JP2018058008A - Gas-liquid contactor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas-liquid contactor capable of achieving excellent and efficient gas-liquid contact, while suppressing a pressure loss caused by gas-liquid contact.SOLUTION: A gas-liquid contactor 1 has a gas-liquid contact part having a filler 2 constituted of a plurality of vertical flat plates juxtaposed at an interval, a liquid supply part for supplying liquid to the gas-liquid contact part from above, and a gas introduction part for introducing gas to the gas-liquid contact part. The liquid supply part has a liquid distributor 4 in which the density of drip points for supplying the liquid to the gas-liquid contact part is 500 points/mor more.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a gas-liquid contact device that can be used as a gas purification device, a gas separation device, a cooling device, or the like that separates, removes or recovers a specific gas component, and promotes mass transfer or energy transfer by gas-liquid contact. About.

  Conventionally, gas separation devices that separate, remove, or recover specific gases from gas to liquid contact using gas-liquid contact are used in chemical plants and thermal power plants. Yes. For example, in a carbon dioxide recovery device, by absorbing and separating carbon dioxide by bringing a gas containing carbon dioxide into contact with an absorption liquid such as an aqueous solution of monoethanolamine, and contacting the gas and liquid while heating the absorption liquid after absorption. Carbon dioxide is released into the gas phase and recovered. Also, in gas purification devices for removing harmful gas components from exhaust gas and gas separation devices for separating specific gas components from mixed gas, absorption of the specific gas components by the absorbing liquid is achieved using gas-liquid contact. Done. Furthermore, gas-liquid contact is also used in a cooling device that cools a high-temperature liquid or gas.

  In general, an apparatus for performing gas-liquid contact has a filler for increasing the contact area between the liquid and the gas, and the liquid and gas are brought into gas-liquid contact on the surface of the filler so that a specific gas in the gas is obtained. Absorb ingredients and heat into liquid. Various types of fillers useful for increasing the gas-liquid contact area have been proposed.

  Fillers with complex shapes and structures take time and labor to process and load, greatly increasing the manufacturing cost and labor. Is being used. For example, Patent Document 1 below describes a gas separation device using an expanded metal plate as a filler.

  Patent Document 2 below describes a gas-liquid contact device using a gas-liquid contact plate whose surface shape is devised so as to increase the area where the liquid spreads on the filler.

International Publication No. 2013/015415 Pamphlet JP 2002-306958 A

  Since the above-described filler and gas-liquid contact plate are plate-like and have a relatively simple structure, the loading operation into the apparatus is relatively easy. However, the manufacturing process of the filler remains a problem of labor and cost. In addition, due to the shape of the filler surface, pressure loss due to flow resistance occurs when gas is supplied, so that energy consumption during operation becomes a problem.

  In this regard, the use of a flat plate (thin layer material) can reduce the manufacturing cost of the filler. In this case, a large number of vertical flat plates are juxtaposed, liquid is supplied from above, gas is supplied to the gap between the flat plates, and the liquid flowing down on the flat plate is brought into contact with the gas passing through the gap. In such a configuration, there is little pressure loss due to gas flow resistance, and energy consumption during operation can be kept low.

  However, when a flat plate is used as a filler, the gas-liquid contact area tends to decrease due to insufficient wetting of the filler by the liquid. That is, since the liquid flowing down vertically on the plane is difficult to spread in the lateral direction, if the liquid distribution state is uneven, a surface that does not get wet with the liquid is generated, and the gas-liquid contact efficiency is lowered. For this reason, it is necessary to devise so that the whole surface of a filler can fully be utilized.

  The present invention was devised in view of the above-described problems, and suppresses pressure loss in gas-liquid contact, while eliminating liquid wetting failure and realizing good and efficient gas-liquid contact. It is an object to provide an apparatus.

  In order to solve the above-mentioned problems, the present inventors have examined the liquid supply to the filler, and found that good gas-liquid contact can be realized in combination with a specific liquid distributor.

According to one aspect of the present invention, a gas-liquid contact device includes a gas-liquid contact portion having a filler constituted by a plurality of vertical flat plates arranged in parallel at intervals, and liquid from above to the gas-liquid contact portion. A liquid supply unit that supplies the gas, and a gas introduction unit that introduces gas into the gas-liquid contact unit, and the liquid supply unit has a drip point density of 500 points / m for supplying liquid to the gas-liquid contact unit. ^The gist is to have ^two or more liquid distributors.

The liquid distributor may include a nozzle or a claw that vertically supplies liquid from the drip point by free fall. The liquid distributor may have a guide claw that guides liquid to each of the drip points using gravity flow. It is preferable that the density of the drip points is 1000 to 3000 points / m ² .

  Providing a gas-liquid contact device that can achieve good gas-liquid contact and efficient component transfer while suppressing pressure loss during gas-liquid contact, and has good energy efficiency during operation Is possible.

The schematic block diagram which shows one Embodiment of a gas-liquid contact apparatus. Schematic which shows an example of the distribution pipe of a liquid distributor. Schematic which shows one Embodiment of the guidance nail | claw of a liquid distributor. The graph which shows the relationship between the absorption performance of a carbon dioxide when the gas-liquid contact apparatus is used for collection | recovery of a carbon dioxide, and the density of the drip point of a liquid distributor.

  Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating understanding of the invention, and do not limit the present invention. In the specification and the drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. .

  A gas-liquid contact device using a filler can be schematically described, for example, as shown in FIG. The gas-liquid contact device 1 has a container 3 in which a filler 2 is loaded, and these constitute a gas-liquid contact portion. The filler 2 is constituted by a plurality of vertical rectangular flat plates arranged in parallel at intervals. The gas-liquid contact device 1 includes a liquid supply unit that supplies liquid to the gas-liquid contact unit from above and a gas introduction unit that introduces gas into the gas-liquid contact unit. Specifically, a liquid distributor 4 is disposed above the filler 2 as a liquid supply unit, and a liquid supply line 5 is connected to the liquid distributor 4. The liquid L is supplied to the liquid distributor 4 through the liquid supply line 5, and the liquid L flows down from the liquid distributor 4 to the filler 2. Further, a gas supply line 6 is connected to the lower portion of the container 3 as a gas introduction unit, and the gas G supplied through the gas supply line 6 is introduced into the bottom of the gas-liquid contact device 1. The liquid L supplied to the filler 2 flows down along the surface of the flat plate erected vertically, and contacts the gas G rising in the space between the flat plates. During this gas-liquid contact, the liquid L forms a liquid film on the filler 2, for example, absorbs a specific component in the gas G, and the gas G ′ from which the specific component has been removed is the top of the container 3. It is discharged to the outside through a gas discharge line 7 connected to. The liquid L ′ functioning as the absorbing liquid is stored at the bottom of the container 3 and then discharged to the outside through the drainage line 8 connected to the bottom.

  Various columnar fillers 2 such as a polygonal columnar filler and an elliptical columnar shape can be configured using a flat plate, not limited to a rectangular columnar or cylindrical filler. In the case of constituting a cylindrical filler, the shape of the flat plate is a rectangle corresponding to a parallel cross section obtained by cutting the column at equal intervals along the axial direction, and the horizontal widths of the flat plates used are different. In a state where all the flat plates are arranged and the filler 2 is assembled, it is loaded into a container 3 having an annular side wall.

  As described above, the shapes of the filler 2 and the container 3 can be appropriately designed as necessary, and the shape of the filler 2 can be appropriately selected from various axial shapes. In addition, the filler 2 in the embodiment of FIG. 1 has a three-stage structure in which three filler units are stacked in the vertical direction, with a filler unit configured using a predetermined number of flat plates as one unit. However, it is not limited to this, The filler 2 can be comprised using one or more arbitrary numbers of filler units as needed. A mesh plate may be interposed between the filler units, which is useful for improving the stability of the support structure. Further, the parallel direction of the flat plates can be changed for each stage of the filler unit. For example, if the upper plate is loaded so that the parallel direction of the flat plates is perpendicular to the parallel direction of the lower plate, the stability of the structure is good.

  The wetting area per unit volume (gas-liquid contact area), the gas flow rate, and the gas flow resistance change depending on the thickness and spacing of the flat plate in the filler 2, so that a suitable flow space can be obtained in consideration of these factors. The number of flat plates is set. The interval between the flat plates can be fixed, for example, with a spacer interposed. What is necessary is just to adjust the dimension and installation position of a spacer suitably so that the flow of gas and a liquid may not be prevented. The gas flow resistance when the gas and the liquid are brought into contact affects the energy consumption during operation. In the gas-liquid contact device 1, the flow path of the gas G and the liquid L in the filler 2 is a straight and simple gap between the parallel flat plates, and can be said to have the least flow resistance. In addition, the manufacturing cost can be kept low. Therefore, in order to reduce the operating cost, it is effective to configure the filler 2 using such a plurality of parallel flat plates. Further, it is useful as a filler for gas-liquid contact, which requires a large capacity treatment and a high-speed treatment.

  However, the flow of the liquid L flowing down on the surface of the flat plate tends not to spread sideways. For this reason, the part in which a liquid film is not formed with a liquid tends to arise, and a wetting area (gas-liquid contact area) reduces. Furthermore, the flow rate of the liquid L increases and the time during which the liquid stays on the surface of the filler is shortened, and the gas-liquid contact efficiency is reduced. In order to suppress the reduction of the wetted area, it is important to devise the supply of the liquid L so as to distribute the liquid as evenly as possible to the horizontal upper surface formed by the upper end of the flat plate constituting the filler 2. .

  As a means for supplying a liquid, for example, a spray device is known. However, the spraying device needs power to eject the liquid. Also, since the liquid is discharged from the spray nozzle in a conical shape, the liquid supply surface is circular, and in the liquid supply by a plurality of spray nozzles, there are portions where the sprays overlap and portions that are not sprayed, and uniform supply is difficult. is there. In other words, the uniform liquid supply by the spray device is possible only when the upper surface of the filler 2 is a considerably small circular surface. In this regard, the liquid distributor 4 that supplies the liquid vertically from the drip point can supply the liquid uniformly over the entire upper surface of the filler 2 regardless of the size and shape of the upper surface of the filler 2. Therefore, it is easy to make a design change corresponding to the shape of the upper surface of the filler 2 without affecting the liquid distribution.

When the liquid distributor is used in combination with the filler 2 constituted by a flat plate, there is a unique condition in which the effectiveness is higher than expected. Specifically, the gas-liquid contact performance of the filler is not proportionally improved by increasing the drip point density (the number of liquid supply points per area) of the liquid distributor, but the drip point density is 500-1000. The degree of improvement in the gas-liquid contact performance is clearly different between the point / m ² region and the region of 1000 points / m ² or more. The improvement of the gas-liquid contact performance is remarkable when the density of drip points is around 500 points / m ² (specifically, refer to examples described later). Therefore, when providing the liquid distributor, it is effective to use a drip point density of 500 points / m ² or more, and a drip point density of 1000 to 3000 points / m ² is efficient. It is. Even if the density of drip points is increased to 3000 points / m ² or more, the improvement in gas-liquid contact performance is relatively small.

  The liquid distributor 4 for supplying liquid in the vertical direction from the drip point is generally composed mainly of a distribution pipe for guiding and distributing the liquid to each drip point, and an opening and a thin tube nozzle are provided at each drip point of the distribution pipe. Means for dropping the liquid, such as guide claws, are provided. Accordingly, the liquid supplied to the liquid distributor 4 is distributed to each drip point through the distribution pipe, freely falls from the dropping means, flows down vertically, and is supplied to the filler 2.

  FIG. 2 shows an example of a distribution pipe 41 constituting the liquid distributor 4. The distribution pipe 41 has a single horizontal main pipe 42 and a plurality of branch pipes 43 that branch from the side of the main pipe 42 in the horizontal direction, and the branch pipes 43 extend in parallel to both sides of the main pipe 42. At the bottom of the main pipe 42 and the branch pipe 43, an opening 44 is formed at a position corresponding to the drip point.

  In FIG. 2, the opening 44 is provided as a means for dropping the liquid, but it may be changed so that a nozzle in the vertical direction is provided or a guide claw is attached. For example, when the distribution pipe 41 is made of a plastically deformable material such as a metal, when forming the opening 44, plastic processing is performed so that the edge of the opening 44 protrudes outward, and It can be formed into a distribution pipe 41 such that an extremely short tubular nozzle projects integrally. Further, a narrow tube nozzle communicating with the opening 44 may be joined. In this case, the openings 44 may be provided on both sides of the branch pipe 43 so that vertical nozzles are attached to both sides of the branch pipe 43 in parallel.

  In FIG. 2, the length of the branch pipe 43 is set so that the tip of the branch pipe 43 forms a circle, and the liquid supply surface by the distribution pipe 41 is configured to be circular. However, by changing the length of the branch pipe 43, the liquid can be dropped onto the supply surface of another shape. For example, when the lengths of the branch pipes 43 are made equal to each other, the liquid can be evenly supplied to the filler 2 whose upper surface has a square or rectangular shape.

  The form in which the guide claws are provided as the dropping means is advantageous in increasing the density of the drip points. FIG. 3 is a view for explaining an embodiment in which guide claws are provided as dropping means of the liquid distributor, and is a vertical sectional view of a branch pipe. In FIG. 3, the upper part of the branch pipe 43 ′ has a straight outlet 45, and the liquid supplied from the main pipe 42 to the branch pipe 43 ′ overflows equally from the outlet 45 to both sides of the branch pipe 43 ′. Get out. Guide plates 46 are attached to both sides of the branch pipe 43 ′ and extend obliquely downward from the edge of the outlet 45. The lower portion of the guide plate 46 is cut in the vertical direction so as to form a large number of parallel strips, and the strip-shaped portion is used as the guide claw 47. Every other guide claw 47 is refracted at the root so as to alternate. Furthermore, the tip portions of the guide claws 47 extending obliquely downward are each appropriately refracted near the tip so as to face vertically downward. In order to prevent contamination of the liquid L in the branch pipe 43 ′, the upper part of the outlet 45 is covered with a cover 48, and the shape of the cover 48 is appropriately designed so as not to disturb the gas flow.

  By providing the guide claw 47 as described above, the liquid L overflowing from the outlet 45 of the branch pipe 43 ′ flows down on the guide plate 46 by gravity and falls from the tip of the guide claw 47. Therefore, by adjusting the tip of the guide claw 47 so as to coincide with the drip point, the liquid can be guided to each of the drip points using the flow due to gravity. The drip point is clarified by processing the tip of the guide claw 47 to be tapered. It is possible to position the tip of the guide claw 47 by adjusting the length and refraction of the guide claw 47, and it is possible to adjust the tip position so that the drip points are evenly distributed.

  Since the strength of the flat plate decreases as the flat plate is thinned, reinforcing means may be used as necessary when using a thin flat plate to increase the gas-liquid contact area per volume. Examples of the reinforcing means include a form in which ribs are attached to both sides of a flat plate, and support and fixing using clips or the like, but may be appropriately selected from known means and applied. A reinforcement effect may be obtained by devising the arrangement of the spacers.

  Examples of the gas G to be processed by the gas-liquid contact apparatus 1 using the filler 2 as described above include waste gas (exhaust gas) and reaction gas generated in facilities such as a chemical plant and a thermal power plant, Often, carbon dioxide, acidic gases such as nitrogen oxides and sulfur oxides are treated as specific components. Depending on the specific component to be removed from the gas G, the liquid L used as the absorbing liquid is selected. For example, for recovering and removing carbon dioxide, an alkali such as a cyclic amine compound, an alkanol amine, a phenol amine, or an alkali metal salt is used. An aqueous solution of an agent is often used, and an aqueous solution of an alkaline agent such as a calcium compound or a magnesium compound is generally used to remove sulfur oxides. In a monoethanolamine (MEA) aqueous solution often used in the recovery of carbon dioxide, a carbamate / amine salt (carbamate), carbonate, bicarbonate, etc. are produced by reaction with carbon dioxide.

  For this reason, each part which comprises the gas-liquid contact apparatus 1 is manufactured with the raw material which has the tolerance with respect to the chemical agent contained in the component of the gas G and the liquid L which were mentioned above. Examples of such materials include metals such as stainless steel, aluminum, nickel, titanium, carbon steel, brass, copper, monel, silver, tin, and niobium, and resins such as polyethylene, polypropylene, and PTFE. The filler 2 and the flat plate constituting it are also made of a corrosion-resistant material that does not cause a reaction (corrosion) with the gas G to be processed and the liquid L to be used, as described above. The material may be a surface roughness such as sanding, sand blasting, ultraviolet ozone treatment, plasma treatment, or the like that is formed with fine irregularities on the surface and surface modification by coating or the like. Depending on the quality, the material may be prepared so as to meet the use conditions as described above. The flat plate is a flat plate or a thin layer material having a uniform thickness, and the material and the thickness can be appropriately selected so as to maintain a suitable strength according to the conditions for performing the gas-liquid contact. Metal mesh using metal wires, punching metal plates, expanded metal plates, etc. are plate materials that can reduce weight while maintaining strength to the extent that they can stand alone, and even in the spread of liquid wetting Excellent properties. Therefore, when it is very fine, it can be handled in the same manner as a flat plate, and may be used to configure the filler 2 of the gas-liquid contact device 1.

  In the above description, the gas-liquid contact device 1 has been described as a contact form in which the gas G and the liquid L are opposed to each other. It is also possible to change to a contact form in which the liquid L is parallel. The gas-liquid contact apparatus 1 is not limited to the gas-liquid contact apparatus for absorbing, separating, and removing the specific components as described above, but is used for cooling, heating, dissipation, etc. included in various chemical plant processes. It is also possible to apply to an apparatus (cooling tower, heating tower, diffusion tower (regeneration tower), etc.).

  A distribution pipe as shown in FIG. 2 was prepared, and a thin tubular nozzle was attached to the opening of the main pipe and the branch pipe and used for the production of the liquid distributor. At this time, liquid distributors having different drip point densities were produced by changing the number of openings and nozzles.

A flat plate made of stainless steel (SUS304) was prepared, and each flat plate was cut into a lateral width suitable for forming a cylindrical filler with flat plates arranged at equal intervals. In a state in which all the flat plates are arranged through the spacer and the filler 2 is assembled, it is loaded into a container 3 having an annular side wall. One of the liquid distributors prepared above (drip point density: 138 points / m ² ) was installed above the filler 2 to complete the assembly of the gas-liquid contact device 1.

<Carbon dioxide absorption treatment>
Aqueous amine solution as the absorbing solution was prepared, the gas-liquid contact apparatus 1, the gas in the gas flow rate of 2m / s (the cold air), flow ratio of the absorption liquid to the flow rate of 3L / m ³ of liquid-to-gas ratio (gas ) To form a steady liquid and gas flow, and then 5% carbon dioxide was added to the gas to continue the supply. During this time, the pressure loss of the gas and the concentration of carbon dioxide in the outlet gas were measured (measurement M1).

  Furthermore, the liquid distributor in the gas-liquid contact device 1 was replaced with another liquid distributor having a different drip point density, and the same gas-liquid contact and measurement as described above were repeated to measure the absorption concentration of carbon dioxide. (Measurements M2 to M7). Each of the measurements M2 to M7 was evaluated as a relative ratio based on the carbon dioxide absorption performance in the measurement M1. The results are shown in Table 1 and the graph of FIG.

According to Table 1 and FIG. 4, it is understood that the carbon dioxide absorption performance is rapidly improved in the vicinity of the density of the drip points in the measurement M3. From this, when the density of the drip points of the liquid distributor is set to about 500 points / m ² or more, the absorption performance of the filler by the parallel vertical plates can be improved efficiently.

(Table 1)
Measurement M1 M2 M3 M4 M5 M6 M7
Drip point density 138 331 662 1325 1658 2319 4306
Carbon dioxide absorption performance 1 1.05 1.25 1.38 1.33 1.29 1.45

The filler 2 of the gas-liquid contact device 1 is replaced with a commercially available regular packing (Melapak (trade name), Sulzer Chemtech, a packing in which corrugated corrugated plates with inclined ridges are arranged in parallel), and the drip point A liquid distributor with a density of 138 points / m ² was installed, and the same gas-liquid contact and measurement as described above were performed (measurement M8). Further, the liquid distributor was changed to a drip point density of 1658 points / m ² , and gas-liquid contact and measurement were repeated in the same manner (Measurement M9). As a relative ratio based on the carbon dioxide absorption performance in measurement M8, the carbon dioxide absorption performance in measurement M9 was evaluated to be 1.11. From this result, it can be considered that the absorption performance of carbon dioxide in a commercially available regular packing does not improve much even if the drip point is increased. Therefore, the improvement in absorption performance by setting the drip point density of the liquid distributor as shown in Table 1 and FIG. 3 is a unique effect in combination with the fillers by the parallel vertical plates, and other fillers It cannot be obtained with the combination. That is, good gas-liquid contact efficiency can be realized by a combination of a filler made of a vertical flat plate and a liquid distributor having an appropriate number of drip points.

  A gas-liquid contact device with good energy efficiency during operation is provided, and good gas-liquid contact and efficient component transfer can be realized while suppressing pressure loss. In addition, it is possible to contribute to the improvement of efficiency in manufacturing and processing, and prevention of environmental pollution by the spread of exhaust gas treatment such as combustion gas. Moreover, it can contribute to the effective use of resources by reducing the weight of the apparatus and reducing manufacturing and processing costs.

DESCRIPTION OF SYMBOLS 1 Gas-liquid contact apparatus 2 Filler 3 Container 4 Liquid distributor 5 Liquid supply line 6 Gas supply line 7 Gas discharge line 8 Drain line 41 Divided pipe 42 Main pipe 43,43 'Branch pipe 44 Opening 45 Outlet 46 Guide plate 47 Guide claw 48 Cover L, L 'Liquid G, G' Gas

Claims (4)

A gas-liquid contact portion having a filler constituted by a plurality of vertical flat plates arranged in parallel at intervals;
A liquid supply unit for supplying liquid from above to the gas-liquid contact unit;
A liquid distributor having a gas introduction part for introducing gas into the gas-liquid contact part, wherein the liquid supply part has a drip point density of 500 points / m ² or more for supplying the liquid to the gas-liquid contact part A gas-liquid contact device.   The gas-liquid contact device according to claim 1, wherein the liquid distributor has a nozzle or a claw that vertically supplies liquid from the drip point by free fall.   The gas-liquid contact device according to claim 2, wherein the liquid distributor has a guide claw for guiding the liquid to each of the drip points using a flow due to gravity. Gas-liquid contact apparatus according to any one of claims 1 to 3 density of the drip point is 1000 to 3000 points / ^{m 2.}

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