Waste heat recovery energy-saving equipment of hydrolysis ethylene glycol preparation device

Abstract

The utility model discloses waste heat recovery energy-saving equipment of a device for preparing ethylene glycol through hydrolysis, which belongs to the technical field of chemical production and comprises a circulating liquid cooler and an ethylene glycol refining tower top cooler, and an ethylene glycol refining tower is arranged on one side of the ethylene glycol refining tower top cooler. A discharge port of the reactor is connected with a feed port of the reaction circulating liquid pump through a pipeline, a flow meter d, a flow control valve d and a waste heat recovery supercharger are arranged on the bypass pipeline, the bypass pipeline is connected with the waste heat recovery supercharger, and a flow meter e and a flow control valve e are arranged on the bypass pipeline. After being pressurized, process steam generated by the circulating liquid cooler and the ethylene glycol refining tower top cooler meets the requirement of 0.6 Mpa grade steam which can be used by a hydrolysis ethylene glycol preparation device, so that the problem of waste is avoided, meanwhile, the circulating water consumption of the device can be reduced, the steam unit consumption and the circulating water unit consumption in the operation of the device are reduced, and the energy consumption of the device is reduced. And economic income is increased for the device, so that the device is in efficient and energy-saving operation for a long time.

Description

Technical Field

[0001] This utility model relates to the field of chemical production technology, specifically to an energy-saving device for waste heat recovery in a hydrolysis-to-ethylene glycol production unit. Background Technology

[0002] In the hydrolysis to ethylene glycol plant, the circulating liquid heat exchanger, the condenser at the top of the ethylene glycol refining tower, and other equipment generate process steam with a pressure of <0.1 MPa after heat exchange and cooling. This low-quality steam leads to venting, waste, and increased steam energy consumption of the plant. Although existing technologies can recover this low-grade steam, it is difficult to achieve the required 0.6 MPa steam pressure for use in the hydrolysis to ethylene glycol plant. Therefore, existing technologies cannot effectively guarantee the efficient and energy-saving operation of the hydrolysis to ethylene glycol plant. Utility Model Content

[0003] To address the technical problems mentioned in the background section, this utility model provides an energy-saving device for waste heat recovery in a hydrolysis-to-ethylene glycol production unit, employing the following technical solution:

[0004] The system includes a circulating liquid cooler and an ethylene glycol refining tower overhead cooler. An ethylene glycol refining tower is located on one side of the overhead cooler, and its exhaust port is connected to the steam inlet of the overhead cooler via a pipeline. A circulating liquid preheater is located on one side of the circulating liquid cooler, and its outlet is connected to the inlet of the preheater via a pipeline. A reactor is located on one side of the preheater, and its outlet is connected to the inlet of the reactor via a pipeline. A reaction circulating liquid pump is located on one side of the reactor, and its outlet is connected to the inlet of the reactor via a pipeline. A reaction circulating liquid pump is located on one side of the reactor, and its outlet is connected to the reactor's circulating liquid pump. The inlet of the circulating liquid pump is connected to the outlet of the reaction circulating liquid pump and the inlet of the circulating liquid cooler via a pipeline, and a bypass pipeline is installed on the pipeline. The bypass pipeline is equipped with a flow meter d, a flow control valve d, and a waste heat recovery booster. The waste heat recovery booster is equipped with a steam pipeline, and a gate valve a and a pressure gauge are installed on the steam pipeline. A bypass pipeline is installed on the pipeline connecting the ethylene glycol refining tower and the ethylene glycol refining tower top cooler. The bypass pipeline is connected to the waste heat recovery booster, and a flow meter e and a flow control valve e are installed on the bypass pipeline.

[0005] Furthermore, an ethylene oxide bypass pipeline is installed on the pipeline between the circulating liquid preheater and the reactor, and a flow meter a and a flow control valve a are installed on the ethylene oxide bypass pipeline. A carbon dioxide bypass pipeline is also installed on the pipeline between the circulating liquid preheater and the reactor, and a flow meter b and a flow control valve b are installed on the carbon dioxide bypass pipeline.

[0006] Furthermore, a bypass pipeline is installed on the pipeline between the reactor and the reaction circulating liquid pump, and a flow meter c and a flow control valve c are installed on the bypass pipeline.

[0007] Furthermore, a bypass pipeline is installed on the pipeline between the reactor and the circulating liquid preheater, and the bypass pipeline is connected to the waste heat recovery booster. A gate valve d is installed on the bypass pipeline.

[0008] Furthermore, a pipeline is installed on one side of the waste heat recovery booster, and a gate valve f is installed on the pipeline.

[0009] Furthermore, an ethylene glycol refining tower reflux tank is installed on one side of the top cooler of the ethylene glycol refining tower. The outlet of the top cooler of the ethylene glycol refining tower is connected to the inlet of the ethylene glycol refining tower reflux tank via a pipeline. An ethylene glycol refining tower reflux pump is installed on one side of the ethylene glycol refining tower reflux tank. The outlet of the ethylene glycol refining tower reflux tank is connected to the inlet of the ethylene glycol refining tower reflux pump via a pipeline. The outlet of the ethylene glycol refining tower reflux pump is connected to the ethylene glycol refining tower via a pipeline, and a gate valve b is installed on the pipeline.

[0010] Furthermore, a bypass pipeline is installed on the pipeline between the ethylene glycol refining tower reflux pump and the ethylene glycol refining tower, and a flow meter f and a flow control valve f are installed on the bypass pipeline.

[0011] Furthermore, a pipeline is installed at the bottom of the ethylene glycol refining tower, and a gate valve c is installed on the pipeline.

[0012] Furthermore, a bypass pipeline is installed on the pipeline between the reflux tank of the ethylene glycol refining tower and the top cooler of the ethylene glycol refining tower, and the bypass pipeline is connected to the waste heat recovery booster. A gate valve e is installed on the bypass pipeline.

[0013] This invention has the following advantages: By recovering the low-quality steam (<0.1 MPa) generated by the circulating liquid cooler and the ethylene glycol refining tower, and then pressurizing it to meet the 0.6 MPa level required for the hydrolysis to ethylene glycol production unit, this invention utilizes the low-quality steam, avoids waste, and reduces the circulating water consumption of the unit, thereby reducing the steam and circulating water consumption during operation, increasing economic revenue for the unit, and ensuring that the unit operates at high efficiency and energy saving for a long time. Attached Figure Description

[0014] Figure 1 This is a process drawing of the present utility model.

[0015] Attached Figures: 1-Flow meter a, 2-Flow control valve a, 3-Flow meter b, 4-Flow control valve b, 5-Circulating liquid preheater, 6-Circulating liquid cooler, 7-Reaction circulating liquid pump, 8-Flow meter c, 9-Flow control valve c, 10-Reactor, 11-Flow meter d, 12-Flow control valve d, 13-Waste heat recovery booster, 14-Gate valve a, 15-Pressure gauge, 16-Ethylene glycol refining tower, 17-Gate valve b, 18-Flow meter e, 19-Flow control valve e, 20-Gate valve c, 21-Flow control valve f, 22-Flow meter f, 23-Ethylene glycol refining tower reflux pump, 24-Ethylene glycol refining tower reflux tank, 25-Ethylene glycol refining tower top cooler, 26-Gate valve d, 27-Gate valve e, 28-Gate valve f. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0017] Please refer to Figure 1This utility model discloses a waste heat recovery and energy-saving device for a hydrolysis-to-ethylene glycol production unit, including a circulating liquid cooler 6 and an ethylene glycol refining tower top cooler 25. An ethylene glycol refining tower 16 is located on one side of the ethylene glycol refining tower top cooler 25. When the circulating liquid cooler 6 cools the material, it generates process steam at a pressure of <0.1 MPa. The steam generated in the ethylene glycol refining tower 16 enters the ethylene glycol refining tower top cooler 25 and generates process steam at a pressure of <0.1 MPa during cooling. The exhaust port of the ethylene glycol refining tower 16 is connected to the inlet of the ethylene glycol refining tower top cooler 25 via a pipeline. A circulating liquid preheater 5 is installed on one side of the circulating liquid cooler 6. The outlet of the circulating liquid cooler 6 is connected to the inlet of the circulating liquid preheater 5 via a pipeline. A reactor 10 is installed on one side of the circulating liquid preheater 5. The outlet of the circulating liquid preheater 5 is connected to the inlet of the reactor 10 via a pipeline. A reaction circulating liquid pump 7 is installed on one side of the reactor 10. The outlet of the reactor 10 is connected to the inlet of the reaction circulating liquid pump 7 via a pipeline. Ethylene oxide and carbon dioxide enter the reactor 10 and react to produce ethylene carbonate, which is then pumped into the circulating liquid cooler 6 for cooling via the reaction circulating liquid pump 7. The fluid enters the circulating liquid preheater 5 for preheating before returning to the reactor 10. The outlet of the circulating liquid pump 7 is connected to the inlet of the circulating liquid cooler 6 via a pipeline with a bypass pipeline. This bypass pipeline is equipped with a flow meter d11, a flow control valve d12, and a waste heat recovery booster 13. The flow rate in this bypass pipeline is controlled by the flow meter d11 and the flow control valve d12. The process steam generated by the circulating liquid cooler 6 enters the waste heat recovery booster 13 through this bypass pipeline for pressurization. The waste heat recovery booster 13 is equipped with a steam pipeline, and the steam pipeline is equipped with… Gate valve a14 and pressure gauge 15 are provided. Gate valve a14 controls the opening and closing of the pipeline, and pressure gauge 15 monitors the pressure in the steam pipeline. A bypass pipeline is provided on the pipeline connecting ethylene glycol refining tower 16 and ethylene glycol refining tower top cooler 25. The bypass pipeline is connected to waste heat recovery booster 13 and is equipped with flow meter e18 and flow control valve e19. The process steam generated by ethylene glycol refining tower top cooler 25 enters waste heat recovery booster 13 through the bypass pipeline for pressurization. Flow meter e18 and flow control valve e19 control the flow rate in the bypass pipeline.

[0018] An ethylene oxide bypass pipeline is installed on the pipeline between the circulating liquid preheater 5 and the reactor 10. Flow meter a1 and flow control valve a2 are installed on the ethylene oxide bypass pipeline. Flow meter a1 and flow control valve a2 control the flow rate in the bypass pipeline. Ethylene oxide enters the reactor 10 through this bypass pipeline. A carbon dioxide bypass pipeline is also installed on the pipeline between the circulating liquid preheater 5 and the reactor 10. Flow meter b3 and flow control valve b4 are installed on the carbon dioxide bypass pipeline. Flow meter b3 and flow control valve b4 control the flow rate in the bypass pipeline. Carbon dioxide enters the reactor 10 through this bypass pipeline. A bypass pipeline is installed on the pipeline between the reactor 10 and the reaction circulating liquid pump 7. Flow meter c8 and flow control valve c9 are installed on the bypass pipeline. Flow meter c8 and flow control valve c9 control the flow rate in the bypass pipeline. Part of the ethylene carbonate produced in the reactor 10 is discharged to the downstream process through this bypass pipeline.

[0019] A bypass pipeline is installed between reactor 10 and circulating liquid preheater 5, and the bypass pipeline is connected to waste heat recovery booster 13. A gate valve d26 is installed on the bypass pipeline, and the gate valve d26 controls the opening and closing of the bypass pipeline. When ethylene carbonate is refluxed into reactor 10, the residual process steam enters the waste heat recovery booster 13 through the bypass pipeline for pressurization. A pipeline is installed on one side of the waste heat recovery booster 13, and a gate valve f28 is installed on the pipeline, and the gate valve f28 controls the opening and closing of the pipeline.

[0020] An ethylene glycol refining tower reflux tank 24 is installed on one side of the overhead cooler 25. The outlet of the overhead cooler 25 is connected to the inlet of the ethylene glycol refining tower reflux tank 24 via a pipeline. An ethylene glycol refining tower reflux pump 23 is installed on one side of the ethylene glycol refining tower reflux tank 24. The outlet of the ethylene glycol refining tower reflux tank 24 is connected to the inlet of the ethylene glycol refining tower reflux pump 23 via a pipeline. The discharge port is connected to the ethylene glycol refining tower 16 via a pipeline, and a gate valve b17 is installed on the pipeline. The gate valve b17 controls the opening and closing of the pipeline. Through the pipeline, the condensate generated in the top cooler 25 of the ethylene glycol refining tower enters the ethylene glycol refining tower reflux tank 24 and is collected. The condensate in the ethylene glycol refining tower reflux tank 24 is sent into the ethylene glycol refining tower 16 by the ethylene glycol refining tower reflux pump 23 to fully refine the condensate.

[0021] A bypass line is installed on the pipeline between the ethylene glycol refining tower reflux pump 23 and the ethylene glycol refining tower 16. A flow meter f22 and a flow control valve f21 are installed on the bypass line. Flow meter f22 and flow control valve f21 control the flow rate of the bypass line. A portion of the qualified ethylene glycol (EG) exits through this bypass line. A pipeline with a gate valve c20 is installed at the bottom of the ethylene glycol refining tower 16. Gate valve c20 controls the opening and closing of this pipeline. Ethylene glycol produced in the ethylene glycol refining tower 16 is discharged through this pipeline. Ethylene glycol refining... A bypass pipeline is installed on the pipeline between the reflux tank 24 and the overhead cooler 25 of the ethylene glycol refining tower, and the bypass pipeline is connected to the waste heat recovery booster 13. A gate valve e27 is installed on the bypass pipeline, which controls the opening and closing of the bypass pipeline. When the condensate in the overhead cooler 25 of the ethylene glycol refining tower enters the reflux tank 24, some residual process steam with a pressure of <0.1 MPa enters the waste heat recovery booster 13 through the bypass pipeline for pressurization, so that the process steam with a pressure of <0.1 MPa is recovered more fully.

[0022] The working principle of this utility model is as follows: raw materials ethylene oxide and carbon dioxide enter the reactor 10 through the ethylene oxide bypass pipeline and the carbon dioxide bypass pipeline respectively under the conditions of 4.1 MPa and 120℃. After reaction, ethylene carbonate is generated. Part of it enters the circulating liquid cooler 6 through the reaction liquid circulation pump 7 for cooling. The circulating liquid cooler 6 generates process steam with a pressure of <0.1 MPa. This part of the steam enters the waste heat recovery booster 13 for pressurization.

[0023] The ethylene glycol refining tower 16 refines the 98% ethylene glycol aqueous solution from the dehydration tower at a controlled temperature of 8 kPa and 130°C. The vapor phase enters the ethylene glycol refining tower top cooler 25 from the top of the tower for cooling. Process steam with a pressure of <0.1 MPa is generated in the ethylene glycol refining tower top cooler 25. This steam enters the waste heat recovery booster 13 for pressurization. In this way, the <0.1 MPa process steam generated by the circulating liquid cooler 6 and the ethylene glycol refining tower top cooler 25 is pressurized by the preheating recovery booster 13 to a steam cake with a pressure of 0.6 MPa that meets the requirements of the hydrolysis to ethylene glycol unit, and then sent into the steam pipeline network.

[0024] By opening the flow meters d11, flow control valve d12, flow meter e18, and flow control valve e19 installed on each pipeline, the load entering the waste heat recovery booster 13 can be precisely adjusted. Of course, the flow rate should not be too fast, otherwise it will cause fluctuations in the liquid level of the waste heat recovery system. When the liquid level of the waste heat recovery booster 13 is insufficient, we can open the gate valve f28 to replenish condensate and maintain the liquid level. As the load of the waste heat recovery booster 13 increases, the pressure gauge 15 will continue to rise. We first pressurize it to 0.62 MPa before opening the gate valve a14 to connect to the steam network. In this way, we can recover low-quality steam, achieve high-efficiency steam, and enable the hydrolysis to ethylene glycol production unit to operate in an energy-saving manner.

[0025] This invention is simple to operate, convenient to use, and suitable for widespread promotion and application. Although embodiments of this invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and alterations can be made to these embodiments without departing from the principles and spirit of this invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A waste heat recovery and energy-saving device for a hydrolysis-to-ethylene glycol plant, comprising a circulating liquid cooler (6) and an ethylene glycol refining tower top cooler (25), wherein an ethylene glycol refining tower (16) is provided on one side of the ethylene glycol refining tower top cooler (25), and the exhaust port of the ethylene glycol refining tower (16) is connected to the steam inlet of the ethylene glycol refining tower top cooler (25) via a pipeline, characterized in that, A circulating liquid preheater (5) is provided on one side of the circulating liquid cooler (6). The outlet of the circulating liquid cooler (6) is connected to the inlet of the circulating liquid preheater (5) through a pipeline. A reactor (10) is provided on one side of the circulating liquid preheater (5). The outlet of the circulating liquid preheater (5) is connected to the inlet of the reactor (10) through a pipeline. A reaction circulating liquid pump (7) is provided on one side of the reactor (10). The outlet of the reactor (10) is connected to the inlet of the reaction circulating liquid pump (7) through a pipeline. The outlet of the reaction circulating liquid pump (7) is connected to the inlet of the circulating liquid cooler (6) through a pipeline, and a bypass pipeline is provided on the pipeline. A flow meter d (11), a flow control valve d (12), and a waste heat recovery booster (13) are provided on the bypass pipeline. A steam pipeline is provided on the waste heat recovery booster (13), and a gate valve a (14) and a pressure gauge (15) are provided on the steam pipeline. A bypass line is provided on the pipeline connecting the ethylene glycol refining tower (16) and the ethylene glycol refining tower top cooler (25). The bypass line is connected to the waste heat recovery booster (13) and is equipped with a flow meter e (18) and a flow control valve e (19).

2. The waste heat recovery and energy-saving equipment for a hydrolysis-to-ethylene glycol production unit according to claim 1, characterized in that, An ethylene oxide bypass pipeline is installed on the pipeline between the circulating liquid preheater (5) and the reactor (10), and a flow meter a (1) and a flow control valve a (2) are installed on the ethylene oxide bypass pipeline. A carbon dioxide bypass pipeline is also installed on the pipeline between the circulating liquid preheater (5) and the reactor (10), and a flow meter b (3) and a flow control valve b (4) are installed on the carbon dioxide bypass pipeline.

3. The waste heat recovery and energy-saving equipment for a hydrolysis-to-ethylene glycol production unit according to claim 1, characterized in that, A bypass pipeline is installed on the pipeline between the reactor (10) and the reaction circulating liquid pump (7), and a flow meter c (8) and a flow control valve c (9) are installed on the bypass pipeline.

4. The waste heat recovery and energy-saving equipment for a hydrolysis-to-ethylene glycol production unit according to claim 1, characterized in that, A bypass pipeline is provided between the reactor (10) and the circulating liquid preheater (5) and the bypass pipeline is connected to the waste heat recovery booster (13). A gate valve d (26) is provided on the bypass pipeline.

5. The waste heat recovery and energy-saving equipment for a hydrolysis-to-ethylene glycol production unit according to claim 1, characterized in that, A pipeline is installed on one side of the waste heat recovery booster (13), and a gate valve f (28) is installed on the pipeline.

6. The waste heat recovery and energy-saving equipment for a hydrolysis-to-ethylene glycol production unit according to claim 1, characterized in that, An ethylene glycol refining tower reflux tank (24) is provided on one side of the top cooler (25) of the ethylene glycol refining tower. The outlet of the top cooler (25) of the ethylene glycol refining tower is connected to the inlet of the reflux tank (24) of the ethylene glycol refining tower through a pipeline. An ethylene glycol refining tower reflux pump (23) is provided on one side of the reflux tank (24). The outlet of the reflux tank (24) of the ethylene glycol refining tower is connected to the inlet of the reflux pump (23) of the ethylene glycol refining tower through a pipeline. The outlet of the reflux pump (23) of the ethylene glycol refining tower is connected to the ethylene glycol refining tower (16) through a pipeline, and a gate valve b (17) is provided on the pipeline.

7. The waste heat recovery and energy-saving equipment for a hydrolysis-to-ethylene glycol production unit according to claim 1, characterized in that, A bypass pipeline is installed on the pipeline between the ethylene glycol refining tower reflux pump (23) and the ethylene glycol refining tower (16), and a flow meter f (22) and a flow control valve f (21) are installed on the bypass pipeline.

8. The waste heat recovery and energy-saving equipment for a hydrolysis-to-ethylene glycol production unit according to claim 1, characterized in that, The bottom of the ethylene glycol refining tower (16) is equipped with a pipeline and a gate valve c (20) is installed on the pipeline.

9. The waste heat recovery and energy-saving equipment for a hydrolysis-to-ethylene glycol production unit according to claim 1, characterized in that, A bypass pipeline is provided between the reflux tank (24) of the ethylene glycol refining tower and the top cooler (25) of the ethylene glycol refining tower, and the bypass pipeline is connected to the waste heat recovery booster (13). A gate valve e (27) is provided on the bypass pipeline.

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