scholarly journals Industrial Gas Turbine Uprates: Tips, Tricks and Traps

Author(s):  
T. L. Ragland

After industrial gas turbines have been in production for some amount of time, there is often an opportunity to improve or “uprate” the engine’s output power or cycle efficiency or both. In most cases, the manufacturer would like to provide these uprates without compromising the proven reliability and durability of the product. Further, the manufacturer would like the development of this “Uprate” to be low cost, low risk and result in an improvement in “customer value” over that of the original design. This paper describes several options available for enhancing the performance of an existing industrial gas turbine engine and discusses the implications for each option. Advantages and disadvantages of each option are given along with considerations that should be taken into account in selecting one option over another. Specific options discussed include dimensional scaling, improving component efficiencies, increasing massflow, compressor zero staging, increasing firing temperature (thermal uprate), adding a recuperator, increasing cycle pressure ratio, and converting to a single shaft design. The implications on output power, cycle efficiency, off-design performance engine life or time between overhaul (TBO), engine cost, development time and cost, auxiliary requirements and product support issues are discussed. Several examples are provided where these options have been successfully implemented in industrial gas turbine engines.

1998 ◽  
Vol 120 (4) ◽  
pp. 727-734 ◽  
Author(s):  
T. L. Ragland

After industrial gas turbines have been in production for some amount of time, there is often an opportunity to improve or uprate the engine’s output power, cycle efficiency, or both. Typically, the manufacturer would like to provide these uprates without compromising the proven reliability and durability of the product. Further, the manufacturer would like the development of this uprate to be low cost, low risk, and result in an improvement in customer value over that of the original design. This Paper describes several options available for enhancing the performance of an existing industrial gas turbine engine, and discusses the implications for each option. Advantages and disadvantages of each option are given along with considerations that should be taken into account in selecting one option over another. Specific options discussed include dimensional scaling, improving component efficiencies, increasing massflow compressor zero staging, increasing firing temperature (thermal uprate), adding a recuperator, increasing cycle pressure ratio, and converting to a single shaft design. The implications on output power, cycle efficiency, off-design performance engine life or time between overhaul (TBO), engine cost, development time and cost, auxiliary requirements, and product support issues are discussed. Several examples are provided where these options have been successfully implemented in industrial gas turbine engines.


1983 ◽  
Vol 105 (3) ◽  
pp. 417-421 ◽  
Author(s):  
B. Becker ◽  
M. Kwasniewski ◽  
O. von Schwerdtner

With increasing mass flow and constant rotational speed of the single shaft gas turbine, the diameters and tip speeds of compressor and turbine blading have to be enlarged. A significant further increase in mass flow can be achieved with transonic compressor stages, as they have been in service in aero gas turbines for many years. For industrial applications, weight and stage pressure ratio are not nearly as important as efficiency. Therefore, different design criteria had to be applied, which led to a moderate front stage pressure ratio of 1.5 with a rotor tip inlet Mach number of 1.37 and a high solidity blading. In order to simulate the first three stages of a 200-MW gas turbine, a test compressor scaled by 1:5.4 was built and tested. These measurements confirmed the aerodynamic performance in the design point very well. The compressor map showed a satisfactory part speed behavior. These results prove that the single-shaft industrial gas turbine still has a high development potential with respect to power increase. Additionally, with the higher pressure ratio, the cycle efficiency will be improved considerably.


Author(s):  
Satoshi Hada ◽  
Masanori Yuri ◽  
Junichiro Masada ◽  
Eisaku Ito ◽  
Keizo Tsukagoshi

MHI recently developed a 1600°C class J-type gas turbine, utilizing some of the technologies developed in the National Project to promote the development of component technology for the next generation 1700°C class gas turbine. This new frame is expected to achieve higher combined cycle efficiency and will contribute to reduce CO2 emissions. The target combined cycle efficiency of the J type gas turbine will be above 61.5% (gross, ISO standard condition, LHV) and the 1on1 combined cycle output will reach 460MW for 60Hz engine and 670MW for 50Hz engine. This new engine incorporates: 1) A high pressure ratio compressor based on the advanced M501H compressor, which was verified during the M501H development in 1999 and 2001. 2) Steam cooled combustor, which has accumulated extensive experience in the MHI G engine (> 1,356,000 actual operating hours). 3) State-of-art turbine designs developed through the 1700°C gas turbine component technology development program in Japanese National Project for high temperature components. This paper discusses the technical features and the updated status of the J-type gas turbine, especially the operating condition of the J-type gas turbine in the MHI demonstration plant, T-Point. The trial operation of the first M501J gas turbine was started at T-point in February 2011 on schedule, and major milestones of the trial operation have been met. After the trial operation, the first commercial operation has taken place as scheduled under a predominantly Daily-Start-and-Stop (DSS) mode. Afterward, MHI performed the major inspection in October 2011 in order to check the mechanical condition, and confirmed that the hot parts and other parts were in sound condition.


Author(s):  
Richard A. Proeschel

Microturbines are becoming increasingly important in the distributed power generation market. These machines are typically low pressure ratio gas turbines that require a recuperator to achieve the high, 30% or more, efficiency needed to compete in this market. However, the additional efficiency gained by a recuperator can easily be offset by its high initial cost. In response to this challenge, Proe Power Systems has developed, and has a U.S. patent pending on, the Proe 90™ gas turbine recuperator. The principal feature of the Proe 90™ recuperator is that it allows a high performance (high temperature, high effectiveness, low pressure drop) gas turbine recuperator to be manufactured by simply welding, brazing, or otherwise joining standard commercial tubing without the need for special tooling or manufacturing processes. The objective in developing the Proe 90™ recuperator was to provide a recuperator for gas turbine and related applications that can attain a minimum of 90% effectiveness with reasonable size and minimal cost. It meets those objectives by: having linear, counterflow, annular flow paths that avoid any thermal “short circuits”; by having sufficient margin to accommodate potential exhaust gas fouling of the low pressure flow passages; by having all surfaces either curved or stayed by flow tubes so that they can be made from commercially available tube and sheet stock while maintaining high margins of strength and creep resistance; and by avoiding thermal gradient stresses by having all non-isothermal portions of the recuperator able to freely expand and contract. The simple manufacturing process, design modeling techniques and predicted performance of the Proe 90™ recuperator are presented. Effects of tube length, diameter, and numbers of tubes on effectiveness and pressure losses are quantified. Additional parametric data show the effectiveness losses caused by axial conduction, flow misdistribution, manufacturing tolerances, and insulation losses. The Proe 90™ recuperator is ideally suited for microturbine distributed power applications in the 20–50 kW range. With properly sized tubes, the flow regime is laminar and results in a very small pressure loss while still producing very high heat exchanger effectiveness in a low cost, compact package.


Entropy ◽  
2019 ◽  
Vol 21 (3) ◽  
pp. 265 ◽  
Author(s):  
Lei Qi ◽  
Zhitao Wang ◽  
Ningbo Zhao ◽  
Yongqiang Dai ◽  
Hongtao Zheng ◽  
...  

To further improve the cycle performance of gas turbines, a gas turbine cycle model based on interstage bleeding rotating detonation combustion was established using methane as fuel. Combined with a series of two-dimensional numerical simulations of a rotating detonation combustor (RDC) and calculations of cycle parameters, the pressure gain characteristics and cycle performance were investigated at different compressor pressure ratios in the study. The results showed that pressure gain characteristic of interstage bleeding RDC contributed to an obvious performance improvement in the rotating detonation gas turbine cycle compared with the conventional gas turbine cycle. The decrease of compressor pressure ratio had a positive influence on the performance improvement in the rotating detonation gas turbine cycle. With the decrease of compressor pressure ratio, the pressurization ratio of the RDC increased and finally made the power generation and cycle efficiency enhancement rates display uptrends. Under the calculated conditions, the pressurization ratios of RDC were all higher than 1.77, the decreases of turbine inlet total temperature were all more than 19 K, the power generation enhancements were all beyond 400 kW and the cycle efficiency enhancement rates were all greater than 6.72%.


Author(s):  
D. M. S. Lightbody

The paper covers the basic thermodynamics of the combined cycle concept and illustrates that energy conservation is possible by coupling the Joule and Rankine cycles. It discusses the optimisation of steam conditions and outlines the concept of the unfired combined cycle. “Carnot efficiency” and “pinch points” are shown to be important as is the concept of “specific work” as it relates to the gas turbine in arriving at the best overall cycle efficiencies. The importance of the efficiency characteristic of the steam turbine is emphasised and it is shown that this characteristic will determine the overall cycle efficiency. It is suggested that steam turbine manufacturers should design and develop steam turbines to match the advanced gas turbines available to-day and so enchance the overall efficiency which can presently be obtained from to-day’s combined cycle. Market forces will tend to bring this about as evidenced by the growing interest being shown in this concept both in the UK and Europe.


Author(s):  
Christian Vandervort ◽  
David Leach ◽  
David Walker ◽  
Jerry Sasser

Abstract The power generation industry is facing unprecedented challenges. High fuel costs and increased penetration of renewable power have resulted in greater demand for high efficiency and operational flexibility. Imperatives to reduce carbon footprint place an even higher premium on efficiency. Power producers are seeking highly efficient, reliable, and operationally flexible solutions that provide long-term profitability in a volatile environment. New generation must also be cost-effective to ensure affordability for both domestic and industrial consumers. Gas turbine combined cycle power plants meet these requirements by providing reliable, dispatchable generation with a low cost of electricity, reduced environmental impact, and broad operational flexibility. Start times for large, industrial gas turbine combined cycles are less than 30 minutes from turning gear to full load, with ramp rates from 60 to 88 MW/minute. GE introduced the 7/9HA industrial gas turbine product portfolio in 2014 in response to these demands. These air-cooled, H-class gas turbines (7/9HA) are engineered to achieve greater than 63% net combined cycle efficiency while delivering operational flexibility through deep, emission-compliant turndown and high ramp rates. The largest of these gas turbines, the 9HA.02, is designed to exceed 64% combined cycle efficiency (net, ISO) in a 1×1, single-shaft (SS) configuration. As of December 2018, a total of 32 7/9HA power plants have achieved COD (Commercial Operation Date) while accumulating over 220,000 hours of operation. These plants operate across a variety of demand profiles including base load and load following (intermediate) service. Fleet leaders for both the 7HA and 9HA have exceeded 12,000 hours of operation, with multiple units over 8,000 hours. This paper will address four topics relating to the HA platform: 1) gas turbine product technology, 2) gas turbine validation, 3) integrated power plant commissioning and operating experience, and 4) lessons learned and fleet reliability.


Author(s):  
Meherwan P. Boyce

The performance analysis of the new generation of Gas Turbines in combined cycle operation is complex and presents new problems, which have to be addressed. The new units operate at very high turbine firing temperatures. Thus variation in this firing temperature significantly affects the performance and life of the components in the hot section of the turbine. The compressor pressure ratio is high which leads to a very narrow operation margin, thus making the turbine very susceptible to compressor fouling. The turbines are also very sensitive to backpressure exerted on them by the heat recovery steam generators. The pressure drop through the air filter also results in major deterioration of the performance of the turbine. The performance of the combined cycle is also dependent on the steam turbine performance. The steam turbine is dependent on the pressure, temperature, and flow generated in the heat recovery steam generator, which in turn is dependent on the turbine firing temperature, and the air mass flow through the gas turbine. It is obvious that the entire system is very intertwined and that deterioration of one component will lead to off-design operation of other components, which in most cases leads to overall drop in cycle efficiency. Thus, determining component performance and efficiency is the key to determining overall cycle efficiency. Thermodynamic modeling of the plant with individual component analysis is not only extremely important in optimizing the overall performance of the plant but in also determining life cycle considerations.


Author(s):  
Thomas L. Ragland

With the increasing need for more efficient industrial gas turbine engines, the recuperated engine cycle is being considered as a means of meeting these needs. This paper discusses a recuperated cycle design that is optimized to take full advantage of the recuperator but at the same time accommodate the real world market constraints of reliability, durability and cost. Current simple cycle industrial engines are evolving to very high pressure ratios and high firing temperatures in order to reach cycle efficiencies in the 37% to 39% range. Some simple cycle industrial gas turbines with lower cycle pressure ratios and firing temperatures have been modified so a recuperated option can be added. Although the addition of a recuperator to these engines does improve cycle efficiency, levels of only the 33% to 35% range are reached. This is mainly due to the fact that the resulting cycles are not optimized for a recuperator. An engine cycle that is optimized around a recuperator could obtain cycle efficiencies in the 43% to 45% range. Fortunately, this cycle optimizes at low pressure ratios and modest firing temperatures which results in lower cost components which tend to offset the additional cost of the recuperator.


Author(s):  
John L. Mason ◽  
Anthony Pietsch ◽  
Theodore R. Wilson ◽  
Allen D. Harper

A novel closed-cycle gas turbine power system is now under development by the GWF Power Systems Company for cogeneration applications. Nominally the system produces 5 megawatts (MW) of electric power and 80,000 lb/hr (36,287 kg/hr) of 1000 psig (6895 kPa) steam. The heat source is an atmospheric fluidized bed combustor (AFBC) capable of using low-cost solid fuels while meeting applicable emission standards. A simple, low-pressure ratio, single spool, turbomachine is utilized. This paper describes the system and related performance, as well as the development and test efforts now being conducted. The initial commercial application of the system will be for Enhanced Oil Recovery (EOR) of the heavy crudes produced in California.


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