Acid tar-assisted biomass particle wet grinding coupling baking treatment method

Abstract

The invention provides an acid tar-assisted biomass particle wet grinding coupling baking treatment method, which comprises the following steps: (1) carrying out crushing treatment on a biomass raw material to obtain biomass particles; (2) mixing the biomass particles with acidic tar, and carrying out wet grinding treatment to obtain ground biomass particles; (3) sequentially carrying out drying treatment, baking treatment and dry grinding treatment on the ground biomass particles to obtain biomass powder; acidic tar obtained by condensing baking flue gas generated in the baking treatment process is returned to be used for wet grinding treatment. According to the invention, the crushed biomass particles and the acidic tar obtained by condensing the baking flue gas are mixed and subjected to wet grinding, so that the grinding energy consumption can be greatly reduced, and the cyclic utilization of resources is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of biomass processing, and particularly relates to a method for biomass particle wet grinding coupled with baking treatment assisted by acid tar. BACKGROUND

[0002] The existing biomass particle grinding technology has the following problems: 1. The biomass particles are hard in texture, and when directly entering the coal mill for grinding, the energy consumption of the coal mill increases significantly. 2. The conventional disposal method is to directly blend and burn the granulated biomass particles, which does not effectively pretreat the biomass particles, resulting in low grinding efficiency and high energy consumption. 3. In the grinding process, the internal components such as cellulose and hemicellulose of the biomass have complex structures, and the conventional grinding method is difficult to break the structure, further increasing the grinding difficulty and energy consumption.

[0003] CN118454815A discloses a biomass particle material processing and grinding equipment and process, which comprises a conveying drive motor, a conveying mechanism connected to one end of the conveying drive motor, and an inlet provided on the conveying mechanism, a processing cylinder with an upper end side in communication with the other end of the conveying mechanism, and an outlet on the side of the lower end, two symmetrical grinding wheels rotatably connected to the side wall of the grinding cylinder, a grinding disc provided at the lower end of the grinding cylinder and fixedly connected to the processing cylinder, and having a plurality of through holes on the surface, a washing cylinder provided below the grinding disc and fixedly connected to the central shaft and slidingly connected to the processing cylinder, and having a water outlet on the surface. When processing long fiber biomass raw materials, the equipment prevents the raw materials from sticking and clogging, improves the grinding efficiency, optimizes the particle size distribution, and enhances the stability and reliability of the equipment.

[0004] CN220657823U discloses a grinding equipment for biomass particle fuel processing, which comprises a tank body, a rotating shaft provided in the tank body, a first motor connected to the top of the rotating shaft, a first grinding disc provided on the middle part of the rotating shaft, a second grinding disc provided on the bottom of the rotating shaft, a grinding sleeve provided at the bottom of the tank body and having a bottom extending out of the tank body, and the grinding sleeve being sleeved on the first grinding disc and the second grinding disc. By controlling the relative rotation between the first grinding disc, the second grinding disc and the grinding sleeve, the raw materials can be fully ground, and the use effect is improved.

[0005] CN106520247A discloses a carbonized treated fiber biomass fuel particle, which is composed of the following raw materials in parts by weight: eucalyptus bark 45-52 parts, pine branches 36-40 parts, rice straw 25-40 parts, cassava stem 30-36 parts, corn straw 25-32 parts, sugarcane residue 15-24 parts, adhesive 9-18 parts, white stone powder 4-8 parts, kyanite 12-15 parts. The biomass raw material is subjected to anaerobic fermentation treatment, so that the relative content of hemicellulose and cellulose in the biomass raw material is reduced, the relative content of lignin is increased, and the volatile content is reduced, thereby improving the combustion efficiency of the biomass fuel. Through the mixing of the biomass raw material and the combustion improver, the combustion efficiency and heat energy of the biomass fuel are improved.

[0006] However, the above-mentioned biomass particle grinding device and method still have problems of high preparation cost and high energy consumption in the grinding process. SUMMARY

[0007] In view of the problems in the prior art, the present application provides a method for biomass particle wet grinding coupled with baking treatment assisted by acid tar, which mixes the biomass particles after crushing treatment with acid tar obtained by condensing the baking flue gas, so as to greatly reduce the grinding energy consumption. The biomass particles after grinding are sequentially subjected to drying treatment, baking treatment and dry grinding treatment, which effectively solves the problem of difficult crushing of biomass blending combustion, improves the blending combustion efficiency, and is suitable for wide application and promotion.

[0008] To achieve this purpose, the present application adopts the following technical solutions:

[0009] The present application provides a method for biomass particle wet grinding coupled with baking treatment assisted by acid tar, which comprises the following steps:

[0010] (1) biomass raw material is subjected to crushing treatment to obtain biomass particles;

[0011] (2) the biomass particles are mixed with acid tar for wet grinding treatment to obtain biomass particles after grinding;

[0012] (3) the biomass particles after grinding are sequentially subjected to drying treatment, baking treatment and dry grinding treatment to obtain biomass powder; the acid tar obtained by condensing the baking flue gas generated in the baking treatment is returned to step (2) for wet grinding treatment.

[0013] The acid tar assisted biomass particle wet grinding coupled baking treatment method disclosed by the application first performs crushing treatment on the biomass raw material, so that the particle size is smaller, and the subsequent baking treatment is easier; then the water-soluble acid tar is added in the wet grinding process, which can achieve grinding and demineralization, and at a higher temperature in the wet grinding, the acid substance can promote the hydrolysis of cellulose, hemicellulose and the like, and reduce the grinding energy consumption; after grinding, the biomass particles are sequentially subjected to drying treatment, baking treatment and dry grinding treatment, and biomass powder is obtained, which can be used for furnace blending combustion, effectively solving the problems of difficult crushing and high grinding energy consumption of biomass blending combustion, and improving the grinding efficiency and quality.

[0014] The acid tar in step (2) is obtained from the tar produced after condensation of the subsequent biomass particle baking flue gas, which is mainly water plus small molecular acid substances, with a pH of 2.5-3.5, forming a water-soluble acid tar.

[0015] The acid tar assisted biomass particle wet grinding coupled baking treatment method disclosed by the application adopts the sequence of wet grinding treatment first and then baking treatment, breaking the limitation of the particle size of biomass particles in traditional baking treatment; the acid tar obtained by condensation treatment of the baking flue gas is used for wet grinding treatment, realizing the recycling of resources, reducing the production cost and reducing environmental pollution.

[0016] The biomass particle coke after baking treatment is sent to a pulverizer for dry grinding treatment to prepare biomass powder meeting the requirements of furnace blending combustion. The grinding parameters of the pulverizer can be accurately controlled according to the properties of the biomass particles and the particle size requirements of the powder, to ensure that the quality and performance of the final biomass powder meet the blending combustion standards. In the whole process, the material conveying equipment such as pipelines and conveyors are closely connected to realize continuous and stable treatment of the biomass particles. At the same time, the automatic control system can be used to monitor and control the operating parameters (such as temperature, flow, speed, etc.) of each equipment in real time, to ensure efficient and stable operation of the process.

[0017] The acid tar assisted biomass particle wet grinding coupled baking treatment method disclosed by the application is suitable for the treatment of various existing biomass raw materials, such as corn stalks, wheat stalks, rice husks, corn cobs, cotton stalks, and sugarcane residues.

[0018] Preferably, the particle size of the biomass particles in step (1) is 10-20 mm, for example, it can be 10 mm, 12 mm, 14 mm, 16 mm, 18 mm or 20 mm, etc., but it is not limited to the listed values, and other values not listed in this range are also applicable.

[0019] The present invention preferably produces biomass pellets with a particle size of 10-20 mm after crushing, which is beneficial for more thorough and efficient subsequent drying and baking processes. During the crushing process, in order to achieve the required particle size range, those skilled in the art can reasonably adjust the speed and crushing intensity of the crusher according to the properties of the biomass raw materials.

[0020] Preferably, the mass ratio of biomass pellets to acid tar in step (2) is 1:0.1 to 1:0.3, for example, it can be 1:0.1, 1:0.15, 1:0.2, 1:0.22, 1:0.25 or 1:0.3, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0021] The present invention preferably uses a mass ratio of biomass pellets to acid tar of 1:0.1 to 1:0.3, which can achieve both grinding and demineralization, thus significantly reducing grinding efficiency.

[0022] Preferably, the pH of the acidic tar in step (2) is 2.5 to 3.5, for example, it can be 2.5, 2.7, 2.9, 3.1, 3.3 or 3.5, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0023] Preferably, the temperature of the wet milling process in step (2) is 60 to 80°C, for example, 60°C, 65°C, 68°C, 72°C, 76°C or 80°C, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0024] The present invention preferably uses a wet milling temperature of 60-80°C, which effectively promotes the hydrolysis of cellulose and hemicellulose, reduces grinding energy consumption, and simultaneously achieves demineralization, thereby improving grinding efficiency and quality.

[0025] Preferably, the particle size of the biomass particles after grinding in step (2) is 1 to 3 mm, for example, it can be 1 mm, 1.5 mm, 2 mm, 2.2 mm, 2.5 mm or 3 mm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0026] Preferably, the drying process in step (3) involves introducing a temperature of 120 to 150°C into the drying device. For example, it can be 120°C, 125°C, 130°C, 135°C, 140°C, or 150°C, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0027] Flow rate is 100-200 m³ 3 / h of air, for example, could be 100m 3 / h, 120m 3 / h, 140m 3 / h, 160m 3 / h, 180m 3 / h or 200m 3 / h, etc., but not limited to the listed values; other unlisted values ​​within this range also apply.

[0028] Preferably, the drying process of this invention involves introducing a flow of air into a drying device at a temperature of 120–150°C and a flow rate of 100–200 m³ / h. 3 The air supply is provided at a rate of / h to ensure uniform drying and good drying effect, while avoiding over-drying that could alter the properties of the biomass pellets.

[0029] Preferably, the air is generated by heat exchange between low-temperature air at a temperature of 20-25°C and baking flue gas during condensation heat exchange treatment. For example, it can be 20°C, 21°C, 22°C, 23°C, 24°C or 25°C, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0030] Preferably, the air after drying in step (3) enters the wet grinding process to recover water from the air.

[0031] Preferably, the baking temperature in step (3) is 240 to 260°C, for example, 240°C, 245°C, 250°C, 253°C, 258°C or 260°C, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0032] The present invention does not impose a detailed limit on the baking time, but can adjust it reasonably according to the properties of the biomass pellets.

[0033] As a preferred technical solution of the present invention, the method includes the following steps:

[0034] (1) After the biomass raw material is crushed, biomass particles with a particle size of 10-20 mm are obtained;

[0035] (2) The biomass pellets are mixed with acidic tar with a pH of 2.5 to 3.5 at a mass ratio of 1:0.1 to 1:0.3 and wet-milled at a temperature of 60 to 80°C to obtain ground biomass pellets with a particle size of 1 to 3 mm.

[0036] (3) The ground biomass particles are sequentially dried, baked at a temperature of 240-260℃ and dry ground to obtain biomass powder; the baking flue gas generated during the baking process is condensed and the resulting acidic tar is returned to step (2) for wet grinding.

[0037] The drying process involves introducing a stream of water into a drying device at a temperature of 120–150°C and a flow rate of 100–200 m³ / h. 3 / h of air; the air is generated by heat exchange between low-temperature air at a temperature of 20-25℃ and baking flue gas in a condensation heat exchange process; the air after drying treatment enters the wet grinding process to recover water from the air.

[0038] Compared with the prior art, the present invention has at least the following beneficial effects:

[0039] (1) The method of wet grinding and baking of biomass particles with acid tar assisted by the present invention effectively reduces the energy consumption in the grinding process of biomass particles through crushing and acid tar assisted wet grinding.

[0040] (2) The method of wet grinding coupled with baking of biomass particles with acid tar provided by the present invention makes the biomass particles easier to grind deeply after baking, and can produce biomass powder with finer particle size and better uniformity, which can greatly improve the co-firing effect and combustion efficiency.

[0041] (3) The method of wet grinding and baking of biomass pellets with acid tar assisted by the present invention recycles acid tar, reduces tar emissions, reduces the risk of environmental pollution, and avoids the problem of tar waste disposal in traditional treatment methods.

[0042] (4) The method of wet grinding and roasting of biomass particles with acid tar assisted by the present invention reduces the energy consumption and cost of biomass co-firing, improves its application value and economy in the energy field, and is conducive to promoting the development and utilization of biomass energy. Attached Figure Description

[0043] Figure 1 This is a schematic flowchart of the method for wet milling and coupled baking of biomass pellets with acid tar assisted by Embodiment 1 of the present invention. Detailed Implementation

[0044] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0045] The present invention will now be described in further detail. However, the examples described below are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0046] Example 1

[0047] This embodiment provides a method for wet milling and roasting of biomass pellets with acid tar assistance, the process flow diagram of which is shown below. Figure 1 As shown. The method includes the following steps:

[0048] (1) After the biomass raw material corn straw is crushed, biomass pellets with a particle size of 15 mm are obtained;

[0049] (2) The biomass pellets are mixed with acidic tar with pH 2.8 at a mass ratio of 1:0.2 and wet-milled at a temperature of 70°C to obtain ground biomass pellets with a particle size of 1.3 mm.

[0050] (3) The ground biomass particles are sequentially dried, baked at 250°C, and dry ground to obtain biomass powder; the baking flue gas generated during the baking process is condensed and the resulting acidic tar is returned to step (2) for wet grinding.

[0051] The drying process involves introducing a flow rate of 150 m³ / h into a drying device at a temperature of 130°C. 3 / h of air; the air is generated by heat exchange between low-temperature air at 25°C and baking flue gas in a condensation heat exchange process; the air after drying enters a wet grinding process to recover water from the air.

[0052] Example 2

[0053] This embodiment provides a method for wet milling and roasting of biomass pellets with acid tar assistance, the method comprising the following steps:

[0054] (1) After crushing, the biomass raw material wheat straw is used to obtain biomass pellets with a particle size of 10 mm.

[0055] (2) The biomass pellets are mixed with acidic tar with pH 2.5 at a mass ratio of 1:0.3 and wet-milled at a temperature of 60°C to obtain ground biomass pellets with a particle size of 1 mm.

[0056] (3) The ground biomass particles are sequentially dried, baked at 240°C, and dry ground to obtain biomass powder; the acidic tar obtained by condensing the baking flue gas generated during the baking process is returned to step (2) for wet grinding.

[0057] The drying process involves introducing a flow of water at a temperature of 150°C and a flow rate of 100 m³ / h into the drying device. 3 / h of air; the air is generated by heat exchange between low-temperature air at 20°C and baking flue gas in a condensation heat exchange process; the air after drying treatment enters the wet grinding process to recover water from the air.

[0058] Example 3

[0059] This embodiment provides a method for wet milling and roasting of biomass pellets with acid tar assistance, the method comprising the following steps:

[0060] (1) After the biomass raw material cotton straw is crushed, biomass pellets with a particle size of 20 mm are obtained;

[0061] (2) The biomass pellets are mixed with acidic tar with pH 3.5 at a mass ratio of 1:0.1 and wet-milled at a temperature of 80°C to obtain ground biomass pellets with a particle size of 3 mm.

[0062] (3) The ground biomass particles are sequentially dried, baked at 260°C, and dry ground to obtain biomass powder; the baking flue gas generated during the baking process is condensed and the resulting acidic tar is returned to step (2) for wet grinding.

[0063] The drying process involves introducing a flow of water at a temperature of 120°C and a flow rate of 200 m³ / h into the drying device. 3 / h of air; the air is generated by heat exchange between low-temperature air at 22°C and baking flue gas in a condensation heat exchange process; the air after drying enters a wet grinding process to recover water from the air.

[0064] Example 4

[0065] This embodiment provides a method for wet milling and roasting of biomass pellets with acid tar assistance, the method comprising the following steps:

[0066] (1) After the biomass raw material corn straw is crushed, biomass pellets with a particle size of 18 mm are obtained;

[0067] (2) The biomass pellets are mixed with acidic tar with pH 2.58 at a mass ratio of 1:0.15 and wet-milled at a temperature of 67°C to obtain ground biomass pellets with a particle size of 1.7 mm.

[0068] (3) The ground biomass particles are sequentially dried, baked at 248°C, and dry ground to obtain biomass powder; the baking flue gas generated during the baking process is condensed and the resulting acidic tar is returned to step (2) for wet grinding.

[0069] The drying process involves introducing a flow rate of 175 m³ / h into a drying device at a temperature of 135°C. 3 / h of air; the air is generated by heat exchange between low-temperature air at 23°C and baking flue gas in a condensation heat exchange process; the air after drying enters a wet grinding process to recover water from the air.

[0070] The acid tar-assisted wet milling and roasting method for biomass pellets provided in Examples 1-4 effectively reduces energy consumption during the biomass pellet grinding process by combining crushing and acid tar-assisted wet milling. It also recycles the acid tar, reducing tar emissions and the risk of environmental pollution, and further reduces the energy consumption and cost of biomass co-firing.

[0071] Example 5

[0072] This embodiment provides a method for wet milling and roasting of biomass pellets assisted by acid tar. Except for the wet milling temperature of 50°C, the method is the same as that in Embodiment 1.

[0073] In this embodiment, the low temperature of wet milling results in slow hydrolysis of cellulose and hemicellulose, poor demineralization, reduced grinding efficiency, and high grinding energy consumption.

[0074] Example 6

[0075] This embodiment provides a method for wet milling and roasting of biomass pellets assisted by acid tar. Except for the wet milling temperature of 90°C, the method is the same as that in Embodiment 1.

[0076] Because the wet grinding process in this embodiment is carried out at a high temperature, it releases volatile organic compounds such as formaldehyde and acetic acid, requiring additional waste gas treatment; it also increases energy consumption and treatment costs.

[0077] Example 7

[0078] This embodiment provides a method for wet milling and roasting of biomass pellets with acid tar assistance. Except for the roasting temperature of 230°C, the method is the same as that in Embodiment 1.

[0079] In this embodiment, due to the low baking temperature, the volatiles are not fully decomposed, resulting in a higher tar yield. However, this leads to poor quality biomass pellets obtained from the roasting process, which are easy to burn but also prone to slagging.

[0080] Example 8

[0081] This embodiment provides a method for wet milling and roasting of biomass pellets with acid tar assistance. Except for the roasting temperature of 270°C, the method is the same as that in Embodiment 1.

[0082] In this embodiment, the high temperature of the baking process causes the tar to partially decompose into small molecule gases (such as CH4 and CO), resulting in a decrease in the amount of acidic tar obtained from condensation, which in turn affects the wet milling process.

[0083] In summary, the acid tar-assisted wet milling coupled with roasting method for biomass pellets provided by this invention involves crushing the biomass raw material to reduce its particle size, making it easier for subsequent roasting. Then, acid tar is added to wet mill the crushed biomass pellets, achieving thorough grinding and demineralization, thus reducing grinding energy consumption. After grinding, the biomass pellets undergo drying, roasting, and dry milling sequentially to obtain biomass powder, which can be used for co-firing in the furnace, effectively solving the problems of difficult crushing and high energy consumption in grinding biomass co-firing. Furthermore, the acid tar obtained from the roasting flue gas after condensation is used for wet milling, achieving resource recycling and reducing environmental pollution.

[0084] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for wet milling and coupled roasting of biomass pellets with acid tar assistance, characterized in that, The method includes the following steps: (1) Biomass raw materials are crushed to obtain biomass pellets; (2) The biomass pellets are mixed with acidic tar and wet-milled to obtain ground biomass pellets. (3) The ground biomass particles are sequentially dried, baked and dry ground to obtain biomass powder; the baking flue gas generated during the baking process is condensed and the resulting acidic tar is returned to step (2) for wet grinding.

2. The method according to claim 1, characterized in that, The biomass particles in step (1) have a particle size of 10-20 mm.

3. The method according to claim 1 or 2, characterized in that, The mass ratio of biomass pellets to acid tar in step (2) is 1:0.1 to 1:0.

3.

4. The method according to any one of claims 1 to 3, characterized in that, The pH of the acidic tar in step (2) is 2.5 to 3.

5.

5. The method according to any one of claims 1 to 4, characterized in that, The temperature of the wet milling process in step (2) is 60-80℃.

6. The method according to any one of claims 1 to 5, characterized in that, The particle size of the biomass particles after grinding in step (2) is 1-3 mm.

7. The method according to any one of claims 1 to 6, characterized in that, The drying process described in step (3) involves introducing a flow of water at a temperature of 120–150°C and a flow rate of 100–200 m³ / h into the drying device. 3 / h of air.

8. The method according to claim 7, characterized in that, The air is generated by heat exchange between low-temperature air (20-25°C) and baking flue gas during condensation heat exchange treatment.

9. The method according to any one of claims 1 to 8, characterized in that, The air dried in step (3) enters the wet grinding process to recover water from the air.

10. The method according to any one of claims 1 to 9, characterized in that, The baking temperature in step (3) is 240-260℃.

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