A method and device for reducing the amount of grease in an ethylene cracking gas deacidification unit

Abstract

The application discloses a method and device for reducing the amount of butter in an ethylene cracking gas deacid gas unit. The method comprises the following steps: inputting ethylene cracking gas, lean amine liquid and defoaming agent into a stator-rotor reactor, mixing them in the stator and the rotor, outputting gas phase and liquid phase from the stator-rotor reactor after removing the acid gas, the liquid phase being rich amine liquid, the rich amine liquid and washing oil entering an ultra-gravity reactor to be washed, then the rich amine liquid and the washing oil entering a separation unit to be separated, and the separated rich amine liquid being regenerated into lean amine liquid and entering the stator-rotor reactor to be recycled. Compared with the prior art, the method can reduce the generation of butter, and due to the effect of strong shearing, the reactor is not prone to be blocked, and the stability of the ethylene cracking gas deacid gas unit can be enhanced.

Description

Technical Field

[0001] This invention relates to the field of gas purification, specifically to a method and apparatus for reducing the amount of butter in an ethylene cracking gas deacidification unit. Background Technology

[0002] Ethylene is an important basic organic chemical raw material. The ethylene cracking gas leaving the cracking furnace typically contains a certain volume of acidic gas, mainly hydrogen sulfide and carbon dioxide. Hydrogen sulfide can poison the catalyst and cause corrosion of equipment and pipelines; carbon dioxide will condense during subsequent cryogenic separation, clogging pipelines, and will also accumulate in the circulating ethylene, reducing the partial pressure of ethylene and leading to a decrease in the molecular weight of the polymerization products. Therefore, it is necessary to remove the acidic gases from the cracking gas before it enters the separation process.

[0003] In industrial applications, acidic gases from the cracked gas are typically removed after three or four stages of compression using an alkaline washing process or a combined amine-alkali process. The concentrations of hydrogen sulfide and carbon dioxide in the cracked gas are strictly controlled to be no more than 1 μL / L. During alkaline washing, dienes condensed or dissolved in the alkaline or amine solution form free radicals under trace amounts of oxygen, initiating polymerization. Furthermore, aldehydes and ketones readily undergo condensation reactions under alkaline conditions, similarly forming polymers of a certain molecular weight, known as "butter." This butter not only reduces the efficiency of the alkaline or amine washing process but also clogs the alkaline / amine washing tower, causing instability in the deacidification gas unit.

[0004] To reduce the impact of butter formation on the deacidification gas unit, industry commonly uses butter inhibitors to decrease butter production and reduce the risk of butter blockage. However, butter inhibitors are expensive and cannot completely prevent the unstable operation of the ethylene cracking gas deacidification gas unit caused by butter blockage. Summary of the Invention

[0005] The purpose of this invention is to reduce the amount of grease in the deacidification gas unit of ethylene cracking gas by means of a method and apparatus for reducing grease production at the source and reducing the risk of grease blockage, thereby enhancing the stability of the deacidification gas unit.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] This invention provides a method for reducing the amount of butter in an ethylene cracking gas deacidification unit, comprising the following steps:

[0008] Ethylene cracking gas, lean amine liquid, and defoamer are fed into a stator-rotor reactor. The gas phase and liquid phase come into countercurrent contact inside the stator and rotor. After the acid gas is removed, the gas phase and liquid phase are output from the stator-rotor reactor, respectively.

[0009] The output liquid phase is a rich amine solution. The rich amine solution and the wash oil enter the high gravity reactor for oil washing. After that, the rich amine solution and the wash oil enter the separation unit for separation.

[0010] The separated amine-rich solution is regenerated into amine-poor solution, which is then recycled into the stator-rotor reactor.

[0011] Specifically, the ethylene cracking gas enters the reactor through the gas phase inlet of the stator-rotor reactor, the lean amine solution enters the reactor through the liquid phase inlet of the stator-rotor reactor, and the defoamer enters the reactor through an inlet arranged on the stator. Ethylene cracking gas, lean amine liquid, and defoamer are mixed inside the stator and rotor. Under the action of both, the liquid phase is sheared and torn into tiny liquid filaments, droplets, and liquid films, possessing a huge interphase mass transfer specific surface area and a rapid surface renewal rate, thus efficiently removing acidic gases from the ethylene cracking gas. After the acidic gases are removed, the gas and liquid phases leave the reactor from the gas and liquid phase outlets of the stator-rotor reactor, respectively. The liquid phase (rich amine liquid) leaving the stator-rotor reactor and the wash oil enter the reactor through the liquid phase inlet of the high-gravity reactor for oil washing. The rich amine liquid and wash oil are mixed inside the rotor. The high-speed rotating rotor breaks the oil and water phases into tiny droplets. Through continuous aggregation and dispersion, the mass transfer of hydrocarbons from the aqueous phase to the oil phase is completed. The hydrocarbons dissolved in the amine liquid are extracted into the wash oil. Then, the rich amine liquid and wash oil enter the separation unit for separation. The wash oil aggregates into the oil phase and leaves from the top of the separation unit. The rich amine liquid aggregates into the aqueous phase and leaves from the bottom of the separation unit.

[0012] According to the butter reduction method of the present invention, the liquid phase moves from the inside to the outside under the drive of the rotor. Preferably, the residence time of the gas phase and the liquid phase in the stator-rotor reactor cavity is ≤1s, that is, the residence time of ethylene cracking gas, lean amine liquid and defoamer in the stator-rotor reactor cavity is ≤1s. Because the contact time is very short, the mass transfer process of hydrocarbons into the amine liquid is effectively suppressed, the dissolution of hydrocarbons can be reduced, and the total amount of butter generated can be reduced from the source.

[0013] According to the butter reduction method of the present invention, preferably, the radial distance between the stator ring and the rotor ring of the stator-rotor reactor is 1 mm to 10 mm, more preferably 1 mm to 5 mm; the linear velocity of the outermost rotor is 20 m / s to 40 m / s, more preferably 30 m / s to 40 m / s. When the distance between the stator ring and the rotor ring is small and the relative velocity is large, a strong shear force is generated between the stator ring and the rotor ring, which can prevent the generated butter from depositing on the reactor internal components; for butter already adhering to the internal components, the strong shear force can force it to detach. Therefore, the stability of the reactor can be greatly enhanced, ensuring the removal efficiency of acidic gases.

[0014] According to the butter reduction method of the present invention, preferably, the defoamer enters the reactor through an additive inlet arranged on the stator of the stator-rotor reactor.

[0015] After the defoamer enters the reactor through the additive inlet, it impacts the amine solution to achieve initial mixing. Impurities present in the amine solution can cause it to foam, especially in the high shear environment inside the stator-rotor reactor, which makes foaming more likely. Therefore, it is necessary to add a defoamer to suppress foaming and ensure good removal efficiency.

[0016] According to the butter reduction method of the present invention, preferably, the defoamer is selected from one or more combinations of high molecular weight alcohols (such as polyalkylene diols, stearyl alcohol, etc.) and silicones (such as methyl silicone oil, etc.). The presence of the defoamer can suppress foaming of amine liquid in the strong shear environment of the deacidifying gas stator-rotor reactor or the oil washing high gravity reactor, and prevent the reduction of mixing mass transfer efficiency.

[0017] According to the butter reduction method of the present invention, preferably, the volume ratio of wash oil to amine-rich liquid is 1:10-20, more preferably 1:2-5. Because of the good mixing effect of the supergravity reactor, the ratio of wash oil to amine liquid is less than that of conventional oil washing, which can reduce operating costs.

[0018] According to the butter reduction method of the present invention, preferably, the wash oil is cracked gasoline or hydrogenated gasoline, preferably hydrogenated gasoline.

[0019] According to the butter reduction method of the present invention, preferably, the ethylene cracking gas originates from after the fourth stage compressor (five-stage compression process) or after the third stage compressor (four-stage compression process), more preferably after the fourth stage compressor (five-stage compression process).

[0020] According to the butter reduction method of the present invention, preferably, the ethylene cracked gas enters the reactor from the gas phase inlet of the stator-rotor reactor after heat exchange. After heat exchange, the temperature of the ethylene cracked gas increases, but does not exceed 45°C. After upstream compression and cooling steps, the temperature of the ethylene cracked gas fluctuates within a certain range depending on the temperature and flow rate of the cooling water. In order to reduce the condensation of heavy hydrocarbons when in contact with amine liquid, the temperature of the ethylene cracked gas is increased by heat exchange to reduce the possibility of heavy hydrocarbon condensation. However, when the temperature exceeds 45°C, the unsaturated hydrocarbons in the ethylene cracked gas are prone to polymerize, forming butter.

[0021] The lean amine solution, after being cooled by heat exchange, enters the reactor through the liquid phase inlet of the stator-rotor reactor. The temperature difference between the cooled solution and the ethylene cracked gas entering the reactor is ≤1℃. Reducing the temperature difference between the ethylene cracked gas and the amine solution prevents the condensation of heavy hydrocarbons and effectively reduces the formation of grease.

[0022] According to the butter reduction method of the present invention, preferably, the rich amine liquid separated by the separation unit exchanges heat with the regenerated lean amine liquid and then enters the regeneration unit for regeneration; after the regenerated lean amine liquid exchanges heat with the rich amine liquid separated by the separation unit and the ethylene cracking gas in sequence, the lean amine liquid is adjusted to a suitable temperature and then enters the stator-rotor reactor for recycling.

[0023] Another aspect of the present invention provides a butter reduction device for an ethylene cracking gas deacidification gas unit, for realizing the above-mentioned butter reduction method. The device includes: a stator-rotor reactor, a supergravity reactor, a separation unit, and a regeneration unit.

[0024] According to the apparatus of the present invention, preferably, the structure of the supergravity reactor includes, but is not limited to, a stator-rotor reactor, a rotating packed bed, a baffled bed, etc.

[0025] According to the apparatus of the present invention, preferably, the separation unit is a buffer tank; and the regeneration unit is a regeneration tower.

[0026] This invention reduces the formation of grease by controlling the reaction temperature and contact time, thereby minimizing the condensation and dissolution of unsaturated hydrocarbons in the amine solution. Simultaneously, it utilizes the strong self-cleaning capability of the stator-rotor reactor to reduce the impact of grease on the deacidification gas unit. Compared to existing technologies, the method of this invention reduces grease formation and, due to the strong shearing effect, is less prone to reactor blockage, thus enhancing the stability of the ethylene cracking gas deacidification gas unit.

[0027] The beneficial effects of this invention include:

[0028] 1) Compared with the existing ethylene cracking gas deacidification unit, the method of the present invention greatly reduces the contact time between the gas and liquid phases and inhibits the dissolution of butadiene and heavy dienes in amine liquid, thereby inhibiting the formation of butter from the source.

[0029] 2) The method of the present invention inhibits the adhesion and accumulation of grease on the internal components through strong shearing action, effectively preventing grease from clogging the reactor, thereby achieving stable operation of the deacidification gas unit;

[0030] 3) Compared with existing ethylene cracking gas deacidification units, the method of the present invention has a simple process, requires less equipment space, and has lower energy consumption. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the butter reduction device and process in the ethylene cracking gas deacidification unit of a preferred embodiment of the present invention.

[0032] Explanation of reference numerals in the attached figures:

[0033] 1. Stator-rotor reactor;

[0034] 2. Hypergravity reactor;

[0035] 3. Separation unit;

[0036] 4. Regeneration unit;

[0037] 5. First heat exchanger;

[0038] 6. Second heat exchanger. Detailed Implementation

[0039] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments, further clarifies the invention. Those skilled in the art should understand that the specific descriptions below are illustrative rather than restrictive, and should not be construed as limiting the scope of protection of the present invention.

[0040] All numerical specifications in this invention (e.g., temperature, time, concentration, and weight, including ranges for each) are generally approximate values ​​that may be changed (+) or (-) in increments of 0.1 or 1.0. All numerical specifications are to be understood as being preceded by the term "about".

[0041] The present invention provides a preferred embodiment, such as... Figure 1 As shown, the ethylene cracking gas deacidification unit butter reduction device includes: stator-rotor reactor 1, supergravity reactor 2, separation unit 3 and regeneration unit 4; it also includes a first heat exchanger 5 and a second heat exchanger 6.

[0042] After heat exchange in the first heat exchanger 5, the ethylene cracked gas and lean amine liquid enter the reactor through the gas phase inlet of the stator-rotor reactor 1, while the lean amine liquid enters the reactor through the liquid phase inlet. The defoamer enters the reactor through the auxiliary inlet arranged on the stator. The ethylene cracked gas, amine liquid, and defoamer mix inside the stator and rotor. Under the action of both, the amine liquid and defoamer are sheared and torn into tiny liquid filaments, droplets, and liquid films, possessing a huge interphase mass transfer specific surface area and a rapid surface renewal rate, thus efficiently removing acidic gas from the ethylene cracked gas. After the acidic gas is removed, the gas and liquid phases of the stator-rotor reactor 1 exit the reactor, respectively.

[0043] During the process of removing acidic gases, hydrocarbons inevitably enter the amine solution. To prevent dissolved hydrocarbons from forming butter during the thermal regeneration of the amine solution, the rich amine solution entering the regeneration unit 4 is oil-washed to remove dissolved hydrocarbons. The rich amine solution leaving the stator-rotor reactor 1 and the wash oil enter the reactor through the liquid phase inlet of the high gravity reactor 2 for oil washing: the rich amine solution and the wash oil are mixed inside the rotor, and the high-speed rotating rotor breaks the oil and water phases into tiny droplets. Through continuous aggregation and dispersion, the mass transfer process of hydrocarbons from the aqueous phase to the oil phase is completed; the hydrocarbons dissolved in the amine solution are extracted into the wash oil, and then the rich amine solution and the wash oil enter the separation unit 3 (preferably a buffer tank) for separation; the wash oil aggregates into the oil phase and leaves from the top of the separation unit 3; the rich amine solution aggregates into the aqueous phase and leaves from the bottom of the separation unit 3.

[0044] After the separated rich amine liquid is heat-recovered by exchanging heat with the regenerated lean liquid, it enters the regeneration unit 4 (e.g., regeneration tower) for regeneration. The regenerated lean amine liquid and the oil-washed rich amine liquid are heat-exchanged by the second heat exchanger 6 and by the ethylene cracking gas through the first heat exchanger 5. After the lean amine liquid is adjusted to a suitable temperature, it enters the stator-rotor reactor 1 for recycling.

[0045] In this reactor, the liquid phase moves from the inside to the outside under the drive of the rotor, and the residence time of the gas and liquid phases in chamber 1 of the stator-rotor reactor is ≤1s. Because the contact time is very short, the mass transfer process of hydrocarbons into the amine liquid is effectively suppressed, reducing hydrocarbon dissolution and decreasing the total amount of grease generated at the source. The radial distance between the stator ring and rotor ring of the stator-rotor reactor is 1–10 mm, preferably 1–5 mm; the linear velocity of the outermost rotor is 20–40 m / s, preferably 30–40 m / s. With a small distance between the stator ring and rotor ring and a relatively high velocity, a strong shear force is generated between them, preventing the generated grease from depositing on the reactor's internal components; for grease already adhering to the internal components, the strong shear force forces it to detach. Therefore, this greatly enhances the stability of the reactor and ensures the efficiency of acid gas removal.

[0046] Example 1

[0047] This embodiment uses Figure 1 The equipment and process flow deacidify ethylene cracking gas and reduce the volume of butter, including the following processes:

[0048] Ethylene cracking gas containing acidic gas and 40°C lean amine liquid (20wt% MDEA solution) heated to 40°C by the first heat exchanger 5 enter the stator and rotor of the stator-rotor reactor 1 through the gas phase and liquid phase inlets, respectively. Methyl silicone oil enters the reactor through the additive inlet arranged on the stator. The gap between adjacent stator rings and rotor rings is 5mm, and the linear velocity of the outermost rotor is 40m / s. After the acidic gas is removed, the gas phase and liquid phase leave the reactor from the gas phase and liquid phase outlets of the stator-rotor reactor 1, respectively.

[0049] The rich amine liquid leaving the stator-rotor reactor 1 and the cracked gasoline enter the reactor through the liquid phase inlet of the supergravity reactor 2 for oil washing: the volume ratio of cracked gasoline to rich amine liquid is 1:10; after oil washing, the rich amine liquid separated by the separation unit 3 (buffer tank) enters the regeneration unit 4 (regeneration tower) for regeneration, and the lean amine liquid obtained after regeneration is cooled by heat exchange and then enters the stator-rotor reactor 1 for recycling.

[0050] After the system reached stability, the oil content in the liquid phase was sampled and analyzed at the liquid phase outlet of the stator-rotor reactor, and found to be 136 mg / L. When the stator-rotor reactor 1 was disassembled, no grease was found adhering to the internal components.

[0051] Example 2

[0052] This embodiment uses Figure 1 The equipment and process flow deacidify ethylene cracking gas and reduce the volume of butter, including the following processes:

[0053] Ethylene cracked gas containing acidic gas, heated to 38°C by the first heat exchanger 5, and lean amine liquid (20wt% MDEA solution) at 39°C, enter the stator and rotor of the stator-rotor reactor 1 through the gas phase and liquid phase inlets, respectively. The high-carbon alcohol defoamer enters the reactor through the additive inlet arranged on the stator. The gap between adjacent stator rings and rotor rings is 9mm, and the linear velocity of the outermost rotor is 20m / s. After the acidic gas is removed, the gas phase and liquid phase leave the reactor from the gas phase and liquid phase outlets of the stator-rotor reactor 1, respectively.

[0054] The rich amine liquid leaving the stator-rotor reactor 1 and the cracked gasoline enter the reactor through the liquid phase inlet of the supergravity reactor 2 for oil washing: the volume ratio of cracked gasoline to rich amine liquid is 1:20; after oil washing, the rich amine liquid separated by the separation unit 3 (buffer tank) enters the regeneration unit 4 (regeneration tower) for regeneration, and the lean amine liquid obtained after regeneration is cooled by heat exchange and then enters the stator-rotor reactor 1 for recycling.

[0055] After the system reached stability, the oil content in the liquid phase was sampled and analyzed at the liquid phase outlet of stator-rotor reactor 1, and found to be 347 mg / L. When stator-rotor reactor 1 was disassembled, no grease was found adhering to the internal components.

[0056] Comparative Example 1

[0057] This comparative example uses the following process to remove acid from ethylene cracking gas:

[0058] Ethylene cracking gas containing acidic gas at 40°C and lean amine liquid (20wt% MDEA solution) at 35°C enter the stator and rotor of stator-rotor reactor 1 through the gas phase and liquid phase inlets, respectively; methyl silicone oil enters the reactor through the additive inlet arranged on the stator; the gap between adjacent stator rings and rotor rings is 5mm, and the linear velocity of the outermost rotor is 40m / s; after the acidic gas is removed, the gas phase and liquid phase leave the reactor from the gas phase and liquid phase outlets of stator-rotor reactor 1, respectively.

[0059] The rich amine liquid leaving the stator-rotor reactor 1 and the cracked gasoline enter the reactor through the liquid phase inlet of the supergravity reactor 2 for oil washing: the volume ratio of cracked gasoline to rich amine liquid is 1:10; after oil washing, the rich amine liquid separated by the separation unit 3 (buffer tank) enters the regeneration unit 4 (regeneration tower) for regeneration, and the lean amine liquid obtained after regeneration is cooled by heat exchange and then enters the stator-rotor reactor 1 for recycling.

[0060] After the system reached stability, the oil content in the liquid phase was sampled and analyzed at the liquid outlet of stator-rotor reactor 1, and found to be 1320 mg / L. When the stator-rotor reactor 1 was disassembled, no grease was found adhering to the internal components.

[0061] A comparison of Example 1 and Comparative Example 1 shows that when the temperature difference between the ethylene cracked gas and the lean amine liquid entering the stator-rotor reactor 1 is too large, heavy olefins in the ethylene cracked gas are prone to condense and precipitate, forming butter, which increases the butter content in the liquid phase. Therefore, the temperatures of the gas and liquid phases entering the stator-rotor reactor should be controlled to reduce the formation of butter.

[0062] Comparative Example 2

[0063] This comparative example uses the following process to remove acid from ethylene cracking gas:

[0064] Ethylene cracking gas containing acidic gas and 40°C lean amine liquid (20wt% MDEA solution) heated to 40°C by the first heat exchanger 5 enter the stator and rotor of the stator-rotor reactor 1 through the gas phase and liquid phase inlets, respectively. Methyl silicone oil enters the reactor through the additive inlet arranged on the stator. The gap between adjacent stator rings and rotor rings is 5mm, and the linear velocity of the outermost rotor is 40m / s. After the acidic gas is removed, the gas phase and liquid phase leave the reactor from the gas phase and liquid phase outlets of the stator-rotor reactor 1, respectively.

[0065] The rich amine solution leaving the stator-rotor reactor 1 enters the regeneration unit 4 (regeneration tower) for regeneration. The lean amine solution obtained after regeneration is cooled by heat exchange and then enters the stator-rotor reactor 1 for recycling.

[0066] After the system reached stability, the oil content in the liquid phase was sampled and analyzed at the liquid outlet of stator-rotor reactor 1, and found to be 2862 mg / L. When the stator-rotor reactor 1 was disassembled, no grease was found adhering to the internal components.

[0067] As can be seen from the comparison between Example 1 and Comparative Example 2, the unwashed amine-rich liquid contains a certain amount of butadiene and heavy dienes. If it directly enters the regeneration unit for thermal regeneration, the high temperature during the regeneration process will promote the polymerization of unsaturated olefins such as butadiene, generating butter and increasing the butter content in the liquid phase. Therefore, the amine-rich liquid should be washed with oil before entering the regeneration unit to reduce the generation of butter.

[0068] Comparative Example 3

[0069] This comparative example uses Figure 1 The equipment and process flow deacidify ethylene cracking gas and reduce the volume of butter, including the following processes:

[0070] Ethylene cracking gas containing acidic gas at 40℃ and lean amine liquid (20wt% MDEA solution) at 40℃ enter the stator and rotor of stator-rotor reactor 1 through the gas phase and liquid phase inlets, respectively; methyl silicone oil enters the reactor through the additive inlet arranged on the stator; the gap between adjacent stator rings and rotor rings is 20mm, and the linear velocity of the outermost rotor is 40m / s; after the acidic gas is removed, the gas phase and liquid phase leave the reactor from the gas phase and liquid phase outlets of stator-rotor reactor 1, respectively.

[0071] The amine-rich liquid leaving the stator-rotor reactor 1 and the cracked gasoline enter the reactor through the liquid phase inlet of the supergravity reactor 2 for oil washing: the volume ratio of cracked gasoline to amine-rich liquid is 1:10; after oil washing, the amine-rich liquid separated by the separation unit 3 enters the regeneration unit 4 (regeneration tower) for regeneration, and the lean amine liquid obtained after regeneration is cooled by heat exchange and then enters the stator-rotor reactor 1 for recycling.

[0072] After the system reached stability, the oil content in the liquid phase was sampled and analyzed at the liquid phase outlet of the stator-rotor reactor, and found to be 324 mg / L. When the stator-rotor reactor 1 was disassembled, a small amount of grease was found adhering to the internal components.

[0073] As can be seen from the comparison between Example 1 and Comparative Example 3, when the gap between adjacent stator rings and rotor rings is too large, it cannot provide sufficient shear force to prevent the generated grease from adhering to the internal components.

[0074] Comparative Example 4

[0075] This comparative example uses Figure 1 The equipment and process flow deacidify ethylene cracking gas and reduce the volume of butter, including the following processes:

[0076] Ethylene cracking gas containing acidic gas at 40℃ and lean amine liquid (20wt% MDEA solution) at 40℃ enter the stator and rotor of stator-rotor reactor 1 through the gas phase and liquid phase inlets, respectively; methyl silicone oil enters the reactor through the additive inlet arranged on the stator; the gap between adjacent stator rings and rotor rings is 5mm, and the linear velocity of the outermost rotor is 10m / s; after the acidic gas is removed, the gas phase and liquid phase leave the reactor from the gas phase and liquid phase outlets of stator-rotor reactor 1, respectively.

[0077] The rich amine liquid leaving the stator-rotor reactor 1 and the cracked gasoline enter the reactor through the liquid phase inlet of the supergravity reactor 2 for oil washing: the volume ratio of cracked gasoline to rich amine liquid is 1:10; after oil washing, the rich amine liquid separated by the separation unit 3 (buffer tank) enters the regeneration unit 4 (regeneration tower) for regeneration, and the lean amine liquid obtained after regeneration is cooled by heat exchange and then enters the stator-rotor reactor 1 for recycling.

[0078] After the system reached stability, the oil content in the liquid phase was sampled and analyzed at the liquid phase outlet of the stator-rotor reactor, and found to be 467 mg / L. When the stator-rotor reactor 1 was disassembled, a small amount of grease was found adhering to the internal components.

[0079] A comparison of Example 1 and Comparative Example 4 shows that a low outermost rotor linear velocity means a low rotor speed. A lower speed cannot provide sufficient shear force to prevent the generated grease from adhering to the internal components. Simultaneously, a lower speed increases the residence time of the liquid in the reactor, increasing the solubility of hydrocarbons in the liquid phase.

[0080] Comparative Example 5

[0081] This comparative example uses an amine scrubbing tower to remove acid from ethylene cracked gas, including the following processes:

[0082] Ethylene cracking gas containing acidic gas at 40℃ and lean amine liquid (20wt% MDEA solution) at 40℃ enter the amine washing tower through the gas phase and liquid phase inlets, respectively; methyl silicone oil enters the amine washing tower after being pre-mixed with the amine liquid; after the removal of acidic gas is completed, it leaves from the gas phase and liquid phase outlets of the amine washing tower, respectively.

[0083] The rich amine liquid leaving the amine washing tower and the cracked gasoline enter the reactor through the liquid phase inlet of the supergravity reactor for oil washing: the volume ratio of cracked gasoline to rich amine liquid is 1:10; after oil washing, the rich amine liquid separated by separation unit 3 (buffer tank) enters regeneration unit 4 (regeneration tower) for regeneration, and the lean amine liquid obtained after regeneration is cooled by heat exchange and then enters the amine washing tower for recycling.

[0084] After the system stabilized, samples were taken at the liquid phase outlet of the amine washing tower and the oil content in the liquid phase was analyzed to be 969 mg / L. When the amine washing tower was disassembled, a lot of grease was found adhering to the internal components.

[0085] As can be seen from the comparison between Example 1 and Comparative Example 5, when an amine scrubbing tower is used as the site for removing acidic gases, a large amount of unsaturated hydrocarbons dissolve in the amine solution due to the long residence time in the tower. Even with an oil washing process before the regeneration unit, the unsaturated hydrocarbons dissolved in the amine solution cannot be completely washed away, resulting in the generation of a large amount of grease in the regeneration unit. Some of the generated grease enters the amine scrubbing tower along with the lean solution. Due to the weak self-cleaning ability of the amine scrubbing tower, the grease brought in by the lean solution accumulates on the trays or packing, clogging the amine scrubbing tower.

[0086] As can be seen from the examples and comparative examples, the method provided by the present invention can reduce the generation of grease in the deacidification gas unit and inhibit the adhesion of grease to the internal components of the deacidification gas unit.

[0087] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A method for reducing the amount of butter in an ethylene cracking gas deacidification unit, characterized in that, This method for reducing butter volume includes the following steps: Ethylene cracking gas, lean amine liquid, and defoamer are fed into a stator-rotor reactor. The gas phase and liquid phase come into countercurrent contact inside the stator and rotor. After the acid gas is removed, the gas phase and liquid phase are output from the stator-rotor reactor, respectively. The output liquid phase is a rich amine solution. The rich amine solution and the wash oil are introduced into the supergravity reactor for oil washing at a volume ratio of 1:10 to 20. After that, the rich amine solution and the wash oil enter the separation unit for separation. The separated amine-rich solution is regenerated into amine-lean solution, which is then recycled into the stator-rotor reactor. The ethylene cracked gas enters the reactor from the gas phase inlet of the stator-rotor reactor after heat exchange. After heat exchange, the temperature of the ethylene cracked gas increases, but does not exceed 45°C. The lean amine liquid, after being cooled by heat exchange, enters the reactor through the liquid phase inlet of the stator-rotor reactor. After cooling, the temperature difference between the liquid and the ethylene cracking gas entering the stator-rotor reactor is ≤1℃.

2. The method for reducing butter volume according to claim 1, characterized in that, The residence time of the ethylene cracking gas, lean amine solution, and defoamer in the stator-rotor reactor is ≤1s.

3. The method for reducing butter volume according to claim 1, characterized in that, The radial distance between the stator ring and the rotor ring of the stator-rotor reactor is 1 mm to 10 mm; the linear velocity of the outermost rotor is 20 m / s to 40 m / s.

4. The method for reducing butter volume according to claim 1, characterized in that, The radial distance between the stator ring and the rotor ring of the stator-rotor reactor is 1mm to 5mm; the linear velocity of the outermost rotor is 30m / s to 40m / s.

5. The method for reducing butter volume according to claim 1, characterized in that, The defoamer enters the reactor through an additive inlet located on the stator of the stator-rotor reactor.

6. The method for reducing butter volume according to claim 1, characterized in that, The defoamer is selected from one or more of the following: high molecular weight alcohols and silicones.

7. The method for reducing butter volume according to claim 1, characterized in that, The wash oil is cracked gasoline or hydrogenated gasoline.

8. The method for reducing butter volume according to claim 1, characterized in that, The rich amine liquid separated by the separation unit exchanges heat with the regenerated lean amine liquid and then enters the regeneration unit for regeneration. The regenerated lean amine liquid exchanges heat with the rich amine liquid separated by the separation unit and the ethylene cracking gas in sequence, and then adjusts the lean amine liquid to a suitable temperature before entering the stator-rotor reactor for recycling.

9. A butter reduction device for an ethylene cracking gas deacidification unit, characterized in that, The device is used to implement the butter reduction method according to any one of claims 1-8, comprising: a stator-rotor reactor, a supergravity reactor, a separation unit, and a regeneration unit.

10. The butter reduction device for the ethylene cracking gas deacidification unit according to claim 9, characterized in that, The structure of the supergravity reactor can be a stator-rotor reactor, a rotating packed bed, or a baffled bed.

11. The butter reduction device for the ethylene cracking gas deacidification unit according to claim 9, characterized in that, The separation unit is a buffer tank; the regeneration unit is a regeneration tower.

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