Pig manure biomass pellet fuel and preparation method thereof

Abstract

The invention relates to pig manure biomass granular fuel and a preparation method thereof, belongs to the technical field of biomass fuel and environmental protection, and particularly relates to a comprehensive treatment and resource utilization technology of livestock and poultry breeding manure. Carrying out solid-liquid separation on the pig farm fresh pig manure through a spiral dry-wet separator to obtain pig manure residues; the method comprises the following steps: drying pig manure residues to reduce the water content to 22-30wt%, then crushing and screening, burdening the pig manure residues, the pretreated sawdust and chicken manure biochar, and further mechanically stirring and mixing for 10-15 minutes to obtain a uniform mixture with the water content of 22-28wt%; carrying out extrusion forming on the obtained mixture by adopting a biomass granulator to obtain the pig manure biomass granular fuel; and naturally cooling the formed pig manure biomass pellet fuel to room temperature, and screening out unqualified products with the length of less than 4mm to obtain oversize products which are qualified pig manure biomass pellet fuel finished products. The method not only solves the problem of ecological environment pollution caused by the pig manure, but also provides thinking and direction for reduction, harmlessness and resource comprehensive utilization of the livestock and poultry manure.

Description

Technical Field

[0001] The invention relates to a pig manure biomass pellet fuel and a preparation method thereof, belonging to the field of biomass fuel technology and environmental protection technology, in particular to the comprehensive treatment and resource utilization technology of livestock and poultry excrement. Background Art

[0002] With the rapid development of my country's animal husbandry, especially large-scale and intensive breeding, the discharge of livestock and poultry manure has continued to increase and concentrate, and the ecological and environmental problems it has brought have become increasingly prominent, seriously affecting the breeding farms and the surrounding environment. Livestock and poultry manure has become the main source of agricultural non-point source pollution. The large amount of surplus livestock and poultry manure far exceeds the soil's absorption capacity, resulting in a sharp increase in resource waste and environmental pollution risks. The efficient management and resource utilization of livestock and poultry manure has become a key technical bottleneck restricting the sustainable development of the breeding industry.

[0003] Existing technologies for treating livestock and poultry manure include direct return to the field as fertilizer, aerobic fermentation to produce organic fertilizer, anaerobic fermentation to produce biogas as gaseous fuel, etc. Direct return of manure to the field is gradually being eliminated due to the risk of secondary pollution that affects the ecological environment; composting and fermentation to produce organic fertilizer has a long fermentation cycle, occupies a large area, and has a harsh operating environment; using fermentation tanks to produce organic fertilizer requires large equipment investment, high operating costs, and limited processing capacity; and anaerobic fermentation to produce biogas is a long process, with expensive equipment costs, low energy utilization, strict operating conditions, and the need for further processing of biogas slurry and biogas residue. In this case, how to comprehensively promote the treatment and resource utilization of livestock and poultry breeding waste has become an urgent problem to be solved in the livestock and poultry breeding industry.

[0004] Biomass fuels are widely available, renewable, and have extremely low greenhouse gas emissions throughout their life cycle. The use of biomass energy in the fuel-using industries has gradually strengthened their awareness, and the demand for biomass fuels is increasing. In view of this, in recent years, there have been many technologies for preparing biomass fuels using livestock and poultry manure. For example, the invention patent (CN114479974A) discloses a resource utilization method for preparing biomass pellet fuel using solid waste from pig farming, using an electroosmotic dehydration device for preliminary dehydration for 6-12 hours, and the moisture content of pig manure after further drying is less than 20%. A multi-effect antibacterial binder is added during the molding process to achieve antibacterial and bonding functions. The invention patent with application number 201110431177.3 discloses a biomass fuel prepared from pig manure, the pellet fuel composition includes pig manure, biomass powder, high carbon ash and slaked lime for deodorization, and deformed starch binder, wherein the more expensive high carbon ash is prepared from fly ash by flotation. The invention patent (CN105441155B) discloses a composite biomass fuel of chicken manure, pig manure, yellow-brown soil and Platycladus orientalis and a preparation method thereof. The method uses a large amount of raw materials, and chicken manure and pig manure account for less than half of the total. The mixture of chicken manure and pig manure needs to be piled up at 30-40°C for 20-30 days. The straw fermentation material used is first crushed and then placed in an environment at 30-40°C for baking to a moisture content of 30-50%, and then 1-3% of the weight of the straw is added to the mixture. The mixture is then piled up and fermented for 10-20 days. Due to the high moisture content of the pellet fuel, it needs to be further dried at 50-70°C after extrusion molding. The invention patent with application number 201310324173.4 discloses a method for preparing solid molded fuel using pig manure as raw material. The molded fuel is composed of dried pig manure raw material, biomass and coal, wherein the dried pig manure raw material is added with 2-5% desulfurization, deodorization and mildew prevention agent, and the additive is prepared by mixing a large amount of quicklime with two or three of ferrous sulfate, magnesium carbonate and chitosan fiber to facilitate the use and storage of pig manure molded fuel.

[0005] Based on the above pig manure treatment and utilization technologies, it can be seen that traditional pig manure fertilizer technology is difficult to consume pig manure on a large scale due to its long production cycle and seasonal limitations in fertilization. The use of pig manure to produce biogas energy is not widely used in China. In order to improve the molding effect and deodorize and prevent mildew, the existing pig manure biomass solid molding fuel needs to use corresponding additives or fermentation treatment, which increases production costs or low production efficiency, which is not conducive to large-scale industrial production. Summary of the invention

[0006] In view of the environmental pollution problem of pig manure and the problems and shortcomings in the process of pig manure utilization, the present invention provides a pig manure biomass pellet fuel and a preparation method thereof. The process flow of the present invention is simple, easy to operate, and has high production efficiency. By separating the fresh pig manure from the dry and wet parts and adding homemade chicken manure biochar powder, the obtained pig manure biomass pellet fuel has high mechanical strength, high molding rate, and combustion performance comparable to that of traditional wood biomass pellet fuel, and has the advantages of being moisture-proof, mildew-proof, and odor-free. This method not only solves the problem of ecological environmental pollution caused by pig manure, but also provides ideas and directions for the reduction, harmlessness, and resource-based comprehensive utilization of livestock and poultry manure.

[0007] To achieve the above purpose, the technical solution of the present invention is:

[0008] A pig manure biomass pellet fuel, based on the dry weight of the pig manure biomass pellet fuel, consists of 70wt%-100wt% of pig manure residue, 0wt%-30wt% of sawdust and 0wt%-10wt% of chicken manure biochar, and the total content of sawdust and chicken manure biochar is ≤30wt%.

[0009] The pig manure biomass pellet fuel is cylindrical, with a diameter of 8-10 mm and a length of 10-75 mm.

[0010] A method for preparing pig manure biomass pellet fuel comprises the following steps:

[0011] (1) Fresh pig manure from a pig farm is separated into solid and liquid by a spiral dry-wet separator to obtain pig manure residue;

[0012] (2) drying the pig manure residue to reduce the moisture content to 22-30 wt%, crushing and screening, and then mixing with the pretreated sawdust and chicken manure biochar, and further mechanically stirring and mixing for 10-15 minutes to obtain a uniform mixture with a moisture content of 22-28 wt%;

[0013] (3) extruding the mixture obtained in step (2) using a biomass pellet machine to obtain pig manure biomass pellet fuel;

[0014] (4) The formed pig manure biomass pellet fuel is naturally cooled to room temperature, and unqualified products with a length of less than 4 mm are screened out, and the screened products are qualified pig manure biomass pellet fuel products.

[0015] The moisture content of the fresh pig manure in step (1) is 75-81wt%, and the moisture content of the pig manure residue after solid-liquid separation is below 58wt%.

[0016] The drying temperature of the pig manure residue in step (2) is 105-110° C. The pig manure residue can be used directly after simple crushing, or can be used after further screening. The screening is performed by screening through a 10-mesh stainless steel sieve, preferably through a 20-mesh stainless steel sieve.

[0017] The wood chips in step (2) are wood chips from common trees such as white pine, fir, arborvitae or masson pine, or sawdust produced during the processing of common trees. The wood chips are pre-treated by drying the water content to 22-28 wt% at a temperature of 105-110° C. and then crushing through a 10-mesh stainless steel sieve.

[0018] The chicken manure biochar in step (2) is prepared by forming fresh chicken manure and 30wt-40wt% sawdust first and then pyrolyzing, with a moisture content of ≤2wt%, and pre-treated by mechanically grinding the chicken manure biochar and then passing it through a 20-mesh to 60-mesh stainless steel sieve to obtain chicken manure biochar powder. The chicken manure biochar in the present invention is made by patent number ZL202311020383.4.

[0019] In the step (3), the biomass pellet machine is a ring type or a roller disc type.

[0020] The pig manure biomass pellet fuel obtained by the present invention has a low calorific value (dry basis) of 17.1-18.5 MJ / kg, a moisture content of less than 8wt%, an ash content (dry basis) of 6.6-10.9wt%, a mechanical durability (also known as mechanical strength, received basis) greater than 99%, and a density of 1.25-1.35 g / cm 3 The chlorine content (Cl, dry basis) is 0.04-0.08wt%, the sulfur content (S, dry basis) is 0.3-0.6wt%, and the nitrogen content (N, dry basis) is 1-1.5wt%.

[0021] The relevant indicators of the pig manure biomass pellet fuel in the present invention are obtained by using the above-mentioned corresponding benchmark tests.

[0022] The beneficial effects of the present invention are:

[0023] (1) The fresh pig manure used is obtained by continuous dry-wet separation by a commercial spiral biomass pellet machine. Fresh pig manure does not require fermentation treatment, which greatly improves the efficiency of raw material pretreatment. Fresh pig manure contains a considerable amount of combustible substances, the main components of which are cellulose, hemicellulose and lignin. It also contains fat, protein, starch, etc., and also contains odor substances such as urea, ammonia and hydrogen sulfide dissolved in water. The fresh pig manure in the pig manure collection pool of the pig farm is separated into solid and liquid by a dry-wet separator, and the unstable and moldy fat and protein, odor substances such as urea, ammonia and hydrogen sulfide that are easy to produce odor, and soluble salts in the pig manure are greatly removed. The manure water after dry-wet separation can be used as liquid fertilizer after fermentation in the manure water pool of the pig farm. The pig manure residue after dry-wet separation is in a loose state, the viscosity is greatly reduced, and the moisture content can be reduced from 75-81wt% of fresh pig manure to less than 58wt%. The lower the moisture content, the cleaner the fresh pig manure residue is, and the less energy is consumed for subsequent drying, which is beneficial to product production.

[0024] (2) Adding homemade chicken manure biochar powder to pig manure biomass pellet fuel can achieve deodorization and mildew prevention effects. The chicken manure biochar itself has a certain porosity after pyrolysis. After mechanical grinding and activation, the porosity is further increased. It has the function of activated carbon and can absorb the odorous gas in the pig manure pellet fuel. Secondly, the biochar has stable chemical properties and good hydrophobicity, which can inhibit the moisture absorption and mildew of the pig manure pellet fuel. In addition, the calorific value of homemade chicken manure biochar is higher than that of pig manure and sawdust, which can improve the combustion performance of pig manure pellet fuel. At the same time, due to the particularity of the raw material chicken manure used to prepare biochar, chicken manure biochar contains a certain amount of stone powder (the main component is calcium carbonate) and a part of calcium oxide (quicklime) formed by the decomposition of stone powder during the pyrolysis process, which plays a role in fixing sulfur for pig manure pellet fuel. Calcium oxide plays a certain bonding effect under the action of moisture and temperature during the molding process of pig manure pellet fuel.

[0025] (3) The pig manure biomass pellet fuel is formed efficiently by a biomass pellet machine, and the finished product has low moisture content. No further drying is required, which saves energy. The moisture content of the pig manure mixture is controlled at 22-28wt% before entering the pellet machine. Under the pressure, shear force and friction of the pellet machine roller, the particle size is further reduced, the contact area of ​​the powder is increased, and the sticky substances such as fat, protein, starch remaining in the pig manure residue and the quicklime contained in the chicken manure biochar promote the forming of pig manure pellet fuel in the die hole channel. During the pelletizing process of pig manure pellet fuel, due to frictional heat generation, the temperature of the pellet machine will rise rapidly. While the high-temperature moisture evaporates, it will soften the cellulose and lignin in the pig manure and sawdust, which is conducive to the forming of pig manure pellet fuel. The forming rate of pig manure biomass pellet fuel reaches more than 98%, and the moisture content is less than 8wt%, which meets the use requirements very well.

[0026] (4) The preparation process of the present invention is short, low-cost and high in production efficiency. The obtained pig manure biomass pellet fuel has a smooth surface, a dense texture, an appearance similar to coal, high mechanical strength, environmental protection and no odor, excellent comprehensive combustion performance, and is convenient for storage and transportation. It can effectively achieve the reduction, harmlessness and resource utilization of livestock and poultry manure, and provides a new way and method for the utilization of biomass energy.

[0027] (5) Through the preparation method of the present invention, the present invention can prepare qualified pig manure biomass pellet fuel products using fresh pig manure residue alone without adding sawdust or chicken manure biochar. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a process flow chart of the method for preparing pig manure biomass pellet fuel of the present invention;

[0029] Figure 2 is a SEM image of chicken manure biochar powder added in Example 2 of the present invention;

[0030] Figure 3 It is the finished pig manure biomass pellet fuel product prepared in Example 4 of the present invention. DETAILED DESCRIPTION

[0031] The present invention will be further described below in conjunction with the accompanying drawings and specific implementation methods.

[0032] Example 1

[0033] like Figure 1 As shown, the pig manure biomass pellet fuel, based on the dry weight of the pig manure biomass pellet fuel, is composed of 80wt% pig manure residue, 15wt% sawdust and 5wt% chicken manure biochar.

[0034] The method for preparing pig manure biomass pellet fuel comprises the following steps:

[0035] (1) The moisture content of fresh pig manure in a pig farm is 81wt% and the solid-liquid separation is carried out by a spiral dry-wet separator to obtain pig manure residue with a moisture content of 55wt%;

[0036] (2) drying the pig manure residue at 105° C. to reduce the moisture content to 26.08 wt%, then crushing and sieving through a 10-mesh stainless steel sieve, mixing 7 kg of pig manure residue with 1.29 kg of pretreated sawdust (crushed white pine sawdust, the sawdust was dried at 105° C. to reduce the moisture content to 24.78 wt%, and then sifted through a 10-mesh stainless steel sieve), and 0.33 kg of chicken manure biochar (prepared by patent number ZL202311020383.4, with a moisture content of 2 wt%, and the chicken manure biochar was mechanically ground and sieved through a 60-mesh stainless steel sieve to obtain chicken manure biochar powder), and further mechanically stirred and mixed for 15 min to obtain a uniform mixture with a moisture content of 24.96 wt%;

[0037] (3) using a roller-type biomass pellet machine to extrude the mixture obtained in step (2) to obtain pig manure biomass pellet fuel;

[0038] (4) The formed pig manure biomass pellet fuel is naturally cooled to room temperature, and unqualified products with a length of less than 4 mm are screened out, and the screened products are qualified pig manure biomass pellet fuel products.

[0039] The finished pig manure biomass pellet fuel obtained in this embodiment is cylindrical, with a diameter of 8-9mm and a length of 10-40mm. The pig manure biomass pellet fuel has no odor, has good moisture and mildew resistance, a mechanical durability of 99.3%, and a density of 1.33g / cm 3 The other properties and molding effects of pig manure biomass pellet fuel are shown in Table 1.

[0040] Example 2

[0041] like Figure 1As shown, the pig manure biomass pellet fuel, based on the dry weight of the pig manure biomass pellet fuel, is composed of 80wt% pig manure residue, 10wt% sawdust and 10wt% chicken manure biochar.

[0042] The method for preparing pig manure biomass pellet fuel comprises the following steps:

[0043] (1) The moisture content of fresh pig manure in the pig farm is 79wt% and the solid-liquid separation is carried out by a spiral dry-wet separator to obtain pig manure residue with a moisture content of 58wt%;

[0044] (2) drying the pig manure residue at 105° C. to reduce the moisture content to 30 wt%, then crushing and sieving through a 20-mesh stainless steel sieve, mixing 7 kg of pig manure residue with 0.85 kg of pretreated sawdust (fir sawdust, the sawdust was dried at 105° C. to reduce the moisture content to 28 wt%, and then sifted through a 10-mesh stainless steel sieve), and 0.62 kg of chicken manure biochar (self-made by patent number ZL202311020383.4, with a moisture content of 1.21 wt%, and the chicken manure biochar was mechanically ground and sieved through a 40-mesh stainless steel sieve to obtain chicken manure biochar powder), and further mechanically stirred and mixed for 15 min to obtain a uniform mixture with a moisture content of 27.69 wt%;

[0045] (3) extruding the mixture obtained in step (2) using a ring-type biomass pellet machine to obtain pig manure biomass pellet fuel;

[0046] (4) The formed pig manure biomass pellet fuel is naturally cooled to room temperature, and unqualified products with a length of less than 4 mm are screened out, and the screened products are qualified pig manure biomass pellet fuel products.

[0047] The SEM (scanning electron microscope) morphology of the chicken manure biochar powder added in this example is as follows Figure 2 As shown, it can be clearly seen that the chicken manure biochar has a relatively developed pore structure and good adsorption properties.

[0048] The finished pig manure biomass pellet fuel obtained in this embodiment is cylindrical, with a diameter of 9-10mm and a length of 10-50mm. The pig manure biomass pellet fuel has no odor, has good moisture and mildew resistance, a mechanical durability of 99.1%, and a density of 1.35g / cm 3 The other properties and molding effects of pig manure biomass pellet fuel are shown in Table 1.

[0049] Example 3

[0050] like Figure 1 As shown, the pig manure biomass pellet fuel, based on the dry weight of the pig manure biomass pellet fuel, is composed of 70wt% pig manure residue, 25wt% sawdust and 5wt% chicken manure biochar.

[0051] The method for preparing pig manure biomass pellet fuel comprises the following steps:

[0052] (1) The moisture content of fresh pig manure in a pig farm is 77wt% and the solid-liquid separation is carried out by a spiral dry-wet separator to obtain pig manure residue with a moisture content of 58wt%;

[0053] (2) drying the pig manure residue at 110° C. to reduce the moisture content to 24.76 wt%, and then crushing it for direct use; mixing 7 kg of pig manure residue with 2.47 kg of pretreated sawdust (crushed sawdust of Platycladus orientalis, the sawdust was dried at 105° C. to reduce the moisture content to 23.84 wt%, and then passed through a 10-mesh stainless steel sieve) and 0.38 kg of chicken manure biochar (self-made by patent number ZL202311020383.4, with a moisture content of 1 wt%, and the chicken manure biochar was mechanically ground and passed through a 20-mesh stainless steel sieve to obtain chicken manure biochar powder) and further mechanically stirred and mixed for 15 min to obtain a uniform mixture with a moisture content of 23.61 wt%;

[0054] (3) extruding the mixture obtained in step (2) using a ring-type biomass pellet machine to obtain pig manure biomass pellet fuel;

[0055] (4) The formed pig manure biomass pellet fuel is naturally cooled to room temperature, and unqualified products with a length of less than 4 mm are screened out, and the screened products are qualified pig manure biomass pellet fuel products.

[0056] The finished pig manure biomass pellet fuel obtained in this embodiment is cylindrical, with a diameter of 9-10mm and a length of 20-75mm. The pig manure biomass pellet fuel has no odor, has good moisture and mildew resistance, a mechanical durability of 99.5%, and a density of 1.29g / cm 3 The other properties and molding effects of pig manure biomass pellet fuel are shown in Table 1.

[0057] Example 4

[0058] like Figure 1 As shown, the pig manure biomass pellet fuel, based on the dry weight of the pig manure biomass pellet fuel, is composed of 70wt% pig manure residue and 30wt% sawdust.

[0059] The method for preparing pig manure biomass pellet fuel comprises the following steps:

[0060] (1) Fresh pig manure with a moisture content of 75 wt% in a pig farm is separated into solid and liquid by a spiral dry-wet separator to obtain pig manure residue with a moisture content of 52 wt%;

[0061] (2) drying the pig manure residue at 110° C. to reduce the moisture content to 22 wt %, then crushing and sieving through a 20-mesh stainless steel sieve, mixing 7 kg of the pig manure residue with 3 kg of pretreated sawdust (Masson pine sawdust, which was dried at 110° C. to reduce the moisture content to 22 wt %, and then sieving through a 10-mesh stainless steel sieve), and further mechanically stirring and mixing for 10 min to obtain a uniform mixture with a moisture content of 22 wt %;

[0062] (3) using a roller-type biomass pellet machine to extrude the mixture obtained in step (2) to obtain pig manure biomass pellet fuel;

[0063] (4) The formed pig manure biomass pellet fuel is naturally cooled to room temperature, and unqualified products with a length of less than 4 mm are screened out, and the screened products are qualified pig manure biomass pellet fuel products.

[0064] The pig manure biomass pellet fuel obtained in this embodiment is cylindrical, with a diameter of 9-10mm and a length of 10-60mm. The pig manure biomass pellet fuel has no odor, is moisture-proof and mildew-proof, has a mechanical durability of 99.5%, and a density of 1.25g / cm 3 The other properties and molding effects of the pig manure biomass pellet fuel are shown in Table 1. The finished pig manure biomass pellet fuel prepared in this embodiment is shown in the figure Figure 3 As shown, from Figure 3 It can be seen that the pig manure biomass pellet fuel has a smooth surface, dense texture and high mechanical strength.

[0065] Example 5

[0066] like Figure 1 As shown, the pig manure biomass pellet fuel, based on the dry weight of the pig manure biomass pellet fuel, is composed of 98wt% pig manure residue and 2wt% chicken manure biochar.

[0067] The method for preparing pig manure biomass pellet fuel comprises the following steps:

[0068] (1) Fresh pig manure with a moisture content of 80 wt% in a pig farm is separated into solid and liquid by a spiral dry-wet separator to obtain pig manure residue with a moisture content of 55 wt%;

[0069] (2) drying the pig manure residue at a temperature of 108° C. to reduce the moisture content to 26 wt %, then crushing and sieving through a 20-mesh stainless steel sieve, mixing 7.21 kg of the pig manure residue with 0.11 kg of pretreated chicken manure biochar (prepared by patent number ZL202311020383.4, with a moisture content of 1 wt %, and mechanically grinding the chicken manure biochar and sieving through a 60-mesh stainless steel sieve to obtain chicken manure biochar powder), and further mechanically stirring and mixing for 10 min to obtain a uniform mixture with a moisture content of 25.62 wt %;

[0070] (3) extruding the mixture obtained in step (2) using a ring-type biomass pellet machine to obtain pig manure biomass pellet fuel;

[0071] (4) The formed pig manure biomass pellet fuel is naturally cooled to room temperature, and unqualified products with a length of less than 4 mm are screened out, and the screened products are qualified pig manure biomass pellet fuel products.

[0072] The finished pig manure biomass pellet fuel obtained in this embodiment is cylindrical, with a diameter of 8-9mm and a length of 10-50mm. The pig manure biomass pellet fuel has no odor, has good moisture and mildew resistance, a mechanical durability of 99.3%, and a density of 1.32g / cm 3 The other properties and molding effects of pig manure biomass pellet fuel are shown in Table 1.

[0073] Example 6

[0074] like Figure 1 As shown, the pig manure biomass pellet fuel, based on the dry weight of the pig manure biomass pellet fuel, consists of 100wt% pig manure residue.

[0075] The method for preparing pig manure biomass pellet fuel comprises the following steps:

[0076] (1) Fresh pig manure with a moisture content of 80 wt% in a pig farm is separated into solid and liquid by a spiral dry-wet separator to obtain pig manure residue with a moisture content of 52 wt%;

[0077] (2) drying the pig manure residue at a temperature of 105° C. to reduce the moisture content to 25 wt %, then crushing and sieving through a 20-mesh stainless steel sieve, and further mechanically stirring and mixing 8 kg of the pig manure residue for 10 minutes to obtain a uniform mixture;

[0078] (3) using a roller-type biomass pellet machine to extrude the mixture obtained in step (2) to obtain pig manure biomass pellet fuel;

[0079] (4) The formed pig manure biomass pellet fuel is naturally cooled to room temperature, and unqualified products with a length of less than 4 mm are screened out, and the screened products are qualified pig manure biomass pellet fuel products.

[0080] The finished pig manure biomass pellet fuel obtained in this embodiment is cylindrical, with a diameter of 8-9mm and a length of 10-75mm. The pig manure biomass pellet fuel has basically no odor, is moisture-proof and mildew-proof, has a mechanical durability of 99.1%, and a density of 1.31g / cm 3 The other properties and molding effects of pig manure biomass pellet fuel are shown in Table 1.

[0081] Comparative Example 1

[0082] The pig manure biomass pellet fuel is composed of 80wt% fresh pig manure residue, 15wt% sawdust and 5wt% chicken manure biochar based on the dry weight of the pig manure biomass pellet fuel. Its composition and preparation method are the same as those of Example 1, and the difference from Example 1 is that the moisture content of the uniform mixture after stirring and mixing in step (2) is 16wt%. The prepared pig manure biomass pellet fuel has no odor, is mildew-proof, has a mechanical durability of 78.5%, and a density of 1.16g / cm 3 The other properties and molding effects of pig manure biomass pellet fuel are shown in Table 1.

[0083] Comparative Example 2

[0084] The pig manure biomass pellet fuel, based on the dry weight of the pig manure biomass pellet fuel, is composed of 70wt% fresh pig manure and 30wt% sawdust. Its composition and preparation method are the same as those of Example 4. The only difference from Example 4 is that there is no step (1), that is, the fresh pig manure from the pig farm is not separated into solid and liquid by a spiral dry-wet separator. After sampling, the fresh pig manure from the pig farm is directly dried from the original moisture content of 75wt% to reduce the moisture to 22wt%. The prepared pig manure biomass pellet fuel has a distinct odor, is more susceptible to moisture and deterioration, has a mechanical durability of 95.8%, and a density of 1.35g / cm 3 The other properties and molding effects of pig manure biomass pellet fuel are shown in Table 1.

[0085] Comparative Example 3

[0086] The wood biomass pellet fuel sold on the market is cylindrical in shape, with a diameter of 9-10 mm and a length of 10-50 mm. The cylindrical wood biomass pellet fuel is shown in Table 1, which is the specific properties of the wood biomass pellet fuel in the prior art.

[0087] Table 1 Performance of biomass pellet fuel prepared in Examples 1-6 and Comparative Examples 1-3 of the present invention

[0088]

[0089] The molding rate in Table 1 is the mass fraction of the pig manure biomass pellet fuel obtained after extrusion molding, which is sieved using a stainless steel sieve with a pore size of 4 mm. The mass of the sieve material is divided by the total mass of the pig manure biomass pellet fuel obtained after extrusion molding.

[0090] Combined with the performance of biomass pellet fuel in Table 1 and the mechanical durability and density of pig manure biomass pellet fuel, the pig manure biomass pellet fuel with added chicken manure biochar powder and wood chips has the advantages of no peculiar smell, moisture-proof and mildew-proof, and the pig manure biomass pellet fuel containing chicken manure biochar powder has better performance in this respect. The pure pig manure biomass pellet fuel processed by dry-wet separation is basically odorless and also has the characteristics of moisture-proof and mildew-proof. Comparing comparative example 2 and example 4, the pig manure biomass pellet fuel without dry-wet separation of fresh pig manure has obvious peculiar smell, is more susceptible to moisture and deterioration, and its calorific value (i.e. calorific value), mechanical durability and molding rate have a more obvious reduction, and the ash content is more obviously increased, and the content of elements N, S, and Cl has more than doubled, especially the Cl content, and more energy needs to be consumed in the drying process of pig manure without dry-wet separation, and the drying process is easy to release odorous gases into the air, which seriously affects the surrounding environment. This shows that dry-wet separation and the addition of chicken manure biochar powder have obvious effects on improving the comprehensive performance of pig manure biomass pellet fuel. The pig manure biomass pellet fuel obtained by the invention generates almost no polluting gas (containing S, N or Cl gas) during combustion, and has a relatively good environmental value.

[0091] In addition, when comparing Example 1 and Example 1, although there is no significant change in other properties of the two, the mechanical durability and molding rate of the pig manure biomass pellet fuel prepared from the mixture with a moisture content of 16% are sharply reduced, and are only 78.5% and 58.63% respectively. Further research found that when the moisture content of the mixture is about 12%, the molding rate of the pig manure biomass pellet fuel is less than 1%; when the moisture content of the mixture is about 20%, the molding rate of the pig manure biomass pellet fuel is only about 90%, indicating that the moisture content of the mixture is extremely important to the molding effect of the pig manure biomass pellet fuel.

[0092] It can also be seen from Table 1 that the calorific value of the pig manure biomass pellet fuel obtained by the present invention (the calorific value of Examples 1 to 6) is comparable to or even better than that of the traditional wood biomass fuel (Comparative Example 3), and its ash content, element N, S, and Cl content are determined by the properties of livestock and poultry manure, and the wood chips used in the preparation process can completely use agricultural and forestry waste and related wood left over from wood processing. Therefore, the pig manure biomass pellet fuel obtained by the present invention has a good application prospect in the national economy and life.

[0093] The specific implementation modes of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above implementation modes, and various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention.

Claims

1. A pig manure biomass pellet fuel, characterized by: The pig manure biomass pellet fuel is composed of 70wt%-100wt% pig manure residue, 0wt%-30wt% sawdust and 0wt%-10wt% chicken manure biochar by dry weight, and the total content of sawdust and chicken manure biochar is ≤30wt%.

2. The pig manure biomass pellet fuel according to claim 1, characterized in that: The pig manure biomass pellet fuel is cylindrical, with a diameter of 8-10 mm and a length of 10-75 mm.

3. A method for preparing pig manure biomass pellet fuel according to claim 1 or 2, characterized in that The following steps are involved: (1) Fresh pig manure from a pig farm is separated into solid and liquid by a spiral dry-wet separator to obtain pig manure residue; (2) drying the pig manure residue to reduce the moisture content to 22-30 wt%, crushing and screening, and then mixing with the pretreated sawdust and chicken manure biochar, and further mechanically stirring and mixing for 10-15 minutes to obtain a uniform mixture with a moisture content of 22-28 wt%; (3) extruding the mixture obtained in step (2) using a biomass pellet machine to obtain pig manure biomass pellet fuel; (4) The formed pig manure biomass pellet fuel is naturally cooled to room temperature, and unqualified products with a length of less than 4 mm are screened out, and the screened products are qualified pig manure biomass pellet fuel products.

4. The method for preparing pig manure biomass pellet fuel according to claim 3, characterized in that: The moisture content of the fresh pig manure in step (1) is 75-81wt%, and the moisture content of the pig manure residue after solid-liquid separation is below 58wt%.

5. The method for preparing pig manure biomass pellet fuel according to claim 3, characterized in that: The drying temperature of the pig manure residue in step (2) is 105-110° C. The pig manure residue can be used directly after simple crushing, or can be used after further screening. The screening is performed by screening through a 10-mesh stainless steel sieve, preferably through a 20-mesh stainless steel sieve.

6. The method for preparing pig manure biomass pellet fuel according to claim 3, characterized in that: The wood chips in step (2) are wood chips or sawdust from common trees such as white pine, fir, arborvitae or masson pine, which are pre-treated by drying the moisture content to 22-28 wt% at a temperature of 105-110° C. and then crushing through a 10-mesh stainless steel sieve.

7. The method for preparing pig manure biomass pellet fuel according to claim 3, characterized in that: The chicken manure biochar in step (2) is prepared by forming fresh chicken manure and 30wt%-40wt% sawdust followed by pyrolysis, with a moisture content of ≤2wt%. The pretreatment is to mechanically grind the chicken manure biochar and then sieve it through a 20-mesh-60-mesh stainless steel sieve to obtain chicken manure biochar powder.

8. The method for preparing pig manure biomass pellet fuel according to claim 3, characterized in that: In the step (3), the biomass pellet machine is a ring type or a roller disc type.

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