Alkaline lignin decomposition reactor and decomposition method

Abstract

The application discloses a kind of alkali lignin decomposition reactor and decomposition method, decomposition reactor includes reactor shell, electrode, power supply and stirring device, reactor shell has the solution reaction zone and plasma generation area of communication;The electrode the electrode is located in the plasma generation area, the positive pole and the negative pole of the electrode can produce uniform electric field to produce active species with discharge gas;Power supply is connected with electrode, for providing power supply for electrode, stirring device in decomposition process, can the lignin solution of solution reaction be stirred, so that lignin is fully contacted with the active species and reacts.Decomposition method uses the alkali lignin decomposition reactor of the present application to process lignin, can decompose lignin, at the same time, in degradation process, can be discharged uniformly, so as to reduce the damage to reactor shell electrode.

Description

Technical Field

[0001] This invention relates to the field of alkali lignin treatment technology, specifically to an alkali lignin decomposition reactor and decomposition method. Background Technology

[0002] Alkali lignin, as the only natural renewable aromatic polymer containing a benzene ring, has attracted much attention due to its numerous aromatic structures. It is an ideal raw material for the sustainable production of aromatic compounds and fuels, playing a significant role in the high-value utilization of biomass and is widely used in everyday technologies. However, due to its complex chemical structure, large molecular weight, and diverse types, previous depolymerization techniques have been quite demanding, thus limiting the utilization of alkali lignin to some extent.

[0003] In recent years, traditional methods for lignin degradation have mainly included biodegradation, physical degradation, and chemical degradation. Biodegradation offers the advantage of relatively mild conditions, but factors such as enzyme activity limit its application to specific pathways. Physical degradation primarily involves adjusting microwave and ultrasonic parameters to regulate the reaction, which can reduce energy costs to some extent, but large-scale application is currently not feasible. Chemical degradation is the most widely used method, boasting high conversion rates and good selectivity, but its complexity stems from expensive catalysts and demanding reaction conditions.

[0004] Plasma methods generate substances such as OH- by introducing a catalyst or using external energy. 1 O2 and O3, among other oxidizing reactive oxygen species (ROS), depolymerize polymers. Through continuous research, the dielectric barrier discharge plasma (DBD) technique in plasma methods has been found to generate strong electric fields, a large number of high-energy electrons, and ultraviolet light, and can also produce reactive oxygen species (such as OH-, etc.). 1 Chemical reactions such as those involving O2 and O3 can break bonds, open rings, and even mineralize organic molecules to produce carbon dioxide and water. Theoretically, these physicochemical effects can break the monomer bonds in alkali lignin to obtain products that retain the benzene ring structure, or even break the aromatic rings in its structure into smaller molecule products, thereby effectively improving the utilization of alkali lignin.

[0005] Currently, the dielectric barrier discharge (DBD) technology applied to the degradation of alkali lignin is mainly a single dielectric barrier discharge technology. Rabia-Muazam et al. utilized ozone generated in the shell of a microbubble reactor to activate the depolymerization of lignin into valuable compounds, overcoming the drawbacks of complex product mixing. Characterization results showed that the aromatic rings and aliphatic side chains of the recovered lignin underwent partial oxidation. A significant advantage of this reactor shell is the minimal ozone loss during the plasma transfer from the generation zone to the reaction zone. The glass microspheres in the microreactor shell can increase the dielectric constant within the reactor shell; however, the discharge process is relatively uneven, and the high-voltage electrodes are easily corroded. Zhou et al. combined DBD with the Fenton system to degrade lignin in an ethanol medium. The high-energy environment generated by localized discharge on the ethanol surface is highly suitable for lignin depolymerization, and the products are rich in aromatic hydrocarbons, dicarboxylic acids, and their derivatives. Two reaction devices were designed: one with direct grounding and one with indirect grounding of the ethanol. The advantage is that the experimental instrument can be directly converted into a reaction device, and a water-cooling device is introduced at the neck to mitigate the temperature rise during discharge. However, the disadvantages are uneven discharge and the tendency for corrosion of the high-voltage electrodes in both direct and indirect grounding solutions. Summary of the Invention

[0006] In view of the shortcomings of the existing technology, the technical problem to be solved by the present invention is to provide an alkali lignin decomposition reactor and decomposition method, which can effectively decompose lignin. At the same time, during the decomposition process, it can discharge evenly, thereby reducing damage to the reactor shell electrodes.

[0007] To achieve the above objectives, the present invention provides the following technical solution: an alkali lignin decomposition reactor and decomposition method, comprising:

[0008] The reactor shell has a connected solution reaction zone and a plasma generation zone;

[0009] An electrode is located within the plasma generation region. The positive and negative electrodes of the electrode can generate a uniform electric field to interact with the discharge gas and produce active species.

[0010] A power source, connected to the electrodes, is used to provide power to the electrodes.

[0011] The stirring device can stir the lignin solution in the reaction zone during the decomposition process, thereby allowing the alkali lignin in the lignin solution to come into contact with and react with the active species.

[0012] Furthermore, it also includes a water cooling device for cooling the reactor shell and maintaining a constant temperature inside the reactor shell.

[0013] Furthermore, it also includes an oscilloscope connected to the power supply for converting electrical signals into visual images.

[0014] Furthermore, it also includes a transformer connected to the power supply for stabilizing and regulating the voltage of the power supply.

[0015] Furthermore, the stirring device is a magnetically stirred reactor shell, and the reactor shell is located within the magnetically stirred reactor shell.

[0016] Furthermore, the electrode comprises a plurality of solid copper rods, each of which is covered with an insulating protective sleeve, and the positive and negative terminals of adjacent solid copper rods are staggered.

[0017] Furthermore, the reactor shell is provided with an inlet pipe and an outlet pipe communicating with the solution reaction zone, and the reactor shell is provided with an inlet pipe and an outlet pipe communicating with the plasma generation zone.

[0018] A method for decomposing alkali lignin, using the alkali lignin decomposition reactor described above, includes:

[0019] A solution of alkali lignin of a certain concentration is placed into the reaction zone and the stirring device is started.

[0020] Discharge gas is introduced into the reactor shell;

[0021] Connect the electrodes to the power supply and ground them; turn on the power supply to discharge and generate a uniform electric field, generating active species inside the reactor shell, which can react with lignin in the solution.

[0022] Maintain the power supply's discharge frequency at 8.11 kHz, adjust the voltage, and control the reaction time to complete the degradation.

[0023] Furthermore, during the treatment process, the temperature inside the reactor shell is kept constant.

[0024] Furthermore, during the treatment process, the concentration of alkali lignin used was 2.0 g / L, the voltage of the power supply was 11.5 kV, and the reaction time was controlled to be 25 min.

[0025] The beneficial effects of this invention are:

[0026] In the above-mentioned alkali lignin decomposition reactor and decomposition method, a lignin solution of a certain concentration is placed in the solution reaction zone 110, and then a discharge gas such as air is introduced into the plasma generation zone 120. Next, the electrode 200 is connected to the power supply 300 and grounded. After adjusting the input adjustment voltage and the discharge frequency, the stirring device 400 is turned on, and the discharge reaction can be carried out to carry out the decomposition reaction. During the process, the stirring device 400 stirs the lignin solution, so that the lignin in the lignin solution can fully contact and react with the active species. The main product is aromatic compounds, until the reaction is completed.

[0027] Using this decomposer, under the action of the stirring device, the alkali lignin in the lignin solution can fully contact and react with the active species. The decomposition of lignin by the stirring device in conjunction with plasma treatment can greatly improve the decomposition rate, thereby improving the utilization of lignin. At the same time, since the positive and negative electrodes can generate a uniform electric field, the discharge inside the reactor shell can be uniform, thereby reducing damage to the electrodes of the reactor shell. Attached Figure Description

[0028] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the specific embodiments will be briefly described below. In all the drawings, the elements or parts are not necessarily drawn to scale.

[0029] Figure 1 This is a schematic diagram of an alkali lignin decomposition reactor provided in an embodiment of the present invention;

[0030] Figure 2 for Figure 1 The alkali lignin decomposition reactor shown illustrates the effects of different conditions on the lignin decomposition effect (A: effect of output voltage on decomposition effect; B: effect of reaction time on decomposition effect; C: effect of lignin dosage on decomposition effect; D: discharge images under different output voltages).

[0031] Figure 3 for Figure 1 The infrared absorption spectra of the decomposition products obtained at different reaction times after lignin decomposition in the alkali lignin decomposition reactor are shown.

[0032] Figure 4 for Figure 1 The UV spectrum of the decomposition products after lignin decomposition in the alkali lignin decomposition reactor is shown.

[0033] Figure 5 for Figure 1 The ratio of alkali lignin decomposition products at different reaction times after lignin decomposition in the alkali lignin decomposition reactor shown.

[0034] Figure 6 for Figure 1 The diagram shows a method for lignin decomposition using an alkali lignin decomposition reactor.

[0035] Figure label:

[0036] 100. Reactor shell; 110. Solution reaction zone; 120. Plasma discharge zone; 200. Electrode; 300. Power supply; 400. Stirring device; 500. Oscilloscope; 600. Transformer. Detailed Implementation

[0037] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0038] Please see Figures 1 to 6 The alkali lignin decomposition reactor provided by the present invention includes a reactor shell 100, an electrode 200, a power supply 300, and a stirring device 400.

[0039] Please see Figure 1 Specifically, the reactor shell 100 has a connected solution reaction zone 110 and a plasma generation zone 120. The solution reaction zone 110 is used to store the lignin solution. During use, a discharge gas is introduced into the plasma generation zone 120. The discharge gas flow diffuses in the plasma generation zone 120 in a certain pattern, which can affect the diffusion of active species within the solution reaction zone 110. In a specific implementation, the discharge gas can preferably be air.

[0040] Electrode 200 is located within plasma generation region 120, and its positive and negative electrodes generate a uniform electric field to interact with the discharge gas and produce active species. Power supply 300 is connected to electrode 200 to provide power to electrode 200. In specific implementations, power supply 300 can be a CTP-2000K low-temperature plasma power supply.

[0041] In use, the positive electrode is connected to the power supply 300, and the negative electrode can be grounded. When the power supply 300 is turned on, a large number of high-energy electrons, hydroxyl radicals, ozone and other active species are generated in the plasma generation zone 120. The active species can react with the lignin solution in the solution reaction zone 110, causing the aromatic benzene ring in the lignin to open and break bonds and degrade into small molecule products, thereby achieving the purpose of decomposing alkali lignin.

[0042] During the decomposition process, the stirring device 400 can stir the lignin solution in the solution reaction zone 110, thereby allowing the alkali lignin in the lignin solution to fully contact and react with the active species.

[0043] In use, a lignin solution of a certain concentration is placed in the solution reaction zone 110, and then a discharge gas such as air is introduced into the plasma generation zone 120. Next, the electrode 200 is connected to the power supply 300 and grounded. After adjusting the input voltage and the discharge frequency, the stirring device 400 is turned on, and the discharge reaction can be carried out to decompose the lignin solution. During the process, the stirring device 400 stirs the lignin solution to ensure that the lignin in the lignin solution comes into full contact with the active species and reacts. The main product is aromatic compounds, until the reaction is complete.

[0044] The concentration of alkali lignin was calculated using the standard curve method. The decomposition rate (%) was used to characterize the lignin-decomposing ability of DBD under different discharge reaction conditions. The decomposition rate was calculated using Formula 1-1:

[0045] ……………………(1-1)

[0046] In the formula, C0 is the initial concentration of the alkali lignin solution (mg / L); Ce is the concentration of the alkali lignin solution after the reaction (mg / L).

[0047] Using this degrader, under the action of the stirring device 400, the lignin in the lignin solution can fully contact and react with the active species. The lignin decomposition is carried out by the stirring device 400 in conjunction with plasma, which greatly improves the biochemical degradation rate of lignin. At the same time, since the positive and negative electrodes of the electrode 200 can generate a uniform electric field, the discharge inside the reactor shell 100 can be uniform, thereby reducing damage to the electrodes 200 of the reactor shell 100.

[0048] The results showed that, under the conditions of a discharge frequency of 8.11 kHz, a reaction time of 25 min, an alkali lignin dosage of 2.0 g / L, and an output voltage of 11.5 kV, the lignin decomposition rate of this decomposition reactor was 23.1%. This device had the strongest decomposition capacity, and the decomposition products were mainly aromatic compounds, among which 2,2'-methylenebis(6-tert-butyl-4-methylphenol) had the highest selectivity of 86.78%.

[0049] In a preferred embodiment, the decomposition reactor shell 100 further includes a water cooling device (not shown in the figure), which is used to cool the reactor shell 100 and maintain a constant temperature inside the reactor shell 100. In a more specific implementation, the reactor shell 100 can be placed in the cooling liquid of the water cooling device to cool the reactor shell 100 and achieve a constant temperature inside the reactor shell 100. The water cooling device can also be a spray method to cool the reactor shell 100 and maintain a constant temperature inside the reactor shell 100.

[0050] As another preferred embodiment, the decomposition reactor shell 100 may also include a transformer 600. The transformer 600 is connected to the power supply 300 and is used to stabilize the power supply 300 and adjust the voltage, thereby ensuring the smooth progress of the degradation reaction. Simultaneously, an oscilloscope 500 may also be included, connected to the power supply 300, for converting electrical signals into visual images to facilitate voltage adjustment. In a specific implementation, the oscilloscope 500 may be a Rigol MSO5204 oscilloscope from the prior art.

[0051] In practical implementation, the stirring device 400 can be placed inside the solution reaction zone 110 to directly stir the lignin solution. Alternatively, the stirring device 400 can be placed outside the reactor shell 100, with the reactor shell 100 mounted on the stirring device 400, allowing the lignin solution to be stirred externally.

[0052] In this embodiment, the stirring device 400 is a magnetically stirred reactor shell. The magnetically stirred reactor shell 100 can be a commonly used magnetic stirrer in the prior art. This can greatly save on degradation costs. In other embodiments, the stirring device 400 uses an external vibration device or a rocking device to vibrate or rock the reactor shell 100, causing the liquid inside the degrader to oscillate, which can also achieve a stirring effect.

[0053] In this embodiment, the electrode 200 includes a plurality of solid copper rods, each of which is covered with an insulating protective sleeve, and the positive and negative terminals of adjacent solid copper rods are staggered. The purpose of this design is to enable uniform discharge throughout the entire electrode.

[0054] The solid copper rod serves as an electrical conductor, while the insulating protective sleeve serves as an insulating element. The insulating protective sleeve can be made of quartz tube.

[0055] Furthermore, in practical implementation, an inlet pipe and an outlet pipe communicating with the plasma discharge zone can be provided on the upper part of the reactor shell 100 to facilitate the introduction of discharge gas. In addition, a lignin solution can be provided on the reactor shell 100, and after the reaction is completed, the reacted liquid is released through the liquid outlet pipe 140.

[0056] Please see Figure 6 The present invention also provides a lignin decomposition treatment method, which uses the above-mentioned alkali lignin decomposition reactor for decomposition treatment, and includes the following steps:

[0057] S110. Place a certain concentration of alkali lignin solution into the solution reaction zone 110 and start the stirring device 400.

[0058] Specifically, stirring can be done by directly stirring the liquid or by vibrating the reactor shell 100.

[0059] S120. Introduce discharge gas into the reactor shell 100.

[0060] Specifically, the gas can be ordinary air, or other gases containing nitrogen and oxygen.

[0061] S130. Connect electrode 200 to power supply 300 and ground it; turn on power supply 300 and generate a uniform electric field. Active species are generated in reactor shell 110 and react with alkali lignin.

[0062] Specifically, during use, the positive electrode is connected to power supply 300, and the negative electrode can be grounded. When power supply 300 is turned on, a uniform magnetic field is generated, causing a large number of high-energy electrons, hydroxyl radicals, ozone, and other active species to form in the plasma generation region 120. These active species can react with alkali lignin in the lignin solution, causing the aromatic benzene ring in the alkali lignin to open and break bonds, degrading into small molecule products.

[0063] S140. Maintain the power supply's discharge frequency at 8.11kHz, adjust the voltage, and control the reaction time until degradation is complete.

[0064] In a preferred embodiment, the temperature inside the reactor shell 100 can be kept constant during the processing, thereby stabilizing the reaction. This temperature control can be achieved by cooling the surface of the reactor shell 100 with a water-cooling device, thus maintaining the temperature inside the reactor shell 100 within a certain range.

[0065] Furthermore, during the treatment process, the concentration of alkali lignin was 2.0 g / L, the voltage of the power supply was 11.5 kV, and the reaction time was controlled to 25 min, resulting in a selectivity of up to 86.78% for aromatic compounds.

[0066] The following describes the use of this reactor for alkali lignin treatment, employing multiple implementation methods and a reactor shell, to investigate the effects of different reaction times, concentrations, and input voltages on the degradation effect:

[0067] Example 1: The effect of discharge voltage on decomposition rate:

[0068] Under the conditions of a reaction time of 10 min and a reaction volume of 1.0 g / L alkali lignin solution, the decomposition rate of lignin by the reactor shell was investigated at output voltages of 8.5, 10.0, 11.5, and 13.0 kV to screen for the optimal discharge voltage. Each experiment was repeated three times, and the results are as follows: Figure 2 As shown in Figure A.

[0069] Depend on Figure 2 As shown in A, the decomposition rate of lignin in the system changes accordingly with the output voltage. When the output voltage reaches 11.5 kV, the decomposition rate of lignin in the reaction system reaches 6.8%. Further increases in output voltage will decrease the decomposition rate. This is because, with the increase in output voltage, both the discharge intensity and uniformity increase (e.g., ...). Figure 2(D) At voltages of 8.5 kV and 10.0 kV, the decomposition rate showed no significant change. At these voltages, the electro-optic light was purplish in color, with weak intensity, large gaps between the discharge filaments, and unstable discharge, resulting in a low decomposition rate. When the voltage increased to 11.5 kV, the electro-optic light intensity was stronger, and there were almost no gaps between the discharge filaments, indicating a stable and uniform discharge. At this point, more active substances were obtained, leading to an increased decomposition rate of lignin. While increasing the voltage improved both the discharge intensity and uniformity to some extent, further increases would raise the system temperature, affecting the stability of the active substances and hindering the reaction. Therefore, the voltage with the highest decomposition rate, 11.5 kV, was selected as the optimal discharge voltage.

[0070] Example 2: The effect of reaction time on decomposition effect:

[0071] At an output voltage of 11.5 kV, 100 mL of a 1.0 g / L alkali lignin solution was added to the reactor. The decomposition rate of lignin by this decomposer was investigated at time intervals of 5, 10, 15, 20, 25, and 30 min. The optimal reaction time was determined, and each experiment was repeated three times. The results are as follows: Figure 2 As shown in B.

[0072] Depend on Figure 4 It was observed that the decomposition rate of alkali lignin gradually increased from 1.7% at 5 minutes to 20.8% at 25 minutes with increasing discharge reaction time. This is attributed to the increased production of active substances in the system with increasing discharge time, and the increased likelihood of contact between these active substances and lignin, leading to a more complete reaction. When the reaction time was further increased to 30 minutes, the decomposition rate did not increase significantly, and combined analysis with infrared spectroscopy and mass spectrometry revealed that the product rapidly transformed from aromatic compounds to aliphatic compounds. Therefore, 25 minutes is the optimal reaction time for obtaining a greater amount of aromatic ring compounds.

[0073] Example 3: Effect of reaction concentration on decomposition efficiency:

[0074] 100 mL of alkali lignin solutions of different concentrations were added to the reactor. Under the conditions of a reaction time of 25 min and a discharge voltage of 11.5 kV, the decomposition rate of lignin by the reactor shell was investigated at dosages of 0.5, 1.0, 1.5, 2.0, and 2.5 g / L. The optimal dosage was screened. Each experiment was repeated three times. The results are as follows: Figure 2 As shown in C.

[0075] When the amount of lignin was 0.5 and 1.0 g / L, the decomposition rate of the system did not change significantly, remaining around 21.0%. When the amount of lignin was gradually increased from 1.0 g / L to 2.0 g / L, the decomposition rate gradually increased to 23.1%. This is because as the amount of lignin increased, the utilization rate of the active substance increased, leading to a gradual increase in the lignin decomposition rate. When the amount of lignin was further increased to 2.5 g / L, the reaction concentration was too high. In the same amount of time, the increased probability of collisions between the active substance and lignin molecules caused the released heat to rise, leading to a decrease in the stability of the active substance produced in the reactor shell 100. This deactivation of the active substance reduced the amount of active substance that could effectively participate in the reaction, resulting in a significant decrease in the lignin decomposition rate. Furthermore, the active substance produced in the same amount of time was consumed, and some lignin did not react fully, further reducing the lignin decomposition rate. Therefore, a concentration of 2.0 g / L was selected as the optimal reaction concentration for alkali lignin.

[0076] Please see Figure 3 , Figure 3 The images show the infrared absorption spectra of the decomposition products obtained at different reaction times. Compared with the original alkali lignin sample, the reacted sample showed a higher absorption rate at 3450 cm⁻¹. -1 The increased intensity of the OH stretching vibration near the reaction site indicates an increase in hydroxyl groups after the reaction. This is due to the breakage of ether bonds between monomers during lignin decomposition, generating hydroxyl groups. At 2930 cm⁻¹ -1 The intensity of CH stretching vibration increased compared to the original sample, which may be due to the elongation of side chains in lignin.

[0077] In addition, 1630cm -1 The structure remains unchanged before and after the reaction, and still exhibits a stable aromatic skeleton structure after discharge treatment. Meanwhile, at 1380 cm⁻¹... -1 The slightly enhanced CO peak indicates that some lignin monomers may have undergone condensation during discharge. The 1190 cm⁻¹ value associated with the guaiac matrix unit... -1 1050cm -1 The CH deformation vibration is enhanced after treatment, which means that the guaiacol group is generated by the demethylation of the syringyl group. This is also consistent with the reduced CO bond in the methoxy group (1380 cm⁻¹) characteristic peak of the syringyl group after the reaction. -1 The functional group regions and fingerprint regions of the curves in the figure are macroscopically similar, indicating that the lignin is partially decomposed into monomers or small molecule products containing aromatic ring structures, and residual lignin still exists.

[0078] Observe the changes in the ultraviolet absorption spectrum during the discharge of alkali lignin. The results are as follows: Figure 4As shown, the absorbance at the 280 nm UV characteristic absorption peak of lignin is a characteristic absorption caused by electronic transitions in the benzene ring structure of lignin. With increasing reaction time, the absorbance at this point decreases, indicating that the conjugated structure in the sample is disrupted, and some aromatic substances are oxidized by the active substances, resulting in ring breakage and ring opening, thus leading to a decrease in absorbance. This demonstrates that this reactor is effective for the decomposition of alkali lignin.

[0079] GC-MS was used to analyze the reaction products of lignin. Using the self-made reactor shell as the reaction apparatus, the decomposition products of alkali lignin were mainly aromatic compounds, long-chain alkanes, and aliphatic oxygen-containing compounds. Figure 5 This chart compares the proportions of aromatic and aliphatic compounds in the decomposition products at different time points. From 0-25 min, the decomposition products are mainly aromatic compounds, with a selectivity of 86.78% for 2,2'-methylenebis-(4-methyl-6-tert-butylphenol) at 25 min. At 30 min, the decomposition products are mainly long-chain alkanes and aliphatic oxygen-containing compounds, with only a small amount of aromatic compounds. The reason for the large amount of long-chain alkanes, long-chain acids, esters, and other aliphatic organic compounds generated during the long reaction is the production of more ozone. The longer ozone reaction time causes the aromatic ring structure of lignin to open, leading to a decrease in the content of aromatic compounds. At shorter reaction times, an electrophilic reaction occurs at the junction between ozone and alkali lignin monomers, causing the chemical bonds to break. Therefore, the shorter reaction time results in a higher content of monomeric aromatic substances in the decomposition products. Therefore, when using a reaction device to decompose alkali lignin, the type and content of decomposition products can be controlled by changing conditions such as reaction time. Thus, in the above embodiment, it can be concluded that when the concentration of alkali lignin used is 2.0 g / L, the voltage of the power supply is 11.5 kV, and the reaction time is controlled at 25 min, the content of aromatic compounds in the decomposition products is the highest.

[0080] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A method for decomposing alkali lignin, characterized in that, An alkali lignin decomposition reactor is used, the alkali lignin decomposition reactor comprising: The reactor shell has a connected solution reaction zone and a plasma generation zone; An electrode is located within the plasma generation region. The positive and negative electrodes of the electrode can generate a uniform electric field to interact with the discharge gas and produce active species. A power source, connected to the electrodes, is used to provide power to the electrodes. The stirring device can stir the lignin solution in the reaction zone during the decomposition process, thereby allowing the alkali lignin in the lignin solution to come into contact with and react with the active species. The method includes: A solution of alkali lignin of a certain concentration is placed into the reaction zone and the stirring device is started. Discharge gas is introduced into the reactor shell; Connect the electrodes to the power supply and ground them; turn on the power supply to discharge and generate a uniform electric field, generating active species inside the reactor shell, which can react with lignin in the solution. Maintain the power supply's discharge frequency at 8.11 kHz, adjust the voltage, and control the reaction time to complete the degradation.

2. The alkali lignin decomposition method according to claim 1, characterized in that, It also includes a water cooling device for cooling the reactor shell and keeping the temperature inside the reactor shell constant.

3. The alkali lignin decomposition method according to claim 1, characterized in that, It also includes an oscilloscope, which is connected to the power supply and is used to convert electrical signals into visual images.

4. The alkali lignin decomposition method according to claim 1, characterized in that, It also includes a transformer, which is connected to the power source and is used to stabilize the voltage of the power source and regulate the voltage magnitude.

5. The alkali lignin decomposition method according to claim 1, characterized in that, The stirring device is a magnetically stirred reactor shell, and the reactor shell is located within the magnetically stirred reactor shell.

6. The method for decomposing alkali lignin according to claim 1, characterized in that, The electrode comprises a plurality of solid copper rods, each of which is covered with an insulating protective sleeve, and the positive and negative terminals of adjacent solid copper rods are staggered.

7. The method for decomposing alkali lignin according to claim 1, characterized in that, The reactor shell is provided with an inlet pipe and an outlet pipe that communicate with the solution reaction zone, and the reactor shell is provided with an inlet pipe and an outlet pipe that communicate with the plasma generation zone.

8. The method for decomposing alkali lignin according to claim 1, characterized in that, During the process, the temperature inside the reactor shell is kept constant.

9. The method for decomposing alkali lignin according to claim 8, characterized in that, During the treatment process, the concentration of alkali lignin used was 2.0 g / L, the voltage of the power supply was 11.5 kV, and the reaction time was controlled at 25 min.

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