FI79948B - Evaporator condenser for distillation unit - Google Patents

Abstract

This invention concerns a distillation unit comprising a shell (1), a fan (2), the pre-heat exchangers (7) and (8) and an evaporator condenser (25) formed by the pairs of membranes (13). One pair of membranes (13) can be removed from the evaporator condenser (25) at a time and replaced with a new one. The pair of membranes (13) is made of plastic or similar material and they hang freely in the evaporator condenser.<IMAGE>

Description

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EVAPORATIVE CONDITIONER OF THE DISTILLER

The invention relates to an evaporator condenser, for example for a distillate operating on the steam compressor principle, which comprises a body part, a fan, preheat exchangers, an evaporator condenser and piping.

Briefly, the operating principle of a steam compressor distiller is as follows: The liquid to be distilled is first heated with distillate and waste water in preheaters, after which the feed water is led to the evaporator. Steam is sucked from the evaporator by means of a fan and the waste water flows to the bottom of the evaporator. After the fan, the steam pressure and temperature rise. From the fan, the steam is led to the condenser, where it condenses and the heat is transferred to the water fed to the evaporator, which evaporates. The distillate flows under the influence of gravity to the bottom of the apparatus. The evaporation temperature can be selected as desired by changing the internal pressure of the appliance. Temperatures of 50 to 60 ° C are quite commonly used, in which case the device has the necessary vacuum.

The most common use of steam compressor distillates has been in the production of fresh water from seawater. Evaporator condensers of known devices are of the tubular or plate heat exchanger type. Distillation of seawater has been problematic with these devices for two main reasons.

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Seawater is highly corrosive under distillation conditions and corrosion problems are great. Therefore, titanium and nickel copper, for example, have had to be used as evaporator materials. Due to special mixtures, the devices have become expensive and their price competitiveness has deteriorated compared to alternative methods such as reverse osmosis.

Another problem with known distillation equipment has been the fouling of thermal surfaces. The properties of different seawater in this respect vary considerably and the design of the equipment has required knowledge of water chemistry. The metal surface is rigid and provides a good adhesion base to slag. Due to the above, existing equipment has had to be washed and rinsed periodically during the operating period.

The purpose of the device according to the invention is to eliminate the above-mentioned drawbacks and to improve usability as well as to facilitate maintenance.

The device according to the invention is characterized by what is stated in the claims below.

The advantage of the evaporator condenser according to the invention compared to those currently in use is the cheap construction. When heat transfer surfaces are made of a thin plastic film, the price per unit area is only a fraction of those made of titanium. Plastic raw materials are known to be very resistant to corrosion and therefore there are no corrosions on the heat transfer surfaces made of plastic.

The disadvantage of plastics is their poor thermal conductivity, which easily leads to large areas. In steam compressor distillers, the pressure difference between the evaporator and the condenser is only 150-300 mm from the water column. Therefore, very thin film thicknesses can be used in the structure according to the invention, whereby the heat transfer properties are almost of the same order as for metals.

The use of thin films for maintenance is possible thanks to the demountable structure. Each pair of membranes can be removed separately from the evaporator condenser and replacement can be performed under operating conditions.

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The device according to the invention is also not sensitive to soiling, because the heat transfer surfaces are flexible. If dirt adheres to surfaces, it can be shaken off by pressure fluctuations.

Figure 1 shows a distillate according to the invention seen from the side and in cross-section.

Figure 2 is a front view of the evaporator condenser.

Figure 3 shows a pair of films.

Figure 4 shows the support and tension parts of the steam supply openings.

In Figure 1, the number (1) indicates the body of the distiller. The number (2) refers to the fan. Number (3) shows the steam duct and numbers (4) and (5) the steam suction and supply chambers. The distillation water supply line is (6). The preheaters are (7) and (8). Distillate and effluent removal lines are (9) and (10). Sewage and distillate catchment areas are shown at (11) and (12). The evaporator condenser membrane pair is marked with the number (13) and the membrane spot weld (23). The support part number of the film pair is (14).

The tension members at the bottom of the steam supply opening are (15) and the vertical tensioners (16). Numbers (17) and (18) refer to the supports of the film pair. The water tank to be distilled is number (19) and the distribution pipes (20). The droplet separator is number (21). The distillate exits along the pipe (22) between the pair of membranes.

The distillation apparatus according to Figure 1 operates as follows: The water to be distilled is fed via a supply line (6) via preheaters (7) and (8) to a distribution basin (19), from where it flows through pipes (20) into the membrane between the pairs where it evaporates. Non-evaporating water drains into the basin (11). The steam generated by the blower (2) is blown into the slots of the membrane pairs, where it condenses and flows through the pipes (22) into the basin (12). The heat of the distillate and wastewater is transferred to the feed water, which substantially increases the efficiency of the device.

4 79948 The evaporator condenser membrane pairs are made of a closed iron-on membrane sock, the upper and lower edges of which are welded closed and a support part (14) with grooves (24) for pipes is placed at the upper edge. In order to form a gap of the desired size between the films of the pair of films (13), the films are welded together with spot welds (23). The lower edge of the membrane pair is made oblique so that the distillate flows into the tube (22).

The side of the support members (14) has openings for the supply of steam. The membrane pairs (13) are bonded together after the membrane at the steam supply opening has been cut open. The bonding takes place with vertical clamps (16), which also act as seals and prevent steam from entering the evaporator side.

The film pairs are tied to the frame with tensioners (15). The support member (14) rests on the supports (17) and (18) and the lower part of the film pair hangs freely. The distance between the evaporator and condenser slots is desired by varying the number of spot welds (23) and the thickness of the support members (14). In the Sol of the evaporator, the membranes can be attached to each other at the most bulging points, thus strengthening the structure. From the point of view of heat transfer, an expanding and contracting shrinkage is very advantageous.

If a film tears during use, the Film Pair can be replaced by removing the clamping parts (15) and (16) and loosening the entire film pack, after which the Film Pair can be replaced without special tools.

The invention is not limited to the application shown in the drawing. It is clear that the device according to the invention can also be applied to numerous other objects.

Claims (7)

An evaporator compressor distillation plant consisting of a body (1), a fan (2), an evaporator condenser (25) and the preheating exchangers (7) and (8), characterized in that the evaporator condenser (25) is formed by closed membrane pairs (13). ) of plastic or similar material, and that the membrane pair (13) can be removed at a time from the evaporator condenser (25) without disassembling any other construction. Installation according to Claim 1, characterized in that the support parts (14) of the membrane pair (13) form the bottom of the water basin (19) for distilling water, and that the support parts (14) are provided with a water distribution pipe (24) (24). 20). Installation according to claim 1, characterized in that the support part (14) is inside the membrane pair (13) and that the sides of the support part (14) have openings for meadow feeding, and that the membrane pairs (13) are bonded to each other at the edges of the mound openings by means of clamps (16). ). Installation according to claim 1, characterized in that the membrane pairs (13) hang freely in the supports (17) and (18) in the upper part of the evaporator condenser (25). Installation according to Claim 1, characterized in that the lower part of the membrane pair (13) is inclined and provided at the bottom with a drain pipe (22). Installation according to Claim 1, characterized in that the membranes of the membrane pair (13) are supported to one another by spot welds (23) or similar connections. Installation according to claim 1, characterized in that the bottom part of the evaporator condenser (25) functions as distillate (12) and residual water basin.