Moisture Separation Research Articles

An Experimental Investigation into Nozzle Vane Heating to Prevent Erosion in the Last Stages of Steam Turbines

The paper is devoted to an experimental investigation of nozzle vane heating in the last stage of a wet steam turbine. The investigation was performed at a steam-dynamic test facility whose circuit was connected to an operating cogeneration power station (TETs). The working fluid was steam from a heat extraction assembly of a steam turbine. To prepare a polydisperse wet steam flow specific for the last stages of steam turbines, a three-stage wetting system based on feedwater injection into the flow was used. The object of investigation is a flat vane cascade consisting of hollow vanes. The vane cavities are fed with superheated steam to provide heating. Experimental data are presented demonstrating that it is advisable to heat nozzle vanes: first, the economic characteristics are improved, and, second, erosion of the blades in the last stages decreases. This method can be used as an alternative to the internal moisture separation from the steam path. The experimental investigation yielded the effect of the temperature difference between the main flow and the heating steam on the amount of heat transferred to the main flow and on the steam conditions at the outlet from the heating chamber. It was found that condensation in the heating chamber decreased its outlet pressure. This should be considered in designing a similar active system to control erosion of rotor blades. The measured profile losses of kinetic energy downstream of the vane cascade for different temperature difference values are presented. The kinematic characteristics of the liquid phase downstream of the vane trailing edge are determined. Large temperature differences are found to have a negative effect on droplets and can reduce the erosion resistance of the blades as compared with profiles without any active erosion control methods.

Full-scale numerical study on the flow characteristics and mal-distribution phenomena in SG steam-water separation system of an advanced PWR

The steam-water separation system is of great importance to ensuring the steam quality in a PWR UTSG. In the present work, the full-scale three-dimensional CFD analysis is performed to study the mal-distribution steam flow in the system using ANSYS-FLUENT platform. A full-scale model of newly-designed PWR is established and all the sophisticated structures of 19 swirl-vane separators are modeled. Besides, the porous medium model is adopted to simplify the steam flow inside the dryers because of the complex structure of wave-type vanes. Employing CFD methodologies, detailed flow characteristics in the whole system are captured, especially the velocity fields of steam at inlets of 7 dryer units. The outcomes show that the maximum unit-area mass-flow rate appears at the entrance of #4 dryer which is in the central part of dryers. In addition, the maximum entry velocity is 2.136 m/s, while the velocity is decreased to 1.049 m/s, lower than the critical velocity, with the application of an orifice plate assembly with the perforation in different calibers on the plate. Also, the effect of the separator down-comer on the mal-distribution phenomenon is also analyzed. In general, the current work could be expected to be a basis for the future optimization on moisture separation components in the steam generator.

PENGARUH PERBANDINGAN BUBUK KULIT ARI BIJI KAKAO : EKSTRAK KULIT BUAH JERUK NIPIS DAN WAKTU PENGADUKAN TERHADAP KARAKTERISTIK BODI KRIM

Cream is a cosmetics in the form of a half-solid emulsion. This study aims to determine the effect of the comparison of the bark powder of the cocoa beans : extract of lime peel and the stirring time on the characteristics of body cream, determine the comparison of the bark powder of the cocoa beans : extract of lime peel and the stirring time that is best to produce body cream. This study uses factorial completely randomized design with 2 factors. The first factor is the comparison of the bark powder of the cocoa beans : extract of lime peel. The second factor is the stirring time of the body cream. The variables observed were material moisture content, pH, viscosity, dispersion, separation ratio, antioxidant capacity and color intensity. The results showed that the comparative treatment of the addition of the bark powder of cocoa beans and lime peel extract had a very significant effect on pH, dispersion, antioxidant capacity, brightness level (L*), redness level (a*), and yellowish level (b*) cream. The stirring time treatment has a significant effect on the brightness level (L *) of the cream. Comparative treatment of adding the bark powder of cocoa beans and extracts of lime peel, stirring time and interaction between the two treatments has a very significant effect on the viscosity of the cream. The comparison of the addition of the bark powder of cocoa beans : lime peel extract are 7.14: 7.14 grams and 15 minutes of stirring time was the best treatment, which can produce body cream with characteristic of pH 6,35, dispersion level 6,10 cm, viscosity 28.100 cp, separation ratio = 1, antioxidant capacity 125, 33 mg GAEAC/L, brightness level (L*) 43,78, redness level (a*) 6,73 and yellowish level (b*) 10,56.
 Keywords : body cream, addition of ingredients, and stirring time.

Vertical steam generators for VVER NPPs

Steam generators for NPPs are the important large-sized metal consuming equipment of nuclear power installations. Efficiency of steam generator operation determines the overall service life of the whole nuclear facility. The main aim of the current study is to analyze advantages and shortcomings of horizontal and vertical types of steam generator design. This analysis is aimed at the development of recommendations for designing advanced steam generators for future Russian units of NPPs with VVER reactors of increased power. Design solutions and fifty-year experience of operation of 400 steam generators of horizontal type accepted in Russia and of vertical type applied by Westinghouse, Combustion Engineering, Siemens, Mitsubishi, Doosan were analyzed within the framework of the present study. Advantages and drawbacks of both types of equipment determining the development of conditions of the operating processes were also identified and systematized. Currently NPPs equipped with VVER are characterized with extended surface area of containment shells due to the application of four-loop design configuration and horizontal-type steam generators. It was established that steam generator equipment of horizontal type is characterized by such inherent disadvantages of design, technological and operational nature as the following: 1) small height and volume of the vapor space above the evaporation surface reducing separation capabilities and the capacity of the equipment as a whole; 2) impossibility of organizing separate single-phase pre-boiling section. Because of the above, horizontal steam generators with dimensions permissible for railroad transportation and, for VVER-1200 with reactor vessel diameter equal to 5 m, by water transport as well, have exhausted the possibilities for further significant increase of the per unit electric power. The demonstrated advantages of vertical-type steam generators were as follows: 1) absence of stagnant zones within the second cooling circuit, and, consequently, of hold-ups in them; 2) uniformity of heat absorption efficiency of the heating surface ensuring, as well, improved conditions for moisture separation; 3) high degree of moisture removal from steam-water mixture due to the combination of moisture separating elements of chevron and swirl-vane types; 4) increased temperature drop with parameters of generated steam elevated by 0.3 – 0.4 MPa. Conclusion was made on the advisability of introduction of steam generators with vertical-type layout in the Russian nuclear power generation. Practical tasks that need to be addressed in order to ensure introduction of vertical steam generators at NPPs with high-power VVER reactors were formulated.

Ways for Improving Efficiency and Reliability of Steam Turbines at Nuclear Power Stations

The current state and ways for improving the effectiveness of steam turbine units at nuclear power stations (NPS) are examined. The specifics of NPS turbines is described. The comparison of NPS steam turbine performance with the performance of steam turbines at thermal power stations (TPS) demonstrates that power units of NPSs are much poorer in effectiveness due to relatively low steam conditions at the inlet and the presence of wet steam already in the first stages of turbines. A decrease in the relative internal efficiency of NPS turbines results from the enhanced negative effect of wetness in the expansion process: in modern NPS turbines, more than two-thirds of the heat drop is spent in the two-phase region, while less than one fourth in TPS turbines. It is demonstrated that the effectiveness of NPS steam turbine units can be increased drastically in the future only through a considerable rise in the turbine inlet steam conditions. This can be achieved by using a heat carrier at supercritical conditions in the NPS reactor. The dependence of the effectiveness of NPS modern turbines on the turbine inlet steam conditions in the applicable pressure ranges of the saturated steam and vacuum in the condenser, as well as on the turbine exhaust area, is examined. For a 1000 MW turbine, increasing the inlet pressure from 6.0 to 8.0 MPa raises the turbine power and efficiency by 3.5%. At a condensing turbine outlet pressure ranging from 2.5 to 7.5 kPa and a constant velocity downstream of the last stage, the turbine power and efficiency can be increased by 7%. The importance of the exhaust area for the turbine effectiveness is revealed. Alternative designs of the flowpath in a low-pressure cylinder are analyzed. A unique configuration of a steam turbine unit with two-stage moisture separation is proposed. The comparison of high-speed turbines with low-speed ones was performed. It is demonstrated that the efficiency of the examined turbines is nearly the same within the accuracy of design calculations and the test results, and it is slightly higher for low-speed turbines due to lower losses with outlet velocity.

Reversibility of Brominated Carbon Electrodes for Lithium-Bromide Battery Applications

Lithium-ion batteries provide, on average, a near 150 Wh/kg energy density and capacity near 170 mAh/g [1]. Other lithium energy storage chemistries such as lithium-air and lithium-sulfur have been proposed as potential higher energy (11680[2], 2500[3] Wh/kg) capacity alternatives; however, various issues plague these battery types, ultimately affecting the energy and performance. Lithium-air batteries suffer from poor cyclability (~60-70% efficiency) and materials issues stemming from moisture and poor separation of environmental contaminants[2]. Lithium-sulfur suffer from capacity fading (>10% over 100 cycles) and loss of active material due to polysulfide dissolution[5]. Recently, studies using a lithium-bromide chemistry have shown promising results as a rechargeable alternative to lithium-ion batteries, including energy densities of 1220 Wh/kg[6] and efficiencies between 90%[7] and 99.5%[8]. In order to investigate the viability of rechargeable lithium-bromide batteries, studies were conducted with graphite and brominated electrodes in an electrolyte utilizing the highly soluble Br3 -/Br- redox couple. Characterization of the electrodes and brominated particles were completed using X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDS), and Transmission Electron Microscopy (TEM). From electrochemical experiments, Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS), the electrodes display behaviors consistent with pseudo-batteries, containing both capacitive and faradaic responses; additionally, higher activity (up to 2x the current density of untreated graphite) is seen with the brominated electrodes. The results of these analyses will be presented, and the implications for rechargeable lithium-bromide batteries will be discussed.

Modern geothermal power: GeoPP with geothermal steam turbines

The first part of the review presents information on the scale and specific features of geothermal energy development in various countries. The classification of geothermal power plant (GeoPP) process flow diagrams by a phase state of the primary heat source (a geothermal fluid), thermodynamic cycle, and applicable turbines is proposed. Features of geothermal plants using methods of flashing and steam separation in the process loop and a flowsheet and thermodynamic process of a geothermal fluid heat-to-power conversion in a GeoPP of the most widespread type using a double-flash separation are considered. It is shown that, for combined cycle power units, the specific power-to-consumption geothermal fluid ratio is 20–25% higher than that for traditional single-loop GeoPP. Information about basic chemical components and their concentration range for geothermal fluids of various formations around the world is presented. Three historic stages of improving geothermal energy technologies are determined, such as development of high-temperature geothermal resources (dry, superheated steam) and application of a two-phase wet-steam geothermal fluid in GeoPP power units with one or two expansion pressures and development of binary cycle GeoPPs. A current trend of more active use of binary power plants in GeoPP technological processes is noted. Design features of GeoPP’s steam turbines and steam separating devices, determined by the use of low-potential geothermal saturated steam as a working medium, which is characterized by corrosion aggressiveness and a tendency to form deposits, are considered. Most promising Russian geothermal energy projects are determined. A list of today’s most advanced geothermal turbine performance technologies is presented. By an example of a 25 MW steam turbine design, made by JSC Kaluga Turbine Works, advantages of the internal moisture separation with a special turbine-separator stage are shown.

Simulation on mechanism of contamination mitigation through Higee and hydrocyclone techniques in fluid power system

In this study, an innovative Higee hydraulic oil purification device capable of removing the solid particle contaminants and water moisture simultaneously is developed for dealing with the contamination control problem of fluid power systems. The purification device is considered as a combination of two units (hydrocyclone separator and rotating packed bed) according to different separation functions. The mathematical models about the migration regularity and dynamic behavior of different phases have been established, in which discrete phase model model is employed to simulate the solid particles – hydraulic oil separation, and Eulerian model is selected as the multiphase simulation model to simulate the hydraulic oil – water moisture separation. Simulation results demonstrate that the hydrocyclone separator can remove solid particles of 5 to 15 µm, while the rotating packed bed can mitigate water moisture. The results indicate that the developed Higee hydraulic oil purification device can provide an effective and efficient manner for controlling the contamination level of fluid power systems.

Modelling a throttling device during separation of moisture from gas flow

The need to design a model of a throttling device, which is used in the process of low temperature separation (LTS) of moisture from the gas flow, is predetermined by the necessity to coordinate the modes of functioning of the throttle with the modes of the heat exchanger and the separator that are included in the installation of separation. Proceeding from the task of efficient management of the process of the LTS of moisture from the gas flow, we analyzed a channel of control of the flow of gas under throttling. The peculiarity of managing the process of separation of moisture is in the contradiction between the productivity of the gas flow and the conditions of moisture removal. In order to study the influence of parameters of a throttle on the formation of the modes of passing flow, a distribution of the field of the flow velocities is obtained in the software environment of ANSYS Workbench. Visualization of the flow stream allows analyzing the level of turbulence of the flow under throttling and forecasting the trajectory of moisture droplets formed at throttling. By comparing the data obtained from the experimental installation with the data of numerical calculations, carried out in accordance with well­known mathematical models of the flow under throttling, we conducted the assessment of the adequacy of the description of the object of control. It is shown that the assumption of incompressibility of natural gas when evaluating the rate leads to significant errors. As a result of the identification of the parameters of a throttling device, its simulation was implemented in the environment of MatLab Simulink. Block construction of the model allows performing simulation under conditions of arbitrary nature of the change in the parameters of the process over time. The assessment of the adequacy of simulating a throttle device allows using the studied model for constructing a model of an installation of moisture separation from gas flow.

A thermo-economic analysis of repowering of a 250 MW coal fired power plant through integration of Molten Carbonate Fuel Cell with carbon capture

This paper presents a thermo-economic assessment of a repowering configuration of a 250MW old existing coal fired power plant through integration of Molten Carbonate Fuel Cells (MCFC) at the downstream of the existing boiler. Hydrogen-rich syngas generated from natural gas in an external reformer used as fuel in MCFC unit. In the downstream of MCFC the residual combustible species from anode side is burnt with 98% pure oxygen, followed by heat recovery, cooling and moisture separation, CO2 compression and storage. The proposed repowering scheme helps to increase the plant capacity by about 27%, while capturing 67% of emitted CO2. Contrary to the conventional CO2 capture process, this MCFC repowering does not eat up the plant's efficiency, rather, it increases the net efficiency by 1.1%-points. The effect of repowering on cost of electricity, CO2 avoided cost (CCA), specific primary energy consumption for CO2 avoided (SPECCA) are estimated. The study shows that this repowering scheme yields a lesser unit cost of electricity (COE) compared to the commercially available monoethanolamine (MEA) based carbon capture retrofit.

Study of Shell, Meat and Moisture Separation from Fresh Acetes

Study of Shell, Meat and Moisture Separation from Fresh Acetes

Residual moisture content and separation efficiency optimization in pilot-scale vibrating screen

Vibrating screening is still one of the main operations considering solid–solid and solid–liquid separation processes. Although it is an equipment of simple design and execution, the full description of a screening unit operation may be difficult to predict, considering that several operational variables can influence it. Therefore, the main objective of this work was to evaluate the best possible combination between the process variables screen aperture size, the volumetric concentration of solids in the feed, and the g-force (measurement of the vibration). This configuration predetermined values for moisture content of the retained material over the screen and separation efficiency regarding particle size. For this, a suspension of phosphate rock concentrate (with a particle density of 3.25g/cm3 and average particle size of 95μm) was diluted in water to perform the experiments in a pilot-scale vibrating screen. The results were analyzed statistically and correlations for each response were fit. The highest values of separation efficiency were found with the lowest values of cut-size diameter, which is desirable in terms of separation. A multi-objective optimization in the experimental range was developed, finding the optimal point for the moisture content of 17.29% and the separation efficiency of 86.88%. The effects of screen aperture size and g-force had important roles in this study.

F214 湿分分離性能向上のための液滴径粗大化機構に関する研究(OS9 熱・流動(4))

The moisture separator reheater (MSR) is a facility which is used to improve the thermal efficiency for the nuclear power plant. We have been developing the technique to improve moisture separation efficiency of MSR using wire-mesh combined with wave-shaped vanes. The goal of this study is to clarify the wire-mesh configurations which can minimize the exit moisture by droplet diameter measurement under a dispersed flow condition which was made by air and water from a spray nozzle. The results showed that droplet diameters were increased as the number of layer was increased. Within our experiment range, the wire-mesh configuration which has more than three layers yields the increase of the droplet diameter. Besides, although the increasing flow velocity caused generation of small droplets, it was indicated that the velocity range which keeps droplets coarse, can expand using means of increasing layer of the mesh.

1028 ワイヤメッシュ積層構造による微小液滴除去手法の開発

The moisture separator reheater (MSR) is a facility which is used to improve the thermal efficiency for the nuclear power plant. We have been developing the technique to improve moisture separation efficiency of MSR using wire-mesh combined with wave-shaped vanes. The objective of this study is to clarify the wire-mesh configurations which can minimize the exit moisture by droplet diameter measurement. We confirmed that droplet diameters were increased and the exit moisture was reduced as the number of layer was increased. Within our experiment range, six layered wire-mesh with 0.65 mm diameter can minimize the moisture, which is reduced from 0.45% without wire-mesh to 0.08%.

Optimization of Intensification of Freeze-Drying Rate of Banana: Combined Applications of IR Radiation and Cryogenic Freezing

A programmed experimental study on infrared (IR) aided freeze-drying of cryogenically (LN2) frozen heat sensitive material viz. banana (Musa acuminata) rendered faster moisture separation rate compared to the conventionally frozen samples. Response surface methodology (RSM) could determine the simultaneous optimal freeze-drying conditions of 59.78°C IR temperature, 10 mm sample thickness, and 5 h drying time corresponding to the minimum moisture content of 4.11%, lowest final product temperature of 22.799°C, and maximum rehydration ratio of 1.72. Color difference, shrinkage, microstructure, pH, wettability, polysaccharide, and mineral contents of the cryogenically frozen freeze-dried banana at the optimal conditions have been determined coupled with Fourier Transform Infrared Spectroscopy (FTIR) and Carbon Hydrogen Nitrogen Sulfur (CHNS) analyses. Freeze-drying kinetics at optimal conditions have been evaluated and compared with literature published models and the “Handerson and Pabis” model was found to characterize the present case most closely among all drying models. A novel method for intensification of moisture separation rate leading to freeze-dried banana with high quality could thus be explored.

向流接触式デシカント空調システムの除湿性能(第14回動力・エネルギー技術シンポジウム)

Conventional air conditioning consumes huge amount of energy to remove latent heat during hot and humid summer in Japan. Desiccant air conditioning is able to remove moisture directly and the system is able to utilize waste heat for drying of the desiccant, thus, low temperature heat is applicable to the separation process. Counter current flow as well as parallel current flow is applied for air-desiccant contact system to improve applicability of waste heat and rate of moisture separation. Their performance are confirmed by the simulation based on the fundamental experiment to determine the mass transfer coefficient and continuous dehumidification.

C206 向流接触式デシカント空調システムの除湿性能(OS4 省エネルギー・小型分散電源・コジェネ技術)

Air conditioning consumes huge amount of energy to remove latent heat during hot and humid summer in Japan. Desiccant air conditioning is able to remove moisture directly and the system is able to utilize waste heat for drying of the desiccant, thus, low temperature heat is applied to separation process. Counter current flow as well as parallel current flow is applied for air-desiccant contact system to improve applicability of waste heat and rate of moisture separation. Their performance are confirmed by the simulation based on the fundamental experiment to determine the mass transfer coefficient and continuous dehumidification.

FERMENTATION AND CHEMICAL ACIDIFICATION OF SALAMI‐TYPE PRODUCTS – EFFECT ON YIELD, TEXTURE AND MICROSTRUCTURE

ABSTRACT The effects of using lactic acid bacteria (LAB), liquid lactic acid and encapsulated acids (lactic, citric and glucono‐delta‐lactone [GDL]) to reduce the pH of salami‐type products were investigated. Liquid lactic acid caused an immediate pH drop, crumbling of meat particles and some moisture separation. This type of precooking protein denaturation resulted in the lowest springiness value and showed a microstructure with gaps among the cooked meat particles. The encapsulated acids did not produce such problems, and their effects on cook loss and hardness values varied. The nonacidified control (pH 5.60) provided the highest hardness value and low cook loss, because of less disruption to protein gelation during cooking. The slow acid release, during the overnight LAB fermentation, resulted in some binding prior to cooking, but a higher cook loss compared to the encapsulated acids.

Granular Composition of Self-Packing Mixtures and Its Role in the Removal of the Solid Phase During Moisture Separation

The process of self-packing of mineral-polystyrene mixtures within the closed space of a perforated mold is considered. A model for liquid filtration in a porous medium is proposed. To prevent removal of the solid phase from the mixture by the liquid flow during filtration, the volume of fine-grained fractions should roughly be 0.3 the volume of coarse-grained fraction.

IMPORTANCE OF FAT EMULSIFICATION AND PROTEIN MATRIX CHARACTERISTICS IN MEAT BATTER STABILITY

ABSTRACTFinely comminuted meat products are a mixture of proteins, fat particles, water, salt and often carbohydrates. During preparation of the raw meat batter, fat is chopped into tiny particles which are thoroughly mixed within the comminuted lean meat. During cooking, the challenge is to minimize/prevent fat and moisture separation from the product. During the past 3–4 decades two major, but differently oriented, research thrusts have been presented to explain the mechanism(s) by which meat batters are stabilized. They include the emulsion theory and the physical entrapment theory. The first emphasizes the importance of fat emulsification (i.e., forming an interfacial protein film around the fat globules) whereas the physical entrapment theory stresses the importance of the protein matrix in binding the fat. The exact mechanism by which finely comminuted meat batters are stabilized is still uncertain. In this review arguments presented to support both research thrusts are discussed.