Method for regulating and controlling components of wood vinegar

Abstract

The invention discloses a wood vinegar component regulation and control method, and belongs to the technical field of biomass pyrolysis. The preparation method comprises the following steps: (1) preparing modified red mud loaded with a nano material; (2) pretreating the biomass; and (3) catalyzing the biomass pretreated in the step (2) to be pyrolyzed in an inert gas protection environment by using the modified red mud prepared in the step (1) as a catalyst. According to the method, in the biomass pyrolysis process, the modified red mud is added to serve as a catalyst to catalyze biomass pyrolysis, components of the wood vinegar obtained through biomass pyrolysis are effectively regulated and controlled, the yield of target components in the wood vinegar is increased, and therefore the wood vinegar with the high additional value is obtained; the catalytic stability of the catalyst is improved, and the biomass pyrolysis efficiency is promoted.

Description

Technical Field

[0001] The invention belongs to the technical field of biomass pyrolysis and relates to a method for regulating components of wood vinegar. Background Art

[0002] Red mud is the industrial waste discharged after chemical treatment of bauxite during the production of alumina. Every ton of alumina produced will produce about 1-2 tons of red mud. With the rapid development of today's industry, the scale of the alumina industry continues to expand, and the amount of red mud discharged is huge. The high discharge of red mud has led to a sharp increase in the amount of red mud accumulation, which not only occupies a large amount of precious land resources, but also poses a serious threat to the ecological environment. Red mud contains a variety of heavy metals and alkaline-soluble substances. These substances will penetrate into the soil and water bodies with natural factors such as rain erosion, causing soil salinization and water pollution, thereby destroying the ecological balance and endangering human health.

[0003] At present, the main treatment methods for red mud include landfill, stockpiling and some limited attempts at resource utilization. However, landfill and stockpiling are just simple storage of red mud, which cannot fundamentally eliminate its potential threat to the environment, and it also requires a large amount of manpower, material and financial resources to be continuously invested in site maintenance and environmental monitoring. In terms of resource utilization, although some studies have attempted to use red mud in the preparation of building materials, adsorbents and other fields, these applications generally have problems such as low product added value and unstable performance, making it difficult to achieve large-scale and effective utilization of red mud.

[0004] As an important by-product of biomass pyrolysis, wood vinegar has a wide source and low cost. It is mainly composed of various organic components such as organic acids, phenols, alcohols, furans, ketones, etc. Furans are useful in the fields of agricultural growth promotion, as chemical raw material solvents, pharmaceutical antibacterial and antioxidant, and food preservation and deodorization; phenolic substances (such as guaiacol, p-cresol, etc.) have antioxidant properties and have potential applications in chemical synthesis and pharmaceutical intermediates; ketones can regulate plant growth, as chemical solvents and raw materials, have medicinal value, and can also be used in food seasoning and environmental protection.

[0005] However, in the current process of preparing wood vinegar by pyrolysis of biomass, due to the complex components of wood vinegar and the complex mutual conversion relationship between the components, slight changes in temperature, time and heating rate during the pyrolysis process will cause dynamic changes in the proportions of the components. Therefore, the components of wood vinegar prepared by pyrolysis of biomass are difficult to regulate, which easily leads to a low yield of the required components in the prepared wood vinegar and unstable quality of the wood vinegar product, which greatly limits the further development and utilization of wood vinegar.

[0006] Therefore, it is necessary to provide a method for regulating the components of wood vinegar, which can effectively regulate the components of wood vinegar obtained by pyrolysis of biomass, thereby increasing the yield of target components, improving the quality stability of wood vinegar products, and facilitating the further development and utilization of wood vinegar. Summary of the invention

[0007] In order to overcome the problems in the background technology, the present invention uses modified red mud loaded with nanomaterials as a catalyst. On the one hand, the biomass pyrolysis process is catalyzed, so that the yield of the target component in the wood vinegar obtained by the pyrolysis of the biomass is improved, which helps to maintain the stability of the wood vinegar product and is conducive to the further development and utilization of the wood vinegar. On the other hand, the special structure and properties of the nanomaterials are utilized to reduce the activation energy of the pyrolysis reaction and promote the cracking of biomass molecules, thereby optimizing the pyrolysis process, allowing the pyrolysis reaction to be carried out efficiently at a relatively low temperature, and improving the yield of the target component of the wood vinegar, thereby improving the quality of the wood vinegar product.

[0008] In order to achieve the above object, the present invention is implemented by the following technical solutions:

[0009] The method comprises the following steps:

[0010] (1) preparing modified red mud loaded with nanomaterials;

[0011] (2) pre-treating biomass;

[0012] (3) Using the modified red mud prepared in step (1) as a catalyst, catalyzing the pyrolysis of the biomass pretreated in step (2) under an inert gas protection environment. The inert gas atmosphere can create an oxygen-free pyrolysis environment, prevent excessive oxidation of the biomass during the pyrolysis process, ensure the stability of the pyrolysis product, and improve the yield of the target product.

[0013] Preferably, in step (1), the specific steps of preparing the modified red mud loaded with nanomaterials include:

[0014] S1: pre-treating red mud and nanomaterials respectively;

[0015] S2: loading the nanomaterial pretreated in step S1 on the surface of the pretreated red mud to complete loading modification;

[0016] S3: The red mud subjected to loading modification in step S2 is sequentially dried, molded, granulated, calcined, and activated to obtain modified red mud.

[0017] Preferably, in step S1, the specific process of pretreating the red mud is: drying the red mud at 30-200°C for 0.5-10h to remove free water therein, then ball-milling the dried red mud into red mud powder, with a ball-to-material ratio of 1:1-2:1, and finally heating the red mud powder to 300-800°C at a heating rate of 1-50°C / min, and air calcining the red mud powder for 0.5-10h to remove volatiles, pollutants and water-soluble substances contained in the red mud, thereby completing the pretreatment of the red mud.

[0018] Preferably, in step S1, the specific process of pre-treating the nano material is as follows: the nano material includes nano metal oxide or carbon nano tube, the nano metal oxide is calcined at 200-400°C for 1-3h to remove the moisture and impurities adsorbed on its surface and improve its surface activity, and then the nano metal oxide is washed to neutrality and dried to complete the pre-treatment of the nano metal oxide; a mixed liquid with a volume ratio of concentrated nitric acid: concentrated sulfuric acid = 1:3 is used as a reflux liquid, and the carbon nano tube is refluxed at 60-80°C for 2-6h to increase its surface functional groups and enhance its binding ability with red mud, and then the carbon nano tube is washed to neutrality and dried to complete the pre-treatment of the carbon nano tube. The nano metal oxide includes nano titanium dioxide, nano silicon dioxide, zinc oxide, etc., and the average particle size of the nano material is controlled between 10-100nm.

[0019] Preferably, in step S2, the specific process of loading modification is: adding the pretreated nanomaterial to water, ultrasonically dispersing for 0.5-2h, obtaining a suspension with a concentration of 0.5-5g / L, adding red mud to the suspension according to the mass ratio of red mud: nanomaterial = 10-50:1, and stirring for 2-6h at room temperature, so that the nanomaterial is fully adsorbed on the surface of the red mud, and then heating and stirring in a water bath at 60-80°C for 4-8h to further promote the combination of the nanomaterial and the red mud, and then placing the red mud loaded with the nanomaterial in a muffle furnace, heating the red mud loaded with the nanomaterial to 300-600°C at a heating rate of 2-8°C / min, and roasting for 2-5h to complete the loading modification. During the high-temperature roasting process, chemical bonding and structural reconstruction occur between the nanomaterial and the red mud, forming a stable active center, and further improving the catalytic performance and stability of the catalyst.

[0020] Preferably, in step S3, the loaded modified red mud is pressed and formed by a tablet press or an extruder, and then the block is crushed and then subjected to a rolling granulation process to form modified red mud particles, and finally the modified red mud particles are calcined at 300-600° C. for 2-6 hours to enhance its mechanical strength and stability, and activated at 400-800° C. for 1-5 hours. During the activation process, the active sites on the catalyst surface are further optimized, and the catalytic performance of the catalyst is further improved.

[0021] In the step (2), the specific process of biomass pretreatment includes: crushing and screening the biomass to obtain biomass particles with a particle size of 1-6mm, and then removing impurities, drying naturally or drying with hot air in sequence. Collect various types of biomass raw materials from farmland, forest areas and other places, crush the collected biomass raw materials using equipment such as pulverizers and crushers, and screen them after crushing. Classify the raw materials according to particle size to make the particle size uniform, ensure the consistency of heat transfer and reaction during pyrolysis, and remove oversized or undersized particles to avoid affecting the pyrolysis effect. Use magnetic separation, air separation, gravity separation and other methods to remove non-biomass impurities such as metal impurities, stones, plastics, etc. in the raw materials. Spread the biomass raw materials in a well-ventilated and sunny place for drying to allow the water to evaporate naturally, or use drying furnaces, dryers and other equipment to heat and dry the raw materials through heat sources such as hot air and steam.

[0022] Preferably, in step (3), the pyrolysis temperature is controlled to be 350-500° C., the mass of the modified red mud added is controlled to be less than 5% of the total mass of the modified red mud and the biomass, and the furanic substances in the wood vinegar are regulated to increase;

[0023] The pyrolysis temperature is controlled to be 500-600°C, the mass of the modified red mud added is controlled to be 5%-20% of the total mass of the modified red mud and the biomass, and the ketone substances in the wood vinegar are regulated to increase;

[0024] The pyrolysis temperature is controlled at 400-600℃, and the mass of modified red mud added is controlled to be 25%-35% of the total mass of modified red mud and biomass, so as to adjust the increase of phenolic substances in wood vinegar. Through precise temperature control and the catalytic effect of modified red mud catalyst, the proportion of various organic components in wood vinegar can be regulated. By accurately controlling the ratio of biomass raw materials and catalysts, it can not only ensure that the catalyst plays an effective catalytic role in the pyrolysis of biomass and promote the efficient pyrolysis reaction, but also reasonably control costs, avoid the problem of greatly reduced pyrolysis effect due to improper use of catalysts, and ensure the economy and stability of the entire production process. At the beginning of pyrolysis, the heating rate can be controlled between 1-50℃ / min, so that the biomass reaches the reaction temperature faster, reducing secondary reactions during the pyrolysis process, and avoiding excessive heating rates that lead to excessively high local temperatures and affect product distribution.

[0025] Preferably, the pyrolysis time is 10-180 min. A shorter residence time is favorable for the production of low molecular weight products, such as organic acids and aldehydes, while a longer residence time is favorable for the production of high molecular weight products, such as phenol and coke.

[0026] Preferably, the inert gas includes nitrogen, argon, helium, ammonia, and carbon dioxide, and the flow rate of the inert gas is 50-100 mL / min.

[0027] Beneficial effects of the present invention:

[0028] 1. The present invention uses modified red mud loaded with nanomaterials as a catalyst to catalyze the pyrolysis reaction of biomass, effectively regulates the pyrolysis reaction path, utilizes the characteristics of modified red mud having a certain selectivity for the generation of different components in wood vinegar under different pyrolysis temperature conditions, and combines the control of the pyrolysis temperature to achieve effective regulation of the yield of the target component in the wood vinegar, so that the yield of the target component in the wood vinegar obtained after the pyrolysis of the biomass is significantly improved, thereby improving the quality and utilization value of the wood vinegar.

[0029] 2. Red mud is abundant and inexpensive. By using modified red mud as a catalyst, red mud can be utilized as a resource and waste can be turned into treasure, which is conducive to alleviating the potential threat to the environment caused by red mud landfill and stacking, and is also conducive to reducing the comprehensive cost of regulating the components of wood vinegar.

[0030] 3. The present invention can achieve the regulation of wood vinegar components and improve the yield of target components. Therefore, the present invention can effectively reduce the problems of environmental pollution caused by the difficulty in regulating wood vinegar components and the generation of a large number of non-target components by achieving the regulation of wood vinegar components, and has good environmental benefits.

[0031] 4. The present invention modifies red mud by loading nanomaterials on the surface of red mud, and increases the contact area between biomass and catalyst by using the extremely high specific surface area and abundant active sites of nanomaterials, thereby achieving the effect of improving pyrolysis efficiency. At the same time, by using the high specific surface area, abundant surface active sites, quantum size effect, surface defects and lattice distortion, excellent electron transport performance, thermal stability and chemical stability, photocatalytic performance and the ability to inhibit sintering and agglomeration of nanomaterials, the activation energy of pyrolysis reaction is effectively reduced, the cracking of biomass molecules is promoted, and the pyrolysis process of biomass can be carried out efficiently at a relatively low temperature. In addition, the nanomaterials are evenly dispersed on the surface of red mud to form a stable active structure, maintain the number and activity of active sites of the catalyst, enhance the structural stability of the catalyst, and inhibit the sintering and agglomeration of the catalyst during the pyrolysis process.

[0032] 5. The present invention can also make full use of the characteristics of different nanomaterials to produce positive effects on the biomass pyrolysis process by loading different nanomaterials on red mud. For example, when nano-silicon dioxide is loaded, the deposition of carbon deposits on the catalyst surface during the pyrolysis process can be effectively reduced, thereby extending the service life of the catalyst, reducing the frequency of catalyst replacement, and ensuring the continuity and stability of the pyrolysis production process; when nano-titanium dioxide is loaded, the catalytic activity, selective catalysis, inhibition of side reactions, enhanced thermal stability and structural stability can be improved, and photocatalytic performance and synergistic effects can be utilized to significantly improve the catalytic performance of red mud in biomass pyrolysis, while having the advantages of environmental friendliness and cost reduction; red mud modified by loading carbon nanotubes can improve electrical conductivity, thermal conductivity and mechanical strength, increase specific surface area and active sites, promote biomass cracking, inhibit carbon deposition, and enhance catalyst stability and service life. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below in conjunction with specific embodiments, but the protection scope of the present invention is not limited to the described contents.

[0034] In the embodiments and comparative examples of the present invention, chemical reagents not specifically described were uniformly commercially available analytically pure reagents for the experiments.

[0035] Example 1

[0036] This embodiment performs biomass pyrolysis according to the following steps:

[0037] (1) Red mud pretreatment: The red mud was dried at 60°C for 8 hours to fully evaporate the free water therein. The dried red mud was placed in a ball mill with a ball-to-material ratio of 1:1 and ball-milled at a speed of 500 r / min for 3 hours to obtain pulverized red mud powder. Finally, the red mud powder was calcined at 500°C for 8 hours to complete the pretreatment of the red mud.

[0038] (2) Nanomaterial pretreatment: Select nano titanium dioxide (TiO 2 ), calcined it in a muffle furnace at 300°C for 2h, and then washed the nano-TiO2 with deionized water to neutrality and dried to complete the pretreatment of the nano-material.

[0039] (3) Load modification: The pretreated nano-TiO 2 Dispersed in deionized water, ultrasonically dispersed for 1 hour to form a suspension with a concentration of 2g / L. The pretreated red mud powder was added to the suspension. 2 The mass ratio was 20:1, stirred at room temperature for 4 h, and then heated and stirred in a 70°C water bath for 6 h. 2 The red mud was placed in a muffle furnace, heated to 450°C at a heating rate of 5°C / min, and calcined for 3 hours to obtain a calcined product, thus completing the load modification.

[0040] (4) Molding and activation: The calcined product was dried at 100°C for 5 h and pressed into blocks by a tablet press. The blocks were then crushed and granulated by a rolling process to form modified red mud particles. Finally, the modified red mud particles were calcined at 450°C for 4 h. Then, they were activated at 600°C for 3 h in a nitrogen atmosphere to obtain modified red mud.

[0041] (5) Biomass pretreatment: Crop straw is collected from farmland, crushed using a crusher, and then screened into biomass particles with a particle size of 2-5 mm. Metal impurities, stones, plastics and other non-biomass impurities in the biomass particles are removed, and the biomass particles are dried by drying in the sun or hot air.

[0042] (6) Biomass pyrolysis: The pretreated biomass particles and the modified red mud-based catalyst are uniformly mixed according to the modified red mud mass accounting for 10% of the total mass of the modified red mud and the biomass. The mixed material is placed in a pyrolysis reactor, and nitrogen is introduced into the pyrolysis reactor at a flow rate of 70 mL / min. The pyrolysis temperature is controlled to rise from room temperature to 550°C at a heating rate of 10°C / min and maintained at 550°C for 40 minutes. The biomass is pyrolyzed under the catalytic action of the modified red mud.

[0043] After the pyrolysis is completed, the mixed gas product is rapidly cooled by a condensation device to obtain a mixed liquid containing wood vinegar, tar, water, etc. The components of the wood vinegar are analyzed by a GC-MS instrument, and the organic ketone content is about 25%.

[0044] Comparative Example 1

[0045] This comparative example adopts the same method as Example 1 to carry out biomass pyrolysis, except that: in this comparative example, no modified red mud is added.

[0046] The components of wood vinegar were analyzed by GC-MS instrument, and the content of organic ketones was found to be 8%.

[0047] By comparing Example 1 with Comparative Example 1, it can be seen that after adding modified red mud, the yield of organic ketones is significantly improved, which proves that modified red mud has a significant promoting effect on increasing the yield of organic ketones in wood vinegar. By catalyzing the pyrolysis of biomass by modified red mud, the components of wood vinegar can be effectively regulated and the yield of the target components can be increased.

[0048] Comparative Example 2

[0049] This comparative example adopts the same method as Example 1 to carry out biomass pyrolysis, except that in this comparative example, the red mud is not loaded and modified, and unmodified red mud is directly added as a catalyst.

[0050] The components of wood vinegar were analyzed by GC-MS instrument, and the content of organic ketones was 15%.

[0051] By comparing Example 1 with Comparative Example 2, it can be seen that after adding modified red mud, the yield of organic ketones is increased again, proving that modified red mud has a more obvious promoting effect on increasing the yield of organic ketones in wood vinegar. Unmodified red mud has low catalytic activity, poor selectivity, many side reactions, insufficient thermal stability and lack of synergistic effect, resulting in a significant weakening of its effect on the generation of ketones in the process of biomass pyrolysis. 2 Modified red mud significantly promoted the production of ketones during biomass pyrolysis by improving catalytic activity, increasing acidic sites, inhibiting side reactions and enhancing thermal stability.

[0052] Example 2

[0053] This embodiment performs biomass pyrolysis according to the following steps:

[0054] (1) Red mud pretreatment: The red mud was dried at 200°C for 0.5 h to fully evaporate the free water therein. The dried red mud was placed in a ball mill with a ball-to-material ratio of 1:1 and ball-milled at a speed of 500 r / min for 3 h to obtain pulverized red mud powder. Finally, the red mud powder was calcined at 800°C for 0.5 h to complete the pretreatment of the red mud.

[0055] (2) Nanomaterial pretreatment: Select nano-silicon dioxide (SiO 2 ), calcined it in a muffle furnace at 400 °C for 1 h, and then the nano-SiO 2 Wash to neutrality and dry to complete the nanomaterial pretreatment.

[0056] (3) Load modification: The pretreated nano-SiO 2 Dispersed in deionized water, ultrasonically dispersed for 2 hours to form a suspension with a concentration of 5g / L. The pretreated red mud powder was added to the suspension. 2 The mass ratio was 50:1, stirred at room temperature for 2 h, and then heated and stirred in a water bath at 80 °C for 4 h. 2 The red mud was placed in a muffle furnace, heated to 600°C at a heating rate of 8°C / min, and calcined for 2h to obtain a calcined product, thus completing the load modification.

[0057] (4) Molding and activation: The calcined product was dried at 200°C for 0.5 h, pressed into shape by a tablet press, and then the block was crushed and subjected to a rolling granulation process to form modified red mud particles. The formed modified red mud particles were calcined at 600°C for 2 h, and then activated at 800°C for 1 h in a nitrogen atmosphere to obtain modified red mud.

[0058] (5) Biomass pretreatment: Crop straw is collected from farmland, crushed using a crusher, and then screened to produce biomass particles with a particle size of 1-6 mm. Non-biomass impurities such as metal impurities, stones, and plastics in the biomass particles are removed, and the biomass particles are dried by air drying or hot air drying.

[0059] (6) Biomass pyrolysis: The pretreated biomass particles and the modified red mud-based catalyst are uniformly mixed according to the modified red mud mass accounting for 20% of the total mass of the modified red mud and biomass. The mixed material is placed in a pyrolysis reactor, and nitrogen is introduced into the pyrolysis reactor at a flow rate of 100 mL / min. The pyrolysis temperature is controlled to rise from room temperature to 600°C at a heating rate of 50°C / min and maintained at 600°C for 10 minutes. The biomass is pyrolyzed under the catalytic action of the modified red mud.

[0060] In the wood vinegar component obtained by pyrolysis of biomass in this embodiment, the content of organic ketones is similar to that in Example 1, but slightly lower than that in Example 1.

[0061] Example 3

[0062] This embodiment performs biomass pyrolysis according to the following steps:

[0063] (1) Red mud pretreatment: The red mud was dried at 30°C for 10 h to fully evaporate the free water therein. The dried red mud was placed in a ball mill with a ball-to-material ratio of 1:1 and ball milled at a speed of 500 r / min for 3 h to obtain pulverized red mud powder. Finally, the red mud powder was calcined at 300°C for 10 h to complete the pretreatment of the red mud.

[0064] (2) Pretreatment of nanomaterials: Carbon nanotubes (CNTs) were selected, and a mixed liquid with a volume ratio of concentrated nitric acid: concentrated sulfuric acid = 1:3 was used as the reflux liquid. The CNTs were refluxed at 60° C. for 6 h, and then the CNTs were washed to neutrality and dried to complete the pretreatment of the CNTs.

[0065] (3) Load modification: The pretreated nano-CNTs were dispersed in deionized water and ultrasonically dispersed for 0.5 h to form a suspension with a concentration of 0.5 g / L. The pretreated red mud powder was added to the suspension with a mass ratio of red mud to nano-CNTs of 10:1. The mixture was stirred at room temperature for 2 h, and then heated and stirred in a 60 °C water bath for 8 h. The red mud loaded with nano-CNTs was placed in a muffle furnace, heated to 300 °C at a heating rate of 2 °C / min, and calcined for 5 h to obtain a calcined product, thus completing the load modification.

[0066] (4) Molding and activation: The calcined product was dried at 100°C for 5 h, pressed into shape by a tablet press, and then the block was crushed and subjected to a rolling granulation process to form modified red mud particles. The formed modified red mud particles were calcined at 300°C for 6 h, and then activated at 400°C for 5 h in a nitrogen atmosphere to obtain modified red mud.

[0067] (5) Biomass pretreatment: Crop straw is collected from farmland, crushed using a crusher, and then screened to produce biomass particles with a particle size of 1-6 mm. Non-biomass impurities such as metal impurities, stones, and plastics in the biomass particles are removed, and the biomass particles are dried by air drying or hot air drying.

[0068] (6) Biomass pyrolysis: The pretreated biomass particles and the modified red mud-based catalyst are uniformly mixed according to the modified red mud mass accounting for 5% of the total mass of the modified red mud and biomass. The mixed material is placed in a pyrolysis reactor, and nitrogen is introduced into the pyrolysis reactor at a flow rate of 50 mL / min. The pyrolysis temperature is controlled to rise from room temperature to 500°C at a heating rate of 1°C / min and maintained at 500°C for 180 minutes. The biomass is pyrolyzed under the catalytic action of the modified red mud.

[0069] The organic ketone content in the wood vinegar component obtained by pyrolysis of biomass in this embodiment is similar to that in Example 1.

[0070] Example 4

[0071] This embodiment performs biomass pyrolysis according to the following steps:

[0072] (1) Red mud pretreatment: The red mud was dried at 100°C for 5 h to fully evaporate the free water therein. The dried red mud was placed in a planetary ball mill with a ball-to-material ratio of 1.5:1 and ball-milled at a speed of 400 r / min for 5 h to obtain pulverized red mud powder. Finally, the red mud powder was calcined at 500°C for 6 h to complete the pretreatment of the red mud.

[0073] (2) Pretreatment of nanomaterials: Nano-CNTs were selected, and a mixed liquid with a volume ratio of concentrated nitric acid: concentrated sulfuric acid = 1:3 was used as the reflux liquid. The carbon nanotubes were refluxed at 70°C for 4 h, and then washed with deionized water until neutral and dried to complete the pretreatment of the carbon nanotubes.

[0074] (3) Load modification: The pretreated nano-CNTs were dispersed in deionized water and ultrasonically dispersed for 1.5 hours to form a suspension with a concentration of 3 g / L. The pretreated red mud powder was added to the suspension with a mass ratio of red mud to nano-CNTs of 30:1. The mixture was stirred at room temperature for 5 hours and then heated in a 65°C water bath for 6 hours. The red mud loaded with nano-CNTs was placed in a muffle furnace and heated to 400°C at a heating rate of 4°C / min. The mixture was calcined for 4 hours to obtain a calcined product, thus completing the load modification.

[0075] (4) Molding and activation: The calcined product was dried at 100 °C for 2 h, pressed into shape by an extruder, and then the block was crushed and subjected to a rolling granulation process to form modified red mud particles. The formed modified red mud particles were calcined at 500 °C for 3 h, and then activated at 700 °C for 4 h in an argon atmosphere to obtain modified red mud.

[0076] (5) Biomass pretreatment: Wood waste is collected from the forest area, crushed by a crusher, and then screened to obtain biomass particles with a particle size of 1-3 mm. Metal impurities, stones, plastics and other non-biomass impurities in the biomass particles are removed by air separation, and the biomass particles are dried by air drying or hot air drying.

[0077] (6) Biomass pyrolysis: The pretreated biomass particles and the modified red mud-based catalyst are uniformly mixed according to the modified red mud mass accounting for 4% of the total mass of the modified red mud and biomass. The mixed material is placed in a pyrolysis reactor, and nitrogen is introduced into the pyrolysis reactor at a flow rate of 50 mL / min. The pyrolysis temperature is controlled to rise from room temperature to 400°C at a heating rate of 35°C / min and maintained at 400°C for 30 minutes. The biomass is pyrolyzed under the catalytic action of the modified red mud.

[0078] After the pyrolysis is completed, the mixed gas product is rapidly cooled by a condensation device to obtain a mixed liquid containing wood vinegar, tar, water, etc. The components of the wood vinegar are analyzed by a GC-MS instrument, and the furan content is about 25%.

[0079] Comparative Example 3

[0080] This comparative example adopts the same method as Example 4 to carry out biomass pyrolysis, except that: in this comparative example, no modified red mud is added.

[0081] The components of wood vinegar were analyzed by GC-MS instrument, and the content of furans was found to be 8%.

[0082] By comparing Example 4 with Comparative Example 3, it can be seen that after adding modified red mud, the yield of furans is significantly improved, which proves that modified red mud has a significant promoting effect on increasing the yield of furans in wood vinegar. By catalyzing the pyrolysis of biomass with modified red mud, the components of wood vinegar can be effectively regulated and the yield of the target components can be increased.

[0083] Example 5

[0084] This embodiment performs biomass pyrolysis according to the following steps:

[0085] (1) Red mud pretreatment: The red mud was dried at 30°C for 10 h to fully evaporate the free water therein. The dried red mud was placed in a planetary ball mill and milled at a speed of 400 r / min for 5 h to obtain pulverized red mud powder. Finally, the red mud powder was calcined at 300°C for 10 h to complete the pretreatment of the red mud.

[0086] (2) Nanomaterial pretreatment: Select nano-SiO 2 , calcined it in a muffle furnace at 200 °C for 3 h, and then the nano-SiO 2 Wash to neutrality and dry to complete the nanomaterial pretreatment.

[0087] (3) Load modification: The pretreated nano-SiO 2 Dispersed in deionized water, ultrasonically dispersed for 0.5h to form a suspension with a concentration of 0.5g / L. The pretreated red mud powder was added to the suspension. 2 The mass ratio was 10:1, stirred at room temperature for 6 h, and then heated and stirred in a 60°C water bath for 4 h. 2 The red mud was placed in a muffle furnace, heated to 300°C at a heating rate of 2°C / min, and calcined for 5 hours to obtain a calcined product, thus completing the load modification.

[0088] (4) Molding and activation: The calcined product was dried at 30°C for 10 h, pressed into shape by a tablet press, and then the block was crushed and subjected to a rolling granulation process to prepare modified red mud particles. The formed modified red mud particles were calcined at 300°C for 6 h, and then activated at 400°C for 5 h in a nitrogen atmosphere to obtain modified red mud.

[0089] (5) Biomass pretreatment: Wood waste is collected from the forest area, crushed by a crusher, and then screened to obtain biomass particles with a particle size of 1-3 mm. Metal impurities, stones, plastics and other non-biomass impurities in the biomass particles are removed by air separation, and the biomass particles are dried by air drying or hot air drying.

[0090] (6) Biomass pyrolysis: The pretreated biomass particles and the modified red mud-based catalyst are uniformly mixed according to the modified red mud mass accounting for 2% of the total mass of the modified red mud and biomass. The mixed material is placed in a pyrolysis reactor, and nitrogen is introduced into the pyrolysis reactor at a flow rate of 50 mL / min. The pyrolysis temperature is controlled to rise from room temperature to 350°C at a heating rate of 1°C / min and maintained at 350°C for 180 minutes. The biomass is pyrolyzed under the catalytic action of the modified red mud.

[0091] The content of furan substances in the wood vinegar component obtained by pyrolysis of biomass in this embodiment is similar to that in Example 4.

[0092] Example 6

[0093] This embodiment performs biomass pyrolysis according to the following steps:

[0094] (1) Red mud pretreatment: The red mud was dried at 200°C for 0.5 h to fully evaporate the free water therein. The dried red mud was placed in a planetary ball mill with a ball-to-material ratio of 1.5:1 and ball-milled at a speed of 400 r / min for 5 h to obtain pulverized red mud powder. Finally, the red mud powder was calcined at 800°C for 0.5 h to complete the pretreatment of the red mud.

[0095] (2) Nanomaterial pretreatment: Select nano titanium dioxide (TiO 2 ), calcined it in a muffle furnace at 300 °C for 2 h, and then the nano-TiO 2 Wash to neutrality and dry to complete the nanomaterial pretreatment.

[0096] (3) Load modification: The pretreated nano-TiO 2 Dispersed in deionized water, ultrasonically dispersed for 2 hours to form a suspension with a concentration of 5g / L. The pretreated red mud powder was added to the suspension. 2 The mass ratio was 50:1, stirred at room temperature for 2 h, and then heated and stirred in a water bath at 80 °C for 4 h. 2 The red mud was placed in a muffle furnace, heated to 600°C at a heating rate of 8°C / min, and calcined for 2h to obtain a calcined product, thus completing the load modification.

[0097] (4) Molding and activation: The calcined product was dried at 200 °C for 0.5 h, pressed into blocks by a tablet press, and then crushed and granulated by a rolling process to form modified red mud particles. Finally, the formed modified red mud particles were calcined at 600 °C for 2 h, and then activated at 800 °C for 1 h under a nitrogen atmosphere to obtain modified red mud.

[0098] (5) Biomass pretreatment: Wood waste is collected from the forest area, crushed by a crusher, and then screened to obtain biomass particles with a particle size of 1-3 mm. Metal impurities, stones, plastics and other non-biomass impurities in the biomass particles are removed by air separation, and the biomass particles are dried by air drying or hot air drying.

[0099] (6) Biomass pyrolysis: The pretreated biomass particles and the modified red mud-based catalyst are uniformly mixed according to the modified red mud mass accounting for 3.5% of the total mass of the modified red mud and biomass. The mixed material is placed in a pyrolysis reactor, and nitrogen is introduced into the pyrolysis reactor at a flow rate of 50 mL / min. The pyrolysis temperature is controlled to rise from room temperature to 500°C at a heating rate of 50°C / min and maintained at 500°C for 10 minutes. The biomass is pyrolyzed under the catalytic action of the modified red mud.

[0100] The content of furan substances in the wood vinegar component obtained by pyrolysis of biomass in this embodiment is similar to that in Example 4.

[0101] Example 7

[0102] This embodiment performs biomass pyrolysis according to the following steps:

[0103] (1) Red mud pretreatment: The red mud was dried at 120°C for 4 hours to fully evaporate the free water therein. The dried red mud was placed in a ball mill with a ball-to-material ratio of 2:1 and ball-milled at a speed of 600 r / min for 4 hours to obtain pulverized red mud powder. Finally, the red mud powder was calcined at 500°C for 6 hours to complete the pretreatment of the red mud.

[0104] (2) Pretreatment of nanomaterials: Nano zinc oxide (ZnO) was selected and calcined in a muffle furnace at 250° C. for 2.5 h. The nano ZnO was then washed with deionized water until it was neutral and dried to complete the pretreatment of the nano material.

[0105] (3) Load modification: The pretreated nano ZnO was dispersed in deionized water and ultrasonically dispersed for 1.2 hours to form a suspension with a concentration of 2.5 g / L. The pretreated red mud powder was added to the suspension with a mass ratio of red mud to nano ZnO of 25:1. The mixture was stirred at room temperature for 3 hours, and then heated and stirred in a 75°C water bath for 5 hours. The nano ZnO-loaded red mud was placed in a muffle furnace, heated to 550°C at a heating rate of 6°C / min, and calcined for 3.5 hours to obtain a calcined product, thus completing the load modification.

[0106] (4) Molding and activation: The calcined product was dried at 150°C for 4 h, pressed into shape by a tablet press, and then the block was crushed and subjected to a rolling granulation process to form modified red mud particles. The formed modified red mud particles were calcined at 550°C for 3 h, and then activated at 750°C for 2 h in a nitrogen atmosphere to obtain modified red mud.

[0107] (5) Biomass pretreatment: Collect pruned fruit tree branches from the orchard, crush them using a crusher, and then screen out biomass particles with a particle size of 3-6 mm. Remove metal impurities in the biomass particles through magnetic separation, and dry the biomass particles by drying in the sun or hot air.

[0108] (6) Biomass pyrolysis: The pretreated biomass particles and the modified red mud-based catalyst are uniformly mixed according to the modified red mud mass accounting for 30% of the total mass of the modified red mud and the biomass. The mixed material is placed in a pyrolysis reactor, and nitrogen is introduced into the pyrolysis reactor at a flow rate of 80 mL / min. The pyrolysis temperature is controlled to rise from room temperature to 450°C at a heating rate of 30°C / min and maintained at 450°C for 60 minutes. The biomass is pyrolyzed under the catalytic action of the modified red mud.

[0109] After the pyrolysis is completed, the mixed gas product is rapidly cooled by a condensation device to obtain a mixed liquid containing wood vinegar, tar, water, etc. The wood vinegar components are analyzed by GC-MS instrument, and the content of phenolic substances is about 35%.

[0110] Comparative Example 4

[0111] This comparative example adopts the same method as Example 7 to carry out biomass pyrolysis, except that: in this comparative example, no modified red mud is added.

[0112] The components of wood vinegar were analyzed by GC-MS instrument, and the content of phenolic substances therein was detected to be 12%.

[0113] By comparing Example 7 with Comparative Example 4, it can be seen that after adding modified red mud, the yield of phenolic substances is significantly improved, which proves that modified red mud has a significant promoting effect on increasing the yield of phenolic substances in wood vinegar. By catalyzing the pyrolysis of biomass by modified red mud, the components of wood vinegar can be effectively regulated and the yield of the target component can be increased.

[0114] Example 8

[0115] This embodiment and embodiment 7 use the same method to perform biomass pyrolysis, the difference being that in this embodiment, the pyrolysis temperature is 400° C., and the modified red mud and biomass are uniformly mixed so that the mass of the modified red mud accounts for 25% of the total mass of the modified red mud and the biomass.

[0116] The content of phenolic substances in the wood vinegar component obtained by pyrolysis of biomass in this embodiment is similar to that in Example 7.

[0117] Example 9

[0118] In this example, biomass pyrolysis is carried out in the same way as in Example 7, except that: in this example, the pyrolysis temperature is 600 °C, and they are uniformly mixed according to the mass of the modified red mud accounting for 35% of the total mass of the modified red mud and biomass.

[0119] Among the components of the wood vinegar obtained by the biomass pyrolysis in this example, the content of phenolic substances is similar to that in Example 7.

[0120] To sum up, by adding modified red mud during the biomass pyrolysis process, the content ratios of organic ketones, furan substances, and phenolic substances in the components of the wood vinegar obtained by the biomass pyrolysis can be effectively increased, thereby improving the yield of the target components in the wood vinegar and the product value of the wood vinegar. At the same time, by carrying out load modification on the red mud and loading the nanomaterials on the surface of the red mud, the characteristics of the nanomaterials can be effectively utilized to promote the cracking of biomass molecules, improve the biomass pyrolysis efficiency, and improve the catalyst stability and the catalytic performance of the catalyst.

[0121] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A method for regulating wood vinegar components, characterized in that: The method comprises the following steps: (1) preparing modified red mud loaded with nanomaterials; (2) pre-treating biomass; (3) Using the modified red mud prepared in step (1) as a catalyst, catalyzing the pyrolysis of the biomass pretreated in step (2) under an inert gas protection environment.

2. The method according to claim 1, characterized in that: In the step (1), the specific steps of preparing the modified red mud loaded with nanomaterials include: S1: pre-treating red mud and nanomaterials respectively; S2: loading the nanomaterial pretreated in step S1 on the surface of the pretreated red mud to complete loading modification; S3: The red mud subjected to loading modification in step S2 is sequentially dried, molded, granulated, calcined, and activated to obtain modified red mud.

3. The method according to claim 2, characterized in that: In step S1, the specific process of pre-treating the red mud is: drying the red mud at 30-200° C. for 0.5-10 h, then ball-milling the dried red mud into red mud powder, and finally calcining the red mud powder at 300-800° C. for 0.5-10 h to complete the pre-treatment of the red mud.

4. The method according to claim 2, characterized in that: In the step S1, the specific process of pre-treating the nano material is as follows: the nano material includes nano metal oxide or carbon nanotube, the nano metal oxide is calcined at 200-400° C. for 1-3 hours, and then the nano metal oxide is washed to neutrality and dried to complete the pre-treatment of the nano metal oxide; a mixed liquid with a volume ratio of concentrated nitric acid: concentrated sulfuric acid = 1:3 is used as a reflux liquid, and the carbon nanotube is refluxed at 60-80° C. for 2-6 hours, and then the carbon nanotube is washed to neutrality and dried to complete the pre-treatment of the carbon nanotube.

5. The method according to claim 2, characterized in that: In the step S2, the specific process of load modification is: adding the pretreated nanomaterial into water, ultrasonically dispersing for 0.5-2h to obtain a suspension with a concentration of 0.5-5g / L, adding red mud to the suspension according to a mass ratio of red mud: nanomaterial = 10-50:1, and stirring for 2-6h at room temperature, then heating and stirring in a water bath at 60-80°C for 4-8h to further promote the combination of nanomaterial and red mud, and then heating the red mud loaded with nanomaterial to 300-600°C at a heating rate of 2-8°C / min, and calcining for 2-5h to complete the load modification.

6. The method according to claim 2, characterized in that: In the step S3, the loaded modified red mud is pressed into shape, and then the block is crushed and then subjected to a rolling granulation process to form modified red mud particles. Finally, the modified red mud particles are calcined at 300-600° C. for 2-6 hours and activated at 400-800° C. for 1-5 hours to obtain modified red mud.

7. The method according to claim 1, characterized in that: In the step (2), the specific process of biomass pretreatment includes: crushing and sieving the biomass to obtain biomass particles with a particle size of 1-6 mm, and then removing impurities, naturally drying in the sun or drying with hot air.

8. The method according to claim 1, characterized in that: In the step (3), the pyrolysis temperature is controlled to be 350-500° C., the mass of the modified red mud added is controlled to be less than 5% of the total mass of the modified red mud and the biomass, and the furanic substances in the wood vinegar are regulated to increase; The pyrolysis temperature is controlled to be 500-600°C, the mass of the modified red mud added is controlled to be 5%-20% of the total mass of the modified red mud and the biomass, and the ketone substances in the wood vinegar are regulated to increase; The pyrolysis temperature is controlled to be 400-600° C., the mass of the modified red mud added is controlled to be 25%-35% of the total mass of the modified red mud and the biomass, and the increase of phenolic substances in the wood vinegar is regulated.

9. The method according to claim 8, characterized in that: The pyrolysis time is 10-180 min.

10. The method according to claim 1, characterized in that: The inert gas includes nitrogen, argon, helium, ammonia, and carbon dioxide, and the flow rate of the inert gas is 50-100 mL / min.