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One of the main limiting factors when a green field pulp mill intends to increase its production is the capacity of the Tomlinson boiler by which the cooking chemicals are recovered. Since a boiler of this kind has a service life of some thirty years and represents a substantial investment, it is not an easy decision to replace it for a minor production increase. This study takes a novel approach to the problem. The excess black liquor is assumed to be recovered in a black liquor gasifier, an emerging technology for alternative black liquor recovery. Black liquor gasification in itself has been studied considerably during the last decade. In this study it is combined with the gasification of biomass, i.e. bark and wood, which is already available at a pulp mill. The resulting hybrid energy system, with a gas turbine and a gas expander, offers interesting possibilities: good off-design performance and high efficiency with respect to the fuel quality.Copyright © 1998 by ASME

The present paper describes the application of the exergy method to several power cycles of current interest in the Brazilian power scene. The ability of the exergy method to highlight component irreversibilities is of particular interest in this investigation. In this paper the exergy analysis for a simple gas turbine cycle, a combined gas/steam cycle, a combined gas/steam/freon cycle and a chemically recuperated gas turbine have been performed. As a yardstick for comparison a standard gas turbine engine with and without a steam bottoming cycle has been employed. The fuel considered is natural gas. The analysis of this system has been carried out using the exergy method. For the simple gas turbine cycle a biomass fuel has been employed as an alternative. The attraction of this fuel is its low impact on the environment and its plentiful supply in many regions in Brazil.

Biomass is a fuel of increasing interest in power generation since it is clean and renewable. Besides conventional power generating systems biomass fuel will be utilized in Integrated Gasification Combined Cycle (IGCC) power plants in the near future. Carbona Inc. (the successor to Enviropower Inc.) is commercializing a biomass fueled IGCC system. This system is based on a simplified IGCC process which applies the gasification technology originally developed by the Institute of Gas Technology (IGT) and further developed by Enviropower before licensing the technology to Carbona and an advanced hot gas clean-up system. An extensive pilot test program has been carried out by Enviropower/Carbona covering all aspects of a biomass based gasification process. More than 5000 tons of different biomass feedstocks have been gasified at the pilot plant in Tampere, Finland. The pilot plant converts 15 MW (51 MMBtu/h) thermal input of fuel to product gas. Several biomass qualities/mixtures have been used during the test runs including hard wood, soft wood with and without branches, needles and bark. Short rotation biomass like willow and alfalfa have also been tested. This paper concentrates on the results and differences in gasification of different biomass materials with special emphasis on the suitability of product gas for gas turbines, the fate of ammonia, vapor phase alkali metals and air toxics. The development of demonstration projects is also discussed in this paper.

This paper analyzes the fundamentals of IGCC power plants with carbon dioxide removal systems, by a cycle configuration alternative to the one discussed in Part A (with Oxygen-Blown Combustion). The idea behind this proposal is to overcome the major drawbacks of the previous solution (large oxygen consumption and re-design of the gas turbine unit), by means of a semiclosed cycle using air as the oxidizer. Consequently, combustion gases are largely diluted by nitrogen and cannot be simply compressed to produce liquefied CO2 for storage or disposal. However, CO2 concentration remains high enough to make separation possible by a physical absorption process. It requires a re-pressurization of the flow subtracted from the cycle, with relevant consequences on the plant energy balance. The configuration and the thermodynamic performance of this plant concept are extensively addressed in the paper. As in the first part, the influence of the pressure ratio is discussed, but values similar to the ones adopted in commercial heavy-duty machines provide here acceptable performance. Proper attention was paid to the impact of the absorption process on the energy consumption. The resulting net overall efficiency is again in the 38–39% range, with assumptions fully comparable to the ones of Part A. Finally, we demonstrated that the present scheme enables the use of unmodified machines, but large additional equipment is required for exhausts treatment and CO2 separation. A final comparison between the two semiclosed cycle concepts was therefore addressed.

This paper discusses the design and development program that is taking place to enable the availability in mid 1999 of a unit designated the Coberra 6761. This features the aircraft derivative Rolls-Royce RB211-24G upgrade gas generator and a new close coupled Cooper-Bessemer RT61 three stage power turbine. The paper describes the upgrade of the gas turbine from 28.4MW (38 000 SHP) to 31.8MW (42 600 SHP) ISO output power at over 40% thermal efficiency. Measures taken to maximize reliability and maintainability while reducing cost of ownership are described. The improvements in the gas generator compressors and turbines are detailed. The new design features of the power turbine are reviewed including a new support structure, modular service features and 3D orthogonal airfoil designs. The forthcoming validation program for the entire gas turbine unit is also discussed.

Computational Combustion Dynamics has been used extensively at General Electric Company for combustion applications. This paper demonstrates an application of Advanced Combustion Code to GE’s lean premixed dry low NOx emissions LM2500 and LM6000 gas turbine combustors. A methodology for anchoring the Double Annular Counter-Rotating Swirler (DACRS) exit conditions to Laser Doppler Velocity data from a reacting single cup experiment is described. The DACRS exit velocity profiles and turbulence parameters are inlet boundary conditions for the annular combustor simulation. Since over 80 per cent of the total air enters the combustor via the premixers, inaccuracies in these boundary conditions have a significant impact on the predicted flame shape, liner temperatures and emissions. The paper shows comparisons between measured and predicted velocity in a rectangular duct equipped with a single DACRS. The k-ε turbulence model and the two-step eddy break up/eddy dissipation combustion models are used to predict the reacting flow field of the natural gas/air flame. The inlet velocity profiles are developed first to match the LV data and the observed flame impingement location at nominal settings of the inlet turbulence parameters. The sum square error between measured and predicted velocity is used as the optimization function. Next, a design of experiment computational study is conducted to determine the inlet turbulence length scale and kinetic energy in order to further improve the data match. The eddy break up model is shown to be more robust than the eddy dissipation model. The eddy dissipation model resulted in slow combustion rates, and high fuel and carbon monoxide emissions.

An approach to improving the thermal cycle efficiency of combustion turbine (CT) based power plants is to develop thermal cycles with interceding, reheat, recuperation and humidification. Until recently, this was viewed by combustion turbine manufacturers as cost prohibitive and involving new operating and maintenance challenges. Also, early attempts by some manufacturers to develop sophisticated thermal cycles resulted in the realization that significant funds, personnel, and time are required. This investment could not be justified, particularly considering the availability of efficient and economical combined cycle (CC) plants.Therefore, increased efficiency for both simple and CC power plants has been achieved by raising the firing temperature and pressure of the basic Brayton cycle. However, every increase in the CT firing temperature required progressively higher development cost and increased NOx control challenges, which has re-awakened interest in advanced cycles.The Department of Energy’s Federal Energy Technology Center (FETC), in cooperation with combustion turbine manufacturers, is working on an Advanced Turbine Systems Program. The program goal is to develop technologies to provide a significant increase in natural gas-fired CC power generation plant efficiency with thermal efficiency target values in excess of 60%. Materials published in the program show that participating large CT original equipment manufacturers (OEM), are relying heavily on an increase in the CT’s firing temperature to approximately 2600 F (1700 K), with associated advancement in materials and cooling techniques, to achieve the target efficiency. Also employed are some improvements in component efficiency and various methods of utilization of heat in the bottoming cycle. The development of the necessary sophisticated materials and cooling techniques requires very significant development costs and is based on long duration and expensive experimental investigations and field demonstrations. Increasing the bottoming cycle efficiency primarily depends on the practicality of engineering solutions and capital vs operating cost trade-offs, and not on technology advancements.The current Cascaded Humidified Advanced Turbine (CHAT) technology, which utilizes existing, commercially proven combustion turbine and industrial hardware integrated in sophisticated thermal cycles, offers an achievable, practical and cost-effective alternative to a current CC plant. Current CHAT plants require relatively minimal engineering developments associated primarily with a) modification of the power shaft CT’s compressor discharge and turbine inlet plenums — for interfacing the HP shaft and other thermal cycle components — a very important engineering task, but not comparable in complexity to the development associated with further increase of the CT inlet temperature; and b) engineering of an HP expander with an inlet temperature of 1600 F (1145 K), essentially integrating steam turbine and industrial expander technologies.As it was shown collectively in the previously published references, in addition to an efficiency equal to that for CC plants (based on the same CTs), CHAT plants have significantly lower (10–20%) specific capital costs and have important operating advantages (higher than CC efficiency at part-load operation, with excellent load following and dynamic benefits, including rapid start capability). Those features reduce both the CHAT plant cost of electricity and offer a method to improve improve the economics of power generation systems due to the operational flexibility added by a CHAT plant.One of the most effective ways to increase the CHAT plant efficiency is to increase the HP expander inlet temperature from the current level of 1600 F (1145 K), which represents the level of the combustion turbine technology of the late 1960’s – early 1970’s. EPRI and ESPC have identified that a CHAT plant, based on the current combustion turbine technology (with turbine inlet temperature (TIT) of 2550 F (1670 K)), could achieve the ATS Program target efficiency of 60% with an HP expander inlet temperature of approximately 2000 F (1365 K). HP expanders with this relatively low turbine inlet temperature, as shown later, will require cooling of only the first stage nozzles and stage blades, if the newest single crystal alloys are used. However, the increase of the HP expander inlet temperature will be complicated by the relatively-high inlet pressure. This presents a significant engineering challenge, particularly if one would like to preserve the excellent start-up characteristics and other dynamic benefits of the CHAT plant.EPRI and ESPC are co-sponsoring the development of a high pressure expander with a target inlet temperature of 2000 F (1365 K). It will be shown that this HP expander, when integrated with a power shaft based on W 501 FA modified for the CHAT application, results in a power plant that will achieve the ATS Program target efficiency of 60%.This paper presents a) current CHAT plant’s performance and cost characteristics, b) findings of the project for the development of the HP expander with target temperature of 2000 F (1365 K), and c) a comparison of the advanced CHAT concept’s performance and development costs to those of the ATS program. This paper also shows how, in the future, the new ATS technology can be incorporated into even more efficient, cost-effective and reliable CHAT power plants.Copyright © 1997 by ASME

Lean premixed (LP) combustion is a proven concept for NOx-reduction in gas turbine systems. Lean premixed liquid fuel systems, also known as LPP (lean premixed prevaporized) systems, however, are more complex, as the fuel has to be atomized, evaporated and premixed prior to combustion and there is a higher risk of autoignition and coking. The Siemens LPP Hybrid burner, which was introduced into the Halmstadvaerket gas turbine of Sydkraft AB in Sweden in 1993, has since proven its reliability. As the primary design criteria have been maximum reliability and security against flashback, it still has a considerable potential for NOx-Emissions reduction. The objectives of this paper are to summarize the activities connected with the further development of the LPP Hybrid burner based on the Halmstadvaerket operation experience. These include the introduction of the LPP burner into a new machine generation with ring combustors as well as investigations into the two phase flow phenomena inside the burner. When the Model VX4.3A gas turbine family was introduced, the LPP Hybrid burner had to be scaled down to fit the different machine sizes. The paper reports on the development steps and first operation experiences with the LPP Hybrid burner system in HBR-combustor machines. In a concluding chapter, the paper outlines the next steps in the LPP development program. These include further experimental and numerical studies which are partly conducted in a co-operation between Sydkraft AB and Siemens AG.

Advanced prefilming airblast atomizers are widely used for low emission combustors since they deliver a fine spray almost independently of the fuel flow rate. The droplet spectrum produced by this type of atomizer results from the aerodynamic forces at the atomizer edge and from the fuel properties prior to the film disintegration. Therefore, the wall film temperature is an important parameter affecting the fuel properties and in turn the atomization quality. Even though this atomizer type became well investigated (Lefebvre 1989, Rizk et al. 1987, Sattelmayer et al. 1989), still no general quantitative relationship between atomizer design and spray quality could be established since the fuel state at the atomizer edge cannot be precisely predicted yet. In extending earlier experimental and theoretical work on airblast atomizers (Sattelmayer et al. 1989, Himmelsbach et al. 1994, Willmann et al. 1997) and recent advances in the numerical modeling of wall film flows (Rosskamp et al. 1997a), this paper presents a numerical approach to judge the effect of fuel mass flow, air flow and the film length (i. e. length of atomizer lip) on the temperature of the liquid at the atomizer edge. The computer code developed provides detailed information on the wall film flow and the nozzle wall temperature. For the prediction of heat transfer to the film a new model has been developed which is based on measurements of the internal film flow (Elsäßer et al 1997). This new numerical approach can serve as a design tool to evaluate the effects of design modifications during atomizer development with view to their effect on atomization performance. The paper includes the theory for two-phase flow modeling and a generic parameter study that points out that the liquid loading and the length of the atomizer lip are important parameters in atomizer design. The calculations presented in the paper emphasize the necessity of coupled two-phase flow calculations because the film strongly interacts with the gas phase and the predicted atomizer performance is sensitive to changes in the air flow.

The paper describes the experience gained in designing, developing and operation of gas turbine engines for gas pumping units on the marine gas turbine engine’s base. More than 800 Mashproekt gas turbines of various power output have been in service in gas pumping application since 1980. This paper shows the SPE Mashproekt designing and developing approach for gas turbines to be installed in gas pumping units along with their full-scale testing in the test bed of close gas loop type equipped with gas compressor and gas coolers to simulate operation of the gas pumping unit in the real gas pipeline conditions. The gas turbines for gas pumping application on the 2.5 MW, 6 MW, 10 MW, 16 MW and 25 MW engines base were developed in the period of 1990–1995 for replacement of the existing old gas turbine line-up and installation in the new gas pumping units at the compressor stations in Russia and Ukraine. We are replacing engines with Mashproekt gas turbines at the following gas pumping units: Russian GTN-25, Ukrainian GPA-6.3, GPA-16 and “Coberra-182” (Great Britain) gas pumping units. The comparison of the technical characteristics of these replacements is given in the paper. Technical data on 2.5–25 MW Mashproekt gas turbines for gas pumping units is also presented in this paper.

Many variants of the nuclear closed Brayton cycle (NCBC) power plant have been studied over the last five decades, the ultimate goal being the introduction of a high efficiency and environmentally acceptable plant for electrical power generation. With an indirect cycle (IDC) plant the thermal energy from a high temperature reactor (HTR) is transferred to the helium gas turbine power conversion system via an intermediate heat exchanger. Compared with previous direct cycle variants the decoupling of the prime-mover from the reactor has the following advantages, 1) configuration flexibility (eased congestion), 2) good component access, 3) non radioactive power conversion system, 4) ease of maintenance, 5) use of conventional equipment, 6) reduced development effort, and 7) eased adaptability to a fossil-fired source. In addition to being a more practical configuration, a major attribute for the IDC is that it is compatible with long-term plans for development of a high temperature nuclear heat source (NHS) currently underway in Japan. With a NHS in place a logical progression of the HTR would be to deploy a power generation version using an IDC helium gas turbine. This paper sheds new light on the nuclear gas turbine in that it is no longer at the forefront of gas cooled reactor application studies, but rather could be a beneficiary of work currently underway in Japan to develop a nuclear heat source for high temperature process heat. The performance and major features of a future NCBC plant concept are highlighted in this paper. Depending on the market forces prevailing in Asia for small nuclear plants, the NCBC with an indirect cycle helium gas turbine could be available for service around the year 2020.Copyright © 1996 by ASME

This paper has been written exactly 50 years after the first disclosure of a closed-cycle gas turbine concept with a simplistic uranium heater. Clearly, this plant was ahead of its time in terms of technology readiness, and the closed-cycle gas turbine was initially deployed in a cogeneration mode burning dirty fuels (e.g., coal, furnace gases). In the 1950s through the mid 1980s about 20 of these plants operated providing electrical power and district heating for European cities. The basic concept of a nuclear gas turbine plant was demonstrated in the USA on a small scale in 1961 with a mobile closed-cycle nitrogen gas turbine [330 KW(e)] coupled with a nuclear reactor. In the last three decades, closed-cycle gas turbine research and development, particularly in the U.S. has focused on space power systems, but today the utility size gas turbine-modular helium reactor (GT-MHR) is on the verge of being realized. The theme of this paper traces the half century of closed-cycle gas turbine evolution, and discusses the recent enabling technologies (e.g., magnetic bearings, compact recuperator) that now make the GT-MHR close to realization. The author would like to dedicate this paper to the late Professor Curt Keller who in 1935 filed the first closed-cycle gas turbine patent in Switzerland, and who exactly 50 years ago, first described a power plant involving the coupling of a helium gas turbine with a uranium heater.

This paper present results from a research program being conducted at the Advanced Combustion Engineering Research Center (ACERC) at Brigham Young University (BYU). This study is part of a comprehensive effort supported by the Advanced Gas Turbine Systems Research (ATS) Program headquartered at the South Carolina Energy Research and Development Center, Clemson, South Carolina. The objective of this study was to characterize a turbulent premixed propane/air flame in a model combustor that simulates the characteristics of a utility gas turbine engine. The program’s long term goal is to develop and commercialize ultra-high efficiency, environmentally superior, and cost competitive gas turbine systems for base-load applications in the utility, independent power producer, and industrial markets. This paper focuses on the following four areas of the investigation: 1) a series of digitized video images to document the effect of fuel equivalence ratio and swirl number on flame structure, 2) LDA velocity measurements to quantify the flow structure, 3) CARS gas temperature measurements to determine the temperature field in the combustor, and 4) local continuity and energy release in differential elements throughout the flame zone.

Externally fired gas turbines have the features of using solid fuel and requiring no particulate cleaning up to protect the gas turbine path. The solid fuel can be, for example, coal or biomass. Evaporative gas turbines (e.g., HAT cycle) have the potential to enhance the power output and increase the efficiency without including a bottoming steam turbine. The integration of the two systems, so called externally fired evaporative gas turbine, can offer the features from both of the systems. In the present paper, the modified externally fired evaporative cycle with intercooling and recuperation is proposed and analyzed. The externally fired gas turbine system is divided into three main subsystems: gas turbine subsystem, solid fuel combustion subsystem and heat recovery subsystem. This paper presents an in-depth investigation of the heat recovery subsystem and its impacts on the total system. The effects of intercooler and aftercooler on the whole system have been addressed and discussed. The optimization strategies for multiple interaction variables, such as air temperature after the recuperation, water-to-air ratio and combustion air temperature for the externally fired combustor, have been provided. The optimization results show that the behavior of the heat recovery subsystem greatly affects the cycle efficiency and power output. Using exhaust heat to heat humid air in a recuperator and to preheat combustion air to the biomass combustor are important for improving the externally fired evaporative gas turbine system. With the electrical efficiency as the objective function of the optimization, there exists an optimum water-to-air ratio located at 0.17 to 0.20 for the system studied in this paper.

The first part of this paper describes the test installation of the gas turbine and the compressor in the workshop, test execution, measuring methods, evaluation and measuring uncertainties. The second part of this paper describes the site installation, execution of the test under full load conditions on natural gas, measuring methods, evaluation and measuring uncertainties. The third part of this paper compares both the measurements and the Reynolds number correction which was used for the evaluation of the pipeline compressor test results in the workshop.

For closed-cycle gas turbines, in a size to meet utility power generation needs, the selection of helium as the working fluid represents the best solution in terms of the overall power conversion system considering the differing requirements of the turbomachinery and heat exchangers. Helium is well suited for the nuclear Brayton cycle because it is neutronically inert. The impact of helium’s unique properties on the performance and size of the power conversion system components is discussed in this paper. The helium gas turbine plants, that have operated were based on 1950s and 1960s technology, represent a valuable technology base in terms of practical experience gained. However, the design of the Gas Turbine Modular Helium Reactor (GT-MHR), which could see utility service in the first decade of the 21st century will utilize turbomachinery and heat exchanger technologies from the combustion gas turbine and aerospace industries. An understanding of how the design of power conversion systems for closed-cycle plants and combustion gas turbines are affected by the working fluids (i.e., helium and air, respectively) is the major theme of this paper.

A project team consisting of Foster Wheeler Development Corporation, Westinghouse Electric Corporation, Gilbert/Commonwealth and the Institute of Gas Technology, are developing a Second Generation Pressurized Fluidized Bed System. Foster Wheeler is developing a carbonizer (a partial gasifier) and a pressurized fluidized bed combustor. Both these units operate a nominal 1600°F (870°C) for optimal sulfur capture. Since this temperature is well below the current combustion turbine combustor outlet operating temperature of 2350°F (1290°C) to reach commercialization, a topping combustor and hot gas cleanup (HGCU) equipment must be developed. Westinghouse is participating in the development of the high temperature gas cleanup equipment and the topping combustor. This paper concentrates on the design and test of the topping combustor. The topping combustor in this cycle must utilize a low heating value syngas from the carbonizer at approximately 1600°F (870°C) and 150 to 210 psi (1.0 to 1.4 MPa). The syngas entering the topping combustor has been previously cleaned of particulates and alkali by the hot gas cleanup (HGCU) system. It also contains significant fuel bound nitrogen present as ammonia and other compounds. The fuel-bound nitrogen is significant because it will selectively convert to NOx if the fuel is burned under the highly oxidizing conditions of standard combustion turbine combustors. The fuel must be burned with the vitiated air from the pressurized fluidized bed combustor (PFBC). Oxidizer has been cleaned of particulates and alkali by HGCU system, and has also been partially depleted in oxygen. The 1600°F (870°C) oxidizer must also be utilized to cool the combustor as much as possible, though a small amount of compressor discharge air at a lower temperature 700°F (about 370°C) may be used. The application requirements indicate that a rich-quench-lean (RQL) combustor is necessary and the multi-annular swirl burner (MASB) was selected for further development. This paper provides an update on the development and testing of this MASB combustor. Additionally, Westinghouse has been conducting computational fluid dynamic (CFD) and chemical kinetic studies to assist in the design of the combustor and to help optimize the operation of the combustor. Results of these models are presented and compared to the test results.

A new, highly efficient 25-MW aero-derivative gas turbine, model FT8-55, has been developed for mechanical drive applications as a member of the FT8 gas turbine family which also includes two generator drive gas turbines, models FT8-30 and FT8-36, with power turbine speeds of 3000 rpm and 3600 rpm, respectively. For the new mechanical drive version FT8-55, the power turbine can be operated up to 5775 rpm at maximum continuous speed. All power turbines are equipped with gas generators, model GG8-1, which are derived from the most popular aero-engine in civil aviation, the JT8D. The first part of this paper describes design features, rotor dynamics, and material selection for the three-stage power turbine PT8-55. Rotor design permits unrestricted operation in the speed range from 2500 rpm up to maximum continuous speed. The first FT8-55 gas turbine was subjected to mechanical and performance workshop tests at different speeds and power outputs up to full-load. The second part of the paper deals with the description of the test stand arrangement for testing complete gas turbine packages as well as measurement techniques and data evaluation. Power was absorbed by a two-stage pipeline compressor, equipped with magnetic bearings and dry gas seals, which was operated in a closed loop. Thermodynamic and mechanical test results at various speeds and loads provide evidence of a highly efficient and mechanically robust gas turbine for mechanical drive applications.

This paper describes the first test of an industrial gas turbine and low emissions combustion system on coal-water-slurry fuel. The engine and combustion system have been developed over the past five years as part of the Heat Engines program sponsored by the Morgantown Energy Technology Center of the U.S. Department of Energy (DOE). The engine is a modified Allison 501-K industrial gas turbine designed to produce 3.5 MW of electrical power when burning natural gas or distillate fuel. Full load power output increases to approximately 4.9 MW when burning coal-water slurry as a result of additional turbine mass flow rate. The engine has been modified to accept an external staged combustion system developed specifically for burning coal and low quality ash-bearing fuels. Combustion staging permits the control of NOx from fuel-bound nitrogen while simultaneously controlling CO emissions. Water injection freezes molten ash in the quench zone located between the rich and lean zones. The dry ash is removed from the hot gas stream by two parallel cyclone separators. This paper describes the engine and combustor system modifications required for running on coal and presents the emissions and turbine performance data from the coal-water slurry testing. Included is a discussion of hot gas path ash deposition and planned future work that will support the commercialization of coal-fired gas turbines.

This paper describes the historical data for gas turbine driven compressor and power generation packages built for the North Sea. The period surveyed spans from the start-up of Ekofisk to the present day. The paper covers 60 platforms in the Norwegian and UK sectors and a number in the Danish and Dutch sectors. The data gathered for each platform include details of gas turbines, compressors, gearboxes, couplings, tube and seat oil systems, skid arrangements, air filtration systems, exhaust systems and so forth. In total, approximately 320 electric power generating sets and 380 compressors are included, representing 5.5 million kW. The trend over the survey period is found from the recorded data, and a comparison is made between the Norwegian and UK sectors.Copyright © 1992 by ASME

Two aspects of reliability assurance are discussed. First, This paper deals with the reliability design of the emissions under transient conditions. The optimization was made from the simulation results of the relationship between the response of the variable combustor geometry to follow load changes and the resulting exhaust emission levels. The load variation pattern used in this investigation was that of the Japanese 10-mode regulation. Second, this paper describes the validity of the reliability design prepared for the ceramic liner of the combustor. A service life prediction was made for the liner on the basis of stress analysis results and fatigue parameters.Copyright © 1992 by ASME

A pilot hot gas particulate removal system based on positive porous ceramic filters has been tested on the Grimethorpe Pressurized Fluidized Bed Combustor facility. The filters are in the form of closed ended tubes, 1.5 m long: these are generally called ‘candles’. The dust accumulates on the outside of the candles, and is periodically removed by a pulse of air into the candle interior, which then flows outwards through the candle wall in the reverse direction to the normal flow of the combustion gas. The EPRI system contained a maximum of 130 candles, which is approximately equivalent to the requirement for 7 MW(e) capacity, depending on the filter operating parameters. The filter unit operated for a total of 860 hours under PFBC conditions, of which 790 hours were at defined process conditions, typically 850°C and 10 bar. The amount of gas flowing through each filter element was varied, and the time between cleaning pulses was also varied. The pressure drop through each filter element rose as the dust accumulated on the outer wall, and recovered after the cleaning pulse. However, the post-cleaning pressure drop does not recover to the original clean candle value, but increases with time. It is believed that a steady-state value is attained, but the exposure in the Grimethorpe test series was insufficient to establish this unequivocally. During the test, five candles failed. This appears to have been due to mechanical shock, as a result of candles lifting because of excessive pressure differentials across their support plate, and dropping back. The failures are not believed to be intrinsic to the technology. However, in addition a reduction in the strength of the candles with time of exposure was observed. This might also attain a steady state value, but this too could not be established on the basis of the tests reported in this paper. This is clearly a matter of importance, and further work will be required to determine the suitability of the clay-bonded silicon carbide medium used in these tests for this application. A number of deficiencies in the design of the unit emerged with the operating experience, and suggestions have been made for improvements. However, it is clear that further work on design optimization is required. The pulse cleaning air usage in the tests was greater than would be economically acceptable in a practical system. Further work needs to be done to optimize the cleaning cycle. Overall, the test was very successful, and when operating properly the filters removed essentially all of the dust in the gas exiting from the combustor. Apart from the issues with the candle strength and the pulse cleaning air usage, the other problems were not believed to be of major importance in the further development of the technology. This paper will summarize the test results, emphasizing the problems of candle durability and the pulse cleaning system.

Stringent environmental constraints are usually associated with or applied to the siting and installation of new pipeline facilities. This has resulted in a significant portion of the design effort and ultimate cost of the facility to be dedicated to the mitigation of these environmental concerns. This paper describes how a compressor station can be designed and built such that stringent silencing requirements can be satisfied. The paper also references specific aspects of design which were successfully applied to the Parkway Compressor Station, Canada.Copyright © 1991 by ASME

Propulsion system definition to support emerging unmanned underwater vehicle (UUV) studies becomes of increasing significance as mission complexity grows. Substantial experience in the design of closed Brayton cycle (CBC) engines for marine applications has been applied to a range of UUV requirements and the results of system integration/conceptual design studies are described in this paper. The focus is on the heat engine; prior efforts have treated the associated thermochemical heat sources. Extensive use has been made of the pioneering efforts conducted 10 to 15 years ago. Some comparisons are given with competing propulsion system approaches (e.g., electrical systems), but these are not the focus of this paper since comparisons of this type have already been presented.Copyright © 1990 by ASME

Dynamic simulation of the operation of a compressor station requires mathematical modelling of the dynamic behaviour of the compressor unit and various piping elements. Such models consist of large systems of non-linear partial differential equations describing the pipe flow together with non-linear algebraic equations describing the quasi-steady flow through various valves, constrictions and compressors. In addition, the models also include mathematical descriptions of the control system which consists of mixed algebraic and ordinary differential (mad) equations with some inequalities representing controllers’ limits. In this paper a numerical technique for the solution of the gas dynamics equations is described, which is based on the transfer matrix formulation relating the state vector time-difference at one side of an element to that on the other side. This approach facilitates incorporation of all elements transfer matrices into an overall transfer matrix according to the system geometrical connectivity. The paper also presents simulation results and comparison with actual field measurements of three case histories: 1) simulation of a compressor surge protection control process; 2) unit startup; and 3) slow transient of a compressor station responding to changes in the discharge pressure set point. Good agreement between simulation results and field measurements is demonstrated.

With the capability of burning a variety of fossil fuels, giving high thermal efficiency, and operating with low emissions, the gas turbine is becoming a major prime-mover for a wide spectrum of applications. Almost three decades ago two experimental projects were undertaken in which gas turbines were actually operated with heat from nuclear reactors. In retrospect, these systems were ahead of their time in terms of technology readiness, and prospects of the practical coupling of a gas turbine with a nuclear heat source towards the realization of a high efficiency, pollutant free, dry-cooled power plant has remained a long-term goal, which has been periodically studied in the last twenty years. Technology advancements in both high temperature gas-cooled reactors, and gas turbines now make the concept of a nuclear gas turbine plant realizable. Two possible plant concepts are highlighted in this paper, (1) a direct cycle system involving the integration of a closed-cycle helium gas turbine with a modular high temperature gas cooled reactor (MHTGR), and (2) the utilization of a conventional and proven combined cycle gas turbine, again with the MHTGR, but now involving the use of secondary (helium) and tertiary (air) loops. The open cycle system is more equipment intensive and places demanding requirements on the very high temperature heat exchangers, but has the merit of being able to utilize a conventional combined cycle turbo-generator set. In this paper both power plant concepts are put into perspective in terms of categorizing the most suitable applications, highlighting their major features and characteristics, and identifying the technology requirements. The author would like to dedicate this paper to the late Professor Karl Bammert who actively supported deployment of the closed-cycle gas turbine for several decades with a variety of heat sources including fossil, solar, and nuclear systems.

Construction of the Borsig waste heat recovery system at NOVA’s Clearwater Compressor Station is now complete. Initial operation of the system has been very encouraging. This paper is an update on an earlier paper entitled “Pipeline Compressor Station with Waste Heat Recovery” by G. M. Holldorff, A. R. Hladun and S. A. Dunn. The process cycle including main components and control functions will be reviewed and their performance evaluated. Operating experience to date is also presented. In emphasizing safety, NOVA has instituted unique operating and maintenance procedures to this system. These procedures are also outlined.

This paper describes coal-fired, indirectly heated, air turbine combined cycle cogeneration plants that employ atmospheric pressure external combustion of coal, an open cycle gas (air) turbine, and a steam turbine. Air to operate the air turbine is heated indirectly, by hot fluidized solids contained inside tubes. The result is a high efficiency system that burns coal (or almost anything that will burn), does not require extensive operator training or support facilities, and emits low quantities of sulfur, NOx and particulates. The plant is capable of supplying electrical power, process heat, steam, and clean hot air in varying quantities, depending on the application. Uses exist in the chemical, petroleum, mining, metallurgical, paper, and textile industries and in enhanced oil recovery.Copyright © 1983 by ASME

In its gas transport system N.V. Nederlandse Gasunie found a shift from peak load to base load at stations which were not originally designed for that duty. A study was made of the application of recuperators on GE frame 5 gas turbines, based on experience with a prototype installation four years ago. The paper describes the Breda-regenerator in general and the experience of one of the two prototypes which was installed on a Gasunie frame 5 two shaft 24 mW gas turbine compressor unit in 1978. In June 1981 Gasunie decided to equip two more identical gas turbine compressor units at their 100,000 HP compressor station at Zweekhorst with Breda-regenerators. The paper covers all aspects of retrofitting the simple cycle gas turbine installations with regenerators at the Zweekhorst station.Copyright © 1983 by ASME

A gas turbine cogeneration system using a coal fired atmospheric fluid bed (AFB) combustor represents an environmentally clean and less costly alternative to the oil or gas fired electric power generators, process steam boilers and process heaters that are necessary for the operations of both small and large industrial energy users. This paper describes a cogeneration system which uses an air-to-gas heat exchanger tube assembly immersed in an AFB combustor to indirectly heat the compressor airflow from a gas turbine. This AFB combustor replaces the conventional direct fired oil or gas combustor. The flue gas from the AFB is used to produce steam and the waste energy from the gas turbine exhaust is used to provide additional steam or clean hot process air. By appropriate selection of components, AFB cogeneration systems can provide electrical-to-thermal ratios of 30 to 150 kilowatts per 1000 pounds of steam for a range of applications. The paper presents the key design features of this type of system. The selection of materials and mechanical configurations are presented. The status of the technology and the R&D supporting test results are discussed. Cogeneration applications are discussed.

The users of Gas Turbine powered equipment are very careful to ensure that they achieve their objectives in terms of power output and overall efficiency, but other important aspects of the system may be underspecified, and cause the user serviceability and maintenance problems during the systems planned operating life. One important area, crucial to reliable operation of the Gas Turbine, is the power turbine exhaust system. If particular care is not taken on the part of the user in specifying this component, he is likely to be provided with the minimum standard of equipment from the supplier. This paper highlights some of the areas that should be considered during the preparation of specifications, and in the evaluation of proposals. Specific problems of exhaust design will be addressed to assist the user to identify and question possible problem areas. The paper concludes that for minimal additional input during the initial stages of a project, long term cost savings could be made and that the overall system would be more reliable.

In the oil, gas and petrochemical industry, there are many instances where energy is under-utilized, if not actually wasted. In many cases it may be possible to recover some of this energy and obtain useful work, thereby improving plant efficiency and the economics of the operation. The turbo expander is a simple device that can make a significant contribution to the recovery of energy in all kinds of plants. This paper considers some ways in which turbo expanders may be used and looks in detail at an application in the gas industry where the energy lost in pressure reduction may be recovered and used to assist in reducing operating costs. The design criteria for such turbo expanders are discussed and areas for future development are proposed. The paper concludes that there are significant gains to be made in the recovery of waste energy and that the turbo expander can play a major role in this activity.

Water-cooled high temperature gas turbine technology has been under investigation by the Gas Turbine Division of the General Electric Company for the past 15 years. The transition from testing small scale laboratory-size hardware to full-scale gas turbine components was initiated in 1975 by General Electric and extended further under the U.S. Department of Energy’s High Temperature Turbine Technology (HTTT) Program. A key element in this transition was the identification of a composite (hybrid) design for the first-stage nozzles. This design permits efficient heat transfer to the water-cooling passage-ways, thus lowering effective strains and increasing part life. The results of GE’s extensive efforts over many years to develop a composite water-cooled first-stage nozzle were further confirmed through the successful fabrication and testing of full-scale hardware under the DOE/HTTT Program. This paper describes the post test metallurgical evaluation of two segments of the nozzle tested under the DOE/HTTT program. A brief description of the actual hot-gas path testing of the part is given. The bulk of the paper deals with a microstructural evaluation of the segments including microprobe traces and hardness surveys. Pre- and post-test non-destructive evaluations are also reviewed.

The installation and operation of an active magnetic bearing in conjunction with a modified mechanical dry gas seal on a natural gas pipeline compressor is presented. The emphasis of this paper is centered on the active magnetic bearing. The active magnetic bearing was developed by Société de Mécanique Magnétique (S2M) of Vernon France. The first successful application to a natural gas pipeline compressor was a co-operative effort between NOVA, AN ALBERTA CORPORATION, S2M, and Magnetic Bearing Incorporated (MBI) of Radford, Virginia. This paper represents a technical and economic assessment of the bearing, including installation and operational data.

A cogeneration plant based on a Combined Cycle (C.C.) system offers advantages especially when an in-expensive fuel can be used. Petroleum coke as a by-product solid fuel with high sulfur content can be fired in an Atmospheric Fluid Bed Combustion Air Heater (AFBC-AH) to provide indirect heating of the compressor discharge air flow of the gas turbine in such a C.C. system, which produces electric power and process steam in an efficient and environmentally clean manner. This paper describes (a) the overall system and some major components, (b) system performance and (c) the economics of such a plant for an application on a site, where petroleum Coke is already used as raw material in the industrial process. The paper shows that for this particular application the C.C. cogeneration plant with a petroleum coke fired AFB air heater can be competitive when compared with the natural gas or liquid fuel fired cogeneration plant. In addition, this plant will generate less emissions than generally achieved in solid fuel fired cogeneration plants.

Rocketdyne is under contract to DOE for the development of heat-exchanger technology that will allow coal to be burned for power generation and cogeneration applications. This effort involves both atmospheric fluidized bed and pulverized coal combustion systems. In addition, the heat-exchanger designs cover both metallic and ceramic materials for high temperature operations. This paper reports on the laboratory and small AFB test results completed to date. It also covers the design and installation of a 6 × 6 ft-atmospheric fluidized bed test facility being used to correlate and expand the knowledge gained from the initial tests. The paper concludes by showing the direction this technology is taking and outlining the steps to follow in subsequent programs.

The Norwegian Offshore Market has shown itself to be a market leader in introducing new requirements and technological innovations in the gas turbine packages used on new installations. This paper will review the changes that Altair Norge A/S has been a party to in the areas of “acoustics”, “reduction in pressure losses”, “reductions in weight”,” and an overall effort to reduce the “costs”. The systems effected by the above changes are Inlets, Ventilation, Enclosures, and Exhausts. The time span of this review is from 1981 to the present; with the emphasis on the last 5 years. It will be shown how the requirements generated by the authorities to protect the employees offshore generate benefits technologically.

The next civil supersonic aircraft project will pose a number of challenges. The propulsion system for this aircraft will have to achieve economic operation for both supersonic and subsonic regime while meeting the intended noise and pollutant emissions regulation. Whilst there are a number of proposed engines for the next generation civil supersonic aircraft, they all exhibit difficulties inherent in the engine duty. The present paper offers a simple solution based on retractable fans. The key for the success of the concept is the single stage double pass tip turbine that drives the fan. Characteristics of this unique turbine such as extra-high power output at reasonable efficiencies and low metal temperatures along with some performance aspects of the power plant are discussed. Although further investigation is still required, the performance of the system merits consideration. The work was undertaken by one of the authors as part of his MSc research project.Copyright © 1998 by ASME

While natural gas is achieving unrivalled penetration in the power generation sector, especially in gas-turbine combined cycles (CCGT), an increasing number of alternative fuels are in a position to take up the ground left vacant by this major primary energy. In particular, within the thriving family of liquid fuels, the class of volatile products opens interesting prospects for clean and efficient power generation in CCGT plants. Therefore, it has become a necessity for the gas turbine industry to extensively evaluate such new fuel candidates, among which: naphtha’s; kerosines; gas condensates; Natural Gas Liquids (NGL) and alcohols are the most prominent representatives. From a technical standpoint, the success of such projects requires both a careful approach to several specific issues (eg: fuel handling & storage, operation safety) and a clear identification of technological limits. For instance, while the purity of gas condensates meets the requirements of heavy-duty technologies, it generally appears unsuitable for aeroderivative machines. This paper offers a succinct but comprehensive technical approach and overviews some experience acquired in this area with heavy duty gas turbines. Its aim is to inform gas turbine users/engineers and project developers who envisage volatile fuels as alternative primary energies in gas turbine plants.

This paper investigates the layout and achievable efficiencies of rotating components of a Helium gas turbine. This is done by making a preliminary design of the compressor and turbine needed for the power conversion in a combined heat and power plant with a 40 MWth nuclear high temperature reactor as a heat source. State of the art efficiency values of air breathing gas turbines are used for the first calculations. The efficiency level is corrected by comparing various dimensionless data of the Helium turbomachine with an air gas turbine of similar dimensions. A single shaft configuration with a high speed axial turbine will give highest performance and simple construction. If a generator has to be driven at a conventional speed, a free power turbine configuration must be chosen. The choice of the configuration depends among others on the cost and availability of the asynchrone generator and frequency convertor.

The Department of Energy’s Federal Energy Technology Center (FETC) is sponsoring the Combustion 2000 Program aimed at introducing clean and more efficient advanced technology coal-based power systems in the early 21st century. As part of this program, the United Technologies Research Center has assembled a seven member team to identify and develop the technology for a High Performance Power Systems (HIPPS) that will provide in the near term, 47% efficiency (HHV), and meet emission goals only one-tenth of current New Source Performance Standards for coal-fired power plants. In addition, the team is identifying advanced technologies that could result in HIPPS with efficiencies approaching 55% (HHV). The HIPPS is a combined cycle that uses a coal-fired High Temperature Advanced Furnace (HITAF) to preheat compressor discharge air in both convective and radiant heaters. The heated air is then sent to the gas turbine where additional fuel, either natural gas or distillate, is burned to raise the temperature to the levels of modern gas turbines. Steam is raised in the HITAF and in a Heat Recovery Steam Generator for the steam bottoming cycle. With state-of-the-art frame type gas turbines, the efficiency goal of 47% is met in a system with more than two-thirds of the heat input furnished by coal. By using advanced aeroderivative engine technology, HIPPS in combined-cycle and Humid Air Turbine (HAT) cycle configurations could result in efficiencies of over 50% and could approach 55%. The following paper contains descriptions of the HIPPS concept including the HITAF and heat exchangers, and of the various gas turbine configurations. Projections of HIPPS performance, emissions including significant reduction in greenhouse gases are given. Application of HIPPS to repowering is discussed.

This paper reports an experimental investigation on centrifugal compressor surge. The compression system consists of a four-stage blower with vaned diffusers and a large plenum discharging into the atmosphere through a throttle valve. Measurements of unsteady pressure and flow rate in the plant, and of instantaneous velocity in the diffusers of the first and fourth compressor stage are performed during deep surge, at several valve settings and three different rotation speeds. Additional tests have been carried out on a different system configuration, i.e., without plenum, in order to obtain the steady-state compressor characteristics and to collect reference data on stall in surge-free conditions. In this configuration, a fully developed rotating stall was detected in the compressor diffusers, while during surge it affects only a limited part of the surge cycle. The goal of the present experimental work was to get a deeper insight into unstable operating conditions of multi-stage centrifugal compressors and to validate a theoretical model of the system instability to be used for the design of dynamic control systems.

Steam injection is a well-known principle for increasing gas turbine efficiency by taking advantage of the relatively high gas turbine exhaust temperatures. Unfortunately, performance is not sufficiently improved compared with alternative bottoming cycles. However, previously investigated supplements to the STIG-principle — such as sequential combustion and consideration of a back pressure steam turbine — led to a remarkable increase in efficiency. The cycle presented in this paper includes a further improvement: The steam, which exits from the back pressure steam turbine at a rather low temperature, is no longer led directly into the combustion chamber. Instead, it reenters the boiler to be further superheated. This modification yields additional improvement of the thermal efficiency due to a significant reduction of fuel consumption. Taking into account the simpler design compared with combined-cycle power plants, the described type of an advanced STIG-cycle (A-STIG) could represent an interesting alternative regarding peak and medium load power plants.Copyright © 1998 by ASME

With the advent of today’s dry low emission (DLE) combustors for industrial gas turbines (GT), an additional type of load case other than thermal loading on the combustor structure, has put itself heavily into focus, namely pulsation loading. Although recognised for decades in rocket engines and ram-jets, it was not until the incorporation of diluted flames and completely closed combustors, used to reduce NOx emissions, that thermo-acoustically excited pressure pulsations became an issue in the design of industrial GT combustors. This paper presents the computational methods that are available for the analysis of this phenomenon, and their application in the development of ABB’s latest annular DLE combustor. Among these are calculations of burner excitation frequency, pressure wave propagation within the combustor, acoustic and structural eigen frequencies, and coupled acoustic structural analysis. Guidelines for the combustor design to prevent instabilities and coupling of air and structure pulsations are suggested.

Sawmills in the Canadian province of British Columbia (BC) will soon be confronted with a collective wood waste disposal problem (bark, sawdust and shavings) of about 3 Million bone dry tonne/y at an average wet basis moisture content of about 45%. About 40 existing sawmill beehive burners presently incinerate this waste. Emissions from these beehive burners exceed current provincial particulate limits. Markets for the waste — board plants, sawdust digesters, charcoal plants, etc. — are limited. The economics of 25 to 50 MW wood-fired, steam power plants is poor. 6¢/kW.h is needed to finance a plant; the major utility offers 2¢/kW.h. This paper describes a 3 MW to 5 MW, Nuovo Pignone PGT-5 co-generation plant fuelled by the 2000°F (1093°C) exhaust from a Heuristic EnvirOcycler, a two-stage, wood waste incinerator. The exhaust meets BC’s particulate limit of 0.052 grains/dscf (120 mg/Nm3). 37 to 65 Million Btu/h (39 to 68 GJ/h) of waste heat can be recovered from the system exhausts. In this application the PGT-5’s external combustion chamber is replaced by a “recuperator”, i.e., a high temperature, gas-to-air, heat exchanger. Two variations of the basic system are examined. One features a larger than necessary EnvirOcycler to generate additional steam in the waste heat boiler. The other variation discusses heating 1,550°F (843°C) air from the recuperator up to 1,796°F (980°C) with natural gas. The extra power generated can cost as little as 1.9¢/kW.h.

The power-speed requirements of warships and the poor part load efficiency of simple cycle gas turbines has given rise to the design of many ship installations where two types of gas turbines are used. A large type for high speed, at full power, and a small one for cruise. It is common to mount two units of each type. This design results in a large amount of bulky and heavy ducting, much more voluminous and heavy than the gas turbines themselves. The present paper outlines an investigation into a novel intercooled split-cycle with some deck mounted components. This reduces the requirement for internal ducts in the ships hull, essentially, to those needed by the cruise engine. The engine performance has been predicted and a comparison is carried out between a traditional installation and the one investigated. An estimate has been carried out of the flow conditions of the duct to assess the change in losses for operation in the cruise and the full power condition. The new scheme appears to be promising.

A novel fuel-air mixing technique on the basis of vortex generators has been developed and successfully implemented in the worlds first lean-premix reheat combustor of ABB’s GT24/GT26 series industrial gas turbines. This technique uses a special arrangement of delta-wing type vortex generators to achieve rapid mixing through longitudinal vortices, which produce low pressure drop and no recirculation zones along the mixing section. In this paper, after a short introduction to the topic, the motivation for utilizing vortex generators and the main considerations in their design are explained. A detailed analysis of the flow field, pressure drop and the strength of the vortices generated by a single vortex generator are presented as one of the three main geometrical parameters is varied. The results obtained through water model tests indicate that an optimum vortex generator geometry exists, which produces the maximum circulation at a relatively low pressure drop price. Moreover, the axial velocity distribution along the mixing section stays uniform enough to assure flash-back free operation despite the elevated inlet temperatures encountered in a reheat combustor. After selecting this optimized geometry, the process of the arrangement of multiple vortex generators in an annular combustor segment is described. The optimum arrangement presented here is suitable both for gaseous and liquid fuel injection, since it requires only one injection location per combustor segment.Copyright © 1998 by ASME

The Brazilian Wood Biomass Demonstration Project (WBP) Phase II was contracted with the United Nations Development Programme - PNUD, Setor Comerical Norte, Quadra 2 - BLOCO A, EDF.Corporation-7° Andar, Brasilia - DF Brasil 70712-900 and General Electric Marine & Industrial Engines to develop the gas turbine equipment necessary to utilize fuel produced by the gasification of wood products. The program included performance studies, control specification requirements, bleed and fuel valve specifications, a modified dual gas fuel nozzle for fuel delivery to the combustor and results of two (2) combustor component tests utilizing biomass simulated fuel. This paper will deal primarily with the fuel nozzle design elements, the setup and evaluation of the component combustor tests and resulting emissions produced by the simulated Biomass fuel. Details of the combustor test arrangement, facilities and special test equipment needed to complete the evaluation will be presented. In addition, background on the two types of combustor testing will be discussed.Copyright © 1998 by ASME

Combustion dynamics (or combustion oscillations) have emerged as a significant consideration in the development of low-emission gas turbines. To date, the effect of premix fuel nozzle geometry on combustion dynamics has not been well-documented. This paper presents experimental stability data from several different fuel nozzle geometries (i.e., changing the axial position of fuel injection in the premixer, and considering simultaneous injection from two axial positions). Tests are conducted in a can-style combustor designed specifically to study combustion dynamics. The operating pressure is fixed at 7.5 atmospheres and the inlet air temperature is fixed at 588K (600F). Tests are conducted with a nominal heat input of 1MWth (3MBTUH). Equivalence ratio and nozzle reference velocity are varied over the ranges typical of premix combustor design. The fuel is natural gas. Results show that observed dynamics can be understood from a time-lag model for oscillations, but the presence of multiple acoustic modes in this combustor makes it difficult to achieve stable combustion by simply re-locating the point of fuel injection. In contrast, reduced oscillating pressure amplitude was observed at most test conditions using simultaneous fuel injection from two axial positions.Copyright © 1998 by ASME

Alternative fuel projects often require substantial amounts of oxygen. World scale gas-to-liquids (GTL) processes based on the partial oxidation of natural gas, followed by Fischer-Tropsch chemistry and product upgrading, may require in excess of 10,000 tons per day of pressurized oxygen. The remote location of many of these proposed projects and the availability of low-cost natural gas and byproduct steam from the GTL process disadvantages the use of traditional, motor-driven air separation units in favor of steam or gas turbine drive facilities. Another process of current interest is the partial oxidation of waste materials in industrial areas to generate synthesis gas. Synthesis gas may be processed into fuels and chemicals, or combusted in gas turbines to produce electricity. A key to the economic viability of such oxygen-based processes is cost effective air separation units, and the manner in which they are integrated with the rest of the facility. Because the trade-off between capital and energy is different for the remote gas and the industrial locations, the optimum integration schemes can also differ significantly. This paper examines various methods of integrating unit operations to improve the economics of alternative fuel facilities. Integration concepts include heat recovery, as well as several uses of byproduct nitrogen to enhance gas turbine operation or power production. Start-up, control and operational aspects are presented to complete the review of integrated designs.Copyright © 1998 by ASME