scholarly journals Improvement of efficiency of detecting vacuum leakages by using combined methods

Vestnik IGEU ◽  
2021 ◽  
pp. 13-21
Author(s):  
A.D. Vodeniktov ◽  
V.G. Vlasenko ◽  
N.D. Chichirova
Keyword(s):  
Steam Turbine ◽  
Thermal Imaging ◽  
Power Plants ◽  
High Efficiency ◽  
Ultrasonic Method ◽  
Cost Effective ◽  
Steam Pressure ◽  
Operating Conditions ◽  
Vacuum System ◽  
Imaging Method

Trouble-free operation of the main equipment of heat power plants is determined by the performance reliability of condensing units. High air density of the vacuum system provides cost-effective and reliable operation. One of the reasons that causes an increase of the exhaust steam pressure compared to the standard pressure, in addition to contamination of the condensers cooling surface, is the high amount of air inflow through vacuum system leakiness. Exceeding the amount of atmospheric air inflow into the vacuum system above the standard value, both reduces the available heat energy and make worse the deaeration capacity of the condenser. This results in saturation of the full-flow condensate with oxygen and intensification of corrosion processes. Various methods varying in both cost and efficiency are used to find air inflow location. Nowadays, the issue of choosing a method to detect even the most insignificant air inflow location of the vacuum system of a steam turbine remains open. In the current study, the authors have used the thermal-imaging method to detect air inflow location due to local hypocooling, and the ultrasonic method, which is based on the detection of ultrasound created by gas flows. The authors have proved the necessity to use several different in concept methods to find leakage locations in a vacuum system. It is established that traditional methods to find vacuum system leaks do not allow to eliminate excess leaks. In-service monitoring confirms 87 % reduction of the amount of vacuum leaks. The studies show high efficiency of sharing both thermal imaging and ultrasonic methods to detect air inflow location in a vacuum system. According to the operating conditions of the available equipment, as well as the personnel qualifications, the results obtained make it possible to choose the most optimal way in terms of financial and time expenses to find vacuum leakage location in the vacuum system of a steam turbine.

Generalized Regeneration Theory and its Energy Saving and Emission Reduction Effects on Coal-Fired Power Generation

2016 ◽  
Author(s):  
Weizhong Feng
Keyword(s):  
Power Plants ◽  
High Efficiency ◽  
Steam Pressure ◽  
Combustion Efficiency ◽  
Operating Conditions ◽  
Low Oxygen ◽  
Material Technology ◽  
Boiler Operation ◽  
Combustion Technology ◽  
Reduce Emissions

Concerns related to global warming and environmental pollution concerns have pressured coal-fired power plants to improve efficiency and reduce emissions. However, the conventional efficiency improvement methods — increasing steam pressure and temperature and reducing condenser pressure are limited by material technology and the temperature of the available cooling medium. The next step for increasing efficiency would be to add additional reheat or regenerative cycles, but this is not feasible for existing plants. In addition, as the share of renewable energy and the grid’s demands on the coal-fired power plants increases, China’s coal-fired units are faced with more and tougher challenges, including large peak-valley gaps, frequent startups and shutdowns and cost pressures. As a result, the boiler combustion efficiency decreases and incidents such as furnace explosions, aggravation and collapsing of slag and burning of facilities located downstream of the economizer become more frequent. To address these problems, the generalized regeneration theory has been proposed and a series of related technologies have been developed, providing a new approach for not only improving the efficiency of coal-fired power plants, but also resulted in boiler operation that is cleaner and safer. These technologies which include anew boiler startup technology, the high efficiency combustion and low emission technology under low load and the low oxygen, and a low NOx and high efficiency combustion technology under high load have been implemented successfully in the Shanghai Waigaoqiao No. 3 power plant. By improving the utilization of turbine extraction and reducing the exhaust loss, these innovative technologies greatly improve the environmental performance, efficiency and safety of the units in various operating conditions. In addition, improvements have been made in the boilers ability to adapt to changing coal supplies, particularly for coal with high slagging tendencies and high moisture content.

"Recent Patents on the Triboelectrostatic Separation of Fly Ash"

2019 ◽  
Vol 13 ◽  
Author(s):  
Haisheng Li ◽  
Wenping Wang ◽  
Yinghua Chen ◽  
Xinxi Zhang ◽  
Chaoyong Li
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
High Efficiency ◽  
Separation Efficiency ◽  
High Reliability ◽  
Operating Conditions ◽  
Security Requirements ◽  
Unburned Carbon ◽  
Efficient Operation ◽  
Triboelectrostatic Separation

Background: The fly ash produced by coal-fired power plants is an industrial waste. The environmental pollution problems caused by fly ash have been widely of public environmental concern. As a waste of recoverable resources, it can be used in the field of building materials, agricultural fertilizers, environmental materials, new materials, etc. Unburned carbon content in fly ash has an influence on the performance of resource reuse products. Therefore, it is the key to remove unburned carbon from fly ash. As a physical method, triboelectrostatic separation technology has been widely used because of obvious advantages, such as high-efficiency, simple process, high reliability, without water resources consumption and secondary pollution. Objective: The related patents of fly ash triboelectrostatic separation had been reviewed. The structural characteristics and working principle of these patents are analyzed in detail. The results can provide some meaningful references for the improvement of separation efficiency and optimal design. Methods: Based on the comparative analysis for the latest patents related to fly ash triboelectrostatic separation, the future development is presented. Results: The patents focused on the charging efficiency and separation efficiency. Studies show that remarkable improvements have been achieved for the fly ash triboelectrostatic separation. Some patents have been used in industrial production. Conclusion: According to the current technology status, the researches related to process optimization and anti-interference ability will be beneficial to overcome the influence of operating conditions and complex environment, and meet system security requirements. The intelligent control can not only ensure the process continuity and stability, but also realize the efficient operation and management automatically. Meanwhile, the researchers should pay more attention to the resource utilization of fly ash processed by triboelectrostatic separation.

Validation of Advanced Steam Turbine Technology: A Case Study of an Ultra Super Critical Steam Turbine Power Plant

2011 ◽  
Author(s):  
Rainer Quinkertz ◽  
Thomas Thiemann ◽  
Kai Gierse
Keyword(s):  
High Pressure ◽  
Power Plant ◽  
Steam Turbine ◽  
Power Plants ◽  
High Efficiency ◽  
State Of The Art ◽  
Cooling System ◽  
Operational Experience ◽  
Internal Cooling ◽  
Steam Turbines

High efficiency and flexible operation continue to be the major requirements for power generation because of the benefits of reduced emissions and reduced fuel consumption, i.e. reduced operating costs. Ultra super critical (USC) steam parameters are the basis for state of the art technology of coal fired power plants with highest efficiency. An important part of the development process for advanced steam turbines is product validation. This step involves more than just providing evidence of customer guaranteed values (e.g. heat rate or electric output). It also involves proving that the design targets have been achieved and that the operational experience is fed back to designers to further develop the design criteria and enable the next step in the development of highly sophisticated products. What makes product validation for large size power plant steam turbines especially challenging is the fact that, due to the high costs of the required infrastructure, steam turbine manufacturers usually do not have a full scope / full scale testing facility. Therefore, good customer relations are the key to successful validation. This paper describes an extensive validation program for a modern state of the art ultra supercritical steam turbine performed at an operating 1000 MW steam power plant in China. Several measuring points in addition to the standard operating measurements were installed at one of the high pressure turbines to record the temperature distribution, e.g. to verify the functionality of the internal cooling system, which is an advanced design feature of the installed modern high pressure steam turbines. Predicted 3D temperature distributions are compared to the actual measurements in order to verify and evaluate the design rules and the design philosophy applied. Conclusions are drawn regarding the performance of modern 3D design tools applied in the current design process and an outlook is given on the future potential of modern USC turbines.

scholarly journals Evaluation of Property Methods for Modeling Direct-Supercritical CO2 Power Cycles

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Charles W. White ◽  
Nathan T. Weiland
Keyword(s):  
Power Plants ◽  
Physical Property ◽  
Aspen Plus ◽  
Cost Effective ◽  
Operating Conditions ◽  
Working Fluid ◽  
Power Cycles ◽  
As Species ◽  
Cost Effective Method ◽  
Open Nature

Direct supercritical carbon dioxide (sCO2) power cycles are an efficient and potentially cost-effective method of capturing CO2 from fossil-fueled power plants. These cycles combust natural gas or syngas with oxygen in a high pressure (200–300 bar), heavily diluted sCO2 environment. The cycle thermal efficiency is significantly impacted by the proximity of the operating conditions to the CO2 critical point (31 °C, 73.7 bar) as well as to the level of working fluid dilution by minor components, thus it is crucial to correctly model the appropriate thermophysical properties of these sCO2 mixtures. These properties are also important for determining how water is removed from the cycle and for accurate modeling of the heat exchange within the recuperator. This paper presents a quantitative evaluation of ten different property methods that can be used for modeling direct sCO2 cycles in Aspen Plus®. Reference fluid thermodynamic and transport properties (REFPROP) is used as the de facto standard for analyzing high-purity indirect sCO2 systems, however, the addition of impurities due to the open nature of the direct sCO2 cycle introduces uncertainty to the REFPROP predictions as well as species that REFPROP cannot model. Consequently, a series of comparative analyses were performed to identify the best physical property method for use in Aspen Plus® for direct-fired sCO2 cycles. These property methods are assessed against several mixture property measurements and offer a relative comparison to the accuracy obtained with REFPROP. The Lee–Kessler–Plocker equation of state (EOS) is recommended if REFPROP cannot be used.

Development of LP Blade Module for High Back Pressure-Aerodynamic Design

2017 ◽  
Author(s):  
Ambrish ◽  
Nand Kumar Singh
Keyword(s):  
Steam Turbine ◽  
Power Plants ◽  
Volume Flow Rate ◽  
Back Pressure ◽  
Operating Conditions ◽  
Total Efficiency ◽  
Aerodynamic Design ◽  
Streamline Curvature ◽  
Pressure Application ◽  
Wide Range

In steam turbine power plants, the appropriate design of the last stage blades is critical in determining the plant efficiency and reliability. The development of LP module for desert applications is finding applications for a number of industrial steam turbine operating with air cooled condensers. The conventional LP Module for water cooled condenser operates at low back pressure (Pexit = 0.09 bar) and are generally not suitable for high back pressure application. This paper focuses on the aerodynamic design & optimization of last stages of LP blade module for high back pressure application and validation through 3D CFD. The guide and moving blade are designed with seven equally-spaced profiles section from hub to shroud through Axstream S/w. The profile and incidence losses are minimized for the design and off-design conditions. Aeromechanical design of LP blade module consisting of 2 stages for 0.2 bar back pressure, 1.1 bar inlet static pressure and a mass flow of 61.2 kg/s is carried out. An optimization process through a streamline curvature code and design optimization software using Optimus is established and flow path contours is optimized thoroughly, a total to total efficiency of 81.4% is achieved for the rated condition. The off-design performance is investigated for a wide range of operating conditions, especially at low volume flow rate of steam condition.

Improvement in Recuperative Gas Cycles by Means of a Heat Generator Partly By-Passing the Recuperator: Application to Open and Closed Cycles and to Various Kinds of Energy

1979 ◽  
Author(s):  
Z. P. Tilliette ◽  
B. Pierre
Keyword(s):  
Power Plants ◽  
High Efficiency ◽  
Primary Energy ◽  
Operating Conditions ◽  
Heat Output ◽  
Medium Temperature ◽  
Heat Generator ◽  
High Temperature Process ◽  
Temperature Heat ◽  
Operation Flexibility

A particular arrangement applicable to open or closed recuperative gas cycles, consisting of a heat generator partly by-passing the low pressure side of the recuperator, is proven to enhance the advantages of gas cycles for energy production. In this way, the cogeneration of both power with high efficiency owing to the recuperator and high temperature process heat becomes possible and economically attractive. Furthermore, additional possibilities appear for power generation by combined gas and steam or ammonia cycles. In any case, the overall utilitization coefficient of the primary energy is increased and the combined production of low or medium temperature heat can also be improved. The great operation flexibility of the system for combined energy generation is worth being emphasized: the by-pass arrangement involves no significant change in the operating conditions of the main turbocompressor as the heat output varies. Applications of this arrangement are made to open and closed gas cycle power plants using fossil, nuclear and solar energies. The overall heat conversion efficiency is tentatively estimated in order to appreciate the energy conversion capability of the investigated power plants.

Development of High Efficiency MCFC/GT Hybrid Power Generation System

2003 ◽  
Author(s):  
T. Watanabe ◽  
Y. Izaki ◽  
Y. Mugikura ◽  
M. Yoshikawa ◽  
H. Morita ◽  
...  
Keyword(s):  
Power Plants ◽  
High Efficiency ◽  
Low Voltage ◽  
Operating Conditions ◽  
Performance Estimation ◽  
Estimation Methods ◽  
Central Research ◽  
Molten Carbonate ◽  
Initial Development ◽  
Hybrid Power

A number of cycle simulations, which are applied by Molten Carbonate Fuel Cell (MCFC) power plants combined with gas/steam turbines, prove that it is possible to design very highly efficient power plants. However, the stack performance, the operation technology and the performance estimation technology have not yet been established during the initial development stages. The Central Research Institute of Electric Power Industry (CRIEPI) has performed many cell and stack tests and has evaluated the performance under various operating conditions. The operation, performance analysis and estimation methods have been developed for various pressure ranges. Therefore, the accuracy of the plant power estimation has been improved immensely. CRIEPI has also proposed the application of a Li/Na electrolyte instead of a Li/K to achieve higher voltages and a longer stack life. A 10 kW-class short stack consisting of ten 1-m2 cells with a Li/Na electrolyte was operated for more than 10,000 hours, and a very low voltage decay rate was measured during the governmental program. Based on these accomplishments, field tests on small MCFC/GT (gas turbine) hybrid power plants with capacities of several hundred kW will be initiated in Japan throughout the next years.

Gasdynamic Design Numerical Optimization of High-Loaded Subsonic Stages for Low Pressure Steam Turbine

2013 ◽  
Author(s):  
Aleksei Dolganov ◽  
Alexander Nekrasov
Keyword(s):  
Steam Turbine ◽  
Power Plants ◽  
High Efficiency ◽  
Low Pressure ◽  
Large Capacity ◽  
Low Pressure Turbine ◽  
Relative Pitch ◽  
Pressure Steam ◽  
Basic Characteristics

Modern large capacity steam turbine for fossil power plants should have a high efficiency to be competitive in today’s tough market. It should be compact, with a smaller mass for reducing cost. In these circumstances, an effective solution is to create a large capacity steam turbine that consists of integrated high-intermediate-pressure turbine (HIPT) and one low-pressure turbine (LPT). Greater heat drop as compared to a conventional turbine shall be provided in LPT of such steam turbine. With this rather high efficiency of the low-pressure turbine should be provided. The performance of LPT depends not only on the efficiency of trans- and supersonic stages, but also on the efficiency of subsonic upstream stages. At a time when the overall heat drop in the low-pressure turbine is increased, role of the upstream subsonic stages also increases, provided that the design of stages L-0 and L-1 is maintained. This paper presents results of numerical simulation of an optimized subsonic stages section for a new low-pressure steam turbine. Simulation results of a conventional subsonic stages section are presented for comparison. Stages of the optimized subsonic section have a number of features: increased disposable heat drop, enlarged relative pitch, spline representation of sections of blade profiles, 3D airfoil design. The comparison of normalized integral basic characteristics, plots of the main parameters on the blade height, diagrams of the normalized pressure in individual cylindrical sections is given for optimized and conventional cases.

scholarly journals Cost-effective removal of COD in the pre-treatment of wastewater from the paper industry

2019 ◽  
Vol 81 (7) ◽  
pp. 1345-1353 ◽  
Author(s):  
Joanna Boguniewicz-Zablocka ◽  
Iwona Klosok-Bazan ◽  
Vincenzo Naddeo ◽  
Clara A. Mozejko
Keyword(s):  
Wastewater Treatment ◽  
High Efficiency ◽  
Paper Industry ◽  
Cost Effective ◽  
Operating Conditions ◽  
Cod Removal ◽  
Process Efficiency ◽  
Effective Removal ◽  
Initial Ph ◽  
Pre Treatment

Abstract The present paper reveals results of research for cost-effective removal of chemical oxygen demand (COD) contained in industrial paper mill effluent. Not only process efficiency but also wastewater treatment costs are discussed. Different pre-treatment processes are applied aiming to investigate the COD removal before discharge to the municipal sewage network. The objective of this paper is to find the optimal operating conditions for the coagulation process. The effects of key operational parameters, including the type of coagulant, initial pH, temperature and coagulant dose, on COD percentage removal were investigated. The laboratory experiments confirmed the high efficiency of chemically enhanced mechanical treatment towards COD. The data obtained show that even low dose of chemicals provides sufficient COD reduction. The initial pH of the wastewater had a significant impact on the COD removal. Under the optimal operational conditions (pH = 7.5, T = 18 °C) the treatment of wastewater from paper industries by coagulation has led to a reduction of 70% COD for wastewater discharged. In terms of the investigated paper industry wastewater, polyaluminium chloride appears to be most suitable for treatment of high COD concentration. However, in an economic evaluation of requirements for wastewater treatment, operating costs and associated saving were such that PAX was more favourable.

The Influence of Cooling Flows on the Operating Conditions of the Ultra-Supercritical Steam Turbine Components

2010 ◽  
Author(s):  
Wojciech Kosman
Keyword(s):  
Numerical Modeling ◽  
Steam Turbine ◽  
Power Plants ◽  
Measurement Data ◽  
Test Stand ◽  
Operating Conditions ◽  
Temperature Fields ◽  
Inlet Section ◽  
Steam Turbines ◽  
Cooling Flows

This paper presents the results of the analysis on the heat transfer in the inlet section of an ultra-supercritical steam turbine. Such power generating units become the foundation of new coal-fired power plants. The monitoring of their operation is in many aspects similar to the traditional, sub-critical steam turbines. However, higher live and reheat steam parameters result in several key differences, which must be taken into the consideration when assessing the thermal and strength states of the turbines main components for the diagnostic supervision. One of the main differences is the presence of the cooling and designs specific for ultra-supercritical steam turbines, which aim to protect their components against overheating. The research described in this paper investigates the inlet section of the turbines, which is the area exposed to the highest thermal loads. The scope of the research includes both, numerical modeling and laboratory testing. A test stand has been built for the analysis of the flows in the inlet section. Cooling flows are under special attention here as their temperature field is coupled to the temperature fields of the turbine components (the rotor and the inner casing) due to the relatively small amount of the coolant. The paper provides detailed description of the test stand and some early measurement results, which involve the operation with cooling. Also the numerical modeling results are shown and compared to the measurement data.

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