FI94217C - Liquid distributor for the membrane distiller and use of the distiller - Google Patents

Description

, 94217

The present invention relates to a liquid dispenser for a membrane distiller, consisting of a strip at the upper end of a bag-shaped distillate element to be spread on a film-coated outer material with parallel feeds.

10 A film distillate is a device consisting of flat bag-like elements placed against each other, which are a thin film material, such as a plastic film. Heat transfer takes place inside the elements from condensing steam through the membrane to the evaporating liquid flowing along the outer surfaces of the elements. Heating steam is the steam generated on the outer surfaces of the elements, which is fed through the compressor into the element-15 path to condense into a distillate obtained as the end product of the process.

Membrane distillates have typically been used to make fresh water from seawater, and have also been applied to the evaporation treatment of solids-containing suspensions.

20 FI publication 86961 discloses a distillate element of a membrane distiller, the upper end of which has a honeycomb end strip from which the liquid to be evaporated is fed to the outer surfaces of the element. The strip is provided with parallel, oblique supply channels starting at one end thereof, which communicate with the liquid container 25 on the side of the elements and which distribute the liquid to be evaporated over the entire width of the element surface. In addition to these liquid supply ducts, the strips also include steam ducts for the steam entering the elements pressurized by the compressor.

In parallel liquid supply channels of the list formed from the cell plate according to said known solution, which have the same width but different lengths, the pressure drop increases with the length of the channels when moving from the side of said liquid container side to the opposite side of the element. As a result, the spread of fluid in the transverse direction of the element is uneven, with the former side having shorter fluid passages receiving more fluid than the opposite side of the element to which the leading fluid passages are longer. In addition, when evaporating liquid suspensions containing solids, parallel, starting from the tank; the feed channels have proven to be easily clogged.

The object of the present invention is to provide a strip-like liquid distributor with parallel feed channels of a film distiller, in which said drawbacks of the known solution are avoided. The invention is characterized in that the strip at the upper end of the distillate element comprises a main transverse main channel from which parallel feed channels leading to the surface of the element 5 branch.

In the solution according to the invention, the main channel can be formed substantially wider than the branch supply channels of substantially the same length, the main channel evenly distributing to the supply channels a liquid which spreads on the surface of the element in its transverse direction in a substantially flat front. In addition, it has been found that the turbulence produced in the main channel can prevent the blockage of the supply channels, which makes the solution particularly suitable for the evaporation treatment of liquid suspensions containing solid particles.

According to a particularly preferred embodiment of the invention, the main channel is guided through the strip so as to divide part of the liquid flow into the supply channels as the remainder leaves the outlet end of the main channel. When treating solids-containing liquid suspensions, the turbulence generated in the main channel fluid flow has been found to hold the solid particles primarily in the main channel flow, where they end up at the outlet end of the channel without entering the membrane surfaces of the distillate elements through feed channels. Only the liquid phase separates mainly into the supply channels and on the surfaces of the elements. In addition to keeping the supply channels open, the advantage is that the need to clean the elements is reduced.

25 The above is facilitated if the main channel is substantially evenly wide and gently directed downwards and the supply channels branch from the main channel to the rear slope.

In view of the uniform distribution of the liquid to be evaporated, the list forming the liquid distributor is preferably constructed to comprise two main channels located in different halves of the element and the supply channels branching from each main channel toward the vertical center line of the element. The inlet and outlet ends of the main ducts can then be located at opposite ends of the strip, each main duct making a bend of about 180 ° near the center line of the element, the feed ducts branching from the main duct in the section between said bend and the main duct outlet end 35. By means of a bend in the main channel before the branches of the supply channels, the flow flowing in the main channel is effectively turbulent,; and the orientation of the supply channels ensures that there is no liquid-free dead zone in the middle of the element.

3,94217

It is advantageous to connect the liquid distributor according to the invention to the bag-like distillate element as an end strip integral thereto. As is known per se, the list can also comprise steam channels leading into the element. On the other hand, it is possible that the strip-like liquid distributor according to the invention forms a separate element in the membrane distiller, separate from the bag-like distillate elements.

The invention also relates to the use of a film distiller equipped with the liquid dispensers according to the invention described above for the evaporation treatment of a liquid suspension containing solid particles and in particular a fibrous suspension, such as cellulose cooking waste liquor. Reference is made to claims 9 and 10 for these applications.

The invention will now be described in more detail by way of example with reference to the accompanying drawing, in which Figure 1 shows the upper end of a bag distillate bag-like distillate element with liquid divider strips seen from the front and Figure 2 shows the upper ends of two adjacent distillate elements with liquid divider sections in section II-II.

The distillate elements 1 according to the drawing belong to a membrane distiller, which may comprise a large number of similar elements arranged one on top of the other, as shown in FIG. Each element 1 comprises two bags formed by a film layer 4 joined together at their edges 2, connected by spot welds 3 or the like, and a transverse end strip 5 of the element at the upper end of the element, which acts as a liquid distributor. The strip 5 is intended to supply a liquid to the film surface 4 forming the outer surface of the element, which evaporates inside the element due to the heat transfer from the condensable steam fed between the film layers. The heating steam used is steam generated on the membrane surfaces 4 of the elements, which is circulated inside the elements via a compressor (not shown).

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The end strip 5 of the element acting as a liquid distributor contains ductwork in the left and right halves of the element, which, according to Fig. 1, are mirror images of each other. Each duct system comprises a wider main duct 6, the inlets 35 of which are located at the end 9 of the strip and which makes a bend 10 of about 180 ° near the vertical center line of the element (dashed line 11 in Fig. 1). Between the bend 10 and the outlet end 8, the main channel 6 is flat and gently directed downwards, and in the meantime a series of feed channels 12 94217 leading to the membrane surface 4 of the element are comb-like, of equal length and directed obliquely from the main channel backwards towards said element centerline 11. in Fig. 1 the flowable evaporative fiber suspension 13 is drawn, while the right-hand ductwork is provided with only flow arrows.

In practice, the same liquid suspension is, of course, fed to the membrane surface of the element from both ductwork.

The purpose of the liquid divider 5 shown in the drawing is to provide as uniform an application of the evaporating liquid as possible to the membrane surface 4 of the element. clogging.

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The shown strip-like liquid distributor 5 can be made, for example, of plastic by tying the shaped pieces 14 delimiting the main channels 6 and the supply channels 12 between two opposite plastic plates 15 (cf. Fig. 2). It is possible that the steam channels leading inside the elements 1 are also connected to the strip-like liquid distributor 5, although these are not shown in the drawing as irrelevant to the invention. It is further possible to include in the liquid distributor common or separate liquid channel ducts which supply liquid to each membrane surface 4 of the same element 1. In the solution according to Figure 2, each liquid distributor 5 supplies liquid to opposite membrane surfaces 4 of two adjacent elements 1. therefore drawn slightly apart, but in practice they are pressed against each other when the distiller is in operation.

It will be clear to a person skilled in the art that the various embodiments of the invention are not limited to the example given above, but may vary within the scope of the appended claims.

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Claims (10)

A liquid dispenser (5) for a film distiller, formed by a strip at the upper end of a bag-like distillate element (1) of film material, having parallel supply channels (12) for spreading the liquid to be evaporated transversely to the outer surface (4) of the element. ) includes a transverse main channel (6) of the element (1), from which parallel supply channels (12) leading to the surface (4) of the element branch. 2. A method according to claim 1, comprising a channel (6) for genomic listeners (5) and a screen for the channel 20 (12). The average number of genome channels (8). Liquid distributor according to Claim 1, characterized in that the main duct 10 (6) is guided through the strip (5) so as to divide part of the liquid flow into the supply ducts (12) as the remainder leaves the main duct outlet end (8). 3. A method according to claim 2, comprising a plurality of channels (6), in which case a matrix channel (12) is provided, which is further encapsulated and inertly closed. 25 * Liquid distributor according to Claim 2, characterized in that the main duct (6), from which the supply ducts (12) branch, is substantially even and extensively downwards. A method according to claim 2 or 3, which can be used as a matrix channel (12) according to the invention (6). Liquid distributor according to Claim 2 or 3, characterized in that the supply channels (12) branch from the main channel (6) to the rear slope. 5. The viewfinder of the face of the patent patent, the turnout of the attachment channel (12) being substantially free of thread. Liquid distributor according to one of the preceding claims, characterized in that the supply channels (12) are substantially the same length. 5,94217 6. Vätskefördelare enligt nägot av de föregäende patentkraven, kännetecknad av att listen innehäller tvä amusadanaler (6) som är belägna i elementets (1) olika hal-vor och kanema (12), somförgrenar sig frän vardera amudekanalen, är riktade mot 35 den vertical dimension line (11) and elements. Liquid distributor according to one of the preceding claims, characterized in that the strip comprises two main channels (6) located in different halves of the element (1) and in that the supply channels (12) branching from each main channel are directed towards the vertical center line (11) of the element. 7. A patent according to claim 6, which includes a handle (6) and a guide (7, 8) and a list (5) of a handle (9) and a handle 7 94217 with a handle (10) of 180 °. i närheten av elementets mittlinje (11), varvid matarkanalema (12) förgrenar sig frän huvudkanalen pä sträckan mellan nämnda sväng och huvudkanalens utloppsända (8). 5 8. Vätskefördelare enligt segot av de föregäende patentkraven, kännetecknad av att listen (5) utgör en integrenad del i det päsformiga distillerelementet (1). Liquid distributor according to Claim 6, characterized in that the inlet and outlet ends (7, 8) of the main ducts (6) are located at opposite ends (9) of the strip (5). (11), the supply channels (12) branching from the main channel by a section between said bend and the main channel outlet end (8). Liquid distributor according to one of the preceding claims, characterized in that the strip (5) is integral with the bag-like distillate element (1). : 9. A film distiller in which the supply of the liquid to be evaporated to the outer surfaces (4) of the bag-like distillate elements (1) of film material takes place from strip-like liquid distributors (5) at the upper ends 6 94217, each , the use of feed channels (12) leading to the surface of the element, for the evaporation treatment of a liquid suspension (13) containing solid particles. 5 Use of a film distiller according to claim 9 for the evaporation treatment of a fiber suspension (13). 10 1. Vätskefördelare (5) för en filmdestillerapparat som utgöres av en list som ligger i en övre ända av ett av filmmaterial bestäende päsformigt distillerel (1) och somehäller bredvid varandra liggande matarkanaler (12) för utdelning av entska advertising of elements (4), listening to the elements (5) of which elements (1) expression of the interest channel (6) of 15 elements of the account (4) led to the addition of a fixed maturity of the channel. 9. Användning av en filmdestillerapparat, i vilken vätskan som scall avdunstas account utsidor (4) av päsformiga, av filmmaterial bestaende destillerelement (1) inmata gen- 10 nom i elementens övre belre listformade vätskefördelare (5), var och en av vilka har ätminstone en i elementets tvärriktning genom fördelaren löpande huvud-kanal (6) samt frän denna förgrenande, bredvid varandra liggande, account elementets yta ledande matarkanaler (12), för avdunstning av en vätskesuspension (13) som inne-häller fasta particle. 15 10. The application of a film distillation apparatus according to claim 9 for the manufacture of fibers suspension.