Online cleaning system of methanol-reaction gas heat exchanger

Abstract

The utility model discloses an on-line cleaning system for methanol-reaction gas heat exchangers, which comprises two reaction gas heat exchangers, the tops of the two reaction gas heat exchangers are connected with gas inlet units, an on-line cleaning mechanism is connected between the two gas inlet units, the bottoms of the two reaction gas heat exchangers are respectively connected with a first exhaust pipe and a second exhaust pipe, and the first exhaust pipe and the second exhaust pipe are respectively connected with a gas inlet pipe and a gas outlet pipe. The ends, away from the reaction gas heat exchanger, of the first exhaust pipe and the second exhaust pipe are connected with an exhaust manifold. The methanol-reaction gas heat exchanger solves the problem of poor heat exchange effect caused by blockage of catalyst fine powder on the reaction gas side of the methanol-reaction gas heat exchanger in a methanol-to-olefin process, the temperature of a high-temperature heat exchange medium on the reaction gas side is reduced, reaction gas cooling by a subsequent water system is facilitated, the energy consumption of the device is reduced, the heat exchange efficiency of the methanol-reaction gas heat exchanger is improved, and the production cost is reduced. The temperature of the methanol-side low-temperature heat exchange medium is increased, so that the stability of the reaction system is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of methanol to olefins system, and specifically relates to an online cleaning system for a methanol-reaction gas heat exchanger. Background Art

[0002] The methanol to olefins (DMTO) unit reaction gas can effectively remove catalyst fine powder with a particle size larger than 5μm after passing through the first-stage cyclone separator, the second-stage cyclone separator and the third-stage cyclone separator, but the catalyst fine powder below 5μm is difficult to remove. Therefore, after the reaction gas carrying trace catalyst fine powder enters the tube bundle on the tube side of the methanol-reaction gas heat exchanger, the catalyst fine powder gradually adheres to and thickens on the inner wall of the tube bundle, resulting in a gradual decrease in the heat exchange effect of the methanol-reaction gas heat exchanger.

[0003] At present, since the inner wall of the reaction gas pipeline is a heat-insulating and wear-resistant lining, the inlet and outlet valves of the methanol-reaction gas heat exchanger shell cannot completely cut off the material, resulting in the inability to effectively isolate the medium of the methanol-reaction gas heat exchanger in the methanol-to-olefins process, and therefore the conditions for offline cleaning are not met. In order to increase the temperature of methanol gas, the company can only shut down the equipment and perform manual high-pressure cleaning of the methanol-reaction gas heat exchanger tube bundle; or start the heating furnace to heat up the methanol by burning a large amount of natural gas, which will cause unplanned shutdown of the device or significantly increase the operating and production costs of the device, which will have an adverse impact on the stable production and operation of the company. Utility Model Content

[0004] The utility model aims to provide an online cleaning system for a methanol-reaction gas heat exchanger, which can perform online cleaning on the methanol-reaction gas heat exchanger.

[0005] The technical solution adopted by the utility model is an online cleaning system for a methanol-reaction gas heat exchanger, comprising two reaction gas heat exchangers, the tops of the two reaction gas heat exchangers are connected with air intake units, an online cleaning mechanism is connected between the two air intake units, the bottoms of the two reaction gas heat exchangers are respectively connected with a first exhaust pipe and a second exhaust pipe, and the ends of the first exhaust pipe and the second exhaust pipe away from the reaction gas heat exchangers are connected with an exhaust main pipe.

[0006] The utility model is also characterized in that:

[0007] The pipe bodies of the first exhaust pipe and the second exhaust pipe are both connected with exhaust valves.

[0008] The air intake unit includes a first air intake pipe and a second air intake pipe, which are respectively connected to the tops of two reaction gas heat exchangers, and the ends of the first air intake pipe and the second air intake pipe away from the reaction gas heat exchangers are connected to an air intake main pipe, and an online cleaning mechanism is connected between the first air intake pipe and the second air intake pipe.

[0009] The pipe bodies of the first air intake pipe and the second air intake pipe are both connected with air intake valves, and the connection points between the online cleaning mechanism and the first air intake pipe and the second air intake pipe are respectively arranged below the two air intake valves.

[0010] The online cleaning mechanism includes a first storage tank and a second storage tank, the first storage tank and the second storage tank are connected to a nitrogen system, the bottom of the first storage tank and the second storage tank are respectively connected to a first outlet pipe and a second outlet pipe, the end of the first outlet pipe away from the first storage tank is connected to the first air inlet pipe, the end of the second outlet pipe away from the second storage tank is connected to the second air inlet pipe, and the connection point of the first outlet pipe and the first air inlet pipe and the connection point of the second outlet pipe and the second air inlet pipe are respectively arranged below the two air inlet valves.

[0011] The body of the first outlet pipe is connected to a first outlet valve and a second outlet valve, the first outlet valve is arranged close to the first storage tank, the second outlet valve is arranged close to the connection point between the first outlet pipe and the first air inlet pipe, the body of the second outlet pipe is connected to a third outlet valve and a fourth outlet valve, the third outlet valve is arranged close to the second storage tank, and the fourth outlet valve is arranged close to the connection point between the second outlet pipe and the second air inlet pipe.

[0012] The nitrogen system comprises a nitrogen main pipe, one end of which is connected to a branch pipe, both ends of which are respectively connected to a first outlet pipe and a second outlet pipe, the connection points of the branch pipe with the first outlet pipe and the second outlet pipe are respectively arranged between a first outlet valve and a second outlet valve, a third outlet valve and a fourth outlet valve, the pipe body of the branch pipe is connected to a first nitrogen pipe and a second nitrogen pipe, and ends of the first nitrogen pipe and the second nitrogen pipe away from the branch pipe are respectively connected to side walls of a first storage tank and a second storage tank.

[0013] The first nitrogen pipe and the second nitrogen pipe are arranged on both sides of the connection point between the branch pipe and the nitrogen main pipe. The pipe bodies of the first nitrogen pipe and the second nitrogen pipe are both connected with nitrogen inlet valves, and the two nitrogen inlet valves are respectively arranged close to the first storage tank and the second storage tank. The pipe body of the branch pipe is connected with a first control valve and a second control valve. The first control valve is arranged between the connection point between the branch pipe and the first outlet pipe and the connection point between the branch pipe and the first nitrogen pipe. The second control valve is arranged between the connection point between the branch pipe and the second outlet pipe and between the branch pipe and the second nitrogen pipe. The pipe body of the nitrogen main pipe is connected with a nitrogen main valve.

[0014] The tops of the first storage tank and the second storage tank are both connected with feeding pipes, and the pipe bodies of the two feeding pipes are both connected with feeding valves.

[0015] The beneficial effects of the utility model are:

[0016] The utility model discloses an online cleaning system for a methanol-reaction gas heat exchanger, which solves the problem of clogging of catalyst fine powder on the reaction gas side of the methanol-reaction gas heat exchanger in a methanol to olefin process, resulting in poor heat exchange effect. The temperature of the high-temperature heat exchange medium on the reaction gas side is reduced, which is beneficial to the subsequent water system for cooling the reaction gas, and the energy consumption of the device is reduced, thereby improving the heat exchange efficiency of the methanol-reaction gas heat exchanger, and the temperature of the low-temperature heat exchange medium on the methanol side is increased, thereby improving the stability of the reaction system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The utility model is a schematic diagram of the structure of the online cleaning system of the methanol-reaction gas heat exchanger.

[0018] In the figure: 1. reaction gas heat exchanger, 2. first exhaust pipe, 3. second exhaust pipe, 4. exhaust main pipe, 5. exhaust valve, 6. first intake pipe, 7. second intake pipe, 8. intake main pipe, 9. intake valve, 10. first storage tank, 11. second storage tank, 12. first outlet pipe, 13. second outlet pipe, 14. first outlet valve, 15. second outlet valve, 16. third outlet valve, 17. fourth outlet valve, 18. nitrogen main pipe, 19. branch pipe, 20. first nitrogen pipe, 21. nitrogen inlet valve, 22. first control valve, 23. second control valve, 24. second nitrogen pipe, 25. nitrogen main valve, 26. feed pipe, 27. feed valve. DETAILED DESCRIPTION

[0019] The utility model is described in detail below with reference to the accompanying drawings and specific implementation modes.

[0020] The utility model provides an online cleaning system for a methanol-reaction gas heat exchanger, such as Figure 1 As shown, it includes two reaction gas heat exchangers 1, the tops of the two reaction gas heat exchangers 1 are connected with air intake units, an online cleaning mechanism is connected between the two air intake units, the bottoms of the two reaction gas heat exchangers 1 are respectively connected with a first exhaust pipe 2 and a second exhaust pipe 3, and the ends of the first exhaust pipe 2 and the second exhaust pipe 3 away from the reaction gas heat exchanger 1 are connected with an exhaust main pipe 4. The high-temperature reaction gas is mixed with the calcium hydroxide particles in the online cleaning mechanism through the air intake unit and enters the two reaction gas heat exchangers 1. The calcium hydroxide particles quickly enter the reaction gas heat exchanger 1 and rub and collide with the catalyst fine powder attached to the tube wall, thereby peeling off the catalyst fine powder and realizing online cleaning of the heat exchanger. Subsequently, the catalyst fine powder and solid calcium hydroxide particles enter the exhaust main pipe 4 through the first exhaust pipe 2 and the second exhaust pipe 3 with the reaction gas, and finally enter the subsequent water system. The calcium hydroxide particles are dissolved in the water, and there is no other negative impact on the system.

[0021] Example 1

[0022] The first exhaust pipe 2 and the second exhaust pipe 3 are both connected to exhaust valves 5. The two exhaust valves 5 control the exhaust volume of the two reaction gas heat exchangers 1 respectively.

[0023] Example 2

[0024] The air intake unit includes a first air intake pipe 6 and a second air intake pipe 7, which are respectively connected to the tops of the two reaction gas heat exchangers 1, and the ends of the first air intake pipe 6 and the second air intake pipe 7 away from the reaction gas heat exchanger 1 are connected to an air intake main pipe 8, and the online cleaning mechanism is connected between the first air intake pipe 6 and the second air intake pipe 7. The high-temperature reaction gas enters the first air intake pipe 6 and the second air intake pipe 7 from the air intake main pipe 8, and then mixes with the calcium hydroxide particles in the online cleaning mechanism and enters the two reaction gas heat exchangers 1.

[0025] The first air inlet pipe 6 and the second air inlet pipe 7 are both connected to an air inlet valve 9, and the connection points between the online cleaning mechanism and the first air inlet pipe 6 and the second air inlet pipe 7 are respectively arranged below the two air inlet valves 9. The two air inlet valves 9 control the air intake of the first air inlet pipe 6 and the second air inlet pipe 7, respectively.

[0026] Example 3

[0027] The online cleaning mechanism includes a first storage tank 10 and a second storage tank 11, the first storage tank 10 and the second storage tank 11 are connected to a nitrogen system, the bottoms of the first storage tank 10 and the second storage tank 11 are respectively connected to a first outlet pipe 12 and a second outlet pipe 13, the end of the first outlet pipe 12 away from the first storage tank 10 is connected to the first air inlet pipe 6, the end of the second outlet pipe 13 away from the second storage tank 11 is connected to the second air inlet pipe 7, and the connection point of the first outlet pipe 12 and the first air inlet pipe 6 and the connection point of the second outlet pipe 13 and the second air inlet pipe 7 are respectively arranged below the two air inlet valves 9. The nitrogen system serves as a pressurizing system for the first storage tank 10 and the second storage tank 11, pressurizing the two storage tanks, and injecting the calcium hydroxide particles in the storage tanks into the first air inlet pipe 6 and the second air inlet pipe 7 using low-pressure nitrogen.

[0028] The first outlet pipe 12 is connected to a first outlet valve 14 and a second outlet valve 15, the first outlet valve 14 is arranged near the first storage tank 10, the second outlet valve 15 is arranged near the connection point between the first outlet pipe 12 and the first air inlet pipe 6, the second outlet pipe 13 is connected to a third outlet valve 16 and a fourth outlet valve 17, the third outlet valve 16 is arranged near the second storage tank 11, and the fourth outlet valve 17 is arranged near the connection point between the second outlet pipe 13 and the second air inlet pipe 7. The arrangement of the four outlet valves ensures that the nitrogen in the nitrogen system can inject the calcium hydroxide particles into the reaction gas heat exchanger 1, and the nitrogen can also be directly introduced into the reaction gas heat exchanger 1, and the corresponding outlet valves can be switched.

[0029] Example 4

[0030] The nitrogen system includes a nitrogen main pipe 18, one end of which is connected to a branch pipe 19, both ends of which are connected to the first outlet pipe 12 and the second outlet pipe 13, respectively. The connection points between the branch pipe 19 and the first outlet pipe 12 and the second outlet pipe 13 are respectively arranged between the first outlet valve 14 and the second outlet valve 15, the third outlet valve 16 and the fourth outlet valve 17. The pipe body of the branch pipe 19 is connected to the first nitrogen pipe 20 and the second nitrogen pipe 24, and the ends of the first nitrogen pipe 20 and the second nitrogen pipe 24 away from the branch pipe 19 are respectively connected to the side walls of the first storage tank 10 and the second storage tank 11. The nitrogen from the nitrogen main pipe 18 is respectively pressurized to the first storage tank 10 and the second storage tank 11 through the branch pipe 19 and the first nitrogen pipe 20 and the second nitrogen pipe 24, and the corresponding outlet valves can also be opened and closed to directly input the nitrogen from the branch pipe 19 and the first outlet pipe 12 and the second outlet pipe 13 into the two reaction gas heat exchangers 1.

[0031] The first nitrogen pipe 20 and the second nitrogen pipe 24 are arranged on both sides of the connection point between the branch pipe 19 and the nitrogen main pipe 18. The pipe bodies of the first nitrogen pipe 20 and the second nitrogen pipe 24 are both connected with nitrogen inlet valves 21, and the two nitrogen inlet valves 21 are respectively arranged close to the first storage tank 10 and the second storage tank 11. The pipe body of the branch pipe 19 is connected with a first control valve 22 and a second control valve 23. The first control valve 22 is arranged between the connection point between the branch pipe 19 and the first outlet pipe 12 and the connection point between the branch pipe 19 and the first nitrogen pipe 20. The second control valve 23 is arranged between the connection point between the branch pipe 19 and the second outlet pipe 13 and between the branch pipe 19 and the second nitrogen pipe 24. The pipe body of the nitrogen main pipe 18 is connected with a nitrogen main valve 25.

[0032] The tops of the first storage tank 10 and the second storage tank 11 are both connected with a feed pipe 26, and the bodies of the two feed pipes 26 are both connected with a feed valve 27. The calcium hydroxide particles are input into the two storage tanks from the feed pipe 26.

[0033] The working principle of the online cleaning system of the methanol-reaction gas heat exchanger of the utility model is as follows:

[0034] The high-temperature reaction gas enters the first intake pipe 6 and the second intake pipe 7 from the intake main pipe 8 respectively. The nitrogen from the nitrogen main pipe 18 passes through the branch pipe 19 and the first nitrogen pipe 20 and the second nitrogen pipe 24 to pressurize the first storage tank 10 and the second storage tank 11 respectively. The calcium hydroxide particles in the first storage tank 10 and the second storage tank 11 are injected into the reaction gas in the first intake pipe 6 and the second intake pipe 7 using low-pressure nitrogen, and the mixture enters into the two reaction gas heat exchangers 1. The calcium hydroxide particles quickly enter the reaction gas heat exchanger 1 and rub and collide with the catalyst fine powder attached to the pipe wall, thereby peeling off the catalyst fine powder and realizing online cleaning of the heat exchanger. Subsequently, the catalyst fine powder and solid calcium hydroxide particles enter the exhaust main pipe 4 with the reaction gas through the first exhaust pipe 2 and the second exhaust pipe 3 respectively, and finally enter the subsequent water system. The calcium hydroxide particles are dissolved in the water, and there is no other negative impact on the system.

[0035] The utility model discloses an online cleaning system for a methanol-reaction gas heat exchanger, which solves the problem of clogging of catalyst fine powder on the reaction gas side of the methanol-reaction gas heat exchanger in a methanol to olefin process, resulting in poor heat exchange effect. The temperature of the high-temperature heat exchange medium on the reaction gas side is reduced, which is beneficial to the subsequent water system for cooling the reaction gas, and the energy consumption of the device is reduced, thereby improving the heat exchange efficiency of the methanol-reaction gas heat exchanger, and the temperature of the low-temperature heat exchange medium on the methanol side is increased, thereby improving the stability of the reaction system.

Claims

1. An online cleaning system for a methanol-reaction gas heat exchanger, characterized in that: The invention comprises two reaction gas heat exchangers (1), the tops of the two reaction gas heat exchangers (1) are connected to an air intake unit, an online cleaning mechanism is connected between the two air intake units, the bottoms of the two reaction gas heat exchangers (1) are respectively connected to a first exhaust pipe (2) and a second exhaust pipe (3), and the ends of the first exhaust pipe (2) and the second exhaust pipe (3) away from the reaction gas heat exchanger (1) are connected to an exhaust main pipe (4).

2. The online cleaning system for the methanol-reaction gas heat exchanger according to claim 1, characterized in that: The pipe bodies of the first exhaust pipe (2) and the second exhaust pipe (3) are both connected to exhaust valves (5).

3. The online cleaning system for the methanol-reaction gas heat exchanger according to claim 1, characterized in that: The air intake unit comprises a first air intake pipe (6) and a second air intake pipe (7), the first air intake pipe (6) and the second air intake pipe (7) are respectively connected to the tops of two reaction gas heat exchangers (1), the ends of the first air intake pipe (6) and the second air intake pipe (7) away from the reaction gas heat exchangers (1) are connected to an air intake main pipe (8), and the online cleaning mechanism is connected between the first air intake pipe (6) and the second air intake pipe (7).

4. The online cleaning system for the methanol-reaction gas heat exchanger according to claim 3, characterized in that: The pipe bodies of the first air intake pipe (6) and the second air intake pipe (7) are both connected to air intake valves (9), and the connection points between the online cleaning mechanism and the first air intake pipe (6) and the second air intake pipe (7) are respectively arranged below the two air intake valves (9).

5. The online cleaning system for the methanol-reaction gas heat exchanger according to claim 4, characterized in that: The online cleaning mechanism comprises a first storage tank (10) and a second storage tank (11), the first storage tank (10) and the second storage tank (11) being connected to a nitrogen system, the bottoms of the first storage tank (10) and the second storage tank (11) being connected to a first outlet pipe (12) and a second outlet pipe (13) respectively, the end of the first outlet pipe (12) away from the first storage tank (10) being connected to a first air inlet pipe (6), the end of the second outlet pipe (13) away from the second storage tank (11) being connected to a second air inlet pipe (7), the connection point between the first outlet pipe (12) and the first air inlet pipe (6) and the connection point between the second outlet pipe (13) and the second air inlet pipe (7) being respectively arranged below two air inlet valves (9).

6. The online cleaning system for the methanol-reaction gas heat exchanger according to claim 5, characterized in that: The pipe body of the first outlet pipe (12) is connected to a first outlet valve (14) and a second outlet valve (15), the first outlet valve (14) being arranged close to the first storage tank (10), the second outlet valve (15) being arranged close to a connection point between the first outlet pipe (12) and the first air inlet pipe (6), the pipe body of the second outlet pipe (13) being connected to a third outlet valve (16) and a fourth outlet valve (17), the third outlet valve (16) being arranged close to the second storage tank (11), the fourth outlet valve (17) being arranged close to a connection point between the second outlet pipe (13) and the second air inlet pipe (7).

7. The online cleaning system for the methanol-reaction gas heat exchanger according to claim 5, characterized in that: The nitrogen system comprises a nitrogen main pipe (18), one end of the nitrogen main pipe (18) is connected to a branch pipe (19), both ends of the branch pipe (19) are respectively connected to a first outlet pipe (12) and a second outlet pipe (13), the connection points of the branch pipe (19) with the first outlet pipe (12) and the second outlet pipe (13) are respectively arranged between a first outlet valve (14) and a second outlet valve (15), a third outlet valve (16) and a fourth outlet valve (17), the pipe body of the branch pipe (19) is connected to a first nitrogen pipe (20) and a second nitrogen pipe (24), and the ends of the first nitrogen pipe (20) and the second nitrogen pipe (24) away from the branch pipe (19) are respectively connected to the side walls of the first storage tank (10) and the second storage tank (11).

8. The online cleaning system for the methanol-reaction gas heat exchanger according to claim 7, characterized in that: The first nitrogen pipe (20) and the second nitrogen pipe (24) are arranged on both sides of the connection point between the branch pipe (19) and the nitrogen main pipe (18); the pipe bodies of the first nitrogen pipe (20) and the second nitrogen pipe (24) are both connected with nitrogen inlet valves (21); the two nitrogen inlet valves (21) are respectively arranged close to the first storage tank (10) and the second storage tank (11); the pipe body of the branch pipe (19) is connected with a first control valve (22) and a second control valve (23); the first control valve (22) is arranged between the connection point between the branch pipe (19) and the first outlet pipe (12) and the connection point between the branch pipe (19) and the first nitrogen pipe (20); the second control valve (23) is arranged between the connection point between the branch pipe (19) and the second outlet pipe (13) and between the branch pipe (19) and the second nitrogen pipe (24); the pipe body of the nitrogen main pipe (18) is connected with a nitrogen main valve (25).

9. The online cleaning system for the methanol-reaction gas heat exchanger according to claim 7, characterized in that: The tops of the first storage tank (10) and the second storage tank (11) are both connected to a feed pipe (26), and the bodies of the two feed pipes (26) are both connected to a feed valve (27).

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