scholarly journals Problem of maintaining a normal condensate dissolved oxygen concentration

2022 ◽  
Vol 2150 (1) ◽  
pp. 012010
Author(s):  
A D Vodeniktov ◽  
N D Chichirova
Keyword(s):  
Dissolved Oxygen ◽  
Water Temperature ◽  
Oxygen Concentration ◽  
Normal Level ◽  
Power Plants ◽  
Cooling Water ◽  
Air Leakage ◽  
Dissolved Oxygen Concentration ◽  
Cooling Water Temperature

Abstract Study presents the results of the steam surface KCS-200-2 reconstruction. In order to maintain the dissolved oxygen concentration, according to the Code of Operation for Power Plants, the steam sparger was installed in condenser hotwell. Despite the abnormal air leakage level, reducing of dissolved oxygen concentration was reached. The dissolved oxygen concentration reduced, on average, by 2 times. As it was expected, in the cases of low inlet cooling water temperature, the final oxygen concentration did not reach the normal level. In last 3 tests the dissolved oxygen concentration was reduced to 19 mg /l. The results show a possibility of described reconstruction experience.

scholarly journals Nest-site selection in a fish species with paternal care

Hydrobiologia ◽  
2020 ◽  
Author(s):  
Theo C. M. Bakker ◽  
Beat Mundwiler
Keyword(s):  
Dissolved Oxygen ◽  
Water Temperature ◽  
Oxygen Concentration ◽  
Fish Species ◽  
Nest Site ◽  
Paternal Care ◽  
Small Fish ◽  
Dissolved Oxygen Concentration ◽  
Nest Sites ◽  
Higher Temperature

AbstractFish that perform paternal care may increase their fitness by choosing nest sites that enhance survival and development of embryos. We studied nest-site choice with respect to dissolved oxygen concentration and water temperature in males of the three-spined stickleback (Gasterosteus aculeatus), a small fish species with exclusive male parental care that usually breeds in the littoral zone of freshwaters of the Northern hemisphere. Fathers oxygenate the embryos by fanning movements of their pectoral fins. We expected choice for conditions at potential nest sites that would benefit offspring development, i.e., higher temperature and higher dissolved oxygen concentration. In the laboratory, we offered males a choice between two potential nest sites that differed in dissolved oxygen concentration or water temperature. Males preferred to build a nest at sites with a higher dissolved oxygen level or higher temperature and thus chose sites that would promote embryo development.

Formulation of Film Theory Equations for Modeling of Condensation of Steam-Air Mixtures in a Shell and Tube Condenser

2008 ◽  
Author(s):  
Yousef Haseli ◽  
Ibrahim Dincer ◽  
Greg F. Naterer
Keyword(s):  
Water Temperature ◽  
Film Theory ◽  
Cooling Water ◽  
Air Leakage ◽  
Condensation Rate ◽  
Shell Side ◽  
Pressure Drops ◽  
Cooling Water Temperature ◽  
Temperature And Pressure ◽  
Tube Condenser

Through development of the fundamental equations of Film Theory, condensation of steam in the presence of air in a horizontal counter-current shell and one-path tube condenser is modeled. The interaction between heat and mass transfer and hydrodynamics in the shell-side is taken into consideration. A comparison between the predictions of the model and a set of experimental data available in the archival literature indicates excellent accuracy of the new formulation. The accuracy of the method is further validated by generating profiles of the temperature and pressure drops of the gas flow through the baffles, at various air leakages. Additionally, the effects of air leakage and upstream cooling water temperature are investigated to determine how they influence the total condensation rate, shell-side gas temperature and pressure drops. The results show that the total condensation rate decreases 5% and 20.5% for an air leakage of 1% and 5%, respectively, compared to the situation of pure vapor. Also, increasing the inlet cooling water temperature from 46.5°C to 48.5°C leads to 16.2% reduction in the total condensation rate, i.e., 8.1% per °C. However, this ratio is higher at high temperatures. For example, as the cooling water temperature rises from 50°C to 51°C under identical process conditions, the total condensation rate decreases 11.7% (per °C).

Hot Water Etching of Silicon Surfaces: New Insights of Mechanistic understanding and Implications to Device Fabrication

1997 ◽  
Vol 477 ◽  
Author(s):  
J. M. Rosamilia ◽  
T. Boone ◽  
J. Sapjeta ◽  
K. Raghavachari ◽  
G. S. Higashi ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Water Temperature ◽  
Oxygen Concentration ◽  
Etch Rate ◽  
Hot Water ◽  
Surface Erosion ◽  
Rate Data ◽  
Dissolved Oxygen Concentration ◽  
Rinse Water ◽  
Water Rinsing

ABSTRACTOver the recent years, many new approaches in wafer cleaning have utilized hot water rinsing. Benefits of hot water rinsing are (1) it aids the removal of residual chemicals and (2) it improves the performance of the dry, e.g. TREBOR hydrodry. However, there have been a number of significant disadvantages documented with regard to device performance. Earlier work done at this laboratory showed that the use of DI rinse water at elevated temperatures can cause etching of the Si surface producing unwanted surface topography and microroughness. The surface erosion created under these conditions had a negative device impact which led to product yield loss. In this paper, we provide a fundamental understanding of the mechanism by which Si is etched during hot water rinsing. To this end, we have explored the interaction of dissolved oxygen concentration, water temperature, and rinse time as it relates to the attack/dissolution of H-terminated silicon. Contact angle measurements, surface roughness measurements, and etch rate data from TEM measurements as a function of water temperature, rinse time, and dissolved oxygen concentration have been made. The etch rate data strongly correlates with the rinse water temperature, however little dependence was observed with dissolved oxygen concentration. A mechanism to explain the etching will be discussed.

Optimum Condenser Cooling Water Temperature Rise in Power Plants

2003 ◽  
Author(s):  
Ram Srinivasan
Keyword(s):  
Power Plant ◽  
Water Temperature ◽  
Steam Turbine ◽  
Temperature Rise ◽  
Power Plants ◽  
Cooling Water ◽  
Design Parameters ◽  
Plant Design ◽  
Optimum Temperature ◽  
Cooling Water Temperature

The concept of optimum cooling water temperature rise in a power plant has been introduced in this study as that which corresponds to the highest possible net plant output. Every power plant having a steam turbine exhausting to a water-cooled condenser has a unique optimum cooling water temperature rise. This optimum temperature rise may not be the minimum possible as often inadvertently assumed by power plant designers. This optimum temperature rise is a strong function of the steam turbine exhaust parameters. The author has developed correlations, which will help determine the optimum temperature rise using easily available power plant design parameters. This paper will discuss the details behind this method and show the thermal and financial advantages of designing a plant with this concept. A proper understanding of this concept will enable power plant designers to economically and efficiently size the condenser cooling water system.

scholarly journals Impact of the cold end operating conditions on energy efficiency of the steam power plants

2010 ◽  
Vol 14 (suppl.) ◽  
pp. 53-66 ◽  
Author(s):  
Mirjana Lakovic ◽  
Mladen Stojiljkovic ◽  
Slobodan Lakovic ◽  
Velimir Stefanovic ◽  
Dejan Mitrovic
Keyword(s):  
Energy Efficiency ◽  
Power Plant ◽  
Water Temperature ◽  
Flow Rate ◽  
Power Plants ◽  
Cooling Water ◽  
Operating Conditions ◽  
Steam Boiler ◽  
Steam Power ◽  
Cooling Water Temperature

The conventional steam power plant working under the Rankine Cycle and the steam condenser as a heat sink and the steam boiler as a heat source have the same importance for the power plant operating process. Energy efficiency of the coal fired power plant strongly depends on its turbine-condenser system operation mode. For the given thermal power plant configuration, cooling water temperature or/and flow rate change generate alterations in the condenser pressure. Those changes have great influence on the energy efficiency of the plant. This paper focuses on the influence of the cooling water temperature and flow rate on the condenser performance, and thus on the specific heat rate of the coal fired plant and its energy efficiency. Reference plant is working under turbine-follow mode with an open cycle cooling system. Analysis is done using thermodynamic theory, in order to define heat load dependence on the cooling water temperature and flow rate. Having these correlations, for given cooling water temperature it is possible to determine optimal flow rate of the cooling water in order to achieve an optimal condensing pressure, and thus, optimal energy efficiency of the plant. Obtained results could be used as useful guidelines in improving existing power plants performances and also in design of the new power plants. <br><br><font color="red"><b> This article has been corrected. Link to the correction <u><a href="http://dx.doi.org/10.2298/TSCI151102198E">10.2298/TSCI151102198E</a><u></b></font>

scholarly journals Investigating the dearating hotwell working regimes of the PT-60-130/13 steam turbine

2021 ◽  
Vol 22 (6) ◽  
pp. 155-163
Author(s):  
A. D. Vodeniktov ◽  
N. D. Chihirova
Keyword(s):  
Dissolved Oxygen ◽  
Steam Turbine ◽  
Oxygen Concentration ◽  
Power Plants ◽  
Electrical Power ◽  
Dissolved Oxygen Concentration ◽  
Thermal Tests ◽  
Thermal Test ◽  
Turbine Condenser ◽  
Steam Turbine Condenser

THE PURPOSE. To consider the problems of the increasing dissolved oxygen concentration in feedwater, especially after the condensate pumps. To estimate the opportunity of the vacuum thermic deaeration intensification inside the PT-60-130/13 LMZ steam turbine condenser to reduce the feedwater system rate of corrosion. Perform a thermal test of the external deaerating hotwell, which provides reducing dissolved oxygen concentration by the hot drains and recirculating feedwater. To evaluate the march of the dissolved oxygen concentration in feedwater after the inclusion of the deaerating hotwell. METHODS. The thermal test of the external deaerating hotwell was chosen for evaluating water deaeration. RESULTS. In this paper, the results of the thermal tests are given. The relation of the dissolved oxygen concentration from heating fluid flow is also presented. CONCLUSION. The use of the external deaerating hotwell allows achieving dissolved oxygen concentration below the norms established by the сode of operation for electrical power plants and grids to ensure the maintenance of an acceptable water-chemical regime of the feedwater. During the tests, the dissolved oxygen concentration decreased by 70% and reached a value of 8 mcg/dm3. The deaerating hotwell of the considered type can be recommended for the operation, especially during start-up modes and modes with the low thermal load on the condenser cooling surface.

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