scholarly journals Thermodynamic analysis of combined cycle plant operation as part of an energy-saving system based on an absorption bromide-lithium refrigerating machine

2020 ◽  
Vol 4 (4) ◽  
pp. 57-65
Author(s):  
L. V. Galimova ◽  
◽  
D. Z. Bairamov ◽  
Keyword(s):  
Thermodynamic Analysis ◽  
Exergy Analysis ◽  
Exergy Efficiency ◽  
Combined Cycle ◽  
Plant Operation ◽  
Operating Modes ◽  
System A ◽  
Combined Cycle Plant ◽  
Current Energy

The main directions of research of the current energy-generating system, taking into account its technical limitations, are optimization and forecasting based on the analysis of its operating modes. Thermodynamic analysis involves determining the efficiency of the system based on the research of exergy efficiency and exergy losses. In this project, we propose methodic and results of exergy analysis of combined cycle gas plant operation as an object of energy production, the efficiency which is provided by cooling the outdoor air using an absorption bromide-lithium refrigerating machine. Conducting exergy analysis for determination of exergy destruction allow to determine the potential for increasing the efficiency of the system. A flow graph and an incident matrix are presented. The exergy efficiency of the combined cycle gas plant under the specified conditions is 46,5%. Based on the exergy analysis, the final diagram of the distribution of fluxes and losses of exergy of the combined cycle gas plant is presented

Exergy Evaluation of Two Current Advanced Power Plants: Supercritical Steam Turbine and Combined Cycle

1997 ◽  
Vol 119 (4) ◽  
pp. 250-256 ◽  
Author(s):  
H. Jin ◽  
M. Ishida ◽  
M. Kobayashi ◽  
M. Nunokawa
Keyword(s):  
Steam Turbine ◽  
Thermal Efficiency ◽  
Heat Recovery ◽  
Power Plants ◽  
Exergy Analysis ◽  
Combined Cycle ◽  
Exergy Loss ◽  
Heat Recovery Steam Generator ◽  
Combined Cycle Plant ◽  
Steam Plant

Two operating advanced power plants, a supercritical steam plant and a gas-steam turbine combined cycle, have been analyzed using a methodology of graphical exergy analysis (EUDs). The comparison of two plants, which may provide the detailed information on internal phenomena, points out several inefficient segments in the combined cycle plant: higher exergy loss caused by mixing in the combustor, higher exergy waste from the heat recovery steam generator, and higher exergy loss by inefficiency in the power section, especially in the steam turbine. On the basis of these fundamental features of each plant, we recommend several schemes for improving the thermal efficiency of current advanced power plants.

Off-Design and Part-Load Behaviour of PFBC Combined Cycle Power Plant

1984 ◽  
Author(s):  
K. K. Pillai ◽  
A. G. Roberts
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
Combined Cycle ◽  
Fluidised Bed ◽  
Plant Operation ◽  
Combined Cycle Power Plant ◽  
Design Point ◽  
Commercial Plant ◽  
Start Up ◽  
Combined Cycle Plant

Combined cycle power plant utilising pressurised fluidised bed coal combustors (PFBCs) have, of necessity, to be designed to suit the particular gas turbine chosen. The gas turbine characteristics set not only the design point but also the turndown available. The interactions between the gas cycle, the combustor and the steam cycle are different to those normally associated with combined cycle plant. This paper describes the methods available when designing for plant operation at off-design conditions. It is shown how available techniques are capable of meeting commercial plant requirements for start-up, rates of load change and turndown.

Part-Load Limit Reduction of a Frame 9E Using a Precursor for Combustion Dynamics

2018 ◽  
Author(s):  
Driek Rouwenhorst ◽  
Robert Widhopf-Fenk ◽  
Jakob Hermann ◽  
Matthias Häringer ◽  
Julius Becker ◽  
...  
Keyword(s):  
Gas Turbines ◽  
Combined Cycle ◽  
Operating Costs ◽  
Limiting Factor ◽  
Combustion Dynamics ◽  
Part Load ◽  
Fuel Savings ◽  
Load Limit ◽  
Combined Cycle Plant

In a test campaign to lower the minimum part-load of a combined cycle plant, a series of turndown tests on two GE Frame 9E gas turbines with DLN1 combustor technology were carried out under premix operation by Stadtwerke München (SWM). It has been found that the load can be reduced significantly compared to the conventional turndown ratio, before either CO emissions or combustion dynamics form the limiting factor of the turndown test. To exploit this potential safely and operate the gas turbines close to these physical limits, emissions and combustion dynamics must be monitored online. The azimuthal thermoacoustic mode that is observed in the can-annular machines is monitored with the IfTA PreCursor, based on the online determination of the modal decay rate. For this method, the acoustic pressure is measured at the cans around the gas turbine circumference to observe the azimuthal acoustic propagation that is enabled by the cross-firing tubes between the cans. Using this strategy to monitor CO emissions and thermoacoustic stability in real-time, a reduction of the minimal part-load limit by approximately 20% is achieved for the considered gas turbines. In must-run situations without demand for electricity generation, the operating costs can be directly reduced by the fuel savings. As an additional benefit, SWM can offer a broader power reserve for grid stabilization on the energy market. This monitoring strategy has been fully implemented in the control system and first experiences of the extended part-load limit are currently being gathered.

Exergy Analysis of Thermal Energy Storage With Specific Remarks on the Variation of the Environmental Temperature

1996 ◽  
Vol 118 (2) ◽  
pp. 81-88 ◽  
Author(s):  
G. Bisio
Keyword(s):  
Energy Storage ◽  
Constant Temperature ◽  
Exergy Analysis ◽  
Environmental Temperature ◽  
Variable Temperature ◽  
Thermal Storage ◽  
Exergy Efficiency ◽  
Basic Question ◽  
Storage Devices ◽  
Temperature Environment

Energy storage is a key technology for many purposes and in particular for air conditioning plants and a successful exploitation of solar energy. Thermal storage devices are usually classified as either variable temperature (“sensible heat”) or constant temperature (“latent heat”) devices. For both models a basic question is to determine the efficiency suitably: Only exergy efficiency appears a proper way. The aim of this paper is to examine exergy efficiency in both variable and constant temperature systems. From a general statement of exergy efficiency by the present author, two types of actual definitions are proposed, depending on the fact that the exergy of the fluid leaving the thermal storage during the charge phase can be either totally lost or utilized elsewhere. In addition, specific remarks are made about the exergy of a system in a periodically varying temperature environment.

A Comparative Evaluation of Advanced Combined Cycle Alternatives

1991 ◽  
Vol 113 (2) ◽  
pp. 190-197 ◽  
Author(s):  
O. Bolland
Keyword(s):  
Heat Transfer ◽  
Steam Turbine ◽  
Comparative Evaluation ◽  
Exergy Analysis ◽  
Combined Cycle ◽  
Heat Transfer Area ◽  
Turbine Condenser ◽  
Pressure Cycle ◽  
Steam Turbine Condenser ◽  
Exergy Balance

This paper presents a comparison of measures to improve the efficiency of combined gas and steam turbine cycles. A typical modern dual pressure combined cycle has been chosen as a reference. Several alternative arrangements to improve the efficiency are considered. These comprise the dual pressure reheat cycle, the triple pressure cycle, the triple pressure reheat cycle, the dual pressure supercritical reheat cycle, and the triple pressure supercritical reheat cycle. The effect of supplementary firing is also considered for some cases. The different alternatives are compared with respect to efficiency, required heat transfer area, and stack temperature. A full exergy analysis is given to explain the performance differences for the cycle alternatives. The exergy balance shows a detailed breakdown of all system losses for the HRSG, steam turbine, condenser, and piping.

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