Online cleaning device for esterification kettle liquid level meter

Abstract

The utility model discloses an esterification kettle liquid level meter on -line cleaning device, the top exhaust of esterification reaction kettle is connected with process valve and gas phase pipe, and the bottom lateral wall of esterification reaction kettle is equipped with high pressure side sensor and is connected with the high pressure side port of differential pressure transmitter through high pressure signal pipe, and the upper end export of gas phase pipe is connected with the upper lateral wall entrance of cleaning jar, and the lower lateral wall of cleaning jar is equipped with low pressure side sensor and is connected with the low pressure side port of differential pressure transmitter through low pressure signal pipe, the top lateral wall of cleaning jar is connected with high temperature EG pipeline through EG import valve, and the inner chamber of cleaning jar is equipped with the scraper that carries out the cleaning to inner wall, and the bottom of cleaning jar is equipped with the hopper, and the hopper bottom export is connected with the lower bypass of gas phase pipe through the drain pipe and drain valve. The device can clean the dirt on low pressure sensor diaphragm on -line without influencing normal production, keeps the cleaning of low pressure side diaphragm, makes liquid level determination more accurate and reliable, and ensures the continuous stable operation of production line.

Description

Technical Field

[0001] This utility model relates to an esterification reactor level gauge, and more particularly to an online cleaning device for the esterification reactor level gauge, belonging to the field of level gauge technology. Background Technology

[0002] A polyester plant that produces ethylene glycol diformate using terephthalic acid (or dimethyl terephthalate) and ethylene glycol as raw materials includes systems for raw material conveying, slurry preparation, additive formulation, esterification (or transesterification), polycondensation, slicing, and subsequent melt conveying. In this process, the reactants are slurried and added to the esterification reactor in a specific ratio, followed by a catalyst. The reaction system is then heated to a set temperature using a heating system, while a stirring device is activated to ensure thorough mixing of the reactants. Under the action of the catalyst, the raw materials undergo a transesterification reaction, producing ester and water. During the esterification process, accurate monitoring of the working liquid level within the reactor is crucial to ensure the smooth progress of the reaction and the safety of the production line.

[0003] The operating conditions of the esterification reactor are as follows: the material temperature is 250~270℃, the reactor jacket temperature is 280~320℃, it is equipped with a stirring mechanism, the reactor is equipped with a coil heating, the reactor is a pressure vessel, the material will solidify when it cools down, and ethylene glycol vapor is an explosive and dangerous gas.

[0004] Under the above high-temperature conditions, many commonly used level transmitters were ruled out, such as those where materials could not be discharged, were prone to solidification, or carbonized; level transmitters that were not heat-resistant were also unusable. For many years, the commonly used configuration for esterification reactors was a differential pressure level gauge, which calculated the liquid level height of the esterification reactor based on the pressure difference between the high-pressure and low-pressure sides of the level gauge. However, during the stirring process in the esterification reactor, some slurry splashed onto the reactor wall and the diaphragm on the low-pressure side, and the vapor generated by the esterification reaction also evaporated upwards and adhered to the diaphragm. Over time, more and more material adhered, which caused the liquid level display to drift and become distorted. Because the maintenance time of continuous polyester units is long, the losses from stopping for inspection are huge. Therefore, the liquid level can only be calibrated frequently using a manual handheld device or cross-verified with other level gauges. Over time, the deviation of the actual liquid level gauge becomes larger and larger, even leading to emptying or overflowing of the esterification reactor, resulting in production accidents and huge economic losses or personal risks. During a parking inspection, a layer of adhesive material was found on the low-pressure side diaphragm, which is the main cause of the above problems.

[0005] Currently, most esterification reactors use purge-type level gauges. The high-pressure side pressure guide pipe extends to the bottom of the liquid level, while the low-pressure side pressure guide pipe is located above the liquid level. Nitrogen gas is introduced for purging. When the nitrogen escapes from the pressure guide pipe, the gas pressure inside the pipe balances with the static pressure of the liquid column. The pressure value measured by the pressure transmitter at this point is the liquid level. This type of level gauge is the mainstream configuration for esterification reactors. However, it is crucial to ensure that the nitrogen supply is uninterrupted. If the gas supply is interrupted, the liquid in the reactor will backflow into the pressure guide pipe. Because the pressure guide pipe is thin and long, the liquid will quickly solidify, causing blockage and rendering the level gauge unusable, making maintenance and cleaning difficult.

[0006] A very small number of esterification reactors use internal float level gauges. These level gauges have an even shorter service life because the steam generated by the esterification reaction and the material carried by the stirring will adhere to the chain of the float and condense into lumps, extending all the way to the top of the chain. The longer the time, the larger the condensation becomes, eventually causing the sensor to fail. Furthermore, because the maintenance cycle of continuous production equipment is long and it is impossible to stop and maintain it in time, this type of level gauge is gradually being phased out.

[0007] Chinese utility model patent CN202576317U discloses an "online flushing device for vacuum pipelines in a three-reactor polyester unit," which is a similar product in structure. The disclosed vacuum pipeline cleaning scheme for polyester units targets metal pipelines, involves high flushing pressure, and is prone to impact, making it unsuitable for cleaning pressure-sensitive diaphragms of sensors. Furthermore, the esterification reactor is a pressure vessel; it cannot be opened during normal production. Forcibly opening it would release ethylene glycol vapor at temperatures reaching 260°C, posing a risk to personnel. Ethylene glycol vapor is also an explosive gas with a flash point of 111°C, which could cause an explosion upon contact with an ignition source. Therefore, this technical solution cannot be used in esterification reactors. Utility Model Content

[0008] The purpose of this invention is to overcome the long-standing problem of level detection drift and instability in differential pressure flange level gauges for esterification reactors, and to provide an online cleaning device for esterification reactor level gauges. This device can clean the dirt on the diaphragm of the low-pressure sensor online without affecting normal production, keeping the diaphragm on the low-pressure side clean, making the level measurement more accurate and reliable, and ensuring the continuous and stable operation of the production line.

[0009] To solve the above technical problems, this utility model provides an online cleaning device for an esterification reactor level gauge, comprising an esterification reactor. The top exhaust port of the esterification reactor is connected to a process valve and a gas phase pipe. A high-pressure side sensor is installed on the bottom side wall of the esterification reactor and connected to the high-pressure side port of a differential pressure transmitter via a high-pressure signal pipe. The upper outlet of the gas phase pipe is connected to the upper side wall inlet of a cleaning tank. A low-pressure side sensor is installed on the lower side wall of the cleaning tank and connected to the low-pressure side port of the differential pressure transmitter via a low-pressure signal pipe. The top side wall of the cleaning tank is connected to a high-temperature EG pipeline via an EG inlet valve. The inner cavity of the cleaning tank is equipped with a scraper for cleaning the inner wall. The bottom of the cleaning tank is equipped with a cleaning tank cone, and the bottom outlet of the cleaning tank cone is connected to the lower bypass port of the gas phase pipe via a discharge pipe and a discharge valve.

[0010] Furthermore, the scraper is circular in shape and matches the cross-section of the cleaning tank. A cylinder is installed on the top of the cleaning tank, and the piston rod of the cylinder is inserted downward into the cleaning tank and connected to the center of the scraper.

[0011] Furthermore, the scraper is uniformly provided with multiple hollowed-out through holes.

[0012] Furthermore, the outlet of the compressed air source pipe is connected to the P port of the solenoid directional valve through a pressure reducing valve. The solenoid directional valve is a two-position five-way solenoid directional valve. The A port of the solenoid directional valve is connected to the upper chamber air port of the cylinder, and the B port of the solenoid directional valve is connected to the lower chamber air port of the cylinder.

[0013] Furthermore, the esterification reactor is equipped with a control box, which contains five parallel control branches: in the first control branch, the normally closed contact of the second intermediate relay is connected in series with the coil of the first time relay; in the second control branch, the delayed-open normally closed contact of the first time relay is connected in series with the coil of the first intermediate relay; in the third control branch, the coils of the second intermediate relay and the second time relay are connected in parallel, and then connected in series with the delayed-closing normally open contact of the first time relay and the delayed-open normally closed contact of the second time relay; in the fourth control branch, the normally closed contact of the second intermediate relay, the normally open contact of the first intermediate relay, and the coil of the solenoid directional valve are connected in series; and the fifth control branch is the coil of the discharge valve.

[0014] Furthermore, the first to fifth control branches are all connected in series with the remote control normally open contact.

[0015] Furthermore, the fifth control branch also includes the coil of the third intermediate relay and the coil of the third time relay connected in parallel with the coil of the discharge valve; the control power supplies are also connected in parallel with the sixth and seventh control branches. In the sixth control branch, the time-delayed normally open contact of the third time relay, the normally open contact of the third intermediate relay, and the coil of the fourth intermediate relay are connected in series in sequence. The first normally open contact of the fourth intermediate relay and the normally open contact of the third intermediate relay are connected in parallel to form a self-holding circuit. In the seventh control branch, the second normally open contact of the fourth intermediate relay is connected in series with the coil of the EG inlet valve.

[0016] Compared with the prior art, the present invention has achieved the following beneficial effects: 1. It eliminates the deviation of liquid level, making the monitoring more accurate and ensuring the stable production of the device;

[0017] 2. A cleaning tank was added to seal the liquid level, which isolates the pressure-sensitive diaphragm from the process gas, preventing the material from directly contacting the diaphragm and reducing the failure rate;

[0018] 3. The membrane can be automatically cleaned using program control, avoiding the tediousness of manual operation;

[0019] 4. It can be disassembled online, and if there is a malfunction, it will not affect the operation of the entire device, thus maintaining the stability of the continuous production line;

[0020] 5. Modifying existing EG pipelines is simple, convenient, and requires less space and has a lower investment cost. Attached Figure Description

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The drawings are provided for reference and illustration only and are not intended to limit the present invention.

[0022] Figure 1 This is a flowchart of the online cleaning device for the esterification reactor level gauge of this utility model;

[0023] Figure 2 This is a top view of the scraper in this utility model;

[0024] Figure 3 This is a diagram of the control system in this utility model;

[0025] The diagram shows: 1. Esterification reactor; 2. Stirrer; 3. Process valve; 4. Gas phase pipe; 5. Cleaning tank; 6. High-temperature EG pipeline; 7. Compressed air source pipe; 8. Pressure reducing valve; 9. Cylinder; 10. Scraper; 11. Low-pressure side sensor; 12. High-pressure side sensor; 13. Differential pressure transmitter; 14. Control box.

[0026] SV1. Solenoid directional valve; SV2. Discharge valve; SV3. EG inlet valve.

[0027] QF1. Circuit breaker; LK. Remote control normally open contact;

[0028] KA1. First intermediate relay; KA2. Second intermediate relay; KA3. Third intermediate relay; KA4. Fourth intermediate relay;

[0029] KT1. First time relay; KT2. Second time relay; KT3. Third time relay. Detailed Implementation

[0030] In the following description of this utility model, the terms "upper", "lower", "front", "rear", "left", "right", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not mean that the device must have a specific orientation.

[0031] To make the technical means, creative features, objectives and effects of this utility model easier to understand, the following description, in conjunction with specific illustrations, further elaborates on this utility model.

[0032] 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 this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0033] like Figure 1 As shown, the online cleaning device for the esterification reactor level gauge of this utility model includes an esterification reactor 1, a stirrer 2 is provided along the axis of the esterification reactor 1, a process valve 3 and a gas phase pipe 4 are connected to the exhaust port at the top of the esterification reactor 1. Since the steam temperature can reach 270℃, the process valve 3 must be heat resistant. A high-pressure side sensor 12 is provided on the bottom side wall of the esterification reactor 1 and is connected to the high-pressure side port of the pressure transmitter through a high-pressure signal pipe. The outlet of the gas phase pipe 4 is connected to the inlet of the upper side wall of the cleaning tank 5. A low-pressure side sensor 11 is provided on the lower side wall of the cleaning tank 5 and is connected to the low-pressure side port of the pressure transmitter through a low-pressure signal pipe.

[0034] The inner cavity of the cleaning tank 5 is equipped with a scraper 10 for cleaning the inner wall. The bottom of the cleaning tank 5 is equipped with a cleaning tank cone. The bottom outlet of the cleaning tank cone is connected to the lower bypass port of the gas phase pipe 4 through a discharge pipe and a discharge valve.

[0035] like Figure 2 As shown, the scraper 10 is circular, matching the cross-section of the cleaning tank 5. A cylinder 9 is mounted on the top of the cleaning tank 5, and the piston rod of the cylinder 9 is inserted downward into the cleaning tank 5 and connected to the center of the scraper 10. The scraper 10 has four evenly distributed circular holes to facilitate the flow and scouring of liquid and prevent excessive material from generating excessive pressure.

[0036] The outlet of the compressed air source pipe 7 is connected to the P port of the solenoid directional valve through the pressure reducing valve 8. The solenoid directional valve is a two-position five-way solenoid directional valve. The A port of the solenoid directional valve is connected to the upper chamber air port of the cylinder 9, and the B port of the solenoid directional valve is connected to the lower chamber air port of the cylinder 9.

[0037] Over time, turbid esterified material will accumulate in cleaning tank 5. The bottom of the cleaning tank is designed with a 60° conical bottom to facilitate the deposition of denser substances. The outlet of the conical bottom is connected to the lower end of the gas phase pipe 4 via a discharge pipe and discharge valve. During automatic cleaning, the discharge pipe discharges the turbid material through discharge valve SV2 into the esterification reactor 1. The outlet of discharge valve SV2 is connected to the gas phase pipe 4, and the connection is made by welding. Most of the esterified material will accumulate at the bottom, which can be removed by the operator simply running the cleaning program periodically.

[0038] The esterification reactor 1 is equipped with a high-temperature EG delivery pipeline to add high-temperature EG. A high-temperature EG pipe 6 is led from this pipeline to the cleaning tank 5, and connected to the top side wall of the cleaning tank 5 through the EG inlet valve. The interface of the high-temperature EG pipe 6 is located above the interface of the gas phase pipe 4. When the EG is full, the liquid will automatically overflow back to the esterification reactor 1 from the gas phase pipe 4, at which point the EG inlet valve SV3 is closed.

[0039] During normal operation, steam inside the esterification reactor 1 enters the cleaning tank 5 through the vapor phase pipe 4. When the steam pressure changes, the diaphragm of the low-pressure side sensor 11 senses the corresponding pressure. The process steam from the vapor phase pipe 4 is isolated by the high-temperature EG and the diaphragm of the low-pressure side sensor 11. The pressure of the esterification reactor 1 is conducted through the high-temperature EG, and the steam does not affect the diaphragm of the low-pressure side sensor 11. The cleaning tank 5 is connected to the esterification reactor 1 through the vapor phase pipe 4, without any other pressure relief ports or outlets. This ensures that the pressure in the upper part of the cleaning tank 5 and the esterification reactor 1 is basically the same and remains balanced. The amount of steam entering the cleaning tank 5 is also less. The esterified products brought by the steam will be in a molten state when they encounter the high-temperature EG, and will not affect the diaphragm of the low-pressure side sensor 11. Due to the decrease in temperature, a very small amount of the steam coming from the vapor phase pipe 4 will condense into liquid. Since the cleaning tank 5 is in an overflow state, the excess liquid will flow back to the esterification reactor 1 through the vapor phase pipe 4 due to gravity.

[0040] During cleaning, the exhaust valve SV2 and the EG inlet valve SV3 are opened. Simultaneously, the solenoid directional valve SV1 is activated, driving the piston rod of cylinder 9 to extend and drive the scraper 10 downward. After reaching the bottom, cylinder 9 then drives the scraper 10 upward, completing one cleaning cycle. This process can be repeated three to five times. After completion, the exhaust valve SV2 is closed first, and the EG inlet valve SV3 is closed after a 5-second delay. The entire cleaning process is then complete. The entire cleaning process is automatically completed through the control box 14 without manual intervention.

[0041] During normal operation, process steam enters the cleaning tank 5 through process valve 3 and vapor phase pipe 4. As the temperature decreases, a small amount of condensate will be generated. Since the cleaning tank 5 is already filled with high-temperature EG, excess condensate will automatically overflow through vapor phase pipe 4, maintaining a constant liquid level in the cleaning tank 5. This means the static pressure of the low-pressure side sensor 11 remains constant. As the liquid level in the esterification reactor 1 is adjusted, the pressure of the high-pressure side sensor 12 also changes accordingly. The actual liquid level value is obtained through the differential pressure transmitter 13. Over time, denser esterified substances will gradually remain in the cleaning tank 5, requiring periodic cleaning and drainage.

[0042] like Figure 3 As shown, there are seven control branches between the control power supplies. The first to fifth control branches are connected in parallel and in series below the remote control normally open contact LK. The sixth and seventh control branches are directly connected between the control power supplies.

[0043] The five control branches at the lower end of the normally open remote control contact LK are as follows:

[0044] In the first control branch, the normally closed contact of the second intermediate relay KA2 is connected in series with the coil of the first time relay KT1; in the second control branch, the time-delayed open normally closed contact of the first time relay KT1 is connected in series with the coil of the first intermediate relay KA1; in the third control branch, the coils of the second intermediate relay KA2 and the second time relay KT2 are connected in parallel, and then connected in series with the time-delayed closed normally open contact of the first time relay KT1 and the time-delayed open normally closed contact of the second time relay KT2; in the fourth control branch, the normally closed contact of the second intermediate relay KA2 and the normally open contact of the first intermediate relay KA1 are connected in series with the coil of the solenoid directional valve SV1; the fifth control branch consists of the coils of the discharge valve SV2, the coil of the third intermediate relay KA3, and the coil of the third time relay KT3 connected in parallel. All five control branches are controlled by the remote normally open contact LK.

[0045] In the sixth control branch between control power supplies, the time-delayed normally open contact of the third time relay KT3, the normally open contact of the third intermediate relay KA3, and the coil of the fourth intermediate relay KA4 are connected in series. The self-holding normally open contact of the fourth intermediate relay KA4 is connected in parallel with the normally open contact of the third intermediate relay KA3.

[0046] In the seventh control branch between control power supplies, another normally open contact of the fourth intermediate relay KA4 is connected in series with the coil of the EG inlet valve SV3.

[0047] When automatic cleaning is required, closing the air switch QF1 activates the DCS system, sending a remote start signal to initiate the control circuit. The remote control normally open contact LK closes, energizing the coil of the third intermediate relay KA3 in control box 14, causing its normally open contact to close. Simultaneously, the coil of the third time relay KT3 is also energized, causing its delayed-open normally open contact to close, driving the coil of the fourth intermediate relay KA4 to close its normally open contact. This completes the self-locking circuit of the fourth intermediate relay KA4 coil. If the normally open contact of the third intermediate relay KA3 subsequently opens, it will not affect the energization of the fourth intermediate relay KA4 coil. At this time, the closing of the normally open contact of the fourth intermediate relay KA4 energizes and opens the coil of the EG inlet valve SV3; while the coil of the exhaust valve SV2, lacking a logical locking condition, is energized with the closing of the remote control normally open contact LK, causing the exhaust valve SV2 to open instantaneously.

[0048] Simultaneously, with the remote control normally open contact LK closed, energizing the control branch, the coil of the second intermediate relay KA2 is de-energized, and its normally closed contact closes, energizing the coil of the first time relay KT1. The delayed-open normally closed contact of the first time relay KT1 remains energized for a predetermined 3-second (time can be flexibly adjusted) period, keeping the coil of the first intermediate relay KA1 energized for the predetermined time, causing the normally open contact of the first intermediate relay KA1 to close, thereby driving the coil of the solenoid directional valve SV1 to remain energized. At this time, the P port of the solenoid directional valve SV1 is connected to the A port, compressed air enters the upper chamber of the cylinder 9, and exhausts from the lower chamber through the B port. The piston rod of the cylinder 9 extends, driving the scraper 10 to move downwards.

[0049] When the first time relay KT1 reaches the predetermined time, for example, 3 seconds, its delayed disconnect normally closed contact opens, causing the coil of the first intermediate relay KA1 to be de-energized and its normally open contact to open, causing the coil of the solenoid directional valve SV1 to be de-energized. At this time, the spool valve of the solenoid directional valve SV1 is reset under the action of the spring, making the P port connected to the B port. Compressed air enters the lower chamber of the cylinder 9, and the upper chamber is exhausted through the A port. The piston rod of the cylinder 9 retracts and drives the scraper 10 to move upward.

[0050] At the same time that the first time relay KT1 reaches its predetermined time, its delayed-closing normally open contact closes, energizing both the coils of the second intermediate relay KA2 and the second time relay KT2. At this point, the second time relay KT2 begins timing. When the predetermined time is reached, the time can be set to 5 seconds (flexibly adjustable). After 5 seconds, the delayed-opening normally closed contact of the second time relay KT2 opens, simultaneously de-energizing both the coils of the second intermediate relay KA2 and the second time relay KT2. The de-energized coil of the second intermediate relay KA2 conducts... This causes the normally closed contact to close, thereby re-energizing the coil of the first time relay KT1. The delayed disconnection of the normally closed contact of the first time relay KT1 keeps the coil of the first intermediate relay KA1 energized for the originally predetermined 3-second timing period. The closing of the normally open contact of the first intermediate relay KA1 re-energizes the coil of the solenoid reversing valve SV1, and the compressed air re-enters the upper chamber of the cylinder 9. The piston rod of the cylinder 9 extends and drives the scraper 10 to move downward, thus starting a new cycle of scraper movement. In this way, the scraper 10 can move up and down three to five times.

[0051] After a certain cleaning time, the cleaning program is stopped. The DCS system sends a remote stop signal, and the remote control normally open contact LK is opened. At this time, the coils of the solenoid directional valve SV1 and the exhaust valve SV2 are de-energized due to the loss of power in the control branch, which drives the exhaust valve SV2 to close. The solenoid directional valve SV1 is reversed, that is, the P port is connected to the B port. Air enters the lower chamber of the cylinder 9 and exhausts the upper chamber through the A port. The piston rod retracts and drives the scraper 10 to reset upward.

[0052] The first time relay KT1 and the second time relay KT2 are energized delay time relays, and the third time relay KT3 is a de-energized delay time relay. When the remote control normally closed contact LK is closed, the coil of the third time relay KT3 remains energized, and its delayed-open normally open contact closes instantaneously. When the remote control normally open contact LK is open, the delayed-open normally open contact of the third time relay KT3 remains closed for a predetermined time, and then opens after the set time, thus realizing its de-energized delay function.

[0053] Because the normally closed contact LK of the remote control opens, the control branch loses power, causing the coil of the third intermediate relay KA3 to lose power and its normally open contact to open. Since the coil of the fourth intermediate relay KA4 was already in a self-locking state during the previous control steps, the normally open contact of the third intermediate relay KT3 remains closed for a predetermined time (usually set at 5 seconds, but adjustable). Because the power supply for the fourth intermediate relay KA4 is taken from the control power input, its coil remains energized for 5 seconds, and its normally open contact remains in a self-holding state, thus keeping the coil of the EG inlet valve SV3 energized and open for 5 seconds without closing. After the preset 5-second delay, the normally open contact of the third intermediate relay KT3 changes from closed to normally open, causing the coil circuit of the fourth intermediate relay KA4 to lose power, its normally open contact to open, and the coil of the EG inlet valve SV3 to close, ending the entire cleaning process. The delayed closure of the EG inlet valve SV3 ensures that the cleaning tank 5 is filled with EG, achieving the initial liquid seal state of the cleaning tank 5.

[0054] The above description is merely a preferred embodiment of the present utility model, showing and describing the basic principles, main features, and advantages of the present utility model. It is not intended to limit the scope of patent protection of the present utility model. Those skilled in the art should understand that the present utility model is not limited to the above embodiments. In addition to the above embodiments, the present utility model may have other implementations without departing from the spirit and scope of the present utility model. Various changes and improvements to the present utility model are also possible. All technical solutions formed by equivalent substitutions or equivalent transformations fall within the scope of protection claimed by the present utility model. The scope of protection claimed by the present utility model is defined by the appended claims and their equivalents. Technical features not described in the present utility model can be implemented by or using existing technology, and will not be elaborated here.

Claims

1. An online cleaning device for a liquid level gauge in an esterification reactor, comprising an esterification reactor (1), wherein a process valve (3) and a gas phase pipe (4) are connected to the top exhaust port of the esterification reactor (1), and a high-pressure side sensor (12) is provided on the bottom side wall of the esterification reactor (1) and connected to the high-pressure side port of a differential pressure transmitter (13) through a high-pressure signal pipe, characterized in that: The upper outlet of the gas phase pipe (4) is connected to the upper side wall inlet of the cleaning tank (5). The lower side wall of the cleaning tank (5) is provided with a low-pressure side sensor (11) and is connected to the low-pressure side port of the differential pressure transmitter (13) through a low-pressure signal pipe. The top side wall of the cleaning tank (5) is connected to the high-temperature EG pipeline (6) through an EG inlet valve (SV3). The inner cavity of the cleaning tank (5) is provided with a scraper (10) for cleaning the inner wall. The bottom of the cleaning tank (5) is provided with a cleaning tank cone. The bottom outlet of the cleaning tank cone is connected to the lower bypass port of the gas phase pipe (4) through a discharge pipe and a discharge valve (SV2).

2. The online cleaning device for the esterification reactor level gauge according to claim 1, characterized in that: The scraper (10) is circular and matches the cross-section of the cleaning tank (5). A cylinder (9) is installed on the top of the cleaning tank (5). The piston rod of the cylinder (9) is inserted downward into the cleaning tank (5) and connected to the center of the scraper (10).

3. The online cleaning device for the esterification reactor level gauge according to claim 2, characterized in that: The scraper (10) is provided with a plurality of hollowed-out through holes evenly distributed on it.

4. The online cleaning device for the esterification reactor level gauge according to claim 2, characterized in that: The outlet of the compressed air source pipe (7) is connected to the P port of the solenoid directional valve (SV1) through the pressure reducing valve (8). The solenoid directional valve (SV1) is a two-position five-way solenoid directional valve. The A port of the solenoid directional valve (SV1) is connected to the upper chamber air port of the cylinder (9), and the B port of the solenoid directional valve (SV1) is connected to the lower chamber air port of the cylinder (9).

5. The online cleaning device for the esterification reactor level gauge according to any one of claims 1 to 4, characterized in that, The esterification reactor (1) is equipped with a control box, which has five parallel control branches: in the first control branch, the normally closed contact of the second intermediate relay (KA2) is connected in series with the coil of the first time relay (KT1); in the second control branch, the delayed-open normally closed contact of the first time relay (KT1) is connected in series with the coil of the first intermediate relay (KA1); in the third control branch, the coil of the second intermediate relay (KA2) is connected in parallel with the coil of the second time relay (KT2), ​​and then connected in series with the delayed-closing normally open contact of the first time relay (KT1) and the delayed-open normally closed contact of the second time relay (KT2); in the fourth control branch, the normally closed contact of the second intermediate relay (KA2) and the normally open contact of the first intermediate relay (KA1) are connected in series with the coil of the solenoid reversing valve (SV1); and the fifth control branch is the coil of the discharge valve (SV2).

6. The online cleaning device for the esterification reactor level gauge according to claim 5, characterized in that, The first to fifth control branches are all connected in series with the remote control normally open contact (LK).

7. The online cleaning device for the esterification reactor level gauge according to claim 5, characterized in that, The fifth control branch also includes the coil of the third intermediate relay (KA3) and the coil of the third time relay (KT3) connected in parallel with the coil of the discharge valve (SV2); The control power supplies are also connected in parallel with a sixth and a seventh control branch. In the sixth control branch, the time-delayed normally open contact of the third time relay (KT3), the normally open contact of the third intermediate relay (KA3), and the coil of the fourth intermediate relay (KA4) are connected in series in sequence. The first normally open contact of the fourth intermediate relay (KA4) and the normally open contact of the third intermediate relay (KA3) are connected in parallel to form a self-holding circuit. In the seventh control branch, the second normally open contact of the fourth intermediate relay (KA4) is connected in series with the coil of the EG inlet valve (SV3).

Images