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There is a certain deviation between the calculated daily water loss and the actual water loss in the circulating water system of a certain refinery. Regarding this issue, the calculation of water loss in the circulating water system has been corrected. By comparing the water loss data of the experimental device with the calculated data and using the least squares method for fitting, the deviation rate between the actual loss amount and the calculated value can be controlled within 5% when the optimal interval change slope k of the fitted curve L is controlled between 1.06 -1.09 and the optimal interval change intercept b of the circulating water is controlled between 14 and 19. When k is set to 1.07 and b is set to 15, the maximum deviation rate is only 4.77%, which verifies the feasibility of the algorithm. [ABSTRACT FROM AUTHOR]

The article presents the results of laboratory testing to select the optimal flocculant for clarification of circulating water from the shaft furnace gas cleaning of the metallization department. Laboratory testing was carried out using the standard settling (clarification) technique in sedimentation glasses. It is shown that the use of a liquid emulsion flocculant with a low cationic charge and high molecular weight allows for the successful removal of suspended and colloidal substances from the circulating water of the gas cleaning system and ensures the quality of the clarified water corresponding to the standard for the content of suspended substances ≤30 mg/dm3. It is established that the optimal dosing point for the selected liquid emulsion flocculant is a zone of high turbulence and intensive mixing, i.e., the receiving chamber of the radial-flow settling tank. The proposed reagent treatment program is recommended for industrial use for clarification of shaft furnace gas cleaning circulating water of one of the metallurgical plants in Russia. The optimal dosage range of the selected cationic flocculant (according to the commercial reagent) based on the wastewater entering the radial-flow settling tank is 0.4–0.5 g/m3. [ABSTRACT FROM AUTHOR]

A hybrid cooling tower, which is a promising type of coolers, can be used successfully to cool the circulating water of industrial enterprises taking into account the modern requirements for energy efficiency, resource saving, and environmental friendliness. A hybrid cooling tower design has been developed including a sprinkler made of inclined corrugated contact elements and an internal finned tubular radiator. The purpose of the work is to experimentally determine the volumetric coefficients of heat and mass emission in the developed hybrid cooling tower for cooling circulating water. A diagram of an experimental installation of a cooling tower with hybrid cooling system is presented and described. Graphic dependences were constructed for the volumetric coefficients of mass emission and heat emission on the average flow rate of cooling air at various wetting mass densities. A dimensionless equation has been obtained for determining the volumetric coefficients of mass emission in a hybrid cooling tower with transverse finning of radiator pipes. A comparison of volumetric coefficients of mass emission for the developed cooling tower with other water-cooling devices showed the potential of its usage for cooling circulating water, especially at high ratios of gas and liquid phase loads. [ABSTRACT FROM AUTHOR]

Objective PESA and terpolymer were used as the primary raw materials for formulation screening in the research and development process of phosphorus-free corrosion and scale inhibitors. Methods The adaptability of phosphorus-free corrosion and scale inhibitors were evaluated and studied through the corrosion test and static scale inhibition tests. Results It was further applied to the circulating water system of a natural gas purification plant in Sichuan and Chongqing. Through field monitoring, the non-phosphorus corrosion and scale inhibitor achieved good corrosion and scale inhibition effect, and the corrosion rate was controlled below 0.075 mm/a. Meanwhile, the bacteria numbers in circulating water were counted before and after the test. The results showed a trend of continuous decrease, and the eutrophication degree of water was reduced, indicating that the phosphorus-free formula had a positive effect on the bacterial control of the system. Conclusion The laboratory study and field test results confirm that the screened corrosion and scale inhibitor system has excellent effect in water with medium and low levels of hardness and can guarantee the stable operation of the circulating water system in natural gas purification plant. [ABSTRACT FROM AUTHOR]

In this paper, a comparative analysis of the parameters of water steam condensation was performed in the calculations of the built-in bundle of the condenser of a cogeneration steam turbine using the Metro-Vickers method and the refined method of the All-Russian Thermal Engineering Institute. A computational analysis of the operating modes of the condenser was also performed using various calculation methods with the joint cooling of the main bundles of the condenser with circulating water, as well as that of the built-in bundles with raw water with a wide variation of the main parameters. The results established that the values of the heat transfer coefficients for the built-in bundle, determined using various methods, differed significantly from each other, especially at low values of the specific heat load of the condenser, limiting the use of the Metro-Vickers method under these conditions. In the calculation analysis of the condenser operating modes, several dependencies obtained using the Metro-Vickers method demonstrated significantly greater differences from the experimental data than when using the refined method of the All-Russian Thermal Engineering Institute, especially at reduced condenser steam loads. The study also identified several features of the joint operation of the main and built-in condenser bundles in the cogeneration modes of the turbine unit. [ABSTRACT FROM AUTHOR]

The scaling problem exists universally in circulating water systems. Efficient and accurate assessment of scaling tendency is a prerequisite for solving the problem. In this work, it proposes electrolysis to induce hardness variation, which connects with the water stability evaluation index for quantitatively assessing the scaling tendency of water. The quantitative assessment is further realized on the basis of qualitative assessment. Then, the dynamic simulation experiments of circulating water are carried out to provide support for the electrolysis-induced hardness variation which clarifies the criteria that can meet the actual water requirements. This work can achieve an efficient and accurate quantitative assessment of the scaling tendency, which is of great significance for solving the scaling problem of circulating water systems. HIGHLIGHTS An electrolysis method is proposed to induce hardness variation of water.; Relationship is built between hardness variation and evaluation index.; Hardness variation is used to assess the scaling tendency quantitatively.; Dynamic simulation experiments support the availability of assessed results.;

Mathematical models of the dependence of the critical pitting temperature (CPT) of AISI 304, AISI 321, 12Kh18N10T and 08Kh18N10 steels on their chemical composition, structural heterogeneity, as well as pH and chloride concentration of circulating water were developed. Models were based on quadratic regressions with first order partial derivatives and on polynomials with a reduced number of signs. By applying mathematical models, it was established that the pitting resistance of these steels increases with an increase in the average distance between oxides, the average diameter of austenite grain, specific magnetic susceptibility, the decrease in the volume of δ-ferrite and the number of the smallest oxides up to 1.98 μm in size. The positive effect of Cr and Mn on the pitting resistance of the studied steels was studied. Probably this occurred due to the increase of the solubility of N in austenite, reduction of the Fe atoms diffusion intensity to the surface of stable pittings and the increase of Cr to metastable pittings, contributing to their repassivation, which increased the pitting resistance of steels. The developed mathematical models are recommended for choosing optimal grades of austenitic steels and predicting their pitting resistance during operation of heat exchangers in circulating waters. [ABSTRACT FROM AUTHOR]

The closed circulating water system of a power plant generally adopts the operation mode of an expanded unit system. When the output of circulating water pumps of parallel units is different， there will be channeling flow. Under such circumstances， the circulating water flow entering the condenser is not equal to the outlet flow of the circulating water pump header， which affects the accuracy of the optimal dispatching calculation of the circulating water system. At present， there is no accurate calculation method for channeling flow. Therefore， a power plant is taken as an example to analyze the composition principle of the closed circulating water system and determine the calculation method of channeling flow based on flow balance. Based on the flow head curve data of the circulating water pump， the mathematical calculation model of channeling flow and the head difference of the circulating water pump closest to the main outlet pipe of parallel units is obtained to realize the online calculation of flow data of all pipelines of circulating water system. Finally， the condenser circulating water flow measured by the heat balance method and the ultrasonic flowmeter is comparatively analyzed. It is recommended to adopt the channeling flow-based calculation method to measure the condenser circulating water flow of units under the operating mode of the expanded unit system.

Mathematical models that describe the dependences of the critical temperatures of pitting formation of AISI 304, 08Kh18N10, AISI 321, 12Kh18N10T steels in model circulating waters with pH 4...8 and chloride concentrations from 350 to 600 mg/l on their chemical composition and structure have been developed. They are based on linear squares regressions and on a feed-forward neural network for a reduced feature numbers. Using the developed mathematical models, it was found that the critical pitting temperatures of these steels increase with an increase in the pH of the circulating water, the amount of oxides up to 3.95 µm in size, the average distance between titanium nitrides, the Cr content and a decrease in the concentration of chlorides in the circulating waters, the average distance between oxides and average austenite grain diameter. At the same time, it was found that the geometric dimensions of the steel structure most intensively affect their pitting resistance in circulating waters, and the effect of their chemical composition is minimal and is determined by the amount of Cr, which contributes to an increase in the pitting resistance of steels, probably increasing the solubility of nitrogen in the austenite solid solution. It is proposed to use the developed mathematical models to select the optimal heats of these steels for the production of heat exchangers and predict their pitting resistance during their operation in circulating waters. [ABSTRACT FROM AUTHOR]

Copyright of Corrosion & Protection in Petrochemical Industry is the property of Corrosion & Protection in Petrochemical Industry 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.)

An accurate and rapid identification of fish feeding intensity can be essential to implement the precise feeding strategies in an industrial recirculating aquaculture system. Feeding intensity can be assessed using single modality indicators, such as water quality, vision, and sound. However, these individual data sources can often provide limited information without the complete picture of feeding behavior. The multimodal data can be expected to incorporate more comprehensive insights, compared with the single modality. Consequently, a more accurate representation of fish feeding intensity can be obtained to reduce some limitations of single modality information. Multi-modal fusion can also offer a novel approach to quantifying the feeding intensity. In this study, a Fish-MulT algorithm was proposed to combine the water quality, sound, and vision data using a Multimodal Transformer algorithm (MulT). Firstly, the feature vectors were extracted from the input water quality, sound, and visual data. Secondly, a Multimodal Transfer Module (MMTM) was employed to fuse the input feature vectors. Adaptive weights were then assigned to the three modalities after fusion. Lastly, the cross-modal transformer of each modal branch in the MulT algorithm was optimized to reduce the number of required transformers from 2 to 1. Furthermore, 1293 sets of threemodality data were collected in the experiment, with 70% used as the training set, 15% as the validation set, and the remaining 15% as the test set. The dataset was classified into four categories, according to the feeding intensity: "strong", "medium", "weak", and "none". The improved model was then evaluated using the collected dataset. Experimental results demonstrate that the Fish-MulT algorithm improved the accuracy of the fish feeding intensity identification from 93.30% to 95.36%, while reducing the number of parameters by 38%, compared with the MulT. Moreover, there were significant improvements in the accuracy, compared with the water quality, sound, and vision data, with the increases of 68.56%, 21.65%, and 3.61%, respectively. An ablation test of the added MMTM module and adaptive weight was also conducted during this time. The addition of both the MMTM module and adaptive weight led to the most significant improvement in the accuracy (up to 95.36%). A substantial improvement was achieved in the recognition accuracy, compared with the single modality. As a result, the Fish-MulT algorithm can be employed to develop precise feeding strategies. The finding can provide technical support to intelligent feeding systems. [ABSTRACT FROM AUTHOR]

Copyright of Corrosion & Protection in Petrochemical Industry is the property of Corrosion & Protection in Petrochemical Industry 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.)

Some beneficiation circulating water contains excess highly dispersed suspended particles, which are difficult to clarify only by simple concentration and sedimentation and cannot meet the requirements of reuse. To solve this problem, a clarification device was developed for removing the solid suspended matter from beneficiation circulating water, which consists of a hydraulic circulation area and a particle sedimentation area and integrating mixing, flocculation, and sedimentation. The flow field inside the gadget has a big influence on how well it works. The structural and operating parameters of the gadget were improved using the computational fluid dynamics approach to increase the device’s performance. A two-dimensional physical model of the deep clarification device for beneficiation circulating water was established. Numerical simulation research on its main structural parameters and operating parameters were conducted by using software Fluent and choosing the Mixture multiphase flow model and RNG k‒ε turbulence model. The effects of feed water nozzle length, throat to nozzle diameter ratio, sludge settling area opening size, and device diameter on the internal flow field were investigated. The average turbulent kinetic energy in the sludge settling zone can be reduced by reducing the length of the nozzle in the hydraulic circulation region, increasing the ratio of the throat to nozzle diameter and the opening size of the sludge settling area, and increasing the diameter of the device. Due to the fact that the turbulent kinetic energy is the kinetic energy of fluid produced by turbulent pulsation, the turbulent degree of the flow field in the sludge settling area is reduced, the effect of turbulent flow in the flow field on particle settling is weakened, and the removal effect of the device on suspended particles is improved. Simultaneously, it is found that at the same suspended solids concentration, reducing the inlet flow rate or increasing the suspended particle size helps to improve the removal rate of suspended solids. When the inlet flow rate is 0.1 m·s-1 and the coagulated suspended particles form particles with particle size more than 100 μm, the removal effect of slime particles in beneficiation circulating water is remarkable.

Organic Rankine cycle (ORC) technology with attractive advantages can be effectively used for low temperature heat recovery. Due to the current research deficiencies and ORC system characteristics in ammonia synthesis manufacturing plant, the developed therm-economic optimization is established, considering the consumption of circulating water subsystem. According to the equilibrium of pay and gain exergy, the coefficient of exergy performance (COEP) of total system is proposed. The behaviors and detailed discussions of the electricity production cost (EPC), which consists of direct energy cost, primary non-energy cost, circulating water subsystem cost, and organic fluid cost, are examined. The exergy and economic comparison is conducted, and optimization is implemented for maximum COEP and minimum EPC. Furthermore, according to evaluation results, there are contradictions between equipment optimization and system optimization in certain operating conditions. Better system performance is achieved in specific evaporation temperature, lower condensation temperature and larger circulating water temperature rise. Under the optimal operation condition, the exergy efficiency of condenser and system is improved by 35.53% and 5.00%, the COEP increases by 1.65, and the EPC is reduced by 0.043 Yuan/kWh, respectively. The annual carbon dioxide emission reduction is developed to 3736.30 tons according to the international specification and the latest carbon dioxide emission factor of power generation in China. The improved therm-economic optimization method is of significance for the selection of optimization methods in practical projects. • The consumption of circulating water subsystem is considered. • The coefficient of exergy performance is proposed. • The improved therm-economic optimization method is of significance in practical projects. • Four components of electricity production cost are examined. [ABSTRACT FROM AUTHOR]

Copyright of Corrosion & Protection in Petrochemical Industry is the property of Corrosion & Protection in Petrochemical Industry 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.)

Oil leakage from water coolers in refinery circulating water occurs from time to time, which affects the long-term and stable operation of refinery units. So far, workers in the refineries still adopt manual check methods, opening water coolers one by one and checking the water's smell and color to find out the spilled water coolers. In this study, a more rapid method of source appointment of oil spill in the circulating water by combining chemical fingerprinting with model recognition was developed. Firstly, chemical fingerprints including benzene/naphthalene series, and light hydrocarbon (C3-C5) in oil samples from all water coolers in the refinery fluid catalytic cracking (FCC) unit were analyzed by gas chromatography-mass spectrometry (GC/MS). Gasoline, diesel, and poor oil could be distinguished in terms of benzene and naphthalene distribution. The three similar types of gasolines could be distinguished by the volatile hydrocarbons especially C3-C4. The classification model for the spill of gasoline, diesel, and poor oil in circulating water was constructed by the partial least squares discriminant analysis algorithm with a 100% correct classification rate at the concentration more than 10 ppm. The gasoline spills in the circulating backwater of the refinery were successfully recognized by the classification model. This method enables the rapid prediction of oil spill type in refinery circulating water, and a similar method by installing online instrument and software potentially can be used for monitoring the circulating water in real time. [ABSTRACT FROM AUTHOR]

Objective The aim of this study is to explore the feasibility of phosphorus-free corrosion and scaling inhibitors in circulating water system of natural gas purification plant. Methods A phosphorus-free corrosion and scaling inhibitor was developed with polyepoxysuccinic acid and zinc salt as the main raw materials. Firstly, the water quality adaptability of the inhibitor was evaluated by means of indoor rotating coupon corrosion test, static scale inhibition test, and microscopic morphology observation, which were followed by field application in the circulating water system of a single natural gas purification plant with a capacity of 150 m3. Results The indoor evaluation results showed that the corrosion rate of carbon steel could be controlled below 0. 02 mm/a and the static scale inhibition efficiency was observed to exceed 90% within the range of calcium hardness of 100-600 mg/L. The field application also confirmed that the CT4-39B has favorable effects since the corrosion rate is far lower than the control value of 0.075 mm/a. At the same time, the total phosphorus contents in circulating water calculated by phosphate radical reduced from 10 mg/L to less than 0. 5 mg/L, which has a positive effect of energy conservation and emission reduction. Conclusions Both the indoor studies and field tests confirm that the phosphorus-free stable operation technology has excellent effects when facing the water with calcium hardness ranging from 100 mg/L to 600 mg/L, and can effectively support the overall environmental protection upgradation of the purification plant while ensuring the stable operation of the circulating water system. [ABSTRACT FROM AUTHOR]

Copyright of Zhejiang Electric Power is the property of Zhejiang Electric Power 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.)

Mathematical models that describe the dependences of the critical temperatures of pitting formation of AISI 304, 08Kh18N10, AISI 321, 12Kh18N10T steels in model circulating waters with pH 4…8 and chloride concentrations from 350 to 600 mg/l on their chemical composition and structure have been developed. They are based on linear squares regressions and a feed-forward neural network for reduced feature numbers. Using the developed mathematical models, it was found that the critical pitting temperatures of these steels increase with an increase in the pH of the circulating water, the number of oxides up to 3.95 μm in size, the average distance between titanium nitrides, the Cr content and a decrease in the concentration of chlorides in the circulating waters, the average distance between oxides and average austenite grain diameter. At the same time, it was found that the geometric dimensions of the steel structure most intensively affect their pitting resistance in circulating waters, and the effect of their chemical composition is minimal and is determined by the amount of Cr, which contributes to an increase in the pitting resistance of steels, probably increasing the solubility of nitrogen in the austenite solid solution. It is proposed to use the developed mathematical models to select the optimal heats of these steels for the production of heat exchangers and predict their pitting resistance during their operation in circulating waters.

Mathematical models that describe the dependences of the critical temperatures of pitting formation of AISI 304, 08Kh18N10, AISI 321, 12Kh18N10T steels in model circulating waters with pH 4...8 and chloride concentrations from 350 to 600 mg/l on their chemical composition and structure have been developed. They are based on linear squares regressions and on a feed-forward neural network for a reduced feature numbers. Using the developed mathematical models, it was found that the critical pitting temperatures of these steels increase with an increase in the pH of the circulating water, the amount of oxides up to 3.95 µm in size, the average distance between titanium nitrides, the Cr content and a decrease in the concentration of chlorides in the circulating waters, the average distance between oxides and average austenite grain diameter. At the same time, it was found that the geometric dimensions of the steel structure most intensively affect their pitting resistance in circulating waters, and the effect of their chemical composition is minimal and is determined by the amount of Cr, which contributes to an increase in the pitting resistance of steels, probably increasing the solubility of nitrogen in the austenite solid solution. It is proposed to use the developed mathematical models to select the optimal heats of these steels for the production of heat exchangers and predict their pitting resistance during their operation in circulating waters. [ABSTRACT FROM AUTHOR]

The aim of this work is decreasing the weight-size parameters of the contact gas-steam turbine plant and contact condenser elements by increasing the efficiency of thermal-gas dynamic processes of condensation through rational irrigation of countercurrent gas-steam flow. To achieve the goal the total efficiency of water-return drops ranging from 0.1 to 1 mm at different initial velocities from 5 to 35 m/s emitted by the multi-nozzle sprinkler was determined by mathematical modeling of the liquid droplet movement processes, heat and mass transfer between the liquid droplet and gas-vapor mixture, and gas-vapor mixture pressure loss. The effect of increasing the gas-steam mixture velocity from 3.3 to 6 m/s on the overall efficiency of water return was determined. The novelty of the obtained results was defined by an increase in the water return into cycle from 12 to 13% with a droplet diameter of 0.3 -- 0.4 mm and the initial velocity from the sprinkler of 5--10 m/s. The velocity of the mixture was to 6 m/s at rational correlations of the initial velocity of the droplets’ escape, which increased the total amount of heat withdrawn to 11%. The positive effect conditions of irrigation processes on thermogasdynamic and weight-size parameters of the condenser elements for the contact gas and steam turbine plant at full pressure recovery coefficients of over 0.967 were substantiated. The most significant result was the reduction of the weight-size parameters of the marine infrastructure object power plant from 8 to 19%.

We develop a mathematical model of dependences of the critical pitting temperature of AISI304 steel on its chemical composition, structural heterogeneity, pH value of circulating water, and the concentration of chlorides. It is shown that the influence of model circulating waters on the critical pitting temperature of steel is twice more intense than the influence of the other characteristics. In particular, it is shown that the critical pitting temperature of steel increases by 13.4°C as the concentration of chlorides decreases from 600 down to 350 mg/liter. At the same time, it increases only by 5.8°C as the Cr content of steel increases from 17 up to 19.5 wt.%. This is connected with the formation of a dense chromium-containing oxide film on the steel surface, which efficiently prevents pitting and decreases the rate of solid-phase diffusion of Fe atoms to the surface of pits, which may promote their repassivation. It is shown that the critical temperature of pitting of steel increases by 5.2°C as the mean distance between oxides increases from 151 up to 172 μm. Thus, the larger the mean distance between oxides in steel and the mean diameter of austenite grains, the lower the probability of its intersection with grain boundaries, where the formation of stable pits is most probable. It is proved that the higher the Cr content of steel and the finer the oxides formed there, the higher the pitting resistance of steel. We recommend to use the developed mathematical model for the prediction of pitting resistance of heat exchangers made of AISI304 steel operating in circulating waters and for the choice of the optimal parameters of melting. [ABSTRACT FROM AUTHOR]

It has been proposed that the discharge of stack gases of the waste heat recovery boiler of a gas-turbine installation into the atmosphere be carried out through the stack of a cooling tower with natural air ventilation. A technique and a PC computational program have been developed for the processes of heat and mass transfer during the motion of a gas–air mixture in the stack of a cooling tower. A calculation has been performed for the processes of heat and mass transfer occurring in a chimney-type cooling tower installed at a 200 MW CCGT (combined cycle gas turbine) unit of the Syzran′ CHP (combined heat and power plant) for two variants of its operation: without discharge or with discharge of stack gases from two heat recovery boilers into the atmosphere. The calculations have been performed for the summer period of the year. The analysis of the calculation results has shown that the proposed technical solution allows an additional reduction in the temperature of the circulating water at the outlet from the cooling tower by 1.31°C (from 28.08 to 26.77°C) and a rise in the efficiency of the combined cycle gas turbine unit up to 50.82%, i.e., by 0.08%. [ABSTRACT FROM AUTHOR]

Objective The cause for corrosion in heat exchangers at a single natural gas purification plant located in Sichuan-Chongqing area was studied as well as the influencing factors so as to reach the technical solutions. Methods Microscopic analysis was conducted to study the cause for leakage in the tube bundles while the influences of Ca2+ alkalinity, Cl- and SO2-4 in the circulating water on corrosion rate were investigated by rotary hanging plate method. Results The leakage in the heat exchange tube bundle was caused by corrosion. During the process, corrosion occurred first at the inner surface of the tube bundle, which then gradually grew to form corrosion holes and finally led to the leakage. Ca2+ and alkalinity were revealed to be closely related with the corrosivity of the recirculating water: when the Ca2+ concentration was as low as 44 mg/I., the corrosion rate of the carbon steel could reach as high as 1.05 mm/a. Conclusions In order to prevent the corrosion failure of tube bundle, it is necessary to enhance the water quality control by increasing the Ca2+ concentration and alkalinity in the system or using material with higher corrosion resistance. [ABSTRACT FROM AUTHOR]

The design and operating principle of an original apparatus for obtaining purified fresh water are presented. Within the body of the apparatus three zones are combined sequentially: the zone of input of the source water and its distribution over the volume of the apparatus; the zone of freezing of the source water with the formation of an ice rod (with the impurities concentrating in the center as brine); the zone of defrosting purified water with an external heating element. The developed apparatus can be used to purify circulating water of refinery electrical desalination units. [ABSTRACT FROM AUTHOR]

We develop mathematical models used to describe the dependences of the critical pitting temperatures of AISI 321 steel in model circulating waters with pH 4–8 and a concentration of chlorides varying within the range 350–600 mg/liter on its chemical composition and structure. These models are based on multidimensional linear regressions of the first order and neural networks with forward signal propagation. By using the developed mathematical models, it is established that the critical pitting temperatures of AISI 321 steel become higher as the pH value of the circulating water, the mean distance between oxides in the steel, and the contents of manganese and chromium increase and as the mean grain diameter of austenite and the content of chlorides in the medium decrease. At the same time, it is shown that the influence of the medium is most pronounced but the heterogeneity of steel, which depends on the contents of Cr, Si, Mn, and N, also strongly affects its pitting resistance. It is proposed to use the developed mathematical models for the choice of the optimal heats of AISI 321 steel guaranteeing its highest pitting resistance in model circulating waters. [ABSTRACT FROM AUTHOR]

The solution of the sludge utilization problem and yield increase at processing plants have great importance today all over the world. Disasters associated with the tailings dams failures have madeus develop technologies of tailings sludge utilization as a commercial product, reducing the environmental damage on the regions of mineral extraction. This research aimed to provide new data, methods and an analytical approach to solve the saponite sludge accumulation problem on mining enterprises with silicate coagulant to increase the rate of cycle water clarification for the enrichment process and the recycling of sludge to reduce its hazardous effect. Samples were taken in the deposit located in the north of the European part of Russia, where diamond bearing ore contain montmorillonite minerals, mostly saponite, which is considered to be a perspective secondary product. The content of this mineral in the sludge is above 20 wt.%. Saponite is a clay mineral with the general chemical formula (Ca,Na)0.3(Mg, Fe2+)3(Si, Al)4O10(OH)2·4H2O. The mineral has high adsorption, ion exchange, and catalytic and filtration properties; due to the developed diffuse layer, saponite particles are highly stable in an aqueous medium—the resulting suspension is highly stable and has slow sedimentation. During the research, a positive effect on the sedimentation process of clay saponite particles was established, due to the introduction of a coagulant containing 70% tricalcium silicate, at a dosage of 2 g/dm3 coagulant; the degree of purification of water containing the saponite clay suspension is 99%. The condensed sediment after the thermal drying and with the limestone addition can be used again as a coagulant or secondary product with enhanced properties;therefore, the sludge will be processed, and not stored. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering for Thermal Energy & Power / Reneng Dongli Gongcheng is the property of Journal of Engineering for Thermal Energy & Power 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.)

Copyright of Petroleum Refinery Engineering is the property of Petroleum Refinery Engineering 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.)

A new construction of the cooling tower sprinkler block consisting of jet–film contact devices has been developed. The proposed packings are capable of increasing the surface of contact of phases at a small number of wetting points, a minimum percent of droplet entrainment by a gas flow, and a low hydraulic resistance. Based on the method of transfer units, generalizing the results of experimental investigations of the process of water cooling in the developed cooling tower sprinkler block, an expression has been obtained for calculating the volumetric coefficient of mass transfer with account for the ratio between the mass flow rates of air and water, as well of the wetting density. It has been established that an increase in the mean-flow speed of air leads to an increase in the values of the volumetric coefficient of mass transfer because of the increase in the degree of gas flow turbulence. Comparison results of calculations of the volumetric coefficient of mass transfer for different cooling tower sprinkler blocks are given. It has been established that at small ratios of unit loads (Gm/Lm up to 0.5) a sprinkler made of lattice elements is most efficient. It has been proven that on increase of the ratio of init loads (Gm/Lm > 0.5), the sprinkler block consisting of the proposed jet–film contact devices has the highest cooling capability. The expression obtained for calculating the volumetric coefficient of mass transfer can be used in designing and modernization of industrial, cooling towers with jet–film contact devices. [ABSTRACT FROM AUTHOR]

The solution of the sludge utilization problem and yield increase at processing plants have great importance today all over the world. Disasters associated with the tailings dams failures have madeus develop technologies of tailings sludge utilization as a commercial product, reducing the environmental damage on the regions of mineral extraction. This research aimed to provide new data, methods and an analytical approach to solve the saponite sludge accumulation problem on mining enterprises with silicate coagulant to increase the rate of cycle water clarification for the enrichment process and the recycling of sludge to reduce its hazardous effect. Samples were taken in the deposit located in the north of the European part of Russia, where diamond bearing ore contain montmorillonite minerals, mostly saponite, which is considered to be a perspective secondary product. The content of this mineral in the sludge is above 20 wt.%. Saponite is a clay mineral with the general chemical formula (Ca,Na)0.3(Mg, Fe2+)3(Si, Al)4O10(OH)2·4H2O. The mineral has high adsorption, ion exchange, and catalytic and filtration properties; due to the developed diffuse layer, saponite particles are highly stable in an aqueous medium—the resulting suspension is highly stable and has slow sedimentation. During the research, a positive effect on the sedimentation process of clay saponite particles was established, due to the introduction of a coagulant containing 70% tricalcium silicate, at a dosage of 2 g/dm3 coagulant; the degree of purification of water containing the saponite clay suspension is 99%. The condensed sediment after the thermal drying and with the limestone addition can be used again as a coagulant or secondary product with enhanced properties;therefore, the sludge will be processed, and not stored.

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To enhance the energy utilization and waste collection efficiency in a recirculating aquaculture system (RAS), this study investigates the hydrodynamic performance of a square arc-corner aquaculture tank using various combined water-jet inlets. An experimental verification system was developed for the recirculating aquaculture tank (RAT) to validate the accuracy of the computational fluid dynamics (CFD) model. This was achieved by comparing flow velocities at various monitoring points. A comprehensive analysis of the tank's hydrodynamic performance was conducted, encompassing velocity distribution, vorticity strength, flow uniformity index, resistance coefficient, Froude number, energy utilization efficiency, and particle removal rate. The results clearly showed that incorporating combined water-jet inlets greatly improved the hydrodynamic performance of the tank compared to traditional one-way inflow patterns. The combined injection method ensured a more uniform flow velocity both longitudinally and radially throughout the RAT, effectively reducing the concentration of water flow in a single direction. Additionally, the tangential injection of water flow along the tank wall promoted a more even flow rate, enhancing water mixing and maintaining a homogeneous distribution of dissolved oxygen. By arranging and spacing the injection holes appropriately, the fluidity and mixing of water were enhanced, leading to increased energy utilization and improved efficiency in pollutant collection. • A design scheme was proposed for a combined water-jet inlet pipe in a square arc-corner aquaculture tank, and its hydrodynamic characteristics were compared with the traditional unidirectional water inlet pipe. • A two-phase flow numerical method was developed to investigate the hydrodynamic characteristics and self-purification efficiency of RATs. • The study examined the effects of inlet pipe position, nozzle spacing, and jet angles on various hydrodynamic parameters. [ABSTRACT FROM AUTHOR]

For circulating cooling systems, the solid mineral sediments formed as a result of crystallization of sparingly soluble inorganic salts in the transition of circulating water in the supersaturated state are the most dangerous. Aim: The aim of this research is to study the intensity of sediments of hardly soluble salts crystals on the surfaces of the heating of evaporative cooling equipment and condensers from supersaturated circulating water in the circulating cooling systems of power plants with water cooling towers. Materials and Methods: The methodology of the research was to study the mass and size of the hardly soluble crystals in circulation water and sediments on heat exchange surfaces of the condenser and the evaporator surface of the water cooling tower. Source water for the experiment was selected from Styr river. Experimental studies were carried out at the installation of a scale model of circulation cooling system. To study the nature of the interaction of the solid phase particles with each other in the starting water and the circulating used the method of dispersion analysis of coarse phase particles in the optically scanned water layer. Results: The study the intensity of sediments sparingly of soluble salt crystal on the surfaces of the heating of evaporative cooling equipment and condensers from supersaturated circulating water in the circulating cooling systems of power plants with water cooling towers were held. It has been determined that as the circulation water is cooling, with its runoff along the cooling surface and aeration by counter-steam mass flow there are salinity increase and increase the weight of precipitated carbonate salts crystals, which ultimately leads to the formation of loose sediments in the unheated watering surfaces of water cooling towers. Allocation of crystallization centers of sparingly soluble carbonate salt when it is heated in the heat exchange condenser tubes is due to the thermal dissociation of good soluble bicarbonate salts into sparingly soluble carbonate salts and then sediment at the heated tubes surface.

The paper analyzes the connection between processing technologies of circulating water cooling tower and coagulation-aggregation properties of colloidal particles of the dispersed phase. In circulating water cooling tower when clarifying additional water the reduction of HCO3- and CO32- concentrations happens with corresponding pH increase. Absorption of atmospheric carbon dioxide by cooling tower circulating water offsets this increase. The estimation of the probability of adhesion to the surface of the dispersed phase, distributed in the volume of circulation water, and the heat exchange surface of the condenser for different degrees of evaporation of the coolant is made. The distribution of cooling water micro-disperse particles which are adsorbed on the heat exchange surfaces of the condenser (deposit formation) and on the surface of larger particles (particle aggregation) reflects the efficiency of applied water treatment technology. It is shown that acidification of additional water facilitates solution of most fine fractions and increases hardness of treated water.

Abstract Several studies in the last several years have shown that slope stability and the physical–mechanical properties of sediments can be influenced by their granulometrical, chemical and mineralogical characters and circulating water chemistry, which highlights the importance of studying these processes using a multidisciplinary approach. Two landslides, in a well-known geological area in the Southern Apennines impacted by many landslides, were studied to integrate geological and geomorphological surveys and geotechnical tests with the compositional characterization of the sediments and circulating waters and through a careful definition of the tipology and intensity of the weathering processes. Pliocene clays and Oligocene slates affected by the studied landslides were characterized for mineralogical, chemical and grain-size composition and these compositional characters were compared with their physical (Atterberg limits, plasticity, activity) and mechanical (friction angle, cohesion, residual shear strength) properties. These properties were determined using distilled water, waters circulating in the landslide sediments and saline solutions that amplify seasonal chemical variations. The compositional and physical-mechanical properties of the sediments were compared with the slip and low deformation zone positions, detected in situ from inclinometer measurements, in order to identify any anomalies in the weak zones along the stratigraphic column. The results showed some correlations between the compositional characters of sediments (grain size, mineralogy and geochemistry) and the slip zone position, and highlighted that the chemistry of the circulating waters can modify certain physical-mechanical behaviours. However, the magnitude and modalities of such influences depends strongly on the geological history and lithotypes involved in the sliding. The Pliocene clay landslide was found to have several slope instability risk factors, such as kaolinite content and water salinity, while the physical-mechanical properties of the Oligocene slates were demonstrated to be less sensitive to sediment and water compositional characters. Finally, significant correlations were detected between the position of the slip zone and the degree of sediment chemical alteration using a new weathering index specifically designed for the sediments studied. These results demonstrate that the study of landslides must not ignore the compositional characterization of the sediments and waters, as certain chemical or mineralogical features can represent important risk factors contributing to the worsening of the slope stability and the triggering of the slip. Highlights • Water salinity can modify some physical-mechanical behaviours of sediments. • Kaolinite is a mineralogical risk factor for the slope stability in Pliocene clays. • Correlations exist between slip zones and chemical alteration degree of sediments. • Weathering trend is a possible tool for the identification of mechanical weak zones. • The rock/water interaction processes are essential to understand landslides. [ABSTRACT FROM AUTHOR]

The process of cooling of circulating water in miniature cooling towers with roll packing possessing a rough surface is considered. The specific surface of the corrugated surface is 250 m/m. The hydraulic characteristics of the packing over a broad range of water and air flow rates are presented. Expressions for calculating the thermal efficiency of the cooling tower and the results of a calculation of the hydraulic and heat and mass exchange characteristics with elevated flow rates of the cooled water to 60 m/(m·h) are given. The advantages of a miniature cooling tower with roll packing are demonstrated. [ABSTRACT FROM AUTHOR]

As a greenhouse gas, carbon dioxide (CO2) is one of the major causes of global warming. The effective control of CO2 emission has become a major global concern. To reduce CO2 emission in the environment and to maximize the use of CO2, a self-cooling wire-cylinder dielectric barrier discharge (DBD) plasma reactor was used to decompose CO2 at ambient conditions, and the results were compared with a common wire-cylinder DBD reactor. Results indicated that in the said plasma reactor, circulating water could obviously improve discharge efficiency through taking away heat that was generated during plasma discharge process, and a more stable and homogeneous discharge was easier to obtain. The CO2 decomposition rate was 26.1% without using any catalysts and discharge mediums or modifying electrodes, and this value was significantly higher than that in the common wire-cylinder DBD reactor (10.1% CO2 decomposition rate). Moreover, the CO2 decomposition rate could reach up to 35.8% when N2 was added (volume ratio [ABSTRACT FROM AUTHOR]

To improve the utilization of energy input from inlet pipe jets and the efficiency of waste collection in a recirculating aquaculture system (RAS), the hydrodynamics and self-purification efficiency of square fillet aquaculture tanks were studied under different numbers of inlet pipes and particle physical properties. First, a numerical model was established by reference to the experimental model, and the validity of the numerical method was verified by comparing the experimental results. Then, the hydrodynamics of the aquaculture tanks were analyzed, including velocity distribution, vorticity strength, energy utilization efficiency, flow uniformity index and self-purification efficiency. Finally, the discharge rates of particles at overflow and underflow with different densities and diameters were also analyzed. The results reflect that the swirling velocity, flow uniformity index, energy utilization efficiency, turbulence and secondary flow intensity increase under steady injection, which is conducive to improving the self-purification efficiency in the RAS. In the case of a single inlet pipe and a particle density of 1300 kg/m3, the discharge rate is the highest, and the residence time is relatively short. The smaller the particle size is, the longer the residence time and the lower the discharge rate. The larger the particle size is, the faster the removal rate increases, and the effect is not obvious for particles larger than 2.0 mm in diameter. The inclusive analysis not only explores the hydrodynamics in aquaculture tanks with different water injection structures but also recommends RAS structural optimization design. [ABSTRACT FROM AUTHOR]

The Vistula Lagoon - one of the main recipients of the central and eastern parts of the Vistula delta - is not homogeneous in terms of its hydrodynamics and hydrochemistry. In the southern part a separate hydrographic object- the Gulf of Elbląg - can be delimited. This delimitation is due to different morphometric and hydrometeorological conditions that prevail in this part of the Vistula Lagoon. In order to determine the nature of the waters, measurements of the selected physico-chemical properties, including chlorides, as well as control hydrological measurements were performed in the years 1997-2007. The study area included the water of the Gulf of Elbląg, the estuary stretch of the Elbląg River, the watercourses flowing from the Elbląg Plateau and the polder areas surrounding the Gulf of Elbląg. One measurement point was located on the Vistula Lagoon. The chloride values in the Gulf of Elbląg ranged from 20 to 2015 mg⋅dnr³. The results may indicate that the Gulf of Elbląg is a reservoir under the hydrodynamic and hydrochemical influence of both the Vistula Lagoon and the watercourses in its mouth, as well as the Vistula delta and the Elbląg Plateau. They dictate the seasonal nature of the waters of the Gulf of Elbląg. [ABSTRACT FROM AUTHOR]

Different approaches to simulation of momentum, mass, and energy transfer in packed beds are considered. The mathematical model of heat and mass transfer in a wetted packed bed for turbulent gas flow and laminar wave counter flow of the fluid film in sprinkler units of a water-cooling tower is presented. The packed bed is represented as the set of equivalent channels with correction to twisting. The idea put forward by P. Kapitsa on representation of waves on the interphase film surface as elements of the surface roughness in interaction with the gas flow is used. The temperature and moisture content profiles are found from the solution of differential equations of heat and mass transfer written for the equivalent channel with the volume heat and mass source. The equations for calculation of the average coefficients of heat emission and mass exchange in regular and irregular beds with different contact elements, as well as the expression for calculation of the average turbulent exchange coefficient are presented. The given formulas determine these coefficients for the known hydraulic resistance of the packed bed element. The results of solution of the system of equations are presented, and the water temperature profiles are shown for different sprinkler units in industrial water-cooling towers. The comparison with experimental data on thermal efficiency of the cooling tower is made; this allows one to determine the temperature of the cooled water at the output. The technical solutions on increasing the cooling tower performance by equalization of the air velocity profile at the input and creation of an additional phase contact region using irregular elements 'Inzhekhim' are considered. [ABSTRACT FROM AUTHOR]

For circulating cooling systems, the solid mineral sediments formed as a result of crystallization of sparingly soluble inorganic salts in the transition of circulating water in the supersaturated state are the most dangerous. Aim: The aim of this research is to study the intensity of sediments of hardly soluble salts crystals on the surfaces of the heating of evaporative cooling equipment and condensers from supersaturated circulating water in the circulating cooling systems of power plants with water cooling towers. Materials and Methods: The methodology of the research was to study the mass and size of the hardly soluble crystals in circulation water and sediments on heat exchange surfaces of the condenser and the evaporator surface of the water cooling tower. Source water for the experiment was selected from Styr river. Experimental studies were carried out at the installation of a scale model of circulation cooling system. To study the nature of the interaction of the solid phase particles with each other in the starting water and the circulating used the method of dispersion analysis of coarse phase particles in the optically scanned water layer. Results: The study the intensity of sediments sparingly of soluble salt crystal on the surfaces of the heating of evaporative cooling equipment and condensers from supersaturated circulating water in the circulating cooling systems of power plants with water cooling towers were held. It has been determined that as the circulation water is cooling, with its runoff along the cooling surface and aeration by counter-steam mass flow there are salinity increase and increase the weight of precipitated carbonate salts crystals, which ultimately leads to the formation of loose sediments in the unheated watering surfaces of water cooling towers. Allocation of crystallization centers of sparingly soluble carbonate salt when it is heated in the heat exchange condenser tubes is due to the thermal dissociation of good soluble bicarbonate salts into sparingly soluble carbonate salts and then sediment at the heated tubes surface. [ABSTRACT FROM AUTHOR]

This paper summarizes an engineering experience of solving the problem of thermal cracking in mass concrete by using a large project, Zhongguancun No.1 (Beijing, China), as an example. A new method is presented for controlling temperature cracks in the mass concrete of a foundation. The method involves controlled cycles of water circulating between the surface of mass concrete foundation and the atmospheric environment. The temperature gradient between the surface and the core of the mass concrete is controlled at a relatively stable state. Water collected from the well-points used for dewatering and from rainfall is used as the source for circulating water. Mass concrete of a foundation slab is experimentally investigated through field temperature monitoring. Numerical analyses are performed by developing a finite element model of the foundation with and without water circulation. The calculation parameters are proposed based on the experiment, and finite element analysis software MIDAS/CIVIL is used to calculate the 3D temperature field of the mass concrete during the entire process of heat of hydration. The numerical results are in good agreement with the measured results. The proposed method provides an alternative practical basis for preventing thermal cracks in mass concrete. [ABSTRACT FROM AUTHOR]

In this article, a simple and sensitive spectrometric method used for determination of polyepoxysuccinic acid (PESA) in circulating water was investigated. The availability of this method depends on the turbidity formed by PESA and dodecyl dimethyl benzyl ammonium chloride (1,227). In order to obtain the optimal experimental conditions, influencing factors such as dosage of 1,227, pH value, and stabilization time were discussed. Interferences of coexisting substances which may hamper the determination of PESA were also studied. The optimal experimental conditions were as follows: 1,227 concentration of 250 mg L−1, pH range of 9–10, and stabilization time of 30 min. Under these conditions, a better linear relationship between absorbance and concentration was observed within a PESA concentration range of 0–16 mg L−1. It was also demonstrated that foreign ions (i.e.,, Cl−, Fe2+) and water quality stabilizers (i.e. 1,2,3-benzotriazole and 1-hydroxy ethylidene-1, 1-diphosphonic acid) had no influences on the determination. In addition, interferences of Ca2+and Mg2+can be eliminated by adding a desired amount of ethylenediamine tetraacetic acid disodium salt. To minimize the influence of sodium hexametaphosphate, a proper amount of HCl was added into the solution, and then it was boiled after mixing. In summary, this method is very simple, concise, and accurate with a lower detection limit, which could provide a theoretical and practical guidance for the determination of PESA. [ABSTRACT FROM PUBLISHER]