A continuously dehydrated ethanol synthesis reaction system

Abstract

This utility model discloses a continuously dehydrated ethanol synthesis reaction system, comprising: a gas-liquid reactor, wherein the lower part of the gas-liquid reactor is provided with a first air inlet for inputting fresh raw materials, and the upper part is provided with a first liquid inlet for inputting fresh raw materials; a first air outlet at the top of the gas-liquid reactor is connected to a second air inlet at the lower end of the gas-liquid reactor via a pipeline to form a gas-phase external circulation loop; a first liquid outlet at the bottom of the gas-liquid reactor is connected to the second liquid inlet at the upper part of the gas-liquid reactor via a dehydration device to form a liquid-phase external circulation loop; wherein the dehydration device includes at least two parallel adsorption columns, which allows the dehydration device to alternately perform water adsorption and water desorption operations. By using at least two parallel adsorption columns to alternately adsorb and desorb, continuous production operation can be achieved, and the adsorption / desorption cycle can be dynamically adjusted according to the reactor water outlet rate to optimize adsorption efficiency and improve reaction efficiency.

Description

Technical Field

[0001] This invention relates to the field of ethanol synthesis technology, and in particular to an ethanol synthesis reaction system capable of continuous dehydration. Background Technology

[0002] Currently, in the one-step synthesis of ethanol from methanol, CO2, and H2, the methanol conversion rate and ethanol selectivity are very low. As the reaction continues, even with a sufficient amount of substrate, methanol will not reach 100% conversion. Moisture is the key reason why the reaction cannot continue. Existing CO2 hydrogenation to ethanol technologies do not mention water removal technology. At the same time, the biggest problem with gas-liquid reactors is how to enhance gas-liquid mass transfer. Current stirred reactors, Venturi spray towers, and bubble reactors all have relatively low gas-liquid mass transfer efficiency. Utility Model Content

[0003] Based on the above-mentioned technical problems, this utility model provides an ethanol synthesis reaction system that can continuously dehydrate, which can achieve efficient gas-liquid mass transfer and greatly improve reaction efficiency.

[0004] To achieve the above objectives, the technical solution adopted by this utility model is: a continuously dehydrated ethanol synthesis reaction system, comprising: a gas-liquid reactor, wherein the lower part of the gas-liquid reactor is provided with a first air inlet for inputting fresh raw materials, and the upper part is provided with a first liquid inlet for inputting fresh raw materials; the air outlet at the top of the gas-liquid reactor is connected to the second air inlet at the lower end of the gas-liquid reactor via a pipeline to form a gas-phase external circulation loop; the liquid outlet at the bottom of the gas-liquid reactor is connected to the second liquid inlet at the upper part of the gas-liquid reactor via a dehydration device to form a liquid-phase external circulation loop; wherein the dehydration device includes at least two parallel adsorption columns, which enable the dehydration device to alternately perform water adsorption and water desorption operations.

[0005] Furthermore, the gas-liquid reactor is provided with multiple mass transfer units. Each mass transfer unit includes a first tray and a second tray arranged vertically. The first tray is a hollow frustum with openings on the top and bottom, and the second tray is a cone with an opening on the bottom. The bottom opening of the first tray is opposite to the top opening of the second tray.

[0006] Furthermore, the conical surface of the second tray is provided with multiple through holes for liquid to pass through.

[0007] Furthermore, the adsorption column is a 3A molecular sieve adsorption column.

[0008] Furthermore, the adsorption column is provided in two parts.

[0009] Furthermore, each of the adsorption columns is equipped with a valve at the bottom and a liquid outlet at the top.

[0010] Furthermore, each of the adsorption columns is provided with a gas purging inlet at the bottom and a gas outlet at the top.

[0011] Furthermore, the gas-liquid reactor is a tower reactor.

[0012] Furthermore, a compressor is provided on the external gas phase circulation loop.

[0013] Furthermore, a circulation pump is provided on the pipeline connecting the liquid outlet at the bottom of the gas-liquid reactor to the dehydration device.

[0014] The beneficial effects of this invention are as follows: By using two or more parallel adsorption columns to form a dehydration device for alternating adsorption and desorption, continuous production operation can be achieved. At the same time, the adsorption / desorption cycle can be dynamically adjusted according to the reactor effluent rate to optimize adsorption efficiency, thereby improving reaction efficiency and significantly increasing single-pass conversion rate. In addition, the use of perforated frustum and conical trays filled in the gas-liquid reactor achieves efficient mass transfer and reaction, increases the gas-liquid contact area, accelerates interface renewal, improves reaction rate, and reduces energy consumption by gravity-driven liquid flow. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of the continuously dehydrated ethanol synthesis reaction system in this embodiment of the present invention;

[0016] Figure 2 This is a schematic diagram of the mass transfer unit structure in an embodiment of the present invention;

[0017] Figure reference numerals: 1-Gas-Liquid Reactor, A-Mass Transfer Unit, 10-First Tray, 11-Second Tray, 100-Bottom, 110-Through Hole; 12-First Gas Inlet, 13-First Liquid Inlet, 14-Gas Outlet, 15-Second Gas Inlet, 16-Liquid Outlet, 17-Second Liquid Inlet, 2-Compressor, 3-Dehydration Device, 30-First Adsorption Column, 31-Second Adsorption Column, 300-First Gas Purge Inlet, 301-First Gas Outlet, 302-First Valve, 303-First Liquid Outlet, 310-Second Gas Purge Inlet, 311-Second Gas Outlet, 312-Second Valve, 313-Second Liquid Outlet, 4-Circulation Pump Detailed Implementation

[0018] To make the above-mentioned objectives, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0019] This application provides a continuously dehydrated ethanol synthesis reaction system, overcoming the shortcomings of traditional gas-liquid exchange systems, such as small contact area and low mass transfer efficiency. It should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0020] Example:

[0021] Reference Figure 1 The continuously dehydrated ethanol synthesis reaction system includes a gas-liquid reactor 1. The lower part of the gas-liquid reactor 1 is provided with a first air inlet 12 for inputting fresh raw materials, and the upper part is provided with a first liquid inlet 13 for inputting fresh raw materials. The top gas outlet 14 of the gas-liquid reactor 1 is connected to the lower gas inlet 15 of the gas-liquid reactor 1 via a pipeline to form a gas phase external circulation loop. The bottom liquid outlet 16 of the gas-liquid reactor 1 is connected to the upper liquid inlet 17 of the gas-liquid reactor 1 via a dehydration device 3 to form a liquid phase external circulation loop. The dehydration device 3 includes at least two parallel adsorption columns, which allows the dehydration device 3 to alternately perform water adsorption and water desorption operations.

[0022] The gas-liquid reactor 1 provided in this embodiment has gas and liquid external circulation loops. Gas enters from the first gas inlet 12 at the bottom and flows back from the top. Liquid enters from the first liquid inlet 13 at the top and flows back from the bottom. The circulation is repeated. The liquid loop keeps the liquid continuously flowing out of the tray inside the gas-liquid reactor 1. Gas is always distributed in the reactor, which enhances gas-liquid exchange and solves the disadvantage of small contact area in traditional gas-liquid exchange.

[0023] like Figure 2 As shown, the gas-liquid reactor 1 is equipped with multiple mass transfer units A. Each mass transfer unit A includes a first tray 10 and a second tray 11 arranged vertically. The first tray 10 is a hollow frustum with openings at both the top and bottom, while the second tray 11 is a cone with an opening at the bottom. The openings of the first tray 10 and the top of the second tray 11 are opposite to each other. The conical surface of the second tray 11 has multiple through holes 110. The liquid phase components in the reaction flow directionally into the top of the cone 11 of the lower tray through the bottom opening 100 of the first tray 10 and out through the through holes 110. Due to the different designs of the upper and lower trays, the liquid exiting from the bottom opening 100 of the first tray 10 flows precisely to the tip of the second tray 11. The liquid flows down the conical wall and into the lower tray through the through holes 110, circulating repeatedly. The gas is uniformly dispersed in the reactor, and the liquid is in uniform contact with the gas in the form of droplets. The two-layer tray structure design, combined with directional flow, ensures that the liquid is evenly distributed between the trays and fully in contact with the liquid, avoiding local liquid stagnation. At the same time, the external circulation reflux prolongs the liquid phase residence time, enhances gas-liquid mass transfer, and can carry impurities and solid particles away from the reaction zone, reducing the risk of blockage.

[0024] Continue to refer to Figure 1 As a preferred embodiment, a compressor 2 is provided on the gas phase external circulation loop, which is used to return the unreacted components in the gas phase recovered from the top of the gas-liquid reactor 1 back to the lower end of the gas-liquid reactor 1 for further reaction; the dehydration device 3 includes at least two parallel adsorption columns, and the number can be set according to actual needs. In this embodiment, as a preferred embodiment, the dehydration device 3 includes two adsorption columns. Since the ethanol synthesis method in this embodiment uses methanol as the substrate, the selection of the dehydration molecular sieve is considered to remove the water generated during the experiment without adsorbing the reactant methanol. Therefore, 3A molecular sieve is selected and the adsorption column is filled for dehydration.

[0025] As a preferred embodiment, each adsorption column is equipped with a valve at the bottom and a liquid outlet at the top. Furthermore, each adsorption column can be equipped with a gas purging inlet at the bottom and a gas outlet at the top.

[0026] As a preferred approach, the gas-liquid reactor 1 is a tower reactor.

[0027] As a preferred embodiment, a circulation pump 4 is provided on the pipeline connecting the liquid outlet 16 at the bottom of the gas-liquid reactor 1 to the dehydration device 3. The circulation pump 4 can circulate the liquid phase components recovered at the bottom of the gas-liquid reactor 1 to the adsorption column of the dehydration device 3 for dehydration.

[0028] The overall process of the preferred continuously dehydrated ethanol synthesis reaction system described above is as follows: Fresh raw material gas enters the gas-liquid reactor 1 through the first inlet 12, and fresh raw material liquid enters the gas-liquid reactor 1 through the first liquid inlet 13. After the gas and liquid react, the remaining gas is released from the top outlet 14, passes through the compressor 2, and re-enters the gas-liquid reactor 1 through the second inlet 15 located at the bottom of the gas-liquid reactor 1. The liquid phase after the liquid and gas reacts flows out from the bottom outlet 16 of the gas-liquid reactor 1, passes through the circulation pump 4, and enters the dehydration device 3. During the water adsorption process... The first adsorption column 30 and the second adsorption column 31 are controlled by the first valve 302 and the second valve 312, and adsorption and desorption are performed alternately. During desorption, hot CO2 gas enters the first adsorption column 30 and the second adsorption column 31 loaded with 3A molecular sieve from the first gas purge inlet 300 and the second gas purge inlet 310, respectively. After the water is purged away, it is discharged from the first gas outlet 301 and the second gas outlet 311. The liquid after adsorbing water continues to return to the gas-liquid reactor 1 from the second liquid inlet 17 at the top of the gas-liquid reactor 1 for gas-liquid contact circulation reaction.

[0029] Specifically, both the first adsorption column 30 and the second adsorption column 31 are filled with a fixed amount of 3A molecular sieve. Desorption and adsorption occur simultaneously. First, the first adsorption column 30 performs adsorption alone. The second valve 312, the second liquid outlet 313, the first gas purge inlet 300, and the first gas outlet 301 are closed. The first valve 302 and the first liquid outlet 303 are opened. The liquid that has reacted in the gas-liquid reactor 1 enters the first adsorption column 30 through the first valve 302. After the adsorption in the first adsorption column 30 is completed, the liquid returns to the gas-liquid reactor 1 through the first liquid outlet 303. At this time, after the adsorption in the first adsorption column 30 is completed, desorption begins. The first valve 302 and the first liquid outlet 303 are closed. 03. The second gas purging inlet 310 and the second gas outlet 311 are opened. The second valve 312 and the second liquid outlet 313 are opened. The first gas purging inlet 300 and the first gas outlet 301 are opened. CO2 gas enters the first adsorption column 30 through the first gas purging inlet 300 to purge the molecular sieve at 200°C. The purged gas is discharged through the first gas outlet 301. After the moisture is purged, the molecular sieve is cooled with cold air. At the same time as purging, the liquid in the gas-liquid reactor 1 continues to flow into the second adsorption column 31 through the second valve 312 for adsorption. The adsorbed liquid continues to flow into the gas-liquid reactor 1 through the second liquid outlet 313 to continue the reaction. The two adsorption columns operate alternately at the same time.

[0030] The dual-column parallel design enables continuous operation: while one column is adsorbing, the other column is desorbing or regenerating, ensuring stable system operation. The selective adsorption of water by the molecular sieve can deeply dehydrate the ethanol, achieving industrial-grade purity. It also breaks through the limitations of reaction equilibrium, allowing the reaction to proceed in the forward direction and improving the conversion rate. Water can deactivate the catalyst, and the removal of water by the adsorption column can extend the catalyst's lifespan.

[0031] The following specific experiments will verify the continuously dehydrated ethanol synthesis reaction system of this embodiment:

[0032] Example for comparison:

[0033] Methanol and catalyst were fed into a tower reactor at a molar ratio of 1:5, and CO2 and H2 were fed into the tower reactor at a molar ratio of 1:3. The total liquid feed was 400 g, the total pressure was 8 MPa, and the tower reactor temperature was 170 °C. The molecular sieve adsorption column was not filled with 3A molecular sieve and no water was absorbed. The experiment lasted for 5 hours. The moisture content after the reaction was measured to be 6.8%, the methanol conversion rate was 33%, and the ethanol selectivity was 17%.

[0034] Experimental Example 1:

[0035] Methanol and catalyst were fed into a tower reactor at a molar ratio of 1:5, and CO2 and H2 were fed into the tower reactor at a molar ratio of 1:3. The total liquid feed was 400g, the total pressure was 8MPa, and the tower reactor temperature was 170℃. Each of the two molecular sieve adsorption columns was filled with 100g of 3A molecular sieve. The experiment was carried out for 5 hours. The moisture content of the reaction was measured to decrease from 6.8% to 1.5%, the methanol conversion rate reached 60%, and the ethanol selectivity was 49%.

[0036] After the molecular sieve adsorption column has adsorbed all the water, it is purged and regenerated by passing CO2 gas at 200℃ for 3 minutes, and then purged by passing CO2 gas at room temperature for 2 minutes to cool down the 3A molecular sieve.

[0037] Experimental Example 2:

[0038] Methanol and catalyst were fed into a tower reactor at a molar ratio of 1:5, and CO2 and H2 were fed into the tower reactor at a molar ratio of 1:3. The total liquid feed was 400g, the total pressure was 8MPa, and the tower reactor temperature was 170℃. Each of the two molecular sieve adsorption columns was filled with 200g of 3A molecular sieve. The experiment was carried out for 5 hours. The moisture content of the reaction was measured to decrease from 6.8% to 0.4% during the reaction. The methanol conversion rate reached 92%, and the ethanol selectivity reached 65%.

[0039] After the molecular sieve adsorption column has adsorbed all the water, it is purged and regenerated by passing CO2 gas at 200℃ for 3 minutes, and then purged by passing CO2 gas at room temperature for 2 minutes to cool down the 3A molecular sieve.

[0040] A table comparison is made based on the above experiments:

[0041]

[0042]

[0043] As can be seen from the table above, under the same experimental conditions, the more 3A molecular sieves are filled into the adsorption column within a certain range, the less water is present during the reaction, the higher the methanol conversion rate, and the higher the ethanol selectivity. This achieves the breakthrough of the reaction equilibrium limitation, enabling the reaction to proceed in the forward direction and improving the conversion rate.

[0044] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0045] The embodiments described above merely illustrate the implementation of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A continuously dewaterable ethanol synthesis reaction system, characterized by, include: A gas-liquid reactor (1) is provided with a first air inlet (12) for inputting fresh raw materials at the lower part and a first liquid inlet (13) for inputting fresh raw materials at the upper part. The air outlet (14) provided at the top of the gas-liquid reactor (1) is connected to the second air inlet (15) provided at the lower end of the gas-liquid reactor (1) via a pipeline to form a gas phase external circulation loop. The liquid outlet (16) provided at the bottom of the gas-liquid reactor (1) is connected to the second liquid inlet (17) at the upper part of the gas-liquid reactor (1) via a dehydration device (3) to form a liquid phase external circulation loop. The dehydration device (3) includes at least two adsorption columns connected in parallel, which allows the dehydration device (3) to alternately perform water adsorption and water desorption operations.

2. The continuously dewaterable ethanol synthesis reaction system of claim 1, wherein: The gas-liquid reactor is provided with multiple mass transfer units (A). Each mass transfer unit (A) includes a first tray (10) and a second tray (11) arranged vertically. The first tray (10) is a hollow frustum with openings on the top and bottom, and the second tray (11) is a cone with an opening on the bottom. The bottom opening (100) of the first tray (10) is opposite to the top of the second tray (11).

3. The continuously dewaterable ethanol synthesis reaction system of claim 2, wherein: The conical surface of the second tray (11) is provided with a plurality of through holes (110) for liquid to pass through.

4. The continuously dewaterable ethanol synthesis reaction system of claim 1, wherein: The adsorption column is a 3A molecular sieve adsorption column.

5. The continuously dewaterable ethanol synthesis reaction system of claim 1, wherein: The adsorption column is provided in two parts.

6. The continuously dewaterable ethanol synthesis reaction system of claim 1, wherein: Each of the adsorption columns is equipped with a valve at the bottom and a liquid outlet at the top.

7. The continuously dewaterable ethanol synthesis reaction system of claim 6, wherein: Each of the adsorption columns is provided with a gas purging inlet at the bottom and a gas outlet at the top.

8. The continuously dewaterable ethanol synthesis reaction system of claim 1, wherein: The gas-liquid reactor (1) is a tower reactor.

9. The continuously dewaterable ethanol synthesis reaction system of claim 1, wherein: A compressor (2) is provided on the external gas phase circulation loop.

10. The continuously dewaterable ethanol synthesis reaction system of claim 1, wherein: A circulation pump (4) is provided on the pipeline connecting the liquid outlet (16) at the bottom of the gas-liquid reactor to the dehydration device (3).

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