JPS58500936A - Twin-stage flash evaporator with improved distillate collection - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Description of Applications Related to Opposite Flash Evaporators with Improved Distillate Collection R, I!, Ba1lie ) As a continuation of the application filed by K and handed over to an important recipient, I de 10 years 7 U.S. Patent Application No. 76, ttS, filed on March 3, ``Multi-Stage Flash Evaporator'' Design” 0 Background of the invention The present invention relates to a water desalination plant, in which the stages used in 4IK and 5 plants are paired. This is a paired flash evaporator KII. Ru.

In a multi-stage flash evaporation water desalination plant, brine passes through multiple evaporation stages at progressively higher pressures. They flow through one after another with decreasing power. In each evaporation stage, the water becomes vapor and goes to the condensation stage. The "unit" used here condenses on the condensation tube and falls into the collection pan. The term "" shall also mean the parts of each multi-stage evaporator vessel combined into a single tube bundle. A typical long flow for a multi-stage flash evaporator unit is w) In the design, the brine extends from evaporator stage to evaporator stage and across the ends of the evaporator unit. flow parallel to the direction of the condensing tube. For example, each unit has multiple stages of 6 to t. A common partition separates each stage of the evaporation chamber and condensation chamber (J). ms from the next stage evaporation chamber and condensation chamber.Each long flow chamber has a pair of An end tube plate and a pair of wooden boxes are required. Although the total number of end tube plates and wooden boxes required for long am can be eliminated, K: s-leek) Maintenance costs are reduced due to the use of a long condensing pipe that spans 6 or more stages. There are some disadvantages. Due to its nature, Choryuyu is suitable for small-capacity plants (for example, JOf10,000Ga). (up to 10 million gallons/day) and very large capacity plants (e.g., more than 10 million gallons/day) above) and is also economical to manufacture and operate. The cross-flow type is also one of the commonly used multi-stage seven-lush evaporator systems. ten In the diagonal type, each stage is equipped with a pair of wooden boxes and a pair of end tube plates. The condensing tube is The end tubes are combined into a single evaporation chamber between the plates, and the salt water flows through the condensing tube in the evaporation chamber. flows in the cross direction. In this configuration, each unit typically has a single stage. Since it is a common unit, there are no internal partitions to separate the stages within each unit. partitions are obtained by separating stages between units.

According to the cross-flow type, the condensing pipes in each unit are relatively short, making plant operation easy. It is economical to operate, but requires a large number of units. One end tube plate for each unit The manufacturing cost is quite high because two water boxes are required.The conventional cross-flow type These are usually economical in large capacity plants (e.g. 100,000 to 6,000,000 gallons/day). Mono de (J) Ru0 A recent improved evaporator unit is called a membrane cross-flow unit, and the patent application mentioned above It is described in. In a membrane cross-flow unit, a pair of evaporation stages and a pair of condensation stages are used. and two evaporation chambers in one adjacent evaporation stage are provided in a single cross-flow unit. The two condensing chambers are separated by a single partition extending Km parallel to the tube axis; It is separated by another partition extending at right angles to Km. Evaporation chamber and condensation chamber on the same stage There is communication between [5K] so that steam can flow, condense, and collect distillate. . Similar to long-flow type in that the condensing tube passes through two condensing chambers within a single evaporator unit. It is a cross-flow type Km in that the salt water flows not in the longitudinal direction but in the lateral direction of the condensing pipe. ing.

In conventional cross-flow type membrane evaporators, one evaporator unit has one stage of flashing. While only evaporation and condensation are performed in a single evaporator unit, two Seven stages of evaporation and condensation are performed. For this reason, the membrane-tight evaporator vessel is Traditional cross-flow evaporator with generally improved efficiency, shorter and lighter weight, and the same number of stages It can be the same width or only slightly larger than the container. Anti-membrane evaporation The evaporator plant consists of adjacent evaporator units whose tube bundles are connected by crossover piping. The plant area is normally 20% to 25% smaller. subordinate The next type of desalination plant will connect Koda's evaporator units in series with crossover piping. Subsequently, there is also a one-stage evaporator configured.According to the 0-to-stage WK, the evaporator stage is one stage. The number of evaporator units required to It is possible to produce the same amount of excavated material as the two conventional cross-flow type units.

Shooting type reduces requirements on tubesheets and water boxes and improves plant operability. performance, maintenance costs are low, and pump energy costs are low (zero single row pump). If it is a runt, the initial cost will be low and the total saltwater treatment capacity will be high.

In a conventional cross-flow multi-stage flash evaporator, each stage produces 7 liters of evaporated vapor. The air passes through a screen separator and condenses on the same stage of tubes. The generated bargains are accumulated It is cascaded from stage to stage in the duct, with the lowest temperature exiting.

In a typical conventional type, a step-to-step excavation cascade is formed on the end wall of the evaporator vessel. by using a collection duct at one end of the condensing tube bundle (i.e. at one end of the condensing tube bundle). In order to apply this configuration to a double-membrane type cross-flow evaporator, it is necessary to ducting is required (one duct at each end of the condenser tube bundle) versus a conventional trap in a membrane evaporator. Using a collection duct has the following drawbacks.

l The cascade distillate is flash evaporated in a second stage downstream of the stage where it is collected. At low cycle thermal efficiency (the heat recovered in the recirculation condenser is reduced).

Since one collection duct is used, the price of the evaporator container is high and it is difficult to install each one in a series. The flash evaporator unit runs along the bottom of the vessel, with longitudinal partitions. Thus, a long vessel having a pair of separated long evaporation chambers is provided. The container is further , by means of a horizontal stage partition installed at the top [also has a pair of separated condensing chambers]. From one evaporation chamber to one condensation chamber of the stage consisting of ~・ru〇, and the other evaporation chamber of the other stage. A device including a liquid separator is provided for introducing vapor from the ignition chamber to the other condensing chamber. It is.

The excavations from the condensing tubes are collected by respective tray devices under the tube bundles in each condensing chamber. It will be done. The collection duct system consists of a series of evaporators below the tray system near the transverse stage partitions. Economically located Km beyond the instrument tool F, this position is The end inlet provides maintenance access and full access to the evaporation chamber. This is the position to move. The collection duct device accumulates excavated material from stage to stage and cascades. The structure is configured such that the excavated material is efficiently collected at the next stage after the stage in which the excavated material was collected. There is a 5K that can be used for rush evaporation.

Brief description of the drawing FIG. 1 shows a long pipe constructed according to the principles of the invention with a central collection duct. Perspective view of the rush evaporator system, Figure 2 shows the condensation chamber of the two cold stages in the unit. (6) of the unit showing steam flowing from the flash evaporation chamber. cross section, Figure 3 shows the condensing tube bundle and vapor flowing over it through a liquid separation network at each stage and entering the condensing chamber. A partially cutaway plan view showing the situation, the second figure is the evaporator of a plant consisting of many units. Crossing the unit 1: Partial schematic diagram of the collecting duct that extends, Figure 3 is the line V-V of Figure DA. Viewed along K, the collection duct is partitioned and configured to separate stages and collect excavated material. A cross-sectional view showing that FIG. 6 is a sectional view taken along line W-Vl in FIG. S. Description of preferred embodiment Figures 1 to 4 show 11! of seawater, etc. Multi-stage flash evaporator brush to process liquid An anti-film evaporator unit 10 is shown. Get the plant desalination efficiency you need For this purpose, a plurality or a series of interconnected anti-film evaporator units IO are used. Yes Each membrane evaporator unit io has a long vessel tS, the vessel lj extending over its entire length at its bottom. It extends over to form separate flash evaporation chambers /l and /j. upstream The evaporation chamber/l operates at high temperature and high pressure, and the downstream evaporation mis operates at low temperature and low pressure. capacity The vessel has an upstream wall, a longitudinal interstage evaporation stage partition, and a bottom wall. Fri, side Ij! Both of these have a container/S, an evaporation chamber//and and extends over the entire length of /J. The longitudinal partition Dada is a container/II) g; , is vertically divided into two long evaporation ml/ and /J.

(7) In the illustrated example, the roof 11/4, which is also preferably sloping and has a top, is ) between the end wall that closes the end, that is, the end plate it and ko0 and the side wall koko and 1 Covering 0 flat bottom wall J (connected as the bottom wall of the adjacent module evaporator unit) (continuing) completed the structure that constitutes the approximately rectangular container, and the container is flat. Alternatively, it is desirable to have a roof that slopes longitudinally and has a peak at the center.

The modules are then assembled at the plant construction site, with double walls between adjacent units. Instead, one can simply obtain a single (i.e. sidewall/J) series evaporator unit. .

The longitudinal walls /J, #3 and / are a series of salts running the entire length of the container /S. It ends above the bottom wall by a distance so as to form a water flow opening loco J. da The rubber member roller protrudes upward from the bottom wall near the downstream side of the salt water flow. flows over the dam member rollers and is exposed to more water in the evaporation chambers ii, i, and y. Let it evaporate to a certain amount.

A horizontal baffle core extends from the wall to above the dam member 6 inside the high temperature evaporation chamber. It protrudes forward and extends slightly beyond the first dam member, with a small amount of salt water flowing upward. 5 to 1 into the steam stream. It is.

In the illustrated example, a single & reduced pipe bundle JO with a substantially circular cross section is installed in the upper space under the roof/number. Inside the container 1, there is a horizontal stage partition or partition wall that extends along the entire length of the container 1. It is preferably provided approximately in the center between the two end plates /1 and 20, and is located at the top of the container /1. This serves to laterally divide the condensing chamber into two separate condensing chambers. tube The conduit of the bundle JO passes through the partition wall JJ in a sealing manner.

The condensing chamber J- receives the evaporated solution or vapor from the upstream evaporation chamber l/ The 0 Sierra de JS, which is separated from the downstream evaporation chamber/J by a loud J. Between the cut wall J and the end wall it extend along the pipe bundle to form the roof/block and the bottom of the condensing chamber J. One side of the tube bundle is substantially covered between the tube bundle and the distillate collection tray Jg. Similarly, A loudspeaker separates the condensing chamber J6 from the upstream evaporator WLII.

In summary, the condensing chambers Jl and J4 are separated by horizontal partition walls J and trays Jt. divided into one separate condensing stage and sealed by tubes Jj and 37. . Each condensation chamber receives steam from the evaporation chamber below it.

A long horizontal mesh or mesh separator #0 preferably covers the entire length of the evaporation chamber l/ The walls and tops are fixed with appropriate brackets (not shown), etc. It is supported on the leg Jta of the ray 3t. In the screen separator 〇, the steam is transferred to the evaporation chamber l/ From the condensing chamber 3 to the condensing chamber, which contains substantially salt water droplets, can also flow. It is. A similar mesh separator I is supported by side walls/separators and legs Jtb. It is installed over the entire length of the chamber/J and allows steam to be introduced from the evaporation chamber 13 to the three condensation chambers. The details of the structure and operation of the Ushizu O-net separators 〇 and 〇 are the same as in this application. Sometimes Die Moen and Earl Biederlin special publication 1986-50O93G ( 4) ``Opposite Flash Evaporation with Improved Geometry'' filed by and assigned to the same assignee. It is listed in ``Vessel''. This application includes alternative configurations of tube bundles and non-condensate removal structures. Another configuration is also described. Both ends of the condensing tube are received in the tubesheet, and the tubesheet is secured to the outer surface of the end wall it and coo. A high temperature water box (not shown) is attached to the end plate, and the end plate is close to the high temperature water box (not shown). A low-temperature water box (not shown) is installed to supply refrigerant to the condenser tube, as is well known. The distillate collection tray 3t is long (to collect distillate from the condensing pipe). It is roughly U-shaped. The tray 31 is provided below the tube bundle JO, Separate tray portions Jla and The four parts Jta and Jib having Jta and Jib are located at the bottom of the partition wall J[(K Therefore, it is separated into stages. Standing leg J of tray 3g? a and? Fb is It is laterally spaced from the long sidewall 12 and the lumber. Tray 31 in evaporation chamber/J The bottom part 9 also functions as a water droplet prevention baffle, similar to the baffle core of the evaporation chamber/l. To some extent.

To summarize the schematic operation of the evaporator unit, the brine extends the entire length of the vessel ( i.e. perpendicular to the direction of brine flow) through a series of brine flows - Rococo to the high temperature of the first upstream stream ( HT) flows into the flash evaporation stage. The vapor flash-evaporated in the high-temperature evaporation chamber is Salt water droplets are removed before the steam passes through the second line separator and enters the condensing chamber. steaming Qi is 1 and tubule (10) It condenses on the heat transfer surface to become a distillate and is collected in the distillate collection tray Jt. non-condensing The gas is discharged to the next evaporation stage through the discharge port St.

This process is basically repeated in the second low-temperature evaporation stage, so that the steam is The flow passes through a screen separator in the starting stage [and other parts of the two-stage condenser tube bundle are provided]. into the condensing chamber 74. Non-condensable steam in the condensing chamber JA is discharged into the enclosed tube bundle section. The steam that does not condense there is discharged to the outside through the conduit LD.

The exposed matter is a common collection duct)! It is stored in D, and the duct is evaporating a: the center of L knit. It runs across the line to accumulate distillate from successive units (see Figure #).

Collected from the tray section Jta and the pipe sections of the ytbK condensing chambers Jda and J6. The distillate flows towards the central transverse stage partition of the evaporator unit (10). No. As shown in Figure 3 and Figure 3, the collection duct 717 is constructed by the side wall of the container and the tray JK. The tray JK is supported by the tray JK and extends horizontally below the tray JK.

Each tray section Jta, Jtbl/C has a collecting duct go which collects distillate from the tray section. The σ-th j is provided with an appropriate opening lock 0 or 7/ for dropping the PC! li! As shown in IK (the interior of the collection duct!0 is separated into stages, and the distillate in each stage is It is partitioned so that it can be cascaded to the next stage.

This example duct to%! 0 has a substantially rectangular cross-sectional shape.

The stage of each evaporator unit IO is dimensioned appropriately from the stage of the adjacent evaporator unit 10. (II and height) separated by a partition 72 with an oriice 7 da. The accumulated debris is transferred to the high pressure stage of the unit 10 while maintaining stage separation. You can skate 5K.

In addition, the duct j0 has an orifice t included in each evaporator unit lo. A partition number 7 is provided which is configured to separate the paired stages. instructor In this case, partition No. 7 works together with partition No. 7 to connect the F-ray Jt of each evaporator unit. A high pressure duct 741to is formed through which the distillate falls from a.

In chamber 10-/[, the next highest evaporator unit 10 passes through Orice The distillate received from the tray is accumulated with another distillate from the tray opening rod 0-/. As shown, the oriice γg-/, which has a limited height like other duct oriices, to another chamber of the low pressure stage of the same unit in which flash evaporation occurs. flows. Pass through the opening l-1 from the tray part Jlb of the low pressure stage of the same unit 10. The exudate that falls is added to the detected exudate in chamber 12-/. What will happen next Km? It flows downstream through the orifice to the chamber go-co below the tray part Jfa. Therefore, 7 lashes of steaming are carried out in the high pressure stage of the next stage, that is, the next lowest stage of the plant, unit io. emanate. The distillate is collected and accumulated in stages throughout the plant as described above. .

As shown by the broken line arrow in Figure 6, 7 lashes of distillate are evaporated from the distillate to the next higher stage and then to the chamber 10. -/IIc The steam entering is when the tray is opened (/2) K11i as well as 0 rising through the lot 0-/ into the condensing chamber Jda! Steam from tJ-/ rises through the tray opening f/-/ and condenses in the condensation chamber J6. In the operation of this type of membrane evaporator structure, User efficiency and overall performance are improved, and economics are also improved. Also Since the distillate is evaporated at each stage, the thermal efficiency of the knife is high. ◎ Furthermore, the generated feature has one center point instead of the two data points that were previously required. cascading from stage to stage, reducing the cost of the evaporator vessel. It is easier to maintain since it can be accessed from the entrance at either end of the 1 Hunting Whisper 8-500936 (5) IG 2 international search report

Claims (1)

[Claims] t Evaporate the solvent from S* (a series of evaporation stages are operated at progressively lower pressures). A multi-stage 7-stage shoulder generator for a multi-stage flash evaporation plant, with opposing It has an end wall, a long side wall, a top wall, and a bottom wall, and has a bottom wall where the solvent evaporates. a generally elongated enclosure having an upper portion in which the parts and writings are condensed; A device that divides the upper part of the enclosure to create a pair of separate condensation chambers arranged in steps in the longitudinal direction. , The holes of the dividing device are passed through the holes of the dividing device so as to form a refrigerant flow in the longitudinal direction between the end walls KW. a condensing device with a play of long heat exchange tubes, A device for collecting the effluent from the condensation chamber is separated from the lower part of the enclosure. , an apparatus forming a pair of separate evaporation chambers in which the solution is directed across the enclosure; The condensation chamber is separated from the evaporation chamber and the evaporated solvent is collected in a high pressure evaporation stage. One evaporation chamber leads to one condensation chamber, and in the next low pressure evaporation stage, the other evaporation chamber a device for guiding the condensing chamber from the condensing chamber to the other condensing chamber; A tray that is combined with each of the condensing chambers and collects written material and guides it toward the dividing device K. a device; The tray extends Km in the lateral direction, is supported substantially below the dividing device, and is coupled to the tray device. ``Receive the CC output and condense the evaporated steam through the above tray device. A duct device for moving the room into the room; (l Dano partitioning the duct system into a high pressure chamber and a low pressure chamber, each of which is combined with the condensing chamber; and a device for guiding written materials from the high-pressure duct room to the low-pressure duct room. Tsushiko evaporator unit. The above partition device is assembled from the high-stage evaporator unit to the high-pressure condensing chamber. into the combined high-pressure duct chamber (with oriice, The partition device guides the written material from the one duct chamber to the other low-pressure duct chamber. The first oriice and the materials are transported from the other duct room to the next lower evaporator unit. and a third oriice for guiding the multi-stage 72 to the Technical evaporator unit @3 Each of the above tray devices is supported below the above pipe, and the above A long tray extends between the splitting device and the end wall and forms the bottom of the condensing chamber, and each A claim in which the tray device has an opening for guiding the writings downward to the duct device. Range of multi-stage flash evaporator described in item 1 above each evaporator unit The duct system is connected to the duct system of the upstream and downstream feeding evaporator units in contact with ILK. In order for the writing to be accumulated from one unit to the next, A multi-stage flash having a plurality of multi-stage evaporator units according to item 7 evaporator plant. The above partition device condenses the written material from the next higher stage evaporation unit A at high pressure i! to It has an orifice leading to the combined high pressure duct chamber, The partition device guides the distillate from the one duct chamber to the other low pressure duct chamber ( The first oriice and the distillate are transported from the other duct chamber to the next lower evaporator unit. The multi-stage brush according to claim 1, having an orifice of <tgs leading to the Que evaporator plant. Special table 1986-500936 (2)