scholarly journals Study of the work and efficiency improvement of combined-cycle gas turbine plants

2019 ◽  
Vol 124 ◽  
pp. 05061 ◽  
Author(s):  
D.I. Mendeleev ◽  
Yu Ya Galitskii ◽  
G.E. Marin ◽  
A.R. Akhmetshin

The purpose of the paper is to study and analyze the possibility of increasing the power output of a combined-cycle gas turbine (CCGT) unit during the period of positive ambient temperatures. The first task is to analyze the operation of a 110 MW combined-cycle power unit at various ambient temperatures and to obtain alterations in the main CCGT characteristics when the ambient temperature changes. The other task is to study the usage of an absorption refrigeration machine in a CCGT cycle to increase its energy efficiency. Calculations of the thermal scheme of a gas turbine were carried out using mathematical modeling, the steam turbine was calculated based on guidelines. The conducted studies allow to conclude that the use of an absorption refrigeration machine in the cycle of a combined-cycle plant can improve the efficiency of the unit, increasing profits from power generation, and reducing penalties for non-compliance with the load schedule.

1996 ◽  
Vol 118 (3) ◽  
pp. 565-571 ◽  
Author(s):  
M. Nakhamkin ◽  
E. C. Swensen ◽  
J. M. Wilson ◽  
G. Gaul ◽  
M. Polsky

This paper introduces the Cascaded Humidified Advanced Turbine (CHAT) plant, a gas turbine based power generation plant utilizing intercooling, reheat, and humidification. It is based upon the integration of an existing heavy duty gas turbine with an additional shaft comprising industrial compressors and high pressure expander. CHAT capitalizes on the latest proven gas turbine technology, which, combined with a sophisticated thermal cycle configuration, results in substantial improvement in gas turbine efficiency, compared to a simple cycle, while still maintaining typical advantages and merits of a combustion turbine plant. Built with a commercial combustion turbine and available industrial compressors and expanders, the CHAT plant does not require extensive product development and testing. As a result, the CHAT power plant can be offered with specific capital costs up to 20 percent lower than the combined cycle plant, and with competing efficiency. Compared to a combined cycle plant, the CHAT plant offers lower emissions (due to air humidification) and other significant operating advantages with regard to start-up time and costs, better efficiency at part load, lower power degradation at higher ambient temperatures, and simpler operations and maintenance due to elimination of the complexities and costs associated with steam production. The CHAT plant also integrates very effectively with coal gasification and particularly well with the water quench design. This feature has been discussed in previous publications.


Author(s):  
Edgar Vicente Torres González ◽  
Raúl Lugo Leyte ◽  
Martín Salazar Pereyra ◽  
Helen Denise Lugo Méndez ◽  
Miguel Toledo Velázquez ◽  
...  

In this paper is carried out a comparison between a gas turbine power plant and a combined cycle power plant through exergetic and environmental indices in order to determine performance and sustainability aspects of a gas turbine and combined cycle plant. First of all, an exergetic analysis of the gas turbine and the combined is carried out then the exergetic and environmental indices are calculated for the gas turbine (case A) and the combined cycle (case B). The exergetic indices are exergetic efficiency, waste exergy ratio, exergy destruction factor, recoverable exergy ratio, environmental effect factor and exergetic sustainability. Besides, the environmental indices are global warming, smog formation and acid rain indices. In the case A, the two gas turbines generate 278.4 MW; whereas 415.19 MW of electricity power is generated by the combined cycle (case B). The results show that exergetic sustainability index for cases A and B are 0.02888 and 0.1058 respectively. The steam turbine cycle improves the overall efficiency, as well as, the reviewed exergetic indexes. Besides, the environmental indices of the gas turbines (case A) are lower than the combined cycle environmental indices (case B), since the combustion gases are only generated in the combustion chamber.


Author(s):  
M. W. Horner ◽  
A. Caruvana

Final component and technology verification tests have been completed for application to a 2600°F rotor inlet temperature gas turbine. These tests have proven the capability of combustor, turbine hot section, and IGCC fuel systems and controls to operate in a combined cycle plant burning a coal-derived gas fuel at elevated gas turbine inlet temperatures (2600–3000°F). This paper presents recent test results and summarizes the overall progress made during the DOE-HTTT Phase II program.


Author(s):  
Tadashi Tsuji

Air cooling blades are usually applied to gas turbines as a basic specification. This blade cooling air is almost 20% of compressor suction air and it means that a great deal of compression load is not converted effectively to turbine power generation. This paper proposes the CCM (Cascade Cooling Module) system of turbine blade air line and the consequent improvement of power generation, which is achieved by the reduction of cooling air consumption with effective use of recovered heat. With this technology, current gas turbines (TIT: turbine inlet temperature: 1350°C) can be up-rated to have a relative high efficiency increase. The increase ratio has a potential to be equivalent to that of 1500°C Class GT/CC against 1350°C Class. The CCM system is designed to enable the reduction of blade cooling air consumption by the low air temperature of 15°C instead of the usual 200–400°C. It causes the turbine operating air to increase at the constant suction air condition, which results in the enhancement of power and thermal efficiency. The CCM is installed in the cooling air line and is composed of three stage coolers: steam generator/fuel preheater stage, heat exchanger stage for hot water supplying and cooler stage with chilled water. The coolant (chilled water) for downstream cooler is produced by an absorption refrigerator operated by the hot water of the upstream heat exchanger. The proposed CCM system requires the modification of cooling air flow network in the gas turbine but produces the direct effect on performance enhancement. When the CCM system is applied to a 700MW Class CC (Combined Cycle) plant (GT TIT: 135°C Class), it is expected that there will be a 40–80MW increase in power and +2–5% relative increase in thermal efficiency.


Author(s):  
S. Can Gülen

Duct firing in the heat recovery steam generator (HRSG) of a gas turbine combined cycle power plant is a commonly used method to increase output on hot summer days when gas turbine airflow and power output lapse significantly. The aim is to generate maximum possible power output when it is most needed (and, thus, more profitable) at the expense of power plant heat rate. In this paper, using fundamental thermodynamic arguments and detailed heat and mass balance simulations, it will be shown that, under certain boundary conditions, duct firing in the HRSG can be a facilitator of efficiency improvement as well. When combined with highly-efficient aeroderivative gas turbines with high cycle pressure ratios and concomitantly low exhaust temperatures, duct firing can be utilized for small but efficient combined cycle power plant designs as well as more efficient hot-day power augmentation. This opens the door to efficient and agile fossil fuel-fired power generation opportunities to support variable renewable generation.


Author(s):  
A. Zwebek ◽  
P. Pilidis

This paper describes the effects of degradation of the main gas path components of the gas turbine topping cycle on the Combined Cycle Gas Turbine (CCGT) plant performance. Firstly the component degradation effects on the gas turbine performance as an independent unit are examined. It is then shown how this degradation is reflected on a steam turbine plant of the CCGT and on the complete Combined Cycle plant. TURBOMATCH, the gas turbine performance code of Cranfield University was used to predict the effects of degraded gas path components of the gas turbine have on its performance as a whole plant. To simulate the steam (Bottoming) cycle, another Fortran code was developed. Both codes were used together to form a complete software system that can predict the CCGT plant design point, off-design, and deteriorated (due to component degradation) performances. The results show that the overall output is very sensitive to many types of degradation, specially in the turbine of the gas turbine. Also shown is the effect on gas turbine exhaust conditions and how this affects the steam cycle.


1983 ◽  
Vol 105 (4) ◽  
pp. 870-874
Author(s):  
D. W. Leffler ◽  
B. S. Roberts

This paper discusses the evaluation, design, and operation of a combined-cycle plant for Bahamas Electricity Corporation in Nassau, Bahamas. The plant was designed to provide maximum fuel efficiency, satisfactorily operate to 40 percent load, and includes provisions for heavy oil firing in the gas turbine. The system was started up July, 1982 and has been in successful operation since then.


Author(s):  
Hossin Omar ◽  
Mohamed Elmnefi

The Pressurized Fluidized Circulating Bed (PFCB) combined cycle was simulated. The simulations balance the energy between the elements of the unit, which consists of gas turbine cycle and steam turbine cycle. The PFCB is used as a combustor and steam generator at the same time. The simulations were carried out for PFCB combined cycle plant for two cases. In the first case, the simulations were performed for combined cycle with reheat in the steam turbine cycle. While in the second case, the simulations were carried out for the PFCB combined cycle with extra combustor and steam turbine cycle with reheat. For both cases, the effect of steam inlet pressure on the combined cycle efficiency was predicted. It was found that increasing of steam pressure results in increase in the combined cycle thermal efficiency. The effect of the inlet flue gases temperature on the gas turbine and on the combined cycle efficiencies was also predicted. The maximum PFCB combined cycle efficiency occurs at a compression ratio of 18, which is the case of utilizing an extra combustor. The simulations were carried out for only one fuel composition and for a compression ratio ranges between 1 to 40.


Author(s):  
Atsuo Okubo ◽  
Yoshitaka Mori ◽  
Yoshikazu Nadai ◽  
Hiroshi Kanki

This paper describes the vibration analysis technology of MW-701D Gas Turbine which was developed by Mitsubishi Heavy Industries, Ltd. for 50 Hz utilities. MW-701D is the highest performance gas turbine available with a firing temperature of 1,154°C for base load operation. It is employed by the 1,090 MW combined cycle plant, one of the largest of its kind in the world, and the plant began commercial operation at half of the total capacity of 1,090 MW in December, 1984. The plant was designed to supply base load electric power generation by burning imported liquefied natural gas (LNG) fuel. This paper describes the general description of the combined cycle plant and the vibration characteristics of MW-701D Gas Turbine.


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