Application of multifunctional catalysis-adsorbent sodium ferrite in coke gasification hydrogen production

Abstract

The invention discloses application of multifunctional catalysis-adsorbent sodium ferrite in coke gasification hydrogen production, and belongs to the technical field of gasification hydrogen production. The NaFeO2 has a good catalytic effect on gasification reaction in the process of hydrogen production through coke steam gasification and has high adsorption capacity on CO2, gasification hydrogen production is promoted through the Lunchaterow principle, and meanwhile products (Fe2O3 and Na2CO3) formed through the adsorption reaction have high catalytic effects on water-gas shift and the gasification reaction respectively. And the heat generated by the adsorption reaction indirectly reduces the reaction heat of the whole gasification. According to the multifunctional catalysis / adsorbent NaFeO2 provided by the invention, the H2 yield is 791.65 mL within 1 h, and the purity is as high as 97.3%.

Description

Technical Field

[0001] The invention relates to the technical field of gasification hydrogen production, and in particular to application of multifunctional catalyst-adsorbent sodium ferrite in coke gasification hydrogen production. Background Art

[0002] Due to the massive consumption of fossil fuels and the environmental problems caused by their combustion, hydrogen is recognized as one of the most promising renewable energy sources. The current mainstream hydrogen production method is highly dependent on fossil fuels, such as natural gas and coal. This production method produces a large amount of carbon dioxide, exacerbating global climate change and greenhouse effect. At present, relevant research has coupled carbon capture, utilization and storage technology (CCUS) with hydrogen production process, achieving CO2 emission reduction through in-situ CO2 capture, while improving H2 purity. Sodium-based catalysts are widely used in gasification hydrogen production processes, but traditional sodium-based catalysts have limited catalytic effect on water gas shift reaction, only have catalytic effect on gasification reaction, and have problems such as difficulty in adsorbing CO2 at low partial pressure. In addition, iron can form alloys or composite catalysts with other metals for various hydrogen production reactions. Iron-based oxide catalysts have been widely studied in high-temperature water gas shift reaction. They have high activity, good durability and relatively low manufacturing cost, but there are no reports on the research of iron oxide in enhanced gasification hydrogen production. Therefore, finding a material with superior adsorption performance and good catalytic performance throughout the gasification hydrogen production process is the key to improving the purity and output of H2. Summary of the invention

[0003] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art and to provide the application of multifunctional catalyst-adsorbent sodium ferrite in hydrogen production by coke gasification.

[0004] The technical solution of the present invention is as follows:

[0005] The multifunctional catalyst-adsorbent sodium ferrite is used in the production of hydrogen by coke gasification. The carbon source and sodium ferrite are mixed, heated, and reacted with water vapor to produce hydrogen.

[0006] As a preferred embodiment of the present invention, the molar ratio of the sodium ferrite to the carbon source is 0.25-1.

[0007] As a preferred embodiment of the present invention, the reaction temperature is 600-700°C.

[0008] As a preferred embodiment of the present invention, the carbon source includes one or more of wood, crop straw, herbaceous plants, and fossil carbon sources.

[0009] As a preferred embodiment of the present invention, the flow rate of water introduced during the reaction is 0.05-0.2 mL / min.

[0010] As a preferred embodiment of the present invention, nitrogen is introduced during the reaction, and the nitrogen flow rate is 50-150 mL / min.

[0011] As a preferred embodiment of the present invention, the purity of hydrogen is as high as 97.3%.

[0012] As a preferred embodiment of the present invention, sodium ferrite has catalytic effect and CO2 capture performance during the reaction process.

[0013] The beneficial effects of the present invention are as follows: the NaFeO2 used in the present invention has a good catalytic effect on the gasification reaction in the process of hydrogen production by coke steam gasification, and has a strong adsorption capacity for CO2, and promotes gasification hydrogen production through the Le Chatelier principle. At the same time, the products (Fe2O3 and Na2CO3) formed by the adsorption reaction have a strong catalytic effect on the water gas shift and gasification reaction respectively. The heat generated by the adsorption reaction indirectly reduces the overall reaction heat of gasification. The multifunctional catalyst / adsorbent NaFeO2 proposed in the present invention has a H2 production of 791.65 mL within 1 hour, and the purity is as high as 97.3%. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The drawings that constitute a part of this application are used to provide further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute improper limitations on this application.

[0015] Figure 1 The gas output and H2 purity of hydrogen produced by coke gasification under different comparison ratios;

[0016] Figure 2 Compare the effects of NaFeO2 and Na2CO3 on hydrogen production from coconut shell charcoal gasification at 650℃;

[0017] Figure 3 The effect of the molar ratio of NaFeO2 to C on the enhanced hydrogen production from coke gasification;

[0018] Figure 4 The effect of different temperatures on NaFeO2 enhanced coke gasification to produce hydrogen;

[0019] Figure 5 The gasification and hydrogen production performance of different carbon materials;

[0020] Figure 6 XRD patterns of NaFeO2 before and after hydrogen production reaction;

[0021] Figure 7 This is the performance diagram of NaFeO2 hydrogen production. DETAILED DESCRIPTION

[0022] The NaFeO2 described in the present invention is a highly efficient multifunctional catalyst / adsorbent, which has good catalytic performance throughout the gasification stage and excellent CO2 adsorption, and can maintain an effective adsorption effect even under low CO2 partial pressure.

[0023] To achieve the above object, the application of the multifunctional catalyst / adsorbent NaFeO2 in hydrogen production by coke gasification of the present invention comprises the following contents:

[0024] Different carbon sources are mixed with NaFeO2 at different molar ratios and temperatures to produce hydrogen;

[0025] Specifically, the molar ratio of NaFeO2 to the carbon source is 0.25-1, and the specific molar ratio can be 0.25, 0.5 or 1;

[0026] Specifically, the different temperatures are 600-700°C, and the specific molar ratio may be 600, 650 or 700°C;

[0027] In the specific implementation, the selected carbon source includes but is not limited to one or more of wood, crop straw, herbaceous plants, and fossil carbon sources, and specifically can be bamboo charcoal, coconut shell charcoal, anthracite, and bituminous coal, but is not limited thereto;

[0028] More specifically, the NaFeO2 includes but is not limited to at least one of various NaFeO2 forms such as high-purity NaFeO2, NaFeO2 containing specific impurities, and NaFeO2 of different crystal forms.

[0029] Preferably, the adsorbent in the hydrogen production process is NaFeO2, which will generate Fe2O3 and Na2CO3 during adsorption; that is, the gasification reaction catalyst in the hydrogen production process is NaFeO2 and the sodium component Na2CO3 produced in the adsorption reaction, and the water gas shift reaction catalyst is the iron component Fe2O3 produced in the adsorption reaction.

[0030] Furthermore, bamboo charcoal, calcium oxide plus bamboo charcoal, and NaFeO2 plus bamboo charcoal were used to produce hydrogen under the same experimental conditions and the effects were compared;

[0031] In the specific implementation, NaFeO2 and Na2CO3 were used to produce hydrogen from coconut shell charcoal under the same experimental conditions and the effects were compared;

[0032] In specific implementation, NaFeO2 and its by-products in the hydrogen production process can be analyzed by XRD analysis to further verify the catalytic effect of NaFeO2 on gasification and water-gas shift reactions and the adsorption effect on carbon dioxide.

[0033] Various exemplary embodiments of the present invention will be described in detail herein to further explain the technical solution of the present invention. This detailed description should not be regarded as a constraint on the present invention, but should be understood as a more detailed explanation of some aspects, features and implementation plans of the present invention.

[0034] For the numerical ranges in the present invention, it is understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any intermediate value in the stated value or stated range and any other stated value or intermediate value in the stated range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the range.

[0035] The example of the present invention discloses a multifunctional catalyst / adsorbent NaFeO2, and the products (Fe2O3 and Na2CO3) formed by its adsorption reaction have strong catalytic effects on water gas shift and gasification reactions respectively.

[0036] Comparative Example 1

[0037] 1g bamboo charcoal was gasified to produce hydrogen at 700℃, water flow rate of 0.1mL / min, and N2 flow rate of 100mL / min. After the reaction, the CO2 output was 90.17mL, the H2 output was 93.74mL, and the purity was only 39.9%. For details, see Figure 1 .

[0038] Comparative Example 2

[0039] Referring to Comparative Example 1, the reaction was carried out under the condition that the molar ratio of CaO to bamboo charcoal was 0.5:1. After the reaction, the CO2 production was 145.15 mL, the H2 production was 188.07 mL, and the purity was 49.29%. Figure 1 After adding CaO that can adsorb CO2, although the concentration and output of H2 have increased, the increase is very small and the purity of H2 is still very low.

[0040] Comparative Example 3

[0041] Refer to Comparative Example 2, replace CaO with NaFeO2 for the experiment. Under the same conditions, the CO2 output is 215.00mL, the H2 output is 985.84mL, and the H2 purity is 69.3%. For details, see Figure 1 Due to the catalytic effect of NaFeO2, the H2 concentration and output were greatly increased, and the CO2 concentration was greatly reduced, proving that the adsorption effect of NaFeO2 is much stronger than that of CaO.

[0042] Comparative Example 4

[0043] The adsorption and catalytic effects of NaFeO2 were evaluated by equimolar Na2CO3. Figure 2 As shown in the figure, when Na2CO3 was used to catalyze the production of hydrogen by coconut shell charcoal at 650℃, the H2 production was 146.99mL with a purity of 49.73%. When NaFeO2 was used as a catalyst, the H2 production was 722.78mL with a purity of 93.31%. The results show that the catalytic effect of NaFeO2 is stronger than that of Na2CO3.

[0044] Example 1

[0045] The molar ratio of NaFeO2 to C was changed (0.25:1, 0.5:1, 0.75:1, 1:1 respectively). As the molar ratio of NaFeO2 to C increased, the real-time concentration of H2 increased to a certain extent. From 0.25:1 to 1:1, the H2 concentration increased from 78.5% to 97.3%. In contrast, the real-time concentrations of CO and CO2 decreased with the increase of the molar ratio. From the perspective of gas production, at 0.25:1, the CO production was 35.93mL, the CO2 production was 127.82mL, and the H2 production was 620.02mL. When the molar ratio increased to 1:1, the CO production was only 4.58mL, and the CO2 production was only 15.02mL, which was much lower than 0.25:1. At this time, the H2 production was the highest, at 791.65mL, 27.7% more than at 0.25:1, and the H2 purity was 97.3%. The results show that the greater the molar ratio of NaFeO2 to C, the higher the H2 purity, which can be adjusted according to actual needs. Figure 3 .

[0046] Example 2

[0047] The NaFeO2 parallel experiment temperatures were 600℃, 650℃ and 700℃ respectively. Change the experimental temperature and monitor the generated gas and its concentration changes. In practice, the optimal temperature can be selected by comprehensively considering the H2 purity and output. For details, see Figure 4 .

[0048] Example 3

[0049] During the experiment, different carbon sources were replaced to study the applicability of NaFeO2 in the field of hydrogen production. The H2 production of anthracite was 801.87 mL. The H2 production of bituminous coal was 565.38 mL. The H2 purity of anthracite was the lowest, at 86.8%. In contrast, although the H2 production of coconut shell charcoal was slightly lower than that of anthracite, its purity was as high as 93.3%, which was 6.5% higher than that of anthracite. Considering the H2 purity and production comprehensively, coconut shell charcoal had the best hydrogen production performance. In addition, the study also noted that the hydrogen production performance of the four carbon materials under the enhancement of NaFeO2 was not much different, indicating that NaFeO2 has a wide range of applicability in enhancing the hydrogen production performance of carbon materials and has low requirements for carbon materials. See for details. Figure 5 .

[0050] Example 4

[0051] By comparing the XRD patterns of NaFeO2 before and after hydrogen production, the changes of the samples before and after the hydrogen production reaction can be observed. The results show that the diffraction peak of NaFeO2 is dominant before hydrogen production, indicating that the purity of NaFeO2 prepared by the present invention is relatively high. The diffraction peak of NaFeO2 basically disappears after the hydrogen production reaction, and the XRD pattern shows that the diffraction peaks are mainly Na2CO3 and Fe2O3. For details, see Figure 6 . It shows that NaFeO2 not only plays a catalytic role in the hydrogen production process, but also plays a role in adsorbing CO2, and the adsorption process will produce Na2CO3 that has a catalytic effect on the gasification reaction and Fe2O3 that has a catalytic effect on the water gas shift reaction.

[0052] The present invention explores the effect of NaFeO2 on gasification hydrogen production under different conditions. The results show that under the conditions of carrier gas flow rate of 50mL / min, water flow rate of 0.1mL / min, and 650℃, the best effect is achieved when the molar ratio of NaFeO2 to coconut shell charcoal is 1:1. The H2 output is 791.65mL and the purity is as high as 97.3%, indicating that NaFeO2 has extremely strong catalytic performance. For details, see Figure 3 .

[0053] The real-time CO2 concentration was almost zero within 30 minutes after the NaFeO2 hydrogen production reaction began, and then slowly rose to 0.92%. This result shows that NaFeO2 has a very strong CO2 capture performance. Figure 7 .

[0054] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. Application of multifunctional catalyst-adsorbent sodium ferrite in hydrogen production by coke gasification, characterized in that: The carbon source and sodium ferrite are mixed, heated, and reacted with water vapor to produce hydrogen.

2. The use of the multifunctional catalyst-adsorbent sodium ferrite in hydrogen production by coke gasification according to claim 1, characterized in that: The molar ratio of the sodium ferrite to the carbon source is 0.25-1.

3. The use of the multifunctional catalyst-adsorbent sodium ferrite in hydrogen production by coke gasification according to claim 1, characterized in that: The reaction temperature is 600-700°C.

4. The use of the multifunctional catalyst-adsorbent sodium ferrite in hydrogen production by coke gasification according to claim 1, characterized in that: The carbon source includes one or more of wood, crop straw, herbaceous plants, and fossil carbon sources.

5. The use of the multifunctional catalyst-adsorbent sodium ferrite in hydrogen production by coke gasification according to claim 1, characterized in that: The purity of hydrogen is as high as 97.3%.

6. The use of the multifunctional catalyst-adsorbent sodium ferrite in hydrogen production by coke gasification according to claim 1, characterized in that: Sodium ferrite has catalytic effects in the reaction process as well as CO2 capture properties.

Images