Regeneration method of alkali and catalyst in biomass hydrogen production system

Abstract

The invention relates to the field of biomass hydrogen production, and discloses a regeneration method of alkali and a catalyst in a biomass hydrogen production system, which comprises the following steps: (1) mixing a solid product obtained after a biomass alkali heat treatment hydrogen production reaction with water, dissolving, and separating to obtain a supernatant LA and a residue SA; (2) calcining the residue SA or the spent metal catalyst to obtain a regenerated metal catalyst; and (3) reacting the supernate LA with calcium oxide and / or calcium hydroxide, and filtering a product obtained by the reaction to obtain filtrate LB and filter residues SB. The method can realize mild recovery and regeneration of alkali and metal catalysts with high cost at the same time, and significantly reduces the cost of a biomass alkali heat treatment hydrogen production system.

Description

Technical Field

[0001] The invention relates to the technical field of biomass hydrogen production, and in particular to a method for regenerating an alkali and a catalyst in a biomass hydrogen production system. Background Art

[0002] Hydrogen energy has the characteristics of high mass energy density (120-142MJ / kg), wide production channels and no carbon emissions during use. It is considered to be the most promising secondary energy source and perfectly matches the trend of social development. However, currently more than 98% of the world's hydrogen energy comes from fossil resources. The high carbon emissions in the hydrogen production process and the increasing depletion of fossil energy have seriously damaged its economic and social value. Hydrogen derived from biomass with the characteristics of wide distribution, renewable and high yield is considered to be carbon neutral because plants use CO2 released as fuel during photosynthesis and almost no NO is produced. x and SO x Therefore, the full and reasonable use of biomass energy to produce hydrogen can alleviate the energy crisis and avoid a large amount of resource waste, and at the same time has positive environmental protection significance and good social benefits.

[0003] As a new type of thermal conversion technology, biomass alkali thermal treatment hydrogen production has the process characteristics of medium and low temperature range and normal pressure. It has a clear carbon (CO x ) capture and storage effect. From the perspective of the entire life cycle of biomass, this process has significant negative carbon emission advantages and the potential to replace fossil energy in the future, which fully conforms to the development concept of sustainable hydrogen production technology from renewable biomass with efficient CO2 capture and storage.

[0004] Zhao Ming et al. proposed a method and system for producing hydrogen by thermochemical reaction of sludge in patent application CN108130346A. The method is simple to operate and can effectively remove greenhouse gases such as CO2 produced during the thermal treatment of sludge. However, the tar produced during the reaction and the CH4 present in the product gas significantly reduce the grade of hydrogen, and the lack of further utilization of solid products hinders the maximization of the economic value of the entire system. Hu Zhiquan et al. used a bifunctional calcium-based catalyst in patent application CN113845087A to further enhance the yield of hydrogen produced by co-catalytic gasification of biomass and sludge.

[0005] At present, the biomass alkali thermal treatment hydrogen production system with a high hydrogen production yield is composed of biomass raw materials (B), alkali (alkali metal hydroxide) (A), nickel-based supported metal catalyst (C) and trace water, including a reaction system in which the three are directly mixed (B+A+C) and a reaction system in which the catalyst is placed in steps ((B+A)+C). With the participation of the catalyst, the system can significantly reduce the content of gas by-products and improve the hydrogen production yield and purity. The reference is "Investigation of the role of Ca(OH)2in the catalytic Alkaline Thermal Treatment of cellulose to produce H2with integrated carbon capture" Journal of Energy Chemistry, 2017(5):17,984-1000.DOI:10.1016 / j.jechem.2017.07.013. However, the high cost caused by the large-scale use of alkali and metal catalysts has seriously restricted the development and application of the above-mentioned biomass alkali thermal treatment hydrogen production system. In particular, although the direct mixing reaction process can maximize the hydrogen production from biomass alkali thermal treatment, the lower melting point of alkali metal hydroxides causes them to develop into a molten state during the reaction, which in turn causes serious pore blockage of the metal catalyst and further leads to catalyst coking, carbon deposition, etc., and the final solid product exists as a dense solid substance. In addition, the instability of alkali metal carbonates may undermine the value of "negative carbon emissions". The advantages of known biomass alkali thermal treatment are low temperature, normal pressure, high purity of hydrogen production, negative carbon emission process, and the main component of the solid product is alkali metal carbonate with higher added value. Therefore, the reasonable recovery and regeneration of alkali and metal catalysts in biomass alkali thermal treatment systems of different processes can significantly reduce the cost of hydrogen production reactions and improve system utilization. To date, there have been no research reports and related technologies on the simultaneous mild recovery and regeneration of the above-mentioned alkali and metal catalysts. Summary of the invention

[0006] The purpose of the present invention is to achieve simultaneous recovery and regeneration of alkali and metal catalysts in a biomass alkali thermal treatment hydrogen production system, and to provide a method for regenerating alkali and catalysts in a biomass hydrogen production system. The method can achieve simultaneous and gentle recovery and regeneration of relatively high-cost alkali and metal catalysts, thereby significantly reducing the cost of the biomass alkali thermal treatment hydrogen production system.

[0007] In order to achieve the above object, the present invention provides a method for regenerating an alkali and a catalyst in a biomass hydrogen production system, the method comprising the following steps:

[0008] (1) Mix the solid product after the biomass alkali heat treatment hydrogen production reaction with water to dissolve it, and separate the supernatant LA and residue S A ;

[0009] (2) The residue S A or calcining the spent metal catalyst to obtain a regenerated metal catalyst;

[0010] (3) The supernatant L A react with calcium oxide and / or calcium hydroxide, and filter the product obtained by the reaction to obtain a filtrate L B and filter residue S B .

[0011] Preferably, the calcium hydroxide is provided by electroslag and / or steel slag.

[0012] Through the above technical scheme, for the first time, the simultaneous mild recovery and regeneration of high-cost alkali and metal catalysts are achieved, and the regenerated alkali and regenerated metal catalysts can be directly recycled, which significantly reduces the cost of the biomass alkali thermal treatment hydrogen production system and improves the system utilization rate; the method is simple in process and mild in conditions, has a high recovery rate of alkali and metal catalysts, and the catalytic performance of the metal catalyst is maintained well. Among them, calcium hydroxide can not only be selected as pure substances but also industrial solid waste (such as electroslag, steel slag and other substances containing calcium hydroxide and active calcium oxide components), and the calcium carbonate in the product retains the inherent negative carbon emission characteristics of the biomass alkali thermal treatment hydrogen production system due to its insolubility and high stability. After separation again, it can be further commercialized, and the overall process has significant economic, environmental and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a flow chart of the method of the present invention;

[0014] Figure 2 is the XRD spectrum of the fresh catalyst and the metal catalyst after regeneration in Example 1, the main component is 10wt% NiO / ZrO2;

[0015] Figure 3 is the XRD spectrum of the regenerated calcium carbonate in Example 1;

[0016] Figure 4 The hydrogen production under the same reaction conditions using the base and catalyst before and after regeneration in Example 1. DETAILED DESCRIPTION

[0017] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise 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, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0018] The present invention provides a method for regenerating an alkali and a catalyst in a biomass hydrogen production system, the method comprising the following steps:

[0019] (1) Mix the solid product after the biomass alkali heat treatment hydrogen production reaction with water to dissolve it, and separate the supernatant L A and residue S A ;

[0020] (2) The residue S A or calcining the spent metal catalyst to obtain a regenerated metal catalyst;

[0021] (3) The supernatant L A react with calcium oxide and / or calcium hydroxide, and filter the product obtained by the reaction to obtain a filtrate L B and filter residue S B .

[0022] According to the present invention, in order to further improve the recovery effect, preferably, the method further comprises crushing the solid product and then mixing it with water. There is no particular limitation on the specific operation of crushing, and those skilled in the art can make an adaptive choice according to the actual situation.

[0023] According to a preferred embodiment of the present invention, in step (1), the mass ratio of the solid product to water is 1:5-30, preferably 1:10-20, for example, 1:10, 1:12, 1:14, 1:16, 1:18 or 1:20.

[0024] According to the present invention, preferably, the dissolution is performed under ultrasound-assisted conditions.

[0025] According to the present invention, preferably, the dissolution conditions include: temperature of 40-60°C, time of 30-60 min, more preferably, temperature of 40-50°C, time of 30-40 min.

[0026] According to the present invention, preferably, the mixing and dissolving are repeated more than once. Those skilled in the art can make appropriate selections according to the dissolution of the alkali metal carbonate in the solid product. Considering the ease of operation and dissolution effect, the mixing and dissolving are preferably repeated 2-3 times.

[0027] According to a preferred embodiment of the present invention, the solid product in step (1) is mixed with water and then subjected to ultrasound-assisted dissolution. The process of adding water, mixing and dissolving can be repeated to further dissolve the alkali metal carbonate in the solid product in water. The supernatant L is obtained by separation. A .

[0028] According to the present invention, preferably, the separation is centrifugal separation. Solid-liquid phase separation can be achieved by centrifugation.

[0029] Preferably, the method further comprises washing the remaining solid with a small amount of deionized water until the filtrate is neutral.

[0030] According to the present invention, L A The main components are alkali metal carbonates, S A The main components are metal catalysts, coking products and trace ash contained in biomass.

[0031] According to the present invention, preferably, in step (2), the calcination conditions include: temperature of 400-600°C, time of 2-6h, more preferably, temperature of 400-500°C, time of 2.5-3h.

[0032] The drying and calcining in step (2) of the present invention can remove the coke in the regenerated catalyst, thereby obtaining a regenerated metal catalyst.

[0033] According to the present invention, preferably, the method further comprises reducing the catalyst obtained by calcining in step (2); the reduction conditions include: in a hydrogen-containing atmosphere, a temperature of 500-700° C., and a time of 2-4 hours. The calcined catalyst can be reused by further reducing it in a hydrogen atmosphere. The hydrogen-containing atmosphere can be provided by a gas containing hydrogen, preferably pure hydrogen. The present invention has no particular limitation on the pressure of the reduction, for example, it can be normal pressure.

[0034] According to the present invention, in step (3), the supernatant L A Calcium oxide may be added to the reaction, or calcium hydroxide may be added to the reaction. The present invention has no particular limitation on this, as long as the alkali metal carbonate can be converted into an alkali metal hydroxide.

[0035] The reaction in step (3) can be carried out according to the supernatant L A The amount of water in the reaction can be determined by considering whether additional water is added to facilitate the reaction. In step (3), water can be optionally added to convert calcium oxide into calcium hydroxide.

[0036] Preferably, in step (3), the supernatant L A The reaction is carried out with calcium hydroxide, which is provided in the form of a calcium hydroxide solution.

[0037] In the present invention, calcium oxide and / or calcium hydroxide can be selected from pure substances or industrial solid waste. The type of industrial solid waste can be selected from a wide range, as long as it contains calcium oxide and / or calcium hydroxide, such as electroslag, steel slag and other substances containing calcium hydroxide and active calcium oxide components. Preferably, the calcium oxide and / or calcium hydroxide are provided by electroslag and / or steel slag. By adopting this preferred embodiment, not only can the catalyst and alkali in the biomass alkali heat treatment hydrogen production reaction system be gently recovered, but also industrial solid waste can be treated, which has significant economic, environmental and social benefits.

[0038] According to a preferred embodiment of the present invention, in the electroslag, the total content of calcium hydroxide and calcium oxide is about 70-73% by weight, and the content of calcium hydroxide is about 12-15% by weight.

[0039] Preferably, the molar ratio of the amount of calcium oxide and / or calcium hydroxide or the amount of industrial solid waste calculated as calcium to the alkali metal carbonate in the solid product is 1.5-2.5: 1. Calcium hydroxide can be slightly excessive due to its low solubility.

[0040] According to the present invention, the reaction in step (3) can be carried out once or multiple times. Preferably, when the reaction is carried out twice or more, preferably after each reaction, centrifugation is performed to obtain a supernatant, and then calcium oxide and / or calcium hydroxide is added to the supernatant to carry out the next reaction.

[0041] According to the present invention, there is no particular limitation on the source of the solid product after the biomass alkali heat treatment hydrogen production reaction in step (1), and it can be any solid product recovered from the biomass alkali heat treatment hydrogen production system in the art. The solid product only needs to come from the biomass alkali heat treatment hydrogen production system consisting of three parts: biomass raw material (B), alkali (A) and metal catalyst (C), which can include a reaction system (B+A+C) in which the three are directly mixed, or a reaction system ((B+A)+C) in which the catalyst is placed in steps. In the reaction system (B+A+C) in which the three are directly mixed, the residue S obtained in step (1) A The main component of the catalyst is the metal catalyst to be regenerated, which can be calcined in step (2) to obtain the regenerated metal catalyst. Preferably, before the calcination, the residue S A Drying is performed, and there is no particular limitation on the drying conditions. For example, the drying conditions include: a temperature of 100-110° C. and a time of 2.5-3 h. In the reaction system ((B+A)+C) in which the catalyst is placed step by step, the metal catalyst is placed separately from the biomass and the alkali metal hydroxide, and the solid product does not include the metal catalyst to be produced, but only includes a small amount of residual carbon. In this embodiment, in step (2) of the present invention, the metal catalyst to be produced is calcined separately, and the residue S obtained in step (1) isA Can be discharged directly from the system.

[0042] According to the present invention, preferably, the solid product of step (1) includes a biomass alkali thermal treatment hydrogen production reaction derived from direct mixing of biomass raw materials, alkali and metal catalyst; or a biomass alkali thermal treatment hydrogen production reaction derived from stepwise placement of metal catalyst, biomass raw materials and alkali.

[0043] According to a preferred embodiment of the present invention, the solid product of step (1) includes a biomass alkali heat treatment hydrogen production reaction obtained by directly mixing a biomass raw material, an alkali and a metal catalyst, and the solid product of step (1) includes: an alkali metal carbonate, an alkali metal hydroxide (unreacted in the hydrogen production reaction) and a metal catalyst to be produced including insoluble carbon residue; more preferably, based on the total amount of the solid product, the content of the alkali metal carbonate is 50-60% by weight, the content of the alkali metal hydroxide is 10-25% by weight, and the content of the metal catalyst to be produced is 15-40% by weight.

[0044] According to another preferred embodiment of the present invention, the solid product of step (1) includes a biomass alkali heat treatment hydrogen production reaction in which a metal catalyst is placed in steps with a biomass raw material and an alkali metal hydroxide; the solid product of step (1) includes: an alkali metal carbonate, an alkali metal hydroxide (unreacted in the hydrogen production reaction) and a residual carbon; more preferably, based on the total amount of the solid product, the content of the alkali metal carbonate is 70-80% by weight, the content of the alkali metal hydroxide is 10-15% by weight, and the content of the residual carbon is 5-15% by weight.

[0045] According to the present invention, preferably, the coke content is 5-15 wt % based on the total amount of the spent metal catalyst.

[0046] According to the present invention, preferably, the alkali metal carbonate is at least one of sodium carbonate, potassium carbonate and rubidium carbonate.

[0047] The present invention has no particular limitation on the types of biomass raw materials, alkali metal hydroxides and metal catalysts, which may be any conventional materials in the art that can be used in a biomass alkali thermal treatment hydrogen production system.

[0048] Preferably, the biomass raw material includes real biomass and / or model biomass separated from real biomass. Preferably, the real biomass includes at least one of Chinese medicine residues, bamboo residues, wood residues and straw; preferably, the model biomass includes at least one of glucose, cellulose, hemicellulose, xylose and lignin. In the embodiments of the present invention, Chinese medicine residues and glucose are used as examples for exemplary description, but the present invention is not limited thereto.

[0049] Preferably, the base is an alkali metal hydroxide, more preferably at least one of NaOH, KOH and RbOH.

[0050] According to the present invention, specifically, the metal catalyst comprises a carrier and an active component. Preferably, the catalyst is a nickel-based supported oxide catalyst.

[0051] According to a preferred embodiment of the present invention, the carrier is zirconium oxide and / or cerium oxide, and the active component is Ni.

[0052] According to the present invention, preferably, based on the total amount of the metal catalyst, the content of the active component is 5-15% by weight in terms of oxide.

[0053] In the present invention, there is no particular limitation on the reaction conditions in the biomass alkali heat treatment hydrogen production reaction and the amounts of biomass raw materials, alkali and metal catalysts, and those skilled in the art can select them according to conventional technical means in the art.

[0054] According to the present invention, preferably, the amount of calcium oxide and / or calcium hydroxide used in step (3) is 65-75% of the molar amount of the alkali metal hydroxide in the hydrogen production reaction, for example, 65%, 68%, 70%, 72% or 75%.

[0055] According to the present invention, preferably, the calcium oxide and / or calcium hydroxide is provided by electroslag, and the added amount of the electroslag is 3-4 times the mass of the alkali metal hydroxide.

[0056] According to a preferred embodiment of the present invention, the method further comprises: B The vacuum drying is performed to obtain calcium carbonate as a byproduct. The present invention has no particular limitation on the vacuum drying conditions, and those skilled in the art can make appropriate selections according to actual conditions to obtain calcium carbonate as a byproduct.

[0057] According to the present invention, preferably, the method further comprises: B The washing is then performed and then the vacuum drying is performed. The washing can be performed according to conventional techniques in the art, and the washing agent can be water (eg, deionized water). The washing is preferably performed until the filtrate is neutral.

[0058] According to a preferred embodiment of the present invention, the method further comprises: B The product is optionally concentrated and recycled to provide at least a portion of the raw alkali (alkali metal hydroxide) in the hydrogen production reaction by alkali thermal treatment of biomass.

[0059] In the present invention, the filtrate L is recovered. BThe alkali metal hydroxides in the sample can be qualitatively and quantitatively determined using 0.1 mol / L HCl solution. The reference standard is "Industrial Sodium Hydroxide - Determination of Sodium Hydroxide and Sodium Carbonate Content, Standard No.: GB / T4348.1-2013".

[0060] The present invention will be described in detail below through examples.

[0061] Example 1

[0062] This example is used to illustrate the recovery and regeneration of alkali metal hydroxide (NaOH) and metal catalyst (10wt% Ni / ZrO2) in the glucose alkali heat treatment hydrogen production system.

[0063] (1) Figure 1 As shown, in the first hydrogen production reaction, the addition amounts of glucose, NaOH and 10wt% Ni / ZrO2 were 185.6mg, 482.1mg and 167.9mg respectively, and the hydrogen production after alkaline heat treatment was 52.49mmol / g glucose. The reaction conditions were heating from 110℃ to 600℃ at a constant heating rate of 5℃ / min and keeping the temperature constant for 30min. A small amount (507.5mg) of the solid crude product (wherein the alkali metal carbonate content was about 53wt%, the unreacted alkali metal hydroxide was about 13wt% and the catalyst to be produced was about 34wt% (wherein the coke content was about 7wt%)) was transferred to an agate mortar and fully ground, 10mL of deionized water was measured and ultrasonically assisted to fully dissolve the solid at 50℃, and then the solid-liquid phase was separated by centrifugation, and the reaction was repeated twice. The remaining solid was washed with a small amount of deionized water for several times until the filtrate was neutral to obtain the filter residue S A and filtrate L A .

[0064] (2) S A Place it in an oven and dry it at 110°C to remove water for 3 hours. The dried sample is placed in a tubular furnace and calcined in an air atmosphere at 500°C for 3 hours to obtain 126.3 mg of regenerated NiO / ZrO2 and store it for later use. The catalyst regeneration rate Y is 92.2% (the calculation method is shown in formulas ①-②, the same below, where 27% is the mass percentage of the solid crude product excluding coke). Before use, the solid particles are reduced at 500°C, pure H2 and normal pressure atmosphere for 2 hours to obtain regenerated 10wt% Ni / ZrO2.

[0065] Y 催化剂 %=(M 再生催化剂 / M 新鲜催化剂 )×100% ①

[0066] M 新鲜催化剂 =M 固体粗产物 ×27% ②

[0067] (3) Take 417.4 mg of pure calcium hydroxide and dissolve it in 10 mL of deionized water. A Add while stirring, let stand for 30 minutes, centrifuge to separate the supernatant, repeatedly add the same mass of calcium hydroxide to the supernatant to react, then collect the solution to obtain the filter residue S B and filtrate L B (NaOH solution), wash the filter residue with deionized water until the filtrate is neutral, and treat the filtrate with 0.1271 mol / L HCl solution. B Qualitative and quantitative analysis yielded 318.0 mg of regenerated NaOH, with an alkali regeneration rate Y of 98.27% (the calculation method is shown in the following formula, the same below, where 66% is the total alkali content (sodium carbonate + sodium hydroxide) in the solid crude product, M 剩余Na2CO3 It refers to the sodium carbonate (a small amount) that has not been reacted with calcium hydroxide after the regeneration reaction.

[0068] Y 碱 %=(M 再生碱 / M 新鲜碱 )×100% ③

[0069] M 新鲜碱 =(M 固体粗产物 ×66%)-M 剩余Na2CO3 ④

[0070] (4) Vacuum drying the filter residue S at the same time B and concentrated filtrate L B The latter was used for the biomass alkali heat treatment hydrogen production cycle experiment. 488.1 mg of the regenerated alkali in step (3) and 167.9 mg of the regenerated catalyst in step (2) were used for repeated experiments (the amount of glucose added was 183.4 mg). The reaction conditions were the same as the initial reaction, and the hydrogen production was 46.34 mmol / g glucose, which had good reproducibility.

[0071] Figure 2 XRD spectra of fresh catalyst and regenerated 10wt% Ni / ZrO2 obtained in step (2).

[0072] Figure 3 The vacuum drying residue S of step (4) B XRD spectrum of the obtained regenerated calcium carbonate.

[0073] Figure 4 The hydrogen production under the same reaction conditions using the base and catalyst before and after regeneration in Example 1.

[0074] Example 2

[0075] This example is used to illustrate the recovery and regeneration of alkali metal hydroxide (NaOH) and metal catalyst (10wt% Ni / ZrO2) in the hydrogen production system by alkali-heat treatment of traditional Chinese medicine residues.

[0076] (1) In the first hydrogen production reaction, the addition amounts of Chinese medicine residue, NaOH and 10wt% Ni / ZrO2 were 184.1mg, 545.6mg and 184.1mg respectively, and the hydrogen production after alkali heat treatment was 43.74mmol / g Chinese medicine residue, and the reaction conditions were the same as those in Example 1. A small amount (475.6mg) of the solid crude product (wherein the alkali metal carbonate content was about 55wt%, the unreacted alkali metal hydroxide content was about 15wt% and the catalyst to be produced was about 30wt% (wherein the coke content was about 5wt%)) was transferred to an agate mortar and fully ground, 9mL of deionized water was measured and ultrasonically assisted to fully dissolve the solid at 50°C, and then the solid-liquid phase was separated by centrifugation, and the process was repeated twice, and the remaining solid was washed with a small amount of deionized water for several times until the filtrate was neutral to obtain a filter residue S. A and filtrate L A .

[0077] (2)S A The recovery and regeneration were the same as in step (2) of Example 1, and the catalyst regeneration rate was 93.96%.

[0078] (3) Take 409.2 mg of pure calcium hydroxide and dissolve it in 10 mL of deionized water. A Add while stirring, let stand for 30 minutes, centrifuge to separate the supernatant, repeatedly add the same mass of calcium hydroxide to the supernatant to react, then collect the solution to obtain the filter residue S B and filtrate L B (NaOH solution), wash the filter residue with deionized water until the filtrate is neutral, and treat the filtrate with 0.1271 mol / L HCl solution. B Qualitative and quantitative analysis yielded 321.8 mg of regenerated NaOH, with an alkali regeneration rate of 96.96%.

[0079] (4) Vacuum drying the filter residue S at the same time B and concentrated filtrate L B The latter was used for the biomass alkali heat treatment hydrogen production cycle experiment. 548.0 mg of the regenerated alkali in step (3) and 185.7 mg of the regenerated catalyst in step (2) were taken to repeat the experiment (the amount of Chinese medicine residue added was 185.0 mg). The reaction conditions were the same as the initial reaction, and the hydrogen production yield was 42.67 mmol / g of Chinese medicine residue, which had good reproducibility.

[0080] Example 3

[0081] This example is used to illustrate the recovery and regeneration of alkali metal hydroxide (KOH) and metal catalyst (10wt% Ni / CeO2) in the glucose alkali heat treatment hydrogen production system.

[0082] (1) In the first hydrogen production reaction, the addition amounts of glucose, KOH and 10wt% Ni / CeO2 were 182.7mg, 677.0mg and 213.0mg respectively, and the hydrogen production after alkali heat treatment was 54.39mmol / g glucose, and the reaction conditions were the same as those in Example 1. A small amount (425.2mg) of the solid crude product (wherein the alkali metal carbonate content was about 60wt%, the unreacted alkali metal hydroxide content was about 13wt% and the catalyst to be produced was about 27wt% (wherein the coke content was about 2wt%)) was transferred to an agate mortar and fully ground, 8mL of deionized water was measured and ultrasonically assisted to fully dissolve the solid at 50°C, and then the solid-liquid phase was separated by centrifugation, and the process was repeated twice, and the remaining solid was washed with a small amount of deionized water for several times until the filtrate was neutral to obtain a filter residue S. A and filtrate L A .

[0083] (2)S A The recovery and regeneration were the same as in step (2) of Example 1, and 105.8 mg NiO / CeO2 was obtained and stored for later use. The catalyst regeneration rate was 98.05%.

[0084] (3) Take 354.6 mg of carbide slag (calcium hydroxide content of 15% by weight, calcium oxide content of 58% by weight), dissolve it in 10 mL of deionized water, and add the filtrate L A Add while stirring, let stand for 30 minutes, centrifuge to separate the supernatant, repeatedly add the same mass of carbide slag to the supernatant to react, then collect the solution to obtain the filter residue S B and filtrate L B (KOH solution), wash the filter residue with deionized water until the filtrate is neutral, and treat the filtrate with 0.1271 mol / L HCl solution. B Qualitative and quantitative analysis yielded 324.5 mg of regenerated KOH, with an alkali regeneration rate of 89.95%.

[0085] (4) Vacuum drying the filter residue S at the same time B and concentrated filtrate L B The latter was used for the biomass alkali heat treatment hydrogen production cycle experiment. 678.2 mg of the regenerated alkali in step (3) and 213.9 mg of the regenerated catalyst in step (2) were used for repeated experiments (the amount of glucose added was 184.2 mg). The reaction conditions were the same as the initial reaction, and the hydrogen production was 50.77 mmol / g glucose, which had good reproducibility.

[0086] Example 4

[0087] This example is used to illustrate the recovery and regeneration of alkali metal hydroxide (KOH) and metal catalyst (10wt% Ni / CeO2) in the hydrogen production system by alkali-heat treatment of traditional Chinese medicine residues.

[0088] (1) In the first hydrogen production reaction, the addition amounts of Chinese medicine residue, KOH and 10wt% Ni / CeO2 were 184.0 mg, 542.1 mg and 185.7 mg respectively, and the hydrogen production after alkali heat treatment was 55.10 mmol / g Chinese medicine residue, and the reaction conditions were the same as those in Example 1. A small amount (452.2 mg) of the solid crude product (wherein the alkali metal carbonate content was about 60 wt%, the unreacted alkali metal hydroxide content was about 15 wt% and the catalyst to be produced was about 25 wt% (wherein the coke content was about 3 wt%)) was transferred to an agate mortar and fully ground, 10 mL of deionized water was measured and ultrasonically assisted to fully dissolve the solid at 50°C, and then the solid-liquid phase was separated by centrifugation, and the process was repeated twice, and the remaining solid was washed with a small amount of deionized water for several times until the filtrate was neutral to obtain a filter residue S. A and filtrate L A .

[0089] (2)S A The recovery and regeneration were the same as in step (2) of Example 1, and 102.4 mg NiO / CeO2 was obtained and stored for later use. The catalyst regeneration rate was 89.20%.

[0090] (3) Take 377.3 mg of carbide slag (with a molar ratio of 2.5 to sodium carbonate, a calcium hydroxide content of 15% by weight, and a calcium oxide content of 58% by weight) and dissolve it in 10 mL of deionized water. A Add while stirring, let stand for 30 minutes, centrifuge to separate the supernatant, repeatedly add the same mass of carbide slag to the supernatant to react, then collect the solution to obtain the filter residue S B and filtrate L B (KOH solution), wash the filter residue with deionized water until the filtrate is neutral, and treat the filtrate with 0.1271 mol / L HCl solution. B Qualitative and quantitative analysis revealed 345.9 mg of regenerated KOH, with an alkali regeneration rate of 92.54%.

[0091] (4) Vacuum drying the filter residue S at the same time B and concentrated filtrate L B The latter was used for the biomass alkali heat treatment hydrogen production cycle experiment. 545.5 mg of the regenerated alkali in step (3) and 187.7 mg of the regenerated catalyst in step (2) were taken to repeat the experiment (the amount of Chinese medicine residue added was 185.1 mg). The reaction conditions were the same as the initial reaction, and the hydrogen production yield was 58.59 mmol / g of Chinese medicine residue, which had good reproducibility.

[0092] Example 5

[0093] This example is used to illustrate the recovery and regeneration of alkali metal hydroxide (NaOH) and metal catalyst (10wt% Ni / ZrO2) in the glucose alkali heat treatment hydrogen production system under a step-by-step reaction system ((B+A)+C).

[0094] (1) In the first hydrogen production reaction, the addition amounts of glucose, NaOH and 10wt% Ni / ZrO2 were 182.5mg, 485.6mg and 168.2mg respectively, and the hydrogen production after alkali heat treatment was 22.86mmol / g glucose, and the reaction conditions were the same as those in Example 1. All (520.1mg) of the solid crude product (containing about 75wt% of alkali metal carbonate, about 15wt% of unreacted alkali metal hydroxide and about 10wt% of residual carbon, excluding metal catalyst) were transferred to an agate mortar and fully ground, 10mL of deionized water was measured and ultrasonically assisted to fully dissolve the solid at 50°C, and then the solid-liquid phase was separated by centrifugation, and the process was repeated twice. The remaining solid was washed with a small amount of deionized water for several times until the filtrate was neutral to obtain a filter residue S. A and filtrate L A .

[0095] (2) 168.2 mg of the spent metal catalyst obtained by the hydrogen production reaction was regenerated. The regeneration conditions of the spent metal catalyst were the same as those in step (2) of Example 1. 158.5 mg of NiO / ZrO2 was regenerated and stored for later use. The catalyst regeneration rate Y was 94.23%. The calculation method is shown in reaction formula ⑤.

[0096] Y 催化剂 % =(M 再生催化剂 / M 新鲜催化剂 )× 100% ⑤

[0097] (3) Take 577.2 mg of pure calcium hydroxide and dissolve it in 10 mL of deionized water. A Add while stirring, let stand for 30 minutes, centrifuge to separate the supernatant, repeatedly add the same mass of calcium hydroxide to the supernatant to react, then collect the solution to obtain the filter residue S B and filtrate L B (NaOH solution), wash the filter residue with deionized water until the filtrate is neutral, and treat the filtrate with 0.1271 mol / L HCl solution. B Qualitative and quantitative analysis yielded 464.1 mg of regenerated NaOH, with an alkali regeneration rate of 95.59%. The calculation method is shown in reaction formula ⑥.

[0098] Y 碱 % =(M 再生碱 / M 新鲜碱 )× 100% ⑥

[0099] (4) Vacuum drying the filter residue S at the same time B and concentrated filtrate L B The latter was used for the biomass alkali heat treatment hydrogen production cycle experiment. 483.7 mg of the regenerated alkali in step (3) and 169.3 mg of the regenerated catalyst in step (2) were taken to repeat the experiment (the amount of glucose added was 186.4 mg). The reaction conditions were the same as the initial reaction, and the hydrogen production was 22.93 mmol / g glucose, which had good reproducibility.

[0100] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for regenerating an alkali and a catalyst in a biomass hydrogen production system, characterized in that: The method comprises the following steps: (1) Mix the solid product after the biomass alkali heat treatment hydrogen production reaction with water to dissolve it, and separate the supernatant L A and residue S A ; (2) The residue S A or calcining the spent metal catalyst to obtain a regenerated metal catalyst; (3) The supernatant L A react with calcium oxide and / or calcium hydroxide, and filter the product obtained by the reaction to obtain a filtrate L B and filter residue S B .

2. The regeneration method according to claim 1, wherein: In step (1), the mass ratio of the solid product to water is 1:5-30, preferably 1:10-20; Preferably, the dissolution is performed under ultrasound-assisted conditions; Preferably, the dissolution conditions include: temperature of 40-60°C and time of 30-60min; Preferably, the mixing and dissolving are performed more than once, preferably 2-3 times.

3. The regeneration method according to claim 1 or 2, wherein: In step (2), the calcination conditions include: temperature of 400-600° C. and time of 2-6 hours.

4. The regeneration method according to any one of claims 1 to 3, wherein: The method further comprises reducing the catalyst obtained by calcining in step (2); The reduction conditions include: in a hydrogen-containing atmosphere, a temperature of 500-700° C., and a time of 2-4 hours.

5. The regeneration method according to any one of claims 1 to 4, wherein: In step (3), the supernatant L A reacting with calcium hydroxide, wherein the calcium hydroxide is provided in the form of a calcium hydroxide solution; Preferably, the calcium oxide and / or calcium hydroxide is provided by electroslag and / or steel slag; Preferably, the molar ratio of the amount of calcium oxide and / or calcium hydroxide or the amount of industrial solid waste calculated as calcium to the alkali metal carbonate in the solid product is 1.5-2.5:

1.

6. The regeneration method according to any one of claims 1 to 5, wherein: The solid product of step (1) includes a biomass alkali heat treatment hydrogen production reaction from a direct mixture of biomass raw materials, alkali metal hydroxides and metal catalysts; or a biomass alkali heat treatment hydrogen production reaction from a stepwise placement of metal catalysts, biomass raw materials and alkali metal hydroxides.

7. The regeneration method according to claim 6, wherein: The solid product of step (1) includes a biomass alkali heat treatment hydrogen production reaction directly mixing a biomass raw material, an alkali metal hydroxide and a metal catalyst; The solid product of step (1) comprises: alkali metal carbonate, alkali metal hydroxide and a metal catalyst to be produced including insoluble carbon residue; Preferably, based on the total amount of the solid product, the content of alkali metal carbonate is 50-60% by weight, the content of alkali metal hydroxide is 10-25% by weight, and the content of the spent metal catalyst is 15-40% by weight; Preferably, the coke content is 5-15 wt % based on the total amount of the spent metal catalyst.

8. The regeneration method according to claim 6, wherein: The solid product of step (1) includes a biomass alkali heat treatment hydrogen production reaction in which a metal catalyst is placed step by step with a biomass raw material and an alkali metal hydroxide; The solid product of step (1) includes: alkali metal carbonate, alkali metal hydroxide and carbon residue; Preferably, based on the total amount of the solid product, the content of alkali metal carbonate is 70-80% by weight, the content of unreacted alkali metal hydroxide is 10-15% by weight, and the content of residual carbon is 5-15% by weight.

9. The regeneration method according to claim 7 or 8, wherein: The alkali metal carbonate is at least one of sodium carbonate, potassium carbonate and rubidium carbonate; and / or, the alkali metal hydroxide is at least one of NaOH, KOH and RbOH; And / or, the metal catalyst comprises a carrier and an active component, the carrier is zirconium oxide and / or cerium oxide, and the active component is Ni; preferably, based on the total amount of the metal catalyst, the content of the active component is 5-15% by weight in terms of oxide.

10. The regeneration method according to any one of claims 6 to 9, wherein: The biomass raw material includes real biomass and / or model biomass separated from real biomass; Preferably, the real biomass includes at least one of Chinese medicine residues, bamboo residues, wood residues and straw; Preferably, the model biomass comprises at least one of glucose, cellulose, hemicellulose, xylose and lignin.

11. The regeneration method according to any one of claims 1 to 10, wherein: The method further includes: The filter residue S B Perform vacuum drying to obtain calcium carbonate as a by-product; And / or, the filtrate L B The product is optionally concentrated and recycled to provide at least part of the raw alkali for the hydrogen production reaction by alkali thermal treatment of biomass.

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