scholarly journals Advanced Control to Improve the Ramp-Rate of a Gas Turbine: Optimization of Control Schedule

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8024
Author(s):  
Young-Kwang Park ◽  
Seong-Won Moon ◽  
Tong-Seop Kim
Keyword(s):  
Gas Turbines ◽  
Rotation Speed ◽  
Process Variable ◽  
Rate Of Change ◽  
Power Grids ◽  
Inlet Temperature ◽  
Ramp Rate ◽  
Set Point ◽  
Advanced Control ◽  
The Difference

As the proportion of power generation using renewable energy increases, it is important to improve the operational flexibility of gas turbines (GTs) for the stability of power grids. Increasing the ramp-rate of GTs is a general solution. However, a higher ramp-rate increases the turbine inlet temperature (TIT), its rate of change, and the fluctuation of the frequency of produced electricity, which are negative side effects. This study proposes a method to optimize the set-point schedule for a PID controller to improve the ramp-rate while decreasing the negative impacts. The set-point schedule was optimized for a 170-MW class GT using a genetic algorithm to minimize the difference between the value of the process variable and the set-point value of the conventional control. The advanced control reduced the fluctuation of the rotation speed by 20% at the reference ramp-rates (12 MW/min and 15 MW/min). The maximum TIT decreased by 6.3 °C, and its maximum rate of change decreased from 0.7 °C/s to 0.4 °C/s. The advantage of the advanced control becomes more marked as the ramp-rate increases. Even at a much higher ramp-rate (50 MW/min), the advanced control decreased the rotation speed fluctuation by 40% in comparison to the conventional control at the reference ramp-rate.

scholarly journals Advanced Gas Turbine Control Logic Using Black Box Models for Enhancing Operational Flexibility and Stability

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5703
Author(s):  
Seong Won Moon ◽  
Tong Seop Kim
Keyword(s):  
Gas Turbines ◽  
Black Box ◽  
Maximum Deviation ◽  
Inlet Temperature ◽  
Operational Flexibility ◽  
Control Logic ◽  
Ramp Rate ◽  
Box Models ◽  
Advanced Control ◽  
Black Box Models

In recent years, the importance of operational flexibility has increased for gas turbines that can stably operate under various operation conditions. This study proposes advanced control logic using black box models based on an artificial neural network. The goals are to enhance the operational flexibility by increasing the ramp rate and to enhance the operational stability by overcoming the limitation of conventional schedule-based control. By applying the advanced control logic, the turbine inlet temperature (TIT) and turbine exhaust temperature (TET) can be maintained at the optimal values, resulting in efficiency improvement by 0.35%. Furthermore, the maximum deviation of the rotational speed was reduced from 0.22% to 0.061%, and the maximum variations of TIT and TET were reduced by 15–20 °C during the fluctuation of the gas turbine’s power output. In conclusion, high-efficiency operation and a reduction in the degradation of the high-temperature parts can be expected through optimal operations of gas turbines by applying the proposed advanced control logic in a harsh operating environment. Moreover, fast load following can be achieved to meet the recent requirements of the operation environment of gas turbines by improving the ramp rate from 30 to 60 MW/min.

Micro Gas Turbine With Ceramic Rotor

2004 ◽  
Author(s):  
Hiro Yoshida ◽  
Takayuki Matsunuma ◽  
Norihiko Iki ◽  
Yoshio Akimune ◽  
Hiroshi Hoya
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Elevated Temperatures ◽  
Rotation Speed ◽  
Turbine Rotor ◽  
Bench Test ◽  
Inlet Temperature ◽  
Micro Gas Turbine ◽  
Basic Performance ◽  
Inconel 713C

A series of operation tests by using a desktop size gas turbine has been successfully carried out. In the first step of the tests, we have concentrated ourselves on the operation at elevated temperatures. Thus the duration of the bench test at each rotation speed was set to be 1 minute. The baseline machine is J-850 (Sophia Precision, Co., Ltd.) originally made for model airplanes. In this study, we replaced an INCONEL 713C alloy turbine rotor with 5.5 cm diameter into a type SN235 ceramic rotor (Kyocera Corporation). Mixture of 70% white kerosene and 30% gasoline was used as the fuel. The running test was made at the rotational speeds up to 140,000 r.p.m. in the atmospheric air. The basic performance of the small gas turbine was found as follows: At 140,000 r.p.m., 1) the turbine inlet temperature was estimated to be higher than 1,200. This estimation was supported by the observation of the partially melted INCONEL alloy nozzle located before the ceramic rotor. But the ceramic rotor revealed no damages. 2) The compression ratio and the thrust of the ceramic rotor turbine attained at 140,000 r.p.m. were 3 and 100 N, respectively. 3) Total energy level of the exhaust gas jet was 240 kW at the same rotation speed. Experiences learned from the present running tests suggest that the small gas turbine system employed in this study could be a useful tool to quicken the cycle of R & D of micro ceramic gas turbines with reasonable costs.

Control of an adiabatic continuous reactor by feeding catalyst

1980 ◽  
Vol 45 (11) ◽  
pp. 2903-2918 ◽  
Author(s):  
Josef Horák ◽  
Zina Valášková ◽  
František Jiráček
Keyword(s):  
Steady State ◽  
Reaction Temperature ◽  
Continuous Reactor ◽  
Control Element ◽  
Inlet Temperature ◽  
Switching Cycle ◽  
Point Temperature ◽  
Set Point ◽  
Constant Rate ◽  
Laboratory Reactor

Algorithms have been presented, analyzed and experimentally tested to stabilize the reaction temperature at constant inlet temperature and composition of the feed by controlled dispensing of the catalyst. The information for the control element is the course of the reaction temperature. If the temperature of the reaction mixture is below the set point, the catalyst is being fed into the reactor at a constant rate. If the reaction temperature is higher the catalyst dispenser is blocked; dispensing of the catalyst is not resumed until the set point temperature has been reached again. The amount of catalyst added is a function of the duration of the switching cycle. The effect has been discussed of the form of this function on the course of the switching cycle. The results have been tested experimentally on a laboratory reactor controlled in an unstable steady state.

scholarly journals Numerical Investigation of a Radially Cooled Turbine Guide Vane Using Air and Steam as a Cooling Medium

Computation ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 63
Author(s):  
Sondre Norheim ◽  
Shokri Amzin
Keyword(s):  
Numerical Model ◽  
Gas Turbines ◽  
Guide Vane ◽  
Axial Direction ◽  
Average Error ◽  
Inlet Temperature ◽  
Average Temperature ◽  
Cooling Medium ◽  
Turbine Guide Vane ◽  
Steam Cooling

Gas turbine performance is closely linked to the turbine inlet temperature, which is limited by the turbine guide vanes ability to withstand the massive thermal loads. Thus, steam cooling has been introduced as an advanced cooling technology to improve the efficiency of modern high-temperature gas turbines. This study compares the cooling performance of compressed air and steam in the renowned radially cooled NASA C3X turbine guide vane, using a numerical model. The conjugate heat transfer (CHT) model is based on the RANS-method, where the shear stress transport (SST) k−ω model is selected to predict the effects of turbulence. The numerical model is validated against experimental pressure and temperature distributions at the external surface of the vane. The results are in good agreement with the experimental data, with an average error of 1.39% and 3.78%, respectively. By comparing the two coolants, steam is confirmed as the superior cooling medium. The disparity between the coolants increases along the axial direction of the vane, and the total volume average temperature difference is 30 K. Further investigations are recommended to deal with the local hot-spots located near the leading- and trailing edge of the vane.

Comparison of Transient Modeling Techniques for a Micro Turbine Engine

2006 ◽  
Author(s):  
Craig R. Davison ◽  
A. M. Birk
Keyword(s):  
Gas Turbines ◽  
Relative Size ◽  
Rate Of Change ◽  
Single Stage ◽  
Radial Compression ◽  
Shaft Speed ◽  
Transient Effects ◽  
Rates Of Change ◽  
Experimental Apparatus ◽  
Transient Modeling

A large number of papers have been published on transient modeling of large industrial and military gas turbines. Few, however, have examined micro turbines. The decrease in size affects the relative rates of change of shaft speed, gas dynamics and heat soak. This paper compares the modeled transient effects of a micro turbojet engine comprised of a single stage of radial compression and a single stage of axial expansion, with a diameter of 12cm. The model was validated with experimental data. Several forms of the model were produced starting with the shaft and fuel transients. Conservation of mass, and then energy, was subsequently added for the compressor, combustor and turbine, and a large inlet plenum that was part of the experimental apparatus. Heat soak to the engine body was incorporated into both the shaft and energy models. Heat soak was considered in the compressor, combustor and turbine. Since the engine diameter appears in the differential equations to different powers, the relative rates of change vary with diameter. The rate of change of shaft speed is very strongly influenced. The responses of the different transient effects are compared. The relative solution times are also discussed, since the relative size of the required time steps changes when compared to a large engine.

scholarly journals Composite Distribution Solution for Minimizing Heat Loss in a Pyrolysis Reactor

2011 ◽  
Vol 9 (1) ◽  
Author(s):  
Werner O. Filtvedt ◽  
Morten Melaaen ◽  
Arve Holt ◽  
Massoud Javidi ◽  
Birger Retterstøl Olaisen
Keyword(s):  
Heat Loss ◽  
Reaction Chamber ◽  
Inlet Temperature ◽  
Chemical Reactors ◽  
Normal Procedure ◽  
Pyrolysis Reactor ◽  
The Difference ◽  
Distribution Plate ◽  
Composite Distribution ◽  
Novel Design

The article presents a novel design for a distribution plate. The solution is suitable for a reactor vessel where a reactant gas needs to be maintained at a different temperature from the reaction chamber in order to avoid unwanted occurrences, such as clogging of the distribution plate. A normal procedure involves cooling of the distribution plate which is reported to either increase heat loss substantially or yield insufficient temperature in parts of the reaction chamber. The problem is especially important for reactors where the difference in reactant inlet temperature and desired reaction temperature is large. The investigated design utilized materials of very different thermal conductivity to only cool specific parts of the distribution arrangement and thereby minimize heat loss. Our system is a distribution plate for use in a fluidized bed reactor for silane pyrolysis. However, the solution is general and may be utilized in many types of vessels and chemical reactors.

Development and Fabrication of Silicon Nitride Components for Ceramic Gas Turbine

1997 ◽  
Author(s):  
Keisuke Makino ◽  
Ken-Ichi Mizuno ◽  
Toru Shimamori
Keyword(s):  
High Temperature ◽  
Silicon Nitride ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Turbine Blades ◽  
High Strength ◽  
Inlet Temperature ◽  
Turbine Inlet Temperature ◽  
Spark Plug ◽  
Power Turbine

NGK Spark Plug Co., Ltd. has been developing various silicon nitride materials, and the technology for fabricating components for ceramic gas turbines (CGT) using theses materials. We are supplying silicon nitride material components for the project to develop 300 kW class CGT for co-generation in Japan. EC-152 was developed for components that require high strength at high temperature, such as turbine blades and turbine nozzles. In order to adapt the increasing of the turbine inlet temperature (TIT) up to 1,350 °C in accordance with the project goals, we developed two silicon nitride materials with further unproved properties: ST-1 and ST-2. ST-1 has a higher strength than EC-152 and is suitable for first stage turbine blades and power turbine blades. ST-2 has higher oxidation resistance than EC-152 and is suitable for power turbine nozzles. In this paper, we report on the properties of these materials, and present the results of evaluations of these materials when they are actually used for CGT components such as first stage turbine blades and power turbine nozzles.

Design Analysis of a Micro Gas Turbine Combustion Chamber Burning Natural Gas

2012 ◽  
Author(s):  
André Perpignan V. de Campos ◽  
Fernando L. Sacomano Filho ◽  
Guenther C. Krieger Filho
Keyword(s):  
Experimental Data ◽  
Natural Gas ◽  
Combustion Chamber ◽  
Gas Turbines ◽  
Low Cost ◽  
Mixture Fraction ◽  
Combustion Model ◽  
Inlet Temperature ◽  
Gas Combustion ◽  
Micro Turbine

Gas turbines are reliable energy conversion systems since they are able to operate with variable fuels and independently from seasonal natural changes. Within that reality, micro gas turbines have been increasing the importance of its usage on the onsite generation. Comparatively, less research has been done, leaving more room for improvements in this class of gas turbines. Focusing on the study of a flexible micro turbine set, this work is part of the development of a low cost electric generation micro turbine, which is capable of burning natural gas, LPG and ethanol. It is composed of an originally automotive turbocompressor, a combustion chamber specifically designed for this application, as well as a single stage axial power turbine. The combustion chamber is a reversed flow type and has a swirl stabilized combustor. This paper is dedicated to the diagnosis of the natural gas combustion in this chamber using computational fluid dynamics techniques compared to measured experimental data of temperature inside the combustion chamber. The study emphasizes the near inner wall temperature, turbine inlet temperature and dilution holes effectiveness. The calculation was conducted with the Reynolds Stress turbulence model coupled with the conventional β-PDF equilibrium along with mixture fraction transport combustion model. Thermal radiation was also considered. Reasonable agreement between experimental data and computational simulations was achieved, providing confidence on the phenomena observed on the simulations, which enabled the design improvement suggestions and analysis included in this work.

Part-Load Operation of Gas Turbines Induced by Co-Gasification of Coal and Biomass in an Integrated Gasification Combined Cycle Power Plant

2021 ◽  
Author(s):  
Silvia Ravelli
Keyword(s):  
Power Plant ◽  
Gas Turbines ◽  
Combined Cycle ◽  
Inlet Guide Vane ◽  
Inlet Temperature ◽  
Fuel Quality ◽  
Integrated Gasification Combined Cycle ◽  
Part Load ◽  
Wide Range ◽  
Integrated Gasification

Abstract This study takes inspiration from a previous work focused on the simulations of the Willem-Alexander Centrale (WAC) power plant located in Buggenum (the Netherlands), based on integrated gasification combined cycle (IGCC) technology, under both design and off-design conditions. These latter included co-gasification of coal and biomass, in proportions of 30:70, in three different fuel mixtures. Any drop in the energy content of the coal/biomass blend, with respect to 100% coal, translated into a reduction in gas turbine (GT) firing temperature and load, according to the guidelines of WAC testing. Since the model was found to be accurate in comparison with operational data, here attention is drawn to the GT behavior. Hence part load strategies, such as fuel-only turbine inlet temperature (TIT) control and inlet guide vane (IGV) control, were investigated with the aim of maximizing the net electric efficiency (ηel) of the whole plant. This was done for different GT models from leading manufactures on a comparable size, in the range between 190–200 MW. The influence of fuel quality on overall ηel was discussed for three binary blends, over a wide range of lower heating value (LHV), while ensuring a concentration of H2 in the syngas below the limit of 30 vol%. IGV control was found to deliver the highest IGCC ηel combined with the lowest CO2 emission intensity, when compared not only to TIT control but also to turbine exhaust temperature control, which matches the spec for the selected GT engine. Thermoflex® was used to compute mass and energy balances in a steady environment thus neglecting dynamic aspects.

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