Recovery tower for VCM (Vinyl Chloride) gas in waste alkali liquor in calcium carbide method PVC (Polyvinyl Chloride) production process

Abstract

The utility model relates to a recovery tower of VCM gas in waste lye in calcium carbide method PVC production process, including distillation still, heater, recovery tower and condenser, the distillation still is installed at the bottom of recovery tower, the condenser is installed at the top of recovery tower, one end of heater is arranged in the distillation still, the other end of heater is arranged in the recovery tower, and the other end of heater is arranged in the recovery tower. The distillation kettle, the recovery tower and the condenser are integrated, and the joints of the distillation kettle, the recovery tower and the condenser are communicated. Through the structure, the problems that an existing recovery tower needs to be matched with a corresponding reboiler and a corresponding tower top condenser, the occupied area is large, the process is complex, the operation involved range is wide, and the number of sealing points is large are solved.

Description

Technical Field

[0001] The utility model relates to the technical field of alkali liquor recovery, in particular to a VCM gas recovery tower in waste alkali liquor in the production process of PVC by calcium carbide process. Background Art

[0002] Polyvinyl chloride, abbreviated as PVC (Polyvinyl chloride) in English, is a polymer formed by the polymerization of vinyl chloride monomer (VCM) in the presence of initiators such as peroxides and azo compounds, or by the free radical polymerization mechanism under the action of light or heat. Vinyl chloride homopolymers and vinyl chloride copolymers are collectively referred to as vinyl chloride resins.

[0003] PVC is an amorphous white powder with a small degree of branching, a relative density of about 1.4, a glass transition temperature of 77-90°C, and begins to decompose at around 170°C. It has poor stability to light and heat. At temperatures above 100°C or after prolonged exposure to sunlight, it will decompose to produce hydrogen chloride, and further autocatalytically decompose, causing discoloration and a rapid decline in physical and mechanical properties. In practical applications, stabilizers must be added to improve stability to heat and light.

[0004] PVC was once the world's most produced general-purpose plastic, and it is widely used in building materials, industrial products, daily necessities, floor coverings, floor tiles, artificial leather, pipes, wires and cables, packaging films, bottles, foaming materials, sealing materials, fibers, etc.

[0005] In the existing PVC production industry using the calcium carbide method, the intermediate process of vinyl chloride synthesis produces a certain amount of waste alkali liquid, which contains a large amount of VCM and acetylene gas dissolved in it and needs to be recycled through a recovery tower. The current recovery tower must be equipped with a corresponding reboiler and top condenser, which occupies a large area, has a relatively complex process, involves a wide range of operations, and has many sealing points. Utility Model Content

[0006] The utility model provides a VCM gas recovery tower in the waste alkali solution in the production process of PVC by calcium carbide method, which solves the problems that the existing recovery tower must be equipped with corresponding reboilers and top condensers, occupies a large area, has a relatively complex process, involves a wide range of operations and has many sealing points.

[0007] The technical solution of the utility model to solve the above technical problems is as follows:

[0008] The distillation kettle is installed at the bottom of the recovery tower, the condenser is installed at the top of the recovery tower, one end of the heater is arranged in the distillation kettle, the distillation kettle, the recovery tower and the condenser are integrated, and the connection points of the distillation kettle, the recovery tower and the condenser are connected.

[0009] The beneficial effect of the utility model is that by modifying the VCM gas recovery tower in the waste alkali liquid, the distillation kettle at the bottom of the tower, the recovery tower and the condenser at the top of the tower are integrated into one. At the same time, the heater and the distillation kettle are of a mosaic design, which not only effectively utilizes the space, but also can directly and effectively heat and evaporate the material. It not only achieves the purpose of recovering the VCM gas in the waste alkali liquid, but also reduces the floor space and construction scope, and also reduces the process operation scope and sealing point. It can be widely used in the process of evaporating volatile gases in chemical production, reducing production costs and improving distillation efficiency.

[0010] On the basis of the above technical solution, the present invention can also be improved as follows.

[0011] Furthermore, a nitrogen filling port, a standby port, and a pressure gauge port are provided at the top of the distillation kettle, a material discharge port and a sewage discharge port are provided at the bottom of the distillation kettle, and a thermometer port, an upper pipe port of a liquid level gauge, and a lower pipe port of a liquid level gauge are provided on one side of the distillation kettle.

[0012] The beneficial effect of adopting the above further scheme is that the nitrogen filling port can be used as a replacement for the three-in-one tower, the pressure gauge port can monitor the distillation effect of the three-in-one tower kettle by installing a pressure gauge, the thermometer port can monitor the heating effect of the heater by installing a thermometer, the liquid level gauge port can monitor the liquid level of the material in the distillation kettle by installing a liquid level gauge, and the spare port can be used for other purposes. The sewage outlet fixedly installed at the bottom of the distillation kettle can be used for maintenance and sewage discharge, and the material can be discharged through the fixed discharge port at the bottom.

[0013] On the basis of the above technical solution, the present invention can also be improved as follows.

[0014] Furthermore, the still has a still body, the heater is embedded in the still body, and the still body and the still are supported by a slide.

[0015] The beneficial effect of adopting the above further scheme is that the heater is embedded in the cylinder of the distillation kettle. Since the heater is designed as a tube in series and a hot water inlet and outlet are fixedly installed on the heater, the waste alkali liquid in the distillation kettle can be heated by hot water.

[0016] On the basis of the above technical solution, the present invention can also be improved as follows.

[0017] Furthermore, a hot water outlet is provided at the top of the heater, and a hot water inlet is provided at the bottom, and both the hot water outlet and the hot water inlet are provided with flanges.

[0018] The beneficial effect of adopting the above further scheme is that a hot water outlet and a hot water inlet are fixedly installed on the heater, and the hot water outlet and the hot water inlet are sealed by a flange, so that the hot water heats the waste alkali liquid in the distillation kettle.

[0019] On the basis of the above technical solution, the present invention can also be improved as follows.

[0020] Furthermore, the recovery tower is a packed tower, a feed port is provided on the recovery tower, packing is provided inside the recovery tower, a sieve plate is provided at the bottom of the packing, a pressure plate and a limiter are provided at the top, a sieve plate support is provided at the bottom of the sieve plate, a redistributor is provided between the sieve plate and the sieve plate support, and the sieve plate support is fixed to the recovery tower through a flange.

[0021] The beneficial effect of adopting the above further scheme is that the filler filled inside the recovery tower is a special filler, and the filler is pressed and limited by a pressure plate and a limiter. The hot steam rising from the distillation kettle passes through the filler in the recovery tower and the liquid phase material condensed by the top condenser for mass and heat transfer.

[0022] On the basis of the above technical solution, the present invention can also be improved as follows.

[0023] Furthermore, a sieve plate, a sieve plate support and a redistributor form a group, and a plurality of groups of sieve plates, sieve plate supports and redistributors are distributed on the recovery tower.

[0024] The beneficial effect of adopting the above further scheme is that the liquid is screened by the sieve plate and then kept evenly distributed downstream in the tower by the redistributor.

[0025] On the basis of the above technical solution, the present invention can also be improved as follows.

[0026] Furthermore, the bottom of the condenser is connected to the recovery tower, the bottom of the condenser is provided with a lower tube plate, the upper part is provided with an upper tube plate, and the top is provided with an upper head.

[0027] The beneficial effect of adopting the above further solution is that the condenser is sealed and installed on the top of the recovery tower through the upper head, and the components inside the condenser are installed and fixed through the lower tube plate and the upper tube plate.

[0028] On the basis of the above technical solution, the present invention can also be improved as follows.

[0029] Furthermore, a cold water inlet is provided at the bottom of the condenser, a cold water outlet is provided at the top, an air outlet is provided at the top, and a bumper plate is provided at the bottom of the air outlet.

[0030] The beneficial effect of adopting the above further solution is that the condenser has a cold water inlet and a cold water outlet, and the cooling water cools and condenses the inside of the condenser shell through the cold water inlet and the cold water outlet.

[0031] On the basis of the above technical solution, the present invention can also be improved as follows.

[0032] Furthermore, the interior of the condenser is provided with a spacing tube, a baffle and a heat exchange tube. There are multiple baffles. The spacing tube and the heat exchange tube pass through the multiple baffles. Both ends of the spacing tube and the heat exchange tube are respectively arranged on the upper tube plate and the lower tube plate.

[0033] The beneficial effect of adopting the above further solution is that the multiple baffles inside the condenser are relatively fixed in the shell side of the condenser, so that the cooling water flows in an S shape in the shell side, thereby increasing the cooling area of ​​the cooling water.

[0034] On the basis of the above technical solution, the present invention can also be improved as follows.

[0035] Furthermore, a pull rod is provided inside the condenser, and two ends of the pull rod are respectively arranged on the upper tube plate and the lower tube plate.

[0036] The beneficial effect of adopting the above further solution is that the multiple baffles are fixed in the shell side of the condenser by the tie rods, so that the baffles will not be deformed when the cooling water flows. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The utility model is a schematic structural diagram of a VCM gas recovery tower in waste alkali liquid in the production process of PVC by calcium carbide process.

[0038] In the attached drawings, the components represented by the reference numerals are as follows: 1-heater; 5-slideway support; 6-distiller body; 7-filler; 8-sieve plate; 9-sieve plate support; 10-redistributor; 11-flange; 12-stopper; 13-upper head; 14-lower tube sheet; 15-pull rod; 16-spacer tube; 17-baffle; 18-heat exchange tube; 19-anti-collision plate; 20-upper tube sheet; 21 -hot water outlet; 22-hot water inlet; 23-drain outlet; 24-discharge outlet; 25-lower pipe outlet of liquid level gauge; 26-upper pipe outlet of liquid level gauge; 27-thermometer port; 28-nitrogen filling port; 29-spare port; 30-pressure gauge port; 31-feed port; 32-cold water inlet; 33-cold water outlet; 34-gas outlet; 35-distillation kettle; 36-recovery tower; 37-condenser. DETAILED DESCRIPTION

[0039] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0040] Example 1

[0041] like Figure 1As shown, the distillation kettle 35 is installed at the bottom of the recovery tower 36, the condenser 37 is installed at the top of the recovery tower 36, one end of the heater 1 is arranged in the distillation kettle 35, the distillation kettle 35, the recovery tower 36 and the condenser 37 are integrated, and the connection points of the distillation kettle 35, the recovery tower 36 and the condenser 37 are connected.

[0042] Specifically, the waste alkali liquid enters the recovery tower 36 and the distillation kettle 35 through the feed port 31 on the recovery tower 36. The waste alkali liquid in the distillation kettle 35 is heated by the heater 1, and the rising hot steam passes through the special filler 7 in the recovery tower 36, and then enters the condenser 37. The condenser 37 is designed as a tube-in-tube, and the inside of the tube side is connected to the recovery tower 36. The inside of the shell side of the condenser 37 is cooling water, and the materials inside the tube side are cooled and condensed. The waste alkali liquid transfers mass and heat with the condensed liquid phase material, and the evaporated gas to be recovered is discharged from the combined recovery tower 36 through the top condenser 37.

[0043] like Figure 1 As shown, the top of the distillation kettle 35 is provided with a nitrogen filling port 28, a standby port 29, and a pressure gauge port 30, the bottom of the distillation kettle 35 is provided with a discharge port 24 and a sewage outlet 23, and one side of the distillation kettle 35 is provided with a thermometer port 27, an upper pipe port 26 of a liquid level gauge, and a lower pipe port 25 of a liquid level gauge.

[0044] Specifically, the three-in-one tower is replaced through the nitrogen filling port 28, the distillation effect of the integrated tower kettle is monitored through the pressure gauge installed through the pressure gauge port 30, the heating effect of the heater 1 is monitored through the thermometer installed through the thermometer port 27, and the liquid level of the material in the distillation kettle 35 is monitored through the liquid level gauge installed through the liquid level gauge port. The spare port 29 can be used for other purposes. The sewage outlet 23 fixedly installed at the bottom of the distillation kettle 35 is used for maintenance and sewage discharge, and the material is discharged through the discharge port 24 fixedly set at the bottom.

[0045] like Figure 1 As shown, the still 35 has a still body 6, the heater 1 is embedded in the still body 6, and the still body 6 and the still 35 are supported by a slide 5.

[0046] Specifically, hot water enters the heater 1 through the hot water inlet 22 and the hot water outlet 21 fixedly installed on the heater 1, and the waste alkali liquid in the distillation kettle 35 is heated by the hot water.

[0047] like Figure 1 As shown, a hot water outlet 21 is provided at the top of the heater 1 , and a hot water inlet 22 is provided at the bottom. Both the hot water outlet 21 and the hot water inlet 22 are provided with a flange 11 .

[0048] Specifically, hot water enters the heater 1 through the hot water inlet 22 of the heater 1 and is then discharged through the hot water outlet 21 . The hot water forms a reflux in the heater 1 and heats the waste alkali solution in the distillation kettle 35 .

[0049] like Figure 1 As shown, the recovery tower 36 is a packed tower, a feed port 31 is provided on the recovery tower 36, a packing 7 is provided inside the recovery tower 36, a sieve plate 8 is provided at the bottom of the packing 7, a pressure plate and a limiter 12 are provided at the top, a sieve plate support 9 is provided at the bottom of the sieve plate 8, a redistributor 10 is provided between the sieve plate 8 and the sieve plate support 9, and the sieve plate support 9 is fixed to the recovery tower 36 by a flange 11.

[0050] Specifically, the waste alkali liquid enters the recovery tower 36 through the feed port 31, and then enters the distillation kettle 35. The heated waste alkali liquid in the distillation kettle 35 enters the packing 7 through the sieve plate 8 and the redistributor 10, and the liquid is screened by the sieve plate 8. The redistributor 10 keeps the waste alkali liquid uniformly distributed in the downstream of the tower, and then enters the condenser 37 through the special packing 7, and transfers mass and heat with the liquid phase material condensed by the tower top condenser 37.

[0051] like Figure 1 As shown, a sieve plate 8 , a sieve plate support 9 and a redistributor 10 form a group, and a plurality of groups of sieve plates 8 , sieve plate supports 9 and redistributors 10 are distributed on the recovery tower 36 .

[0052] Specifically, the liquid is screened by multiple sets of sieve plates 8, and then the liquid is evenly distributed downstream in the tower by multiple sets of redistributors 10, so as to filter the VCM gas in the waste alkali liquid and recover the VCM gas.

[0053] like Figure 1 As shown, the bottom of the condenser 37 is connected to the recovery tower 36, the condenser 37 has a lower tube sheet 14 at the bottom, an upper tube sheet 20 at the top, and an upper head 13 at the top.

[0054] Specifically, the condenser 37 is sealed and installed on the top of the recovery tower 36 through the upper head 13. And the components inside the condenser 37 are installed and fixed through the lower tube sheet 14 and the upper tube sheet 20.

[0055] like Figure 1 As shown, a cold water inlet 32 ​​is provided at the bottom of the condenser 37 , a cold water outlet 33 is provided at the top, an air outlet 34 is provided at the top, and a bumper plate 19 is provided at the bottom of the air outlet 34 .

[0056] Specifically, the cooling water enters the condenser 37 through the cold water inlet 32 ​​and is then discharged from the condenser 37 through the cold water outlet 33 . The cooling water forms a reflux in the condenser 37 to cool and condense the waste alkali liquid in the condenser 37 .

[0057] like Figure 1 As shown, the interior of the condenser 37 is provided with a spacing tube 16, a baffle 17 and a heat exchange tube 18. There are multiple baffles 17. The spacing tube 16 and the heat exchange tube 18 pass through the multiple baffles 17. Both ends of the spacing tube 16 and the heat exchange tube 18 are respectively arranged on the upper tube plate 20 and the lower tube plate 14.

[0058] Specifically, the cooling water forms an S-shaped flow in the condenser 37 through the multiple baffles 17 . The S-shaped flow increases the cooling area of ​​the cold water and enhances the cooling and condensation of the waste alkali liquid in the condenser 37 .

[0059] like Figure 1 As shown, the condenser 37 further has a tie rod 15 inside, and both ends of the tie rod 15 are respectively arranged on the upper tube plate 20 and the lower tube plate 14.

[0060] Specifically, the tie rods 15 fix the plurality of baffles 17 in the shell side of the condenser 37, so that the baffles 17 will not be deformed when the cooling water flows.

[0061] The beneficial effect of this embodiment is that by modifying the VCM gas recovery tower 36 in the waste alkali liquid, the bottom distillation kettle 35, the recovery tower 36 and the top condenser 37 are integrated into one. At the same time, the heater 1 and the distillation kettle 35 are of a mosaic design, which not only effectively utilizes the space, but also can directly and effectively heat and evaporate the material. It not only achieves the purpose of recovering the VCM gas in the waste alkali liquid, but also reduces the floor space and construction scope, and also reduces the process operation scope and sealing point. It can be widely used in the process of evaporating volatile gases in chemical production, reducing production costs and improving distillation efficiency.

[0062] The working process of this embodiment is as follows: the waste alkali liquid enters the recovery tower 36 and the still 35 through the feed port 31 on the recovery tower 36. The waste alkali liquid in the still 35 is heated by the heater 1, and the rising hot steam passes through the special filler 7 in the recovery tower 36, and then enters the condenser 37. Because the condenser 37 is a tube-in-tube design, the inside of the tube side is connected to the recovery tower 36, and the inside of the shell side of the condenser 37 is cooling water, which cools and condenses the materials inside the tube side. The waste alkali liquid transfers mass and heat with the condensed liquid phase material, and the evaporated gas to be recovered is discharged from the combined recovery tower 36 through the top condenser 37, and the discarded waste alkali liquid is discharged through the discharge port 24.

[0063] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0064] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present utility model, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0065] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0066] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0067] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0068] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present invention. Ordinary technicians in the field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A VCM gas recovery tower in waste alkali liquor during the production of PVC by calcium carbide process, characterized in that: The invention comprises a distillation kettle (35), a heater (1), a recovery tower (36) and a condenser (37), wherein the distillation kettle (35) is installed at the bottom of the recovery tower (36), the condenser (37) is installed at the top of the recovery tower (36), one end of the heater (1) is arranged in the distillation kettle (35), the distillation kettle (35), the recovery tower (36) and the condenser (37) are integrated, and the connection points of the distillation kettle (35), the recovery tower (36) and the condenser (37) are connected.

2. A VCM gas recovery tower in waste alkali liquor in a calcium carbide process PVC production process according to claim 1, characterized in that: The top of the distillation kettle (35) is provided with a nitrogen filling port (28), a standby port (29), and a pressure gauge port (30); the bottom of the distillation kettle (35) is provided with a material discharge port (24) and a sewage discharge port (23); one side of the distillation kettle (35) is provided with a thermometer port (27), an upper pipe port (26) of a liquid level gauge, and a lower pipe port (25) of a liquid level gauge.

3. A VCM gas recovery tower in waste alkali liquor in a calcium carbide process PVC production process according to claim 2, characterized in that: The still (35) has a still cylinder (6), the heater (1) is embedded in the still cylinder (6), and the still cylinder (6) and the still (35) are supported by a slideway (5).

4. A VCM gas recovery tower in waste alkali liquor in a calcium carbide process PVC production process according to claim 2, characterized in that: The heater (1) is provided with a hot water outlet (21) at the top and a hot water inlet (22) at the bottom. Both the hot water outlet (21) and the hot water inlet (22) are provided with flanges (11).

5. The VCM gas recovery tower in the waste alkali liquor in the production process of PVC by calcium carbide process according to claim 1, characterized in that: The recovery tower (36) is a packed tower. A feed port (31) is provided on the recovery tower (36). A packing (7) is provided inside the recovery tower (36). A sieve plate (8) is provided at the bottom of the packing (7). A pressure plate and a stopper (12) are provided at the top. A sieve plate support (9) is provided at the bottom of the sieve plate (8). A redistributor (10) is provided between the sieve plate (8) and the sieve plate support (9). The sieve plate support (9) is fixed to the recovery tower (36) via a flange (11).

6. A VCM gas recovery tower in waste alkali liquor in the production process of PVC by calcium carbide process according to claim 5, characterized in that: One sieve plate (8), one sieve plate support (9) and one redistributor (10) form a group, and a plurality of groups of sieve plates (8), sieve plate supports (9) and redistributors (10) are distributed on the recovery tower (36).

7. The VCM gas recovery tower in the waste alkali liquor in the production process of PVC by calcium carbide process according to claim 5, characterized in that: The bottom of the condenser (37) is connected to the recovery tower (36), and the condenser (37) has a lower tube sheet (14) at the bottom, an upper tube sheet (20) at the top, and an upper head (13) at the top.

8. The VCM gas recovery tower in the waste alkali liquor in the production process of PVC by calcium carbide process according to claim 5, characterized in that: The condenser (37) is provided with a cold water inlet (32) at the bottom, a cold water outlet (33) at the top, an air outlet (34) at the top, and a bumper plate (19) at the bottom of the air outlet (34).

9. The VCM gas recovery tower in the waste alkali liquor in the production process of PVC by calcium carbide process according to claim 7, characterized in that: The condenser (37) has a spacing tube (16), a baffle (17) and a heat exchange tube (18) inside, the baffle (17) has a plurality of pieces, the spacing tube (16) and the heat exchange tube (18) pass through the plurality of baffles (17), and both ends of the spacing tube (16) and the heat exchange tube (18) are respectively arranged on the upper tube plate (20) and the lower tube plate (14).

10. A VCM gas recovery tower in waste alkali liquor in the production process of PVC by calcium carbide process according to claim 7, characterized in that: The condenser (37) further comprises a pull rod (15) inside, and two ends of the pull rod (15) are respectively arranged on the upper tube plate (20) and the lower tube plate (14).

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