Steam supply system for ethylene glycol production

Abstract

The utility model belongs to the technical field of steam recovery, and relates to a steam supply system for ethylene glycol production, which comprises a steam flash tank, a steam condenser and a second steam pipe network, the steam flash tank is externally connected with a steam condensate inlet pipe, a byproduct steam pipe and a byproduct steam conveying pipe respectively; the steam condensate inlet pipe is respectively communicated with a byproduct steam pipe and a byproduct steam conveying pipe after passing through the steam flash tank; the byproduct steam conveying pipe is communicated with the steam condenser; and the byproduct steam pipe is communicated with the second steam pipe network. According to the utility model, by-product steam generated by the steam flash tank is introduced into the steam condenser to be cooled and recycled, so that steam waste is greatly reduced, and resources are saved; steam balance in the second steam pipe network is ensured, and the ethylene glycol product quality is stable.

Description

Technical Field

[0001] The utility model belongs to the technical field of steam recovery and relates to a steam supply system for ethylene glycol production. Background Art

[0002] In ethylene glycol production, a 0.2 MPa steam network is used to supply steam to the ethylene glycol production system. At the same time, since by-product 0.2 MPa steam is also generated in the ethylene glycol production system, specifically, the by-product 0.2 MPa steam generated by three devices, namely the condenser at the top of the light component removal tower in ethylene glycol rectification, the condenser at the top of the ethylene glycol product tower, and the steam flash tank, is incorporated into the 0.2 MPa steam network. However, during the incorporation process, there will be a situation of insufficient pressure. Therefore, the steam in the 0.5 MPa steam network is reduced in pressure to 0.2 MPa steam and then also sent into the 0.2 MPa steam network, thereby supplementing the pressure of the 0.2 MPa steam network through pressure reduction. Although the existing steam system can ensure the operation of ethylene glycol production, there are the following problems:

[0003] (1) When the pressure of the 0.5 MPa steam network outside the ethylene glycol production boundary is too high, it is necessary to consume the surplus 0.5 MPa saturated steam in the network by connecting the 0.5 MPa saturated steam in the ethylene glycol purification area in series with the 0.2 MPa steam network, thereby generating excessive 0.2 MPa steam; however, during the ethylene glycol production process, the excessive 0.2 MPa steam cannot be consumed and can only be solved by on-site venting. In this way, a large amount of steam condensate is lost, and the loss reaches about 20 t / h, resulting in waste of resources;

[0004] (2) The excessive by-product 0.2 MPa steam will cause a large pressure in the network, resulting in a decrease in the vacuum degrees of the light component removal tower and the ethylene glycol product tower in ethylene glycol rectification, and further leading to unstable steam in the ethylene glycol system and fluctuations in the quality of the ethylene glycol product, and even unqualified situations may occur. Summary of the Utility Model

[0005] In view of the technical problems of resource waste existing in the existing by-product steam and fluctuations in the quality of ethylene glycol products, the utility model provides a steam supply system for ethylene glycol production.

[0006] In the utility model, by setting a steam flash tank, a steam condenser, and a second steam network, the by-product steam generated by the steam flash tank is introduced into the steam condenser for cooling and recycling, greatly reducing steam waste and saving resources; ensuring the steam balance in the second steam network and ensuring the stable quality of ethylene glycol products.

[0007] In order to achieve the above object, the technical solution adopted by the utility model is:

[0008] A steam supply system for ethylene glycol production includes a steam flash tank, a steam condenser, and a second steam network;

[0009] The steam flash tank is respectively connected with a steam condensate inlet pipe, a by-product steam pipe and a by-product steam conveying pipe; the steam condensate inlet pipe is respectively connected with the by-product steam pipe and the by-product steam conveying pipe after passing through the steam flash tank; the by-product steam conveying pipe is connected with a steam condenser; and the by-product steam pipe is connected with a second steam pipe network.

[0010] It is further defined that a first control valve and a second control valve are respectively arranged on the by-product steam conveying pipe in sequence along the steam conveying direction.

[0011] It is further defined that the ethylene glycol production steam supply system also includes a by-product steam vent pipe connected to the by-product steam delivery pipe; the by-product steam vent pipe is located between the first control valve and the second control valve.

[0012] It is further defined that a third control valve is provided on the by-product steam vent pipe.

[0013] It is further defined that the steam condenser is respectively externally connected with a steam condenser inlet pipe and a steam condenser outlet pipe; the by-product steam conveying pipe is connected with the steam condenser outlet pipe via the steam condenser inlet pipe and the steam condenser.

[0014] It is further defined that the steam condenser is also externally connected with a circulating water inlet pipe and a circulating water outlet pipe respectively; the circulating water inlet pipe is connected with the circulating water outlet pipe through the steam condenser.

[0015] It is further defined that control valves are respectively provided on the circulating water inlet pipe and the circulating water outlet pipe.

[0016] It is further defined that the ethylene glycol production steam supply system also includes a steam condensate buffer tank connected to the steam condenser outlet pipe.

[0017] It is further defined that the ethylene glycol production steam supply system also includes a first steam pipeline network, an ethylene glycol lightness removal tower condenser and an ethylene glycol product tower condenser respectively connected to the second steam pipeline network.

[0018] The beneficial effects of the technical solution of the utility model are:

[0019] 1. In the utility model, the by-product steam generated by the steam flash tank is introduced into the steam condenser for cooling and recycling, the pressure of the second steam pipe network is adjusted, the balance of the steam is stabilized, the abnormal production caused by steam fluctuations is prevented, the operating stability of the ethylene glycol device is improved; and the steam waste is greatly reduced, saving resources.

[0020] 2. In the utility model, by providing the first control valve and the second control valve, it is not only beneficial to guide the by-product steam to the steam condenser for condensation, but also can control the flow of the by-product steam to ensure the stable balance of the system steam.

[0021] 3. In the present utility model, the by-product steam enters the steam condenser for recovery instead of being vented, greatly improving the problem of excessive noise caused by on-site venting.

[0022] 4. The recovery system of the present utility model has a simple structure, is convenient to operate, saves costs, and can generate significant economic benefits after implementation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the low-pressure by-product steam recovery and utilization system provided by the present utility model;

[0024] Wherein:

[0025] 10 - steam flash tank; 101 - steam condensate inlet pipe; 102 - by-product steam pipe; 103 - by-product steam vent pipe; 104 - by-product steam transfer pipe; 20 - steam condenser; 201 - steam condenser inlet pipe; 202 - steam condenser outlet pipe; 203 - circulating water inlet pipe; 204 - circulating water outlet pipe; 30 - steam condensate buffer tank; 40 - first steam pipe network; 50 - second steam pipe network; 60 - ethylene glycol de-lighting tower condenser; 70 - ethylene glycol product tower condenser. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] In order to make the purpose, technical solutions and advantages of the present utility model more clear and understandable, the present utility model will be further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present utility model and do not limit the protection scope of the present utility model.

[0027] Embodiment

[0028] Refer to Figure 1 , a steam supply system for ethylene glycol production provided in this embodiment includes a steam flash tank 10, a steam condenser 20 and a second steam pipe network 50.

[0029] The steam supply system for ethylene glycol production provided in this embodiment further includes a first steam pipe network 40, an ethylene glycol de-lighting tower condenser 60 and an ethylene glycol product tower condenser 70 which are respectively communicated with the second steam pipe network 50.

[0030] Preferably, the first steam pipe network 40 is a 0.5 MPa steam pipe network; the second steam pipe network 50 is a 0.2 MPa steam pipe network, that is, the ethylene glycol by-product steam pipe network.

[0031] Preferably, the second steam pipe network 50 is respectively connected to the first steam pipe network 40, the top of the ethylene glycol de-lighting tower condenser 60, and the top of the ethylene glycol product tower condenser 70, so that the 0.5 MPa steam in the first steam pipe network 40 is depressurized and enters the second steam pipe network 50. At the same time, the by-product steam generated at the top of the ethylene glycol de-lighting tower condenser 60 (0.2 MPa by-product steam) and the by-product steam generated at the top of the ethylene glycol product tower condenser 70 (0.2 MPa by-product steam) also enter the second steam pipe network 50 to provide an appropriate pressure to the system and ensure the normal operation of the ethylene glycol system.

[0032] In this embodiment, a steam condensate inlet pipe 101, a by-product steam pipe 102, and a by-product steam delivery pipe 104 are respectively externally connected to the steam flash tank 10; the steam condensate inlet pipe 101 is respectively connected to the by-product steam pipe 102 and the by-product steam delivery pipe 104 after passing through the steam flash tank 10; the by-product steam delivery pipe 104 is connected to the steam condenser 20; the by-product steam pipe 102 is connected to the second steam pipe network 50.

[0033] During implementation, the 0.5 MPa steam condensate is introduced into the steam condensate inlet pipe 101. The purpose of the steam flash tank 10 is to flash the 0.5 MPa steam condensate introduced from the steam condensate inlet pipe 101 to obtain 0.2 MPa by-product steam; then the 0.2 MPa by-product steam is divided into two paths. One path enters the second steam pipe network 50 through the by-product steam pipe 102 for providing reaction steam for ethylene glycol production; the other path enters the steam condenser 20 through the by-product steam delivery pipe 104 and is recovered after cooling; it can ensure the stability of the steam in the second steam pipe network 50 (0.2 MPa steam pipe network), effectively avoid steam fluctuations, and ensure the stability of ethylene glycol quality.

[0034] In this embodiment, a first control valve and a second control valve are sequentially arranged along the steam delivery direction on the by-product steam delivery pipe 104. The flow rate of the steam entering the steam condenser 20 is controlled by the first control valve and the second control valve. Exemplarily, when there is too much steam and the pressure increases in the second steam pipe network 50 (0.2 MPa steam pipe network), the first control valve and the second control valve are opened to discharge the 0.2 MPa by-product steam in the steam flash tank 10 into the steam condenser 20, while recovering the by-product steam, ensuring the steam balance and stability of the second steam pipe network 50.

[0035] In this embodiment, the ethylene glycol production steam supply system further includes a by-product steam vent pipe 103 connected to the by-product steam delivery pipe 104; the by-product steam vent pipe 103 is located between the first control valve and the second control valve.

[0036] During implementation, the by-product steam delivery pipe 104 is also connected to the by-product steam vent pipe 103 as a backup. In the event of a failure in the steam supply system for ethylene glycol production, the 0.2 MPa by-product steam in the steam flash tank 10 is directly vented.

[0037] Preferably, a third control valve is provided on the by-product steam vent pipe 103 to control the opening and closing of the by-product steam vent pipe 103. When the steam supply system for ethylene glycol production is operating normally, the third control valve is closed, and the first and second control valves are open; when the steam supply system for ethylene glycol production is not operating properly, or when the pressure in the second steam pipe network 50 (0.2 MPa steam pipe network) is still too high even when the first and second control valves are open, the third control valve can be opened for venting.

[0038] In this embodiment, a steam condenser inlet pipe 201 and a steam condenser outlet pipe 202 are respectively externally connected to the steam condenser 20; the by-product steam delivery pipe 104 is connected to the steam condenser outlet pipe 202 through the steam condenser inlet pipe 201 and the steam condenser 20. A circulating water inlet pipe 203 and a circulating water outlet pipe 204 are also respectively externally connected to the steam condenser 20; the circulating water inlet pipe 203 is connected to the circulating water outlet pipe 204 through the steam condenser 20.

[0039] During implementation, the steam condenser 20 is of the shell-and-tube type or the tube-and-shell type, and the by-product steam and the circulating water flow in different tubes and shells. Preferably, the by-product steam flows from left to right in the tube side, and the circulating water flows from bottom to top in the shell side. The circulating water is used to cool the by-product steam (i.e., 0.2 MPa by-product steam), and the condensate obtained is discharged from the steam condenser outlet pipe 202, and the cooled steam condensate is pressed into the steam condensate buffer tank 30 by the residual pressure and sent to the steam condensate pipe network for recycling and reuse.

[0040] Preferably, control valves are respectively provided on the circulating water inlet pipe 203 and the circulating water outlet pipe 204; the flow rate of the circulating water is controlled through the control valves to improve the cooling efficiency.

[0041] The steam supply system for ethylene glycol production provided by the present utility model adds a steam condenser 20 after the steam flash tank 10, leads the by-product steam (pressure: 0.2 MPa) on the steam flash tank 10 to the steam condenser 20 for cooling and recovery, realizes the reuse of the by-product steam, saves resources, balances the pressures in the first steam pipe network 40 and the second steam pipe network 50, reduces the pressure in the second steam pipe network 50 (0.2 MPa steam pipe network), thereby reducing steam waste, achieving steam balance, improving the operation stability of ethylene glycol, preventing abnormal production situations caused by steam fluctuations, and improving the quality of ethylene glycol products; at the same time, instead of discharging the by-product steam, it is recovered, which can also improve the problem of excessive on-site discharge noise; in addition, calculated according to the by-product steam condensate discharge volume of 20 t / h and the unit price of 0.2 MPa steam condensate of about 12 yuan / t, the cost saved is 20 t / h × 0.0012 ten thousand yuan / t = 0.024 ten thousand yuan / h. Calculated based on the annual production operation time of 7200 h, 1.728 million yuan can be saved per year. It can be seen that adopting the recovery system of the present utility model can bring significant economic benefits.

[0042] Although the embodiments of the present utility model have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present utility model, and all of them will fall within the protection scope of the present utility model.

Claims

1. A steam supply system for ethylene glycol production, characterized in that: It comprises a steam flash tank (10), a steam condenser (20) and a second steam pipe network (50); The steam flash tank (10) is externally connected to a steam condensate inlet pipe (101), a byproduct steam pipe (102) and a byproduct steam delivery pipe (104); the steam condensate inlet pipe (101) is connected to the byproduct steam pipe (102) and the byproduct steam delivery pipe (104) respectively after passing through the steam flash tank (10); the byproduct steam delivery pipe (104) is connected to a steam condenser (20); and the byproduct steam pipe (102) is connected to a second steam pipe network (50).

2. The ethylene glycol production steam supply system according to claim 1, characterized in that: The by-product steam conveying pipe (104) is provided with a first control valve and a second control valve in sequence along the steam conveying direction.

3. The ethylene glycol production steam supply system according to claim 2, characterized in that: The ethylene glycol production steam supply system further comprises a byproduct steam vent pipe (103) connected to the byproduct steam delivery pipe (104); the byproduct steam vent pipe (103) is located between the first control valve and the second control valve.

4. The ethylene glycol production steam supply system according to claim 3, characterized in that: A third control valve is provided on the by-product steam vent pipe (103).

5. The ethylene glycol production steam supply system according to claim 4, characterized in that: The steam condenser (20) is respectively connected to a steam condenser inlet pipe (201) and a steam condenser outlet pipe (202); the by-product steam delivery pipe (104) is connected to the steam condenser outlet pipe (202) via the steam condenser inlet pipe (201) and the steam condenser (20).

6. The ethylene glycol production steam supply system according to claim 5, characterized in that: The steam condenser (20) is also externally connected to a circulating water inlet pipe (203) and a circulating water outlet pipe (204); the circulating water inlet pipe (203) is connected to the circulating water outlet pipe (204) via the steam condenser (20).

7. The ethylene glycol production steam supply system according to claim 6, characterized in that: Control valves are respectively arranged on the circulating water inlet pipe (203) and the circulating water outlet pipe (204).

8. The ethylene glycol production steam supply system according to claim 5, 6 or 7, characterized in that: The ethylene glycol production steam supply system further comprises a steam condensate buffer tank (30) connected to the steam condenser outlet pipe (202).

9. The ethylene glycol production steam supply system according to claim 1, characterized in that: The ethylene glycol production steam supply system further comprises a first steam pipe network (40), an ethylene glycol lightness removal tower condenser (60) and an ethylene glycol product tower condenser (70) respectively connected to a second steam pipe network (50).

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