Novel energy-saving and consumption-reducing device for ethylene oxide-ethylene glycol (EO-EG) decarbonization unit

Abstract

The utility model discloses a novel ethylene oxide-ethylene glycol (EO-EG) decarbonization unit energy-saving and consumption-reducing device which comprises a regeneration tower, the output end of the regeneration tower is connected with a carbonate solution low-pressure flash steam stripping tower, and the output end of the carbonate solution low-pressure flash steam stripping tower is connected with a carbonate solution pump. The top of a carbonate solution low-pressure flash steam stripping tower is connected with a steam jet pump, the output end of a carbonate solution pump is connected with a barren liquor / rich liquor exchanger, the output end of the barren liquor / rich liquor exchanger is connected with a circulating gas / barren liquor exchanger, the input end of the top of a regeneration tower is connected with a regenerator condensate tank, and the output end of the regeneration tower is connected with a heat exchanger. Relates to the technical field of ethylene oxide-ethylene glycol (EO-EG) decarburization devices, and realizes effective control of CO2 in circulation and reduction of carbonate circulation volume and steam consumption by controlling the influence of pH change of polymeric ionic acid radicals of vanadium element in a solution on the overall absorption rate of carbonate, so as to control the concentration of CO2 in circulation gas, save energy and reduce consumption.

Description

Technical Field

[0001] The utility model relates to the technical field of ethylene oxide-ethylene glycol (EO-EG) decarbonization devices, in particular to a novel ethylene oxide-ethylene glycol (EO-EG) decarbonization unit energy-saving and consumption-reducing device. Background Art

[0002] Ethylene oxide / ethylene glycol (EO / EG) mainly has the ethylene method, which uses ethylene and oxygen as raw materials, and generates ethylene oxide through oxidation reaction. Ethylene oxide is converted into ethylene glycol through traditional hydration process or catalytic hydrolysis process. At present, the dominant process for industrial application of ethylene oxide in the world is the direct oxidation of ethylene over silver catalyst to generate ethylene oxide and the hydration of ethylene oxide to generate ethylene glycol.

[0003] The CO2 removal system is one of the important units of EO / EG. Its main function is to remove the reaction by-product CO2 in the reaction circulating gas so that the CO2 component concentration in the circulating gas system is maintained within the specified range of the silver catalyst. In the existing process, the CO2 component concentration in the circulating gas at the top of the contact tower is high, the potassium bicarbonate concentration at the bottom of the regeneration tower is high, the circulation volume of potassium carbonate solution is large, the amount of steam required for regeneration is large, and the power consumption is high. Utility Model Content

[0004] The utility model aims to provide a novel ethylene oxide-ethylene glycol (EO-EG) decarbonization unit energy-saving and consumption-reducing device to solve the problems raised in the above-mentioned background technology.

[0005] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0006] A new type of ethylene oxide-ethylene glycol (EO-EG) decarbonization unit energy saving and consumption reduction device,

[0007] In a preferred embodiment of the utility model, a regeneration tower is included, characterized in that the output end of the regeneration tower is connected to a carbonate solution low-pressure flash steam stripping tower, and the output end of the carbonate solution low-pressure flash steam stripping tower is connected to a carbonate solution pump;

[0008] The top of the carbonate solution low-pressure flash steam stripping tower is connected to a steam jet pump, the output end of the carbonate solution pump is connected to a lean liquid / rich liquid exchanger, the output end of the lean liquid / rich liquid exchanger is connected to a circulating gas / lean liquid exchanger, and the output end of the circulating gas / lean liquid exchanger is connected to a contact tower;

[0009] The top input end of the regeneration tower is connected to the regenerator condensate tank, the output end of the regeneration tower is connected to the heat exchanger, the output end of the heat exchanger is connected to the reflux tank and the MEG recovery tower, the reflux tank and the MEG recovery tower are integrated equipment, and the reflux tank and the MEG recovery tower include a reflux tank and a MEG recovery tower.

[0010] In a preferred embodiment of the utility model, the circulating gas output end of the circulating gas / lean liquid exchanger is connected to the gas-liquid separation tank, the gas-liquid separation tank output end is connected to the circulating gas compressor, and the circulating gas compressor output end is connected to the oxygen mixer input end.

[0011] In a preferred embodiment of the utility model, the top of the washing tower is connected to a washing liquid cooler, and the washing liquid cooler is provided with a circulating water and a chilled water system, and the circulating water and the chilled water system are used to switch the circulating water and the chilled water.

[0012] In a preferred embodiment of the present invention, a steam source is arranged at the bottom of the carbonate solution low-pressure flash steam stripping tower, which is heated by a low-temperature heat source, and the operating pressure of the carbonate solution low-pressure flash steam stripping tower is: -50KPa(G)-20KPa(G).

[0013] In a preferred embodiment of the present invention, the carbonate solution low-pressure flash steam stripping tower and the regeneration tower are integrated equipment in the same shell, and the steam jet pump and the regeneration tower are connected by a water seal with a water seal height of 2-4m.

[0014] In a preferred embodiment of the present invention, a demister is provided at the outlet of the carbonate solution low-pressure flash steam stripping tower.

[0015] In a preferred embodiment of the present invention, a reboiler may be provided at the bottom of the carbonate solution low-pressure flash steam stripping tower, and the reboiler is a vertical shell-and-tube type.

[0016] The method for using the new ethylene oxide-ethylene glycol EO-EG decarbonization unit energy-saving and consumption-reducing device includes the following specific operating steps:

[0017] S1: Add carbonate solution and potassium carbonate solution into the regeneration tower, MEG 3.25wt%, K2CO3 12.43wt%, KHCO3 11.73wt% in the carbonate solution, the equivalent potassium carbonate concentration is 20-25%, and the KHCO3 concentration can be as low as below 10.35wt%;

[0018] S2: The lean carbonate solution is discharged from the bottom output end of the regeneration tower and enters the carbonate solution low-pressure flash steam stripping tower. A new composite solvent is input into the carbonate solution low-pressure flash steam stripping tower. The new composite solvent includes a stabilizer and pyrovanadate (V207 4- ), the pH value of the composite solvent is controlled at 10.6-X, the mass concentration of V2O5 is controlled at 1wt%-2.5wt%, and the pyrovanadate (V207 4-) The pH value is controlled by the solution preparation sequence and concentration. The concentration of K2CO3 is controlled at 24%-27%. K2BO3 is added to adjust the pH value to <12. V2O5 and the concentration of the blending agent are increased by <2.5wt%. The pH is controlled at 10.6-X. The pH value is adjusted to improve the absorption efficiency. The concentrations of K2CO3, K2BO3 and V2O5 are adjusted according to the maximum absorption rate, thereby reducing the CO2 concentration in the circulating gas, reducing the carbonate circulation amount, saving the steam consumption of the regeneration tower and the power consumption of the circulating pump, and reducing the power consumption. 20-25% lower, 10-20% steam saving, stripping steam is introduced into the bottom of the carbonate solution low-pressure flash steam stripping tower, and steam containing a small amount of CO2 is discharged from the top of the carbonate solution low-pressure flash steam stripping tower, and after being pressurized by a steam jet pump, it enters the upper atmospheric pressure regeneration tower for secondary utilization. The typical contents of the lean carbonate solution are H2O86.12mol%, MEG6.05mol%, K2CO32.11mol%, KHCO33.52mol%, and the equivalent potassium carbonate concentration is 20-25%;

[0019] S3: The lean carbonate solution in the carbonate solution low-pressure flash stripping tower is transported to the lean liquid / rich liquid exchanger by a carbonate solution pump, and the rich liquid is transported to the lean liquid / rich liquid exchanger at the bottom of the contact tower for heat exchange;

[0020] S4: The circulating gas at the top of the contact tower and the lean carbonate solution of the lean liquid / rich liquid exchanger are heat exchanged in the circulating gas / lean liquid exchanger. The circulating gas temperature at the top of the washing tower is 42°C. The circulating gas temperature after heat exchange in the circulating gas / lean liquid exchanger 7 is 63°C. The circulating gas is discharged from the output end of the circulating gas / lean liquid exchanger and enters the gas-liquid separation tank. The circulating gas is then separated by the gas-liquid separation tank and transported to the circulating gas compressor, and then transported to the oxygen mixer inlet by the circulating gas compressor.

[0021] S5: The circulating liquid and rich circulating gas are input into the lower section of the contact tower, and the lower section of the contact tower transports the washed circulating liquid to the washing liquid cooler through the washing circulating pump;

[0022] S6: The lean carbonate solution at the output end of the lean liquid / rich liquid exchanger is transported to the flash tank for circulation, then enters the secondary flash tank through the flash tank, and flows to the regeneration tower again for recycling;

[0023] S7: The CO2 discharged from the regeneration tower is discharged to the heat exchanger, and then transported to the reflux tank and the reflux tank in the MEG recovery tower through the heat exchanger, and the desalted water is replenished in the reflux tank. The delivery end of the MEG recovery tower transports the CO2 to the CO2 recovery unit;

[0024] S8: The ethylene glycol is recovered by the ethylene glycol recovery pump at the output end of the reflux tank, so that the ethylene glycol is discharged into the ethylene glycol distillation system, and the condensate is recovered by the condensate recovery pump and transported to the condensate cooler. The condensate is refluxed to the MEG recovery tower at the output end of the condensate cooler. At the same time, the condensate in the output end of the condensate cooler can be connected to the external discharge pipe for external discharge.

[0025] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention.

[0026] 1. By controlling the pH change of the vanadium element in the solution and the effect on the overall absorption rate of carbonate, the CO2 in the cycle can be effectively controlled and the carbonate circulation volume and steam consumption can be reduced, thereby controlling the CO2 concentration in the circulating gas and saving energy and reducing consumption;

[0027] 2. By integrating the reflux tank and the MEG recovery tower, the MEG discharge volume can be reduced to zero. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0029] Figure 1 This is a schematic diagram of the work flow structure of a new type of ethylene oxide-ethylene glycol (EO-EG) decarbonization unit energy-saving and consumption-reducing device.

[0030] In the figure: regeneration tower 1, carbonate solution low-pressure flash steam stripping tower 2, steam jet pump 3, carbonate solution pump 4, lean liquid / rich liquid exchanger 5, contact tower 6, circulating gas / lean liquid exchanger 7, gas-liquid separation tank 8, circulating gas compressor 9, flash tank 10, secondary flash tank 11, heat exchanger 12, reflux tank and MEG recovery tower 13, ethylene glycol recovery pump 14, condensate recovery pump 15, condensate cooler 16, washing liquid cooler 17. DETAILED DESCRIPTION

[0031] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0032] Example 1: Figure 1 , comprising a regeneration tower 1, the output end of the regeneration tower 1 is connected to a carbonate solution low-pressure flash steam stripping tower 2, and the output end of the carbonate solution low-pressure flash steam stripping tower 2 is connected to a carbonate solution pump 4;

[0033] The top of the carbonate solution low-pressure flash steam stripping tower 2 is connected to a steam jet pump 3, the output end of the carbonate solution pump 4 is connected to a lean liquid / rich liquid exchanger 5, and the output end of the lean liquid / rich liquid exchanger 5 is connected to a contact tower 6;

[0034] The top input end of the regeneration tower 1 is connected to the regenerator condensate tank 11, the output end of the regeneration tower 1 is connected to the heat exchanger 12, the output end of the heat exchanger 12 is connected to the reflux tank and MEG recovery tower 13, the reflux tank and the MEG recovery tower 13 are integrated equipment, and the reflux tank and the MEG recovery tower 13 include a reflux tank and a MEG recovery tower.

[0035] The specific usage scenario of this embodiment is: a trace amount of CO2 in the lean carbonate solution is flashed off and enters the lower section of the regeneration tower 1, and is discharged together with the CO2 removed from the regeneration tower 1, and stripping steam is introduced into the bottom of the carbonate solution low-pressure flash steam stripping tower 2, and steam containing a small amount of CO2 is discharged from the top of the carbonate solution low-pressure flash steam stripping tower 2, and after being pressurized by the steam jet pump 3 or the steam compressor, it enters the upper normal pressure regeneration tower 1 for secondary utilization, and the lean carbonate solution contains 86.12 mol% H2O, 6.05 mol% MEG, 2.11 mol% K2CO3, 3.52 mol% KHCO3, and an equivalent potassium carbonate concentration of 20-25%. A steam source is set at the bottom of the carbonate solution low-pressure flash steam stripping tower 2, and is heated by a low-temperature heat source. The lean carbonate is heated by the steam source, and the carbonate solution low-pressure flash steam stripping tower 2 The operating pressure is: -50KPa(G)-20KPa(G), MEG3.25wt%, K2CO312.43wt%; KHCO311.73wt% in a typical carbonate solution, the equivalent potassium carbonate concentration is 20-25%, and the KHCO3 concentration can be as low as below 10.35wt%. The flash steam stripping tower and the regeneration tower are integrated equipment with the same shell, and the reflux tank and the MEG recovery tower 13 are integrated equipment, so that the MEG discharge volume is zero, and the discharged CO2 enters the CO2 recovery system. A partition is provided in the reflux tank, and a condensate cooler and a condensate discharge pipe are provided in the reflux pipe of the condensate pump. The recovery tower is a packed tower with a packing height of 7m. A demister is provided on the top, and spray facilities and a water cooler are provided. The top temperature of the tower is not more than 60°C, and the MEG in the condensate water is not more than 0.01wt%, and it is discharged regularly, and a desalted water system is provided for regular replenishment.

[0036] Example 2: Figure 1 The circulating gas output end of the circulating gas / lean liquid exchanger 7 is connected to the gas-liquid separation tank 8, the output end of the gas-liquid separation tank 8 is connected to the circulating gas compressor 9, and the output end of the circulating gas compressor 9 is connected to the input end of the oxygen mixer;

[0037] The top of the contact tower 6 is connected to a washing liquid cooler 17, and the washing liquid cooler 17 is provided with a circulating water and a chilled water system, and the circulating water and the chilled water system are used to switch the circulating water and the chilled water;

[0038] The carbonate solution low-pressure flash steam stripping tower 2 and the regeneration tower 1 are integrated equipment in the same shell, and the steam jet pump 3 is connected to the regeneration tower 1 through a water seal with a water seal height of 2-4m.

[0039] The specific usage scenario of this embodiment is: the circulating gas at the top of the contact tower 6 and the lean carbonate solution of the lean liquid / rich liquid exchanger 5 are heat exchanged in the circulating gas / lean liquid exchanger 7, the circulating gas is separated by the gas-liquid separation tank 8 and transported to the circulating gas compressor 9, and transported to the oxygen mixer inlet through the circulating gas compressor 9. The CO2 concentration of the circulating gas at the reactor inlet is lower than 0.7 mol% at the initial and final stages of the reaction, and is controlled at 0.28 mol%-0.7 mol%. The washing liquid cooler 17 is provided with a circulating water and a chilled water system. The circulating water and the chilled water can be switched according to temperature requirements to ensure the temperature while ensuring that the water content in the circulating gas is not more than 0.29 mol%. The bottom input end of the washing liquid cooler 17 is provided with a chilled water inlet and a cooling water inlet, and the top output end of the washing liquid cooler 17 is provided with a chilled water return and a cooling water return.

[0040] Example 3: Figure 1 A demister (not marked in the figure) is provided at the outlet of the carbonate solution low-pressure flash steam stripping tower 2, and a reboiler (not marked in the figure) can be provided at the bottom of the carbonate solution low-pressure flash steam stripping tower 2, and the reboiler is a vertical shell-and-tube type.

[0041] The specific usage scenario of this embodiment is: a defoamer is provided to eliminate foam, and a reboiler is provided to heat the carbonate solution;

[0042] The method for using the novel ethylene oxide-ethylene glycol EO-EG decarbonization unit energy-saving and consumption-reducing device is characterized in that the specific operation steps are as follows:

[0043] S1: Add carbonate solution and potassium carbonate solution into regeneration tower 1, MEG 3.25wt%, K2CO3 12.43wt%, KHCO3 11.73wt% in carbonate solution, equivalent potassium carbonate concentration is 20-25%, equivalent potassium carbonate concentration is 20-25%, and KHCO3 concentration can be as low as below 10.35wt%;

[0044] S2: The lean carbonate solution is discharged from the bottom output end of the regeneration tower 1 and enters the carbonate solution low-pressure flash steam stripping tower 2. The carbonate solution low-pressure flash steam stripping tower 2 is input with a new composite solvent. The new composite solvent includes a stabilizer and pyrovanadate (V207 4- ), the pH value of the composite solvent is controlled at 10.6-X, the mass concentration of V2O5 is controlled at 1wt%-2.5wt%, and the pyrovanadate (V207 4-) The pH value is controlled by the solution preparation sequence and concentration. The concentration of K2CO3 is controlled at 24%-27%. K2BO3 is added to adjust the pH value to <12. V2O5 and the concentration of the blending agent are increased by <2.5wt%. The pH is controlled at 10.6-X. The pH value is adjusted to improve the absorption efficiency. The concentrations of K2CO3, K2BO3 and V2O5 are adjusted according to the maximum absorption rate, thereby reducing the CO2 concentration in the circulating gas and reducing the carbonate circulation volume. The steam consumption of the regeneration tower and the power consumption of the circulating pump are saved, and the power consumption is reduced. 20-25%, steam saving 10-20%, stripping steam is introduced into the bottom of carbonate solution low-pressure flash steam stripping tower 2, and steam containing a small amount of CO2 is discharged from the top of carbonate solution low-pressure flash steam stripping tower 2, and after being pressurized by steam jet pump 3, it enters the upper atmospheric pressure regeneration tower for secondary utilization. The typical contents of lean carbonate solution are H2O86.12mol%, MEG6.05mol%, K2CO32.11mol%, KHCO33.52mol%, and the equivalent potassium carbonate concentration is 20-25%;

[0045] S3: The lean carbonate solution in the carbonate solution low-pressure flash steam stripping tower 2 is transported to the lean liquid / rich liquid exchanger 5 through the carbonate solution pump 4, and the rich liquid is transported to the lean liquid / rich liquid exchanger 5 at the bottom of the contact tower 6 for heat exchange;

[0046] S4: The circulating gas at the top of the contact tower 6 and the lean carbonate solution of the lean liquid / rich liquid exchanger 5 are heat exchanged in the circulating gas / lean liquid exchanger 7. The circulating gas temperature at the top of the contact tower 6 is 42°C. The circulating gas temperature after heat exchange in the circulating gas / lean liquid exchanger 7 is 63°C. The circulating gas discharged from the output end of the circulating gas / lean liquid exchanger 7 enters the gas-liquid separation tank 8. The circulating gas is then separated by the gas-liquid separation tank 8 and transported to the circulating gas compressor 9. The circulating gas is then transported to the oxygen mixer inlet by the circulating gas compressor 9.

[0047] S5: The circulating liquid and rich circulating gas are input into the lower section of the contact tower, and the lower section of the contact tower delivers the washed circulating liquid to the washing liquid cooler 17 through the washing circulating pump;

[0048] S6: The lean carbonate solution at the output end of the lean liquid / rich liquid exchanger 5 is transported to the flash tank 10 for circulation, and then enters the secondary flash tank 11 through the flash tank 10, and flows to the regeneration tower 1 again for recycling;

[0049] S7: The CO2 discharged from the regeneration tower 1 is discharged to the heat exchanger 12, and then transported to the reflux tank and the reflux tank in the MEG recovery tower 13 through the heat exchanger 12, and the desalted water is replenished in the reflux tank. The delivery end of the MEG recovery tower 13 transports the CO2 to the CO2 recovery unit;

[0050] S8: The ethylene glycol is recovered by the ethylene glycol recovery pump 14 at the output end of the reflux tank, so that the ethylene glycol is discharged into the ethylene glycol distillation system, and the condensate is recovered by the condensate recovery pump 15, and the condensate is transported to the condensate cooler 16. The condensate at the output end of the condensate cooler 16 flows back to the MEG recovery tower 13, and the condensate in the output end of the condensate cooler 16 can be connected to the external discharge pipe for external discharge.

[0051] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A novel ethylene oxide-ethylene glycol (EO-EG) decarbonization unit energy-saving and consumption-reducing device, comprising a regeneration tower (1), It is characterized in that The output end of the regeneration tower (1) is connected to the carbonate solution low-pressure flash steam stripping tower (2), and the output end of the carbonate solution low-pressure flash steam stripping tower (2) is connected to the carbonate solution pump (4); The top of the carbonate solution low-pressure flash steam stripping tower (2) is connected to a steam jet pump (3), the output end of the carbonate solution pump (4) is connected to a lean liquid / rich liquid exchanger (5), the output end of the lean liquid / rich liquid exchanger (5) is connected to a circulating gas / lean liquid exchanger (7), and the output end of the circulating gas / lean liquid exchanger (7) is connected to a contact tower (6); The top input end of the regeneration tower (1) is connected to the regenerator condensate tank (11), the output end of the regeneration tower (1) is connected to the heat exchanger (12), the output end of the heat exchanger (12) is connected to the reflux tank and the MEG recovery tower (13), the reflux tank and the MEG recovery tower (13) are integrated equipment, and the reflux tank and the MEG recovery tower (13) include a reflux tank and a MEG recovery tower.

2. A novel ethylene oxide-ethylene glycol (EO-EG) decarbonization unit energy-saving and consumption-reducing device according to claim 1, It is characterized in that The circulating gas output end of the circulating gas / lean liquid exchanger (7) is connected to a gas-liquid separation tank (8), the output end of the gas-liquid separation tank (8) is connected to a circulating gas compressor (9), and the output end of the circulating gas compressor (9) is connected to an oxygen mixer input end.

3. A novel ethylene oxide-ethylene glycol (EO-EG) decarbonization unit energy-saving and consumption-reducing device according to claim 2, It is characterized in that The top of the contact tower (6) is connected to a washing liquid cooler (17), and the washing liquid cooler (17) is provided with a circulating water and a chilled water system, and the circulating water and the chilled water system are used to switch the circulating water and the chilled water.

4. A novel ethylene oxide-ethylene glycol (EO-EG) decarbonization unit energy-saving and consumption-reducing device according to claim 1, It is characterized in that A steam source is arranged at the bottom of the carbonate solution low-pressure flash steam stripping tower (2) and heated by a low-temperature heat source. The operating pressure of the carbonate solution low-pressure flash steam stripping tower (2) is: -50KPa(G)-20KPa(G).

5. A novel ethylene oxide-ethylene glycol (EO-EG) decarbonization unit energy-saving and consumption-reducing device according to claim 1, It is characterized in that The carbonate solution low-pressure flash steam stripping tower (2) and the regeneration tower (1) are integrated equipment in the same shell, and the steam jet pump (3) and the regeneration tower (1) are connected via a water seal, with a water seal height of 2-4 m.

6. A novel ethylene oxide-ethylene glycol (EO-EG) decarbonization unit energy-saving and consumption-reducing device according to claim 1, It is characterized in that The carbonate solution low-pressure flash steam stripping tower (2) is provided with a demister at its outlet.

7. A novel ethylene oxide-ethylene glycol (EO-EG) decarbonization unit energy-saving and consumption-reducing device according to claim 6, It is characterized in that A reboiler may be arranged at the bottom of the carbonate solution low-pressure flash steam stripping tower (2), and the reboiler is a vertical shell-and-tube type.

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