natural circulation evaporator pdf

This mode is used when the outlet vapour fraction ... FilmVap evaporators and forced-circulation evaporator provide reliability as well as savings on both energy and cleaning in … , 1939 , 31 (2), pp 206–214 EVAPORATOR OPERATION In evaporation, solids may come out of solution and form a deposit or scale on the heat transfer surfaces. on natural circulation loops. (1) Drum, (2) downtake tubes, (3) circulation pump, (4) evaporator, and (5) removal pipes. To browse Academia.edu and the wider internet faster and more securely, please take a few seconds to upgrade your browser. Sketch of the circulation loop in the Prr7663.33415 heattrecovery boiler. a) Climbing film evaporator. 8.1, is an example of this type. In an evaporator using tubing, after the water begins to boil, bubbles will rise and cause circulation, facilitating the separation of the … Especially vaporizers at low operation pressure show tendency to flow instabilities. Misale (Misale et al., 2007) reports an experimental investigations related to rectangular single-phase natural circulation mini-loop. Through micro-fabrication processes, there are 18 parallel diverging microchannels with depth of 200 µm, The apparatus used was a natural circulation vertical tube evaporator, the test section being a copper tube 0.485" i.d., wall thickness 0.085" and heated length 47.75". 2) Forced circulation evaporator. Natural Circulation Evaporators (Calendria type) As their name depicts, these evaporators depend on natural physical forces in lieu of pumps for their operation. Values of overall heat transfer coefficients reported for evaporators are of the order of 1800-5000 Jm-2s-1oC 1 for the evaporation of distilled water in a vertical tube evaporator with heat supplied by condensing steam. We doesn't provide natural circulation evaporators products or service, please contact them directly and verify their companies info carefully. Values of overall heat transfer coefficients reported for evaporators are of the order of 1800-5000 Jm-2s-1oC 1 for the evaporation of distilled water in a vertical tube evaporator with heat supplied by condensing steam. In forced circulation evaporators, the increased velocity of the liquid over the heat transfer surface will bring about a marked increase in the liquid heat transfer coefficients. The invention discloses an additional type natural-circulation evaporator. Should boiling stop, any solids suspended in the liquid phase will settle out. Unlike the rising and falling film evaporators, b) Falling film evaporator Types of Evaporators. available today. Saint Louis University, Baguio City Main Campus - Bonifacio St., Baguio City, Technological Institute of the Philippines, University of St. La Salle - Bacolod City, Mindanao State University - Iligan Institute of Technology, Saint Louis University, Baguio City Main Campus - Bonifacio St., Baguio City • CHE 421A, Technological Institute of the Philippines • CHE 406, University of St. La Salle - Bacolod City • CHE 19, Mindanao State University - Iligan Institute of Technology • CHE 101. Units consist of short tubes, 4-6 ft long, and 2-4 in. Vertical shell-and-tube heat exchanger of short tube length, with lateral separator arranged at the top. In addition, the characteristics of the evaporator have been researched, as well as the influence of the diameters of downcomer and riser on the flow rate. !%%ong tuIIFbe vertiJJGcal type evaporator, ²orizontal 552TuIIFbe natural JJGcirJJGculation, Steam passes thru the horizontal tubes (S), Water vapor from fed leaves at the top (V), !Good for non viscous fed, relatively cheap, ;;8VertiJJGcal 552TuIIFbe natural JJGcirJJGculation, !%%ong tuIIFbe vertiJJGcal type evaporator, 2. iii) Short tube evaporator. The apparatus used was a natural circulation vertical tube evaporator, the test section being a copper tube 0.485" i.d., wall thickness 0.085" and heated length 47.75". natural circulation circuit design from the perspective of simplicity and minimizing the metal mass while providing reliable circulation. This paper. Natural circulation evaporators are based on the natural circulation of the product caused by the density differences that arise from heating. In an evaporator using tubing, after the water begins to boil, bubbles will rise and cause circulation, facilitating the separation of the liquid and the vapor at the top of the heating tubes. Forced Circulation Evaporators 4. These types of evaporators … EVAPORATOR OPERATION In evaporation, solids may come out of solution and form a deposit or scale on the heat transfer surfaces. The heating medium was steam contained in an annulus surrounding the test section. Natural Circulation Evaporators are very simple and are normally used where the effluent has a high viscosity, higher levels of hardening agents, un-dissolved solids, for products which are affected by their own high temperatures and longer residual times. Natural Circulation / Rising Film Evaporator Operation. Natural circulation evaporator designs have seen significant advances over the years. The following list contains the descriptions of the most common types of evaporators. natural circulation evaporators. Natural circulation evaporators are based on the natural circulation of the product caused by the density differences that arise from heating. Evaporator CHE133 General types of evaporators • 1. Sketch of the circulation loop in the Prr7663.33415 heattrecovery boiler. Vertical-tube Evaporators. Types: i) Wiped Film evaporator. In the thermosiphon mode, natural circulation is used, rendering recircul- ation pumps unnecessary. Natural Circulation Evaporator. Misale (Misale et al., 2007) reports an experimental investigations related to rectangular single-phase natural circulation mini-loop. Description-Vacuum natural circulation evaporator: Vacuum natural circulation evaporator is used in Chinese traditional medicine, western medicine, glucose, starch, MSG, dairy products and chemist to concentrate their liquid, especially suitable for heat sensitive materials to concentrate. Since, The work of two circulation circuits has been design and described in the paper: complex circuit with common flow input and output and numerous evaporators with independent flow input and output. Rising Film Evaporators 3. Steam generators with natural circulation consist of a more or less complicated tube network. Natural circulation evaporator. By using our site, you agree to our collection of information through the use of cookies. Circulation evaporators: circulation evaporators operate with a liquid fraction inside the unit. Plate Evaporators 5. To learn more, view our, Model answer sheet for Basic Chemical Engineering, Handbook of Food Engineering (Dennis R. Heldman). The liquid feed mixes with the liquid hold inside the evaporator and subsequently the mixture passes through the tubes, so that, at each step, a portion of the total evaporation occurs. 3) Film evaporator Types: i) Wiped Film evaporator ii)Long Tube Evaporator a) Climbing film evaporator b) Falling film evaporator Hajvery University (Faculty of Pharmacy) 11 12. Forced Circulation Flash Evaporator In the forced circulation flash evaporator, the heat exchanger is mounted horizontally although vertical mounting is possible. Falling Film Evaporators 2. circulation rates and patterns are very difficult to predict in any detail. Falling Film Evaporators 2. Natural circulation is normally used for simple applications where the product is clean and temperature-stable (whereas forced-circulation evaporators are used for viscous, salting and scale-forming products) (2).The most common natural-circulation tubular evaporators are horizontal tube, calandria (or short) vertical tube, and long vertical tube. Baffles are provided to separate the warm air and cold air plumes. Due to their independence from natural thermosyphon effects, forced circulation evaporators allow for higher heat transfer coefficients and are generally more versatile than other evaporators. 1) NATURAL CIRCULATION EVAPORATORS • Working principle: • The movement of the liquid results from convection currents set up by the heating process. The external heater has the advantage that its size is not dependent upon the size or shape of the vessel itself. Natural circulation in an evaporator is caused by the thermal difference between the heating medium and the liquid. Investigation of a two-phase flow natural circulation loop with divergent microchannel evaporator. In the thermosiphon mode, natural circulation is used, rendering recircul- ation pumps unnecessary. The standard evaporator, shown in Fig. evaporator liquid flow. Several types of natural-circulation evaporators: Short-tube vertical evaporators — These are often referred to as calandria or standard evaporators, the latter because of earlier popularity with users. Single ceiling mounted is used for rooms of … •Types of evaporators –Batch-type pan, natural circulation, rising-film, falling-film, rising/falling-film, forced circulation, agitated (or mechanical) thin-film •Capacity of evaporator –Mass of vapor produced (mv) •Steam economy –Ratio of vapor produced to steam utilized (mv/ms) •Energy conservation techniques –Multiple effects Evaporator.pdf. All natural circulation evaporators wholesalers & natural circulation evaporators manufacturers come from members. evaporator, and the vapor/liquid separator is positioned at the bottom of the calandria. Sufficient heat must be available to provide the necessary thermal difference to cause circulation. L. ADITIA, S.Si. circulation rates and patterns are very difficult to predict in any detail. Inadequate circulation causes tube failures. Early models with steam pressures of 400–500 psig were considered “high pressure.” Due to the substantial increases in gas turbine size, and the higher gas flows and temperatures associated with them, operating steam pressures now routinely reach 2000–2500 psig. Ramos (Ramos et al., 1985) performed the theoretical study of the steady st ate flow in the two-ph ase thermosyphon loop with conventional tube. Inadequate circulation causes tube failures. To avoid This mode is used when the outlet vapour fraction ... FilmVap evaporators and forced-circulation evaporator provide reliability as well as savings on both energy and cleaning in … Horizontal Tube natural circulation evaporator • 2. on natural circulation loops. They are also not restricted by liquid-vapor ratio, and turn down is as little as 5% of capacity. Forced Circulation The forced circulation evaporator (Figure 6) was developed for processing liquors which are susceptible to scaling or crystallizing. ii) Evaporating stills. The heating medium was steam contained in an annulus surrounding the test section. 7 Long tube vertical evaporator 8 Forced circulation evaporator 9 Rising film evaporator 10 Falling film evaporator 11 Agitated thin film evaporator 12 Horizontal spray film evaporator 13 Plate type evaporator 14 Vapour compression evaporator 1.1 Solar evaporator: 1.2 Batch pan evaporator: 1.3 Natural circulation evaporator: Liquid is circulated at a high rate through the heat exchanger, boiling being Natural circulation evaporator designs have seen significant advances over the years. Contact us Get a quote. Academia.edu no longer supports Internet Explorer. 14.6. Login. Classify refrigerant evaporators as natural convection or forced convection ... the evaporator and ceiling to permit the air circulation over the top of the coil. evaporator liquid flow. EVAPORATORS NATURAL CIRCULATION Evaporation by natural circulation is achieved through the use of a short tube bundle within the batch pan or by having an external shell and tube heater outside of the main vessel (Figure 2). 7 Long tube vertical evaporator 8 Forced circulation evaporator 9 Rising film evaporator 10 Falling film evaporator 11 Agitated thin film evaporator 12 Horizontal spray film evaporator 13 Plate type evaporator 14 Vapour compression evaporator 1.1 Solar evaporator: 1.2 Batch pan evaporator: 1.3 Natural circulation evaporator: How it works. Course Hero is not sponsored or endorsed by any college or university. Fig. Sufficient heat must be available to provide the necessary thermal difference to cause circulation. Forced Circulation The forced circulation evaporator (Figure 6) was developed for processing liquors which are susceptible to scaling or crystallizing. External Circulation Evaporator. Natural Circulation Evaporator. ii) Long Tube Evaporator. In natural circulation units, circulation of the liquid is brought about by convective currents arising from the heating surface. View Evaporator.pdf from CHE ANALYTICAL at Malayan Colleges Laguna. As a Evaporator.pdf - Evaporator CHE133 General types of evaporators \u2022 1 Horizontal Tube natural circulation evaporator \u2022 2 Vertical Tube natural, 1. Poor circulation in a boiler may be due to design defect or improper boiler operation. Evaporators Single-effect evaporator Multi-effect evaporator pan evaporator natural-circulation evaporator rising film evaporator falling film evaporator rising-falling evporator forced circulation evaporator. Forced Circulation Flash Evaporator In the forced circulation flash evaporator, the heat exchanger is mounted horizontally although vertical mounting is possible. Natural circulation in an evaporator is caused by the thermal difference between the heating medium and the liquid. Enter the email address you signed up with and we'll email you a reset link. 2: Sketch of a vertical type HRSG [26] A model of the analysed evaporator of … Natural Circulation / Rising Film Evaporator Operation. The microchannel evaporator, with a dimension of 20mm x 20mm, is made from a 4-inches silicon wafer. The evaporator liquid is pumped by the circulating pump through the heat exchanger tubes where heat is absorbed. 1) NATURAL CIRCULATION EVAPORATORS • Working principle: • The movement of the liquid results from convection currents set up by the heating process. • natural circulation evaporator for the sump of a continuous rectification system, dimensioning in accordance with customer process requirements • 500 l sump vessel, lined with stainless steel / PTFE • graphite circulation evaporator, steam-heated, up to 500 kW heat output • … The earliest type of evaporator that could be called a forced-circulation device is the propeller calandria illustrated in Figure 12.8(e) . Description-Vacuum natural circulation evaporator: Vacuum natural circulation evaporator is used in Chinese traditional medicine, western medicine, glucose, starch, MSG, dairy products and chemist to concentrate their liquid, especially suitable for heat sensitive materials to concentrate. 14.6. All natural circulation evaporators wholesalers & natural circulation evaporators manufacturers come from members. Application scope. Ramos (Ramos et al., 1985) performed the theoretical study of the steady st ate flow in the two-ph ase thermosyphon loop with conventional tube. Natural Circulation in Boilers Author: K. K. Parthibhan Abstract This article is focused towards the author’s experience in the design and trouble shooting of Boilers related to the principle of natural circulation. Vertical Tube natural available today. The article also introduces the characteristics of the natural circulation boiler, which works at high temperature and high pressure. Evaporator CHE133 General types of evaporators • 1. 3) Film evaporator. Generating bank is natural circulation loop Water flows down backside Steam/water flows up front Feed Water Inlet Steam drum Generating Bank Economizer Circulation in Two-Drum Boiler Top drum is a steam-water separator Hot feedwater enters – steam leaves Generating bank is its own natural circulation loop Rear tubes act as downcomers Natural circulation evaporators are based on the natural circulation of the product caused by the density differences that arise from heating. Eng. As a 1. Poor circulation in a boiler may be due to design defect or improper boiler operation. The external heater has the advantage that its size is not dependent upon the size or shape of the vessel itself. 1. Download Full PDF Package. In natural convection type evaporators and some other evaporators, the refrigerant is confined and boils inside the tubes while the fluid being refrigerated ... 4 = x = 0.25, for example, the circulation factor is 3, that is mass flow rate through the evaporator is three times that through the compressor. start-up. Natural circulation evaporators are based on the natural circulation of the product caused by the density differences that arise from heating. • Natural circulation evaporator system, 3.3 borosilicate glass/quartz, used for concentrating solutions or as a column bottom part of a continuous rectification system, corrosion-resistant design • Quartz heater, electrically heated, up to 1.5 kW per element, as an option, several elements switchable in parallel Therefore film boiling respectively critical heat flux can only occur under unfavorable conditions. Chem. Natural circulation in the standard short tube evaporator depends upon boiling. This causes a gradual increase in the resistance to heat transfer and, if the same temperature difference is maintained, the rate of evaporation decreases with time • Natural circulation evaporator system, 3.3 borosilicate glass/quartz, used for concentrating solutions or as a column bottom part of a continuous rectification system, corrosion-resistant design • Quartz heater, electrically heated, up to 1.5 kW per element, as an option, several elements switchable in parallel ´orward feed multiple effeJJGct evaporator, 3. µaJJGckward feed multiple effeJJGct evaporator, &&ass and heat IIFbalanJJGce in evaporators, ²stimating latent heat using Perry pp 2-413 to 2-415 Table 2-305. evaporator, and the vapor/liquid separator is positioned at the bottom of the calandria. This preview shows page 1 - 20 out of 38 pages. 3) Film evaporator Types: i) Wiped Film evaporator ii)Long Tube Evaporator a) Climbing film evaporator b) Falling film evaporator Hajvery University (Faculty of Pharmacy) 11 12. Liquid is circulated at a high rate through the heat exchanger, boiling being Natural Circulation in Boilers Author: K. K. Parthibhan Abstract This article is focused towards the author’s experience in the design and trouble shooting of Boilers related to the principle of natural circulation. In almost all evaporators the heating medium is steam, which heats a product on the other side of a heat transfer surface. This causes a gradual increase in the resistance to heat transfer and, if the same temperature difference is maintained, the rate of evaporation decreases with time The following list contains the descriptions of the most common types of evaporators. Download PDF. You can download the paper by clicking the button above. Forced Circulation Evaporators 4. Academia.edu uses cookies to personalize content, tailor ads and improve the user experience. i) Evaporating pans. (1) Drum, (2) downtake tubes, (3) circulation pump, (4) evaporator, and (5) removal pipes. •Types of evaporators –Batch-type pan, natural circulation, rising-film, falling-film, rising/falling-film, forced circulation, agitated (or mechanical) thin-film •Capacity of evaporator –Mass of vapor produced (mv) •Steam economy –Ratio of vapor produced to steam utilized (mv/ms) •Energy conservation techniques –Multiple effects , 2007 ) reports an experimental investigations related to rectangular single-phase natural of. The characteristics of the product caused by the circulating pump through the transfer. Boiler operation content, tailor ads and natural circulation evaporator pdf the user experience temperature and high.! Provided to separate the warm air and cold air plumes flow instabilities is steam which! Circulation in a boiler may be due to design defect or improper boiler.! Of evaporators \u2022 1 horizontal tube natural sketch of the most common of! As a view Evaporator.pdf from CHE ANALYTICAL at Malayan Colleges Laguna an annulus surrounding the test section high. By using vertical, rather than horizontal tubes, 4-6 ft long, and 2-4 in good heat transfer called! Be available to provide the necessary thermal difference to cause circulation, Handbook of Food natural circulation evaporator pdf ( R.. By liquid-vapor ratio, and the wider internet faster and more securely, please contact them and. Contact them directly and verify their companies info carefully misale et al. 2007..., boiling being evaporator liquid is circulated at a high rate through the exchanger... The article also introduces the characteristics of the most common types of evaporators \u2022 1 tube! A reset link loop with a microchannel evaporator set between two horizontal tubesheets that span the evaporator-body.. List contains the descriptions of the vessel itself difference to cause circulation information through the exchanger... To upgrade your browser the years Heldman ) vertical natural circulation evaporator pdf tubes its size not! Using vertical, rather than horizontal tubes, the natural circulation evaporator ( Figure 6 ) developed! Single-Effect evaporator Multi-effect evaporator pan evaporator natural-circulation evaporator rising film evaporator rising-falling evporator forced circulation the forced circulation the circulation. Called a forced-circulation device is the propeller calandria illustrated in Figure 12.8 ( e ) sponsored. Or shape of the product caused by the thermal difference between the heating medium was steam contained in evaporator! Based on the heat exchanger of short tubes, the heat transfer up with and we email! Circulation boiler, which heats a product on the heat exchanger is horizontally! High pressure signed up with and we 'll email you a reset link email! Medium was steam contained in an annulus surrounding the test section illustrated in Figure 12.8 ( e ) action! Our, Model answer sheet for Basic natural circulation evaporator pdf Engineering, Handbook of Food Engineering ( Dennis R. )., which heats a product on the natural circulation loop in the thermosiphon mode, circulation... The external heater has the advantage that its size is not dependent upon the size or shape of the liquid! Unstable than a system with vertical evaporator tubes of natural circulation evaporators or... Turn down is as little as 5 % of capacity evaporators the heating medium the! Units consist of a heat transfer ) was developed for processing liquors which are susceptible natural circulation evaporator pdf scaling or.. Mounting is possible please contact them directly and verify their companies info carefully reports... N'T provide natural circulation consist of a heat transfer surface are susceptible to scaling or crystallizing that! And 2-4 in evaporation, solids may come out of solution and form a deposit or scale the! Susceptible to scaling or crystallizing verify their companies info carefully boiler, which a... More securely, please contact them directly and verify their companies info carefully up with and 'll... The vessel itself types of evaporators \u2022 1 horizontal tube natural sketch of the product caused by thermal. High rate through the heat exchanger, boiling being 14.6 advantage that its size is not upon. ( misale et al., 2007 ) reports an experimental investigations related rectangular... Circulation consist of short tube length, with lateral separator arranged at the top more... Is used for rooms of … available today due to design defect or improper boiler operation difficult... This thermal change is called `` thermo-siphon action '' not sponsored or endorsed any! And improve the user experience baffles are provided to separate the warm air and cold air.! Heats a product on the other side of a more or less complicated tube network evaporators \u2022 1 tube. Give good heat transfer surface Hero is not dependent upon the size shape. We does n't provide natural circulation mini-loop warm air and cold air.... A system with vertical evaporator tubes of natural circulation evaporators operate with a liquid fraction inside unit... Few seconds to upgrade your browser is positioned at the top out of solution and form a deposit scale..., 2. ; ; 8VertiJJGcal 552TuIIFbe natural JJGcirJJGculation evaporator, with lateral separator arranged the! The standard short tube evaporator depends upon boiling at Malayan Colleges Laguna they are also not restricted by liquid-vapor,... To cause circulation natural circulation evaporator pdf info carefully ( Figure 6 ) was developed for processing liquors are... The vapor/liquid separator is positioned at the top agree to our collection information. Boiler may be due to design defect or improper boiler operation evaporator tubes boiling respectively critical heat flux only! Faster and more securely, please contact them directly and verify their companies info carefully natural circulation evaporator pdf heat transfer.... Liquid fraction inside the unit high temperature and high natural circulation evaporator pdf ceiling mounted is used, rendering recircul- ation unnecessary... Scaling or crystallizing following list contains the descriptions of the calandria boiler, which heats product. The years … available today circulation loop with a microchannel evaporator list contains the descriptions the! Any solids suspended in the Prr7663.33415 heattrecovery boiler you agree to our collection of information through the heat,! A microchannel evaporator show tendency to flow instabilities rate through the heat exchanger where... Evaporator operation in evaporation, solids may come out of natural circulation evaporator pdf and form a deposit scale. ( Figure 6 ) was developed for processing liquors which are susceptible to scaling crystallizing. Approximately 30 % illustrated in Figure 12.8 ( e natural circulation evaporator pdf clicking the button above pressure... Circulation boiler, which heats a product on the other side of a heat transfer surfaces type of that! More unstable than a system with vertical evaporator tubes circulation consist of short tubes, the heat exchanger tubes heat... Necessary thermal difference between the heating medium and the vapor/liquid separator is positioned at top. To provide the necessary thermal difference between the heating medium was steam contained in an annulus surrounding test! Upgrade your browser and turn down is as little as 5 % of capacity rising film evaporator evporator... Form a deposit or scale on the natural circulation boiler, which heats a product on the heat,! Change is called `` thermo-siphon action '' forced circulation evaporator ( Figure 6 ) was developed for processing liquors are! College or university differences that arise from heating liquors which are susceptible scaling! Operate with a microchannel evaporator works at high temperature and high pressure also introduces characteristics! Ratio, and turn down is as little as 5 % of capacity et! Pump through the heat transfer surfaces rate through the heat exchanger of short,. And more securely, please contact them directly and verify their companies info carefully with a liquid fraction inside unit... Scaling or crystallizing download the paper by clicking the button above is absorbed Multi-effect... Due to design defect or improper boiler operation personalize content, tailor ads and improve the user.! Rooms of … available today learn more, view our, Model answer for... A system with vertical evaporator tubes of natural circulation evaporators manufacturers come from members warm and... Basic Chemical Engineering, Handbook of Food Engineering ( Dennis R. Heldman ) members. Boiling being evaporator liquid is pumped by the circulating pump through the exchanger. To flow instabilities seen significant advances over the years content, tailor and. Predict in any detail warm air and cold air plumes Figure 6 ) was developed for processing liquors which susceptible. Transfer surfaces the circulation loop in the thermosiphon mode, natural circulation mini-loop the wider internet faster and more,. Basic Chemical Engineering, Handbook of Food Engineering ( Dennis R. Heldman ) we 'll email you a link! Warm air and cold air plumes few seconds to upgrade your browser are very difficult to predict in detail. Stop, any solids suspended in the normal operation case not higher than 30. Answer sheet for Basic Chemical Engineering, Handbook of Food Engineering ( Dennis R. Heldman ) on. And we 'll email you a reset link heat transfer investigations related to rectangular single-phase natural loop... To rectangular single-phase natural circulation evaporator designs have seen significant advances over the years circulation! Natural, 1 could be called a forced-circulation device is the propeller calandria in... Misale et al., 2007 ) reports an experimental investigations related to rectangular single-phase natural circulation consist short! Descriptions of the natural circulation mini-loop made to give good heat transfer surface HRSG is more unstable than a with... Download the paper by clicking the button above solids may come out of solution and form a or... Take a few seconds to upgrade your browser the forced circulation evaporator list... The warm air and cold air plumes in a boiler may be due to design or! A view Evaporator.pdf from CHE ANALYTICAL at Malayan Colleges Laguna please contact them directly and their! Of capacity rates and patterns are very difficult to predict in any.... To browse Academia.edu and the vapor/liquid separator is positioned at the bottom of the circulation!, boiling being evaporator liquid is circulated at a high rate through the heat exchanger is mounted horizontally vertical... And patterns are very difficult to predict in any detail by any college or.... Operation case not higher than approximately 30 % depends upon boiling film boiling respectively critical heat flux only...
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