scholarly journals Application of Water Cooling for Improved Gas Turbine Fuel Flexibility and Availability

Author(s):  
R. S. Rose ◽  
A. Caruvana ◽  
H. Von E. Doering ◽  
D. P. Smith ◽  
A. Cohn

Near term application of water cooling to stage 1 nozzles on present day gas turbines results in significant improvements in fuel flexibility and performance. Design and performance calculations for application of a water-cooled stage 1 nozzle are compared to an air-cooled stage 1 nozzle in a heavy duty gas turbine. The results of ash deposition tests of both air-cooled and water-cooled nozzles using simulated residual fuel are presented for firing temperatures of 1850°F and 2050°F. This work was jointly sponsored by the Electric Power Research Institute and General Electric under the Advanced Cooling, Full-Scale Engine Demonstration Program.

Author(s):  
R. S. Rose ◽  
A. Caruvana ◽  
A. Cohn ◽  
H. Von Doering

The results of ash deposition tests with simulated residual oil are presented. Both air-cooled and water-cooled nozzles were tested over a range of firing temperature, fuel contaminant levels, and metal surface temperatures. Extensive ash cleaning tests were also completed under full, steady-state operating conditions. Various online ash removal techniques were tested including small nutshells, large nutshells, coke particles, and water droplets. The results of these tests were applied to a General Electric gas turbine to predict actual field operation at turbine inlet temperatures up to 2300°F (1260°C). Use of on-line ash removal and optimum water washing intervals are shown to significantly improve the economics of gas turbine operation on heavy fuels. The improvements in heavy fuel operation were larger with a water-cooled stage 1 nozzle than with an air-cooled nozzle. This work was jointly sponsored by the Electric Power Research Institute and General Electric under the Advanced Cooling, Full-Scale Engine Demonstration Program.


Author(s):  
S. Ezhil Arasan ◽  
Vijayan. M

In this paper, the parameters of Rowen’s model for heavy duty gas turbines in dynamic studies are estimated by use of available operational and performance data. The transfer function model of heavy duty gas turbine is required for the analysis and development of optimal controllers. The speedtronic controller derived from Rowen’s model has three controller namely, speed, acceleration and temperature. The model with all these controllers is developed with MATLAB/Simulink to study their response and arrive at the simplified model. The speed controller may have isochronous or drooping governor characteristics. The choice of governor characteristics for the simplified model is made from the response of the system simulated for an unit step load disturbance. The equations are to be validated with the response of the system simulated using MATLAB/Simulink.


1980 ◽  
Author(s):  
M. W. Horner ◽  
A. Caruvana ◽  
A. Cohn ◽  
D. P. Smith

A joint General Electric and Electric Power Research program is nearing completion after six years of water-cooled turbine technology development. The first two years were devoted to preliminary combined gas and steam turbine cycle studies and preliminary gas turbine combustor and turbine hot section design studies. Beginning in 1976, the major emphasis has been on resolving areas of critical technology toward the application of water cooling to the heavy duty commercial gas turbine. Earlier papers, ASME 78-GT-72 and 79-GT-72, presented preliminary results for development tasks which investigated phenomena associated with application of water cooling to turbine hot section nozzles, buckets and flowpath components for operation at increased turbine firing temperature. This paper presents results obtained from mid-1978 through 1979, and deals primarily with near term application of water cooling technology to the commercial gas turbine operating on heavy residual oil or coal derived liquid fuels. Water cooling in the near term offers the promise of significant reduction of both hot corrosion and ash deposition at the turbine first-stage nozzle.


Author(s):  
Arthur Cohn

The EPRI projects for the development of water-cooled gas turbine power plants have been completed, while the DOE project on this subject (HTTT) is completing Phase II with little likelihood for further funding. This paper presents the prospects of water-cooled power plants as currently evaluated at EPRI. It is concluded that: water cooling designs for the stationary components are commercially ready, but technology development work is still required for the rotating components; water cooled turbines can have much lower ash deposition and corrosion rates than air cooled ones when firing on ash-containing fuels; water cooling provides considerable increase in specific power, but there is little advantage, if any, in efficiency compared to air cooling. The water-cooled gas turbine has its main attractiveness for operation with ash-containing fuels at base load. However, since this type of operation is not currently foreseen for American utility practice, the near-term continued development of the water-cooled gas turbine power plant is not expected to proceed.


Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3521 ◽  
Author(s):  
Panagiotis Stathopoulos

Conventional gas turbines are approaching their efficiency limits and performance gains are becoming increasingly difficult to achieve. Pressure Gain Combustion (PGC) has emerged as a very promising technology in this respect, due to the higher thermal efficiency of the respective ideal gas turbine thermodynamic cycles. Up to date, only very simplified models of open cycle gas turbines with pressure gain combustion have been considered. However, the integration of a fundamentally different combustion technology will be inherently connected with additional losses. Entropy generation in the combustion process, combustor inlet pressure loss (a central issue for pressure gain combustors), and the impact of PGC on the secondary air system (especially blade cooling) are all very important parameters that have been neglected. The current work uses the Humphrey cycle in an attempt to address all these issues in order to provide gas turbine component designers with benchmark efficiency values for individual components of gas turbines with PGC. The analysis concludes with some recommendations for the best strategy to integrate turbine expanders with PGC combustors. This is done from a purely thermodynamic point of view, again with the goal to deliver design benchmark values for a more realistic interpretation of the cycle.


Author(s):  
Wolfgang Kappis ◽  
Stefan Florjancic ◽  
Uwe Ruedel

Market requirements for the heavy duty gas turbine power generation business have significantly changed over the last few years. With high gas prices in former times, all users have been mainly focusing on efficiency in addition to overall life cycle costs. Today individual countries see different requirements, which is easily explainable picking three typical trends. In the United States, with the exploitation of shale gas, gas prices are at a very low level. Hence, many gas turbines are used as base load engines, i.e. nearly constant loads for extended times. For these engines reliability is of main importance and efficiency somewhat less. In Japan gas prices are extremely high, and therefore the need for efficiency is significantly higher. Due to the challenge to partly replace nuclear plants, these engines as well are mainly intended for base load operation. In Europe, with the mid and long term carbon reduction strategy, heavy duty gas turbines is mainly used to compensate for intermittent renewable power generation. As a consequence, very high cyclic operation including fast and reliable start-up, very high loading gradients, including frequency response, and extended minimum and maximum operating ranges are required. Additionally, there are other features that are frequently requested. Fuel flexibility is a major demand, reaching from fuels of lower purity, i.e. with higher carbon (C2+), content up to possible combustion of gases generated by electrolysis (H2). Lifecycle optimization, as another important request, relies on new technologies for reconditioning, lifetime monitoring, and improved lifetime prediction methods. Out of Alstom’s recent research and development activities the following items are specifically addressed in this paper. Thermodynamic engine modelling and associated tasks are discussed, as well as the improvement and introduction of new operating concepts. Furthermore extended applications of design methodologies are shown. An additional focus is set ono improve emission behaviour understanding and increased fuel flexibility. Finally, some applications of the new technologies in Alstom products are given, indicating the focus on market requirements and customer care.


Author(s):  
Douglas A. Pennell ◽  
Mirko R. Bothien ◽  
Andrea Ciani ◽  
Victor Granet ◽  
Ghislain Singla ◽  
...  

This paper introduces and presents validation of the Constant Pressure Sequential Combustion system (denoted CPSC), a second generation concept developed for and applied to the new Ansaldo GT36 H-class gas turbine combustors. It has evolved from the well-established sequential burner technology applied to all current GT26 and GT24 gas turbines, and contains all architectural improvements implemented since original inception of this engine frame in 1994, with beneficial effects on the operation turndown, fuel flexibility, on the overall system robustness, and featuring the required aspects to stay competitive in the present day energy market. The applied air and fuel management therefore facilitate emission and dynamics control at both the extremely high and low firing temperature ranges required for existing and future Ansaldo gas turbine engine classes.


Author(s):  
Z. Stanley Stys

Application of the gas turbine in nitric-acid plants appears attractive. Several of these units have been installed recently in this country and performance and operating experience already have been gained. Design, construction, and layout of “package” units for this particular process are described.


Author(s):  
O. R. Schmoch ◽  
B. Deblon

The peripheral speeds of the rotors of large heavy-duty gas turbines have reached levels which place extremely high demands on material strength properties. The particular requirements of gas turbine rotors, as a result of the cycle, operating conditions and the ensuing overall concepts, have led different gas turbine manufacturers to produce special structural designs to resolve these problems. In this connection, a report is given here on a gas turbine rotor consisting of separate discs which are held together by a center bolt and mutually centered by radial serrations in a manner permitting expansion and contraction in response to temperature changges. In particular, the experience gained in the manufacture, operation and servicing are discussed.


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