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In the construction process of mass concrete structures, the large temperature gradient due to exothermic hydration makes the mass concrete highly susceptible to cracking. This paper carried out research on temperature control methods of mass concrete for the purpose of ensuring construction quality based on the construction of Fengyi cable-stayed bridge caps. Firstly, the temperature and stress change rule in the concrete pouring process of the caps was analyzed though the finite element method (FEM). Then, targeted-oriented comprehensive temperature control schemes were formulated according to the structural characteristics and construction environment of the cap, including the optimization of the material ratio, the arrangement of crack-resistant reinforcing steel, the design of a water pipe cooling scheme and reasonable maintenance. Finally, the whole bridge cap construction process using the optimized water pipe cooling solution was monitored, and the temperature gap between inside and outside the concrete satisfied the specification requirements rigorously. In the concrete demolding session, the concrete surface was smooth and no cracks were found, which indicates the temperature control scheme is reasonable and effective. The research results have reference significance for the pouring and temperature control of mass concrete for bridge caps. [ABSTRACT FROM AUTHOR]

Gasoline fuel is a kind of fossil fuel that is still the primary fuel for vehicles and motorcycles nowadays. Demand for fuel continues to increase from time to time, so an effort is needed to save the use of fuel. This research is intended as an initial study to determine the quantity of heat energy converted and distributed into several engine performance parameters. Furthermore, the results of this study became the basis for the development of similar research to produce high engine performance and low emissions as well as economists by setting combustion parameters. The result shows that only a small portion of the heat generated from pertalite fuel is used as effective power. Most of the heat energy from the fuel is wasted in the environment and distributed into radiant heat, and some of it becomes heat to the exhaust gases and heat to the cooling water.

Copyright of Automobile Technology & Material is the property of Automobile Technology & Material Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Cooling water accounts for the majority of water usage in power plants. With the aggravation of water scarce all over the world, adaptive actions to optimize cooling system and improve water efficiency of cooling process are required. This review aims to provide a comprehensive insight of the issues involving water saving of cooling system for power plants. Limitation of current cooling technologies were firstly discussed. Then some retrofits and optimization of system designs that could significantly help to reduce water and energy consumption in power plant were presented. The possibity, complexities and challenges of some non-traditional water supplies such as reclaimed water and seawater recirculating cooling for power plant applications were introduced. The key technologies of water treatment and monitoring for water quality control were also illustrated and the water-saving effect brought by advanced technology was introduced. Finally, opportunities and challenges of management for cooling system were suggested.

Developing environmentally friendly and biodegradable corrosion inhibitors is an important research direction due to the toxicity and non-degradability of conventional carbon steel corrosion inhibitors added to circulating cooling water environments. Polysaccharides in EPSs (Exopolysaccharides) can be used as green corrosion inhibitors, but a low inhibition rate limits their practical application. Chemical modification is widely used to modify the functionality of polysaccharides by altering their physicochemical properties and structures, thereby enhancing or supplementing their functional characteristics. In this study, we employed chloroacetic acid as an esterifying agent to chemically modify Dextran and successfully synthesized a modified polysaccharide derivative with a substitution degree of 0.326. This derivative efficiently inhibited the corrosion of carbon steel in circulating cooling water environments. The carboxymethylated dextran (CM-Dextran) formed after synthesis could adsorb onto metal surfaces to form a protective film, thereby inhibiting metal surface dissolution reactions and exhibiting anodic corrosion inhibition properties. The experimental results showed that the corrosion inhibition efficiency of CM-Dextran after modification increased by up to 57.4%, with a maximum inhibition efficiency of 82.52% at a concentration of 4 mg/mL. This study provides new insights and opportunities for the development of environmentally friendly corrosion inhibitors derived from polysaccharides. [ABSTRACT FROM AUTHOR]

Changes in energy fuel markets, the rise of renewables and the aging of existing coal-fired units are leading to increased popularization of research on potential pathways for restructuring power systems. One proposed concept is the Coal-to-Nuclear path, which involves the partial use of existing coal-fired power plant infrastructure in favor of the construction of nuclear units, which can reduce investment costs. An additional benefit is the ability to manage the workforce competencies identified within the coal-fired power unit, and which are also required for the effective operation of the nuclear unit. The article considers the possibility of repowering the Kozienice power plant in Poland from the perspective of the availability of water used to cool the power units. Three different nuclear reactor technologies that are potentially being considered for the construction of the first nuclear units in Poland were analyzed. The study showed that the lowest water flows in the Vistula river recorded in 2022, equal to 146 m³/s, make it impossible to simultaneously cool the nuclear units and ensure sufficiently low water temperatures from an environmental perspective. Nuclear units were shown to require about 1.55-1.67 times more water for cooling than typical coal-fired units. [ABSTRACT FROM AUTHOR]

Copyright of Industrial Water Treatment is the property of CNOOC Tianjin Chemical Research & Design Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Muara Karang Power Plant (MKPP) is one of the main power plants on Java Island in Indonesia. Presently, the Jakarta provincial government has issued a reclamation project on Island G in the marine waters around MKPP. This reclamation effort is predicted to lead to a rise in the seawater temperature around the intake, which MKPP will address with the addition of intake channel of 250 - 957 m. Therefore, this study aimed to determine the effect of intake channel extension on the water temperature at the intake point using numerical modeling comprising hydrodynamics and dispersion advection modules. A total of 10 scenarios were modeled by varying intake channel length and season. The result showed that adding intake channel was less effective because the average water temperature was less than 0.24oC with an effectiveness below 0.78%. Based on the validation of the modeling results on the measurement data, the NRMSD values in west and east seasons were 9.13% and 12.63%, respectively. Under existing conditions, the average and maximum seawater temperatures were 31.40oC and 32.08oC. Meanwhile, by extending intake channel, the average and maximum water temperatures were 31.16oC and 31.60oC. These results showed that by extending intake channel, the temperature at the intake point was generally lower than the existing conditions. Intake channel length was more effective in reducing the temperature at the intake point during west monsoon than east monsoon. Vertically, the temperature at the bottom was relatively colder than near the surface. In west monsoon, the average temperature difference between the bottom and the surface ranged from 0.16-0.21oC, while in east, it was between 0.23 and 0.50oC. In conclusion, the addition of subsequent structures to increase effectiveness was necessary, specifically to hold hot water in east monsoon.

In the construction process of mass concrete structures, the large temperature gradient due to exothermic hydration makes the mass concrete highly susceptible to cracking. This paper carried out research on temperature control methods of mass concrete for the purpose of ensuring construction quality based on the construction of Fengyi cable-stayed bridge caps. Firstly, the temperature and stress change rule in the concrete pouring process of the caps was analyzed though the finite element method (FEM). Then, targeted-oriented comprehensive temperature control schemes were formulated according to the structural characteristics and construction environment of the cap, including the optimization of the material ratio, the arrangement of crack-resistant reinforcing steel, the design of a water pipe cooling scheme and reasonable maintenance. Finally, the whole bridge cap construction process using the optimized water pipe cooling solution was monitored, and the temperature gap between inside and outside the concrete satisfied the specification requirements rigorously. In the concrete demolding session, the concrete surface was smooth and no cracks were found, which indicates the temperature control scheme is reasonable and effective. The research results have reference significance for the pouring and temperature control of mass concrete for bridge caps.

In this study, the effect of hexamine, sodium nitrite, sodium benzoate, and trisodium phosphate corrosion inhibitors concentration on corrosion resistance of St37 carbon steel was studied (at 45 °C in closed-circuit cooling water) using weight loss, electrochemical impedance spectroscopy (EIS) and cyclic polarization tests. For hexamine and trisodium phosphate, with an increase in the concentration of the inhibitors, the corrosion rate decreased significantly. Therefore, the highest corrosion inhibition efficiency (IE%) of hexamine and trisodium phosphate was equal to 62% and 47% for concentrations of 400 ppm and 100 ppm, respectively. On the other hand, there was a critical concentration of sodium nitrite and sodium benzoate to protect carbon steel. For sodium nitrite and sodium benzoate, the highest IE% values were obtained at concentrations of 200 ppm and 5000 ppm, respectively, which were equal to 77% and 74%. According to the results, carbon steel was susceptible to pitting corrosion in the presence of different concentrations of the investigated inhibitors except sodium benzoate. The findings of EIS measurements were consistent with the results of polarization experiments. Overall, it was concluded that for the studied inhibitors, the corrosion control mechanism was charge transfer control in the electrical double layer. [ABSTRACT FROM AUTHOR]

Copyright of Tunnel Construction / Suidao Jianshe (Zhong-Yingwen Ban) is the property of Tunnel Construction Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The structures of water cooling systems are prone to microbially-influenced corrosion (MIC) due to the favorable conditions for microbial growth. Biofilm formation accelerates corrosion, leading to reduced system efficiency, structural damage, and significant financial losses. Encapsulating viable bacterial spores and biosurfactant within a silica-based sol-gel coating offers an eco-friendly approach to prevent this type of corrosion. Bacillus clausii, known for its antimicrobial biosurfactant production capability, was utilized in this study to investigate the impact of spores and biosurfactant addition to silica-based sol-gel coatings in inhibiting biofilm formation and preventing corrosion in water cooling systems. Microbiological analysis of the biofilm was conducted using the total plate count method, while the corrosion process was analyzed through electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The viability of B. clausii spores within the sol-gel matrix was determined to be 20.8 %. The presence of bacterial spores and biosurfactant significantly increased the hydrophobicity of the sol-gel coating. Incorporating spores within the sol-gel matrix delayed biofilm formation for up to 12 days, while biosurfactant addition showed the smallest biofilm abundance (2.23×105 CFU/mL) at its maturation phase compare to others. After 180 days of incubation, analysis of Bode and Tafel plots demonstrated that the sol-gel coating containing biosurfactant maintained excellent anti-corrosion performance, exhibiting an impedance of 104 Ω cm2, Ecorr of -0.398 V vs SCE, and icorr of 0.51 µA/cm2. SEM-EDS analysis of the surface sample revealed a comparably smooth and uniform surface with a minimal abundance of exposed Fe atoms at 0.12 %. In conclusion, this study demonstrated the high potency of the sol-gel coating supplemented with biosurfactant in inhibiting biofilm formation and corrosion on metals in water cooling systems.

This study quantitatively analysed the influence of cooling water parameters on the performance of a modular high-temperature gas-cooled reactor (MHTGR) nuclear power plant (NPP). The secondary circuit system and cold-end system were modelled using EBSILON software, version 16.0. The influence of cooling water inlet temperature and mass flow rate on the thermal performance of the secondary circuit system was analysed over the full power range with the goal of optimising net power. Under 100% rated condition, for each 1 °C increase in cooling water inlet temperature between 10 and 33 °C, the net power and cycle efficiency decreased by 0.67 MW and 0.14%, respectively, whereas the heat consumption rate increased by 28.72 kJ/(kW·h). The optimal cooling water mass flow rates corresponding to cooling water inlet temperatures of 16 °C and 33 °C were obtained. The optimal cooling water mass flow rate decreased nonlinearly with decreasing power levels. At a cooling water inlet temperature of 33 °C, an increase in cooling water mass flow rate from the designed value (7697.61 kg/s) to the optimal value (10,922.14 kg/s) resulted in a 1.03 MW increase in net power. These findings provide guidelines for MHTGR NPP operation optimisation and economic improvement, especially under high-temperature weather conditions. [ABSTRACT FROM AUTHOR]

The condenser needs to be cleaned so that the performance of the heat exchanger can optimally. This research was conducted on a water cooled chiller machine with a capacity of 650TR and the type of refrigerant used is R134a to determine the performance of the machine after cleaning process. The electric power used by the compressor’s motor before there was a fouling, fouling and after cleaning the condenser tubing were 174,80 kW, 191,22 kW and 174,42 kW respectively. The mass flow rate of cooling water before there is a fouling, fouling and after cleaning the condenser tubing is 98,01 kg/s, 106,74 kg/s and 126,15 kg/s respectively. The actual cooling load before there is a fouling, fouling and after cleaning the condenser tubing is 1352,46 kW, 1343,27 kW and 1363,92 kW respectively. Heat rejected before there is a fouling, fouling and after cleaning the condenser tubing is 1527,26 kW, 1534,49 kW and 1538,34 kW respectively. Coefficient of performance heating before there is a fouling, fouling and after cleaning the condenser tubing is 8,75, 8,04 and 8,82 respectively. Based on the results of the research, the performance of the water cooled chiller machine has increased after cleaning the condenser tubing.

Developing environmentally friendly and biodegradable corrosion inhibitors is an important research direction due to the toxicity and non-degradability of conventional carbon steel corrosion inhibitors added to circulating cooling water environments. Polysaccharides in EPSs (Exopolysaccharides) can be used as green corrosion inhibitors, but a low inhibition rate limits their practical application. Chemical modification is widely used to modify the functionality of polysaccharides by altering their physicochemical properties and structures, thereby enhancing or supplementing their functional characteristics. In this study, we employed chloroacetic acid as an esterifying agent to chemically modify Dextran and successfully synthesized a modified polysaccharide derivative with a substitution degree of 0.326. This derivative efficiently inhibited the corrosion of carbon steel in circulating cooling water environments. The carboxymethylated dextran (CM-Dextran) formed after synthesis could adsorb onto metal surfaces to form a protective film, thereby inhibiting metal surface dissolution reactions and exhibiting anodic corrosion inhibition properties. The experimental results showed that the corrosion inhibition efficiency of CM-Dextran after modification increased by up to 57.4%, with a maximum inhibition efficiency of 82.52% at a concentration of 4 mg/mL. This study provides new insights and opportunities for the development of environmentally friendly corrosion inhibitors derived from polysaccharides.

Organic Rankine cycle (ORC) uses low-temperature heat source to realize thermoelectric conversion, which is an important way to realize the effective recovery and utilization of waste heat. Based on the horizontal tube spray falling film evaporator, an orc power generation system with R245fa as the circulating working medium is built to study the influence of the change of cooling water flow on the heat transfer performance of the evaporator. The results show that under the condition of constant heat source temperature, the evaporation pressure and condensation pressure first decrease and then increase with the increase of cooling water flow, while the total heat transfer coefficient outside the evaporator tube first increases and then decreases. When the cooling water flow is greater than 3100 L/h, it has little effect on the heat exchange system of the evaporator, and it is more appropriate to keep the cooling water flow at about 3100 L/h. By studying the influence of cooling water flow on the heat transfer performance of evaporator, an important experimental basis is provided for the design and optimization of ORC cooling system.

Copyright of Tobacco Science & Technology is the property of Tobacco Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Sustainable development requires a holistic approach to natural resources and ecosystems to avoid their degradation. Cooling water—water used for cooling in industrial or manufacturing processes and then returned at elevated temperature to a local river or lake—is a common cause of thermal pollution. The purpose of the analysis was to assess how much cooling water is currently abstracted to generate electricity in Poland, what the dynamics of this abstraction in the last 20 years (2000–2019) were, and to what extent this abstraction affects the available freshwater resources in the country and in individual river basins. Moreover, the latest plans for the development of the electricity sector in Poland were analyzed to determine how the implementation of these plans may affect cooling water abstractions and the condition of Poland's freshwater resources. Trend analysis was performed in order to assess the strength of linear trends in the studied time series. The results show that in Poland from 2000–2019, nearly 75% of water abstracted from surface resources was cooling water used to produce electricity. The dynamics of cooling water abstraction show a clear downward trend of 54.5 million m3 annually, despite a significant increase in electricity production. This decline is likely to continue over the next 20 years, with the major unknown being the planned introduction of nuclear power as an energy source. [ABSTRACT FROM AUTHOR]

The method of anti-scale stabilization treatment of cooling water of the circulating cooling system (CCS) with sulphuric acid to reduce the content of bicarbonate and carbonate ions allows to effectively reduce scale formation processes in power plant’s cooling systems. The results of the research and analysis of the sulphuric acid dosage to ensure the water-chemical regime of the reversible cooling system are presented in the example of the Rivne NPP. The analysis of the results of the control of the technology of stabilization treatment of cooling water with sulphuric acid was carried out, as the influence of the technological changes on the content of sulfate ions in the discharge water and the influence of the water discharge into a water body were evaluated. The sulphuric acid stabilization treatment makes it possible to neutralize the alkalinity caused by the content of bicarbonate and carbonate ions and to convert the proportion of calcium ions bound to bicarbonate and carbonate ions into a permanent hardness that is not prone to scale formation under the influence of temperature and has a lower tendency to scale formation. The use of sulphuric acid may be suitable for the optimal choice of water chemistry regime for scale reduction in CCS, according to the criteria of acidification of additional cooling water, which is the dosing criterion. The technological regimes for CCS stabilization treatment with sulphuric acid introduced at the Rivne Nuclear Power Plant (NPP) ensured a decrease in the use of sulphuric acid and a decrease in discharges into the water body by an average of 220 t/year, a decrease in the increase in the content of sulfate ions before the water intake and after the water discharge of the Rivne NPP, which correlates with a decrease in the amount of sulphuric acid used for CCS water treatment and a decrease in the environmental impact on the water bodies of the Styr River.

The article presents a comparison of the real overall heat transfer coefficient, based on thermal tests of the condenser of the steam turbine PT-25-90 KTZ during off-design operation (with a degraded vacuum) and its expected value, calculated via the Metropolitan Vickers formula. The average cooling water inlet temperature was 61.2 °C, average exhaust steam pressure was 0.542 bar during thermal tests. The average deviation of the expected overall condenser heat transfer coefficient from the real value was 27,18%. The calculations showed a higher difference between the real and expected value at the regimes with low cooling water velocity and with high exhaust stem pressure. The obtained results showed the need to refine the methodology of the condenser's overall heat transfer coefficient calculation in the degraded vacuum mode. This can be done by adding correction factors to the water temperatures that are typical for the degraded vacuum regime.

In order to explore the corrosion behavior of the surface of carbon steel equipment substrate caused by the cooling water in hydropower plants, corrosion coupon method, surface analysis and electrochemical measurement technology were used to study the corrosion laws and corrosion mechanisms of Q235 carbon steel sheets immersed in cooling water of hydropower plants. Results showed that the Mg2+ and Ca2+ in the cooling water accelerated the corrosion process of carbon steel. The kinetic simulation calculation was used to study the factors inducing the reaction and it was found that with the presence of Mg2+ and Ca2+, the mean square displacement and the diffusion coefficient of the corrosion product film both increased to a certain extent, and the corrosion ions were adsorbed by means of forming chemical bonds with the corrosion product film surface, thus obtaining a large adsorption energy. So it was concluded that the increase of Cl- content would aggravate the corrosion of carbon steel equipment in hydropower plants, and the coexistence of Cl, Mg, and Ca elements in cooling water was the reason for the increasing corrosion rate of carbon steel equipment.

Considering the waste of fresh water in a 256 MW steam power plant located in the southeast of Iran, and to compensate a part of its water consumption, a humidification-dehumidification (HD) desalination system is proposed. Because of sedimentation problems in indirect-contact HD systems, in this research, the application of direct-contact HD method to recover the effluent stream in a steam power plant is presented. Considering unit cross-sectional area for HD towers and based on primary results of the modeling, up to 119 lit/hr can be produced when the height of both humidifier and dehumidifier is 1.8 m and the flow rate of air is 0.7 kg/s. Three different scenarios based on (I) full capacity of available steam from the blowdown of boilers, (II) available chemical effluent (salt water), and (III) available cooling water, are examined and compared in this research. As, required salt water or/and cooling water are much more than the available amounts in the power plant, scenario I and II are rejected. Based on obtained resulted from the scenario III, the cost of production is 0.8 $/m3 of fresh water, and the GOR of proposed HD desalination unit is 1.03. With consumption of less than 5% and 10% of the available steam and salt water in the power plant, respectively, more than 7.5 m3/day of fresh water can be produced by the proposed direct-contact HD desalination system.

The South China Sea has huge reserves of thermal energy resources and suitable water depth and seabed topography. It is an ideal place for exploring ocean thermal energy. To analyze the impact of cooling water discharge on the environment of the sea near Ganquan Island where an ocean thermal power station is planned in Xisha Archipelago, the South China Sea, a three-dimensional hydrodynamic model was established by using a numerical simulation method and the reliability of the model was verified against the measurement date of tide level at the Yongxing Island tide survey station. The diffusion process of cooling water around the power plant and its influence on water temperature structure in nearby waters were simulated and analyzed. Results show that the cooling water from the power station generates a sharp drop in temperature around the outfall, and then a thermocline is formed locally. However, the temperature drop is mainly concentrated near the outfall and spreads with the tidal flow. The temperature gradient at the outfall is the largest, and the temperature gradient tends to be smaller away from the outfall. The envelope area of the thermocline decreases with the increase of the drainage temperature and increases with the increase of the drainage flow. There is a thermocline above the cold water mass and an inverse one below, and the upper boundary depth of the thermocline increases with the increase of drainage depth. This research assesses the environmental issues involved in the construction of the ocean thermal power stations and provides a scientific basis for the management of the ecological environment. [ABSTRACT FROM AUTHOR]

In this study, the corrosion behavior of Q235 carbon steel (CS) under a Bacillus cereus (B. cereus) inoculum in simulated cooling water was evaluated. The weight loss study proved B. cereus inoculum possessed anticorrosion efficiencies of 92.84% and 73.88% for 3-day and 14-day rotation tests, respectively. The electrochemical measurements indicated that the added B. cereus inoculum increased the charge transfer resistance and reduced corrosion current density. B. cereus cells with strong biofilm-forming capacity were able to adhere onto the Q235 CS surface to form compact biofilms and cause biomineralization. Surface characterization analysis demonstrated that the presence of the B. cereus inoculum reduced the amount of Fe2O3 and simultaneously increased the amount of CaCO3 in corrosion products. The corrosion inhibition mechanisms of the B. cereus inoculum involve forming biofilm, generating a biomineralized layer, and consuming dissolved oxygen. Thus, B. cereus inoculum provides a biological strategy for industrial cooling water anticorrosion application. [ABSTRACT FROM AUTHOR]

In this study, six strains of microbial agents were investigated as environmently friendly scale and corrosion inhibitors for industrial cooling water applications. The static jar tests along with characterization methods were applied to evaluate the scale inhibition performance. Results showed that under a concentration of 240 mg/L, the nitrobacteria, denitrobacteria and Lactobacillus agents reached high CaCO3 scale inhibition efficiencies of 83, 82, and 86% respectively. Characterization methods indicated the deposited crystals morphologies were modified and the crystals peak intensities were lowered. In addition, weight loss measurements, electrochemical measurements, surface characterization analyses were conducted to study the corrosion inhibition performances and mechanisms. It was found that at 40 °C, Bacillus cereus agent with 200 mg/L possessed the highest corrosion inhibition efficiency of 60.11% at 3 d, together with the second-lowest current density of 13.0 μA cm−2 at 12 d. The corrosion inhibition mechanisms were attributed to biofilm accumulation and biomineralization on Q235 CS surfaces to form protective film. The results suggested microbial agents have promising potential as environmently friendly scale and corrosion inhibitors for industrial cooling water applications. HIGHLIGHTS The feasibility of microbial agents using as scale and corrosion inhibitors was confirmed.; The CaCO3 scale inhibition efficiency of Lactobacillus agent after 24 h activation reached 87.60%.; Bacillus cereus agent displayed superior corrosion inhibition performance with a first accelerated, then inhibited, finally accelerated corrosion process.; The scale and corrosion inhibition effect closely related to microbial metabolism.;

This study quantitatively analysed the influence of cooling water parameters on the performance of a modular high-temperature gas-cooled reactor (MHTGR) nuclear power plant (NPP). The secondary circuit system and cold-end system were modelled using EBSILON software, version 16.0. The influence of cooling water inlet temperature and mass flow rate on the thermal performance of the secondary circuit system was analysed over the full power range with the goal of optimising net power. Under 100% rated condition, for each 1 °C increase in cooling water inlet temperature between 10 and 33 °C, the net power and cycle efficiency decreased by 0.67 MW and 0.14%, respectively, whereas the heat consumption rate increased by 28.72 kJ/(kW·h). The optimal cooling water mass flow rates corresponding to cooling water inlet temperatures of 16 °C and 33 °C were obtained. The optimal cooling water mass flow rate decreased nonlinearly with decreasing power levels. At a cooling water inlet temperature of 33 °C, an increase in cooling water mass flow rate from the designed value (7697.61 kg/s) to the optimal value (10,922.14 kg/s) resulted in a 1.03 MW increase in net power. These findings provide guidelines for MHTGR NPP operation optimisation and economic improvement, especially under high-temperature weather conditions.

Using less water to generate more power is a goal of the worldwide power industry, but this is difficult to achieve because of the lack of long-term, operational data-based studies. This challenge is especially severe for megacities facing water shortages. This study used long-term data (2005–2015) from Shenzhen, a megacity of over 20 million people that faces severe water shortages, to determine the relationship between water and energy for different types of power generation. It was found that power generation consumed huge amounts of water and that cooling water was the biggest water use category. Smaller power plants, such as the Yueliangwan power plant, which uses the closed cooling method, consume 2.36 million m3 of tap water per year, equivalent to the water supply of a small reservoir. However, larger power plants, such as the Mawan power plant and Dayawan nuclear power plant (using the open cooling method), use 0.92 and 3.42 billion m3 of seawater for cooling every year, respectively, equivalent to about 60% and 200% of the total annual water supply in Shenzhen, respectively. Therefore, large thermal power plants and nuclear power plants should be built in coastal areas with rich water resources rather than in arid or semi-arid areas. Additionally, the water use efficiency of nuclear power plants was found to be 0.22 m3/kWh, which was significantly lower than that of coal-fired power plants (0.10 m3/kWh) and gas-fired power plants (0.09 m3/kWh). Third, the water use efficiency of the closed cooling method was ten times higher than that of the open cooling method. Therefore, the closed cooling method is suitable for power plants constructed in areas without rich water resources. These results are useful for balancing the water and energy demands in the changing world. [ABSTRACT FROM AUTHOR]

The sea is generally adopted as the ultimate heat sink for coastal nuclear power plants. Multiple protection measures have been taken to prevent the invasion of foreign matters, thus ensuring the safety of water intake. However, the production practice shows that some marine organisms and sundries can break those protection measures and threat the safe and stable operation of nuclear power units. The installation of trash-intercepting net is an effective means to reduce the risk of cooling water intake safety. Based on the engineering practice of trash -intercepting nets of water intake projects in several domestic coastal nuclear power plants, the functional requirements and orientations and design principles have been analyzed, studied and determined from the perspective of engineering design. Moreover, a standard '3+n' design scheme has been proposed, and relevant design points have been discussed in detail. [ABSTRACT FROM AUTHOR]

In this study, a natural gas purification plant adopts open circulating water system, which cannot work properly and hinder the normal production of natural gas due to the problems such as scaling and blockage in the operation of heat exchanger device was reported. Qualities of the make‐up water and recirculating cooling water were evaluated by parameters such as hardness, alkalinity, pH, and conductivity. X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), and optical microscope were employed to study the crystal structure, composition, and morphology of the scale deposits. The flow rate of the water in the tube bundle was calculated according to the design scale of these exchangers. The Langelier Saturation Index (LSI) was used to analyze the scale tendency of the cooling water system. The scale inhibition performance of the inhibitor was verified by static inhibition method. Results show that the scale mainly contains calcium carbonate, and the quality of circulating water is reasonably controlled with a proper range. However, there are three units sharing one cooling water system, of which the flow rate cannot be adjusted according to the actual heat load. The calculation results confirmed that the circulating water velocity in the tube bundle did not exceed 0.9 m/s. Although the scale inhibitor has a scale inhibition efficiency of more than 90% for the simulated circulating water at 80°C, the LSI analysis results showed that the high local temperature on the surface of the tube bundle caused by the low flow rate of water will increase the scaling tendency of the heat exchanger. Furthermore, the untimely injection of the inhibitor in the daily management and operation also greatly increased the risk of system scaling. This paper proves that the scaling of circulating water heat exchanger in the purification plant is mainly caused by device design and poor daily management. In order to prevent future failures, potential solutions and mitigation strategies were put forward. [ABSTRACT FROM AUTHOR]

Microplastic (MP), an emerging pollutant, has been identified as a critical target in tackling plastic pollution. Although a plethora of studies have explored MP generation from various sources, limited attention has been paid to plastic processing. This study investigated MP (10 μm-5 mm) generation in virgin and waste plastic extrusion processing. MPs at a density of 2.13 × 10 5 -9.79 × 10 7 (approximately 0.01-10.85 g) were generated when processing 1 t of plastic. Feedstock sources, polymer types, and pelletizing techniques were found to influence the process. With a moderate weight (270.58-527.34 t) but enormous amount (1.34 × 10 16 -2.63 × 10 16 ) of MPs generated globally in 2022, plastic processing is an underestimated but vital source of MPs, emphasizing the need for MP inspection and appropriate removal technologies in the industry, especially for virgin plastic processing and water ring pelletizing. Further simulation indicated that up to 84.35% of MPs could be removed using commonly available materials in the investigated plastic processing facility, with a higher removal efficiency for larger-sized particles. In this regard, plastic recycling was superior to virgin plastic processing with fewer and larger-sized MPs generated, which could facilitate MP removal and should be fostered.

The SORGENTINA-RF project aims at developing a 14 MeV fusion neutron source featuring an emission rate in the order of 5–7 × 10 13 s − 1 . The plant relies on a metallic water-cooled rotating target and a deuterium (50%) and tritium (50%) ion beam. Beyond the main focus of medical radioisotope production, the source may represent a multi-purpose neutron facility by implementing a series of neutron-based techniques. Among the different engineering and technological issues to be addressed, the production of incondensable gases and corrosion product into the rotating target deserves a dedicated investigation. In this study, a preliminary analysis is carried out, considering the general layout of the target and the present choice of the target material. [ABSTRACT FROM AUTHOR]

The detection and enumeration of Legionella pneumophila (L. pneumophila) in water is crucial for water quality management, human health and has been a research hotspot worldwide. Due to the time-consuming and complicated operation of the plate culture method, it is necessary to adopt a fast and effective method for application. The present study aimed to comprehensively evaluate the performance and applicability of the MPN method by comparing its qualitative and quantitative results with the GB/T 18204.5-2013 and ISO methods, respectively. The qualitative results showed that 372 samples (53%) were negative for both methods; 315 samples (45%) were positively determined by the MPN method, compared with 211 samples (30%) using GB/T 18204.5-2013. The difference in the detection rate between the two methods was statistically significant. In addition, the quantitative results showed that the concentration of L. pneumophila by the MPN method was greater than ISO 11731 and the difference was statistically significant. However, the two methods were different but highly correlated (r = 0.965, p < 0.001). The specificity and sensitivity of the MPN method were 89.85% and 95.73%, respectively. Overall, the results demonstrated that the MPN method has higher sensitivity, a simple operation process and good application prospects in the routine monitoring of L. pneumophila from water samples. [ABSTRACT FROM AUTHOR]

Utilizing the thermal stratification of reservoirs to obtain cold water for cooling green data centers (GDCs) is a new mode of energy conservation and emission reduction. However, global warming is expected to alter this phenomenon in deep reservoirs and thus may affect the digitalization process. While the frequency and intensity of extreme climate (EC) events are increasing under a changing climate, the impacts of these highly destructive events on thermal stratification and the related cascading effects on GDC cold-water supplies are still unclear. A two-lateral-dimensional thermohydrodynamic model was established to determine the characteristics of reservoir thermal stratification changes and its potential water environment impacts based on the heat extreme experienced by the Jinshuitan Reservoir, a large, pumped storage power station (PSPS) with a GDC in southeastern China. Fourteen different PSPS inlet/outlet schemes under 2 climate scenarios were designed, and two new indexes, namely, the risk index of cold-water shortage and the index of thermal stratification, were proposed to explore the impact of extreme climates on GDC water extraction. The results showed that compared to the present climate conditions, the reservoir experienced stronger thermal stratification with a 20.6 % average increase in thermal stability, a longer thermal stratification duration with a transitional trend from seasonal to permanent stratification, and a thinner cold-water layer with a 15-m average decrease. Changes in the thermal stratification of reservoirs under EC conditions will benefit some species, such as diatoms (except for early July and the period from mid-August to early October), green algae and cyanobacteria and the migration of warm-water fish, but adversely impact dissolved oxygen, diatoms and cold-water fish. Furthermore, the risk of cold-water shortages under EC conditions was consistently greater than that under average climate (AC) conditions (traditional assessment) when the elevation of pumped storage intake/outlet was less than 145 m. According to the traditional assessment method, the intake/outlet elevation of pumped storage reservoirs resulted in a 60.27 % increase in the risk of cold-water shortages during climate extremes. Furthermore, the demand for green cold-water withdrawal and optimal pumped storage power generation benefits were met when the PSPS intake/outlet elevation was 145 m. Beyond solving this specific case, this study elucidates the importance of linking the thermal stratification and data center of cold-water withdrawal to ECs. These findings provide new insights for increasing climate change resilience. [Display omitted] [ABSTRACT FROM AUTHOR]

Sustainable development requires a holistic approach to natural resources and ecosystems to avoid their degradation. Cooling water—water used for cooling in industrial or manufacturing processes and then returned at elevated temperature to a local river or lake—is a common cause of thermal pollution. The purpose of the analysis was to assess how much cooling water is currently abstracted to generate electricity in Poland, what the dynamics of this abstraction in the last 20 years (2000–2019) were, and to what extent this abstraction affects the available freshwater resources in the country and in individual river basins. Moreover, the latest plans for the development of the electricity sector in Poland were analyzed to determine how the implementation of these plans may affect cooling water abstractions and the condition of Poland’s freshwater resources. Trend analysis was performed in order to assess the strength of linear trends in the studied time series. The results show that in Poland from 2000–2019, nearly 75% of water abstracted from surface resources was cooling water used to produce electricity. The dynamics of cooling water abstraction show a clear downward trend of 54.5 million m3 annually, despite a significant increase in electricity production. This decline is likely to continue over the next 20 years, with the major unknown being the planned introduction of nuclear power as an energy source.

An advanced cogeneration system based on biomass direct combustion was developed and its feasibility was demonstrated. In place of the traditional single heat source (extraction steam), the extraction steam from the turbine, the cooling water from the plant condenser, and the low-pressure feedwater from the feedwater preheating system were collectively used for producing district heat in the new scheme. Hence, a remarkable energy-saving effect could be achieved, improving the overall efficiency of the cogeneration system. The thermodynamic and economic performance of the novel system was examined when taking a 35 MW biomass-fired cogeneration unit for case study. Once the biomass feed rate and net thermal production remain constant, an increment of 1.36 MW can be expected in the net electric production, because of the recommended upgrading. Consequently, the total system efficiency and effective electrical efficiency augmented by 1.23 and 1.50 percentage points. The inherent mechanism of performance enhancement was investigated from the energy and exergy aspects. The economic study indicates that the dynamic payback period of the retrofitting project is merely 1.20 years, with a net present value of 5796.0 k$. In conclusion, the proposed concept is validated to be advantageous and profitable. [ABSTRACT FROM AUTHOR]

Summary: In large thermal power facilities, thermal machines mainly fitted with steam turbines are used in thermodynamic process of converting thermal energy into mechanical work. In order to improve the efficiency of heat energy conversion into mechanical work, the increase of vacuum level in the condenser of a steam turbine was analyzed using the machine learning method. The vacuum in the steam turbine condenser increases after replacing the labyrinth gaskets with honeycomb ones, resealing the vacuum system and increasing the amount of cooling water through the condenser. The latter is controlled by algorithm, which is integrated into the steam turbine distribution control system. As a result of the increased vacuum in the steam turbine condenser, the enthalpy difference of the steam turbine low‐pressure cylinder increases, and the steam turbine performs more mechanical work resulting in higher conversion efficiency. The drawback of the increased vacuum in the turbine condenser is that the flow of cooling water through the steam turbine condenser increases as well as heat dissipation from the condenser into the environment to be replaced by regenerative condensate heating. The results of the analysis show that the overall balance of the vacuum increase in the steam turbine condenser is positive, the steam turbine generates more power, and consequently the process efficiency increases by as much as 2.48 %. [ABSTRACT FROM AUTHOR]

This paper presents the influence of cooling water regulation on power plant net efficiency. It was examined whether, for the non-nominal low-pressure turbine load, it is justified to reduce the cooling water pump load, and how it would affect the unit net efficiency. Calculations for two types of power units were carried out: with condensing and extractioncondensing turbine. The tested condensing power plant consists of three surface condensers. The calculation included four condensers' connections set up on the cooling water side to check how the cooling water system pressure drop affects the net unit performance. The result has confirmed that implementing serial connection decreases net efficiency when cooling water flow regulation is used, but the mixed connection should be applied when pump load is not controlled. It was proved that the cooling water flow control gives a profit for both units. Net efficiency for combined heat and power plant can be improved by 0.1-0.5 pp, the gain is remarkable below 60% of the low-pressure turbine part load. Flow control implementation in the unit with condensing turbine water control gives a similar profit just below 80% of the turbine load. Next, an influence of the additional limitations of a cooling water system (minimal total pump head, cooling tower) affecting the feasibility of implementing the water control has been considered. Applying a multi-cell forced draft cooling tower does not have a significant impact on results, but when a natural draft cooling tower is used, the flow control range is strongly reduced. [ABSTRACT FROM AUTHOR]

Cooling water of Heavy Ion Research Facility in Lanzhou is the media of choice for absorbing heat generated by a multitude of accelerator components. During the operation, tritium is produced by the secondary neutrons in the accelerator loop of accelerator cooling water, which is uniformly distributed in the water system in the form of hydrogen tritium oxide. The purpose of this study is to establish a rigorous method to measure the low levels of tritium in the accelerator cooling water system. The cooling water samples of Sector Focusing Cyclotron and Separated Sector Cyclotron of Heavy Ion Research Facility in Lanzhou, as well as the natural levels of tritium, were measured successfully, using Quantulus1220 ultra-low-level background liquid scintillation spectrometer. The electrolytic enrichment method was employed to measure the tritium activity concentrations of the cooling water samples. Moreover, the minimum detectable activity concentration and the counting rate efficiency curve of the liquid scintillation spectrometer were obtained to ensure reliability. In this work, we provide a reference to establish the related standards and specifications for monitoring the tritium levels in heavy-ion accelerator cooling water system.

Failure and loss in hydrocarbon storage tanks lead to severe environmental and economic losses, reach hundreds of millions of dollars, as well as human casualties. These losses are magnified due to fire propagation between tanks caused by intense incident radiation on adjacent tanks that are exposed to the fire. Codes and standards recommendations regarding spacing between tanks and cooling water application rate are inconsistent and contradicting. According to the author review, scarce studies investigated circular pool fires and the accompanied thermal radiation on cylindrical surfaces on Fire Dynamics Simulator (FDS). This study numerically investigates the thermal radiation emitted from full surface circular pool fires on the adjacent cylindrical tanks surfaces on FDS. Additionally, the study analyzes the effect of different parameters such as fuel type, wind effect and spacing between tanks on fire propagation in hydrocarbon storage tanks. In addition, the effect of the cooling water application rate and its variation with the above parameters on prevention of fire propagation is investigated. The incident heat flux produced from using Heptane fuel was from 30 to 77% higher than that produced from using ethanol fuel. Increasing wind speed from zero to 3 m/s caused the incident heat flux to increase up to four times the initial value. Increasing the spacing between tanks from 0.5 to one time, the pool fire diameter caused more than 30% reduction in the incident heat flux on the target tank. Application of cooling water on the surface of the tanks exposed to fire showed significant reduction in incident heat flux while applying 2 Lit/min × m2 of cooling water, this reduction reached 50% in some cases. However, doubling the cooling water application rate to 4 Lit/min × m2 showed limited improvement in cooling rate, ranged between 5 and 15%. These findings are consistent with IP19 standard recommendations against other codes and standards. [ABSTRACT FROM AUTHOR]

Copper tubes are used in refrigerator and air conditioning unit heat exchangers. However, in some cases, the areas in copper tubes subjected to mechanical processing experience pitting corrosion. Therefore, a test scheme to rapidly evaluate the corrosion resistance of copper tubes in these sections and the effectiveness of the initial treatment on corrosion resistance were investigated. The initial treatment is a chemical treatment that improves the corrosion resistance of copper tubes. The corrosion of copper tubes was investigated by observing the surface after immersing the copper tube in various solutions containing hydrogen peroxide, chloride ions, sulfate ions, benzotriazole and hydrogen carbonate ions for one day. The test solution that contained a combination of 10 mg/L hydrogen peroxide (H2O2), 300mg/L chloride ions (Cl-), 300mg/L sulfate ions (SO42-) and 10 mg/L benzotriazole was found to replicate actual corrosion processes on the copper tubes over 1 day. The results indicated a high tendency for corrosion to occur in the mechanically processed sections. The improved corrosion resistance in these sections from the initial treatment was also confirmed in the test solution. Additionally, the corrosion resistance in the mechanically processed sections of copper tubes was weaker as the residual carbon amount increased. [ABSTRACT FROM AUTHOR]

Using less water to generate more power is a goal of the worldwide power industry, but this is difficult to achieve because of the lack of long-term, operational data-based studies. This challenge is especially severe for megacities facing water shortages. This study used long-term data (2005–2015) from Shenzhen, a megacity of over 20 million people that faces severe water shortages, to determine the relationship between water and energy for different types of power generation. It was found that power generation consumed huge amounts of water and that cooling water was the biggest water use category. Smaller power plants, such as the Yueliangwan power plant, which uses the closed cooling method, consume 2.36 million m3 of tap water per year, equivalent to the water supply of a small reservoir. However, larger power plants, such as the Mawan power plant and Dayawan nuclear power plant (using the open cooling method), use 0.92 and 3.42 billion m3 of seawater for cooling every year, respectively, equivalent to about 60% and 200% of the total annual water supply in Shenzhen, respectively. Therefore, large thermal power plants and nuclear power plants should be built in coastal areas with rich water resources rather than in arid or semi-arid areas. Additionally, the water use efficiency of nuclear power plants was found to be 0.22 m3/kWh, which was significantly lower than that of coal-fired power plants (0.10 m3/kWh) and gas-fired power plants (0.09 m3/kWh). Third, the water use efficiency of the closed cooling method was ten times higher than that of the open cooling method. Therefore, the closed cooling method is suitable for power plants constructed in areas without rich water resources. These results are useful for balancing the water and energy demands in the changing world.