A method for in-situ synthesis of H2O2 based on low-temperature plasma driven hydrogen production

Abstract

The present invention belongs to the technical field of hydrogen peroxide preparation, and proposes a method for in-situ synthesis of H2O2 based on low-temperature plasma driven hydrogen production. The in-situ synthesis method of H2O2 uses water vapor as a hydrogen source, utilizes plasma to drive the water gas reaction to produce hydrogen, and reacts with oxygen to generate H2O2 in situ, thereby realizing the one-step generation of H2O2 from CO, O2 and water vapor in a plasma reactor. Compared with the anthraquinone method, the reaction conditions of the present invention are mild and the process flow is simple. Compared with the direct generation of H2O2 from hydrogen and oxygen, the present invention effectively avoids the explosion risk caused by the contact between hydrogen and oxygen, and at the same time realizes the resource utilization and high value of CO in industrial waste gas. In addition, the present invention can greatly improve the space-time yield of H2O2, reaching 2700 g H2O2 L ‑1 h ‑1 The above has achieved exponential growth compared to existing technologies and made significant technological progress.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen peroxide preparation, and in particular to an in-situ synthesis method of H2O2 based on low-temperature plasma driven hydrogen production. Background Art

[0002] Hydrogen peroxide (H2O2) is a green and pollution-free strong oxidant. There is a large demand for hydrogen peroxide in the industrial field. At present, 95% of hydrogen peroxide in industry is produced by the anthraquinone method. For example, the Chinese invention patent application with publication number CN117682483A discloses a preparation method for producing hydrogen peroxide by the anthraquinone method, but this method has problems such as long process, high energy consumption, and serious environmental pollution. For this reason, direct synthesis of hydrogen peroxide has attracted much attention as a more atomic efficient and greener synthesis route. The Chinese invention patent with publication number CN100575248C directly synthesizes hydrogen peroxide in a hood tower reactor. In the presence of a precious metal catalyst, a reaction medium containing a halide and a strong acid is used to synthesize a hydrogen peroxide solution from H2, O2, and N2. The Chinese invention patent application with publication number CN117342528A proposes a method for directly synthesizing a hydrogen peroxide aqueous solution from hydrogen and oxygen, using carbon dioxide as a diluent gas, and then introducing hydrogen and oxygen to directly synthesize hydrogen peroxide reaction, which reduces the risk of combustion and explosion caused by direct contact between hydrogen and oxygen to a certain extent. However, this method must be carried out in an alcohol, inorganic acid or bromide medium, and the separation cost of the product hydrogen peroxide is high. In addition, the direct synthesis of H2O2 from hydrogen and oxygen cannot meet the requirements of industrial production due to factors such as reaction mass transfer and reaction rate control steps.

[0003] In summary, there is an urgent need to develop a safe, efficient and environmentally friendly method for producing and preparing H2O2. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention proposes a low-cost, green and safe method for preparing hydrogen peroxide, which is based on low-temperature plasma driven hydrogen production and in-situ synthesis of H2O2. It overcomes the problems of high energy consumption, serious secondary environmental pollution, high risk factor caused by explosive hydrogen-oxygen mixed gas, etc. in the existing H2O2 preparation technology, solves the pollution problem caused by CO emissions, and produces H2O2 urgently needed by industry in-situ, which has significant environmental and economic benefits.

[0005] The technical solution of the present invention is as follows:

[0006] The invention discloses an in-situ synthesis method of H2O2 based on low-temperature plasma driven hydrogen production, which uses CO, O2 and water vapor as raw materials to synthesize H2O2 in situ in a plasma reactor.

[0007] Furthermore, the H2O2 in-situ synthesis method is completed at normal temperature and pressure.

[0008] Furthermore, a water vapor generator is used to generate water vapor, and the water vapor is precisely controlled by a peristaltic pump, and CO, O2, and water vapor are first mixed and then introduced into a plasma reactor. The specific input energy Q and the gas residence time J in the plasma reactor satisfy: ,in, , the unit of Q is kJ / l, and the unit of J is s.

[0009] Furthermore, the plasma reactor is a corona discharge plasma reactor, a glow discharge plasma reactor, a jet plasma reactor or a dielectric barrier discharge reactor; the dielectric barrier discharge reactor is a flat dielectric barrier discharge reactor, a cylindrical dielectric barrier discharge reactor, a coaxial dielectric barrier discharge reactor or a multi-needle dielectric barrier discharge reactor, and the dielectric thickness is 1 mm.

[0010] Furthermore, the high voltage electrode of the cylindrical dielectric barrier discharge reactor is made of copper rod, aluminum rod or tungsten rod, the grounding electrode is made of stainless steel, nickel, carbon material or salt solution, and the dielectric material is made of quartz glass, ceramic or polymer material.

[0011] Furthermore, the in situ synthesized H2O2 is collected by condensation.

[0012] Furthermore, the treatment CO concentration window is 1-10%.

[0013] Furthermore, the molar ratio of CO, O2 and water vapor is 1:[0-1):1, 1:0.6:[0-1) or [0-1):0.6:1.

[0014] Furthermore, the molar ratio of CO, O2 and water vapor is 1:0.6:1.

[0015] Furthermore, the specific energy input of the plasma reactor is 3-15 kJ / l and the gas residence time is 0.01-0.04 s.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The present invention proposes an in-situ synthesis method of H2O2 based on low-temperature plasma driven hydrogen production. Compared with the traditional H2O2 preparation method using the anthraquinone method, it can achieve in-situ one-step synthesis of H2O2. It has the characteristics of simple preparation process and rapid reaction, and is particularly suitable for actual industrial production links.

[0018] 2. The present invention proposes an in-situ synthesis method of H2O2 based on low-temperature plasma driven hydrogen production, constructs a reaction system with CO, O2 and water vapor, and greatly improves the space-time yield of H2O2 by designing the ratio of raw materials and optimizing the introduction method. Compared with the existing technology, it has achieved significant technical progress.

[0019] 3. The present invention proposes an in-situ synthesis method of H2O2 based on low-temperature plasma driven hydrogen production, and uniquely designs the reaction in the plasma reactor. The specific input energy Q and gas residence time J in the plasma reactor satisfy: ,in, When the molar ratio of CO, O2 and water vapor is controlled to be 1:0.6:1, the space-time yield of H2O2 can reach 2700 g H2O2L -1 h -1 above.

[0020] 4. The present invention proposes an in-situ synthesis method of H2O2 based on low-temperature plasma driven hydrogen production, using industrial waste gas CO as raw material, effectively consuming a large amount of CO emissions from industries such as coal chemical industry, while reducing environmental pollution caused by CO, obtaining high-value by-product H2O2, realizing the resource utilization and high value of industrial waste gas, and providing new ideas for energy conversion.

[0021] 5. The present invention proposes an in-situ synthesis method of H2O2 based on low-temperature plasma driven hydrogen production. Compared with the direct synthesis of H2O2 by low-temperature plasma H2 / O2, it has no explosion risk, high time-space yield, and higher safety, environmental protection, and economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. The features and advantages of the present invention can be more clearly understood by referring to the drawings. The drawings are schematic and should not be understood as limiting the present invention in any way. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 This is a graph showing the effect of the O2 ratio on the gaseous product distribution and H2O2 hourly production in Example 1.

[0024] Figure 2 This is a graph showing the effect of H2O content on the distribution of gaseous products and the hourly production of H2O2 in Example 2.

[0025] Figure 3 This is a graph showing the effect of CO content on the distribution of gaseous products and the hourly production of H2O2 in Example 3.

[0026] Figure 4 This is a graph showing the effect of the input energy ratio on the gaseous product distribution and H2O2 hourly production in Example 4.

[0027] Figure 5 This is a graph showing the effect of residence time on the distribution of gaseous products and the hourly production of H2O2 in Example 5.

[0028] Figure 6 This is a long-term stability test diagram in Example 6.

[0029] Figure 7 It is a comparison diagram of the reaction system of the present invention in Example 8 and other reaction systems in the prior art. DETAILED DESCRIPTION

[0030] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0031] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0032] Example 1

[0033] The specific input energy in the plasma reactor was set to 9 kJ / l, the gas residence time was 0.02 s, and the molar ratio of CO, O2, and water vapor was in the range of 1:[0-1):1. The effect of O2 injection on the gaseous product distribution and the hourly production of H2O2 was analyzed. The results are shown in Figure 1 As shown in the figure, with the increase of O2 intake, the CO conversion rate gradually increases. When the molar ratio of CO, O2, and water vapor is 1:0.6:1, O2 is completely converted, and the hourly production of H2O2 reaches the highest and no longer increases with the increase of O2 intake. At this time, the H2O2 production is 2.74 mmol / h, the CO conversion rate is 75.29%, the CO2 generation rate is 74.83%, and the space-time yield is 2757.06 g H2O2 / L·h.

[0034] Example 2

[0035] The specific input energy in the plasma reactor was set to 9 kJ / l, the gas residence time was 0.02 s, and the molar ratio of CO, O2, and water vapor was in the range of 1:0.6:[0-1). The effect of H2O input on the gaseous product distribution and H2O2 hourly production was analyzed. The results are shown in Figure 2As shown in the figure, with the increase of H2O input, the CO conversion rate and H2O2 hourly production both showed a trend of first increasing and then decreasing. When the proportion of H2O input exceeded CO, it was not conducive to the reaction, and the CO conversion rate and H2O2 hourly production both decreased. When the molar ratio of CO, O2, and water vapor was 1:0.6:1, the CO conversion rate was 75.29%, the O2 conversion rate was 83.27%, the CO2 generation rate was 74.83%, the H2O2 production was 2.74 mmol / h, and the space-time yield was 2757.06 g H2O2 / L·h.

[0036] Example 3

[0037] The specific input energy in the plasma reactor was set to 9 kJ / l, the gas residence time was 0.02 s, and the molar ratio of CO, O2, and water vapor was in the range of [0-1]:0.6:1. The effect of CO input on the gaseous product distribution and the hourly production of H2O2 was analyzed. The results are shown in Figure 3 As shown in the figure, the hourly production of H2O2 is the highest when the CO feed accounts for 10%. With the continuous increase of CO feed, the conversion rates of CO and O2 continue to increase, but the hourly production of H2O2 does not continue to increase. Therefore, the optimal reaction feed ratio of CO, O2, and water vapor is 1:0.6:1, the CO conversion rate is 75.29%, the O2 conversion rate is 83.27%, the CO2 generation rate is 74.83%, the H2O2 production is 2.74 mmol / h, and the space-time yield is 2757.06 g H2O2 / L·h.

[0038] Example 4

[0039] The gas residence time in the plasma reactor was set to 0.02 s, the molar ratio of CO, O2, and water vapor was set to 1:0.6:1, and the specific input energy (SEI) was adjusted to 3-15 kJ / l. Figure 4 As shown in the figure, the specific input energy has a significant effect on the in-situ reaction. The conversion rates of CO and O2 increase with the increase of specific input energy (SEI), but too high specific input energy SEI is not conducive to the generation of H2O2. When the specific input energy (SEI) is 9 kJ / l, the hourly production of H2O2 is the highest. At this time, the CO conversion rate is 75.29%, the O2 conversion rate is 83.27%, the CO2 generation rate is 74.83%, the H2O2 production is 2.74 mmol / h, and the space-time yield is 2757.06 g H2O2 / L·h.

[0040] Example 5

[0041] The specific input energy in the plasma reactor was set to 9 kJ / l, and the molar ratio of CO, O2, and water vapor was set to 1:0.6:1. The experiment analyzed the effect of the gas residence time in the plasma reactor on the distribution of gaseous products and the hourly production of H2O2. Figure 5 As shown, the gas residence time has little effect on the conversion rate of CO and O2, and has a slight effect on the hourly production of H2O2. The H2O2 production is optimal when the residence time is 0.02 s. Therefore, the optimal reaction conditions for the in-situ synthesis method of H2O2 based on low-temperature plasma driven hydrogen production proposed in the present invention are: the molar ratio of feed ratio CO:O2:H2O is 1:0.6:1, the specific input energy (SEI) is 9 kJ / l, and the gas residence time is 0.02 s. At this time, the CO conversion rate is 75.29%, the O2 conversion rate is 83.27%, the CO2 generation rate is 74.83%, the H2O2 production is 2.74 mmol / h, and the space-time yield is 2757.06 g H2O2 / L·h.

[0042] Example 6

[0043] The optimal reaction conditions were used and the reaction was continued for 1-5 hours to test the long-term stability of the H2O2 in-situ synthesis method of the present invention. Figure 6 As shown in the figure, the reaction system can maintain a good H2O2 hourly production even after a test time of 5 h, and has excellent stability.

[0044] Example 7

[0045] The present invention further innovates the way CO, O2, and water vapor are introduced into the reaction system, and proposes a reaction method in which water vapor is generated by a water vapor generator, the water vapor is precisely controlled by a peristaltic pump, and CO, O2, and water vapor are first mixed and then introduced into the plasma reactor. This reaction method can further improve the time-space yield of H2O2. Experimental verification was carried out as follows:

[0046] (1) CO, O2, and water vapor are introduced into the bubbling tank, and the water vapor is brought into the plasma reactor. At this time, the space-time yield of H2O2 is 932.42 g H2O2 / L·h.

[0047] (2) A water vapor generator and a peristaltic pump were used to precisely control the amount of water injected. CO, O2, and water vapor were injected into the plasma reactor separately, and the space-time yield of H2O2 was 1900 g H2O2 / L·h.

[0048] (3) A steam generator and a peristaltic pump are used to precisely control the amount of water injected. CO, O2, and water vapor are first mixed and then introduced into the plasma reactor. The space-time yield of H2O2 is 2748.08 g H2O2 / L·h.

[0049] Example 8

[0050] Under the same experimental conditions, the reaction system of the present invention was compared with other reaction systems in the prior art. The results are as follows Figure 7 As shown. Among them, [8] H2O2 is directly synthesized by plasma reaction of H2 / O2, with a time-space yield of 42.97, [9] H2O2 is synthesized by argon, water molecules and H2 / O2, with a time-space yield of 103.14,

[10] H2O2 is synthesized by non-equilibrium plasma reaction of H2 / O2, with a time-space yield of 36,

[13] methane is oxidized to H2O2 in a dual-medium plasma reactor, with a time-space yield of 3.18,

[39] H2 / O2 is synthesized to H2O2 by using multiple parallel DBD tubes, with a time-space yield of 18.33. Compared with the present invention, it can be clearly seen that the in-situ synthesis method of H2O2 based on low-temperature plasma driven hydrogen production of the present invention has an ultra-high time-space yield, which has achieved an exponential growth of about 27 times compared with the prior art.

[0051] Example 9

[0052] Under the optimal reaction conditions of Example 6, CO in the reaction gas was replaced with CO2, and it was found that H2O2 could still be prepared, with a space-time yield of 536.75 gH2O2 / L·h. This shows that in the CO, O2, and water vapor reaction system of the present invention, CO reacts with water vapor and O2 to generate H2O2 and CO2, wherein CO2 will further undergo a dissociation reaction in the plasma environment to generate CO and other active free radicals. These free radicals, such as CO, O, OH, and HO2, further participate in the generation of H2O2 through secondary reactions. Specifically, CO2 dissociates into active species such as CO and oxygen atoms (O) under the action of plasma:

[0053] CO2→ CO+O

[0054] The generated oxygen atoms (O) react with H2O to generate hydroxyl radicals (OH), and the OH radicals further react with O2 and other free radicals to generate H2O2. In this process, HO2 and OH radicals are the key intermediate species in the generation of H2O2:

[0055] O+H2O→2OH

[0056] 2OH→H2O2

[0057] OH+O2→HO2

[0058] 2HO2→H2O2+O2

[0059] In summary, in the CO, O2, and water vapor reaction system of the present invention, CO not only directly participates in the generation reaction of H2O2, but the generated CO2 also regenerates CO and other active free radicals through dissociation and secondary reactions, and participates in the generation of H2O2 again. This shows that CO and CO2 together form a circulation system in the plasma, which synergistically promotes the generation of H2O2 through multi-step reactions, ensuring the continuous progress of the reaction, which is one of the reasons why the present invention achieves a high H2O2 time-space yield.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for in-situ synthesis of H2O2 based on low-temperature plasma driven hydrogen production, characterized in that: Using CO, O2 and water vapor as raw materials, H2O2 is synthesized in situ in a plasma reactor; A steam generator is used to generate water vapor, and the peristaltic pump is used to precisely control the injection of water vapor. CO, O2, and water vapor are first mixed and then introduced into the plasma reactor. The specific input energy Q and gas residence time J in the plasma reactor meet the following requirements: ,in, , the unit of Q is kJ / L, the unit of J is s; The molar ratio of CO, O2, and water vapor is 1:(0,1):1, 1:0.6:(0,1), or (0,1):0.6:

1.

2. The H2O2 in-situ synthesis method according to claim 1, characterized in that: The H2O2 in-situ synthesis method is completed at normal temperature and pressure.

3. The H2O2 in-situ synthesis method according to claim 1, characterized in that: The plasma reactor is a corona discharge plasma reactor, a glow discharge plasma reactor, a jet plasma reactor or a dielectric barrier discharge reactor; the dielectric barrier discharge reactor is a flat dielectric barrier discharge reactor, a cylindrical dielectric barrier discharge reactor, a coaxial dielectric barrier discharge reactor or a multi-needle dielectric barrier discharge reactor, and the dielectric thickness is 1 mm.

4. The H2O2 in-situ synthesis method according to claim 3, characterized in that: The high-voltage electrode of the cylindrical dielectric barrier discharge reactor is made of copper rod, aluminum rod or tungsten rod, the grounding electrode is made of stainless steel, nickel, carbon material or salt solution, and the dielectric material is made of quartz glass, ceramic or polymer material.

5. The H2O2 in-situ synthesis method according to claim 1, characterized in that: The in-situ synthesized H2O2 is collected by condensation.

6. The H2O2 in-situ synthesis method according to claim 1, characterized in that: The molar ratio of CO, O2 and water vapor is 1:0.6:

1.

7. The H2O2 in-situ synthesis method according to claim 1, characterized in that: The specific input energy of the plasma reactor is 3-15 kJ / l and the gas residence time is 0.01-0.04 s.

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