Partial Regenerative Steam Injected Gas Turbine

Author(s):  
Shigekazu Uji

Steam injection has been employed in gas turbines for over twenty-five years for power increase (more than 50% on some gas turbines) and efficiency improvements (more than 20%). For further improvement of efficiency on steam injected gas turbine, Partial Regenerative Steam Injected Gas Turbine was studied. Cycle analysis was carried out for the evaluation of efficiency among three systems, Steam Injected Gas Turbine, Regenerative Steam Injected Gas Turbine and Partial Regenerative Steam Injected Gas Turbine. Results of the analysis show that Partial Regenerative Steam Injected Gas Turbine can realize higher efficiency than other two systems. In addition to the cycle analysis, the effect of applying the concept of Partial Regenerative Steam Injected Gas Turbine to the actual engine Allison gas turbine model 501-KH was evaluated. And the effect of integrating compressor inter-cooling process in Partial Regenerative Steam Injected Gas Turbine was also evaluated.

Author(s):  
C. Kalathakis ◽  
N. Aretakis ◽  
I. Roumeliotis ◽  
A. Alexiou ◽  
K. Mathioudakis

The concept of solar steam production for injection in a gas turbine combustion chamber is studied for both nominal and part load engine operation. First, a 5MW single shaft engine is considered which is then retrofitted for solar steam injection using either a tower receiver or a parabolic troughs scheme. Next, solar thermal power is used to augment steam production of an already steam injected single shaft engine without any modification of the existing HRSG by placing the solar receiver/evaporator in parallel with the conventional one. For the case examined in this paper, solar steam injection results to an increase of annual power production (∼15%) and annual fuel efficiency (∼6%) compared to the fuel-only engine. It is also shown that the tower receiver scheme has a more stable behavior throughout the year compared to the troughs scheme that has better performance at summer than at winter. In the case of doubling the steam-to-air ratio of an already steam injected gas turbine through the use of a solar evaporator, annual power production and fuel efficiency increase by 5% and 2% respectively.


Author(s):  
Xueyou Wen ◽  
Jiguo Zou ◽  
Zheng Fu ◽  
Shikang Yu ◽  
Lingbo Li

Steam-injected gas turbines have a multitude of advantages, but they suffer from the inability to recover precious demineralized water. The present paper describes the test conditions and results of steam injection along with an attempt to achieve water recovery, which were obtained through a series of tests conducted on a S1A-02 small-sized industrial gas turbine. A water recovery device incorporating a compact finned spiral plate cooling condenser equipped with filter screens has been designed for the said gas turbine and a 100% water recovery (based on the design point) was attained.


1990 ◽  
Vol 112 (2) ◽  
pp. 157-163 ◽  
Author(s):  
E. D. Larson ◽  
R. H. Williams

Steam injection for power and efficiency augmentation in aeroderivative gas turbines is now commercially established for natural gas-fired cogeneration. Steam-injected gas turbines fired with coal and biomass are being developed. In terms of efficiency, capital cost, and commercial viability, the most promising way to fuel steam-injected gas turbines with biomass is via the biomass-integrated gasifier/steam-injected gas turbine (BIG/STIG). The R&D effort required to commercialize the BIG/STIG is modest because it can build on extensive previous coal-integrated gasifier/gas turbine development efforts. An economic analysis of BIG/STIG cogeneration is presented here for cane sugar factories, where sugar cane residues would be the fuel. A BIG/STIG investment would be attractive for sugar producers, who could sell large quantities of electricity, or for the local electric utility, as a low-cost generating option. Worldwide, the cane sugar industry could support some 50,000 MW of BIG/STIG capacity, and there are many potential applications in the forest products and other biomass-based industries.


Author(s):  
Carlo M. Bartolini ◽  
Danilo Salvi

The steam generated through the use of waste heat recovered from a steam injection gas turbine generally exceeds the maximum mass of steam which can be injected into steam injection gas turbine. The ratio between the steam and air flowing into the engine is not more than 10–15%, as an increase in the pressure ratio can cause the compressor to stall. Naturally, the surplus steam can be utilized for a variety of alternative applications. During the warmer months, the ambient temperature increases and results in reduced thermal efficiency and electrical capacity. An inlet air cooling system for the compressor on a steam injection gas turbine would increase the rating and efficiency of power plants which use this type of equipment. In order to improve the performance of steam injection gas turbines, the authors investigated the option of cooling the intake air to the compressor by harnessing the thermal energy not used to produce the maximum quantity of steam that can be injected into the engine. This alternative use of waste energy makes it possible to reach maximum efficiency in terms of waste recovery. This study examined absorption refrigeration technology, which is one of the various systems adopted to increase efficiency and power rating. The system itself consists of a steam injection gas turbine and a heat recovery and absorption unit, while a computer model was utilized to evaluate the off design performance of the system. The input data required for the model were the following: an operating point, the turbine and compressor curves, the heat recovery and chiller specifications. The performance of an Allison 501 KH steam injection gas plant was analyzed by taking into consideration representative ambient temperature and humidity ranges, the optimal location of the chiller in light of all the factors involved, and which of three possible air cooling systems was the most economically suitable. In order to verify the technical feasibility of the hypothetical model, an economic study was performed on the costs for upgrading the existing steam injection gas cogeneration unit. The results indicate that the estimated pay back period for the project would be four years. In light of these findings, there are clear technical advantages to using gas turbine cogeneration with absorption air cooling in terms of investment.


Author(s):  
Mohsen Ghazikhani ◽  
Nima Manshoori ◽  
Davood Tafazoli

An industrial gas turbine has the characteristic that turbine output decreases on hot summer days when electricity demand peaks. For GE-F5 gas turbines of Mashad Power Plant when ambient temperature increases 1° C, compressor outlet temperature increases 1.13° C and turbine exhaust temperature increases 2.5° C. Also air mass flow rate decreases about 0.6 kg/sec when ambient temperature increases 1° C, so it is revealed that variations are more due to decreasing in the efficiency of compressor and less due to reduction in mass flow rate of air as ambient temperature increases in constant power output. The cycle efficiency of these GE-F5 gas turbines reduces 3 percent with increasing 50° C of ambient temperature, also the fuel consumption increases as ambient temperature increases for constant turbine work. These are also because of reducing in the compressor efficiency in high temperature ambient. Steam injection in gas turbines is a way to prevent a loss in performance of gas turbines caused by high ambient temperature and has been used for many years. VODOLEY system is a steam injection system, which is known as a self-sufficient one in steam production. The amount of water vapor in combustion products will become regenerated in a contact condenser and after passing through a heat recovery boiler is injected in the transition piece after combustion chamber. In this paper the influence of steam injection in Mashad Power Plant GE-F5 gas turbine parameters, applying VODOLEY system, is being observed. Results show that in this turbine, the turbine inlet temperature (T3) decreases in a range of 5 percent to 11 percent depending on ambient temperature, so the operating parameters in a gas turbine cycle equipped with VODOLEY system in 40° C of ambient temperature is the same as simple gas turbine cycle in 10° C of ambient temperature. Results show that the thermal efficiency increases up to 10 percent, but Back-Work ratio increases in a range of 15 percent to 30 percent. Also results show that although VODOLEY system has water treatment cost but by using this system the running cost will reduce up to 27 percent.


Author(s):  
Abdallah Bouam ◽  
Slimane Aissani ◽  
Rabah Kadi

The gas turbines are generally used for large scale power generation. The basic gas turbine cycle has low thermal efficiency, which decreases in the hard climatic conditions of operation, so the cycles with thermodynamic improvement is found to be necessary. Among several methods shown their success in increasing the performances, the steam injected gas turbine cycle (STIG) consists of introducing a high amount of steam at various points in the cycle. The main purpose of the present work is to improve the principal characteristics of gas turbine used under hard condition of temperature in Algerian Sahara by injecting steam in the combustion chamber. The suggested method has been studied and compared to a simple cycle. Efficiency, however, is held constant when the ambient temperature increases from ISO conditions to 50°C. Computer program has been developed for various gas turbine processes including the effects of ambient temperature, pressure ratio, injection parameters, standard temperature, and combustion chamber temperature with and without steam injection. Data from the performance testing of an industrial gas turbine, computer model, and theoretical study are used to check the validity of the proposed model. The comparison of the predicted results to the test data is in good agreement. Starting from the advantages, we recommend the use of this method in the industry of hydrocarbons. This study can be contributed for experimental tests.


Author(s):  
Matthias Utschick ◽  
Thomas Sattelmayer

Flashback and self-ignition in the premixing zone of typical gas turbine swirl combustors in lean premixed operation are immanent risks and can lead to damage and failure of components. Thus, steady combustion in the premixing zone must be avoided under all circumstances. This study experimentally investigates the flame holding propensity of fuel injectors in the swirler of a gas turbine model combustor with premixing of H2-NG-air-mixtures under atmospheric pressure and proposes a model to predict the limit for safe operation. The A2EV swirler concept exhibits a hollow, thick walled conical structure with four tangential slots. Four fuel injector geometries were tested. One of them injects the fuel orthogonal to the air flow in the slots (jet-in-crossflow-injector, JICI). Three injector types introduce the fuel almost isokinetic to the air flow at the trailing edge of the swirler slots (trailing edge injector, TEI). A cylindrical duct and a window in the swirler made of quartz glass allow the application of optical diagnostics (OH* chemiluminescence and Planar Laser Induced Fluorescence of the OH radical (OH-PLIF)) inside the swirler. The fuel-air-mixture was ignited with a focused single laser pulse during steady operation. The position of ignition was located inside the swirler in proximity to a fuel injection hole. If the flame was washed out of the premixing zone not later than four seconds after the ignition the operation point was defined as safe. Operation points were investigated at three air mass flows, three air ratios, two air preheat temperatures (573 K, 673 K) and 40 to 100 percent per volume hydrogen in the fuel composed of hydrogen and natural gas. The determined safety limit for atmospheric pressure yields a similarity rule based on a critical Damköhler number. Application of the proposed rule at conditions typical for gas turbines leads to these safety limits for the A2EV burner: With the TEIs the swirler can safely operate with up to 80 percent per volume hydrogen content in the fuel at an air ratio of two. With the JIC injector safe operation at stoichiometric conditions and 95 percent per volume hydrogen is possible.


Author(s):  
Dah Yu Cheng ◽  
Albert L. C. Nelson

It has always been thought by the gas turbine industry that steam injection will shorten the effective life of certain gas turbine parts. Recently it was shown that a number of steam injected Cheng Cycle Rolls-Royce Allison 501KH gas turbines, accumulated more than 2.5 million logged hours of operation and with a prolonged parts life. The “hot parts” of a Rolls-Royce Allison 501KH gas turbine engine that are of concern, are the first stage nozzle, the first stage blade, and the second stage nozzle. These parts are all air cooled through the first stages internal passages. (The second stage blades and on down are not internally cooled.) The concern raised in many gas turbine institutions is that the metal temperatures of these hot parts, due to the heat conductivity properties of injected steam, will make them deteriorate faster. An experiment was completed using a steam injected Cheng Cycle, on an Allison 501KH gas turbine engine. In the experiment, a substantial number of thermocouples were attached to the surfaces of the turbines hot parts. This engine had a steam injection rate of up to 18% airflow. The experimental results showed that if steam could be properly mixed with the cooling air before the air enters into the cooling passages of the hot parts, the metal temperatures did not increase. During the operation of the engines, it was recorded that the hot parts lifetime increased from 25,000 hours before the hot parts section had to be overhauled, to 42,000 hours (on average) before they needed to be overhauled. This paper will report the measurement installation in detail. The results before and after steam injection in the hot parts sections of the Rolls-Royce Allison 501KH engine will also be discussed.


Author(s):  
Robert E. Dundas ◽  
Daniel A. Sullivan ◽  
Frank Abegg

The concept of performance monitoring for prevention of certain serious failures in gas turbines is described. The use of compressor mapping as the key to avoiding surge is developed, and an example is presented showing how the compressor in a steam-injected gas turbine can be much closer to surge in one of two nearly-identical operating points on a steam-injection control envelope than the compressor in the other. The technique of monitoring blade-path temperature spread in the exhaust of a gas turbine is then described, and examples of its value in preventing combustor burnout and turbine blade failures in high-frequency fatigue are given. Next, a concept of diagnosing internal deterioration by recognizing patterns of deviation of operating parameters from baseline data is described, and illustrated for a single-shaft generator-drive gas turbine. Finally, the use of a modern computer-controlled data acquisition system to perform the above monitoring functions in real time is demonstrated.


2020 ◽  
Author(s):  
Chang Cho

The potential execution of optimized gas-steam combined cycles built around the latest generation gas turbine motors is analyzed, by implies of energy/exergy equalizations. The options here considered are the warm gas turbine and the H-series with closed-loop steam edge cooling.Recreations of execution were run employing a well-tested Modular Code created at the Office of Vitality Designing of Florence and subsequently improved to incorporate the calculation of exergy pulverization of all sorts (warm transfer, friction, blending, and chemical irreversibilities). The edge cooling process is analyzed in detail because it is recognized to be of capital significance for execution optimization. The distributions of the relative exergy devastation for the two solutions both competent of achieving energy/exergy efficiencies within the extend of 60 percent are compared and the potential for advancement is examined<br>


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