Acceptance Criteria for Heat Recovery Steam Generators Behind Gas Turbines

Author(s):  
Akber Pasha

The design of a Heat Recovery Steam Generator behind a gas turbine depends upon various input parameters such as gas turbine exhaust flow, exhaust temperature, etc. Most of the input parameters are either measured with tolerances or calculated based on experimental correlations. The design of the heat recovery steam generator itself utilizes various correlations and empirical values. The errors or measurement tolerances in these variables affect the performance of the steam generator. This paper describes the various design parameters, the possible magnitude of errors in these parameters and the overall effect on the steam generator’s performance. By utilizing the information given in this paper, it is possible to develop a performance envelope based on the possible error margins of the input variables. The steam generator performance can be deemed acceptable if it is within this envelope.

Author(s):  
Akber Pasha

In recent years the combined cycle has become a very attractive power plant arrangement because of its high cycle efficiency, short order-to-on-line time and flexibility in the sizing when compared to conventional steam power plants. However, optimization of the cycle and selection of combined cycle equipment has become more complex because the three major components, Gas Turbine, Heat Recovery Steam Generator and Steam Turbine, are often designed and built by different manufacturers. Heat Recovery Steam Generators are classified into two major categories — 1) Natural Circulation and 2) Forced Circulation. Both circulation designs have certain advantages, disadvantages and limitations. This paper analyzes various factors including; availability, start-up, gas turbine exhaust conditions, reliability, space requirements, etc., which are affected by the type of circulation and which in turn affect the design, price and performance of the Heat Recovery Steam Generator. Modern trends around the world are discussed and conclusions are drawn as to the best type of circulation for a Heat Recovery Steam Generator for combined cycle application.


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):  
L. F. Fougere ◽  
H. G. Stewart ◽  
J. Bell

Citizens Utilities Company’s Kauai Electric Division is the electric utility on the Island of Kauai, fourth largest and westernmost as well as northernmost of the Hawaiian Islands. As a result of growing load requirements, additional generating capacity was required that would afford a high level of reliability and operating flexibility and good fuel economy at reasonable capital investment. To meet these requirements, a combined cycle arrangement was completed in 1978 utilizing one existing gas turbine-generator and one new gas turbine-generator, both exhausting to a new heat recovery steam generator which supplies steam to an existing steam turbine-generator. Damper controlled ducting directs exhaust gas from either gas turbine, one at a time, through the heat recovery steam generator. The existing oil-fired steam boiler remains available to power the steam turbine-generator independently or in parallel with the heat recovery steam generator. The gas turbines can operate either in simple cycle as peaking units or in combined cycle, one at a time, as base load units. This arrangement provides excellent operating reliability and flexibility, and the most favorable economics of all generating arrangements for the service required.


Author(s):  
B. M. Burnside

The concept of the dual pressure steam/pure organic hybrid immiscible liquid cycle applied to recover exhaust heat from gas turbines is extended to include organic mixtures. Thermodynamics of the resulting ternary working fluid cycle is presented. For the cycle arrangement analysed it is calculated that the ternary steam/nonane/decane cycle with the organic very nonane rich produces about 2% more work than the corresponding all steam cycle for a typical gas turbine exhaust temperature. It is estimated that this advantage can be raised to about 4% by adding additional heaters at the stack end of the heat recovery generator. The analysis shows that it is unnecessary to use a pure alkane organic. A mixture containing up to about 5% of alkanes with higher boiling points than nonane is adequate.


Author(s):  
Kenichiro Mochizuki ◽  
Satoshi Shibata ◽  
Umeo Inoue ◽  
Toshiaki Tsuchiya ◽  
Hiroko Sotouchi ◽  
...  

As the energy consumption has been increasing rapidly in the commercial sector in Japan, the market potential for the micro gas turbine is significant and it will be realized substantially if the thermal efficiency is improved. One of measures is to introduce the steam injection system using the steam generated by the heat recovery steam generator. Steam injection tests have been carried out using a micro gas turbine (Capstone C60). Test results showed that key performance parameters such as power output, thermal efficiency and emissions were improved by the steam injection. The stable operation of micro gas turbine with steam injection was confirmed under various operating conditions. Consequently, a micro gas turbine based co-generation package with steam injection driven by a heat recovery steam generator (HRSG) with supplementary firing is proposed.


Author(s):  
Qun Zheng ◽  
Minghong Li ◽  
Yufeng Sun

Thermodynamic performance of wet compression and regenerative (WCR) gas turbine are investigated in this paper. The regenerative process can be achieved by a gas/air (and steam) heat exchanger, a regenerator, or by a heat recovery steam generator and then the steam injected into the gas turbine. Several schemes of the above wet compression and regenerative cycles are computed and analyzed. The calculated results indicate that not only a significant specific power can be obtained, but also is the WCR gas turbine an economic competitive option of efficient gas turbines.


2013 ◽  
Vol 860-863 ◽  
pp. 1366-1369 ◽  
Author(s):  
Dan Dan Sun ◽  
Cheng Yang ◽  
Fei Zeng

Currently, there are many evaluation indexes for gas turbine-based combined cooling, heating and power (CCHP). In this paper, a multi-objective evaluation index (MEI) model was suggested and weight coefficients were considered in the model. The CCHP system evaluated in this study was composed of gas turbine + heat recovery steam generator (HRSG ) + LiBr absorption chiller. The gas turbine-based CCHP system was evaluated and the component capacity was optimized with the proposed MEI. The study provides a reference for the allocation and operation of gas turbine-based CCHP.


Author(s):  
P. J. Dechamps

The last decade has seen remarkable improvement in gas turbine based power generation technologies, with the increasing use of natural gas-fuelled combined cycle units in various regions of the world. The struggle for efficiency has produced highly complex combined cycle schemes based on heat recovery steam generators with multiple pressure levels and possibly reheat. As ever, the evolution of these schemes is the result of a technico-economic balance between the improvement in performance and the increased costs resulting from a more complex system. This paper looks from the thermodynamic point of view at some simplified combined cycle schemes based on the concept of water flashing. In such systems, high pressure saturated water is taken off the high pressure drum and flashed into a tank. The vapour phase is expanded as low pressure saturated steam or returned to the heat recovery steam generator for superheating, whilst the liquid phase is recirculated through the economizer. With only one drum and three or four heat exchangers in the boiler as in single pressure level systems, the plant might have a performance similar to that of a more complex dual pressure level system. Various configurations with flash tanks are studied based on commercially available 150 MW-class E-technology gas turbines and compared with classical multiple pressure level combined cycles. Reheat units are covered, both with flash tanks and as genuine combined cycles for comparison purposes. The design implications for the heat recovery steam generator in terms of heat transfer surfaces are emphasized. Off-design considerations are also covered for the flash based schemes, as well as transient performances of these schemes, because the simplicity of the flash systems compared to normal combined cycles significantly affects the dynamic behaviour of the plant.


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