Biomass hydrogen production method and two-section type regenerated adsorbent hydrogen production device

Abstract

The invention discloses a biomass hydrogen production method, which comprises: S1, carrying out a gasification reaction on a biomass raw material and water vapor in a gasification reactor to generate a mixed gas; s2, the mixed gas obtained in the step S1 reacts with water vapor and an adsorbent in an adsorption enhancement reactor to generate carbonate, and hydrogen-rich gas is collected; s3, the carbonate obtained through the reaction in the step S2 reacts with water vapor in a regeneration adsorbent reactor, and a product obtained through the reaction enters the adsorption enhancement reactor to be used as an adsorbent. According to the hydrogen production method, the gasification reactor and the adsorption enhancement reactor are arranged, and an exothermic reaction is carried out in the adsorption enhancement reactor, so that the effect of producing hydrogen at a relatively low temperature can be realized.

Description

Technical Field

[0001] The present invention relates to the field of biomass hydrogen production, and in particular to a biomass hydrogen production method and a two-stage and regenerative adsorbent hydrogen production device. Background Art

[0002] As a renewable energy source, biomass offers numerous advantages, including widespread availability, abundant reserves, and environmental friendliness, demonstrating tremendous potential for development in the energy sector. Biomass gasification hydrogen production technology, a key biomass energy conversion method, can transform biomass into a hydrogen-rich gas mixture, providing a new avenue for clean energy production.

[0003] In the current field of biomass gasification hydrogen production, there are many key technical issues that need to be addressed. First, the traditional biomass gasification hydrogen production process requires high gasification temperature and pressure, typically maintaining the reaction temperature at 800-1000°C. To increase hydrogen production and purity, the reaction pressure usually needs to be increased to 1-3MPa. This hydrogen production method results in high energy consumption, making the entire hydrogen production process lack economic and sustainable energy utilization. Summary of the Invention

[0004] The purpose of the present invention is to provide a biomass hydrogen production method and a two-stage and regenerative adsorbent hydrogen production device. The biomass hydrogen production method can achieve the effect of hydrogen production at a lower temperature by setting two reactors, a gasification reactor and an adsorption enhancement reactor, and performing an exothermic reaction in the adsorption enhancement reactor.

[0005] In order to achieve the above object, the present invention provides a method for producing hydrogen from biomass, comprising the following steps:

[0006] S1, gasifying the biomass raw material and water vapor in a gasification reactor to generate a mixed gas;

[0007] S2, the mixed gas obtained in step S1 reacts with water vapor and an adsorbent in an adsorption enhancement reactor to generate carbonate, and the hydrogen-rich gas is collected;

[0008] S3, the carbonate obtained by the reaction in step S2 reacts with water vapor in a regenerated adsorbent reactor, and the product obtained by the reaction enters an adsorption enhancement reactor for use as an adsorbent;

[0009] The reaction pressure in the gasification reactor, adsorption enhancement reactor and regeneration adsorbent reactor is 0.1-0.5 MPa. Preferably, in step S1, the gasification reaction conditions include: temperature of 600-800°C and water vapor atmosphere of 40%-60%.

[0010] Preferably, in step S2, the reaction conditions include: the reaction temperature is 500 - 700 °C, and the water vapor atmosphere is 40% - 60%.

[0011] Preferably, in step S3, the reaction conditions include: the reaction temperature is 900 - 1200 °C, and the water vapor atmosphere is 55% - 60%.

[0012] Preferably, the adsorbent added in S2 is calcium hydroxide or calcium oxide.

[0013] Preferably, in S3, alumina is added to the regenerated adsorbent reactor.

[0014] Preferably, the mass ratio of alumina to the adsorbent is (0.3 - 0.5):1.

[0015] The present invention also provides a two-stage and regenerated adsorbent hydrogen production device, including a gasification reactor, an adsorption-enhanced reactor, and a regenerated adsorbent reactor. The gasification reactor and the adsorption-enhanced reactor are connected through a gas pipe. A first conveying pipe and a second conveying pipe are arranged between the adsorption-enhanced reactor and the regenerated adsorbent reactor, and the conveying directions in the first conveying pipe and the second conveying pipe are opposite;

[0016] The gasification reactor is provided with a first feed port and a first steam inlet. The adsorption-enhanced reactor is provided with a hydrogen collection pipe, a third steam inlet, and a second feed port. The regenerated adsorbent reactor is provided with a carbon dioxide collection pipe and a second steam inlet.

[0017] Preferably, the gasification reactor, the adsorption-enhanced reactor, and the regenerated adsorbent reactor are respectively provided with heating devices.

[0018] According to the above technical solution, in the biomass hydrogen production method provided by the present invention, first, the biomass and water vapor are subjected to a gasification reaction in the gasification reactor to produce hydrogen. The main chemical reaction is: (endothermic), which is a reversible reaction. The reaction temperature is 600 °C - 800 °C. The mixed gas generated by the gasification hydrogen production reaction enters the adsorption-enhanced reactor and undergoes an adsorption-enhanced reaction in the adsorption-enhanced reactor. The main process is that the adsorbent adsorbs carbon dioxide, promoting the forward chemical reaction of the water gas and thus increasing the hydrogen production.

[0019] Preferably, the adsorbent is selected from one or two or more of calcium hydroxide and calcium oxide.

[0020] Taking calcium oxide as the adsorbent, the main chemical reaction occurring in the adsorption-enhanced reactor is: CO2(g) + CaO(s) = CaCO3(s). In the sorption-enhanced reactor, carbon monoxide first reacts with steam to produce carbon dioxide and hydrogen, and then the carbon dioxide reacts with the sorbent to form calcium carbonate. Since the reaction carried out in the sorption-enhanced reactor is an exothermic reaction with a reaction temperature of 500°C - 700°C, the sorption-enhanced reactor only requires a relatively low reaction temperature to achieve the adsorption of carbon dioxide, enabling the water-gas shift reaction to proceed in the forward direction, thereby increasing the hydrogen production.

[0021] The reaction pressures in both the gasification reactor and the sorption-enhanced reactor are 0.1 - 0.5 MPa, and no special pressurization is required. The reaction temperature in the gasification reactor is 600°C - 800°C, and the reaction temperature in the sorption-enhanced reactor is 500°C - 700°C. Therefore, by setting up the sorption-enhanced reactor, an efficient hydrogen production effect can be achieved under the conditions of a relatively low temperature and normal pressure.

[0022] In the sorption-enhanced reactor, after carbon monoxide reacts with steam to produce carbon dioxide, the carbon dioxide is absorbed by the sorbent, generating hydrogen. Without adding new impurity gases, through the adsorption effect, on the one hand, the carbon monoxide in the mixed gas produced by the gasification reactor is reduced, and at the same time, the hydrogen content in the mixed gas can be increased. Therefore, setting up the sorption-enhanced reactor can achieve the purification effect of hydrogen.

[0023] The product of the adsorption reaction enters the regenerative sorbent reactor. Through high-temperature calcination, calcium carbonate decomposes into calcium oxide, and then the produced calcium oxide reacts with steam to form calcium hydroxide, CaCO3 + H2O(g) → Ca(OH)2 + CO2. Sending the produced calcium hydroxide back to the sorption-enhanced reactor for use as a regenerated sorbent can realize the recycling of the sorbent.

[0024] Other features and advantages of the present invention will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific implementation, they are used to explain the present invention, but do not constitute a limitation to the present invention. In the drawings:

[0026] Figure 1 is a schematic diagram of a two-stage and regenerative sorbent hydrogen production device of the present invention;

[0027] Figure 2 is a hydrogen production characteristic diagram when the temperatures of the gasification reactor and the sorption-enhanced reactor in Examples 1 - 8 of the present invention are the same;

[0028] Figure 3 is a hydrogen production characteristic diagram of Comparative Examples 1 - 12 of the present invention using a single gasification reactor;

[0029] Figure 4 It is the hydrogen production characteristic diagram of Examples 9-20 of the present invention using a gasification reactor and an adsorption-enhanced reactor;

[0030] Figure 5 It is the hydrogen production characteristic diagram of Example 22 of the present invention after five cycles;

[0031] Figure 6 It is the XRD diagram of the adsorbent used in Examples 21 and 22 of the present invention after cyclic use;

[0032] Figure 7 It is the SEM diagram of the adsorbent used in Examples 21 and 22 of the present invention after cyclic use.

[0033] Explanation of reference numerals

[0034] 1 Gasification reactor 2 Adsorption-enhanced reactor

[0035] 3 Regenerated adsorbent reactor 4 Gas pipe

[0036] 5 First delivery pipe 6 Second delivery pipe

[0037] 11 First feed inlet 12 First steam inlet

[0038] 21 Hydrogen collection pipe 23 Second feed inlet

[0039] 31 Carbon dioxide collection pipe 32 Second steam inlet

[0040] 33 Control valve 34 Third steam inlet Detailed implementation manners

[0041] The following further elaborates on the detailed implementation manners of the present invention with reference to the accompanying drawings. It should be understood that the detailed implementation manners described herein are only for the purpose of illustration and explanation of the present invention, and are not intended to limit the present invention.

[0042] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0043] On the one hand, the present invention provides a method for producing hydrogen from biomass, which includes the following steps:

[0044] S1. Carry out a gasification reaction on the biomass raw material and water vapor in the gasification reactor 1 to generate a mixed gas;

[0045] S2. The mixed gas obtained in step S1 reacts with water vapor and an adsorbent in the adsorption-enhanced reactor 2 to produce carbonate, and the hydrogen-rich gas is collected.

[0046] S3. The carbonate obtained from the reaction in step S2 reacts with water vapor in the regenerative adsorbent reactor 3, and the product obtained from the reaction enters the adsorption-enhanced reactor 2 for use as an adsorbent.

[0047] Among them, the reaction pressures in the gasification reactor 1, the adsorption-enhanced reactor 2, and the regenerative adsorbent reactor 3 are 0.1 - 0.5 MPa.

[0048] In a preferred embodiment of the present invention, the biomass raw material is derived from any substance containing lignocellulose.

[0049] In the above biomass hydrogen production method, the biomass raw material can be derived from any substance containing lignocellulose, such as forestry residues or agricultural residues, and more specifically can be any substance containing lignocellulose such as wheat bran, bagasse, poplar sawdust, lignin, etc.

[0050] The shape of the raw material can be any shape including sheet, round, cylindrical, conical, square, irregular shape, etc.

[0051] In a preferred embodiment of the present invention, in step S1, the conditions for the gasification reaction include: the temperature is 600 - 800 °C, and the water vapor atmosphere is 40 - 60%.

[0052] In a preferred embodiment of the present invention, in step S2, the reaction conditions include: the reaction temperature is 500 - 700 °C, and the water vapor atmosphere is 40% - 60%.

[0053] In the biomass hydrogen production method provided by the present invention, first, the biomass reacts with water vapor in a gasification reactor to produce hydrogen by gasification. The main chemical reaction is: (endothermic), which is a reversible reaction. The reaction temperature is 600 °C - 800 °C. The mixed gas generated by the gasification hydrogen production reaction enters the adsorption-enhanced reactor, and an adsorption-enhanced reaction occurs in the adsorption-enhanced reactor. The main process is that the adsorbent adsorbs carbon dioxide, making the water-gas shift proceed forward, thereby increasing the hydrogen production.

[0054] Preferably, the adsorbent is selected from one or more of calcium hydroxide and calcium oxide.

[0055] Taking calcium oxide as the adsorbent, the main chemical reaction occurring in the adsorption-enhanced reactor is: CO2(g) + CaO(s) = CaCO3(s). In the sorption-enhanced reactor, carbon monoxide first reacts with steam to produce carbon dioxide and hydrogen. Subsequently, the carbon dioxide reacts with the sorbent, and the hydrogen produced reacts with calcium oxide to form calcium carbonate. Since the reaction in the sorption-enhanced reactor is an exothermic reaction with a reaction temperature of 500°C - 700°C, the sorption-enhanced reactor only requires a relatively low reaction temperature to achieve the adsorption of carbon dioxide, enabling the water-gas shift reaction to proceed in the forward direction, thereby increasing the hydrogen yield.

[0056] The reaction pressures in both the gasification reactor and the sorption-enhanced reactor are 0.1 - 0.5 MPa, and no special pressurization is required. The reaction temperature in the gasification reactor is 600°C - 800°C, and the reaction temperature in the sorption-enhanced reactor is 500°C - 700°C. Therefore, by setting up the sorption-enhanced reactor, an efficient hydrogen production effect can be achieved under the conditions of a relatively low temperature and normal pressure.

[0057] In the sorption-enhanced reactor, after carbon monoxide reacts with steam to produce carbon dioxide, it is absorbed by the sorbent, generating hydrogen. Without adding new impurity gases, through the adsorption effect, on the one hand, the carbon monoxide in the mixed gas produced by the gasification reactor is reduced, and at the same time, the hydrogen content in the mixed gas can be increased. Therefore, setting up the sorption-enhanced reactor can achieve the purification effect of hydrogen.

[0058] The product of the adsorption reaction enters the regenerative sorbent reactor. Calcium carbonate decomposes into calcium oxide through high-temperature calcination. Subsequently, the calcium oxide produced reacts with steam to form calcium hydroxide, CaCO3 + H2O(g) → Ca(OH)2 + CO2. Sending the generated calcium hydroxide back to the sorption-enhanced reactor for use as a regenerated sorbent can realize the recycling of the sorbent.

[0059] Compared with the traditional high-temperature and high-pressure gasification hydrogen production method, when using the biomass hydrogen production method of this application, only under normal pressure can a relatively high hydrogen yield be obtained.

[0060] Example 1:

[0061] (1) Weigh 1.382 g of wheat bran and add it to the gasification reactor 1. Input steam into the gasification reactor 1 at a speed of 70 mL / min, control the temperature of the gasification reactor 1 to be 800°C, the pressure to be 0.1 - 0.5 MPa, and the steam atmosphere to be 40% - 60%. React to produce a mixed gas of hydrogen and carbon dioxide;

[0062] (2) Feed the mixed gas generated in step (1) into the sorption-enhanced reactor 2. Meanwhile, weigh 3.251 g of calcium hydroxide as the adsorbent and add it to the sorption-enhanced reactor 2. Control the temperature in the sorption-enhanced reactor 2 at 800 °C, the steam atmosphere at 40%-60%, and the pressure at 0.1-0.5 MPa. The calcium hydroxide absorbs carbon dioxide in the mixed gas to form calcium carbonate, and collect the remaining mixed gas;

[0063] In the collected gas, the hydrogen concentration is 74.73%, and the hydrogen production is 209.63 mL.

[0064] Example 2

[0065] Carry out the experiment according to the method of Example 1, except that the temperatures in both the gasification reactor 1 and the sorption-enhanced reactor 2 are controlled at 600 °C.

[0066] In the collected gas, the hydrogen concentration is 75.22%, and the hydrogen production is 132.68 mL.

[0067] Example 3

[0068] Carry out the experiment according to the method of Example 1, except that wheat bran is replaced by bagasse.

[0069] In the collected gas, the hydrogen concentration is 74.36%, and the hydrogen production is 212.97 mL.

[0070] Example 4

[0071] Carry out the experiment according to the method of Example 1, except that wheat bran is replaced by bagasse, and the temperatures in both the gasification reactor 1 and the sorption-enhanced reactor 2 are controlled at 600 °C.

[0072] In the collected gas, the hydrogen concentration is 73.71%, and the hydrogen production is 162.39 mL.

[0073] Example 5

[0074] Carry out the experiment according to the method of Example 1, except that wheat bran is replaced by poplar sawdust.

[0075] In the collected gas, the hydrogen concentration is 79.98%, and the hydrogen production is 204.37 mL.

[0076] Example 6

[0077] Carry out the experiment according to the method of Example 1, except that wheat bran is replaced by poplar sawdust, and the temperatures in both the gasification reactor 1 and the sorption-enhanced reactor 2 are controlled at 600 °C.

[0078] In the collected gas, the hydrogen concentration is 80.42%, and the hydrogen production is 121.66 mL.

[0079] Example 7

[0080] It was carried out according to the method of Example 1, except that wheat bran was replaced by lignin.

[0081] In the collected gas, the hydrogen concentration was 74.36%, and the hydrogen production was 543.28 mL.

[0082] Example 8

[0083] It was carried out according to the method of Example 1, except that wheat bran was replaced by lignin, and at the same time, the temperatures of the gasification reactor 1 and the adsorption-enhanced reactor 2 were both controlled at 600 °C.

[0084] In the collected gas, the hydrogen concentration was 79.68%, and the hydrogen production was 102.37 mL.

[0085] The experimental results of Examples 1-8 are shown in Table 1:

[0086] Table 1

[0087]

[0088] Comparative Example 1:

[0089] (1) Weigh 1.382 g of wheat bran and 3.251 g of calcium hydroxide and add them to the gasification reactor 1. Input steam into the gasification reactor 1 at a speed of 70 mL / min. Control the temperature of the gasification reactor 1 at 600 °C, the steam atmosphere at 40%-60%, and the pressure at 0.1-0.5 MPa. React to generate a mixed gas of hydrogen and carbon dioxide, and collect the remaining mixed gas;

[0090] In the collected gas, the hydrogen concentration was 60.93%, and the hydrogen production was 106.47 ml;

[0091] [[ID=3,7]]Comparative Example 2:

[0092] It was carried out according to the method of Comparative Example 1, except that the temperature of the gasification reactor 1 was controlled at 700 °C.

[0093] In the collected gas, the hydrogen concentration was 59.56%, and the production was 139.23 ml;

[0094] Comparative Example 3:

[0095] It was carried out according to the method of Comparative Example 1, except that the temperature of the gasification reactor 1 was controlled at 800 °C.

[0096] In the collected gas, the hydrogen concentration was 59.56%, and the production was 205.83 ml.

[0097] Comparative Example 4:

[0098] It was carried out according to the method of Comparative Example 1, except that wheat bran was replaced with bagasse.

[0099] In the collected gas, the hydrogen concentration was 60.23%, and the hydrogen production was 139.23 ml;

[0100] Comparative Example 5:

[0101] It was carried out according to the method of Comparative Example 1, except that wheat bran was replaced with bagasse, and at the same time, the temperature of the gasification reactor 1 was controlled at 700 °C.

[0102] In the collected gas, the hydrogen concentration was 56.57%, and the production was 163.81 ml;

[0103] Comparative Example 6:

[0104] It was carried out according to the method of Comparative Example 1, except that wheat bran was replaced with bagasse, and at the same time, the temperature of the gasification reactor 1 was controlled at 800 °C.

[0105] In the collected gas, the hydrogen concentration was 57.83%, and the production was 204.75 ml.

[0106] Comparative Example 7:

[0107] It was carried out according to the method of Comparative Example 1, except that wheat bran was replaced with poplar sawdust.

[0108] In the collected gas, the hydrogen concentration was 63.04%, and the hydrogen production was  98.28 ml;

[0109] Comparative Example 8:

[0110] It was carried out according to the method of Comparative Example 1, except that wheat bran was replaced with poplar sawdust, and at the same time, the temperature of the gasification reactor 1 was controlled at 700 °C.

[0111] In the collected gas, the hydrogen concentration was 61.11%, and the production was 122.85 ml;

[0112] Comparative Example 9:

[0113] It was carried out according to the method of Comparative Example 1, except that wheat bran was replaced with poplar sawdust, and at the same time, the temperature of the gasification reactor 1 was controlled at 800 °C.

[0114] In the collected gas, the hydrogen concentration was 62.65%, and the production was 166.87 ml.

[0115] Comparative Example 10:

[0116] It was carried out according to the method of Comparative Example 1, except that wheat bran was replaced with lignin.

[0117] In the collected gas, the hydrogen concentration was 68.42%, and the hydrogen production was 89.32 ml;

[0118] Comparative Example 11:

[0119] It was carried out according to the method of Comparative Example 1, except that wheat bran was replaced with lignin, and at the same time, the temperature of the gasification reactor 1 was controlled at 700 °C.

[0120] In the collected gas, the hydrogen concentration was 61.28%, and the production was 202.14 ml;

[0121] Comparative Example 12:

[0122] It was carried out according to the method of Comparative Example 1, except that wheat bran was replaced with lignin, and at the same time, the temperature of the gasification reactor 1 was controlled at 800 °C.

[0123] In the collected gas, the hydrogen concentration was 44.57%, and the production was 414.93 ml.

[0124] The experimental results of Comparative Examples 1-12 are shown in Table 2:

[0125] Table 2

[0126]

[0127] By comparing Example 2 and Comparative Example 1, it can be seen that: when using the same mass of wheat bran and adsorbent and at a reaction temperature of 600 °C, adding wheat bran and adsorbent to the gasification reactor 1 and the adsorption-enhanced reactor 2 respectively produced a higher hydrogen concentration than adding wheat bran and adsorbent to the gasification reactor 1 simultaneously, and the hydrogen production also increased slightly.

[0128] By comparing Example 1 and Comparative Example 3, it can be seen that: when using the same mass of wheat bran and adsorbent and at a reaction temperature of 800 °C, adding wheat bran and adsorbent to the gasification reactor 1 and the adsorption-enhanced reactor 2 respectively produced a higher hydrogen concentration than adding wheat bran and adsorbent to the gasification reactor 1 simultaneously, and the hydrogen production also increased significantly.

[0129] By comparing Examples 1-8 with Comparative Examples 1-12 respectively, it can be seen that:

[0130] When the temperatures of the gasification reactor 1 and the sorption-enhanced reactor 2 are set to be the same, the hydrogen concentration obtained by separately adding biomass and sorbent to the gasification reactor 1 and the sorption-enhanced reactor 2 is significantly higher than that when biomass and sorbent are simultaneously added to the gasification reactor 1. This is because when both biomass and sorbent are added to the gasification reactor 1, the gasification reaction produces carbon monoxide and hydrogen, and the sorbent only adsorbs carbon dioxide. However, the content of carbon dioxide at this time is not high, so the overall adsorption reaction is not obvious. But when the sorbent is added to the sorption-enhanced reactor 2, the carbon monoxide produced by the gasification reactor enters the sorption-enhanced reactor 2 and reacts with the water vapor in the sorption-enhanced reactor 2 to produce carbon dioxide. At this time, the adsorption reaction can occur more effectively, thus achieving the effect of hydrogen purification. Therefore, by setting the gasification reactor 1 and the sorption-enhanced reactor 2 to carry out gasification reaction and adsorption reaction respectively, the hydrogen concentration can be significantly increased.

[0131] When the temperature is set to 800 °C, whether biomass and sorbent are separately added to the gasification reactor 1 and the sorption-enhanced reactor 2 or simultaneously added to the gasification reactor 1, the hydrogen production will increase compared to the hydrogen production at a temperature of 600 °C. This is because the gasification reaction is more likely to occur at 800 °C. However, the hydrogen concentration decreases compared to the hydrogen concentration at a reaction temperature of 600 °C. This is because the adsorption reaction is more likely to occur at 600 °C.

[0132] When the biomass material is set to lignin, the hydrogen production is the highest. This is because under the same mass, lignin contains more hydrogen elements and can decompose more hydrogen during the gasification reaction.

[0133] Therefore, when the temperature of the gasification reactor 1 is 800 °C, the hydrogen production effect is the best. However, 800 °C is not conducive to the occurrence of the adsorption reaction. Moreover, when using the same mass of biomass material, the hydrogen production of lignin is the highest.

[0134] Analyzing the data of Examples 1-8, it can be seen that when the temperatures of both the gasification reactor 1 and the sorption-enhanced reactor 2 are set to 800 °C, the hydrogen production effect is the best and more hydrogen can be produced.

[0135] Because the chemical reaction occurring in the gasification reactor 1 is The reaction occurring in the sorption-enhanced reactor 2 is CO2(g)+CaO(s)=CaCO3(s). Therefore, considering that the gasification reaction in the gasification reactor 1 needs to be carried out in a high-temperature environment, while the reaction in the sorption-enhanced reactor 2 is an exothermic reaction, high temperature may inhibit the reaction process in the sorption-enhanced reactor 2.

[0136] Example 9:

[0137] (1) Weigh 1.382 g of wheat bran and add it to the gasification reactor 1. Input steam into the gasification reactor 1 at a rate of 70 mL / min, control the temperature of the gasification reactor 1 at 800 °C, the steam atmosphere at 40%-60%, and the pressure at 0.1-0.5 MPa to react and generate a mixed gas of hydrogen and carbon dioxide;

[0138] (2) Pass the mixed gas generated in step (1) into the adsorption-enhanced reactor 2. At the same time, weigh 3.251 g of calcium hydroxide as the adsorbent and add it to the adsorption-enhanced reactor 2. Input steam into the adsorption-enhanced reactor 2 at a rate of 70 mL / min, control the temperature in the adsorption-enhanced reactor 2 at 500 °C, the steam atmosphere at 40%-60%, and the pressure at 0.1-0.5 MPa. Calcium hydroxide absorbs carbon dioxide in the mixed gas to form calcium carbonate, and collect the remaining mixed gas;

[0139] In the collected gas, the hydrogen concentration is 73.37% and the hydrogen production is 233.72 mL.

[0140] Example 10:

[0141] Conduct the experiment according to the method of Example 9, except that the temperature in the adsorption-enhanced reactor 2 is controlled at 600 °C.

[0142] In the collected gas, the hydrogen concentration reaches 75.61% and the hydrogen production is 260.43 mL;

[0143] Example 11

[0144] Conduct the experiment according to the method of Example 9, except that the temperature in the adsorption-enhanced reactor 2 is controlled at 700 °C.

[0145] In the collected gas, the hydrogen concentration is 74.59% and the hydrogen production is 217.15 mL.

[0146] Example 12

[0147] Conduct the experiment according to the method of Example 9, except that the wheat bran is replaced with bagasse.

[0148] In the collected gas, the hydrogen concentration is 70.37% and the hydrogen production is 237.12 mL;

[0149] Example 13

[0150] Conduct the experiment according to the method of Example 9, except that the wheat bran is replaced with bagasse and the temperature in the adsorption-enhanced reactor 2 is controlled at 600 °C.

[0151] In the collected gas, the hydrogen concentration reaches 74.15% and the hydrogen production is 243.69 mL;

[0152] Example 14

[0153] It was carried out according to the method of Example 9, except that wheat bran was replaced with bagasse, and at the same time, the temperature in the sorption-enhanced reactor 2 was controlled at 700 °C.

[0154] In the collected gas, the hydrogen concentration was 74.15%, and the hydrogen production was 229.17 mL.

[0155] Example 15

[0156] It was carried out according to the method of Example 9, except that wheat bran was replaced with poplar sawdust, and at the same time, the temperature in the sorption-enhanced reactor 2 was controlled at 500 °C.

[0157] In the collected gas, the hydrogen concentration was 85.71%, and the hydrogen production was 297.56 mL;

[0158] Example 16

[0159] It was carried out according to the method of Example 9, except that wheat bran was replaced with poplar sawdust, and at the same time, the temperature in the sorption-enhanced reactor 2 was controlled at 600 °C.

[0160] In the collected gas, the hydrogen concentration reached 87.69%, and the hydrogen production was 304.37 mL;

[0161] Example 17

[0162] It was carried out according to the method of Example 9, except that wheat bran was replaced with poplar sawdust, and at the same time, the temperature in the sorption-enhanced reactor 2 was controlled at 700 °C.

[0163] In the collected gas, the hydrogen concentration was 89.32%, and the hydrogen production was 264.89 mL.

[0164] Example 18

[0165] It was carried out according to the method of Example 9, except that wheat bran was replaced with lignin.

[0166] In the collected gas, the hydrogen concentration was 76.88%, and the hydrogen production was 603.81 mL;

[0167] Example 19

[0168] It was carried out according to the method of Example 9, except that wheat bran was replaced with lignin, and at the same time, the temperature in the sorption-enhanced reactor 2 was controlled at 600 °C.

[0169] In the collected gas, the hydrogen concentration reached 77.67%, and the hydrogen production was 647.67 mL;

[0170] Example 20

[0171] It was carried out according to the method of Example 9, except that wheat bran was replaced by lignin, and at the same time, the temperature in the sorption-enhanced reactor 2 was controlled at 700 °C.

[0172] In the collected gas, the hydrogen concentration was 73.62%, and the hydrogen production was 589.21 mL.

[0173] The experimental results of Examples 9-20 are shown in Table 3:

[0174] Table 3

[0175]

[0176] In the experiments of Examples 9-20, the experimental temperature of the gasification reactor 1 was set at 800 °C in order to produce the most hydrogen in the gasification reactor 1, and at the same time, the temperature change in the sorption-enhanced reactor 2 was controlled to seek the optimal hydrogen production temperature combination.

[0177] According to the experimental data of Examples 9-20, it can be seen that the highest hydrogen production data among the four biomasses all occurred when the temperature of the gasification reactor 1 was set at 800 °C and the temperature of the sorption-enhanced reactor 2 was set at 600 °C.

[0178] When the temperature of the gasification reactor 1 was 800 °C, the hydrogen production effect in the gasification reactor 1 was the best, and more hydrogen could be produced. This conclusion has been proven by the data of Comparative Examples 1-12 and Examples 1-8. Combining the data of Examples 9-20, it can be seen that when the temperature of the sorption-enhanced reactor 2 was set at 600 °C, the most hydrogen could be obtained through biomass gasification, and the hydrogen concentration value in the mixed gas was also the highest.

[0179] Because when the temperature in the gasification reactor 1 was set at a relatively high level, the gasification reaction could occur effectively, producing more hydrogen. At the same time, when the temperature in the sorption-enhanced reactor 2 was controlled to about 600 °C, the adsorption reaction occurred smoothly. In this sorption-enhanced reactor 2, carbon monoxide in the mixed gas reacted with water vapor to produce carbon dioxide, and these carbon dioxides, together with the carbon dioxide already present in the mixed gas, produced hydrogen through the adsorption of the adsorbent; when the adsorbent adsorbed carbon dioxide, it could also promote the reversible reaction in the gasification reactor 1 to move in the direction of hydrogen production, thus obtaining more hydrogen. It can be seen that in order to produce more hydrogen, the temperatures of the gasification reactor 1 and the sorption-enhanced reactor 2 need to be controlled separately.

[0180] Comparing the experimental data of Examples 9-20, it can be seen that when using a variety of biomasses with the same mass for hydrogen production, lignin has the best hydrogen production effect.

[0181] In a preferred embodiment of the present invention, in step S3, the reaction conditions include: the reaction temperature is 900 - 1200 °C, and the steam atmosphere is 40% - 60%.

[0182] In a preferred embodiment of the present invention, the adsorbent added in S2 is set as calcium hydroxide or calcium oxide;

[0183] In a preferred embodiment of the present invention, in S3, alumina is added to the regenerated adsorbent reactor.

[0184] In a preferred embodiment of the present invention, the mass ratio of alumina to the adsorbent is (0.3 - 0.5):1.

[0185] Therefore, in Examples 21 - 22, the optimal hydrogen production conditions are used: lignin as the raw material for biomass hydrogen production, and at the same time, the temperature of the gasification reactor 1 is controlled at 800 °C, and the temperature in the adsorption enhanced reactor 2 is 600 °C.

[0186] Example 21

[0187] (1) Weigh 1.382 g of lignin and add it to the gasification reactor 1. Input steam into the gasification reactor 1 at a rate of 70 mL / min, control the temperature of the gasification reactor 1 at 800 °C, and the pressure at 0.1 - 0.5 MPa to react to generate a mixed gas of hydrogen and carbon dioxide;

[0188] (2) Pass the mixed gas generated in step (1) into the adsorption enhanced reactor 2. Input steam into the adsorption enhanced reactor 2 at a rate of 70 mL / min. At the same time, weigh 3.251 g of calcium hydroxide as the adsorbent and add it to the adsorption enhanced reactor 2. Control the temperature in the adsorption enhanced reactor 2 at 600 °C. The calcium hydroxide absorbs carbon dioxide in the mixed gas to generate calcium carbonate, and collect the remaining mixed gas;

[0189] (3) Transport the calcium carbonate generated in step (1) to the regenerated adsorbent reactor 3. At the same time, input steam into the regenerated adsorbent reactor 3 at a rate of 70 mL / min. Control the temperature of the regenerated adsorbent reactor 3 at 950 °C. The calcium carbonate decomposes into calcium oxide, and the calcium oxide reacts with water vapor to be re - converted into calcium hydroxide with adsorption capacity, and send the calcium hydroxide back to the adsorption enhanced reactor 2 for recycling.

[0190] (4) While the calcium hydroxide is sent back to the adsorption enhanced reactor 2, weigh 1.382 g of lignin and add it to the gasification reactor 1.

[0191] Each time the calcium hydroxide returns is regarded as a cycle. From the start of the experiment to the first return of the calcium hydroxide, it is regarded as the first cycle stage. Between the first return and the second return of the calcium hydroxide is regarded as the second cycle stage, and so on.

[0192] The gas is collected in stages. In the first cycle stage, the hydrogen concentration can reach 77.77%, and the output is 641.41 mL; in the second cycle stage, the hydrogen concentration drops to 76.45%, and the output is 587.46 mL; in the third cycle stage, the hydrogen concentration is 65.46%, and the output is 561.31 mL; in the fourth cycle stage, the hydrogen concentration is 59.89%, and the output is 474.28 mL; in the fifth cycle stage, the hydrogen concentration is only 52.79%, and the output is 421.64 mL.

[0193] The experimental results of Example 21 are shown in Table 4:

[0194] Table 4

[0195]

[0196] Example 22

[0197] It is carried out according to the method of Example 1, except that while adding calcium hydroxide to the sorption enhanced reactor 2, a mixture of 1.398 g of alumina is added to the regenerated sorbent reactor 3.

[0198] The gas is collected in stages. In the first cycle stage, the hydrogen concentration can reach 78.47%, and the output is 644.86 mL; in the second cycle stage, the hydrogen concentration drops to 77.89%, and the output is 647.27 mL; in the third cycle stage, the hydrogen concentration is 79.52%, and the output is 638.21 mL; in the fourth cycle stage, the hydrogen concentration is 78.81%, and the output is 632.79 mL; in the fifth cycle stage, the hydrogen concentration is only 77.16%, and the output is 643.29 mL.

[0199] The experimental results of Example 22 are shown in Table 5:

[0200] Table 5

[0201] Item Concentration (%) Hydrogen production The first cycle 78.47 644.86 The second cycle 77.89 647.27 The third cycle 79.52 638.21 The fourth cycle 78.81 632.79 The fifth cycle 77.16 643.29

[0202] In Example 21, the repeated use of calcium hydroxide affects its adsorption effect. After calcium hydroxide is calcined once, the output of hydrogen detected in the second cycle stage shows a significant decrease, and the hydrogen concentration in the third cycle stage also shows a significant decrease. In the subsequent cycle stages, both the hydrogen output and the hydrogen concentration continue to decline. It can be seen that the cyclic use affects the adsorption performance of the sorbent.

[0203] It can be seen from the comparison between Example 22 and Example 21 that adding alumina to the regenerated sorbent reactor 3 can significantly improve the adsorption performance of calcium hydroxide during cyclic use.

[0204] SeeFigure 6 The XRD patterns of the adsorbent after five cycles are shown. Among them, the Ca(OH)₂ as-received curve represents the crystal structure characteristics of uncycled calcium hydroxide, the 5-Ca(OH)₂ curve represents the crystal structure characteristics of calcium hydroxide after the fifth cycle, and the Al₂O₃-5-Ca(OH)₂ curve represents the crystal structure characteristics of calcium hydroxide after adding alumina and the fifth cycle. It can be seen that the characteristic peaks of the crystal structure of uncycled calcium hydroxide are clear, indicating good crystallinity of calcium hydroxide; after the fifth cycle of calcium hydroxide, the characteristic peaks of residual calcium carbonate appear significantly enhanced, which means that there is unreacted calcium carbonate, affecting the regeneration purity of calcium hydroxide; when alumina is added to calcium hydroxide, after the fifth cycle, there are no characteristic peaks of residual calcium carbonate in the adsorbent, and a small amount of Ca(AlO₂)₂ is also found. Therefore, the presence of the new substance Ca(AlO₂)₂ may have a beneficial effect on the performance of the adsorbent.

[0205] See Figure 7 The SEM images of the adsorbent after five cycles are shown. (a) is the surface of calcium hydroxide in its original state, (b) is the surface of the adsorbent after the fifth cycle without adding alumina, and (c) is the surface of the adsorbent after the fifth cycle with adding alumina. It can be seen that when calcium hydroxide is not used as an adsorbent, the pore structure on its surface is evenly distributed, which is conducive to adsorption; after the fifth cycle, agglomeration begins to appear on the surface of regenerated calcium hydroxide, and the pore structure shrinks, which greatly reduces the specific surface area of the adsorbent, affects gas diffusion and adsorption efficiency, and significantly reduces its adsorption capacity; however, for calcium hydroxide with added alumina, after the fifth cycle, the surface still shows a uniform pore structure, indicating that its adsorption performance is maintained during the cycle. It can be seen that adding alumina alleviates the structural damage and performance degradation caused by sintering of the adsorbent to a certain extent, effectively ensuring the stable operation of the biomass gasification hydrogen production system and continuous hydrogen production.

[0206] Because a large amount of calcium carbonate is generated after calcium hydroxide adsorbs carbon dioxide for the first time. After these calcium carbonates are sent into the regenerated adsorbent reactor 3, through high-temperature calcination, calcium carbonate and alumina will generate a small amount of Ca(AlO₂)₂ and a large amount of calcium oxide at about 850 °C. When they encounter the water vapor in the regenerated adsorbent reactor 3, they will hydrolyze into a large amount of calcium hydroxide, a very small amount of aluminum hydroxide, and unhydrolyzed Ca(AlO₂)₂. From the perspective of structural stability, the formation of the new substance Ca(AlO₂)₂ may enhance the structural stability of the adsorbent, enabling it to maintain a relatively stable crystal structure after multiple cycles, so that the adsorbent after multiple cycles still has good adsorption performance.

[0207] In summary, during the repeated use of calcium hydroxide adsorbent, its crystal structure and surface morphology change, resulting in a decrease in its adsorption capacity. Therefore, the repeated use of calcium hydroxide adsorbent will affect the hydrogen production in biomass hydrogen production. However, adding alumina to the calcium hydroxide adsorbent can reliably solve the problem of easy caking during the cyclic use of calcium hydroxide, so that the adsorbent after multiple cycles still has good adsorption performance.

[0208] On the other hand, the present invention provides a two-stage and regenerated adsorbent hydrogen production device, which includes a gasification reactor 1, an adsorption-enhanced reactor 2, and a regenerated adsorbent reactor 3. The gasification reactor 1 and the adsorption-enhanced reactor 2 are connected through a gas pipe 4. A first conveying pipe 5 and a second conveying pipe 6 are arranged between the adsorption-enhanced reactor 2 and the regenerated adsorbent reactor 3, and the conveying directions in the first conveying pipe 5 and the second conveying pipe 6 are opposite;

[0209] The gasification reactor 1 is provided with a first feed port 11 and a first steam inlet 12. The adsorption-enhanced reactor 2 is provided with a hydrogen collection pipe 21, a third steam inlet 34, and a second feed port 23. The regenerated adsorbent reactor 3 is provided with a carbon dioxide collection pipe 31 and a second steam inlet 32.

[0210] The two-stage and regenerated adsorbent hydrogen production device provided by the present invention includes three reactors: a gasification reactor 1, an adsorption-enhanced reactor 2, and a regenerated adsorbent reactor 3. In the gasification reactor 1, biomass reacts with water vapor entering through the first steam inlet 12 to generate carbon dioxide and hydrogen. Subsequently, the mixed gas in the gasification reactor 1 enters the adsorption-enhanced reactor 2 through the gas pipe 4. In the adsorption-enhanced reactor 2, carbon dioxide in the mixed gas is adsorbed by the adsorbent to generate calcium carbonate and hydrogen.

[0211] In the adsorption-enhanced reactor 2, not only can hydrogen be generated through the reaction, but also carbon dioxide in the mixed gas can be consumed by the adsorbent, so that the hydrogen production reaction in the gasification reactor 1 connected to the adsorption-enhanced reactor 2 can be continuously promoted in the direction of hydrogen production.

[0212] The calcium carbonate generated after the reaction of the adsorbent with carbon dioxide is transported to the regenerated adsorbent reactor 3 through the first conveying pipe 5. In the high-temperature environment in the regenerated adsorbent reactor 3, calcium carbonate decomposes into calcium oxide and carbon dioxide. Subsequently, calcium oxide reacts with water vapor passing through the second steam inlet 32 to generate calcium hydroxide, and the calcium hydroxide is sent back to the adsorbent reactor through the first conveying pipe 5 for use as an adsorbent, thereby realizing the regeneration reaction of the adsorbent. Therefore, the two-stage and regenerated adsorbent hydrogen production device realizes the function of reusing the adsorbent by setting the regenerated adsorbent reactor 3.

[0213] Among them, the adsorbent can be pre-placed in the sorption-enhanced reactor 2 or added through the second feed port 23. To simplify the structure of the two-stage and regenerative adsorbent hydrogen production device, preferably, alumina can also be added through the second feed port 23. Since the adsorbent and alumina are hardly consumed during the biomass hydrogen production process, the adsorbent and alumina can be pre-placed in the sorption-enhanced reactor 2 and the regenerative adsorbent reactor 3 respectively.

[0214] The regenerative adsorbent reactor 3 is provided with a carbon dioxide collection pipe 31, through which the carbon dioxide in the regenerative adsorbent reactor 3 can be recovered.

[0215] The sorption-enhanced reactor 2 is provided with a hydrogen collection pipe 21, through which the hydrogen produced by the two-stage and regenerative adsorbent hydrogen production device can be collected.

[0216] Preferably, a continuously operating conveyor line is provided in the first conveyor pipe 5 and the second conveyor pipe 6, through which the transfer of solid substances between the sorption-enhanced reactor 2 and the regenerative adsorbent reactor 3 can be realized.

[0217] In a preferred embodiment of the present invention, the gasification reactor 1, the sorption-enhanced reactor 2, and the regenerative adsorbent reactor 3 are respectively provided with heating devices.

[0218] Through the heating devices, the reaction temperatures of the gasification reactor 1 and the sorption-enhanced reactor 2 can be controlled respectively. Therefore, by adjusting the heating devices in the gasification reactor 1 and the sorption-enhanced reactor 2 respectively, the maximum hydrogen production can be obtained.

[0219] Preferably, control valves 33 are respectively provided at the first steam inlet 12 and the second steam inlet 32. By adjusting the control valves 33, the flow rate of the steam introduced into the gasification reactor 1 and the sorption-enhanced reactor 2 can be controlled to meet the actual hydrogen production requirements.

[0220] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0221] In addition, it should be noted that among the various specific technical features described in the above specific embodiments, they can be combined in any appropriate manner without conflict. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

[0222] In addition, any combination can be made among various different embodiments of the present invention, as long as it does not violate the idea of the present invention, and it should equally be regarded as the content disclosed by the present invention.

Claims

1. A method for producing hydrogen from biomass, characterized in that, It includes the following steps: S1. Carry out a gasification reaction on biomass raw materials and water vapor in a gasification reactor (1) to generate a mixed gas; S2. React the mixed gas obtained in step S1 with water vapor and an adsorbent in an adsorption-enhanced reactor (2) to generate carbonate and collect hydrogen-rich gas; S3. React the carbonate obtained from the reaction in step S2 with water vapor in a regenerative adsorbent reactor (3), and the product obtained from the reaction enters the adsorption-enhanced reactor (2) for use as an adsorbent; Among them, the reaction pressure in the gasification reactor (1), the adsorption-enhanced reactor (2), and the regenerative adsorbent reactor (3) is 0.1 - 0.5 MPa.

2. The biomass hydrogen production method according to claim 1, characterized in that, In step S1, the conditions of the gasification reaction include: the temperature is 600 - 800 °C, and the water vapor atmosphere is 40% - 60%.

3. The biomass hydrogen production method according to claim 1, characterized in that, In step S2, the reaction conditions include: the reaction temperature is 500 - 700 °C, and the water vapor atmosphere is 40% - 60%.

4. The biomass hydrogen production method according to claim 1, wherein, In step S3, the reaction conditions include: the reaction temperature is 900 - 1200 °C, and the water vapor atmosphere is 55% - 60%.

5. The biomass hydrogen production method according to claim 3, wherein, The adsorbent added in S2 is calcium hydroxide or calcium oxide.

6. The biomass hydrogen production method according to claim 5, characterized in that, In S3, alumina is added to the regenerative adsorbent reactor.

7. The biomass hydrogen production method according to claim 6, characterized in that, The mass ratio of alumina to the adsorbent is (0.3 - 0.5):

1.

8. A two-stage hydrogen production device with a regenerable adsorbent, characterized in that, The two-stage and regenerative adsorbent hydrogen production device includes a gasification reactor (1), an adsorption-enhanced reactor (2), and a regenerative adsorbent reactor (3). The gasification reactor (1) and the adsorption-enhanced reactor (2) are connected by a gas pipe (4). A first transfer pipe (5) and a second transfer pipe (6) are arranged between the adsorption-enhanced reactor (2) and the regenerative adsorbent reactor (3), and the transfer directions in the first transfer pipe (5) and the second transfer pipe (6) are opposite; The gasification reactor (1) is provided with a first feed port (11) and a first steam inlet (12). The adsorption-enhanced reactor (2) is provided with a hydrogen collection pipe (21), a third steam inlet (34), and a second feed port (23). The regenerative adsorbent reactor (3) is provided with a carbon dioxide collection pipe (31) and a second steam inlet (32).

9. The two-stage and regenerative adsorbent hydrogen production device according to claim 8, characterized in that, The gasification reactor (1), the adsorption-enhanced reactor (2), and the regenerative adsorbent reactor (3) are respectively provided with heating devices.

Images