CN114106901A

CN114106901A - Preparation method of biomass fuel and biomass fuel

Info

Publication number: CN114106901A
Application number: CN202111256282.8A
Authority: CN
Inventors: 侯鹏; 李笋; 吕胜建; 刘成荣
Original assignee: Csic Shanghai New Energy Co ltd
Current assignee: Csic Shanghai New Energy Co ltd
Priority date: 2021-10-27
Filing date: 2021-10-27
Publication date: 2022-03-01

Abstract

The application discloses a preparation method of biomass fuel and the biomass fuel. The preparation method of the biomass fuel is used for producing the fuel of the biomass circulating fluidized bed boiler, and comprises the step of uniformly blending animal wastes, yellow straws, small-variety fuels and forest wood fuels according to a proportion, wherein the blending amount of the animal wastes is 15-58 wt%, the blending amount of the yellow straws is 10-58 wt%, the blending amount of the small-variety fuels is 4-32 wt%, and the blending amount of the forest wood fuels is 0-10 wt%. The method can obtain the biomass fuel which is uniformly blended, and the biomass fuel which is reasonably controlled and blended and is mixed with the animal waste can be stably combusted and can be fully utilized by the circulating fluidized bed boiler.

Description

Preparation method of biomass fuel and biomass fuel

Technical Field

The application relates to the technical field of biomass fuels, in particular to a preparation method of a biomass fuel and the biomass fuel.

Background

Modern farms develop gradually towards large-scale and intensive directions. In the cultivation process, in order to control morbidity and improve yield, a farm often uses a feed additive. Besides heavy metals, the feces of livestock and poultry in the farm also contains a large amount of pathogenic bacteria and parasitic ova. The efficient and harmless treatment of a large amount of excrement becomes a troublesome problem.

In recent years, biomass direct-fired power plants are developed vigorously, a large amount of agricultural and forestry wastes are recycled, and outstanding contribution is made in the aspect of beautifying country construction. At present, main fuel varieties of biomass direct-fired power plants are bark, wood chips, straws, rice hulls, brush wood fuel and the like. With the low enthusiasm of the building industry and the enhancement of the policy of environmental protection, the yield of the waste of bark, wood chips and brush wood is greatly reduced year by year. The total amount of rice hulls, peanut hulls and the like is limited, and the price is high. And the more biomass power plants are built, the more fuel competition is intensified. In order to ensure the sustainable development of the biomass power plant, a plurality of practitioners in the industry aim the fuel of the biomass power plant to develop yellow straws in a key direction. At present, the bottleneck of storage and efficient crushing of rice straws and wheat straws is also broken through. However, the storage work of the crop straws is severely restricted by weather and topography, the uncertainty is large, and the stable operation of the biomass power plant is influenced.

Therefore, the application provides a technical means that biomass fuel evenly mixes and joins in marriage reasonable the blending of agricultural wastes such as excrement and urine and yellow straw of plant, can solve the excrement and urine environmental pollution problem of plant, also helps biomass power plant's steady operation.

Disclosure of Invention

The biomass fuel and the preparation method thereof can reasonably control and mix various fuels, can fully utilize the prepared biomass fuel by a circulating fluidized bed boiler, can realize stable combustion by mixing the biomass fuel with animal excrement, and can save the operation cost of a biomass power plant and stabilize the fuel supply of the biomass power plant by co-combusting the animal excrement.

The application provides a preparation method of biomass fuel, which comprises the steps of blending animal waste, yellow straws, small-variety fuel and forest wood fuel in proportion to obtain the biomass fuel;

the biomass fuel comprises 15-58 wt% of animal wastes, 10-58 wt% of yellow straws, 4-32 wt% of small-variety fuels and 0-10 wt% of forest fuels.

The biomass fuel is used as the fuel of a biomass circulating fluidized bed boiler.

Optionally, in some embodiments of the present application, the preparation method includes the following steps:

directly carrying out sectional shearing type crushing on the yellow straws according to the mixing amount to obtain yellow straw crushed materials with the length less than or equal to 7cm, wherein the section knife edges of the crushed materials are neat, and the straws have no adhesion or agglomeration;

crushing the forest fuel after deironing to obtain a forest fuel crushed material with the length of less than or equal to 10cm, wherein the thickness and the width of the forest fuel crushed material are less than or equal to 7 cm;

and paving the yellow straw crushed material, the animal manure, the small variety fuel and the forest wood fuel crushed material layer by layer according to the mixing amount to obtain a fuel pile, and uniformly mixing to obtain the biomass fuel.

Optionally, in some embodiments of the present application, in the layer-by-layer laying process, a layer of the yellow straw broken material, a layer of the animal waste, a layer of the small-grade fuel and a layer of the forest-based fuel broken material form a fuel layer combination unit, and the fuel above the three fuel layer combination units is laid.

Alternatively, in some embodiments of the present application, after said layer-by-layer laying, a fuel pile is obtained presenting a band shape. The fuel pile comprises an animal excrement layer, a yellow straw layer, a small-variety fuel layer and a forest wood fuel layer. Further, at least one yellow straw layer, a small variety fuel layer and/or a forest wood fuel layer are arranged between the animal excrement layers.

Optionally, in some embodiments of the present application, during the layer-by-layer laying, each fuel is laid in a single layer, and the same fuel is not laid continuously.

Further, in the preparation method, a fuel layer assembly unit may be composed of a layer of animal excrements, a layer of yellow straw, a layer of small-breed fuel and a layer of forest-wood fuel, and the fuel layer assembly unit may be used as a repeating unit. The sequence of the animal excrement layer, the yellow straw layer, the small variety fuel layer and the forest wood fuel layer in each repeating unit is independently limited, namely the sequence of the fuel layers in each repeating unit and the other repeating unit can be the same or different.

For example, the layer-by-layer laying process may be specifically: sequentially laying three fuel layer combination units, namely 12 layers, layer by layer according to the sequence of yellow straws, small-variety fuels, animal wastes and forest wood fuels; it is also possible to lay up to four fuel layer assembly units, i.e. 16 layers; even more layers, over four fuel layer combining units. The specific number of layers to be laid can be selected according to the space of the actual blending field.

For example, the layer-by-layer laying process may be specifically: sequentially laying three fuel layer combined units, namely 12 layers, layer by layer according to the sequence of yellow straws, small-grade fuels, forest and wood fuels, animal wastes, yellow straws, small-grade fuels, animal wastes and forest and wood fuels; more fuel layer assembly units can also be laid on the basis of the above.

For example, the layer-by-layer laying process may be specifically: sequentially laying three fuel layer combination units layer by layer according to the sequence of yellow straws, forest wood fuel, small-variety fuel, animal manure, yellow straws, small-variety fuel, forest wood fuel, animal manure, yellow straws, animal manure, forest wood fuel and small-variety fuel; more fuel layer assembly units can also be laid on the basis of the above.

Optionally, in some embodiments of the present application, the yellow straw broken material is used as a first layer of paving material, on the basis of which the animal waste, the small variety fuel and the forest wood fuel broken material are not repeatedly and optionally paved to form a multi-layer stacking material, the multi-layer stacking material is repeatedly paved for a plurality of times, and the biomass fuel is obtained after mixing. Wherein "laying layer by layer" means: animal waste, small-variety fuel or forest wood fuel broken materials can be paved on the basis of the yellow straw broken materials, and each layer is paved by adopting different fuel types. "non-repeating" laying refers to: in a multi-layer stack, the fuel types of two adjacent fuel layers are different. "optional" placement refers to: except the first yellow straw crushing layer, the fuel type of each fuel layer can be any one selected from animal excrement, small-class fuel and forest fuel crushing material. The three laying rules need to be satisfied simultaneously.

Alternatively, in some embodiments herein, the animal manure may be incorporated at 15 wt%, 19 wt%, 25 wt%, 27 wt%, 30 wt%, 35 wt%, 40 wt%, 44 wt%, 47 wt%, 50 wt%, 52 wt% or 58 wt%. The amount of the yellow straw can be 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 33 wt%, 37 wt%, 39 wt%, 41 wt%, 45 wt%, 46 wt%, 49 wt%, 54 wt%, 55 wt% or 58 wt%. The blend amount of the small grade fuel may be 4 wt%, 6 wt%, 11 wt%, 13 wt%, 14 wt%, 16 wt%, 17 wt%, 19 wt%, 24 wt%, 30 wt%, or 32 wt%. The blending amount of the forest wood fuel is 0 wt%, 1 wt%, 2 wt%, 4 wt%, 5 wt%, 6 wt%, 9 wt% or 10 wt%.

Optionally, in some embodiments of the present application, the animal manure is blended in an amount of 25-50 wt%, the yellow straw is blended in an amount of 20-45 wt%, the small fuel is blended in an amount of 12-28 wt%, and the forest wood fuel is blended in an amount of 2-6 wt%.

Optionally, in some embodiments of the present application, the animal manure includes, but is not limited to, one or more of chicken manure, cattle manure, sheep manure, and duck manure. Preferably, the animal manure is chicken manure. Further, the animal manure is poultry manure or herbivore manure of a farm. The poultry manure comprises chicken manure, duck manure and the like. When the large poultry farm is used for indoor breeding, the chicken coop is usually subjected to water absorption and drying by using rice husks, wood chips and other gasket materials. The poultry manure fuel at the farm is actually a mixture of poultry manure and washer rice hulls/sawdust. In addition, the feed ingested by the chicken cannot be completely digested and absorbed, about 40 to 70 percent of nutrients are discharged out of the body, and the chicken manure fuel has more organic matters, high volatile matters, easy ignition and easy burnout. After being mixed with other fuel components, the fuel can play a role in supporting combustion and assisting stable combustion. The domestic nomadic nationality has long utilized the feces of animals such as cattle, sheep, horses and the like as the fuel for burning fire. The excrement of herbivores such as cattle and sheep also contains a large amount of plant fibers and nutrients, and can be used as fuel. The chicken manure comprises a mixture of bedding rice hulls in a chicken house and excrement excreted by the raised chickens. Similarly, the duck manure comprises a mixture of duck shed liner rice hulls and excrement discharged by the raised ducks. The rice hulls on the gaskets are often stained with poultry manure, and can be mixed with the poultry manure without special treatment.

Those of ordinary skill in the art know that the difficulty of incineration of chicken manure is much higher than other biomass fuels (straw, etc.). But this application adopts the chicken manure as fuel, and the blending amount of chicken manure even reaches 58%, and the cost of chicken manure is low, can not only supply the breach of fuel quantity, can also nuisanceless treatment plant's excrement and urine.

Optionally, in some embodiments of the present application, the yellow straw is comprised primarily of one or more of rice straw, wheat straw, and corn straw; more than two kinds of yellow straws are directly mixed and crushed together according to the proportion in the crushing process, and the uniform mixing before the blending of the yellow straws is firstly realized.

Optionally, in some embodiments of the present application, the small variety of fuel comprises a shell fuel.

Optionally, in some embodiments of the present application, the shell-based fuel comprises one or more of rice hulls, peanut hulls, melon seed hulls, fruit hulls, pine cone hulls, and wheat bran.

Optionally, in some embodiments of the present application, the forest wood-based fuel comprises one or more of old furniture and abandoned building templates.

Optionally, in some embodiments of the present application, the forest wood fuel comprises one or more of brushwood, bark, bamboo chips, bamboo shavings, and shrubs. The forest wood fuel of this application need pass through independent crushing process in advance, behind the formation fuel heap, stirs the mixture again.

In the application, the yellow straw has small density, fluffiness and large volume, and the relative density of other kinds of fuel is large. The heat value and the combustion characteristic of each fuel are different, and after being uniformly mixed, the chicken manure, the forest wood fuel and other small-variety fuels are uniformly distributed among the yellow straw fuels to form the mixed fuel with uniform texture. The fluffy volume of the yellow straw can ensure the oxygen supply of the initial combustion of the mixture. The fuel with high volatile component is burnt first to form pre-drying and pre-ignition of the fuel with low volatile component. Each fuel in the biomass fuel can form a combustion cascade reaction, so that the combustion process is accelerated, the combustion efficiency and the combustion stability are improved, the energy contained in the biomass fuel is fully utilized, and more energy can be provided for a circulating fluidized bed boiler and a biomass fuel power plant. In addition, the materials are low in price, wide in raw material source and easy to obtain, the operation cost can be lowered, the fuel supply is stabilized, the problem of efficient and harmless treatment of the excrement of the farm can be solved, and the maximization of economic benefits and social benefits is realized.

The application provides a preparation method of fuels such as animal waste, yellow straws, small-variety fuels, forest wood fuels and the like. Further, the preparation method can also be used for mixing and blending other biomass fuels.

Correspondingly, the application also provides the biomass fuel obtained by the preparation method of the biomass fuel. The biomass fuel is suitable for being used in a biomass circulating fluidized bed boiler. The biomass fuel obtained by the application is particularly suitable for a biomass direct-fired power plant taking biomass materials as fuel.

Optionally, in some embodiments of the present application, the biomass fuel comprises: 15-58 wt% of animal waste, 10-58 wt% of yellow straw, 4-32 wt% of small-variety fuel and 0-10 wt% of forest fuel.

Optionally, in some embodiments of the present application, in the biomass fuel, the animal waste is 25 to 50 wt%, the yellow straw is 20 to 45 wt%, the minor-variety fuel is 12 to 28 wt%, and the forest-wood fuel is 2 to 8 wt%.

Optionally, in some embodiments of the present application, the animal manure includes, but is not limited to, one or more of chicken manure, cattle manure, sheep manure, and duck manure. The yellow straw includes, but is not limited to, one or more of rice straw, wheat straw, and corn straw. The commodity fuels include shell fuels including, but not limited to, one or more of rice hulls, peanut hulls, melon seed hulls, fruit shells, pine cone hulls, and wheat bran. The forest wood fuel includes, but is not limited to, one or more of old furniture, waste building forms, brushwood, bark, bamboo chips, bamboo shavings, and shrubs.

The beneficial effect of this application lies in:

the application provides a uniform mixing preparation method of biomass fuel containing animal wastes, which solves the harmless and efficient treatment problem of the wastes of a farm and also solves the stable operation problem of a biomass power plant. The methods mentioned in this application are also referred to as fecal management in other types of farms.

The method can effectively improve the combustion degree of the chicken manure so as to meet the combustion requirement; the biomass fuel obtained by the method has good combustibility when the mixing amount of the chicken manure is even up to 58%. It can be seen that the biomass fuel of the application is doped with a large amount of chicken manure, so that the overall cost of the biomass fuel can be obviously reduced, namely, the production cost of a power plant can be obviously reduced, and the benefit is improved. Therefore, the method realizes the combustibility of the chicken manure with high mixing amount, reduces the cost and improves the economic benefit.

The preparation method adopting the animal waste, the rice straw and the wheat straw is beneficial to solving the problems of shortage of fuel and environmental protection of the existing biomass direct-fired power plant, and meets the requirements of quantity, quality, cost and environmental protection emission of the fuel of the biomass direct-fired power plant.

In addition, by applying the preparation method of the biomass fuel and the biomass fuel, domestic poultry excrement and rice and wheat straws in a farm can be utilized, and 50% of fuel substitution is realized, so that the benefit of a 30MW biomass direct-combustion power plant can be increased by about more than ten million every year.

Detailed Description

The technical solutions in the embodiments of the present application will be described clearly and completely below, and it should be understood that the described embodiments are only a part of the embodiments of the present application, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The embodiment of the application provides a preparation method of biomass fuel and the biomass fuel. The following are detailed below. It should be noted that the following description of the embodiments is not intended to limit the preferred order of the embodiments. In addition, in the description of the present application, the term "including" means "including but not limited to". Various embodiments of the present application may exist in a range of versions; it is to be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the application; accordingly, the description of a range should be considered to have specifically disclosed all the possible sub-ranges as well as individual numerical values within that range. For example, it is contemplated that the description of a range from 1 to 6 has specifically disclosed sub-ranges such as, for example, from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as individual numbers within a range such as, for example, 1, 2, 3, 4, 5, and 6, as applicable regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any number (fractional or integer) recited within the indicated range.

Example 1

The embodiment provides a biomass fuel, the fuel and blending mass ratio of which are shown in Table 1,

TABLE 1

As shown in table 1, the mass ratio of animal wastes, yellow straws, small-variety fuels and forest wood fuels in the biomass fuels is 35: 54: 6: 5. the chicken manure fuel is preferably selected as the animal manure, the corn straw and the rice straw are preferably selected as the yellow straw to be used as the field pickup packaging material, and the mass ratio of the corn straw to the rice straw is respectively 27% and 27%. The common rice hulls are preferably selected as the small-grade fuel. The wood raw material is selected from the board broken material with wider selection

The preparation method of the biomass fuel comprises the following steps:

directly mixing the yellow straw bales, and performing segmented shear type crushing, wherein the section of a crushed material is provided with a knife edge in order, the crushing length is not more than 7cm, and the crushed straws have no adhesion or agglomeration. The forest wood fuel is crushed into the size length of no more than 10cm and the thickness and width of no more than 7cm after iron removal.

Laying the treated yellow straws, forest wood fuel, animal waste and small variety fuel layer by layer in sequence according to the mass ratio, wherein the material distribution mode is shown in Table 2: one layer is yellow straw, two layers are small-grade fuel, three layers are animal manure, four layers are forest wood fuel, five layers are yellow straw, six layers are small-grade fuel, seven layers are animal manure (such as chicken manure), eight layers are forest wood fuel, nine layers are yellow straw, ten layers are small-grade fuel, eleven layers are animal manure, and twelve layers are forest wood fuel. The sequence of the small-variety fuel, the animal waste, the forest wood fuel and the yellow straw is only an example of one of the preferable sequences, and the sequencing can be optimized according to various biomass boilers and other actual situations on site during specific implementation.

For the construction of the travelling crane device, during blending, the travelling crane sequentially grabs the fuel of each variety according to the sequence in the table 2, then freely falls from the air, and is overlapped layer by layer according to the proportion to more than three fuel layer combination units, and the specific layer number is mixed more than three times according to the actual dry material shed height. For the non-travelling device, fuel is laid layer by a loader according to the plane sequence of the blending field according to the proportion, the fuel is distributed to more than three fuel layer combination units, the specific layer number is rolled and stirred for more than five times according to the space of the actual blending field. The uniformly mixed fuel is fed into a fuel feeding port in batches and is conveyed to a biomass boiler end by a feeding system.

TABLE 2

Example 2

The embodiment provides a biomass fuel, the fuel and blending mass ratio thereof are shown in Table 3,

TABLE 3

As shown in table 3, the mass ratio of the animal waste, the yellow straw, the small-variety fuel and the forest wood fuel in the biomass fuel is 27: 45: 19: 9.

the chicken manure is preferably selected as the animal manure, the corn straw and the rice straw are preferably selected as the yellow straw to be picked up and packaged in the field, and the mass ratio of the corn straw to the rice straw is respectively 18% and 27%. The small fuel is preferably common rice hulls. The forest wood raw material is preferably pine root slices which are more extensive in northeast China

The preparation method of the biomass fuel comprises the following steps:

Laying the treated yellow straws, animal wastes, small-variety fuels and forest wood fuels layer by layer in a multilayer manner according to the mass ratio, wherein the specific material distribution mode is shown in Table 4: one layer is yellow straw, two layers are small-grade fuel, three layers are forest wood fuel, four layers are animal waste, five layers are yellow straw, six layers are small-grade fuel, seven layers are forest wood fuel, eight layers are animal waste, nine layers are yellow straw, ten layers are small-grade fuel, eleven layers are animal waste and twelve layers are forest wood fuel. Here, the sequence of yellow straw, small-variety fuel, animal waste, and forest wood fuel is only an example of one of the preferred sequences, and the sequence can be optimized according to each biomass boiler and other actual situations on site in specific applications.

For the construction of the traveling crane device, during blending, the traveling crane sequentially grabs the fuel of each variety according to the sequence in the table 4 and then freely falls from the air, and the fuel is sequentially overlapped layer by layer according to the proportion to more than twelve layers, and the specific number of layers is mixed for more than 3 times according to the actual dry material shed height. For the non-travelling device, the loader sequentially lays the fuel layer by layer according to the proportion according to the plane sequence of the blending field, the material is distributed to more than twelve layers, and the paved mixture is rolled and stirred for more than five times according to the actual blending field space. And the uniformly mixed fuel is fed into a fuel feeding port in batches and is conveyed to the biomass boiler end by a feeding system.

TABLE 4

Examples 3 to 12

Examples 3 to 12 each provide a biomass fuel, and the fuel and blending mass ratios thereof are shown in table 5, and table 5

Blending is carried out according to blending formulas of various fuels in the table 5, so that the biomass fuels of the embodiments 3-12 can be obtained. The fuel types were the same as the raw material types in example 1, and the difference was mainly in the blending amount.

The method for producing a biomass fuel according to embodiment 3 to embodiment 12 includes the steps of:

The treated yellow straws, animal wastes, small-variety fuels and forest wood fuels are sequentially distributed in a multilayer and layer-by-layer mode according to the mass ratio, and the specific distribution mode is shown in Table 6: one layer is yellow straw, two layers are small-grade fuel, three layers are animal waste, four layers are forest wood fuel, five layers are yellow straw, six layers are animal waste, seven layers are forest wood fuel, eight layers are small-grade fuel, nine layers are yellow straw, ten layers are small-grade fuel, eleven layers are animal waste, and twelve layers are forest wood fuel. Here, the sequence of yellow straw, small-variety fuel, animal waste, and forest fuel is only an example of one of the preferred sequences, and the specific implementation can be optimized according to each biomass boiler and other actual situations on site.

For the construction of the travelling crane device, during blending, the travelling crane sequentially grabs the fuel of each variety according to the sequence in the table 6, then freely falls from the air, and is overlapped layer by layer according to the proportion until the fuel is overlapped to more than three fuel layer combination units, and the specific layer number is mixed for more than 3 times according to the actual dry material shed height. For the non-travelling device, fuel is laid layer by a loader according to the plane sequence of the blending field according to the proportion, the fuel is distributed to more than three fuel layer combination units, the specific layer number is according to the space of the actual blending field, and the laid mixture is stirred for more than five times. The uniformly mixed fuel is fed into a fuel feeding port in batches and is conveyed to the biomass boiler end by a feeding system.

TABLE 6

Test example 1

The test example performed the tests of the combustion performance of the biomass fuels obtained in examples 1 to 12, such as the parameters of flue gas temperature, bed temperature, flue gas oxygen content, fly ash combustible, slag combustible, boiler efficiency, and the like. The mixed fuel obtained in the embodiment 1-12 is used for burning according to the normal production operation of a power plant, and the actual production data is shown in a table 7.

TABLE 7

Actual production run data in Table 7 show that the formulation and blending schemes according to examples 1-12 can meet the requirements for stable operation of a 1X 30MW high-temperature ultrahigh-pressure circulating fluidized bed unit.

In conclusion, the biomass fuel mixed with the animal wastes obtained by the application can be suitable for the biomass circulating fluidized bed boiler, and can be fully utilized in the circulating fluidized bed boiler through reasonable control and blending of the biomass fuel. Specifically, for example, the calorific value and ash melting point of chicken manure fuel are significantly different from other biomass fuels, but after being blended uniformly by the method of the present application, the calorific value and ash melting point of the blend are uniform. It can be seen that under the condition that this application has animal manure (like chicken manure) in mixture, biomass fuel can the stable combustion, and the operation cost of biomass power plant, the fuel supply of stable biomass power plant can be practiced thrift to the animal manure that burns in mixture, can also solve the high-efficient innocent treatment's of plant excrement and urine problem, makes economic benefits and social maximize. The method of the present application is particularly applicable to biomass direct-fired power plants fueled by biomass materials.

The above embodiments are provided to explain the principles and embodiments of the present application by applying specific examples, and the description of the above embodiments is only used to help understanding the method and the core concept of the present application; meanwhile, for those skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and as described above, the content of the present specification should not be construed as a limitation to the present application.

Claims

1. A preparation method of biomass fuel is characterized by comprising the steps of blending animal waste, yellow straws, small-variety fuel and forest wood fuel in proportion to obtain the biomass fuel;

wherein in the biomass fuel, the blending amount of the animal wastes is 15-58 wt%, the blending amount of the yellow straws is 10-58 wt%, the blending amount of the small-variety fuel is 4-32 wt%, and the blending amount of the forest wood fuel is 0-10 wt%; the biomass fuel is used as the fuel of a biomass circulating fluidized bed boiler.

2. The method for preparing the biomass fuel according to claim 1, wherein the method comprises the steps of:

carrying out segmented shear type crushing on the yellow straws to obtain yellow straw crushed materials with the length less than or equal to 7 cm;

crushing the forest wood fuel after deironing to obtain a forest wood fuel crushed material with the length less than or equal to 10cm and the thickness and width less than or equal to 7 cm;

and paving the yellow straw crushed material, the animal manure, the small variety fuel and the forest wood fuel crushed material layer by layer according to the mixing amount, and mixing to obtain the biomass fuel.

3. The method for preparing the biomass fuel according to claim 2, wherein in the layer-by-layer laying process, a layer of yellow straw broken materials, a layer of animal wastes, a layer of small-variety fuels and a layer of forest wood fuel broken materials form a fuel layer combination unit, and more than three fuel layer combination units are laid.

4. The method for preparing the biomass fuel according to any one of claims 1 to 3, wherein the blending amount of the animal waste is 25 to 50 wt%, the blending amount of the yellow straw is 20 to 45 wt%, the blending amount of the small-variety fuel is 12 to 28 wt%, and the blending amount of the forest wood fuel is 2 to 6 wt%.

5. The method for preparing the biomass fuel according to any one of claims 1 to 3, wherein the animal manure comprises one or more of chicken manure, cow manure, sheep manure and duck manure; and/or

The yellow straw comprises one or more of rice straw, wheat straw and corn straw.

6. The method for producing the biomass fuel according to any one of claims 1 to 3, wherein the small-variety fuel includes a shell fuel.

7. The method of claim 6, wherein the shell-based fuel comprises one or more of rice hulls, peanut shells, melon seed shells, fruit shells, pine cone hulls, and wheat bran.

8. The preparation method of the biomass fuel according to any one of claims 1 to 3, wherein the forest wood fuel comprises one or more of old furniture, waste building templates, brushwood, bark, bamboo chips, root chips and bamboo cuttings.

9. The biomass fuel prepared by the method for preparing the biomass fuel according to any one of claims 1 to 8, characterized by comprising: the blending amount of the animal manure is 15-58 wt%, the blending amount of the yellow straw is 10-58 wt%, the blending amount of the small-variety fuel is 4-32 wt%, and the blending amount of the forest fuel is 0-10 wt%.

10. The biomass fuel of claim 9, wherein the animal manure comprises one or more of chicken manure, cattle manure, sheep manure, and duck manure; and/or

The yellow straw comprises one or more of rice straw, wheat straw and corn straw. The small variety fuel comprises shell fuel, and the shell fuel comprises one or more of rice hull, peanut shell, melon seed shell, fruit shell, pinecone shell and wheat bran; and/or

The forest wood fuel comprises one or more of old furniture, waste building templates, brush wood, root pieces, barks, bamboo chips, bamboo sawdust and shrubs.