Biomass fuel containing aquatic product bottom mud residual feed mixture and preparation method thereof

Abstract

The invention belongs to the technical field of biomass fuel preparation, and particularly relates to biomass fuel containing an aquatic product bottom mud residual feed mixture and a preparation method of the biomass fuel. The preparation method comprises the following steps: (1) dehydrating, drying and crushing an aquatic product bottom mud and residual feed mixture to obtain a bottom material raw material; (2) cutting and crushing coconut fibers to obtain coconut fiber powder; and (3) uniformly mixing the substrate raw material with the coconut fiber powder, the anti-coking additive and the oyster shell powder, and granulating the mixture through a granulator to obtain the biomass fuel. Aquaculture substrate waste is adopted as a main raw material, the pressure of tail water treatment in the high-density aquaculture industry is relieved, the culture cost is reduced through recycling of culture bottom mud, a new way is provided for processing of biomass fuel, meanwhile, economic benefits are increased, the process is simple, the application prospect is wide, and the method is suitable for industrial production. And the purposes of energy conservation and environmental protection are achieved while a guarantee is provided for healthy development of the high-density aquaculture industry.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomass fuel preparation, and particularly relates to a biomass fuel containing a mixture of aquatic bottom mud and residual bait and a preparation method thereof. Background Art

[0002] With the continuous growth of energy demand, it is urgent for humans to adjust the energy structure and reduce the dependence on traditional fossil energy. Biomass is an internationally recognized low-carbon, clean and renewable energy. Broadly speaking, biomass fuels include all solid, liquid or gaseous fuels composed of or extracted from biomass. Biomass resources are widely sourced, including agricultural and forestry waste, urban biosolids and waste, water-based or land-based vegetation, and energy crops, etc. They are renewable energy sources with the advantages of energy conservation, environmental protection and high calorific value. To meet the renewable energy target, they can replace gasoline and diesel produced from petroleum to a certain extent. Abroad, biomass energy has been used for heating since a long time ago, and the consumption is significantly greater than the production supply, and the proportion of biomass energy in the use of renewable energy is increasing continuously. The research on biomass fuels in China is also becoming increasingly extensive.

[0003] The invention patent with the publication number of CN106433841A discloses a biomass fuel containing lignin, which is made from the following raw materials: biomass sludge containing straw light ash, straw light ash, lignin, and cellulose mud. By adding plant materials such as straw light ash to the undehydrated sludge, the calorific value of the dehydrated sludge can be increased. The invention patent with the publication number of CN102703155A discloses a biomass fuel based on sludge-straw-coal, its preparation method and the application of fuel slag. The raw coal is mixed with the sludge-straw mixture and then pressed into shape to obtain the biomass fuel.

[0004] Aquaculture, as one of the relatively fast-developing industries in agriculture, plays an important role in ensuring market supply, increasing farmers' income, optimizing the national dietary structure and ensuring food safety. However, with the continuous increase in aquaculture density and feed input, a large amount of bottom substrate mixtures such as residual bait and feces are deposited at the bottom of the pond, which not only brings the pressure of tail water treatment but also causes a series of problems such as aquaculture water body pollution. However, there are few reports on using the mixture of aquatic bottom mud and residual bait as raw materials to prepare biomass fuels and realize the resource utilization of aquaculture by-products. Summary of the Invention

[0005] Aiming at the disadvantages and deficiencies of the above-mentioned existing technologies, the purpose of the present invention is to provide a biomass fuel containing a mixture of aquatic sediment and residual bait and a preparation method thereof. The present invention innovatively uses the by-products of aquaculture bottom sediment as the main raw material for forming biomass fuel. By adjusting and controlling the formula ratio and preparation method, the processing difficulty and production cost of the biomass fuel are reduced, the fuel calorific value of the biomass fuel is increased, and the release of harmful substances is reduced, having broad industrial application prospects. While realizing the resource utilization of aquaculture by-products, it also provides new ideas for the biomass fuel processing field.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A preparation method of a biomass fuel containing a mixture of aquatic sediment and residual bait, comprising the following steps:

[0008] (1) Dehydrating and drying the mixture of aquatic sediment and residual bait, and then pulverizing it to obtain a bottom sediment raw material;

[0009] (2) Cutting and pulverizing coconut coir to obtain coconut coir powder;

[0010] (3) Mixing the bottom sediment raw material evenly with coconut coir powder, an anti-coking additive, and oyster shell powder, and granulating the mixture through a granulator to obtain a biomass fuel.

[0011] Further, the mixture of aquatic sediment and residual bait in step (1) comprises the following components in mass percentage: fish excrement 40 - 60%, bottom sediment 20 - 40%, and residual feed 20 - 30%. The mixture of aquatic sediment and residual bait mainly comes from the bottom of aquaculture ponds. According to the types of fish raised and different feeding feeds, there will be corresponding differences in the bottom sediment content.

[0012] Further, the dehydration in step (1) refers to dehydration using a filter press to make the moisture content of the material below 40%.

[0013] Further, the drying in step (1) refers to drying in a blast drying oven at 40 - 80°C for 12 - 60 h to make the moisture content of the material below 20%.

[0014] Further, the pulverization in steps (1) and (2) refers to pulverizing to 30 - 50 meshes.

[0015] Further, the coconut coir in step (2) is a filamentous substance derived from the coconut shell and is a common natural biomass raw material.

[0016] Further, the anti-coking additive in step (3) is one or a mixture of two of kaolin and metakaolin. Its main mineral component is kaolinite (Al4[Si4O 10(OH)8), with a content of over 90%, is a common natural clay mineral.

[0017] Furthermore, the oyster shell powder mentioned in step (3) is the product of crushed oyster shells, and its calcium carbonate content is 95 - 99%.

[0018] Furthermore, the ratio of each raw material mentioned in step (3) by weight is: 5 - 20 parts of bottom substrate raw material, 70 - 90 parts of coconut coir powder, 4 - 8 parts of anti-coking additive, and 1 - 4 parts of oyster shell powder.

[0019] Furthermore, the diameter of the biomass fuel obtained by granulation in step (3) is 6 - 10 mm, and the length is 20 - 50 mm.

[0020] A biomass fuel is prepared by the above method.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] (1) The raw material composition of the biomass fuel provided by the present invention includes aquaculture bottom substrate by-products, coconut coir, oyster shell powder, and anti-coking additives; the raw materials are simple and easy to obtain, and the aquaculture bottom substrate by-products are recycled, greatly reducing a series of environmental pollutions brought by aquaculture tail water in fisheries, protecting the local environmental ecological functions, and bringing additional economic benefits while reducing treatment costs.

[0023] (2) The present invention only uses natural substances such as oyster shells and kaolin as calcium source additives and anti-coking agent additives. Among them, oyster shells, as a common waste in aquaculture, mainly consist of calcium carbonate. This design uses it as a natural additive in the preparation of biomass fuel. While replacing traditional calcium additives and reducing harmful gas emissions, the method has a simple and easy operation procedure, does not require additional chemical agents, and the preparation process is green and environmentally friendly.

[0024] (3) The biomass fuel obtained by the present invention has good compressibility and high combustion efficiency; it is easy to manufacture, store, and transport. Description of the Drawings

[0025] Figure 1 It is the appearance morphology diagram of the formed biomass fuel obtained in the embodiment of the present invention.

[0026] Figure 2 It is the diagram of different element contents in the biomass fuels obtained in Examples 1 - 3 of the present invention, Control Group 1 (bottom substrate raw material), and Control Group 2 (coconut coir filaments). Detailed Embodiments

[0027] The present invention will be further described in detail below in conjunction with the embodiments and the drawings, but the embodiments of the present invention are not limited thereto.

[0028] Example 1

[0029] A preparation method of a biomass fuel containing an aquaculture bottom mud and residual bait mixture, comprising the following steps:

[0030] (1) Dehydrate the aquaculture bottom mud and residual bait mixture (from the bottom of an aquaculture pond, and its component composition is measured in the following range: fish excrement 40 - 60%, bottom mud 20 - 40%, residual feed 20 - 30%) through a filter press to make its water content reach below 40%, then place it in a blast drying oven and dry it at 60 °C for 48 h, and then put it into a pulverizer to pulverize and collect it through a 40-mesh sieve for standby, obtaining a bottom material raw material with a water content of about 10 wt%.

[0031] (2) Take coconut coir filaments, cut them into small sections and put them into a pulverizer to pulverize. After pulverization, the coconut coir powder is collected through a 40-mesh sieve for standby, obtaining coconut coir powder.

[0032] (3) By mass, mix 15 parts of the bottom material raw material, 79 parts of coconut coir powder, 5 parts of the anti-coking additive kaolin, and 1 part of oyster shell powder (the product after pulverizing oyster shells, and its calcium carbonate content is in the range of 95 - 99%) evenly, and granulate the mixture through a granulator to obtain a biomass fuel with a diameter of 7 mm and a length of 30 - 50 mm. The appearance morphology diagram and element content diagram of the obtained formed biomass fuel are respectively as Figure 1 and Figure 2 shown.

[0033] Example 2

[0034] A preparation method of a biomass fuel containing an aquaculture bottom mud and residual bait mixture, comprising the following steps:

[0035] Steps (1) and (2) are the same as those in Example 1.

[0036] (3) By mass, mix 15 parts of the bottom material raw material, 75 parts of coconut coir powder, 8 parts of the anti-coking additive metakaolin, and 2 parts of oyster shell powder evenly, and granulate the mixture through a granulator to obtain a biomass fuel with a diameter of 8 mm and a length of 30 - 50 mm. The element content diagram of the obtained formed biomass fuel is as Figure 2 shown.

[0037] Example 3

[0038] A preparation method of a biomass fuel containing an aquaculture bottom mud and residual bait mixture, comprising the following steps:

[0039] Steps (1) and (2) are the same as those in Example 1.

[0040] (3) By mass, 8.5 parts of bottom substrate raw material are mixed evenly with 85 parts of coconut coir powder, 5 parts of anti-coking additive (kaolin and metakaolin with a mass ratio of 1:1), and 1.5 parts of oyster shell powder. The mixture is granulated by a granulator to obtain biomass fuel with a diameter of 10 mm and a length of 40 - 50 mm. The elemental content diagram of the obtained formed biomass fuel is as shown in Figure 2 shown.

[0041] Control Group 1

[0042] This control group uses the bottom substrate raw material obtained in Example 1. Its elemental content diagram is as shown in Figure 2 shown.

[0043] Control Group 2

[0044] This control group uses the coconut coir fiber raw material in Example 1. Its elemental content diagram is as shown in Figure 2 shown.

[0045] Control Group 3

[0046] A preparation method of biomass fuel containing aquaculture bottom mud and residual bait mixture. Compared with Example 1, an equal amount of dried and pulverized corn straw biomass is used to replace the coconut coir powder, and the rest is the same.

[0047] The dry basis calorific value and fuel density of the biomass fuel samples obtained from the above Examples 1 - 3 and Control Groups 1 - 3 are measured, and their energy density is calculated. The results are shown in Table 1 below.

[0048] Table 1

[0049] Sample Calorific value on dry basis kcal / kg <![CDATA[Fuel density g / cm 3 > <![CDATA[Energy density kcal / m 3 > Example 1 3678 1.34 4928.52 Example 2 3737 1.25 4671.25 Example 3 3927 1.26 4948.02 Control group 1 693 2.21 1531.53 Control group 2 4307 0.53 2282.71 Control group 3 3256 1.12 3646.72

[0050] Example 4

[0051] A preparation method of biomass fuel containing aquaculture bottom mud and residual bait mixture, comprising the following steps:

[0052] (1) The aquaculture bottom mud and residual bait mixture (the same as in Example 1) is dehydrated by a filter press to make its water content reach below 40%, then placed in a forced air drying oven at 50 °C and dried for 48 h, and then put into a pulverizer to be pulverized and passed through a 30 - mesh sieve for collection and standby, obtaining a bottom substrate raw material with a water content of about 14 wt%.

[0053] (2) Take coconut coir fiber, cut it into small sections and put it into a pulverizer to be pulverized. After pulverization, the coconut coir powder is passed through a 30 - mesh sieve for collection and standby, obtaining coconut coir powder.

[0054] (3) By mass, mix 5 parts of bottom substrate raw material, 90 parts of coconut coir powder, 4 parts of anti-coking additive kaolin, and 1 part of oyster shell powder evenly. Granulate the mixture through a granulator to obtain biomass fuel with a diameter of 6 mm and a length of 20 - 40 mm. The energy density of the biomass fuel obtained in this example is calculated to be 4896.65 kcal / m 3 。

[0055] Example 5

[0056] A preparation method of biomass fuel containing a mixture of aquaculture bottom mud and residual bait includes the following steps:

[0057] (1) Dehydrate the mixture of aquaculture bottom mud and residual bait (same as in Example 1) through a filter press to make its water content reach below 40%, then place it in a forced-air drying oven at 80 °C for 12 h, and then put it into a pulverizer to pulverize and collect it through a 50-mesh sieve for standby, obtaining bottom substrate raw material with a water content of about 8 wt%.

[0058] (2) Take coconut coir filaments, cut them into small sections and put them into a pulverizer to pulverize. After pulverization, collect the coconut coir powder through a 50-mesh sieve for standby, obtaining coconut coir powder.

[0059] (3) By mass, mix 20 parts of bottom substrate raw material, 70 parts of coconut coir powder, 8 parts of anti-coking additive kaolin, and 2 parts of oyster shell powder evenly. Granulate the mixture through a granulator to obtain biomass fuel with a diameter of 9 mm and a length of 40 - 50 mm. The energy density of the biomass fuel obtained in this example is calculated to be 4627.36 kcal / m 3 。

[0060] From the above results, it can be seen that the biomass fuel particles prepared by the present invention are firmly combined, not easy to loosen, and also have the advantages of being easy to manufacture, low cost, and good economic benefits. The dry basis calorific value of the biomass briquette fuel produced by the present invention is 3678 - 3927 kcal / kg, which is higher than the average calorific value of 3585 kcal / kg of biomass fuel made from traditional crop residues (corn straw, rice straw), realizing the efficient resource utilization of aquaculture by-products. At the same time, using coconut coir powder in combination with the bottom substrate raw material results in a significantly increased calorific value and energy density of the biomass briquette fuel compared to other biomasses (such as common corn straw). The biomass briquette fuel prepared by the present invention has a high energy density and a large specific gravity, and can provide 4627.36 - 4948.02 kcal of heat in a unit volume of fuel. At the same time, it greatly improves the disadvantages of low energy utilization rate, large space volume ratio, and difficulty in storage and transportation of aquaculture bottom substrate by-products and coconut coir.

[0061] Control Group 4

[0062] A preparation method of a biomass fuel containing aquaculture bottom mud and residual bait mixture. Compared with Example 1, no anti-coking additive kaolin was added, and the rest was the same.

[0063] Control group 5

[0064] A preparation method of a biomass fuel containing aquaculture bottom mud and residual bait mixture. Compared with Example 1, no oyster shell powder was added, and the rest was the same.

[0065] The dry basis calorific value, slagging rate (determined according to the provisions of NY / T1881.5-2010 "Test Methods for Biomass Solid Formed Fuels - Part 5: Ash") and the fixation rates of S and Cl elements (content of S and Cl elements in the combustion slag / content of S and Cl elements in the biomass fuel * 100%) of the biomass fuel samples obtained from the above Example 1 and Control groups 4 - 5 were tested, and the results are shown in Table 2 below.

[0066] Table 2

[0067] Sample Calorific value on dry basis kcal / kg Slagging rate % Fixation rate of S element % Fixation rate of Cl element % Example 1 3678 10.52 85.6 79.2 Control group 4 2853 12.60 74.9 72.7 Control group 5 3590 9.37 10.5 25.1

[0068] It can be seen from the results in Table 2 that the addition of the anti-coking additive to the biomass formed fuel prepared by the present invention can significantly promote the combustion of the bottom substrate raw materials, improve the calorific value and reduce the slagging rate. At the same time, it also has a certain effect on the fixation of S and Cl elements. The addition of oyster shell powder can significantly enhance the fixation effect of S and Cl elements. It effectively avoids problems such as boiler coking and slagging and high-temperature chlorine corrosion that often occur during the combustion of traditional biomass fuels, and reduces the emission of harmful gases such as SO2. This is attributed to the fact that the added natural oyster shell powder and kaolin act as calcium additives and anti-coking additives respectively. During the high-temperature combustion process, the Ca element in the oyster shell powder and the Al-Si-O-O structural unit in the kaolin fix the S element gasified at high temperature and the alkali metal elements and Cl elements respectively. Therefore, the biomass formed fuel prepared by the present invention is a renewable clean energy that can be widely used in biomass boilers, domestic stoves, and biomass power generation. At the same time, the treatment of aquaculture bottom waste is realized, which not only reduces the pressure of tail water treatment in the high-density aquaculture industry, but also the resource utilization of aquaculture bottom mud reduces the breeding cost and increases the economic benefits, providing a guarantee for the healthy development of the high-density aquaculture industry while achieving the purpose of energy conservation and environmental protection.

[0069] The above embodiments are the preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A preparation method of a biomass fuel containing an aquaculture bottom mud and residual bait mixture, characterized in that, It includes the following steps: (1) Dehydrate and dry the aquaculture bottom mud and residual bait mixture, and then crush it to obtain the bottom substrate raw material; (2) Cut and crush the coconut coir to obtain coconut coir powder; (3) Mix the bottom substrate raw material, coconut coir powder, anti-coking additive and oyster shell powder evenly, and granulate the mixture through a granulator to obtain the biomass fuel.

2. The preparation method of a biomass fuel containing aquatic sediment and residual bait mixture according to claim 1, characterized in that, The aquaculture bottom mud and residual bait mixture described in step (1) includes the following components in mass percentage: fish excrement 40 - 60%, bottom mud 20 - 40%, and residual feed 20 - 30%.

3. The preparation method of a biomass fuel containing an aquaculture bottom mud residual bait mixture according to claim 1, characterized in that, The dehydration described in step (1) refers to dehydrating with a filter press to make the moisture content of the material below 40%.

4. The preparation method of a biomass fuel containing aquatic sediment residual bait mixture according to claim 1, characterized in that, The drying described in step (1) refers to drying in a forced-air drying oven at 40 - 80°C for 12 - 60 h to make the moisture content of the material below 20%.

5. The preparation method of a biomass fuel containing an aquatic sediment residual bait mixture according to claim 1, characterized in that, The crushing described in steps (1) and (2) refers to crushing to 30 - 50 mesh.

6. The preparation method of a biomass fuel containing an aquaculture sediment and residual bait mixture according to claim 1, wherein, The anti-coking additive described in step (3) is one or a mixture of two of kaolin and metakaolin.

7. The preparation method of a biomass fuel containing an aquaculture bottom mud residual bait mixture according to claim 1, characterized in that, The oyster shell powder described in step (3) is the product after crushing oyster shells, and its calcium carbonate content is 95 - 99%.

8. The preparation method of a biomass fuel containing aquatic sediment residual bait mixture according to claim 1, characterized in that, The ratio of each raw material described in step (3) by weight is: 5 - 20 parts of bottom substrate raw material, 70 - 90 parts of coconut coir powder, 4 - 8 parts of anti-coking additive, and 1 - 4 parts of oyster shell powder.

9. The preparation method of a biomass fuel containing an aquaculture bottom mud and residual bait mixture according to claim 1, characterized in that, The diameter of the biomass fuel obtained by granulation in step (3) is 6 - 10 mm, and the length is 20 - 50 mm.

10. A biomass fuel, characterized in that, Prepared by the method according to any one of claims 1 - 9.

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