Device to prevent DMC distillation tower reboiler tube blockage

Abstract

The utility model discloses a device to prevent the DMC distillation tower kettle reboiler tubes from being blocked, and belongs to the field of DMC product refining production control. The device includes a forced circulation pump and a bag filter, and a set of circulation systems are connected from the U-shaped connecting pipeline between the reboiler and the distillation tower kettle. The system includes a forced circulation pump and a bag filter connected in sequence, and the tower kettle liquid is transported to the bag filter for filtration through the forced circulation pump, and the filtered high melting point compounds are recovered to the mixed alcohol tank, and the filtrate at the bag filter outlet is returned to the tower kettle for further purification. After the utility model DMC product distillation tower kettle is equipped with a forced circulation operation device, the high melting point compounds are not easy to adhere to the reboiler tubes, and after filtering through the bag filter, a part of the high melting point compounds are filtered out from the tower kettle, which not only ensures that the heavy component content in the side line extraction of the DMC product distillation tower is controlled, but also realizes the long-term operation of the reboiler.

Description

Technical Field

[0001] The utility model relates to a device for preventing high melting point compounds in a DMC distillation tower kettle from being enriched and blocking reboiler tubes, and belongs to the field of DMC product refining production control. Background Art

[0002] In the process of DMC product refining, it is necessary to ensure the qualified rate of the side-line extraction of the DMC product distillation tower, and to avoid continuous extraction of high-melting-point compounds with a large amount of DMC in the tower bottom, which would lead to waste. In order to control the cost of producing industrial-grade DMC, the DMC product distillation tower bottom adopts intermittent extraction. Intermittent extraction will cause the DMC reaction polymerization in the tower bottom of the DMC product distillation tower to produce high-melting-point compounds, which will cause the problem of clogging the reboiler tubes after long-term accumulation. Utility Model Content

[0003] In order to overcome the above-mentioned shortcomings, the utility model provides a device for preventing the high-melting-point compounds in the bottom of the DMC product distillation tower from being enriched and clogging the reboiler tubes. The bottom of the DMC product distillation tower is subjected to forced circulation operation, and the circulating liquid is treated by filtering the high-melting-point compounds, thereby ensuring that the side line extraction of the DMC product distillation tower is qualified and effectively avoiding the clogging of the reboiler under the premise of reducing the frequent intermittent extraction of the bottom material.

[0004] The utility model performs forced circulation operation on the kettle of the DMC product distillation tower to make the high melting point compound in a flowing state, and then drives the bag filter into the bag filter through a forced circulation pump to filter the high melting point compound and recover it to the mixed alcohol tank, and the circulating liquid returns to the DMC product distillation tower for further purification.

[0005] The technical scheme adopted by the utility model is: a device for preventing the blockage of the tube array of the reboiler of the DMC distillation tower kettle, comprising a circulation device and a filtering device, a set of circulation system is connected from the U-shaped connecting pipeline between the reboiler and the tower kettle of the distillation tower, the system comprises a forced circulation pump and a bag filter connected in sequence, the tower kettle liquid is transported to the bag filter for filtration through the forced circulation pump, the filtered high melting point compound is recovered to the mixed alcohol tank, and the filtrate at the outlet of the bag filter is returned to the tower kettle for further purification.

[0006] Furthermore, there are two bag filters in total, which are connected in parallel. The two filters have the same structure and serve as backup for each other.

[0007] Furthermore, the inlet pipe of the forced circulation pump is provided with a forced circulation pump inlet valve and a forced circulation pump inlet guide, and the outlet pipe is provided with a forced circulation pump outlet valve and a forced circulation pump outlet on-site pressure gauge.

[0008] Furthermore, the inlet pipe of the bag filter is provided with an inlet valve and an on-site pressure gauge, and the outlet pipe is provided with an outlet drain and an outlet valve.

[0009] Furthermore, the model of the bag filter is SC-DC-D-50, the precision is 1 μm, and the area is 0.5 ㎡.

[0010] Furthermore, the forced circulation pump is a shielded pump with a head of 50m and a flow rate of 5m³ / h.

[0011] Furthermore, the measuring range of the on-site pressure gauge is 0-1.0 MPa.

[0012] The utility model adopts a method of forced circulation of the tower bottom, and utilizes a filtering device to take out a part of the high melting point compound from the system, so that ① the heavy component content of the product taken out of the side line of the distillation tower is guaranteed; ② the distillation tower containing the high melting point compound can achieve the purpose of extending the tower bottom extraction cycle and long-term operation of the reboiler.

[0013] The device for preventing the DMC distillation tower kettle reboiler tube blockage provided by the utility model brings the following beneficial effects:

[0014] After the forced circulation operation device is added to the kettle of the DMC product distillation tower, high-melting-point compounds are not easy to adhere to the reboiler tubes. After filtering through the bag filter, a part of the high-melting-point compounds are filtered out from the kettle, which not only ensures that the content of heavy components in the side line extraction of the DMC product distillation tower can be controlled, but also realizes the long-term operation of the reboiler.

[0015] The utility model is further described below in conjunction with the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the utility model.

[0017] In the figure: 1 is a DMC product distillation tower, 2 is a reboiler of a DMC product distillation tower, 3 is an inlet valve of a forced circulation pump, 4 is an inlet guide of a forced circulation pump, 5 is a forced circulation pump, 6 is an outlet valve of a forced circulation pump, 7 is an on-site pressure gauge of an outlet of a forced circulation pump, 8 is an inlet valve of a bag filter A, 9 is an on-site pressure gauge of a bag filter A, 10 is a bag filter A, 11 is an outlet guide of a bag filter A, 12 is an outlet valve of a bag filter A, 13 is an inlet valve of a bag filter B, 14 is an on-site pressure gauge of a bag filter B, 15 is a bag filter B, 16 is an outlet guide of a bag filter B, 17 is an outlet valve of a bag filter B, and 18 is an alcohol mixing tank. DETAILED DESCRIPTION Example

[0018] like Figure 1As shown, a device for preventing the clogging of the tube array of the reboiler of the DMC distillation tower bottom comprises a circulation device and a filtering device. A U-shaped connecting pipe from the reboiler 2 of the DMC product distillation tower and the bottom of the DMC product distillation tower 1 is connected to a circulation system. The system comprises a forced circulation pump 5 and a bag filter connected in sequence. The bottom liquid is transported to the bag filter for filtration through the forced circulation pump 5. The filtered high melting point compounds are recovered to the mixed alcohol tank 18. The filtrate at the outlet of the bag filter is returned to the DMC product distillation tower 1 for further purification.

[0019] Furthermore, there are two bag filters in total, bag filter A10 and bag filter B15 connected in parallel, and the two bag filters have the same structure and serve as backup for each other.

[0020] Furthermore, the inlet pipeline of the forced circulation pump 5 is provided with a forced circulation pump inlet valve 3 and a forced circulation pump inlet drain 4, and the outlet pipeline is provided with a forced circulation pump outlet valve 6 and a forced circulation pump outlet on-site pressure gauge 7.

[0021] Furthermore, the inlet pipe of the bag filter is provided with an inlet valve and an on-site pressure gauge, and the outlet pipe is provided with an outlet drain and an outlet valve. Figure 1 As shown: the inlet pipe of bag filter A10 is provided with bag filter A inlet valve 8 and bag filter A local pressure gauge 9, and the outlet pipe is provided with bag filter A outlet guide 11 and bag filter A outlet valve 12; the inlet pipe of bag filter B15 is provided with bag filter B inlet valve 13 and bag filter B local pressure gauge 14, and the outlet pipe is provided with bag filter B outlet guide 16 and bag filter B outlet valve 17

[0022] Furthermore, the model of the bag filter is SC-DC-D-50, the precision is 1 μm, and the area is 0.5 ㎡.

[0023] Furthermore, the forced circulation pump is a shielded pump with a head of 50m and a flow rate of 5m³ / h.

[0024] Furthermore, the measuring range of the on-site pressure gauge is 0-1.0 MPa.

[0025] The operation mode of the above device is described in detail as follows:

[0026] 1. Normal commissioning process: The material containing high melting point compounds at the U-shaped connecting pipe between the DMC product distillation tower and the DMC product distillation tower reboiler is sent to the bag filter A through a forced circulation pump. After being filtered by the bag filter A, the filtrate is sent to the DMC product distillation tower kettle for further purification.

[0027] 2. Commissioning steps:

[0028] ①Open the inlet valve of the forced circulation pump;

[0029] ②Start the forced circulation pump;

[0030] ③ Slowly open the outlet valve of the forced circulation pump, the inlet valve and the outlet valve of the bag filter A;

[0031] ④ Observe the local pressure gauge at the outlet of the forced circulation pump and the local pressure gauge of bag filter A. When the pressure difference is ≥0.01MPa, cut bag filter A to bag filter B.

[0032] 3. Bag filter cutting steps:

[0033] ① Keep the forced circulation pump running and slowly open the inlet valve and outlet valve of bag filter B;

[0034] ② After ensuring that bag filter B is in normal use, close the inlet valve and outlet valve of bag filter A;

[0035] ③Open the outlet drain of bag filter A, drain the material, and then take out the built-in device to clean bag filter A;

[0036] ④After cleaning, return the bag filter A to standby use.

[0037] 4. Technical conditions

[0038] ① Bag filter A and bag filter B are connected in parallel, both models are SC-DC-D-50, and the filter bag precision of bag filter is 1 micron;

[0039] ②Bag filter A / B is equipped with a pressure detection device;

[0040] ③During the operation, it is necessary to inspect and record the local pressure at the outlet of the forced circulation pump and the pressure of the operating bag filter. When the pressure difference is ≥0.01MPa, the bag filter needs to be switched and cleaned.

[0041] In a chemical production enterprise with an annual output of 50,000 tons of industrial-grade DMC equipment, the DMC product distillation tower side line product was extracted, and high-boiling point compounds were intermittently extracted from the bottom of the tower. During operation, the DMC content in the product decreased repeatedly (as shown in Table 1), the gas phase temperature of the reboiler rose rapidly, and the bottom of the tower was intermittently extracted frequently, which led to the problem of reboiler tube blockage.

[0042] Table 1

[0043]

[0044] Table 2

[0045]

[0046] As can be seen from Table 1, under full-load operation, the tower bottom needs to be withdrawn within 4 days. The tower bottom of the DMC product distillation tower was connected to the utility model device for trial use. After commissioning, the tower bottom withdrawal time was extended to 7 days (as shown in Table 2), which proves that the utility model device extends the period of intermittent withdrawal of the tower bottom and solves the problem of reboiler tube blockage.

Claims

1. A device for preventing DMC distillation tower kettle reboiler tube blockage, characterized in that: It includes a forced circulation pump and a bag filter. A circulation system is connected from the U-shaped connecting pipe between the reboiler and the bottom of the distillation tower. The system includes a forced circulation pump and a bag filter connected in sequence. The bottom liquid is transported to the bag filter for filtration through the forced circulation pump, and the filtered high-melting point compounds are recovered to the mixing alcohol tank. The filtrate at the outlet of the bag filter is returned to the bottom of the tower for further purification.

2. The device for preventing DMC distillation tower bottom reboiler tube blockage according to claim 1, characterized in that: There are two bag filters in total, which are connected in parallel. The two filters have the same structure and serve as backup for each other.

3. The device for preventing DMC distillation tower bottom reboiler tube blockage according to claim 1, characterized in that: The inlet pipeline of the forced circulation pump is provided with a forced circulation pump inlet valve and a forced circulation pump inlet guide, and the outlet pipeline is provided with a forced circulation pump outlet valve and a forced circulation pump outlet local pressure gauge.

4. The device for preventing DMC distillation tower bottom reboiler tube blockage according to claim 3, characterized in that: The forced circulation pump is a shielded pump with a head of 50m and a flow rate of 5m³ / h.

5. The device for preventing DMC distillation tower bottom reboiler tube blockage according to claim 1, characterized in that: The inlet pipe of the bag filter is provided with an inlet valve and an on-site pressure gauge, and the outlet pipe is provided with an outlet drain and an outlet valve.

6. The device for preventing DMC distillation tower bottom reboiler tube blockage according to claim 5, characterized in that: The model of the bag filter is SC-DC-D-50, the precision is 1 μm, and the area is 0.5 m2.

7. The device for preventing DMC distillation tower bottom reboiler tube blockage according to claim 5, characterized in that: The measuring range of the on-site pressure gauge is 0-1.0 MPa.

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