Optimal Configuration Design of Gas Turbine Cogeneration Plants by a MILP Decomposition Approach

Author(s):  
Ryohei Yokoyama

To attain the highest economic and energy saving characteristics of gas turbine cogeneration plants, it is necessary to rationally determine capacities and numbers of gas turbines and auxiliary equipment in consideration of their operational strategies corresponding to seasonal and hourly variations in energy demands. Some optimization approaches based on the mixed-integer linear programming (MILP) have been proposed to such configuration design problems of energy supply plants. However, with increases in the numbers of the equipment which must be considered as candidates as well as the periods which must be set for variations in energy demands, the optimal configuration design problems become too large-scale and complex to solve. The author has proposed a MILP decomposition approach to obtain quasi-optimal solutions of the optimal configuration design problems in reasonable computation times. However, this approach has been limited to the optimal configuration design problems where equipment capacities are treated continuously. In this paper, the MILP decomposition approach is extended to the optimal configuration design problems where equipment capacities are treated discretely. The effectiveness of this extended approach is investigated through a numerical study on a gas turbine cogeneration plant.

Author(s):  
Ryohei Yokoyama ◽  
Masashi Ohkura ◽  
Tetsuya Wakui

Some optimal operation methods based on the mixed-integer linear programming (MILP) have been proposed to operate energy supply plants properly from the viewpoints of economics, energy saving, and CO2 emission reduction. However, most of the methods are effective only under certain energy demands. In operating an energy supply plant actually, it is necessary to determine the operational strategy properly based on predicted energy demands. In this case, realized energy demands may differ from the predicted ones. Therefore, it is necessary to determine the operational strategy so that it is robust against the uncertainty in energy demands. In this paper, an optimization method based on the MILP is proposed to conduct the robust optimal operation of energy supply plants under uncertain energy demands. The uncertainty in energy demands is expressed by their intervals. The operational strategy is determined to minimize the maximum regret in the operational cost under the uncertainty. In addition, a hierarchical relationship among operation modes and on/off states of equipment, energy demands, and energy flow rates of equipment is taken into account. First, a general formulation of a robust optimal operation problem is presented, which is followed by a general solution procedure. Then, in a numerical study, the proposed method is applied to a gas turbine cogeneration plant for district energy supply. Through the study, some features of the robust optimal operation are clarified, and the validity and effectiveness of the proposed method are ascertained.


Author(s):  
Ryohei Yokoyama ◽  
Koichi Ito

A rational method of determining the operational strategy of energy supply plants in consideration of equipment startup/shutdown cost is proposed. The operational planning problem is formulated as a large-scale mixed-integer linear programming one, in which on/off status and energy flow rates of equipment are determined so as to minimize the sum of energy supply and startup/shutdown costs over the period considered. By utilizing a special structure of the problem, an algorithm of solving the problem efficiently is proposed. Through a numerical study on the daily operational planning of a gas turbine cogeneration plant for district heating and cooling, the effectiveness of the proposed algorithm is ascertained in terms of computation time, and the influence of equipment startup/shutdown cost on the operational strategy and cost is clarified.


Author(s):  
Tomoki Taniguchi ◽  
Ryoji Tamai ◽  
Yoshihiko Muto ◽  
Satoshi Takami ◽  
Ryozo Tanaka ◽  
...  

Kawasaki Heavy Industries, Ltd (KHI) has started a comprehensive program to further improve performance and availability of existing Kawasaki gas turbines. In the program, one of the Kawasaki’s existing gas turbine was selected from the broad product line and various kinds of technology were investigated and adopted to further improve its thermal performance and availability. The new technologies involve novel film cooling of turbine nozzles, advanced and large-scale numerical simulations, new thermal barrier coating. The thermal performance target is combined cycle efficiency of 51.6% and the target ramp rate is 20% load per minute. The program started in 2015 and engine testing has just started. In this paper, details of the program are described, focusing on design procedure.


Author(s):  
Glenn McAndrews

Electric starter development programs have been the subject of ASME technical papers for over two decades. Offering significant advantages over hydraulic or pneumatic starters, electric starters are now poised to be the preferred choice amongst gas turbine customers. That they are not now the dominant starter in the field after decades of investment and experimentation is attributable to many factors. As with any new technology, progress is often unsteady, depending on budgets, market conditions, customer buy-in, etc. Additionally, technological advances in the parent technologies, in this case electric motors, can abruptly and rapidly change, further disturbing the best laid introduction plans. It is therefore not too surprising that only recently, is the industry beginning to see the deployment of electric starters on production gas turbines. The earliest adoption occurred on smaller gas turbine units, generally less than 10 MW in power. More recently, gas turbines greater than 10 MWs are being sold with electric starters. The authors expect that regardless of their size or fuel supply, most all future gas turbine users will opt for electric starters. This may even include the “larger” frame machines with power greater than 100 MW. Starting with some past history, this paper will not only summarize past development efforts, it will attempt to examine the current deployment of electric starters throughout the marine and industrial gas turbine landscapes. The large-scale acceptance of electric start systems for both new production and retrofit will depend on the favorable cost/benefit assessment when weighing both first cost and life cycle cost. The current and intense activity in electric vehicle applications is giving rise to even more power dense motors. The paper will look at some of these exciting applications, the installed products, and the technologies behind the products. To what extent these new products may serve the needs of the gas turbine community will be the central question this paper attempts to answer.


Author(s):  
G. E. Parker

Controls for small lightweight gas turbines present some unique design problems. The requirements for small size, light weight, ability to rotate at high speeds to save reduction gearing, and low production cost conflict with the requirements for reasonably accurate control of very small fuel flows and the scheduling of a wide range of hydrocarbon fuels over a wide range of ambient temperatures. This paper discusses in some detail the design of such a control and the satisfactory results obtained.


1994 ◽  
Vol 116 (1) ◽  
pp. 32-38 ◽  
Author(s):  
R. Yokoyama ◽  
K. Ito ◽  
Y. Matsumoto

An optimal planning method is proposed for the fundamental design of cogeneration plants. Equipment capacities and utility maximum demands are determined so as to minimize the annual total cost in consideration of the plants’ annual operational strategies for the variations of both electricity and thermal energy demands. These sizing and operational planning problems are formulated as a nonlinear programming problem and a mixed-integer linear programming problem, respectively. They are solved efficiently in consideration of their hierarchical relationship by a penalty method. A numerical example about a gas turbine plant is given to ascertain the validity and effectiveness of the proposed method.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Vedant Dwivedi ◽  
Srikanth Hari ◽  
S. M. Kumaran ◽  
B. V. S. S. S. Prasad ◽  
Vasudevan Raghavan

Abstract Experimental and numerical study of flame and emission characteristics in a tubular micro gas turbine combustor is reported. Micro gas turbines are used for distributed power (DP) generation using alternative fuels in rural areas. The combustion and emission characteristics from the combustor have to be studied for proper design using different fuel types. In this study methane, representing fossil natural gas, and biogas, a renewable fuel that is a mixture of methane and carbon-dioxide, are used. Primary air flow (with swirl component) and secondary aeration have been varied. Experiments have been conducted to measure the exit temperatures. Turbulent reactive flow model is used to simulate the methane and biogas flames. Numerical results are validated against the experimental data. Parametric studies to reveal the effects of primary flow, secondary flow and swirl have been conducted and results are systematically presented. An analysis of nitric-oxides emission for different fuels and operating conditions has been presented subsequently.


2021 ◽  
Author(s):  
Davendu Y. Kulkarni ◽  
Gan Lu ◽  
Feng Wang ◽  
Luca di Mare

Abstract The gas turbine engine design involves multi-disciplinary, multi-fidelity iterative design-analysis processes. These highly intertwined processes are nowadays incorporated in automated design frameworks to facilitate high-fidelity, fully coupled, large-scale simulations. The most tedious and time-consuming step in such simulations is the construction of a common geometry database that ensures geometry consistency at every step of the design iteration, is accessible to multi-disciplinary solvers and allows system-level analysis. This paper presents a novel design-intent-driven geometry modelling environment that is based on a top-down feature-based geometry model generation method. In the proposed object-oriented environment, each feature entity possesses a separate identity, denotes an abstract geometry, and carries a set of characteristics. These geometry features are organised in a turbomachinery feature taxonomy. The engine geometry is represented by a tree-like logical structure of geometry features, wherein abstract features outline the engine architecture, while the detailed geometry is defined by lower-level features. This top-down flexible arrangement of feature-tree enables the design intent to be preserved throughout the design process, allows the design to be modified freely and supports the design intent variations to be propagated throughout the geometry automatically. The application of the proposed feature-based geometry modelling environment is demonstrated by generating a whole-engine computational geometry. This geometry modelling environment provides an efficient means of rapidly populating complex turbomachinery assemblies. The generated engine geometry is fully scalable, easily modifiable and is re-usable for generating the geometry models of new engines or their derivatives. This capability also enables fast multi-fidelity simulation and optimisation of various gas turbine systems.


Author(s):  
Weimar Mantilla ◽  
José García ◽  
Rafael Guédez ◽  
Alessandro Sorce

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.


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