Exergy Analysis of Combined Cycles: Part 2—Analysis and Optimization of Two-Pressure Steam Bottoming Cycles

1987 ◽  
Vol 109 (2) ◽  
pp. 237-243 ◽  
Author(s):  
W. W. Chin ◽  
M. A. El-Masri

Results of a study for selecting the optimum parameters of a dual-pressure bottoming cycle as a function of the gas turbine exhaust temperature are presented. Realistic constraints reflecting current technological practice are assumed. Exergy analysis is applied to quantify all loss sources in each cycle. Compared to a single pressure at typical exhaust gas temperatures the optimized dual-pressure configuration is found to increase steam cycle work output on the order of 3 percent, principally through the reduction of the heat transfer irreversibility from about 15 to 8 percent of the exhaust gas energy. Measures to further reduce the heat transfer irreversibility such as three-pressure systems or use of multicomponent mixtures can therefore only result in modest additional gains. The results for the efficiency of optimized dual-pressure bottoming cycles are correlated against turbine exit temperature by simple polynomial fits. Sensitivity of the results to variations in the constraint envelope are presented.

Author(s):  
W. W. Chin ◽  
M. A. El-Masri

Results of a study for selecting the optimum parameters of a dual-pressure bottoming cycle as a function of the gas turbine exhaust temperature are presented. Realistic constraints reflecting current technological practice are assumed. Exergy analysis is applied to quantify all loss sources in each cycle. Compared to a single pressure at typical exhaust gas temperatures the optimized dual-pressure configuration is found to increase steam cycle work output on the order of 3%, principally through the reduction of the heat transfer irreversibility from about 15% to 8% of the exhaust gas energy. Measures to further reduce the heat transfer irreversibility such as three-pressure systems or use of multi-component mixtures can therefore only result in modest additional gains. The results for the efficiency of optimized dual pressure bottoming cycles are correlated against turbine exit temperature by simple polynomial fits. Sensitivity of the results to variations in the constraint envelope are presented.


Author(s):  
Franz J. Dutz ◽  
Sven Boje ◽  
Ulrich Orth ◽  
Alexander W. Koch ◽  
Johannes Roths

In this paper, the deployment of a newly developed, multipoint, fiber-optic temperature-sensor system for temperature distribution measurements in a 6 MW gas turbine is demonstrated. The optical sensor fiber was integrated in a stainless steel protection cable with a 1.6 mm outside diameter. It included six measurement points, distributed over a length of 110 mm. The sensor cable was mounted in a temperature probe and was positioned radially in the exhaust-gas diffusor of the turbine. With this temperature probe, the radial temperature profiles in the exhaust-gas diffusor were measured with high spatial and temporal resolution. During a test run of the turbine, characteristic temperature gradients were observed when the machine operated at different loads.


2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Zhi-tao Wang ◽  
Ning-bo Zhao ◽  
Wei-ying Wang ◽  
Rui Tang ◽  
Shu-ying Li

As an important gas path performance parameter of gas turbine, exhaust gas temperature (EGT) can represent the thermal health condition of gas turbine. In order to monitor and diagnose the EGT effectively, a fusion approach based on fuzzy C-means (FCM) clustering algorithm and support vector machine (SVM) classification model is proposed in this paper. Considering the distribution characteristics of gas turbine EGT, FCM clustering algorithm is used to realize clustering analysis and obtain the state pattern, on the basis of which the preclassification of EGT is completed. Then, SVM multiclassification model is designed to carry out the state pattern recognition and fault diagnosis. As an example, the historical monitoring data of EGT from an industrial gas turbine is analyzed and used to verify the performance of the fusion fault diagnosis approach presented in this paper. The results show that this approach can make full use of the unsupervised feature extraction ability of FCM clustering algorithm and the sample classification generalization properties of SVM multiclassification model, which offers an effective way to realize the online condition recognition and fault diagnosis of gas turbine EGT.


Author(s):  
Hiwa Khaledi ◽  
Kazem Sarabchi

Combined cycles, at present, have a prominent role in the power generation and advanced combined cycles efficiencies have now reached to 60 percent. Examination of thermodynamic behavior of these cycles is still carried out to determine optimum configuration and optimum design conditions for any cycle arrangement. Actually the performance parameters of these cycles are under the influence of various parameters and therefore the recognition of the optimum conditions is quiet complicated. In this research an extensive thermodynamic model was developed for analyzing major parameters variations on gas turbine performance and different configurations of advanced steam cycles: dual and triple pressure cycles with and without reheating in steam turbine sections. In this model it is attempted to consider all factors that affect on actual behavior of these cycles such as blade cooling (air cooling) in gas turbine and different formulations for Heat Recovery Steam Generator (HRSG) performance calculation. Results show good agreement with manufactures data. In the case of gas turbine cycle, location of coolant extraction has large influence on cycle performance. For extraction from compressor end, improving blade cooling technology is suitable than increasing TIT. For mid stage extraction, improving blade cooling technology and TIT has similar effects on efficiency, while power is more sensitive to TIT. Coolant air precooling has large positive effect in high TIT and medium blade cooling technology, but always it increases power. Turbine exhaust temperature has large influence on optimum layout and configuration of HRSG, while for low exhaust temperatures increasing number of pressure levels increase power and heat recovery greatly, for high exhaust temperatures this leads lower enhancement in power and recovery. Second law efficiency of HRSG is proportional to power production in steam cycle. It decreases with increasing gas turbine exhaust temperature.


2014 ◽  
Vol 1078 ◽  
pp. 280-285 ◽  
Author(s):  
Tao Sun ◽  
Bo Wan ◽  
Chang Jiang Sun ◽  
Zheng Wei Ma

With the continuous development of infrared-guided weapons, the survival of ship at sea faces increasingly challenges especially high-risk waters. The ship gas turbine exhaust ejector is the core component parts, charged with the task of reducing or even eliminating the infrared radiation signal of ship gas turbine exhaust systems. In the designing of exhaust ejector, structure forms of nozzle have a big influence on its ejector effect. Making a rational design of nozzle, which working in a narrow space, to reduce the exhaust temperature effectively while minimizing the impact of flow of gas turbine body has always been a focus and difficulty. In this article, a multistage ejector is designed by adding a second-stage ejector section based on an independent design of single-stage ejector.


2002 ◽  
Vol 124 (3) ◽  
pp. 496-502 ◽  
Author(s):  
B. E. Lee ◽  
S. B. Kwon ◽  
C. S. Lee

Computational and experimental studies are performed to investigate the effect of swirl flow of gas turbine exhaust gas (GTEG) in an inlet duct of a heat recovery steam generator (HRSG). A supplemental-fired HRSG is chosen as the model studied because the uniformity of the GTEG at the inlet plane of the duct burner is essential in such applications. Both velocity and oxygen distributions are investigated at the inlet plane of the duct burner installed in the middle of the HRSG transition duct. Two important parameters, the swirl angle of GTEG and the momentum ratio of additional air to GTEG, are chosen for the investigation of mixing between the two streams. It has been found that a flow correction device (FCD) is essential to provide a uniform gas flow distribution at the inlet plane of the duct burner.


1979 ◽  
Author(s):  
Y. Hishinuma ◽  
F. Nakajima ◽  
H. Akimoto ◽  
Y. Uchiyama ◽  
S. Azuhata ◽  
...  

For the removal of NOx in a gas turbine exhaust gas, the reduction of NOx with NH3 and H2O2 was studied. It was found that the addition of H2O2 very effectively lowers the reduction temperature of NO with NH3 and that more than 90 percent NOx reduction could be attained at 550 C in the absence of O2. However, the NOx reduction rate decreased with increases in the concentration of O2, and NOx reduction was about 40 to 60 percent under gas turbine exhaust gas condition (15 percent O2). In order to attain a high rate of reduction of NOx, a combined reduction process, which consisted of homogeneous gas phase and the catalytic heterogeneous reactions, was also developed. The efficiency of the new process was proved in a pilot plant using half a size model of a 25-MW gas turbine combustor.


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