Equipment for preparing hydrogen from biomass, method for preparing hydrogen from biomass and application

Abstract

The invention relates to the technical field of hydrogen production, in particular to equipment for preparing hydrogen from biomass, a method for preparing hydrogen from biomass and application. The equipment comprises a biomass pretreatment system and a chemical-looping hydrogen production system, wherein the biomass pretreatment system comprises a drying unit, a crushing unit and a granulating unit; the chemical-looping hydrogen production system comprises a biomass hydrogen production reduction reactor, a hydrogen purification device and a dust remover; the dust remover is connected with a regeneration storage tank and an air oxidation reactor; the air oxidation reactor is connected with the biomass hydrogen production reduction reactor; the granulating unit is connected with the biomass hydrogen production reduction reactor; a first heat exchanger is arranged between a synthesis gas outlet of the biomass hydrogen production reduction reactor and the hydrogen purification device, and a water vapor outlet of the first heat exchanger is connected with the biomass hydrogen production reduction reactor; and an oxygen-poor waste gas outlet of the air oxidation reactor is connected with the drying unit. The equipment is simple in structure, waste heat is fully utilized, energy consumption is reduced, hydrogen purity and yield are improved, and carbon dioxide is captured.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen production, and in particular to equipment for preparing hydrogen from biomass, a method for preparing hydrogen from biomass and applications. Background Art

[0002] As a clean energy, hydrogen produces only water during its use, which is environmentally friendly. However, currently, about 76.73% of hydrogen comes from natural gas and coal, of which 22.51% comes from natural gas, 54.22% comes from coal, and 20.82% comes from industrial by-products. The main emission of the conversion process is CO 2 There is no effective capture, which means that the current fossil-based hydrogen energy system will exacerbate the greenhouse effect.

[0003] The chemical composition of biomass is similar to that of fossil energy. Although it contains slightly more oxygen, it has the advantages of wide distribution, low pollution, high reserves, and carbon neutrality. The development and utilization of biomass is one of the important means to achieve the dual carbon goals. The utilization of biomass mainly includes biological conversion methods such as fermentation, as well as thermochemical conversion methods such as pyrolysis, gasification, and combustion. Among them, the thermochemical conversion method of biomass has problems such as the production of tar, high energy consumption, low product calorific value, and low utilization rate, which restricts the further development of biomass resource utilization.

[0004] Chinese patent CN101045524B discloses a method for producing hydrogen-rich gas by catalytic gasification of solid fuels. The solid fuel refers to biomass or coal. The technical solution is that a solid heat carrier circulates between a pyrolysis reactor, a catalytic reforming reactor, and a combustion reactor. The pyrolysis reactor and the catalytic reforming reactor are atmospheric pressure gas-solid countercurrent moving beds or bubbling beds. The inlet of the combustion reactor is connected to a riser, and air is introduced into the riser, which is a atmospheric pressure fast fluidized bed. After the solid fuel is mixed with the solid heat carrier, rapid pyrolysis occurs in the pyrolysis reactor. The pyrolysis volatile products and water enter the catalytic reforming reactor for catalytic steam reforming reaction (i.e., water-gas shift reaction), and CaO absorbs CO 2 The formed CaCO 3 In the combustion reactor, the semi-coke and carbon deposits accumulated on the carrier are fully burned under the action of air, and the temperature is controlled at 850-1000℃. 3 Decomposition and regeneration. However, this treatment method is not conducive to carbon capture, has high energy consumption, and the solid heat carrier only plays the role of heat transfer and catalytic pyrolysis.

[0005] Chinese patent CN104591087A discloses a synergistic process for biomass chemical chain reforming hydrogen production and tar suppression. The oxygen carrier is an iron-based composite oxygen carrier, which circulates between a fuel reactor (850-950°C), a cyclone separator, a steam reforming reactor (850-900°C), and a regeneration reactor (800-850°C). Biomass, water vapor and oxygen carrier react in the fuel reactor, and the generated solids and gases are separated by a cyclone separator. The separated gas is synthesis gas, which is collected after an ice bath. The separated solid is a reduced oxygen carrier, which enters the steam reforming reactor to add water to produce hydrogen, and the oxygen carrier after the reaction is oxidized and regenerated by air in the regeneration reactor. However, the temperature of the reaction system is high, which is not conducive to suppressing tar production. The gas after cyclone separation is ice-bathed. It is speculated that the gas contains a large amount of water vapor, which is condensed by the ice bath. This method wastes a lot of heat.

[0006] Chinese patent CN103672873A discloses a continuously operating solid fuel chemical chain reaction system. However, the biomass gasification reaction and oxygen carrier reduction reaction are separated by a porous partition, resulting in low reaction efficiency and low heat utilization; the oxygen carrier is transported by a spiral between the reactors, which is difficult to withstand the high temperature of the process.

[0007] Chinese patent CN103113917A discloses a solid fuel chemical chain gasification hydrogen production system and method. The solid fuel is a carbon-containing substance, including coal, biomass, petroleum coke or their mixture. The process includes an air reactor, a combustion reactor, a syngas conversion device, a CO 2 Adsorption unit, calciner, CaO tempering unit, etc. Solid fuel and water vapor are burned in the reactor, and the generated gas enters the synthesis gas conversion unit, CO and H 2 O reacts to give H 2 The resulting mixed gas then enters the CO 2 Adsorption unit, H is obtained after CaO adsorption 2 , CaCO 3 Regeneration through calcination furnace and tempering. However, the energy consumption of CaO regeneration in this process is high, and the air reactor, combustion reactor, CO 2 A gas-solid separation device is provided after the outlet of the adsorption unit, and the process is complicated.

[0008] It can be seen that there are two main types of hydrogen production technologies combining biomass and chemical chains: one is to gasify biomass in an independent reactor or space, and then use the gasification gas to reduce the oxygen carrier, and the reduced oxygen carrier reacts with water vapor to produce hydrogen; the other is to gasify biomass and oxygen carrier together, and the generated gas reacts with water vapor to produce hydrogen through a water-gas shift reaction. However, these two types of technologies generally have the problems of complex process, low thermal utilization, low hydrogen production efficiency, and inconvenient carbon capture.

[0009] In view of this, the present invention is proposed. Summary of the invention

[0010] The first purpose of the present invention is to provide a device for preparing hydrogen from biomass, which has a simple structure and uses the oxygen-depleted waste gas generated by an air oxidation reactor to dry the biomass, thereby fully utilizing the waste heat; a crushing unit and a granulating unit are provided to crush and compress the biomass to avoid the introduction of oxygen, give full play to the reducing properties of the biomass to reduce the oxygen carrier, and avoid the introduction of nitrogen, thereby reducing the gas separation cost, reducing part of the heat loss, reducing energy consumption, and improving the purity of hydrogen; the use of a biomass hydrogen production reduction reactor simplifies the reaction process; a hydrogen purification device is provided to purify and separate hydrogen and capture carbon dioxide; the air oxidation reactor can store heat and oxygen for the oxygen carrier, so that the oxygen carrier has heat carrying, oxygen carrying and catalytic functions at the same time; the water vapor in the synthesis gas is separated by a first heat exchanger and introduced into the reaction system for water replenishment, which can promote the water gas reaction, prevent the generation of tar and carbon deposition, and increase the hydrogen yield.

[0011] The second object of the present invention is to provide a method for preparing hydrogen from biomass, which has a simple process, can realize waste heat utilization, reduce energy consumption, and obtain high-purity H 2 While capturing CO 2 , and can also effectively control the generation of tar and carbon deposits, and increase hydrogen production and hydrogen purity.

[0012] The third object of the present invention is to provide an apparatus for preparing hydrogen from biomass or a method for preparing hydrogen from biomass for use in preparing hydrogen.

[0013] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0014] The present invention first provides a device for preparing hydrogen from biomass, comprising a biomass pretreatment system and a chemical chain hydrogen production system; the biomass pretreatment system comprises a drying unit, a crushing unit and a granulation unit connected in sequence; the chemical chain hydrogen production system comprises a biomass hydrogen production reduction reactor, a hydrogen purification device connected to the synthesis gas outlet of the biomass hydrogen production reduction reactor, a dust collector connected to the solid outlet of the biomass hydrogen production reduction reactor, and a regeneration storage tank and an air oxidation reactor connected to the dust collector in sequence; the air oxidation reactor is also connected to the biomass hydrogen production reduction reactor; wherein the granulation unit is connected to the biomass hydrogen production reduction reactor; the hydrogen purification device is used for purifying and separating hydrogen and capturing carbon dioxide; a first heat exchanger is arranged between the synthesis gas outlet of the biomass hydrogen production reduction reactor and the hydrogen purification device, and the water vapor outlet of the first heat exchanger is connected to the biomass hydrogen production reduction reactor; the oxygen-depleted waste gas outlet of the air oxidation reactor is connected to the drying unit.

[0015] Furthermore, a feeding tank is provided between the granulation unit and the biomass hydrogen production reduction reactor.

[0016] Furthermore, a second heat exchanger is provided between the air oxidation reactor and the drying unit.

[0017] Furthermore, the hydrogen purification device includes a PSA purification device.

[0018] Furthermore, an oxygen carrier lifting unit is provided between the biomass hydrogen production reduction reactor and the dust collector, and the oxygen carrier lifting unit comprises a pipeline into which nitrogen is blown.

[0019] Furthermore, the water vapor outlet of the first heat exchanger is respectively connected to the middle, bottom and top of the biomass hydrogen reduction reactor.

[0020] The present invention further provides a method for preparing hydrogen from biomass, which is applicable to the above-mentioned equipment for preparing hydrogen from biomass, comprising the following steps: in a drying unit, the biomass is dried by using the oxygen-poor waste gas generated by the air oxidation reactor, the dried biomass is sequentially introduced into a crushing unit and a granulating unit for crushing and granulating to obtain treated biomass; the treated biomass is introduced into a biomass hydrogen production reduction reactor containing an oxygen carrier to perform a hydrogen production reaction to obtain synthesis gas and solid; wherein the main components of the synthesis gas include hydrogen, carbon dioxide and water vapor, and the synthesis gas is introduced into a The solid enters the dust collector to separate the biomass ash and the oxygen carrier; the oxygen carrier separated by the dust collector enters the storage tank and the air oxidation reactor in turn for storage and regeneration, and then enters the biomass hydrogen reduction reactor for recycling; the oxygen carrier has heat carrying function, oxygen carrying function and catalytic function at the same time; the water vapor generated by the first heat exchanger between the synthesis gas outlet of the biomass hydrogen reduction reactor and the hydrogen purification device enters the biomass hydrogen reduction reactor for water replenishment.

[0021] Furthermore, the temperature of the oxygen-depleted exhaust gas after heat exchange in the second heat exchanger is 50-110°C.

[0022] Furthermore, the material is pulverized to an average particle size of 2 to 5 mm.

[0023] Furthermore, the treated biomass has a diameter of 5 to 8 mm and a length of 10 to 15 mm.

[0024] Further, the processed biomass is stored in a feeding tank.

[0025] Furthermore, the temperature of the hydrogen production reaction is 500-800°C.

[0026] Furthermore, the reaction time of the hydrogen production reaction is 40 to 60 minutes.

[0027] Furthermore, part of the water vapor generated by the first heat exchanger is used to transport the treated biomass into the middle of the biomass hydrogen reduction reactor; another part of the water vapor generated by the first heat exchanger is directly transported to the top and bottom of the biomass hydrogen reduction reactor.

[0028] Furthermore, the solid is lifted to the dust collector by an oxygen carrier lifting unit, and the nitrogen in the oxygen carrier lifting unit is recycled.

[0029] The present invention also provides the use of the above-mentioned device for preparing hydrogen from biomass or the above-mentioned method for preparing hydrogen from biomass in preparing hydrogen.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) The biomass hydrogen production equipment provided by the present invention comprises the following steps: the oxygen-depleted waste gas outputted from the oxygen-depleted waste gas outlet of the air oxidation reactor enters the drying unit to dry the biomass after heat exchange, so that the biomass can enter the pulverizing unit for pulverization and the waste gas is utilized; the pulverized biomass enters the granulating unit for compression and granulation, which can avoid the introduction of oxygen, give full play to the reducing property of the biomass to reduce the oxygen carrier, and avoid the introduction of nitrogen, so that the nitrogen that does not participate in the reaction consumes heat and affects the gas composition, thereby improving the purity of the product hydrogen and reducing the heat consumption of separation; there is no separate biomass gasification reactor and no separate water-gas conversion reactor, and only one biomass hydrogen production reduction reactor is used, which simplifies the reaction process; the water vapor in the synthesis gas generated by the biomass hydrogen production reduction reactor is separated by the first heat exchanger, and the temperature of the reaction system is controlled, and the catalytic effect of the oxygen carrier can prevent the generation of tar and carbon deposition, and the mass transfer and heat transfer in the biomass hydrogen production reduction reactor are strengthened by water, thereby increasing the hydrogen production; the synthesis gas generated by the biomass hydrogen production reduction reactor is separated into H by the hydrogen purification device 2 and capture CO 2 The ash produced after the biomass is fully reacted is lifted along with the oxygen carrier, and then the ash is discharged from the dust collector, which can separate the biomass residue and the oxygen carrier.

[0032] (2) The method for preparing hydrogen from biomass provided by the present invention utilizes the waste heat of the exhaust gas from the air oxidation reactor of the chemical chain system to dry the biomass, and then crush and granulate the biomass. The biomass granules react with an oxygen carrier having oxygen-carrying, heat-carrying and catalytic functions in the hydrogen production reactor in the presence of a large amount of water vapor. The biomass reduces the oxygen carrier and incompletely oxidizes it to obtain CO. 2 and H 2The present invention combines biomass gasification and chemical chain hydrogen production, has a simple process, realizes waste heat utilization, and obtains high-purity H 2 Simultaneous capture of CO 2 , and can also effectively control the generation of tar and carbon deposits.

[0033] (3) The method for preparing hydrogen from biomass provided by the present invention comprises crushing and compressing the biomass into particles before feeding, thereby reducing the amount of O 2 After treatment, the biomass reacts in a high-density state to produce hydrogen, which can fully enable the oxygen carrier to oxidize the biomass, rather than by O 2 Deoxidizes biomass and reduces N in product gas 2 , reduce gas separation costs and reduce some heat losses.

[0034] (4) The method for preparing hydrogen from biomass provided by the present invention adopts an oxygen carrier that has heat-carrying, oxygen-carrying and catalytic functions at the same time, and utilizes an air oxidation reactor to store heat and oxygen for the oxygen carrier. In the biomass hydrogen production reduction reactor, the heat-carrying function provides heat for the reaction, the oxygen-carrying function provides heat for partial oxidation and gasification of biomass, and the catalytic function provides heat for biomass gasification and water-gas reaction to produce hydrogen and tar cracking.

[0035] (5) The method for preparing hydrogen from biomass provided by the present invention introduces a certain amount of water vapor into the reaction system for water replenishment, and uses the water vapor to carry out mass transfer and heat transfer in the reactor. After the biomass reacts to generate hydrogen, the oxidation of hydrogen to generate water is suppressed, thereby preventing the formation of tar. At the same time, the reduced oxygen carrier and water can also generate hydrogen, promote the water-gas reaction, and make the reaction balance of the reduction reactor toward the direction of hydrogen production, thereby increasing the hydrogen yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 This is a schematic diagram of the structure of the equipment for preparing hydrogen from biomass provided by the present invention.

[0038] Reference numerals:

[0039] 1-Biomass pretreatment system; 11-Drying unit; 12-Crushing unit; 13-Pelletizing unit; 14-Feeding tank; 2-Chemical chain hydrogen production system; 21-Biomass hydrogen production reduction reactor; 22-Hydrogen purification device; 23-Dust collector; 24-Regeneration storage tank; 25-Air oxidation reactor; 26-First heat exchanger; 27-Second heat exchanger; 28-Oxygen carrier lifting unit. DETAILED DESCRIPTION

[0040] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0041] If there is no special explanation, in the present invention, "the first aspect", "the second aspect", "the third aspect", "the fourth aspect", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "the first", "the second", "the third", "the fourth", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0042] If there is no special explanation, the "include" and "comprising" mentioned in the present invention represent open-ended or closed-ended expressions. For example, the "include" and "comprising" may represent that other components not listed may also be included or only the listed components may be included or only the listed components may be included.

[0043] If there is no special explanation, in the present invention, "one or more" or "at least one" refers to any one, any two or more of the listed items. Among them, "several" refers to any two or more of the listed items.

[0044] In a first aspect, the present invention provides a device for preparing hydrogen from biomass, such as Figure 1 The figure shows a schematic diagram of the structure of a device for preparing hydrogen from biomass, which includes a biomass pretreatment system 1 and a chemical chain hydrogen production system 2 .

[0045] Among them, see Figure 1 The biomass pretreatment system 1 includes a drying unit 11, a crushing unit 12 and a granulating unit 13 which are connected in sequence and are used to dry, crush and granulate the biomass in sequence.

[0046] See also Figure 1 The chemical chain hydrogen production system 2 includes a biomass hydrogen production reduction reactor 21, a hydrogen purification device 22 connected to the synthesis gas outlet of the biomass hydrogen production reduction reactor 21, a dust collector 23 connected to the solid outlet of the biomass hydrogen production reduction reactor 21, and a regeneration storage tank 24 and an air oxidation reactor 25 connected to the dust collector 23 in sequence.

[0047] See also Figure 1 The air oxidation reactor 25 is also connected to the biomass hydrogen production reduction reactor 21. The air oxidation reactor 25 can store heat and oxygen for the oxygen carrier to regenerate the oxygen carrier.

[0048] The granulation unit 13 is connected to the biomass hydrogen production reduction reactor 21. The granulated biomass enters the biomass hydrogen production reduction reactor 21 for reaction.

[0049] See also Figure 1 A first heat exchanger 26 is provided between the syngas outlet of the biomass hydrogen production reduction reactor 21 and the hydrogen purification device 22, and the water vapor outlet of the first heat exchanger 26 is connected to the biomass hydrogen production reduction reactor 21. The first heat exchanger 26 is used to separate the water vapor in the syngas, and then the separated water vapor enters the biomass hydrogen production reduction reactor 21 for water replenishment, and the syngas whose main components after separation are hydrogen and oxygen enters the hydrogen purification device 22.

[0050] The hydrogen purification device 22 is used to purify and separate hydrogen and capture carbon dioxide.

[0051] See also Figure 1 The oxygen-depleted waste gas outlet of the air oxidation reactor 25 is connected to the drying unit 11. The waste gas generated by the air oxidation reactor 25 enters the drying unit 11, and the waste heat is used to dry the biomass.

[0052] The present invention compresses the volume of biomass, utilizes the oxygen-carrying and catalytic functions of the oxygen carrier, and utilizes the design of the biomass reduction reactor to solve the problem of uniform solid-solid mixing, thereby optimizing the gas composition of biomass gasification and achieving the purpose of simultaneous hydrogen production and carbon capture at a lower temperature.

[0053] Specifically, the present invention utilizes waste gas: the oxygen-depleted waste gas output from the oxygen-depleted waste gas outlet of the air oxidation reactor 25 enters the drying unit 11 to dry the biomass after heat exchange, so that the biomass can enter the pulverizing unit 12 for pulverization.

[0054] The present invention reduces energy consumption: the crushed biomass enters the granulation unit 13 for compression granulation, which can avoid the introduction of oxygen, give full play to the reducing properties of the biomass to reduce the oxygen carrier, and avoid the introduction of nitrogen, which does not participate in the reaction and consumes heat and affects the composition of the gas, thereby improving the purity of the product hydrogen and reducing the separation heat consumption.

[0055] The present invention simplifies the reaction process: there is no separate biomass gasification reactor, no separate water-gas conversion reactor, and only one biomass hydrogen production reduction reactor 21 is used.

[0056] The present invention can avoid tar and carbon deposition: by separating the water vapor in the synthesis gas generated by the biomass hydrogen reduction reactor 21 through the first heat exchanger 26 and controlling the temperature of the reaction system, the catalytic effect of the oxygen carrier can prevent the generation of tar and carbon deposition. In addition, by strengthening the mass transfer and heat transfer in the biomass hydrogen reduction reactor 21 through water, the hydrogen production can be increased.

[0057] The present invention can capture CO 2 The synthesis gas produced by the biomass hydrogen reduction reactor 21 is separated into H by the hydrogen purification device 22. 2 , and capture CO 2 .

[0058] The present invention separates the biomass residue and the oxygen carrier: the ash produced after the biomass is fully reacted is lifted along with the oxygen carrier, and then the ash is discharged from the dust collector 23.

[0059] In some specific implementations, see Figure 1 A feeding tank 14 is provided between the granulation unit 13 and the biomass hydrogen production reduction reactor 21. The granulation unit 13 is connected to the inlet of the feeding tank 14, and the outlet of the feeding tank 14 is connected to the inlet of the biomass hydrogen production reduction reactor 21.

[0060] In some specific implementations, a non-mechanical valve is provided at the bottom of the feeding tank 14 for connecting to the biomass hydrogen reduction reactor 21 .

[0061] In some specific implementations, see Figure 1 A second heat exchanger 27 is provided between the air oxidation reactor 25 and the drying unit 11. The second heat exchanger 27 is used to cool the oxygen-depleted air generated by the air oxidation reactor 25 and then transport it to the drying unit 11.

[0062] In some specific implementations, the air oxidation reactor 25 is provided with an air inlet for introducing air.

[0063] In some specific embodiments, the hydrogen purification device 22 includes a PSA purification device. After purification by the PSA purification device, high-purity H2 , and capture CO 2 .

[0064] In some specific implementations, see Figure 1 An oxygen carrier lifting unit 28 is provided between the biomass hydrogen production reduction reactor 21 and the dust collector 23. The oxygen carrier lifting unit 28 includes a pipeline into which nitrogen is blown. Ash remaining from the biomass reaction moves with the oxygen carrier and can be lifted into the dust collector 23 by the nitrogen in the oxygen carrier lifting unit 28.

[0065] In some specific implementations, see Figure 1 The water vapor outlet of the first heat exchanger 26 is respectively connected to the middle, bottom and top of the biomass hydrogen reduction reactor 21. This is conducive to fully exerting the role of water vapor.

[0066] In a second aspect, the present invention provides a method for preparing hydrogen from biomass, which is applicable to the device for preparing hydrogen from biomass, specifically a method for preparing hydrogen from biomass based on chemical chaining technology, comprising the following steps:

[0067] In the drying unit 11, the biomass is dried using the oxygen-depleted waste gas (oxygen-depleted air) produced by the air oxidation reactor 25, and the dried biomass enters the crushing unit 12 and the granulating unit 13 in sequence for crushing and granulation to obtain the processed biomass (i.e., granular biomass).

[0068] The treated biomass enters the biomass hydrogen production reduction reactor 21 containing an oxygen carrier to produce hydrogen to obtain synthesis gas and solid. The oxygen carrier has heat carrying, oxygen carrying and catalytic functions. The main components of the synthesis gas obtained after the reaction include hydrogen, carbon dioxide and water vapor.

[0069] The synthesis gas enters the hydrogen purification device 22 to purify and separate hydrogen and capture carbon dioxide. The solid enters the dust collector 23 to separate biomass ash (including worn oxygen carriers) and the oxygen carriers. The oxygen carriers separated by the dust collector 23 enter the storage tank and air oxidation reactor 25 in turn for storage and regeneration, and then enter the biomass hydrogen reduction reactor 21 for recycling.

[0070] The oxygen carrier has heat-carrying function, oxygen-carrying function and catalytic function at the same time. Because the reaction of the oxygen carrier in the air oxidation reactor 25 is an exothermic reaction, a large amount of heat is not released to the outside, but stored in the oxygen carrier. The oxygen carrier flows directly from the air oxidation reactor 25 to the biomass hydrogen reduction reactor 21, so the oxygen carrier also has a heat-carrying function.

[0071] The water vapor generated by the first heat exchanger 26 between the synthesis gas outlet of the biomass hydrogen reduction reactor 21 and the hydrogen purification device 22 enters the biomass hydrogen reduction reactor 21 for water replenishment.

[0072] The present invention utilizes the waste heat of the exhaust gas of the chemical chain system air oxidation reactor 25 to dry the biomass, and then crush and granulate it. The biomass particles react with the oxygen carrier having oxygen-carrying, heat-carrying and catalytic functions in the presence of a large amount of water vapor in the hydrogen production reactor; the biomass reduces the oxygen carrier and incompletely oxidizes it to obtain CO. 2 and H 2 The present invention combines biomass gasification and chemical chain hydrogen production, has a simple process, realizes waste heat utilization, and obtains high-purity H 2 Simultaneous capture of CO 2 , and can also effectively control the generation of tar and carbon deposits.

[0073] Specifically, the method for preparing hydrogen from biomass provided by the present invention utilizes the oxygen-poor waste gas generated by the air oxidation reactor 25 to dry the biomass, which can make full use of the waste heat. The waste gas contains very little water, and the temperature is suitable for drying the biomass to facilitate further crushing without causing premature pyrolysis of the biomass. The crushed biomass can make the oxygen carrier and the biomass mix more evenly.

[0074] In addition, the present invention crushes and compresses the biomass into particles before feeding, which reduces the 2 After treatment, the biomass reacts in a high-density state to produce hydrogen, which can fully enable the oxygen carrier to oxidize the biomass, rather than by O 2 Deoxidizes biomass and reduces N in product gas 2 , reduce gas separation costs and reduce some heat losses.

[0075] The present invention adopts a biomass hydrogen production reduction reactor 21, and the biomass and the oxygen carrier directly contact each other to produce hydrogen through solid-solid reaction, and the process is simple.

[0076] The present invention adopts an oxygen carrier having heat-carrying, oxygen-carrying and catalytic functions, and utilizes the air oxidation reactor 25 to store heat and oxygen for the oxygen carrier. In the biomass hydrogen production reduction reactor 21, the heat-carrying function provides heat for reaction, the oxygen-carrying function provides heat for partial oxidation and gasification of biomass, and the catalytic function provides heat for biomass gasification and water-gas reaction hydrogen production and tar cracking.

[0077] The present invention introduces a certain amount of water vapor into the reaction system for water replenishment, and uses the water vapor to carry out mass transfer and heat transfer in the reactor. After the biomass reacts to generate hydrogen, the oxidation of hydrogen to generate water is suppressed, and the generation of tar is prevented. At the same time, the reduced oxygen carrier and water can also generate hydrogen, promote the water-gas reaction, and make the reaction balance of the reduction reactor toward the direction of hydrogen production, thereby increasing the hydrogen yield.

[0078] In addition, the synthesis gas produced by the biomass hydrogen reduction reactor 21 of the present invention is separated into H 2 , and capture CO 2 The ash produced after the biomass is fully reacted is lifted along with the oxygen carrier and discharged from the dust collector 23, so that the biomass residue and the oxygen carrier can be separated.

[0079] In some specific embodiments, the temperature of the oxygen-depleted exhaust gas after heat exchange in the second heat exchanger 27 is 50-110° C., including but not limited to any point value of 50° C., 60° C., 70° C., 80° C., 90° C., 100° C., 110° C., or any range value between two of them. This temperature is suitable for drying biomass to facilitate subsequent pulverization without causing premature pyrolysis of biomass.

[0080] In some specific embodiments, the biomass is preliminarily crushed before drying, and then enters the crushing unit 12 for further crushing after drying.

[0081] In some specific embodiments, the average particle size of the material crushed is 2 to 5 mm. The particle size is moderate, which is convenient for granulation and controls the crushing cost. In addition, particles of this particle size have a large specific surface area and excellent hygroscopicity, which helps to maintain the reactivity of the particles in a humid environment. Particles with this particle size are interlocked with each other, the friction force is moderate, the biomass after compression treatment has moderate anti-fall performance, and it is easy to disperse quickly under the action of temperature and humidity, avoiding particle agglomeration, and ensuring the smooth progress of the reaction. In addition, the particle size after dispersion is about 1 to 2 times that of the oxygen carrier, which can effectively increase the contact area between the particles and the oxygen carrier, improve the reaction efficiency, and thus ensure the reaction effect of the biomass hydrogen production process.

[0082] In some specific embodiments, the diameter of the processed biomass is 5 to 8 mm, such as 6 mm or 7 mm.

[0083] In some specific embodiments, the length of the processed biomass is 10-15 mm, such as 11 mm, 12 mm, 13 mm or 14 mm.

[0084] The processed biomass is controlled within the above-mentioned size, which is beneficial for the rapid and uniform dispersion of the biological particles after entering the biomass hydrogen production reduction reactor 21, avoiding particle agglomeration and ensuring the smooth progress of the reaction.

[0085] In some specific embodiments, after crushing and granulation, the volume of the biomass is compressed to 1 / 12 to 1 / 8 of the original volume.

[0086] In some specific embodiments, the processed biomass is stored in a feed tank 14 .

[0087] In some specific embodiments, the temperature of the hydrogen production reaction is 500-800°C, including but not limited to any point value of 500°C, 600°C, 700°C, 800°C or any range value between two of them. The temperature of the hydrogen production reaction of the present invention is relatively low, which can reduce the generation of tar carbon deposition during the reaction process.

[0088] In some specific embodiments, the reaction time of the hydrogen production reaction is 40 to 60 min, including but not limited to any one of 40 min, 45 min, 50 min, 55 min, and 60 min or a range between any two of them.

[0089] In some specific embodiments, part of the water vapor generated by the first heat exchanger 26 is used to deliver the treated biomass into the middle of the biomass hydrogen reduction reactor 21; another part of the water vapor generated by the first heat exchanger 26 is directly transported to the top and bottom of the biomass hydrogen reduction reactor 21 to give full play to the role of water vapor.

[0090] In some specific embodiments, the solid is lifted to the dust collector 23 by an oxygen carrier lifting unit 28, and the nitrogen in the oxygen carrier lifting unit 28 is recycled.

[0091] In some specific embodiments, the oxygen carrier comprises a composite oxygen carrier of metal oxides containing at least three elements of Fe, Ni, Co, Mo, Mg, K, Cu, and Ca. The oxygen carrier has heat carrying function, oxygen carrying function, and catalytic function.

[0092] It is understandable that the above-mentioned types of oxygen carriers themselves have oxygen carrying functions and catalytic functions, and different metal elements have different oxidation forms, different reaction rates and different catalytic effects. The types of oxygen carriers can be set as needed.

[0093] The reaction of the oxygen carrier in the air oxidation reactor 25 is an exothermic reaction, and a large amount of heat is not released to the outside, but stored in the oxygen carrier. The oxygen carrier flows directly from the air oxidation reactor 25 to the biomass hydrogen reduction reactor 21, so the oxygen carrier also has a heat carrying function.

[0094] In some specific embodiments, the reaction principle and working principle of using the equipment for preparing hydrogen from biomass to prepare hydrogen from biomass are as follows: the oxygen-depleted air after the reaction in the air oxidation reactor 25 is cooled to 50-110°C after heat exchange, and the gas is used to dry the preliminarily crushed biomass; the biomass after drying is further crushed, and the crushed biomass is made into particles with a diameter of about 5mm and a length of about 15mm. The volume of the biomass after treatment is compressed to about 1 / 10 of the original volume and stored in the feeding tank 14 for standby; a non-mechanical valve is provided at the bottom of the feeding tank 14 to connect the biomass hydrogen reduction reactor 21.

[0095] The biomass particles in the feed tank 14 are fed into the middle of the biomass hydrogen production reduction reactor 21 by water vapor above 100°C through a non-mechanical valve, and the biomass particles begin to gasify. The gasified gas in the middle of the reactor is mixed with water vapor and the gasified gas in the lower part of the reactor, reacts with the oxygen carrier, passes through the upper oxygen carrier bed, and reaches the synthesis gas outlet at the upper part of the reduction reactor; the oxygen carrier falls with the biomass, is reduced, mixed, and is accumulated and directly contacted with the biomass in the lower part of the reactor. The biomass continues to be gasified under the catalytic action of the reduced oxygen carrier and in a water-rich environment. As the oxygen carrier slowly moves downward, the biomass is gradually gasified.

[0096] The ash remaining from the biomass reaction moves with the oxygen carrier and is lifted to the dust collector 23 by the nitrogen of the oxygen carrier lifting unit 28. The dust collector 23 separates the biomass ash and the oxygen carrier, and the nitrogen is recycled as lifting gas. The oxygen carrier returns to the regeneration tank 24 and then enters the air oxidation reactor 25 for regeneration.

[0097] The main components of the gas produced in the upper part of the biomass hydrogen reduction reactor 21 include H 2 , CO 2 , H 2 O (water vapor), the gas is heat exchanged in the first heat exchanger 26 to separate the water vapor, and then purified by PSA to obtain high-purity H 2 and CO 2 .

[0098] In a third aspect, the present invention provides the use of the device for preparing hydrogen from biomass or the method for preparing hydrogen from biomass in preparing hydrogen.

[0099] The equipment and method for preparing hydrogen from biomass provided by the present invention simplify the process and equipment, reduce energy consumption, effectively control the generation of tar and carbon deposits, increase hydrogen production and hydrogen purity, and obtain high-purity H 2 While capturing CO 2 , with broad application prospects.

[0100] The embodiments of the present invention will be described in detail below in conjunction with the examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. If no specific conditions are specified in the examples, the conditions are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be obtained commercially.

[0101] Example 1

[0102] The biomass hydrogen production equipment provided in this embodiment includes a biomass pretreatment system 1 and a chemical chain hydrogen production system 2. Figure 1 . Among them, the biomass pretreatment system 1 includes a drying unit 11, a crushing unit 12 and a granulation unit 13 connected in sequence. The chemical chain hydrogen production system 2 includes a biomass hydrogen production reduction reactor 21, a PSA purification device connected to the synthesis gas outlet of the biomass hydrogen production reduction reactor 21, a dust collector 23 connected to the solid outlet of the biomass hydrogen production reduction reactor 21, and a regeneration storage tank 24 and an air oxidation reactor 25 connected to the dust collector 23 in sequence; the air oxidation reactor 25 is also connected to the biomass hydrogen production reduction reactor 21. The PSA purification device is used to purify and separate hydrogen and capture carbon dioxide; the granulation unit 13 is connected to the biomass hydrogen production reduction reactor 21; a first heat exchanger 26 is arranged between the synthesis gas outlet of the biomass hydrogen production reduction reactor 21 and the PSA purification device, and the water vapor outlet of the first heat exchanger 26 is connected to the biomass hydrogen production reduction reactor 21, and is respectively connected to the middle, bottom and top of the biomass hydrogen production reduction reactor 21; the oxygen-depleted waste gas outlet of the air oxidation reactor 25 is connected to the drying unit 11. A feeding tank 14 is provided between the granulation unit 13 and the biomass hydrogen reduction reactor 21. A second heat exchanger 27 is provided between the air oxidation reactor 25 and the drying unit 11. An oxygen carrier lifting unit 28 is provided between the biomass hydrogen reduction reactor 21 and the dust collector 23, and the oxygen carrier lifting unit 28 includes a pipeline into which nitrogen is blown.

[0103] Example 2

[0104] The device for preparing hydrogen from biomass of Example 1 is used. The method for preparing hydrogen from biomass provided in this embodiment includes the following steps: the oxygen-depleted exhaust gas generated by the air oxidation reactor 25 enters the second heat exchanger 27 for heat exchange to reduce the temperature of the oxygen-depleted exhaust gas to 110°C, and then enters the drying unit 11 to dry the biomass. The dried biomass enters the crushing unit 12 and the granulating unit 13 in turn for crushing (crushing to an average particle size Dv50 of 3 mm) and granulation to obtain processed biomass with a diameter of 5 to 8 mm and a length of 10 to 15 mm (there are errors in the diameter and length, so they are range values), which are stored in the feeding tank 14.

[0105] The treated biomass in the feeding tank 14 is fed into the middle of the biomass hydrogen production reduction reactor 21 containing an oxygen carrier by water vapor through a non-mechanical valve for hydrogen production reaction, wherein the oxygen carrier is a composite oxygen carrier containing ferric oxide, nickel oxide and calcium oxide, and the oxygen carrier has oxygen carrying, heat carrying and catalytic functions. The temperature of the hydrogen production reaction is 500°C and the reaction time is 40 minutes. During the reaction, the biomass reacts with the oxygen carrier (the biomass reduces the oxygen carrier) and generates CO at the same time. 2 , H 2 and water, and after gas-solid separation, synthesis gas and solid are obtained respectively. The main components of the synthesis gas include hydrogen, carbon dioxide and water vapor.

[0106] Subsequently, the synthesis gas enters the hydrogen purification device 22 to purify and separate the hydrogen to obtain high-purity H 2 , while capturing carbon dioxide.

[0107] The solid enters the dust collector 23 under the action of nitrogen in the oxygen carrier lifting unit 28 to separate the biomass ash and oxygen carriers; the oxygen carriers separated by the dust collector 23 enter the storage tank and the air oxidation reactor 25 in turn for storage and regeneration, and the nitrogen is recycled as lifting gas and then enters the biomass hydrogen reduction reactor 21 for recycling.

[0108] The water vapor generated by the first heat exchanger 26 between the synthesis gas outlet of the biomass hydrogen reduction reactor 21 and the hydrogen purification device 22 is partially sent to the middle part of the biomass hydrogen reduction reactor 21, and the remaining water vapor is transported to the top and bottom of the biomass hydrogen reduction reactor 21.

[0109] Example 3

[0110] The method for preparing hydrogen from biomass provided in this embodiment is basically the same as that in Embodiment 2, except that the oxygen-depleted waste gas produced by the air oxidation reactor 25 enters the second heat exchanger 27 for heat exchange, so that the temperature of the oxygen-depleted waste gas is reduced to 60°C.

[0111] Example 4

[0112] The method for preparing hydrogen from biomass provided in this embodiment is basically the same as that in Embodiment 2, except that the temperature of the hydrogen production reaction is 600° C. and the reaction time is 60 min.

[0113] Example 5

[0114] The method for preparing hydrogen from biomass provided in this embodiment is basically the same as that in Embodiment 2, except that the temperature of the hydrogen production reaction is 800° C. and the reaction time is 40 min.

[0115] The purity and hydrogen production of the hydrogen produced in Examples 2 to 5, as well as the carbon conversion rate results are shown in Table 1. It can be seen that the hydrogen produced by the device and method for preparing hydrogen from biomass provided by the present invention has high purity and can increase the hydrogen production.

[0116] Table 1 Hydrogen purity, hydrogen production, and carbon conversion results

[0117]

[0118] Furthermore, 10 cycles of stability tests were carried out using Example 4, and the hydrogen purity and carbon conversion rate did not change significantly; the oxygen carrier after dust removal after 10 cycles was tested, and no obvious carbon deposition was found; the syngas outlet sample of the biomass hydrogen reduction reactor 21 in the 10th cycle was measured, and the tar content was less than 5 mg / m 3 It can be seen that the device and method for preparing hydrogen from biomass provided by the present invention can prevent the generation of tar and carbon deposits.

[0119] Although the present invention has been illustrated and described with specific embodiments, it should be appreciated that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Those skilled in the art should understand that the technical solutions described in the above embodiments may be modified, or some or all of the technical features thereof may be replaced by equivalents without departing from the spirit and scope of the present invention. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention. Therefore, this means that all such replacements and modifications within the scope of the present invention are included in the appended claims.

Claims

1. A device for preparing hydrogen from biomass, characterized in that: Including biomass pretreatment system and chemical chain hydrogen production system; The biomass pretreatment system comprises a drying unit, a crushing unit and a granulating unit connected in sequence; The chemical chain hydrogen production system comprises a biomass hydrogen production reduction reactor, a hydrogen purification device connected to the synthesis gas outlet of the biomass hydrogen production reduction reactor, a dust collector connected to the solid outlet of the biomass hydrogen production reduction reactor, and a regeneration storage tank and an air oxidation reactor connected to the dust collector in sequence; the air oxidation reactor is also connected to the biomass hydrogen production reduction reactor; Wherein, the granulation unit is connected to the biomass hydrogen production reduction reactor; The hydrogen purification device is used to purify and separate hydrogen and capture carbon dioxide; A first heat exchanger is provided between the synthesis gas outlet of the biomass hydrogen production reduction reactor and the hydrogen purification device, and the water vapor outlet of the first heat exchanger is connected to the biomass hydrogen production reduction reactor; The oxygen-depleted exhaust gas outlet of the air oxidation reactor is connected to the drying unit.

2. The device for preparing hydrogen from biomass according to claim 1, characterized in that: At least one of the following conditions is met: (1) A feeding tank is provided between the granulation unit and the biomass hydrogen production reduction reactor; (2) A second heat exchanger is provided between the air oxidation reactor and the drying unit.

3. The device for preparing hydrogen from biomass according to claim 1, characterized in that: The hydrogen purification device comprises a PSA purification device.

4. The device for preparing hydrogen from biomass according to claim 1, characterized in that: An oxygen carrier lifting unit is arranged between the biomass hydrogen production reduction reactor and the dust collector, and the oxygen carrier lifting unit comprises a pipeline into which nitrogen is blown.

5. The device for preparing hydrogen from biomass according to claim 1, characterized in that: The water vapor outlet of the first heat exchanger is connected to the middle, bottom and top of the biomass hydrogen reduction reactor respectively.

6. A method for preparing hydrogen from biomass, applicable to the device for preparing hydrogen from biomass as claimed in any one of claims 1 to 5, characterized in that: The steps include: In the drying unit, the oxygen-depleted waste gas generated by the air oxidation reactor is used to dry the biomass, and the dried biomass enters the crushing unit and the granulating unit in sequence for crushing and granulation to obtain the processed biomass; The treated biomass enters a biomass hydrogen production reduction reactor containing an oxygen carrier to undergo a hydrogen production reaction to obtain synthesis gas and solids; wherein the main components of the synthesis gas include hydrogen, carbon dioxide and water vapor, and the synthesis gas enters a hydrogen purification device to purify and separate hydrogen and capture carbon dioxide at the same time; the solid enters a dust collector to separate biomass ash and the oxygen carrier; The oxygen carrier separated by the dust collector enters the storage tank and the air oxidation reactor in turn for storage and regeneration, and then enters the biomass hydrogen reduction reactor for recycling; the oxygen carrier has heat carrying function, oxygen carrying function and catalytic function at the same time; The water vapor generated by the first heat exchanger between the synthesis gas outlet of the biomass hydrogen production reduction reactor and the hydrogen purification device enters the biomass hydrogen production reduction reactor for water replenishment.

7. The method for preparing hydrogen from biomass according to claim 6, characterized in that: At least one of the following conditions is met: (1) The temperature of the oxygen-depleted exhaust gas after heat exchange in the second heat exchanger is 50-110° C.; (2) the material is pulverized to an average particle size of 2 to 5 mm; (3) The diameter of the treated biomass is 5 to 8 mm and the length is 10 to 15 mm; (4) The treated biomass is stored in a feeding tank.

8. The method for preparing hydrogen from biomass according to claim 6, characterized in that: At least one of the following conditions is met: (1) The temperature of the hydrogen production reaction is 500-800°C; (2) The reaction time of the hydrogen production reaction is 40 to 60 minutes.

9. The method for preparing hydrogen from biomass according to claim 6, characterized in that: At least one of the following conditions is met: (1) A portion of the water vapor generated by the first heat exchanger is used to transport the treated biomass into the middle of the biomass hydrogen reduction reactor; another portion of the water vapor generated by the first heat exchanger is directly transported to the top and bottom of the biomass hydrogen reduction reactor; (2) The solid is lifted to the dust collector by an oxygen carrier lifting unit, and the nitrogen in the oxygen carrier lifting unit is recycled.

10. Use of the device for preparing hydrogen from biomass according to any one of claims 1 to 5 or the method for preparing hydrogen from biomass according to any one of claims 6 to 9 in preparing hydrogen.

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