scholarly journals PFA-linings for avoidance of dewpoint corrosion in heat-exchangers and ducts of waste-incineration power plants

2013 ◽  
Author(s):  
M. Lotz
Keyword(s):  
Heat Exchangers ◽  
Power Plants ◽  
Waste Incineration

ALLEGHENY LUDLUM AL 29-4C

Alloy Digest ◽  
1993 ◽  
Vol 42 (11) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Tensile Properties ◽  
Heat Exchangers ◽  
Power Plants ◽  
High Strength ◽  
Corrosion Resistant ◽  
Resistant Alloy ◽  
Corrosion Resistant Alloy ◽  
Geothermal Power

Abstract AL 29-4C is a highly corrosion resistant alloy with a relatively high strength. This combination allows the use of lighter gage tubes, and has led to its use in the brine heat exchangers of geothermal power plants. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming and joining. Filing Code: SS-554. Producer or source: Allegheny Ludlum Corporation.

scholarly journals Impacts of Water Flow Rate on Freezing Prevention of Air-Cooled Heat Exchangers in Power Plants

Energies ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 112 ◽  
Author(s):  
Yonghong Guo ◽  
Huimin Wei ◽  
Xiaoru Yang ◽  
Weijia Wang ◽  
Xiaoze Du ◽  
...  
Keyword(s):  
Water Flow ◽  
Flow Rate ◽  
Heat Exchangers ◽  
Power Plants ◽  
Water Flow Rate

RevospECT® PRO Software for Automated Interpretation of Results and Automatic Tracking of Defects during Eddy Current Inspection of Heat Exchangers

NDT World ◽  
2021 ◽  
pp. 21-23
Author(s):  
Denis Shorikov ◽  
Aleksandra Melnikova
Keyword(s):  
Eddy Current ◽  
Heat Exchangers ◽  
Nuclear Power ◽  
Power Plants ◽  
Level Ii ◽  
Unique System ◽  
Self Study ◽  
Software Product ◽  
Eddy Current Inspection ◽  
Automated Interpretation

The eddy current NDT method has been successfully used at Russian nuclear power plants for more than 20 years, but there are still problems with assessing the reliability of the results. Software product of Zetec Inc. (USA) RevospECT® Pro allows you to automatically analyze and compare the monitoring results of the same object, obtained at different times, which allows you to track the development of defects. Thanks to a unique system for collecting and analyzing information, its ability to self-study, RevospECT® Pro is able to make decisions on its own, replacing the level II specialist in full.

Recuperators in Gas Turbine Systems

1998 ◽  
Author(s):  
Esa Utriainen ◽  
Bengt Sundén
Keyword(s):  
Research And Development ◽  
Gas Turbine ◽  
Cross Sections ◽  
Heat Exchangers ◽  
Power Plants ◽  
Pressure Ratio ◽  
Compact Heat Exchangers ◽  
Thermodynamic Cycles ◽  
Large Pressure ◽  
Gas Turbine Cycle

The application of recuperators in advanced thermodynamic cycles is growing due to stronger demands of low emissions of pollutants and the necessity of improving the cycle efficiency of power plants to reduce the fuel consumption. This paper covers applications and types of heat exchangers used in gas turbine units. The trends of research and development are brought up and the future need for research and development is discussed. Material aspects are covered to some extent. Attempts to achieve compact heat exchangers for these applications are also discussed. With the increasing pressure ratio in the gas turbine cycle, large pressure differences between the hot and cold sides exist. This has to be accounted for. The applicability of CFD (Computational Fluid Dynamics) is discussed and a CFD–approach is presented for a specific recuperator. This recuperator has narrow wavy ducts with complex cross-sections and the hydraulic diameter is so small that laminar flow prevails. The thermal-hydraulic performance is of major concern.

An Assessment of the Performance of Closed Cycles With and Without Heat Rejection at Cryogenic Temperatures

1996 ◽  
Author(s):  
A. Agazzani ◽  
A. F. Massardo ◽  
T. Korakianitis
Keyword(s):  
Heat Exchangers ◽  
Power Plants ◽  
Cycle Performance ◽  
Maximum Temperature ◽  
Specific Work ◽  
Cryogenic Temperatures ◽  
Temperature Minimum ◽  
Thermodynamic Performance ◽  
Cycle Systems ◽  
Near Term

This paper presents optimized cycle performance that can be obtained with systems including a Closed Cycle Gas Turbine (CCGT). The influence of maximum temperature, minimum temperature and recuperator effectiveness on cycle performance is illustrated. Several power-plant arrangements are analyzed and compared based on: thermodynamic performance (thermal efficiency and specific work); enabling technologies (available at present); and developing technologies (available in the near term or future). The work includes the effects of utilization of high temperature ceramic heat exchangers and of coupling of CCGT systems with plants vaporizing Liquid Hydrogen (LH2) or Liquefied Natural Gas (LNG). Given the versatility of energy addition and rejection sources that can be utilized in closed gas-cycle systems, the thermodynamic performance of power plants shown in this paper indicate the remarkable capabilities and possibilities for closed gas-cycle systems.

scholarly journals Exergoeconomic and Normalized Sensitivity Analysis of Plate Heat Exchangers: A Theoretical Framework with Application

2021 ◽  
Author(s):  
Muhammad Ahmad Jamil ◽  
Talha S. Goraya ◽  
Haseeb Yaqoob ◽  
Kim Choon Ng ◽  
Muhammad Wakil Shahzad ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Heat Exchangers ◽  
Power Plants ◽  
Theoretical Framework ◽  
Plate Heat Exchanger ◽  
Sensitivity Analyses ◽  
Thermal Systems ◽  
Plate Heat ◽  
Economic Analyses ◽  
Exergoeconomic Analysis

Heat exchangers are the mainstay of thermal systems and have been extensively used in desalination systems, heating, cooling units, power plants, and energy recovery systems. This chapter demonstrates a robust theoretical framework for heat exchangers investigation based on two advanced tools, i.e., exergoeconomic analysis and Normalized Sensitivity Analysis. The former is applied as a mutual application of economic and thermodynamic analyses, which is much more impactful than the conventional thermodynamic and economic analyses. This is because it allows the investigation of combinatory effects of thermodynamic and fiscal parameters which are not achieved with the conventional methods. Similarly, the Normalized Sensitivity Analysis allows a one-on-one comparison of the sensitivity of output parameters to the input parameters with entirely different magnitudes on a common platform. This rationale comparison is obtained by normalizing the sensitivity coefficients by their nominal values, which is not possible with the conventional sensitivity analyses. An experimentally validated example of a plate heat exchanger is used to demonstrate the application of the proposed framework from a desalination system.

Research of Technology for Repair of Heat Exchangers of Nuclear Power Plants by Laser Welding

2021 ◽  
Vol 313 ◽  
pp. 94-105
Author(s):  
A. Bernatskyi ◽  
V. Sydorets ◽  
O.M. Berdnikova ◽  
I. Krivtsun ◽  
O. Kushnarova
Keyword(s):  
Service Life ◽  
Laser Welding ◽  
Welded Joints ◽  
Heat Exchangers ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Mechanical Test ◽  
Austenitic Steels ◽  
Depth Of Penetration

Extending the lifetime of energy facilities is extremely important today. This is especially true of nuclear power plants, the closure (or modernization) of which poses enormous financial and environmental problems. High-quality repair of reactors can significantly extend their service life. One of the critical parts is heat exchangers, the tubes of which quite often fail. Sealing, as a type of repair of heat exchanger tubes by the plugs, is promising provided that the joint quality is high. Practical experience in the use of welding to solve this problem has shown the need to search technological solutions associated with increasing the depth of penetration and reducing the area of thermal effect. The aim of the work was to develop a highly efficient technology for repair and extension of service life of heat exchangers of nuclear power plants based on the results of studying the technological features of laser welding of joints of dissimilar austenitic steels AISI 321 and AISI 316Ti in the vertical spatial position. Based on the results of the analysis of mechanical test data, visual and radiographic control, impermeability tests and metallographic studies of welded joints, the appropriate modes of laser welding of plugs have been determined. The principal causes of defects during laser welding of annular welded joints of dissimilar stainless steels are determined and techniques for their elimination and prevention of their formation are proposed. Based on the results of the research, technological recommendations for laser welding of plugs in the heat exchange tube of the collector are formulated, which significantly improves the technology of repair of steam generators of nuclear power plants and extends the service life of reactors.

scholarly journals OTEC Maximum Net Power Output Using Carnot Cycle and Application to Simplify Heat Exchanger Selection

Entropy ◽  
2019 ◽  
Vol 21 (12) ◽  
pp. 1143 ◽  
Author(s):  
Kevin Fontaine ◽  
Takeshi Yasunaga ◽  
Yasuyuki Ikegami
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Power Output ◽  
Heat Exchangers ◽  
Power Plants ◽  
Seawater Temperature ◽  
Carnot Cycle ◽  
Ocean Thermal Energy ◽  
Net Power Output

Ocean thermal energy conversion (OTEC) uses the natural thermal gradient in the sea. It has been investigated to make it competitive with conventional power plants, as it has huge potential and can produce energy steadily throughout the year. This has been done mostly by focusing on improving cycle performances or central elements of OTEC, such as heat exchangers. It is difficult to choose a suitable heat exchanger for OTEC with the separate evaluations of the heat transfer coefficient and pressure drop that are usually found in the literature. Accordingly, this paper presents a method to evaluate heat exchangers for OTEC. On the basis of finite-time thermodynamics, the maximum net power output for different heat exchangers using both heat transfer performance and pressure drop was assessed and compared. This method was successfully applied to three heat exchangers. The most suitable heat exchanger was found to lead to a maximum net power output 158% higher than the output of the least suitable heat exchanger. For a difference of 3.7% in the net power output, a difference of 22% in the Reynolds numbers was found. Therefore, those numbers also play a significant role in the choice of heat exchangers as they affect the pumping power required for seawater flowing. A sensitivity analysis showed that seawater temperature does not affect the choice of heat exchangers, even though the net power output was found to decrease by up to 10% with every temperature difference drop of 1 °C.

Analytical Evaluation of Unsteady Thermal Hydraulic Characteristics in Shell and Tube Heat Exchangers

2006 ◽  
Author(s):  
Shiro Takahashi ◽  
Yuichi Narumi ◽  
Kiyoshi Ishihama ◽  
Akihito Yokoyama ◽  
Toyohiko Tsuge ◽  
...  
Keyword(s):  
Heat Exchangers ◽  
Nuclear Power ◽  
Power Plants ◽  
Tube Bundle ◽  
Fluid Temperature ◽  
Detached Eddy Simulation ◽  
Tube Heat Exchanger ◽  
Eddy Simulation ◽  
Safety And Reliability ◽  
Cfd Analyses

Many shell & tube heat exchangers are used in nuclear power plants. Unsteady thermal hydraulic phenomena have been studied in shell & tube heat exchangers to improve their safety and reliability and to extend their lifetime based on experience obtained from long periods of plant operation. We investigated unsteady flow in shell & tube heat exchangers by using computational fluid dynamics (CFD) analyses. The inlet flow on the shell side was separated and flow in several directions. A large part of the flow crossed over the tube bundle, and some parts of the flow took two circuitous roots (up and down) along the inner surface of the shell. Separated circuitous flows collided again where a baffle plate had been cut off. A pair of symmetric vortexes could be seen in that location. Some parts of the circuitous flow moved backwards into the tube bundle due to vortexes. These vortexes were unstable and changed their size and location. A pair of vortexes changed from symmetric to asymmetric. As a result, the direction of flow in the tube bundle near the vortexes changed continuously. Variations in vortexes simulated through CFD analyses could also be seen in tests on the actual size. Fluid temperature fluctuations around tubes were also evaluated through CFD analyses. Unsteady phenomena with changes from symmetric to asymmetric vortexes could be observed in the shell & tube heat exchanger and were simulated through CFD analyses with a detached eddy simulation (DES) turbulence model.

scholarly journals Structural And Thermal Characteristics of Aluminum Grades 6063 and 7075 with Application of Nano Coatings

2018 ◽  
Vol 7 (2.32) ◽  
pp. 187
Author(s):  
Ch Sridhar Yesaswi ◽  
N Venkata Sai ◽  
K Vivek ◽  
B Raju ◽  
G Venkat
Keyword(s):  
Heat Exchangers ◽  
Power Plants ◽  
Material Selection ◽  
Structural Characteristics ◽  
Thermal Characteristics ◽  
Vital Role ◽  
Nano Particles ◽  
Technology Advancement ◽  
Nano Coating ◽  
Metal Pipes

To fabricate any product, material selection is one of the major constraints for many engineers even on today. An intensive research is being done by scientists and engineers over the properties and characteristics of the materials. Due to the technology advancement, applications of various new products are entering into market with different materials. From the past few decades composites and alloy materials are playing a vital role because of their unique nature. In the present work heat exchangers are taken into application. In nuclear and power plants heat exchangers plays a crucial role in cooling the reactors. When these are made to cool with water by sending through metal pipes over a period of time, metal pipes get easily corroded because of water and thermal conductivity of the metal. When base metals are coated with Nano-particles there is a drastic change in their behavior. In this paper Aluminum grade 6063 and grade 7075 are considered and coated with Al2O3-NaOH Nano fluids. Their thermal and structural characteristics are identified before and after Nano coating.    

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