Esterification vacuum device

Abstract

The utility model relates to the technical field of esterification equipment, in particular to an esterification vacuum device, which comprises a first-stage injection pump, a second-stage injection pump A, a second-stage injection pump B, a third-stage injection pump, a pre-polycondensation tail gas pipe, an intermediate polycondensation tail gas pipe and a final polycondensation tail gas pipe, the tail gas pretreatment tank is connected to the pressurizing machine through a pipeline, the pressurizing machine is connected to the tail gas mixing heat exchanger through a pipeline, an ethylene glycol supplementing pipe is arranged on the tail gas mixing heat exchanger, and a mixed tail gas conveying pipe of the tail gas mixing heat exchanger is respectively connected to the first-stage injection pump, the second-stage injection pump A, the second-stage injection pump B and the third-stage injection pump. According to the esterification vacuum device disclosed by the utility model, pre-polycondensation tail gas, intermediate polycondensation tail gas and final polycondensation tail gas are introduced into the corresponding stages of injection pumps, so that the use of EG steam is reduced, the energy consumption is greatly reduced, and the energy utilization rate is high.

Description

Technical Field

[0001] The utility model relates to the technical field of esterification equipment, in particular to an esterification vacuum device. Background Art

[0002] Polyester fiber is a fiber-forming polymer made from purified terephthalic acid (PTA) or dimethyl terephthalate (DMT) and ethylene glycol (EG) through esterification or transesterification and polycondensation. The fiber is then melt-spun and post-processed to form fibers. The esterified product flows into a pre-polycondensation reactor under a pressure differential. Two pre-polycondensation reactors are provided. The operating pressure of the first pre-polycondensation reactor is controlled at approximately 100 mbar(A), and a liquid ring vacuum pump is used to generate the vacuum. The reaction materials flow from the first pre-polycondensation reactor to the second pre-polycondensation reactor under the influence of the liquid level and pressure differential. The operating pressure of the second pre-polycondensation reactor is controlled at approximately 10 mbar(A), and a glycol vapor jet pump and a liquid ring vacuum pump are used to generate the vacuum. The glycol vapor jet pump is shared with the post-polycondensation reactor.

[0003] The first pre-polycondensation reactor uses an independent liquid ring vacuum pump, the second pre-polycondensation reactor and the post-polycondensation reactor share a glycol steam jet pump, and the mixed gas is connected to the liquid ring vacuum pump to generate vacuum. One set of equipment is equipped with two sets of liquid ring vacuum pumps and is still in use today.

[0004] With the rapid and large-scale development of the polyester industry, the process vacuum systems include water vapor injection and ethylene glycol vapor injection. Compared with water vapor injection, ethylene glycol injection systems have relatively lower energy consumption. On the other hand, since the ethylene glycol vapor condensate is recycled and reused within the device, no wastewater is discharged. However, both systems operate two sets of liquid ring vacuum pumps (the first pre-polycondensation reactor vacuum system and the second pre-polycondensation reactor vacuum system, combined with the post-polycondensation reactor vacuum system), resulting in relatively high power consumption. The use of vacuum break control, which is equivalent to the traditional control method, results in high consumption of high-temperature EG steam. Utility Model Content

[0005] In order to solve the above technical deficiencies, the utility model provides an esterification vacuum device, which can use the esterification tail gas for a vacuum jet pump to reduce the evaporation amount of ethylene glycol and lower energy consumption.

[0006] The utility model discloses an esterification vacuum device, comprising a first-stage jet pump, a second-stage jet pump A, a second-stage jet pump B, and a third-stage jet pump, and also comprising a pre-condensation tail gas pipe, a mid-condensation tail gas pipe, and a final condensation tail gas pipe. The pre-condensation tail gas pipe is connected to a tail gas pretreatment tank, the tail gas pretreatment tank is connected to a compressor through a pipeline, the compressor is connected to a tail gas mixing heat exchanger through a pipeline, an ethylene glycol supplementary pipe is provided on the tail gas mixing heat exchanger, and the mixed tail gas delivery pipe of the tail gas mixing heat exchanger is respectively connected to the first-stage jet pump and the second-stage jet pump. A, a secondary jet pump B, and a tertiary jet pump. The final polycondensation tail gas pipe is connected to the primary jet pump, the primary jet pump is connected to the first spray condenser, the top of the first spray condenser is connected to the secondary jet pump A through a pipeline, the intermediate polycondensation tail gas pipe is connected to the secondary jet pump B, the secondary jet pump A and the secondary jet pump B are both connected to the second spray condenser, the top of the second spray condenser is connected to the third jet pump through a pipeline, the third jet pump is connected to the third spray condenser, and the top of the third spray condenser is connected to the pre-polycondensation tail gas pipe through a pipeline.

[0007] Nozzles are arranged in the first spray condenser, the second spray condenser and the third spray condenser. The bottoms of the first spray condenser, the second spray condenser and the third spray condenser are connected to the ethylene glycol sealing tank through pipes. The bottoms of the ethylene glycol sealing tank are connected to an ethylene glycol circulation pump through pipes. The outlets of the ethylene glycol circulation pump are respectively connected to the interiors of the tops of the first spray condenser, the second spray condenser and the third spray condenser through pipes and are connected to the nozzles.

[0008] A liquid ring vacuum pump is provided on the pre-condensation tail gas pipe, the liquid ring vacuum pump is connected to the ethylene glycol overflow tank, an ethylene glycol cooler is provided on the ethylene glycol overflow tank, and a tail gas exhaust pipe is provided on the ethylene glycol overflow tank.

[0009] Flow regulating valves are provided on the mixed exhaust gas delivery pipes of the first-stage jet pump, the second-stage jet pump A, the second-stage jet pump B, and the third-stage jet pump.

[0010] The tail gas pretreatment tank is used to remove PTA powder from the tail gas, specifically using a fully automatic EG flushing device or a semi-automatic EG flushing device. The fully automatic EG flushing device and the semi-automatic EG flushing device are both existing known devices, and their specific structures are not described in detail here.

[0011] The esterification vacuum device obtained by the utility model introduces the pre-condensation tail gas, the intermediate condensation tail gas and the final condensation tail gas into the corresponding jet pumps at each level, thereby reducing the use of EG steam, greatly reducing energy consumption and achieving high energy utilization rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a structural diagram of the present utility model. DETAILED DESCRIPTION

[0013] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the utility model, the following is a detailed description of the specific implementation method, structure, characteristics and effects of the present invention in combination with the accompanying drawings and preferred embodiments.

[0014] Example 1:

[0015] like Figure 1 As shown, the utility model discloses an esterification vacuum device, including a first-stage jet pump 9, a second-stage jet pump A10, a second-stage jet pump B11, and a third-stage jet pump 12, and also includes a pre-condensation tail gas pipe 1, a mid-condensation tail gas pipe 8, and a final condensation tail gas pipe 7. The pre-condensation tail gas pipe 1 is connected to a tail gas pretreatment tank 2, and the tail gas pretreatment tank 2 is connected to a compressor 3 through a pipeline. The compressor 3 is connected to a tail gas mixing heat exchanger 4 through a pipeline. An ethylene glycol supplementary pipe 5 is provided on the tail gas mixing heat exchanger 4. The mixed tail gas delivery pipe 6 of the tail gas mixing heat exchanger 4 is respectively connected to the first-stage jet pump 9, the second-stage jet pump A10, the second-stage jet pump B11, and the third-stage jet pump 12. Jet pump B11, three-stage jet pump 12, the final polycondensation tail gas pipe 7 is connected to the first-stage jet pump 9, the first-stage jet pump 9 is connected to the first spray condenser 13, the top of the first spray condenser 13 is connected to the second-stage jet pump A10 through a pipeline, the intermediate polycondensation tail gas pipe 8 is connected to the second-stage jet pump B11, the second-stage jet pump A10 and the second-stage jet pump B11 are both connected to the second spray condenser 14, the top of the second spray condenser 14 is connected to the three-stage jet pump 12 through a pipeline, the three-stage jet pump 12 is connected to the third spray condenser 15, and the top of the third spray condenser 15 is connected to the pre-polycondensation tail gas pipe 1 through a pipeline.

[0016] The tail gas pretreatment tank 2 is used to remove the PTA powder in the tail gas, specifically using a fully automatic EG flushing device or a semi-automatic EG flushing device. The fully automatic EG flushing device and the semi-automatic EG flushing device are both existing known devices, and their specific structures are not described in detail.

[0017] In actual use, the pre-condensation tail gas first enters the tail gas pretreatment tank 2 for flushing, removing the PTA powder, and collecting the PTA powder. The treated and purified tail gas then enters the compressor 3 for supercharging. After supercharging, it enters the tail gas mixing heat exchanger 4, where it is mixed with the ethylene glycol entering the tail gas mixing heat exchanger 4 and heated to form a high-temperature, high-pressure mixed tail gas. The mixed tail gas enters the first-stage jet pump 9, the second-stage jet pump A10, the second-stage jet pump B11, and the third-stage jet pump 12 respectively. During the operation of the first-stage jet pump 9, it draws in the final polycondensation tail gas. When the second-stage jet pump A10 is operating, it draws in the tail gas from the top of the first spray condenser 13. When the second-stage jet pump B11 is operating, it draws in the intermediate polycondensation tail gas. When the third-stage jet pump 12 is operating, it draws in the tail gas from the second spray condenser 14. The tail gas from the third spray condenser 15, together with the pre-condensation tail gas, enters the tail gas pretreatment tank 2, achieving tail gas recycling. In this process, high-temperature tail gas can be effectively used to replace a portion of ethylene glycol vapor, thereby reducing the amount of ethylene glycol used, reducing the energy consumed by evaporation of ethylene glycol, and reducing energy consumption.

[0018] Nozzles are arranged in the first spray condenser 13, the second spray condenser 14 and the third spray condenser 15. The bottoms of the first spray condenser 13, the second spray condenser 14 and the third spray condenser 15 are connected to the ethylene glycol sealing tank 17 through pipes. The bottom of the ethylene glycol sealing tank 17 is connected to an ethylene glycol circulation pump 18 through a pipe. The outlets of the ethylene glycol circulation pump 18 are respectively connected to the interiors of the tops of the first spray condenser 13, the second spray condenser 14 and the third spray condenser 15 through pipes and are connected to the nozzles.

[0019] Since ethylene glycol vapor enters the first-stage jet pump 9, the second-stage jet pump A10, the second-stage jet pump B11, and the third-stage jet pump 12 during operation, ethylene glycol is sprayed in the first spray condenser 13, the second spray condenser 14, and the third spray condenser 15 to condense the ethylene glycol vapor, and the ethylene glycol can be directly recovered without separation, which has a better effect.

[0020] A liquid ring vacuum pump 19 is provided on the pre-condensation tail gas pipe 1, and the liquid ring vacuum pump 19 is connected to an ethylene glycol overflow tank 20, an ethylene glycol cooler 21 is provided on the ethylene glycol overflow tank 20, and an exhaust gas exhaust pipe 22 is provided on the ethylene glycol overflow tank 20. In actual use, since the first-stage jet pump 9 and the second-stage jet pump B11 will inhale the final condensation tail gas and the intermediate condensation tail gas, and the system is also continuously replenished with pre-condensation tail gas, the amount of tail gas mixed with the pre-condensation tail gas output by the third spray condenser 15 is greater than the system's requirements, so a liquid ring vacuum pump 19 is used to absorb part of the tail gas, and condense it in the ethylene glycol overflow tank 20, and then empty it after recovering the ethylene glycol. The ethylene glycol overflow tank 20 and the ethylene glycol cooler 21 are both existing known equipment and known connections, and the specific structure is not described in detail.

[0021] A flow regulating valve 16 is provided on the mixed exhaust gas delivery pipe 6 of the first-stage jet pump 9 , the second-stage jet pump A10 , the second-stage jet pump B11 , and the third-stage jet pump 12 .

[0022] Currently, the industry generally uses a method of inputting excessive mixed tail gas into the first-stage jet pump 9, the second-stage jet pump A10, the second-stage jet pump B11, and the third-stage jet pump 12 to create a vacuum greater than the required vacuum. Within the larger vacuum, an appropriate amount of ethylene glycol vapor or tail gas is then input to adjust the vacuum to the appropriate level. This method results in significant energy waste. Therefore, the present application employs a flow control valve 16 provided on the mixed tail gas delivery pipe 6 of the first-stage jet pump 9, the second-stage jet pump A10, the second-stage jet pump B11, and the third-stage jet pump 12. This valve adjusts the amount of mixed tail gas entering the corresponding jet pump according to actual demand, allowing for direct output of the desired vacuum and reducing energy consumption.

[0023] In the description of the present application, 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" 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 application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot 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 one or more of the features. In the description of the present application, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0024] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to mechanical connections; they may refer to direct connections or indirect connections through an intermediate medium; and they may refer to the interaction between two elements. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0025] In this application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0026] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simplified modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. An esterification vacuum device, comprising a first-stage jet pump, a second-stage jet pump A, a second-stage jet pump B, and a third-stage jet pump, characterized in that: It also includes a pre-condensation tail gas pipe, a mid-condensation tail gas pipe, and a final condensation tail gas pipe. The pre-condensation tail gas pipe is connected to a tail gas pretreatment tank, the tail gas pretreatment tank is connected to a compressor through a pipeline, the compressor is connected to a tail gas mixing heat exchanger through a pipeline, an ethylene glycol supplementary pipe is provided on the tail gas mixing heat exchanger, and the mixed tail gas delivery pipes of the tail gas mixing heat exchanger are respectively connected to a first-stage jet pump, a second-stage jet pump A, a second-stage jet pump B, and a third-stage jet pump. The final condensation tail gas pipe is connected to a first-stage jet pump, the first-stage jet pump is connected to a first spray condenser, and the top of the first spray condenser is connected to a second-stage jet pump A through a pipeline. The mid-condensation tail gas pipe is connected to a second-stage jet pump B, and the second-stage jet pump A and the second-stage jet pump B are both connected to a second spray condenser. The top of the second spray condenser is connected to a third-stage jet pump through a pipeline, and the third-stage jet pump is connected to a third spray condenser. The top of the third spray condenser is connected to the pre-condensation tail gas pipe through a pipeline.

2. The esterification vacuum device according to claim 1, characterized in that: Nozzles are arranged in the first spray condenser, the second spray condenser and the third spray condenser. The bottoms of the first spray condenser, the second spray condenser and the third spray condenser are connected to the ethylene glycol sealing tank through pipes. The bottoms of the ethylene glycol sealing tank are connected to an ethylene glycol circulation pump through pipes. The outlets of the ethylene glycol circulation pump are respectively connected to the interiors of the tops of the first spray condenser, the second spray condenser and the third spray condenser through pipes and are connected to the nozzles.

3. The esterification vacuum device according to claim 1, characterized in that: A liquid ring vacuum pump is provided on the pre-condensation tail gas pipe, the liquid ring vacuum pump is connected to the ethylene glycol overflow tank, an ethylene glycol cooler is provided on the ethylene glycol overflow tank, and a tail gas exhaust pipe is provided on the ethylene glycol overflow tank.

4. An esterification vacuum device according to claim 1, characterized in that: Flow regulating valves are provided on the mixed exhaust gas delivery pipes on the first-stage jet pump, the second-stage jet pump A, the second-stage jet pump B and the third-stage jet pump.

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