Resourceful treatment method for preparing derived fuel from kitchen waste

Abstract

The invention relates to the technical field of derived fuel preparation, and discloses a resourceful treatment method for preparing derived fuel from kitchen waste, which comprises the following steps: sorting the waste: sorting the waste into dry components and wet components; crushing and sorting: respectively crushing the wet components and the dry components, crushing the wet components, feeding the crushed wet components into a microbiological treatment system, and performing high-temperature aerobic fermentation to obtain decomposed materials; coarsely crushing the dry components until the particle size is less than or equal to 100mm for later use The particle size of particles obtained after fine crushing is smaller than or equal to 20 mm; mixing additives: mixing the finely crushed dry components, the decomposed materials and the additives in proportion; granulating: granulating to obtain the briquette fuel; and low-temperature drying: transporting the briquette fuel into a low-temperature drying machine, and drying to obtain the derived fuel. According to the invention, the reduction and recycling of the kitchen waste are realized, the carbon emission is reduced, the realization of a dual-carbon target is facilitated, and a new solution can be provided for the resource utilization of the kitchen waste.

Description

Technical Field

[0001] The invention relates to the technical field of derivative fuel preparation, and in particular to a resource processing method for preparing derivative fuel by utilizing kitchen waste. Background Art

[0002] With the acceleration of my country's modernization process, people's living standards are improving. The increase in consumption levels has led to the rapid growth of the catering industry, and the amount of food waste has also increased sharply. Especially in economically developed cities or areas with a high quality of life, there is still a huge gap in my country's ability to dispose of food waste resources.

[0003] my country's food waste has the characteristics of high water content, high oil and high salt. The random stacking of food waste is prone to fermentation, corruption, sourness and stink, and breeding bacteria and flies, which in turn causes water pollution and poses a food safety hazard. If leakage occurs during the collection and transportation process, it will also pollute the air, soil and water sources, seriously endangering people's normal lives.

[0004] Refuse-derived fuel (RDF) can be used as an effective way to reduce, detoxify and recycle waste. RDF not only has a good energy substitution effect, but also reduces carbon dioxide emissions. It is a green, environmentally friendly, high-quality and low-cost alternative fuel. RDF waste-derived fuel will be in great demand in the cement industry and coal-fired boiler industry in the future, and has great prospects.

[0005] However, due to the complex and variable composition of food waste, the composition of waste varies greatly in different regions and at different times, resulting in instability of key indicators such as the calorific value and moisture content of the raw materials, which in turn causes the problem of unsatisfactory calorific value of derived fuels. Therefore, it is urgent to develop a new food waste resource composting technology that can improve and ensure the calorific value of derived fuels. Summary of the invention

[0006] The present invention aims to provide a resource processing method for preparing derived fuels using food waste, so as to solve the problem of unsatisfactory calorific value of derived fuels in the prior art.

[0007] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a derivative fuel prepared from food waste, characterized in that: calculated by weight, it includes the following raw materials: 10 to 30 parts of decomposed materials, 60 to 85 parts of domestic waste, and 1 to 10 parts of additives, wherein the additives include a dechlorinator and a combustion aid, and the addition ratio of the dechlorinator to the combustion aid is 1.5 to 4.

[0008] Preferably, as an improvement, the dechlorination agent is at least one of calcium oxide, fly ash, steel slag, marble saw, and sintered red mud.

[0009] Preferably, as an improvement, the combustion aid is at least one of slag, coal gangue, aluminum slag and red mud.

[0010] Preferably, as an improvement, a method for resource processing of preparing derived fuel using kitchen waste is characterized by comprising the following steps:

[0011] Step 1: Garbage sorting: divided into dry components and wet components;

[0012] Step 2: Crushing and sorting: crush the wet components and dry components separately, and the wet components are crushed and then enter the microbial treatment system to obtain mature materials after high-temperature aerobic fermentation; the dry components are roughly crushed to a particle size of ≤100mm for standby use;

[0013] Step 3: Fine crushing: The dry components after coarse crushing are sent to the fine crusher, and the particle size after fine crushing is ≤20mm;

[0014] Step 4: Mixing additives: Mix the finely crushed dry components, decomposed materials and additives in proportion;

[0015] Step 5: Granulation: The mixed materials are transported to a granulator via a belt to obtain granulated fuel;

[0016] Step 6: Low-temperature drying: transport the molded fuel to a low-temperature dryer and obtain the derived fuel after drying.

[0017] Preferably, as an improvement, in step one, the dry component is domestic waste, including combustibles; and the wet component is food waste.

[0018] Preferably, as an improvement, in step 2, the matured material is obtained by subjecting the wet components to high-temperature aerobic fermentation.

[0019] Preferably, as an improvement, the biological agents used in the high-temperature aerobic fermentation include Brevibacterium epiderm idis, Penicillium digitatum, Bacillus subtilis, protease, amylase, cellulase, bagasse, walnut shell, grapefruit peel, orange peel and sawdust, and the total addition amount of the bacterial species in the biological agent is 2-3%; the process parameters of the aerobic fermentation are: initial moisture content ≤ 70%, initial temperature 0-45°C, maximum temperature 55-80°C during fermentation, then maintaining the medium temperature in the range of 30-50°C for decomposition, C / N of the raw material is 20-35, pH is 6.5-7.5, oxygen concentration is 14-17%, fermentation time is 2-7d, and the moisture content of the mature material after fermentation and degradation is <30%.

[0020] Preferably, as an improvement, in step 2, the coarsely crushed dry components are sieved through a sieve and those with a particle size greater than 100 mm are coarsely crushed again until the crushed particle size reaches the standard and enters the next process.

[0021] Preferably, as an improvement, in step five, the molding pressure is 5 to 30 MPa, the molding temperature is 80 to 100° C., and the moisture content after molding is 10% to 30%.

[0022] Preferably, as an improvement, in step six, the drying temperature is 30-45° C., and the drying time is 30-60 min.

[0023] The principle and advantages of this scheme are: in actual application, in this technical scheme, in view of the technical problems existing in the process of preparing derived fuels using domestic garbage and kitchen waste in the prior art, the inventor has made an overall and comprehensive optimization of the raw materials and preparation process of the derived fuels: using domestic garbage and kitchen waste as raw materials, the kitchen waste can be treated by microorganisms to aerobic degrade kitchen waste with a salt content greater than 1%, remove the odor and reduce the moisture content, and then transform it into a decomposed material rich in carbon, nitrogen and other elements, and then these decomposed materials are scientifically proportioned to prepare garbage derived fuel (RDF). In the aerobic fermentation process, there is also an anaerobic environment, which causes a large amount of carbon and nitrogen loss. Corresponding measures are taken to alleviate greenhouse gas emissions and increase the calorific value of the decomposed material after microbial aerobic degradation of kitchen waste. In the high-temperature aerobic fermentation stage, by optimizing the fermentation conditions: the fermentation time is controlled to be about 2 to 7 days, the initial moisture content is controlled to be below 70%, and the pH is between 6.5 and 7.5; the appropriate oxygen concentration is 14% to 17%, and the moisture content of the finally formed derived fuel is less than 30%, and the calorific value is ≥6MJ / kg. This technical solution achieves the reduction and resource utilization of restaurant kitchen waste, reduces carbon emissions, helps achieve the "dual carbon" goal, and can provide a new solution for the resource utilization of restaurant kitchen waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a flow chart of a resource processing method for preparing derived fuels using food waste in an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The following is further described in detail through specific implementations, but the implementation of the present invention is not limited thereto. Unless otherwise specified, the technical means used in the following implementations are conventional means well known to those skilled in the art; the experimental methods used are all conventional methods; the materials, reagents, etc. used can all be obtained from commercial channels.

[0026] Program Overview:

[0027] A derived fuel prepared from kitchen waste, wherein the raw materials of the derived fuel are mixed in the following proportions by weight: 10 to 30 parts of decomposed materials, 60 to 85 parts of domestic waste, and 1 to 10 parts of additives.

[0028] The additives include a dechlorinating agent and a combustion aid, and the mixing ratio of the dechlorinating agent to the combustion aid is 1.5 to 4;

[0029] The dechlorinating agent is at least one of calcium oxide, fly ash, steel slag, marble saw, and sintered red mud;

[0030] The combustion aid is at least one of slag, coal gangue, aluminum slag and red mud. Coal gangue and aluminum slag contain oxides such as Al2O3, and slag and red mud contain oxides such as CaO and FeO. They can all act as catalysts and play an important role in the oxygen transfer process.

[0031] like Figure 1 As shown, a method for resource processing of preparing derived fuel using kitchen waste includes the following steps:

[0032] Step 1: Manual sorting: The garbage is divided into dry components and wet components. The dry component is domestic garbage, including combustibles (waste paper, waste plastic, waste textiles, waste wood chips); the wet component is kitchen waste.

[0033] Step 2, crushing and sorting: crush the wet components and dry components separately, and the wet components enter the crushed microbial treatment system to obtain mature material after high-temperature aerobic fermentation; in this embodiment, the biochemical treatment system is used to perform high-temperature aerobic fermentation on the wet components to obtain mature material. The biological agents used in the high temperature aerobic fermentation include Brevibacterium epiderm idis, Penicillium digitatum, Bacillus subtilis, protease, amylase, cellulase, bagasse, walnut shell, grapefruit peel, orange peel and sawdust, and the total amount of bacteria added in the biological agent is 2-3%; the process parameters of aerobic fermentation are: initial moisture content ≤ 70%, initial temperature 0-45°C, medium temperature during fermentation 30-50°C, C / N of raw materials 20-35, pH 6.5-7.5, oxygen concentration 14-17%, fermentation time 2-7 days, and moisture content of the mature material after fermentation degradation <30%. The waste gas generated in the high temperature aerobic fermentation stage is sprayed and dissolved, deodorized and purified (activated carbon adsorption deodorization) before being discharged.

[0034] The dry components are coarsely crushed to a particle size of ≤100mm for later use. The coarsely crushed dry components with a particle size of >100mm are sieved through a sieve and coarsely crushed again until the crushed particle size meets the standard and enters the next process.

[0035] Step 3: Fine crushing: The dry components after coarse crushing are sent to the fine crusher, and the particle size after fine crushing is ≤20mm.

[0036] Step 4: Mixing additives: Feed the finely crushed dry components (domestic waste), decomposed materials and additives into a mixer in proportion and mix them thoroughly.

[0037] Step 5: Forming: The mixed materials are transported to a granulator via a belt for granulation to obtain a shaped fuel. The forming pressure is 5-30 MPa, the forming temperature is 80-100°C, and the moisture content after forming is 10%-30%.

[0038] Step 6. Low-temperature drying: transport the molded fuel to a low-temperature dryer at a drying temperature of 30-45°C for 30-60 minutes to complete the derivative fuel preparation process.

[0039] Example 1

[0040] In this embodiment, a method for resource processing of preparing derived fuel using kitchen waste is basically the same as the general description of the above scheme. The calorific value of the decomposed material obtained by aerobic degradation is about 7.3MJ / kg, and the moisture content is controlled at 30%. In step 4, the mass ratio of dry components (domestic waste), decomposed material, and additives is 0.8:0.15:0.05, wherein the additive is a mixture of calcium oxide, coal gangue, etc. by mass ratio. The derived fuel obtained by mixing, fine crushing, extrusion molding, and processing into garbage derivative fuel (RDF) is measured to have a calorific value of 10.6MJ / kg.

[0041] Example 2

[0042] The difference between this embodiment and embodiment 1 is that: in this embodiment, in step 4, the mass ratio of dry components (domestic waste), decomposed materials and additives is 0.75:0.2:0.05, wherein the additive is a mixture of calcium oxide, coal gangue and other mass ratios, which are mixed, finely crushed, extruded and processed into garbage derivative fuel (RDF). The calorific value of the derived fuel obtained by measurement is 10.3MJ / kg.

[0043] Example 3

[0044] The difference between this embodiment and embodiment 1 is that in this embodiment, in step 4, the mass ratio of dry components (domestic waste), decomposed materials and additives is 0.7:0.25:0.05, wherein the additive is a mixture of calcium oxide and coal gangue in equal mass ratios. The derived fuel obtained by mixing, fine crushing, extrusion molding and processing into waste derivative fuel (RDF) is measured to have a calorific value of 10.1MJ / kg.

[0045] Example 4

[0046] The difference between this embodiment and embodiment 1 is that in this embodiment, in step 4, the mass ratio of dry components (domestic waste), decomposed materials, and additives is 0.65:0.3:0.05, wherein the additive is a mixture of calcium oxide and coal gangue in equal mass ratios. The derived fuel obtained by mixing, fine crushing, extrusion molding, and processing into waste derivative fuel (RDF) is measured to have a calorific value of 9.8MJ / kg.

[0047] Example 5

[0048] The difference between this embodiment and embodiment 1 is that in this embodiment, in step 4, the mass ratio of dry components (domestic waste), decomposed materials and additives is 0.6:0.3:0.1, wherein the additive is a mixture of calcium oxide, red mud, etc. by mass ratio. The derived fuel obtained by mixing, fine crushing, extrusion molding and processing into waste derivative fuel (RDF) is measured to have a calorific value of 9.3MJ / kg.

[0049] Comparative Example 1

[0050] The difference between this comparative example and Example 1 is that in this comparative example, the ratio of dry components (domestic waste) to mature materials is reduced from 0.8:0.15 to 0.6:0.3, and the dry components (domestic waste) in RDF increase. Since the calorific value of dry components (domestic waste) is higher than that of mature materials, when the ratio of dry components (domestic waste) to mature materials decreases, the calorific value of RDF decreases accordingly.

[0051] Comparative Example 2

[0052] The difference between this comparative example and Example 1 is that in this comparative example, the ratio of dry components (domestic waste) to mature materials is reduced from 0.75:0.2 to 0.6:0.3, and the dry components (domestic waste) in RDF increase. Since the calorific value of dry components (domestic waste) is higher than that of mature materials, when the ratio of dry components (domestic waste) to mature materials decreases, the calorific value of RDF decreases accordingly.

[0053] Experimental Example 1 Analysis of main raw material elements

[0054] The RDF was subjected to elemental analysis. The elemental analysis was performed according to the national standard GB476-91, and the C, H, N, and S elements in the sample were analyzed using an automatic elemental analyzer. The O element content was obtained by subtracting C, H, N, S, moisture, and ash content from 100 using the difference method to obtain the O element content on an air-dried basis. The elemental analysis results of the domestic waste-derived fuel raw materials of Example 1 are shown in Table 1.

[0055] Table 1 Elemental analysis of domestic waste derived fuel raw materials

[0056] Carbon C Hydrogen Oxygen Nitrogen Sulfur RDF 44.77 5.28 44.06 0.05 0.03

[0057] Industrial analysis refers to GB / T 212-2008, and the moisture, ash, volatile matter and fixed carbon content of the sample are analyzed. Among them, the method for determining moisture is: weigh 1g of the sample to be tested, place it in a drying oven at 105℃, stay for 2 hours, dry it to constant mass, and then calculate the mass fraction of moisture based on the mass loss. When measuring ash, spread 1g of sample flat into an ash dish and place it in a muffle furnace, then heat the sample to 815℃ at a rate of 15℃ / min in an air atmosphere and stay for 1 hour, remove the ash sample and measure the residual amount in the ash dish. When measuring volatile matter, weigh 1g of sample and place it in a porcelain crucible with a lid, heat it in a muffle furnace at 900℃ for 7min without air, and subtract the moisture mass fraction from the reduced mass fraction. The fixed carbon content is obtained by subtracting the corresponding mass fractions of ash, moisture and volatile matter from 100 by difference subtraction. The analysis results of the raw materials for domestic waste-derived fuel in Example 1 are shown in Table 2.

[0058] Table 2 Industrial analysis of experimental raw materials

[0059] Dry basis % Ash Volatile Matter Fixed Carbon Calorific value (MJ / kg) Household waste 1.60 4.21 83.20 10.99 15.71 Compost 0.96 62.83 31.56 4.65 7.3

[0060] Experimental Example 2 Mechanical Properties and Combustibility Test of Derived Fuel The mechanical properties and combustion performance tests were carried out on the fuels prepared in the above embodiments, and the drop strength, ignition performance and low calorific value were tested. The drop strength reference method was MT / T2004 and the ball drop test method was used for determination; the ignition temperature was measured by Shimadzu differential thermal-thermogravimetric analysis device (model) in Japan. The RDF was ground and powdered, and 3-5 mg of the sample was taken and placed in an Al2O3 crucible. The heating rate was 10K / min, the final temperature was 1073K, and the air flow rate was 30ml / min. The low calorific value was measured by reference to the test method of GB / T212-2008 "Industrial Analysis Method of Coal", and the test results are shown in Table 3.

[0061] Table 3 Mechanical properties and combustion performance test of derivative fuels

[0062]

[0063] As shown in Table 3, the calorific value of the decomposed material obtained by aerobic degradation is about 7.3MJ / kg, and the moisture content is controlled at 30%. Five groups of different ratios were set up, and the ratios of dry components (domestic waste) to decomposed material were 0.8:0.15, 0.75:0.2, 0.7:0.25, 0.65:0.3, and 0.6:0.3, respectively, and a mixture of calcium oxide, coal gangue, etc. in corresponding proportions was added as an additive. The calorific values ​​of the derived fuels obtained were measured to be 10.8MJ / kg, 10.3MJ / kg, 10.1MJ / kg, 9.8MJ / kg, and 9.3MJ / kg, respectively, and the calorific value increased with the increase of the proportion of domestic waste.

[0064] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions and / or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A derived fuel prepared from food waste, characterized in that: The raw materials include 10 to 30 parts of decomposed materials, 60 to 85 parts of domestic garbage and 1 to 10 parts of additives by weight. The additives include dechlorinators and combustion aids. The addition ratio of the dechlorinators to the combustion aids is 1.5 to 4.

2. The derived fuel prepared from food waste according to claim 1, characterized in that: The dechlorinating agent is at least one of calcium oxide, fly ash, steel slag, marble saw and sintered red mud.

3. The derived fuel prepared from food waste according to claim 2, characterized in that: The combustion aid is at least one of slag, coal gangue, aluminum slag and red mud.

4. A method for resource processing of preparing derived fuels from food waste, characterized in that: The steps include: Step 1: Garbage sorting: divided into dry components and wet components; Step 2: Crushing and sorting: crush the wet components and dry components separately, and the wet components are crushed and then enter the microbial treatment system to obtain mature materials after high-temperature aerobic fermentation; the dry components are roughly crushed to a particle size of ≤100mm for standby use; Step 3: Fine crushing: The dry components after coarse crushing are sent to the fine crusher, and the particle size after fine crushing is ≤20mm; Step 4: Mixing additives: Mix the finely crushed dry components, decomposed materials and additives in proportion; Step 5: Granulation: The mixed materials are transported to a granulator via a belt to obtain granulated fuel; Step 6: Low-temperature drying: transport the molded fuel to a low-temperature dryer and obtain the derived fuel after drying.

5. The method for resource processing of preparing derived fuel from food waste according to claim 4, characterized in that: In step one, the dry component is domestic waste, including combustibles; and the wet component is food waste.

6. The method for resource processing of preparing derived fuel from food waste according to claim 5, characterized in that: In step 2, the matured material is obtained by subjecting the wet components to high-temperature aerobic fermentation.

7. The method for resource processing of preparing derived fuel from food waste according to claim 6, characterized in that: The biological agents used in the high-temperature aerobic fermentation include Brevibacterium epiderm idis, Penicillium digitatum, Bacillus subtilis, protease, amylase, cellulase, bagasse, walnut shell, grapefruit peel, orange peel and sawdust, and the total addition amount of the bacterial species in the biological agent is 2-3%; the process parameters of the aerobic fermentation are: initial moisture content ≤ 70%, initial temperature 0-45°C, maximum temperature 55-80°C during fermentation, then the medium temperature is maintained at 30-50°C for decomposition, C / N of the raw material is 20-35, pH is 6.5-7.5, oxygen concentration is 14-17%, fermentation time is 2-7d, and the moisture content of the mature material after fermentation and degradation is less than 30%.

8. The method for resource processing of preparing derived fuel from food waste according to claim 7, characterized in that: In step 2, the coarsely crushed dry components are sieved through a sieve and the particles with a size greater than 100 mm are coarsely crushed again until the crushed particle size reaches the standard and enters the next process.

9. The method for resource processing of preparing derived fuel from food waste according to claim 8, characterized in that: In step five, the molding pressure is 5-30 MPa, the molding temperature is 80-100° C., and the moisture content after molding is 10%-30%.

10. The method for resource processing of preparing derived fuel from food waste according to claim 9, characterized in that: In step six, the drying temperature is 30-45° C., and the drying time is 30-60 min.

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