DOE Advanced Turbine Systems (ATS) program (DOE contract number DE-FC21-95MC31173). The ultimate goal of the program is to demonstrate a fully integrated Mercury 50 combustion system, modified with advanced materials technologies, at a host site for 4,000 hours. The program has focused on a dual path development route to define an optimum mix of technologies for the Mercury 50 turbine and future Solar products. For liner and injector development, multiple concepts including high thermal resistance thermal barrier coatings (TBC), oxide dispersion strengthened (ODS) alloys, continuous fiber ceramic composites (CFCC), and monolithic ceramics were evaluated. An advanced TBC system for the combustor was down-selected for field evaluation. ODS alloys were down-selected for the fuel injector tip application. Preliminary component and sub-scale testing was conducted to determine material properties and demonstrate proof-of-concept. Full-scale rig and engine testing were used to validate engine performance prior to field evaluation. Field evaluation of ceramic matrix composite liners in the Centaur® 50 gas turbine engine [1–3] which was previously conducted under the DOE sponsored Ceramic Stationary Gas Turbine program (DE-AC02-92CE40960), is continuing under this program. This paper is a status review of the program, detailing the current progress of the development and field evaluations.

Development of a Heavy Duty GT Syngas Burner for IGCC Power Plant in Order to Enlarge the GT Operating Conditions

In order to increase the fuel flexibility of the current design of the SynGas burner [4,5,6], Ansaldo Energia, since the growing requests of the market, performed a R&D financed project to use the SynGas fuel available as the unique fuel to feed the gas turbine. Therefore the new working condition to be fulfilled by the modified SynGas burner are the following: a) ignition; b) acceleration; c) loading at part load; d) change over from diffusion line to main SynGas line. To fulfill with new requirements, the standard V94.2K burners have been modified in order to operate from ignition up to the change over point with a SynGas mixture provided by the coal gasification process of a typical IGCC plant [7]. After the design phase, a experimental test campaign on the new design burner has been performed at atmospheric pressure. In order to validate the test results carried out at actual engine working conditions a further test campaign has been performed at the high pressure consistent with the test rig technical limitations [2.3]. The paper show the results carried out that are really promising to meet the customer requirements.

Understanding the Aftermarket: Applying Agent-Based Modelling to Service Infrastructure Design

In order to compete in challenging global markets, Rolls-Royce must have the capability to manage complex processes effectively. As the environment surrounding these processes is constantly changing, the ability to adapt to meet new requirements is essential. The challenge to the business is to quickly adopt an appropriate course of action for each set of circumstances, anticipated or otherwise. An individual decision-maker faced with this situation will normally have several options available. The difficulty is assessing the ramifications of each within a given time frame. To improve the quality of this evaluation, computerized decision support tools can be used. Such tools offer the ability to assess a multitude of options in a short space of time, using a combination of expert knowledge and real data. Having developed an extensive aero-engine service business, Rolls-Royce is required to maintain a highly dependable aftermarket infrastructure. Therefore, the ability to compare how any one particular aftermarket design would perform relative to another is an essential capability. Agent-based systems offer an approach that is both intuitive and interactive, modelling individual entities in the system from the bottom up, capturing low-level interactions that ultimately determine the overall performance of the system. This provides the flexibility and transparency to allow trustworthy analysis and evaluation to take place. To address this business need, an agent-based aftermarket model has been developed. An agent-based system is made up of small software programs built to operate just like a human team. Each agent has a set of capabilities and knowledge, but must work with other agents to achieve the overall goal. Agents can react to changes, adapting and re-planning if a better approach is identified. This paper describes how the model was constructed and the resulting analysis that it facilitates. The model has the ability to replicate the likely service characteristics that would be in place during the full lifecycle of the product. All aspects of the necessary infrastructure are captured, based upon the roles and capabilities of the constituent elements. Agents are used to represent a variety of objects and functions, including airports, airlines, aircraft, overhaul facilities and logistics. Through planning and negotiation, representative decisions are made by these agents to determine when an overhaul should take place and what the workscope should be based upon defined policies. A large selection of configurable parameters can be set by the user to accurately reflect the proposed scenario, providing a powerful what-if analysis tool that can be used to drive the design process, ensuring that product attributes and performance are aligned with the available maintenance infrastructure.

Fast Pyrolysis Oil for Power Generation

Biomass fast-pyrolysis oil (PO) is a liquid biofuel derived from lignocellulosic biomass: it offers several advantages compared to the direct us of solid bio fuels, such as high energy density, storability and transportability typical of liquid fuels, possibility to use the fuel in engines and turbines, easier downscaling of plants (which is a very important aspect for decentralized energy generation schemes). In addition, PO is the lowest cost biofuel, thus offering the possibility to penetrate also the large scale power generation market. Biomass POs have been studied and applications tested for many years, either for heat generation in medium-scale boilers or power generation. The present works reviews and analyses the most relevant experiences carried out so far and published results in power production from biomass PO. Power generation systems (PGS) which are here examined are gas turbines, diesel engines, stirling engines, as well as co-firing applications in large scale power plants (coal or natural gas plants). The main techniques for upgrading this biofuel and their impact on technologies are also shortly introduced and considered. The current status of development for each PO-based power generation option is discussed. This review work showed that long term demonstration (either technical or economical) is however still needed, even for the most developed technologies (use of PO in modified gas turbines and cofiring in natural gas stations): projects are on going to achieve long term demonstration.

Study on Efficient Hydrogen Production From Biomass

Hydrogen is crucial for the solution of future energy economy, and the development of mass and cheap production technology of hydrogen has become the central sector in overall hydrogen energy chain. For the abundance and renewability of biomass, it is of great potential to develop economically competitive and efficient biomass thermal conversion technology for hydrogen. One secondary decomposition process, combined with steam reforming, is proposed to the gaseous pyrolysis intermediate to promote hydrogen production. The method implements the sufficient utilization of hydrogen-containing components in biomass, while avoiding the influence of carbon towards the cracking of large molecule hydrocarbons. On the basis of self-energy-sustainability, hydrogen content in the product gas can be expected to reach 60 to 70 percent. From preliminary test on bench scale experimental system, hydrogen-rich gas with relatively small content of impunities was achieved, revealing the feasibility of the applied approach. The secondary decomposition of large molecule gaseous pyrolysis products and the steam reforming of some gas contents were proved to be effective in promoting the deep conversion of these components to hydrogen. When combined with efficent fuel cell system, the results of this work propose one prominent solution for the clean and local utilization of biomass.

Measurement of Flow Pattern Within a Rotating Stall Cell in an Axial Compressor

Effective active control of rotating stall in axial compressors requires detailed understanding of flow instabilities associated with this compressor regime. Newly designed miniature high frequency response total and static pressure probes as well as commercial thermoanemometric probes are suitable tools for this task. However, during the rotating stall cycle the probes are subjected to flow direction changes that are far larger than the range of probe incidence acceptance, and therefore probe data without a proper correction would misrepresent unsteady variations of flow parameters. A methodology, based on ensemble averaging, is proposed to circumvent this problem. In this approach the ensemble averaged signals acquired for various probe setting angles are segmented, and only the sections for probe setting angles close to the actual flow angle are used for signal recombination. The methodology was verified by excellent agreement between velocity distributions obtained from pressure probe data, and data measured with thermoanemometric probes. Vector plots of unsteady flow behavior during the rotating stall regime indicate reversed flow within the rotating stall cell that spreads over to adjacent rotor blade channels. Results of this study confirmed that the NASA Low Speed Axial Compressor (LSAC) while in a rotating stall regime at rotor design speed exhibits one stall cell that rotates at a speed equal to 50.6% of the rotor shaft speed.