Online hot flushing system for ethylene glycol liquid seal tank extraction pipeline

Abstract

The utility model discloses an on-line hot flushing system for an ethylene glycol liquid seal tank extraction pipeline, which belongs to the technical field of chemical production equipment and comprises a scraper condenser and a liquid seal tank, the scraper condenser is communicated with the liquid seal tank through a pipeline, a gas phase pipeline is arranged on the upper portion of the scraper condenser, and the lower portion of the liquid seal tank is communicated with a circulating pump through a pipeline. The circulating pump is communicated with the upper portion of the scraper condenser through an ethylene glycol spraying pipeline, a heat exchanger is arranged on the ethylene glycol spraying pipeline, a liquid level sensor is arranged on the liquid seal tank, one side of the ethylene glycol spraying pipeline is communicated with an EG storage tank through a pipeline, an adjusting valve set is installed on the pipeline, and the EG storage tank is communicated with the liquid level sensor. The number of valves of the adjusting valve group can be adjusted according to needs, the adjusting valve group is communicated with high-temperature EG of the process tower through a high-temperature ethylene glycol pipeline, the high-temperature EG of the process tower is used for flushing the adjusting valve group, high-temperature ethylene glycol can soften and dissolve scales, and normal work of adjusting valves and flow meters is kept. The method is mainly applied to chemical production.

Description

Technical Field

[0001] This utility model relates to the field of chemical production technology, and in particular to an online hot flushing system for ethylene glycol liquid seal tank outflow pipeline. Background Technology

[0002] Polyester production primarily involves the esterification reaction of diacids and diols under specific temperature, pressure, and catalyst conditions, producing polyester prepolymers which then undergo polycondensation to further polymerize into high molecular weight polymers. This process is accompanied by the formation of oligomers as a side reaction. Polycondensation is a reversible reaction; to propagate the reaction in the forward direction, it must be carried out under vacuum conditions, requiring the continuous removal of oligomers generated from the side reaction. The ethylene glycol liquid seal tank is a crucial piece of equipment in polyester production, forming a vacuum spray system together with a scraped condenser, plate heat exchanger, and ethylene glycol circulation pump.

[0003] One end of the scraped condenser is connected to the reactor via a gas phase pipeline, and the other end is connected to the vacuum pump. The bottom of the condenser enters the liquid seal tank via a large gas leg for sealing. Oligomers produced during the polycondensation reaction enter the scraped condenser via the gas phase pipeline. Ethylene glycol in the liquid seal tank is cooled by a plate heat exchanger via an ethylene glycol circulation pump and then sprayed from top to bottom at the top of the scraped condenser, carrying the oligomers into the liquid seal tank. After filtration in the liquid seal tank, the glycol is recycled, continuously capturing oligomers in the system. Continuous recycling also leads to an increase in ethylene glycol impurities in the liquid seal tank, affecting the system's vacuuming capability. Therefore, fresh ethylene glycol needs to be continuously added to the system for replacement during production. The addition of fresh ethylene glycol raises the liquid level in the liquid seal tank, which is controlled by a regulating valve on its outlet pipeline. When the level is high, the regulating valve opens wider, increasing the output; conversely, when the level is low, the valve closes.

[0004] The ethylene glycol circulating through the spray system passes through the filter baskets in the inner and outer chambers of the liquid seal tank and the pre-pump filter, which removes most of the oligomers. However, some residue remains trapped in the system. This residue circulates within the system for extended periods, forming scale on the inner walls of the pipes and affecting their transport capacity. Scale buildup is particularly noticeable at regulating valves and flow meters, causing blockages and impairing their regulating function. This, in turn, affects the level control of the ethylene glycol liquid seal tank, potentially leading to production accidents such as full tank or empty tank. Utility Model Content

[0005] The purpose of this utility model is to solve at least one of the technical problems existing in the prior art, and the technical solution adopted is as follows:

[0006] An online hot flushing system for an ethylene glycol liquid seal tank outflow pipeline includes a scraped condenser and a liquid seal tank. The scraped condenser is connected to the liquid seal tank via a pipeline and is used for material cooling. A gas phase pipeline is provided at the upper part of the scraped condenser. The lower part of the liquid seal tank is connected to a circulating pump via a pipeline. The circulating pump is connected to the upper part of the scraped condenser via a spray ethylene glycol pipeline. A heat exchanger is provided on the spray ethylene glycol pipeline. A liquid level sensor is provided on the liquid seal tank. One side of the spray ethylene glycol pipeline is connected to an EG storage tank via a pipeline. A regulating valve group is installed on the pipeline, and the number of valves in the regulating valve group can be adjusted as needed.

[0007] The core improvements of this utility model are as follows:

[0008] The control valve assembly is connected to the high-temperature EG in the process tower via a high-temperature ethylene glycol pipeline. A tower bottom pump is installed on the high-temperature ethylene glycol pipeline. The high-temperature EG in the process tower is used to flush the control valve assembly. The high-temperature ethylene glycol can soften and dissolve scale, keeping the control valve and flow meter working properly.

[0009] Preferably, the regulating valve assembly is connected to the filter via a pipeline. The filter is used to filter impurities, and the filtered ethylene glycol can be recycled. The filter is characterized in that it is a detachable structure, and is connected to the circulation pump b via a pipeline. The circulation pump b is connected to the upper part of the scraper condenser via a pipeline.

[0010] The working principle of this utility model is as follows:

[0011] Draw a pipeline from the process tower outlet pipeline to the regulating valve group of the liquid seal tank outlet pipeline, and connect it to the inlet of the corresponding regulating valve. Regularly flush the regulating valve with high-temperature ethylene glycol. Do not flush for too long to avoid the system ethylene glycol temperature from becoming too high. When flushing, filter the ethylene glycol through the filter to remove scale residue and continue to circulate it. Regularly flush the filter to achieve better filtration effect.

[0012] This utility model has the following advantages:

[0013] 1. The high-temperature ethylene glycol from the process tower is led to the regulating valve of the liquid seal tank outlet pipeline. Regular flushing can prevent the regulating valve from becoming clogged and ensure long-term operation of the equipment.

[0014] 2. Online flushing can reduce the workload of disassembling and assembling control valves. Attached Figure Description

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments;

[0016] Figure 1 This is a schematic diagram illustrating the working principle of this utility model. Detailed Implementation

[0017] This section will describe in detail the specific embodiments of the present utility model. The preferred embodiments of the present utility model are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present utility model, but they should not be construed as limiting the scope of protection of the present utility model.

[0018] like Figure 1 As shown:

[0019] An online hot flushing system for an ethylene glycol liquid seal tank outflow pipeline includes a scraped condenser 1 and a liquid seal tank 5. The scraped condenser 1 is connected to the liquid seal tank 5 via a pipeline. The lower part of the liquid seal tank 5 is connected to a circulating pump a12 via a pipeline. The circulating pump a12 is connected to the upper part of the scraped condenser 1 via a spray ethylene glycol pipeline 3. A heat exchanger 8 is installed on the spray ethylene glycol pipeline 3. A liquid level sensor 6 is installed on the liquid seal tank 5. One side of the spray ethylene glycol pipeline 3 is connected to an EG storage tank 11 via a pipeline. A regulating valve assembly 7 is installed on the pipeline.

[0020] The regulating valve group 7 is connected to the high-temperature EG of the process tower 2 through the high-temperature ethylene glycol pipeline 4; the regulating valve group 7 is connected to the filter 9 through a pipeline, the filter 9 is connected to the circulation pump b10 through a pipeline, and the circulation pump b10 is connected to the upper part of the scraped condenser 1 through a pipeline. The filter 9 is a detachable structure and has a one-on-one standby structure.

[0021] The working principle of this utility model is as follows:

[0022] The ethylene glycol temperature in the bottom of process tower 2 is approximately 170℃-180℃. The high-temperature ethylene glycol from the bottom is pumped through circulating pump b10 and transported to the regulating valve group 7 via high-temperature ethylene glycol pipeline 4 for flushing. The high-temperature ethylene glycol softens and dissolves scale, ensuring the normal operation of all valves and flow meters in the regulating valve group 7 and preventing equipment blockage. This flushing is performed periodically, depending on the blockage situation at the regulating valve group. After flushing, the high-temperature ethylene glycol is filtered through filter 9 and then re-enters the scraped condenser 1. This design ensures the safety of the liquid level control in the ethylene glycol liquid seal tank 5, preventing production accidents such as full or empty tanks.

[0023] The embodiments of the present utility model have been described in detail above with reference to the accompanying drawings. However, the present utility model is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present utility model.

Claims

1. A kind of ethylene glycol liquid seal groove production pipeline online hot flushing system, including scraper condenser (1) and liquid seal groove (5), scraper condenser (1) is connected with liquid seal groove (5) by pipeline, the lower portion of liquid seal groove (5) is connected with circulating pump a (12) by pipeline, circulating pump a (12) is connected with the upper portion of scraper condenser (1) by spraying ethylene glycol pipeline (3), heat exchanger (8) is equipped on spraying ethylene glycol pipeline (3), the liquid level sensor (6) of liquid seal groove (5) is equipped, the side of spraying ethylene glycol pipeline (3) is connected with EG storage tank (11) by pipeline, adjusting valve group (7) is installed on the pipeline, it is characterized by, adjusting valve group (7) is connected with the high temperature EG of process column (2) by high temperature ethylene glycol pipeline (4); Adjusting valve group (7) is connected with filter (9) by pipeline at place, filter (9) is connected with circulating pump b (10) by pipeline, circulating pump b (10) is connected with the upper portion of scraper condenser (1) by pipeline.

2. An ethylene glycol liquid seal groove production line on-line hot flushing system as claimed in claim 1, characterized in that, The filter (9) is of detachable structure.

3. An ethylene glycol liquid seal groove production line on-line hot flushing system as claimed in claim 1, wherein, The filter (9) is of one open and one standby structure.

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