Part Load Behavior Optimization of Hybrid Coal and Gas Fired Combined Cycles Including Deactivation of Components

2002 ◽  
Author(s):  
Janpeter Ku¨hnel ◽  
Reza S. Abhari
Keyword(s):  
Power Plant ◽  
Objective Function ◽  
Gas Turbine ◽  
Mixed Integer ◽  
Operation Strategy ◽  
Part Load ◽  
Optimization Parameters ◽  
Cycle Efficiency ◽  
Load Behavior ◽  
Fuel Costs

This paper presents a methodology to optimize the part load behavior of complex power plant cycles. As free optimization parameters the traditional continuous control parameter and the activation/deactivation of defined plant components are considered resulting in a mixed integer non-linear programming problems (MINLP). The procedure starts with a continuous process on either side of the non-linearity in part load, while refining the steps as it approaches the discontinuity. It is shown that good convergence around the non-linearity can be found with the present scheme. For part load operation a number of continuous and binary free optimization parameters are available creating a challenging optimization problem. The developed procedure is applied to a conventional steam cycle power plant, which is parallel repowered with a modern gas turbine. The resulting power plant layout is a hybrid coal and gas fired combined cycle. As objective function the maximized overall thermal efficiency and the minimized fuel costs are two examples chosen. Investigating the minimized fuel costs as the objective function the optimized operation strategy is found to be an unique function of the fuel price ratio between coal and gas for the chosen layout. Finally we show, that the operation strategy can be notably improved by considering the deactivation of cycle components for minimizing the fuel costs and for maximizing the cycle efficiency. For example the cycle efficiency can be improved up to 2% by deactivating the high pressure feed water preheating. The fuel costs are reduced by 20% for a particular load point by deactivating the gas turbine.

Part-Load Behavior of a Solar-Heated and Fossil-Fueled Gas Turbine Power Plant

1987 ◽  
Vol 109 (1) ◽  
pp. 64-70 ◽  
Author(s):  
K. Bammert ◽  
H. Lange
Keyword(s):  
Power Plant ◽  
Power Transmission ◽  
Mechanical Energy ◽  
Radiant Energy ◽  
Radiant Heat ◽  
Hybrid Plant ◽  
Inlet Temperature ◽  
Part Load ◽  
Transmission Grid ◽  
Load Behavior

Solar energy can be converted effectively into electrical or mechanical energy. The radiant heat of the sun is collected by a parabolic dish, concentrated intensely, and reflected into a cavity receiver. Air flowing through tube panels in front of the receiver inner walls absorbs the radiant energy. Downstream of the receiver is a fossil-fired combustion chamber (hybrid construction). The fuel energy is converted at a higher utilization than in a straight fossil-fueled power plant. The overall efficiency of the hybrid plant rises with increasing turbine inlet temperature. The power delivered by the turbine serves to drive the compressor and the generator. A description of the thermodynamic design of the cycle is followed by statements on the performance characteristics of the individual components and by a description of the steady-state part-load behavior of the plant considering specific conditions such as variations in solar and fossil fuel-generated heat and fluctuating load on the power transmission grid.

Short-Term Optimization of a Combined Cycle Power Plant Integrated With an Inlet Air Conditioning Unit

2020 ◽  
Author(s):  
Weimar Mantilla ◽  
José García ◽  
Rafael Guédez ◽  
Alessandro Sorce
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Air Conditioning ◽  
Combined Cycle ◽  
Plant Performance ◽  
Mixed Integer ◽  
Environmental Load ◽  
Turbine Inlet ◽  
The Impact

Abstract Under new scenarios with high shares of variable renewable electricity, combined cycle gas turbines (CCGT) are required to improve their flexibility, in terms of ramping capabilities and part-load efficiency, to help balance the power system. Simultaneously, liberalization of electricity markets and the complexity of its hourly price dynamics are affecting the CCGT profitability, leading the need for optimizing its operation. Among the different possibilities to enhance the power plant performance, an inlet air conditioning unit (ICU) offers the benefit of power augmentation and “minimum environmental load” (MEL) reduction by controlling the gas turbine inlet temperature using cold thermal energy storage and a heat pump. Consequently, an evaluation of a CCGT integrated with this inlet conditioning unit including a day-ahead optimized operation strategy was developed in this study. To establish the hourly dispatch of the power plant and the operation mode of the inlet conditioning unit to either cool down or heat up the gas turbine inlet air, a mixed-integer linear optimization (MILP) was formulated using MATLAB, aiming to maximize the operational profit of the plant within a 24-hours horizon. To assess the impact of the proposed unit operating under this dispatch strategy, historical data of electricity and natural gas prices, as well as meteorological data and CO2 emission allowances price, have been used to perform annual simulations of a reference power plant located in Turin, Italy. Furthermore, different equipment capacities and parameters have been investigated to identify trends of the power plant performance. Lastly, a sensitivity analysis on market conditions to test the control strategy response was also considered. Results indicate that the inlet conditioning unit, together with the dispatch optimization, increases the power plant’s operational profit by achieving a wider operational range, particularly important during peak and off-peak periods. For the specific case study, it is estimated that the net present value of the CCGT integrated with the ICU is 0.5% higher than the power plant without the unit. In terms of technical performance, results show that the unit reduces the minimum environmental load by approximately 1.34% and can increase the net power output by 0.17% annually.

Part-Load Behavior of a Solar-Heated and Fossil-Fuelled Gas Turbine Power Plant

1986 ◽  
Author(s):  
K. Bammert ◽  
H. Lange
Keyword(s):  
Power Plant ◽  
Power Transmission ◽  
Mechanical Energy ◽  
Radiant Energy ◽  
Radiant Heat ◽  
Hybrid Plant ◽  
Inlet Temperature ◽  
Part Load ◽  
Transmission Grid ◽  
Load Behavior

Solar energy can be converted effectively into electrical or mechanical energy. The radiant heat of the sun is collected by a parabolic dish, concentrated intensely and reflected into a cavity receiver. Air flowing through tube panels in front of the receiver inner walls absorbs the radiant energy. Downstream of the receiver is a fossil-fired combustion chamber (hybrid construction). The fuel energy is converted at a higher utilization than in a straight fossil-fuelled power plant. The overall efficiency of the hybrid plant rises with increasing turbine inlet temperature. The power delivered by the turbine serves to drive the compressor and the generator. A description of the thermodynamic design of the cycle is followed by statements on the performance characteristics of the individual components and by a description of the steady-state part-load behavior of the plant considering specific conditions such as variations in solar and fossil fuel-generated heat and fluctuating load on the power transmission grid.

Sizing of a Gas Turbine for Repowering of Cogeneration Power Plant Ljubljana by Mathematical Optimisation

1996 ◽  
Author(s):  
Mihael Gabriel Tomšič ◽  
Olgica Perović
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
Optimal Operation ◽  
Hot Water ◽  
Mixed Integer ◽  
Heat Recovery Boiler ◽  
Continuous Variables ◽  
District Heating System ◽  
Operational Strategy ◽  
Steam Extraction

The paper deals with optimal sizing of a gas turbine for repowering of cogeneration power plant Ljubljana considering possible plant operational strategy with respect to variations of electric and heat loads and energy costs. CHP plant is a main source for the Ljubljana town district heating system. Existing plant consists of two condensing steam turbines with steam extraction, back pressure turbine with steam extraction, auxiliary steam and hot water boilers for peak heat load production. This system delivers up to 111 MW into the power grid and up to 348 MW of heat. Repowering with gas turbine generator set with additionally fired heat recovery boiler is considered. For uncoupling heat and power generation a heat storage tank is assumed. For sizing of new equipment and plant operational strategy a model based on mixed-integer linear programming was developed. Zero - one integer variables are adopted to indicate the on/off status of operation, continuous variables to indicate the operational level of each constituent equipment and an optimal solution is derived by branch and bound method. Two prospective sizes of TG sets were tested for range of assumptions regarding power purchase tariff schedules. Different optimal operation policies resulted. The study provides background for contract negotiation and for investment decisions.

Gas Turbine Airflow Control for Optimum Heat Recovery

1983 ◽  
Vol 105 (1) ◽  
pp. 72-79 ◽  
Author(s):  
W. I. Rowen ◽  
R. L. Van Housen
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Guide Vane ◽  
Control Mode ◽  
Cycle Performance ◽  
Inlet Guide Vane ◽  
Part Load ◽  
Exhaust Temperature ◽  
Cycle Efficiency

Gas turbines furnished with heat recovery equipment generally have maximum cycle efficiency when the gas turbine is operated at its ambient capability. At reduced gas turbine output the cycle performance can fall off rapidly as gas turbine exhaust temperature drops, which reduces the heat recovery equipment performance. This paper reviews the economic gains which can be realized through use of several control modes which are currently available to optimize the cycle efficiency at part load operation. These include variable inlet guide vane (VIGV) control for single-shaft units, and combined VIGV and variable high-pressure set (compressor) speed control for two-shaft units. In addition to the normal control optimization mode to maintain the maximum exhaust temperature, a new control mode is discussed which allows airflow to be modulated in response to a process signal while at constant part load. This control feature is desirable for gas turbines which supply preheated combustion air to fired process heaters.

General Method for the Development of Gas Turbine Based Plant Simulators: An IGCC Application

2013 ◽  
Author(s):  
Giovanni Cerri ◽  
Leila Chennaoui
Keyword(s):  
Power Plant ◽  
Energy Conversion ◽  
Gas Turbine ◽  
Plant Part ◽  
Physical Models ◽  
Part Load ◽  
Design Component ◽  
Component Sizing ◽  
Load Analysis ◽  
General Method

An Energy Conversion Power Plant Simulator development is presented. The various aspects related to the identification of the problem to be solved (cycle calculation, component sizing, off-design component behaviour, components matching and Plant part load analysis) are discussed. Mathematical aspects are illustrated and the components physical models are discussed. Examples for validation purposes are shown. An application to the development of a Generic 300 MW F Class Gas Turbine to be fed with H2 Rich Syngas produced by an IGCC is illustrated.

Bypass Control of Closed-Cycle Gas Turbines

1978 ◽  
Author(s):  
G. Krey
Keyword(s):  
Control System ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Closed Cycle ◽  
Part Load ◽  
Control Behavior ◽  
Bypass Valve ◽  
Load Behavior

The layout of the bypass control system of a closed-cycle gas turbine depends on the steady and nonsteady part-load behavior of the plant. In the paper, the results of investigations into the operating behavior of closed-cycle gas turbines are summarized. From these a method of laying out the bypass valve is deduced. Finally, an advanced bypass control system is described and the control behavior achievable therewith is explained.

Heat Exchanger Design Considerations for Gas Turbine HTGR Power Plant

1977 ◽  
Vol 99 (2) ◽  
pp. 237-245 ◽  
Author(s):  
C. F. McDonald ◽  
T. Van Hagan ◽  
K. Vepa
Keyword(s):  
Heat Exchanger ◽  
Power Plant ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Power Conversion ◽  
Structural Safety ◽  
Working Fluid ◽  
Closed Cycle ◽  
High Degree ◽  
Cycle Efficiency

The Gas Turbine High Temperature Gas Cooled Reactor (GT-HTGR) power plant combines the existing design HTGR core with a closed-cycle helium gas turbine power conversion system directly in the reactor primary circuit. Unlike open-cycle gas turbines where the recuperative heat exchanger is an optional component, the high cycle efficiency of the nuclear closed-cycle gas turbine is attributable to a high degree to the incorporation of the recuperator (helium-to-helium) and precooler (helium-to-water) exchangers in the power conversion loop. For the integrated plant configuration, a nonintercooled cycle with a high degree of heat recuperation was selected on the basis of performance and economic optimization studies. A recuperator of high effectiveness was chosen because it significantly reduces the optimum pressure ratio (for maximum cycle efficiency), and thus reduces the number of compressor and turbine stages for the low molecular weight, high specific heat, helium working fluid. Heat rejection from the primary system is effected by a helium-to-water precooler, which cools the gas to a low level prior to compression. The fact that the rejection heat is derived from the sensible rather than the latent heat of the cycle working fluid results in dissipation over a wide band of temperature, the high average rejection temperature being advantageous for either direct air cooling or for generation of power in a waste heat cycle. The high heat transfer rates in the recuperator (3100 MWt) and precooler (1895 MWt), combined with the envelope restraints associated with heat exchanger integration in the prestressed concrete reactor vessel, require the use of more compact surface geometries than in contemporary power plant steam generators. Various aspects of surface geometry, flow configuration, mechanical design, fabrication, and integration of the heat exchangers are discussed for a plant in the 1100 MWe class. The influence of cycle parameters on the relative sizes of the recuperator and precooler are also presented. While the preliminary designs included are not meant to represent final solutions, they do embody features that satisfy many of the performance, structural, safety, and economic requirements.

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