FI73138C - Selective condensing apparatus. - Google Patents

Description

731 38

Selective condenser

The invention relates to the condensation of steam in industrial processes by means of a plate-type condenser.

In many industrial applications, the water or other steam generated in the evaporator is then condensed to remove steam from the system, reuse the water, or for some other reason. For example, surface condensers used in evaporation systems in the pulp and paper industry allow for the reuse of hot condensed water obtained from steam.

When condensing water or other vapor is carried in a vaporase by carrying components that are more volatile than water or other substances comprising the main component obtained by condensing, one way to treat the vapor is to condense all, including the most volatile substances, often in a significant amount of subcooling.

Various evaporation and condensation systems are described in Figures 11-17 on pages 11-25 of Perry's book "Chemical Engineer's Handbook", fourth edition, 1963.

U.S. Patent 3,789,954 relates to a distillation process and discloses a condensing section having an upper and a lower condensing chamber separated by a horizontal partition for separating the less volatile components of the condensable steam from the more volatile ones. U.S. Patent 3,261,392 discloses an evaporator having a vertical partition dividing the heating space, and plate type heat exchangers are described in U.S. Patent 3,332,469.

There is a lot of empirical and other published information regarding industrial heat exchange technology in general and various surface condensers in particular. So far, 2,731 38 fully satisfactory, industry-accepted systems have not been developed which efficiently distribute condensate in a plate-type heat exchanger, separating the concentrate of the more volatile components of the water or other steam to be condensed from the concentrate of the less volatile components. The present invention overcomes the difficulties encountered in prior systems and provides a highly efficient device for selective condensing.

The invention therefore relates to an apparatus for selectively condensing vapors contaminated with volatile substances, which apparatus comprises a heat exchanger with a flowable membrane housed in a housing. a combined collection space and a lower collection space connected to the lower part of all heat exchange elements, and the device according to the invention is characterized in that the lower collection space is divided by partitions into at least three compartments and the upper collection space is divided into at least three compartments by partitions, the lower collection space is connected to the first compartment the last compartment of the upper collection space is connected to a non-condensable gas discharge line, the lower collection space each compartment has a condensate outlet line, and each compartment except the last one in the upper compartment is ducted to the next compartment of the lower compartment so that the condensed steam first flows upwards through the lower and upper collector compartments when the above operation is repeated for the heat exchanger elements connected to this and other compartments of the lower and upper collection space, the relatively pure condensate formed in the first group of heat exchanger elements is removed via the first condensate line, the through the condensate drain line.

The first compartment of the lower and upper assembly space is preferably larger in volume than the other compartments, while the last compartment is preferably smaller in volume than the other compartments.

As the cooling medium, continuously running cooling water can be used, which heats up as it condenses steam, or cooling water which is circulated by means of a circulating pump and cooled by evaporation outside the system shown in the figures before being returned to the condenser, cooling medium, or evaporator. In the latter case, where water to be evaporated or other liquid is used as a cooling medium for condensing the steam in the heat exchange elements, the flow of the liquid as a thin film along the outer surfaces of the heat exchange elements causes a considerable amount of coolant to evaporate. Thus, while the interior of the heat exchange elements acts as a condenser, the space outside the heat exchange elements and inside the chamber acts as an evaporator.

The relatively clean condensate stream from the first largest group of elements is substantially odorless and can be returned to the plant without further treatment.

The separated contaminated water stream can be passed to a distillation column or the like for post-treatment.

These and other objects and advantages of the selective condensing system according to the invention will be best apparent from the following detailed description of the invention, particularly in conjunction with the accompanying drawing.

The drawing shows a section of a device according to the invention which is adapted to provide several separate condensate streams.

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The condenser according to the invention, generally indicated at 110, has a jacket-shaped chamber comprising substantially vertical front and rear walls and two side walls 114. Inside the chamber there is a group of separate parallel downflow membrane heat exchange elements 115. The heat exchange elements 115 are formed of two spaced apart flat plates secured together at their edges to provide enclosed spaces within the elements 115. A suitable method of making heat exchanger elements made of sheets is described in prior U.S. Patent 3,512,239. As will be appreciated by those skilled in the art, the elements 115 may be used to condense as with water.

The device according to the figure is divided to separate several different condensates. The lower openings 127 and the upper openings 137 of the separate heat exchange elements 115 are divided into four groups by partitions. The condensable steam is led through the inlet line 126 to a space 100 which communicates with a number (7 in the figure) of heat exchange elements 115 through their lower openings 127 to condense part of the steam in these elements 115 as the steam flows upwards inside the elements. The non-condensable steam passing upwards through these first group elements 115 ends in a space 101 at the upper ends of the first group elements 115. The condensate formed in the first group elements 115 is relatively free of low condensable substances and is removed from the lower elements 115 via a discharge line 141 as condensate I. The space 101 is closed except the openings 137 of the first group of heat exchange elements and the dashed channel C1 leading from the space 101 of the non-condensable steam to the space 102 communicating with the second group of elements 115 through their lower openings 127. The steam travels upwards 5,731 38 inside the elements 115 of this second group, some of which condenses and exits via the discharge line 142 as condensate II, while the non-condensable residue ends up in the space 103 at the tops of the elements. upwards within the third group of heat exchange elements 115, whereby condensation still takes place and the condensate leaves through the outlet line 143 to the condensate stream III. The steam ending in the upper space 105 passes down to the last lower space 106 via the channel C3, and the last flow upwards through the plurality of heat exchange elements 115 (3 elements in the figure) causes further condensation of the non-condensable steam components. . The gases and residual non-condensable vapors exit the space 107 at the upper end of the last group of heat exchange elements 115 through the outlet line 136, as shown in the upper right figure.

The means for conducting the coolant into the chamber and distributing the fluid evenly on the surfaces of the heat exchange elements 115 comprises a perforated, substantially horizontal plate plate 116 mounted above and spaced from the heat exchange elements 115. Water or other coolant flows through the holes in the plate 116, pouring down along the outer surfaces of the heat exchange elements 115. Preferably, the coolant is not flowed directly onto the plate 116, but is directed to an overhead pool 117 located above the plate 116, with the liquid flowing over the edges of the pool 117 and thus more evenly distributed on the plate 116. No very large amounts of coolant from the pool 117 are required. The figure shows a pipe 118 leading to a basin 117 for supplying coolant thereto.

As shown in the figure, water or other coolant that has passed over the heat exchange elements 115 along their entire vertical length accumulates at the bottom of the chamber 11, where the inwardly converging lower portions of the walls form a trough 124.

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The liquid is discharged from the trough 124 through an outlet channel 125. If necessary, the inlet pipe 118 can supply additional new coolant to the plate 116. If recirculation of the coolant is desired, a pump and liquid-cooling means can be used before returning the liquid.

One advantage of the preferred structure associated with fluid flow outside the heat exchange elements is to provide a uniform and efficient coolant flow along the outer surfaces of the heat exchange elements 115 to condense water or other steam within the elements 115.

The flow of steam through the inner parts of the heat exchange elements 115 has been discussed above, and the coolant flowing down along the outer surfaces of the heat exchange elements has only been treated as a cooling medium for the steam to be condensed. However, it is also important to take into account the evaporation of this coolant due to the heat transferred from the condensing steam. As water or other coolant flows down the heat exchanger elements 115 as a film, a considerable amount of liquid evaporates. This effect can be advantageously exploited by using an evaporating liquid as a cooling medium. Thus, when the interior of the heat exchange elements 115 acts as a condenser, the space outside the elements 115 and inside the chamber acts as an evaporator.

For example, by means of a pump (not shown), the liquid circulated to the plate 116 is mixed with the evaporating liquid passed through the pipe 118, and the generated vapors travel outwards between the heat exchange elements 115 as the hot steam inside the elements 115 heats the liquid. The generated steam rises to the top above the plate 116. The rear wall of the chamber may be located away from the nearest heat exchange element 115 so that the generated steam can flow out and up inside the chamber. The steam can then be allowed to pass upwards either past the plate 116 or through a duct to the upper end of the chamber to which a droplet separator or the like (not shown)

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7 73138) may be located for treating steam generated by evaporation of the coolant. The figure shows the removal of steam from the chamber from the center 150 of its upper end, but it will be apparent to those skilled in the art that a droplet separator may be located at 150 to trap liquid droplets carried by the steam stream.

An embodiment has been described above which separates four different condensates, but it is clear that three or more than four condensates can be separated in the device according to the invention.

Various modifications, applications, component replacements, and structural variations in the form of the presently preferred embodiment in the device described above may occur to those skilled in the art of heat exchange technology and are considered to be within the scope of this invention.

Claims (8)

8,731 38 An apparatus for selectively condensing vapors contaminated with volatiles, the apparatus comprising a flowable heat exchanger (115) housed in a housing, wherein the steam is condensed from the outer surfaces of the heat exchange elements (115) substantially downstream of each of the two exchanger coolant streams; -connected plate, a collection space connected to the upper part of all heat exchange elements (115) and a lower collection space connected to the lower part of all heat exchange elements (115), characterized in that the lower collection space is divided by at least three compartments (100, 102, 106) and the upper collection space is divided by at least the three compartments (101, 103, 107), the first compartment (100) of the lower compartment are connected to the condensing steam supply line (126) and the last compartment (107) of the upper compartment is connected to the non-condensable gas outlet line. to (136), each compartment (100, 102, 106) of the lower collection space has a condensate discharge line (141, 142, 144), and each compartment (101, 103) of the upper collection space except the last (107) is on the channel (cl, c2). , c3) connected to the next compartment (102, 106) of the lower collection space so that the steam to be condensed must first flow upwards through the heat exchange elements (115) connected to the first compartment (100, 101) of the lower and upper collection space and then downwards through the duct (cl ) to the second compartment (102) of the lower collection space, the above operation being repeated at the heat exchange elements (115) connected to this and other compartments of the lower and upper collection space, the relatively pure condensate formed in the first group of heat exchange elements (115) being removed via the first condensate discharge line (141); 115) condensate of a degree of impurity formed in the following groups is removed from the condensate drain lines of these groups (14 2, 144), and the non-condensable gases are removed via a condensate drain line (136). 9,731 38 Device according to claim 1, characterized in that the first compartment (100, 101) of the lower and upper assembly space is larger in volume than the other compartments. Device according to Claim 1 or 2, characterized in that the last compartment (106, 107) of the lower and upper compartment is smaller in volume than the other compartments. Device according to one of the preceding claims, characterized in that it comprises means (116, 117, 118) located above the heat exchange elements (115) for distributing coolant to the outer surfaces of the heat exchange elements, collecting coolant below the heat exchange elements and a discharge line connected to the upper end of the housing. 150) to remove vapor evaporated from the coolant. Device according to claim 4, characterized in that it comprises means for circulating the coolant accumulated in the compartment (124) to the liquid distribution means (116, 117, 118) located above the heat exchange elements (115). Device according to one of the preceding claims, characterized in that the lower and upper assembly spaces are divided into four compartments (100, 102, 104, 106 and 101, 103, 105, 107). 731 38 1 p 1. A selective condenser with a flame-retardant capacitor, comprising a capacitive condenser with a flame-retardant element (115); varvid varje värmeväxlarelement (115) bestär av tvä tillnärmelsevis parallella, utmed väsentligen alla te kanter sammanfogade plätar et ettil samtliga värmeväxlarelements (115) övre partier anslutet samlingsrum och et account samtliga värmeväxlarelements (115) In the case of the same genome, the genome must be added to the third genome (100, 102, 106) and to the same genome as the other genome must be added to the third genome (101, 103, 107), to the same number. (100) is connected to the in-line led (126) for a single condenser and to the same time the condenser (107) is connected to the condenser (136) for condensing gas, and the shielding (100, 102, 106) and detergent drum (141, 142, 144) for condensing and shielding (101). , 103) and in the case of a sampler of the system (107) and in the genome of the channel (c1, c2, c3) are used in the form of a sample (102, 106) and in the case of a sampler, in the case of underscores and subdivisions of the subframe (115) and in the same way in the genome channel (cl) of the subdivisions and subdivisions (102) värmeväxlarelementen (115), varvid det i den första Gruppen av värmeväxlarelement (115) bildade förhällandevis Rena condensatet uttages genom den fenssta condensatutloppsledningen (141), det i de feljande grupperna av värmeväxlarelement (115) shows the degree of condensation in the genome of condensation in the genome (142, 144) from the group, and the condensation of gas in the genome of condensation (136).