Ethylene oxide and ethylene glycol APC control energy-saving system

Abstract

The utility model discloses an ethylene oxide and ethylene glycol APC (automatic process control) energy-saving device, which belongs to the technical field of chemical energy-saving equipment and comprises an APC master controller, and the APC master controller comprises an ethylene oxide section master controller and an ethylene glycol section master controller. The ethylene oxide section main controller comprises an ethylene oxide reaction main controller, a carbon dioxide removal main controller and an ethylene oxide refining main controller; the ethylene glycol working section main controller comprises an ethylene glycol reaction dehydration main controller and an ethylene glycol refining main controller; the ethylene oxide reaction main controller comprises an ethylene oxide reaction sub-controller and a boiler water replenishing sub-controller; the carbon dioxide removal main controller comprises a carbon dioxide removal sub-controller and a membrane recovery sub-controller; the ethylene oxide refining recovery main controller comprises an ethylene oxide recovery sub-controller and an ethylene oxide refining sub-controller, and is mainly applied to the aspect of chemical production.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the chemical energy saving technical field, specifically relates to a kind of ethylene oxide ethylene glycol APC control energy-saving system. BACKGROUND

[0002] The applicant EOEG device adopts Shell technology, and is designed based on Shell / CRI S-892 high selectivity catalyst, to produce ethylene oxide by direct oxidation method, and the oxidation reaction is carried out in a fixed bed reactor with silver catalyst in the shell, and the reaction heat is removed by shell boiler water, and steam is by-produced.

[0003] Part of the generated ethylene oxide is refined to obtain high-purity EO product after absorption and resolution, and part of the ethylene oxide and water are directly hydrated to generate ethylene glycol in a tubular reactor, and after evaporation and dehydration, vacuum rectification is carried out to obtain high-quality products of monoethylene glycol (MEG), diethylene glycol (DEG) and triethylene glycol (TEG).

[0004] The device process mainly consists of an EO reaction system, a CO2 removal and EO recovery system, a light component removal and EO refining system, an EG reaction and evaporation system, an EG refining system, a deoxygenated water and quenching water system, an intermediate tank area, and a utility system unit.

[0005] The applicant hopes to improve the stability and safety of the device operation by implementing advanced control, further tap the potential of the device, stabilize the product quality, and save energy and reduce consumption.

[0006] Based on careful on-site investigation, historical data analysis and step test, repeated discussion with device technical personnel and operators, and previous engineering implementation experience, the following design scheme is formed. CONTENT OF THE UTILITY MODEL

[0007] To solve the above technical problems, the technical scheme adopted by the ethylene oxide absorption system energy-saving device is as follows:

[0008] An ethylene oxide ethylene glycol APC control energy-saving system, characterized by comprising an APC general controller, wherein the APC general controller comprises an ethylene oxide section main controller and an ethylene glycol section main controller.

[0009] The ethylene oxide section main controller comprises an ethylene oxide reaction main controller, a carbon dioxide removal main controller and an ethylene oxide refining main controller.

[0010] The ethylene glycol section main controller comprises an ethylene glycol reaction dehydration main controller and an ethylene glycol refining main controller.

[0011] The ethylene oxide reaction main controller comprises an ethylene oxide reaction sub-controller and a boiler water replenishment sub-controller.

[0012] The carbon dioxide removal main controller comprises a carbon dioxide removal sub-controller and a membrane recovery sub-controller;

[0013] The ethylene oxide refining recovery main controller comprises an ethylene oxide recovery sub-control and an ethylene oxide refining sub-controller;

[0014] The ethylene glycol reaction dehydration main controller comprises an ethylene glycol reaction sub-controller, a four-effect evaporation sub-controller, an ethylene glycol pre-dehydration sub-controller, an ethylene glycol dehydration sub-controller and an ethylene glycol discharge flash sub-controller;

[0015] The ethylene glycol refining main controller comprises an ethylene glycol refining sub-controller, an ethylene glycol circulation sub-controller, a diethylene glycol recovery sub-controller and a triethylene glycol refining sub-controller.

[0016] Preferably: the ethylene content and the oxygen content are stably controlled. The oxygen content at the reactor inlet is controlled to improve the EO selectivity under the constraint of meeting the explosion limit.

[0017] Preferably: the liquid level of the boiler feedwater system is stably controlled, and the labor intensity of the operator is reduced.

[0018] Preferably: the key temperature of the quenching discharge unit is stably controlled, and the steam consumption is saved.

[0019] Preferably: for the EO refining unit, the heat added by the reboiler, the EO production and the column bottom production are coordinated, the column temperature and the liquid level are stably controlled. On the basis of ensuring product qualification, the reflux ratio is optimized, the EO production is increased and the steam consumption is reduced.

[0020] Preferably: the end temperature of the hydration reactor is controlled to stably control the hydration ratio.

[0021] Preferably: the coordinated control of multi-effect evaporation is realized. The top pressure of each absorption tower is relatively stably controlled. Multi-stage balanced distribution is realized, so that 2.5MPa steam of the first-effect evaporation reboiler is saved. At the same time, the liquid levels of the towers are stably controlled.

[0022] Preferably: for the EG refining unit, the reboiling steam and the column bottom production are coordinated to stably control the temperature and the liquid level of each tower. At the same time, on the basis of ensuring product qualification, the steam consumption is reduced.

[0023] How to prove that the system has energy-saving effect needs corresponding data to prove. What is the energy consumption when the system is not used, and what is the energy consumption when the system is used. In this way, a corresponding closed loop is formed.

[0024] The new utility has the following advantages:

[0025] The utility model provides an energy -conserving device of ethylene oxide ethylene glycol APC control, equipment investment is small, to the parameter optimization of the EO reaction unit, boiler feed water unit, CO2 removal unit, EO recovery unit, EO quenching discharge unit, EO refining unit, hydration reaction unit, four -effect evaporation unit, EG dewatering unit, EG discharge flash evaporation unit, MEG refining unit, DEG refining unit, TEG refining unit of device, fine control, guarantee variable not over constraint, ensure safe production, improve the basic loop automatic control rate and the stable rate, improve the device operation automation level and safety, avoid the safety accident caused by artificial misoperation, on the basis of guaranteeing product qualified, card edge control, reduce steam consumption reaches the purpose of reducing the energy consumption of device, is suitable for overall popularization and application. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The utility model provides a work flow chart.

[0027] In the drawing: 1. APC total controller, 2. Ethylene oxide section main controller, 3. Ethylene glycol section main controller, 4. Ethylene oxide reaction main controller, 5. Carbon dioxide removal main controller, 6. Ethylene oxide refining main controller, 7. Ethylene glycol reaction dehydration main controller, 8. Ethylene glycol refining main controller, 9. Ethylene oxide reaction sub-controller, 10. Boiler water supply sub-controller, 11. Carbon dioxide removal sub-controller, 12. Membrane recovery sub-controller, 13. Ethylene oxide recovery sub-controller, 14. Ethylene oxide refining sub-controller, 15. Ethylene glycol reaction sub-controller, 16. Four-effect evaporation sub-controller, 17. Ethylene glycol predehydration sub-controller, 18. Ethylene glycol dehydration sub-controller, 19. Ethylene glycol discharge flash evaporation sub-controller, 20. Ethylene glycol refining sub-controller, 21. Ethylene glycol circulation sub-controller, 22. Diethylene glycol recovery sub-controller, 23. Triethylene glycol refining sub-controller. DETAILED DESCRIPTION

[0028] Example 1

[0029] As Figure 1 shown:

[0030] An ethylene oxide ethylene glycol APC control energy -conserving system, it is characterized in including APC total controller 1,

[0031] APC total controller 1 includes ethylene oxide section main controller 2 and ethylene glycol section main controller 3;

[0032] Ethylene oxide section main controller 2 includes ethylene oxide reaction main controller 4, carbon dioxide removal main controller 5 and ethylene oxide refining main controller 6;

[0033] Ethylene glycol section main controller 3 includes ethylene glycol reaction dehydration main controller 7 and ethylene glycol refining main controller 8;

[0034] The ethylene oxide reaction main controller 4 comprises an ethylene oxide reaction sub-controller 9 and a boiler feed water sub-controller 10;

[0035] The carbon dioxide removal main controller 5 comprises a carbon dioxide removal sub-controller 11 and a membrane recovery sub-controller 12;

[0036] The ethylene oxide refining recovery main controller 6 comprises an ethylene oxide recovery sub-controller 13 and an ethylene oxide refining sub-controller 14;

[0037] The ethylene glycol reaction dehydration main controller 7 comprises an ethylene glycol reaction sub-controller 15, a four-effect evaporation sub-controller 16, an ethylene glycol pre-dehydration sub-controller 17, an ethylene glycol dehydration sub-controller 18 and an ethylene glycol discharge flash sub-controller 19;

[0038] The ethylene glycol refining main controller 8 comprises an ethylene glycol refining sub-controller 20, an ethylene glycol circulation sub-controller 21, a diethylene glycol recovery sub-controller 22 and a triethylene glycol refining sub-controller 23.

[0039] The working principle of the utility model is as follows:

[0040] Stable control of ethylene content and oxygen content. Under the constraint of meeting the explosion limit, the oxygen content at the reactor inlet is controlled, and the EO selectivity is improved. Stable control of the liquid level of the boiler feed water system reduces the labor intensity of the operator. Under the premise of meeting the CO2 content control requirements, steam consumption is saved. The circulating gas pressure is stable.

[0041] In the EO absorption and resolution unit, the requirements of temperature and liquid level coordination control of each tower are met, and steam and absorption water consumption is saved. The key temperature of the quenching discharge unit is stable, and steam consumption is saved. For the EO refining unit, the heat added by the reboiler, the EO extraction and the tower bottom extraction are coordinated, and the tower temperature and liquid level are stable. On the basis of ensuring product qualification, the reflux ratio is optimized, the EO extraction amount is increased and the steam consumption is reduced. The end temperature of the hydration reactor is controlled to realize stable control of the hydration ratio. The coordination control of multi-effect evaporation is realized. The top pressure of each absorption tower is relatively stable. At the same time, the liquid level of each tower is stable. For the EG refining unit, the reboiler steam and the tower bottom extraction are coordinated to ensure stable control of the temperature and liquid level of each tower. At the same time, on the basis of ensuring product qualification, the steam consumption is reduced.

[0042] In addition, it should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the specification is described in this way only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that those skilled in the art can understand.

Claims

1. An oxirane glycol APC control energy saving system, characterized by, The APC general controller (1) comprises an ethylene oxide section main controller (2) and a glycol section main controller (3); The ethylene oxide section main controller (2) comprises an ethylene oxide reaction main controller (4), a carbon dioxide removal main controller (5) and an ethylene oxide refining main controller (6); The glycol section main controller (3) comprises a glycol reaction dehydration main controller (7) and a glycol refining main controller (8); The ethylene oxide reaction main controller (4) comprises an ethylene oxide reaction sub-controller (9) and a boiler water replenishment sub-controller (10); The carbon dioxide removal main controller (5) comprises a carbon dioxide removal sub-controller (11) and a membrane recovery sub-controller (12); The ethylene oxide refining main controller (6) comprises an ethylene oxide recovery sub-controller (13) and an ethylene oxide refining sub-controller (14); The glycol reaction dehydration main controller (7) comprises a glycol reaction sub-controller (15), a four-effect evaporation sub-controller (16), a glycol pre-dehydration sub-controller (17), a glycol dehydration sub-controller (18) and a glycol discharge flash sub-controller (19); The glycol refining main controller (8) comprises a glycol refining sub-controller (20), a glycol circulation sub-controller (21), a diethylene glycol recovery sub-controller (22) and a triethylene glycol refining sub-controller (23). ​

Images