Energy-saving process tower for polyester production

Abstract

The utility model discloses an energy-saving process tower for polyester production, which comprises a tower body used for accommodating gas and liquid media, and a diameter-expanding kettle body is arranged at the lower end of the tower body; the gas distributor is positioned in the middle of the inner cavity of the diameter-expanded kettle body, the top center of the gas distributor is connected with a gas inlet pipe, and a plurality of guide vanes for rotating gas are uniformly arranged along the circumference of the gas distributor; the liquid distributor is positioned at the upper part of the inner cavity of the tower body, a main inlet is in butt joint with a tower top liquid reflux inlet penetrating through the side wall of the tower body, and a plurality of liquid distribution openings are uniformly formed in the cross section of the tower body; the wall-flow-free structured packing is arranged on the cross section of the tower body below the liquid distributor; the guide liquid collector is arranged on the cross section of the tower body below the wall-flow-free structured packing, and a liquid outlet is positioned above the lower tower plate; and the tower plates are positioned below the guide liquid collector and are alternately arranged in multiple layers from top to bottom. The process tower can significantly reduce the reflux ratio and heat consumption, and effectively control the content of heavy components at the tower top.

Description

TECHNICAL FIELD

[0001] The utility model relates to a process column, especially to an energy -conserving process column for polyester production belongs to polyester production equipment technical field for bottle -grade, spinning grade, membrane grade, engineering plastics etc. BACKGROUND

[0002] Polyester production is a complex chemical process, mainly with purified terephthalic acid (PTA) and ethylene glycol (EG) as raw material, through esterification and polycondensation reaction to generate polyester product. Polyester production system usually includes the following several main parts: slurry preparation, esterification reaction, pre-polycondensation reaction, final polycondensation reaction, chip production and packaging etc. links. Among them, the process column is one of the key equipment, mainly used for separating water generated by esterification reaction and gaseous ethylene glycol evaporated from the reaction kettle.

[0003] The process column utilizes the difference between the boiling points of water and ethylene glycol to separate water and ethylene glycol by rectification. Water as light component is discharged from the top of the column, while ethylene glycol as heavy component is discharged from the bottom of the column and recycled for reuse. Similarly, it is also applicable to the separation and purification of multi-component medium in esterification reaction, and the separation process of the process column is crucial to maintain the balance of esterification reaction and improve the esterification rate. However, the traditional process column has the following problems:

[0004] 1. Multiple plate columns are used, there is no gas distributor at the gas phase inlet, and ordinary liquid distributor is used for reflux at the top of the column, so the separation efficiency is low;

[0005] 2. Only structured packing is used at the top of the column, there is no liquid collector below the packing, and the reflux ratio is as high as 1.1-1.2, which leads to an increase in the pressure difference of the column and high pressure requirement of the equipment;

[0006] 3. When the column is increased in height, the on-site equipment layout needs to be re-planned, increasing the cost.

[0007] The utility model discloses a kind of polyester process columns, including cylinder one and cylinder two, cylinder one and cylinder two are connected by inverted cone, cylinder one includes upper head and cylinder one body, detachable temperature measuring seat is equipped on the upper head, and the center of the upper head is tower top steam outlet, lug and condensate reflux port are equipped on the cylinder one body, liquid distributor, structured packing, flow guide cylinder and tray assembly are sequentially equipped in cylinder one from top to bottom, condensate reflux port is connected with liquid distributor by pipeline, cylinder two includes lower head and cylinder two body, spray liquid inlet, steam inlet and heat medium outlet are equipped on the cylinder two body. The technical scheme has the problems of gas phase feed short circuit, liquid distribution disc blockage, tower top pressure build-up etc.

[0008] The utility model discloses a kind of ethylene carbonate purification systems, including continuous rectification tower, continuous rectification tower overhead condenser, continuous rectification tower overhead reflux device, continuous rectification tower kettle reboiler, batch rectification tower, batch rectification tower overhead condenser, batch rectification tower overhead reflux device and batch rectification tower kettle reboiler.This technical scheme energy consumption is high, operation is complex, and the purity and yield of material of batch rectification tower are not ideal. SUMMARY

[0009] This part is to summarize some aspects of the embodiments of the utility model and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this part and the abstract of the specification and the utility model name, and such simplifications or omissions cannot be used to limit the scope of the utility model.

[0010] The utility model aims at, overcome the problems in the prior art, provide a kind of energy-saving process column for polyester production, can significantly reduce reflux ratio and heat consumption, effectively control tower top heavy component content, applicable to the occasion that the purity requirement of separation medium is high and energy saving and consumption reduction requirement is strict.

[0011] To solve the above technical problems, an energy-saving process column for polyester production of the utility model comprises:

[0012] Tower body, for containing gas and liquid medium, lower end is equipped with expansion kettle body;

[0013] Gas distributor, located in the inner cavity middle part of expansion kettle body, top center is connected with gas inlet pipe, and a plurality of guide vanes for making gas rotate are uniformly arranged along circumference;

[0014] Liquid distributor, located in the upper part of the inner cavity of tower body, total inlet is butt joint with tower top liquid reflux port passing through the lateral wall of tower body, and a plurality of liquid distribution ports are uniformly arranged on the cross section of tower body;

[0015] Wall-free flow regular packing, arranged on the cross section of tower body below liquid distributor;

[0016] Guiding liquid collector, arranged on the cross section of tower body below wall-free flow regular packing, and liquid flow outlet is located above lower tray;

[0017] Tray, located below guiding liquid collector, and a plurality of layers are alternately arranged from top to bottom.

[0018] As an improvement of the utility model, the inner cavity of the expansion kettle body is provided with a reboiler, and the reboiler is a heating coil or a heating tube.

[0019] As a further improvement of the present application, each tower plate is in the shape of a round angle with a plurality of air holes, the adjacent tower plates are 180 degrees out of phase at the angle position, and each tower plate is provided with a liquid downcomer extending vertically at the angle position, and the upper edge of each liquid downcomer forms the overflow edge of the tower plate, and the lower edge of each liquid downcomer is inserted into the liquid level of the lower tower plate.

[0020] As a further improvement of the present application, each air hole of the tower plate is provided with a float valve for one-way conduction upward.

[0021] As a further improvement of the present application, the liquid distributor comprises a distributor main pipe extending along the diameter of the tower body, one end of the distributor main pipe is connected to the tower top liquid return port through a flange, and the two sides of the distributor main pipe are symmetrically connected to distributor branch pipes pointing to the inner wall of the tower body, and the liquid distribution ports are uniformly distributed at the bottom of each distributor branch pipe and are respectively provided with a spray head.

[0022] As a further improvement of the present application, the guide liquid collector comprises a plurality of bending plates arranged obliquely and parallel to each other, the lower part of each bending plate is provided with a V-shaped bending to form a flow guide groove with an opening upward, each flow guide groove is located below the projection of the adjacent bending plate, the flow directions of each flow guide groove are consistent, and the outlet end of each flow guide groove is provided with a flow gap between the outlet end and the inner wall of the tower body, and the top tower plate is located below the outlet end of each flow guide groove.

[0023] As a further improvement of the present application, the upper side wall of the expanded diameter kettle body is provided with a crude alcohol inlet pipe, the inner end of the crude alcohol inlet pipe extends to the tower body axis, is bent upward, and is provided with a water film nozzle.

[0024] Compared with the prior art, the present application has the following beneficial effects: 1. The gas phase inlet with a gas distributor can ensure the distribution effect of gas entering, and the gas-liquid mass transfer is uniform; the tower top return with a liquid distributor can ensure that the liquid phase return is not deviated, and the theoretical tray number of the filler can be reduced; the tower top with a high-efficiency mass transfer filler has no wall flow; the filler is provided with a guide liquid collector below, which can control the liquid phase return to be concentrated on the top tower plate, and improve the utilization rate of the tower plate.

[0025] 2. The reflux ratio is reduced, the separation of water and ethylene glycol can control the reflux ratio R to be less than 0.8, the heat consumption is reduced, 150,000 kcal of heat can be saved per ton of water, the content of heavy components at the tower top is effectively controlled, the separation of water and ethylene glycol can control the ethylene glycol content at the tower top to be less than 0.1%, and the water content at the tower bottom is less than 2.5%. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical scheme of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained from these drawings without creative labor, and the drawings are provided for reference and illustration only, not to limit the present application. Among them:

[0027] Figure 1 It is a front view of the energy-saving process column for polyester production of the present application.

[0028] Figure 2 It is a top view of an embodiment of the gas distributor in the present application.

[0029] Figure 3 It is a top view of an embodiment of the liquid distributor in the present application.

[0030] Figure 4 It is a front view of an embodiment of the guide liquid collector in the present application.

[0031] Figure 5 It is Figure 4 a top view after removing the collector support in the present application.

[0032] In the figure: 1. Column body; 1a. Gas phase outlet; 1b. Manhole;

[0033] 2. Enlarged diameter kettle body; 2a. Liquid discharge port; 2b. Lug seat;

[0034] 3. Gas distributor; 3a. Guide vane;

[0035] 4. Liquid distributor; 4a. Tower top liquid return port; 4b. Distributor main pipe; 4c. Distributor branch pipe; 4d. Spray head; 4e. Distributor support;

[0036] 5. No-wall flow regular packing;

[0037] 6. Guide liquid collector; 6a. Guide groove; 6b. Collector support;

[0038] 7. Tray; 7a. Downcomer;

[0039] 8. Gas inlet pipe;

[0040] 9. Reboiler; 9a. Heat medium inlet; 9b. Heat medium outlet;

[0041] 10. Crude alcohol inlet pipe; 11. Skirt. DETAILED DESCRIPTION

[0042] In the following description of the utility model, the terms "front", "back", "left", "right", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the utility model and simplifying the description, and do not mean that the device must have a particular orientation.

[0043] In order to make the technical means, creative features, purposes and effects achieved by the utility model easy to understand, the utility model is further described below in combination with specific drawings. Obviously, the described embodiments are only part of the embodiments of the utility model, not all.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the utility model belongs. The terms used in the specification of the utility model are only for the purpose of describing specific embodiments and are not intended to limit the utility model.

[0045] As Figure 1 shown, the energy-saving process column for polyester production of the utility model, including tower body 1, the lower end of tower body 1 is connected with the expansion calandria 2 through the conical section, the expansion calandria 2 can adopt the support structure form of ear seat 2b or skirt 11.

[0046] The inner cavity middle part of expansion calandria 2 is equipped with gas distributor 3, the top center of gas distributor 3 is connected with the inner end of gas inlet pipe 8, and the outer end of gas inlet pipe 8 is out of the side wall of the conical section. Gas distributor 3 is immersed in liquid phase space, as Figure 2 shown, one of its embodiments is that a plurality of guide vanes 3a are uniformly arranged along the circumference, the gas phase material derived from the esterification reactor enters the gas distributor 3 from the gas inlet pipe 8, and under the guidance of each guide vane 3a, it flows out from the outer periphery of the gas distributor 3 and produces rotation, which facilitates the solid phase particles entrained in the gas to enter the liquid phase, and makes the gas-liquid mass transfer uniform, prevents solid entrainment, and ensures that there is no tower collision and tower blockage.

[0047] The inner cavity of expansion calandria 2 is equipped with reboiler 9, and the reboiler 9 is a heating coil or a heating tube. Taking the heating coil as an example, it is coiled along the inner wall of the expansion calandria 2, and the two ends are out of the side wall of the expansion calandria 2 and are respectively provided with a heat medium inlet 9a and a heat medium outlet 9b. According to the conditions of the customer, the reboiler 9 can adopt various heat sources such as heat conducting oil, steam, etc., for heating the liquid phase to make the small molecule gas phase overflow.

[0048] The inner cavity upper part of tower body 1 is equipped with liquid distributor 4, Figure 3As shown in some embodiments of the liquid distributor, the distributor main pipe 4b extends along the diameter of the tower body, one end of the distributor main pipe 4b is connected to the tower top liquid return port 4a through a flange, and the tower top liquid return port 4a penetrates the side wall of the tower body. The distributor branch pipes 4c are symmetrically connected to both sides of the distributor main pipe 4b and point to the inner wall of the tower body, the liquid distribution ports are uniformly distributed at the bottom of each distributor branch pipe 4c and are respectively provided with spray heads 4d. The lower part of the distributor branch pipe 4c and the other end of the distributor main pipe 4b are closed and supported on the distributor support 4e.

[0049] The tower top liquid return port 4a enters the distributor main pipe 4b, and then enters each distributor branch pipe 4c from the distributor main pipe 4b, and finally sprays downward from each spray head 4d of each distributor branch pipe 4c, so that the tower top liquid return water is uniformly distributed downward in the cross section of the tower body and is not affected by the gas flow, and the mass transfer is more uniform and efficient. The spray direction and flow of each spray head 4d can be adjusted to adapt to different operating conditions.

[0050] The cross section of the tower body below the liquid distributor 4 is provided with a wall-flow-free regular packing 5, which can effectively overcome the loss of separation efficiency caused by wall flow, and can control the wall flow of the packing to be below 2%.

[0051] The lower part of the wall-flow-free regular packing 5 is provided with a guide liquid collector 6, as shown in Figure 4 、 Figure 5 The guide liquid collector 6 includes a plurality of inclined and parallel bending plates, the lower part of each bending plate is respectively provided with a V-shaped bending to form an upwardly open flow guide groove 6a, each flow guide groove 6a is located below the projection of the adjacent bending plate, the flow direction of each flow guide groove 6a is consistent and the outlet end is provided with a flow gap between the inner wall of the tower body, the top tray is located below the outlet end of each flow guide groove 6a, and the outlet flow of each flow guide groove 6a falls on the top tray, avoiding the liquid falling into the gap of the top tray, which can improve the utilization rate of the topmost tray.

[0052] The upper end of each bending plate is also provided with a small downward bending part to improve the strength, and the upper and lower sides of the guide liquid collector 6 are respectively provided with collector supports 6b to fix each bending plate.

[0053] The lower part of the liquid guide collector 6 is provided with a plurality of layers of tower plates 7, each of which is a sector of a circle and is uniformly provided with a plurality of air permeable holes, and each of the air permeable holes is provided with a float valve, and the air flow from the lower part pushes the float valve to flow upwards. The sectors of the adjacent tower plates 7 are 180° out of phase, and each of the tower plates 7 is provided with a vertical liquid downcomer 7a at the sector, the upper edge of the liquid downcomer 7a forms the overflow edge of the tower plate, and the lower edge of the liquid downcomer 7a is inserted into the liquid level of the lower tower plate to form a liquid seal. The liquid falls on the upper tower plate and maintains a certain liquid level, overflows from the overflow edge of the sector, and flows along the liquid downcomer 7a to the lower tower plate, and thus alternately flows downwards, and reversely contacts with the gas, and the same number of tower plates can improve the washing and capturing effect of the gas phase without increasing the height of the tower body.

[0054] The upper part of the side wall of the diameter expansion kettle body 2 is provided with a crude alcohol inlet pipe 10, the inner end of the crude alcohol inlet pipe 10 extends to the tower body axis, is bent upwards, and is provided with a water film nozzle to strengthen the contact effect with the gas phase, the crude alcohol falls into the tower bottom, the liquid phase concentration in the diameter expansion kettle body 2 can be adjusted, and direct reuse is facilitated.

[0055] The bottom and the upper part of the side wall of the diameter expansion kettle body 2 are provided with a liquid level meter port for installing a liquid level meter to monitor the liquid level in the kettle. The center of the kettle bottom is provided with a liquid discharge port 2a. The center of the top of the tower body 1 is provided with a gas phase outlet 1a for discharging the captured gas. The tower body side wall above the liquid distributor 4 is provided with a manhole 1b for facilitating entering the tower body for installation or maintenance.

[0056] The top of the tower body 1 is provided with a pressure port P1, and the upper part of the side wall of the diameter expansion kettle body 2 is provided with a pressure port P2, so as to facilitate observing the pressure difference in the tower to avoid tower blocking.

[0057] The top of the tower body 1, the liquid phase of the tower plate, and the bottom of the diameter expansion kettle body 2 are provided with temperature measuring ports T1-T11 for monitoring the temperature at each position.

[0058] The above only describes the preferred embodiments of the present application, shows and describes the basic principles, main features and advantages of the present application, and is not limited to the patent protection range of the present application. It should be understood by those skilled in the art that the present application is not limited by the above embodiments. In addition to the above embodiments, the present application can have other implementation manners without departing from the spirit and scope of the present application. The present application can also have various changes and improvements, and any technical solution formed by equivalent replacement or equivalent transformation falls within the protection scope of the present application. The protection scope of the present application is defined by the appended claims and their equivalents. The technical features not described in the present application can be realized by or using the prior art, which will not be described here.

Claims

1. An energy-saving process tower for polyester production, characterized in that, include: The tower body is used to contain gaseous and liquid media, and the lower end is equipped with an expanded-diameter vessel. The gas distributor is located in the middle of the inner cavity of the expanded diameter vessel. The top center is connected to the gas inlet pipe, and multiple guide vanes that make the gas rotate are evenly arranged along the circumference. The liquid distributor is located in the upper part of the inner cavity of the tower body. The main inlet is connected to the liquid return port at the top of the tower that passes through the side wall of the tower body, and multiple liquid distribution ports are evenly provided on the cross-section of the tower body. Wallless flow structured packing is disposed on the cross-section of the tower body below the liquid distributor; A guide liquid collector is installed on the cross-section of the tower body below the wallless flow structured packing, with the liquid outlet located above the lower tray; The tray is located below the guide liquid collector and has multiple layers arranged alternately from top to bottom.

2. The energy-saving process tower for polyester production according to claim 1, characterized in that: The inner cavity of the expanded diameter vessel is equipped with a reboiler, which is a heating coil or a heating tube.

3. The energy-saving process tower for polyester production according to claim 1, characterized in that: Each tray has a missing corner and multiple vent holes evenly distributed. The missing corner positions of adjacent trays are 180° out of phase. Each tray has a vertically extending downcomer at the missing corner. The upper edge of each downcomer forms the overflow edge of the tray, and the lower edge of each downcomer is inserted into the liquid level of the tray below.

4. The energy-saving process tower for polyester production according to claim 3, characterized in that: Each vent hole of the tower plate is equipped with an upward-directing unidirectional float valve.

5. The energy-saving process tower for polyester production according to claim 1, characterized in that: The liquid distributor includes a distributor main pipe extending along the diameter of the tower body, one end of which is connected to the liquid reflux port at the top of the tower via a flange; distributor branch pipes pointing towards the inner wall of the tower body are symmetrically connected to both sides of the distributor main pipe, and the liquid distribution ports are evenly distributed at the bottom of each distributor branch pipe and are each equipped with a nozzle.

6. The energy-saving process tower for polyester production according to claim 1, characterized in that: The guiding liquid collector includes multiple inclined and parallel bent plates. The lower part of each bent plate is provided with a V-shaped bend to form an upward-opening guide channel. Each guide channel is located below the projection of the adjacent bent plate. The flow direction of each guide channel is consistent, and there is a flow gap between the outlet end and the inner wall of the tower. The top tower plate is located below the outlet end of each guide channel.

7. The energy-saving process tower for polyester production according to any one of claims 1 to 6, characterized in that: The upper side wall of the expanded diameter vessel is provided with a crude alcohol inlet pipe, the inner end of which extends to the axis of the tower body, bends upward, and is provided with a water film nozzle.

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