Method for preparing biochar-based fertilizer through co-pyrolysis of livestock and poultry manure and agricultural and forestry wastes

Abstract

The invention discloses a method for preparing a biochar-based fertilizer through co-pyrolysis of livestock and poultry manure and agricultural and forestry waste, and relates to the technical field of co-pyrolysis preparation of livestock and poultry manure and agricultural and forestry waste. Livestock and poultry manure and agricultural and forestry waste are subjected to solid-liquid separation, a mechanical extrusion, centrifugal separation or filtering method is adopted, and the separated liquid part can be further treated to be used for producing biogas slurry fertilizer; wherein the solid excrement part and the agriculture and forestry waste solid are subjected to crushing treatment together, so that the reaction contact area of the raw materials in the subsequent pyrolysis process is increased; 2, raw material pyrolysis treatment; the method comprises the following steps: uniformly mixing pretreated livestock and poultry manure and agricultural and forestry wastes, and feeding into a pyrolyzing furnace; according to the invention, resource utilization of livestock and poultry manure and agricultural and forestry wastes is realized, substances which are originally discarded and possibly pollute the environment are converted into the biochar-based fertilizer with economic value, the emission of wastes is reduced, the risk of environmental pollution is reduced, and resources are saved at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of co-pyrolysis preparation of livestock and poultry excrement and agricultural and forestry wastes, and more specifically, to a method for preparing biochar-based fertilizer by co-pyrolysis of livestock and poultry excrement and agricultural and forestry wastes. Background Art

[0002] With the rapid development of animal husbandry and agriculture, the generation of livestock manure and agricultural and forestry waste is increasing. Improper handling of livestock manure can lead to environmental and health problems such as eutrophication of water bodies, air pollution, and the spread of pathogens. Traditional incineration of agricultural and forestry waste, such as straw and fallen branches, not only wastes resources but also produces large amounts of greenhouse gases and smoke, seriously polluting the atmospheric environment. Furthermore, livestock manure contains numerous bacteria and viruses, which can easily spread disease. Therefore, the proper disposal and treatment of livestock manure is crucial to reducing environmental pollution. However, the severity of livestock manure pollution has led to water and air pollution. Livestock manure wastewater not only affects environmental quality but also poses a threat to human health.

[0003] One of the effective ways to solve the above problems is to utilize livestock and poultry manure and agricultural and forestry waste as resources to prepare biochar-based fertilizers. Biochar has a rich pore structure, a large specific surface area and good chemical stability. It can improve soil structure, increase soil fertilizer and water retention capacity, promote soil microbial activity, and thus improve soil fertility, creating good conditions for crop growth. However, the current existing methods for preparing biochar-based fertilizers still have deficiencies in raw material processing, pyrolysis process and product performance optimization, resulting in uneven quality of the prepared biochar-based fertilizers, making it difficult to fully utilize the resource value of livestock and poultry manure and agricultural and forestry wastes. Therefore, it is of great significance to develop a method that is efficient, environmentally friendly and can prepare high-performance biochar-based fertilizers. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a method for preparing biochar-based fertilizer by co-pyrolysis of livestock and poultry manure and agricultural and forestry waste.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A method for preparing biochar-based fertilizer by co-pyrolysis of livestock and poultry manure and agricultural and forestry wastes comprises the following steps:

[0007] Step 1: Raw material pretreatment: livestock and poultry manure and agricultural and forestry waste are separated into solid and liquid, and mechanical extrusion, centrifugal separation or filtration are used. The separated liquid part can be further processed for the production of biogas fertilizer; wherein, the solid manure part is crushed together with the agricultural and forestry waste solid to increase the reaction contact area of the raw materials in the subsequent pyrolysis process; Step 2: Raw material pyrolysis treatment: the pretreated livestock and poultry manure and agricultural and forestry waste are mixed evenly and sent to the pyrolysis furnace; pyrolysis is carried out under inert gas or low oxygen environment, wherein the pyrolysis temperature is controlled at 400-700℃ and the pyrolysis time is 1-3h; under these conditions Under the condition of high temperature, the organic components in the raw materials undergo thermal decomposition reaction to generate biochar products; Step three: Raw material reprocessing; The generated biochar is taken out of the pyrolysis furnace and quickly cooled to room temperature by air cooling or water cooling to avoid further oxidation of the biochar at high temperature, and the biochar is mixed with phosphoric acid solution in proportion, and then filtered and washed to neutrality, and then heated for activation treatment; Step four: Addition of nutrients; According to different soil fertility conditions and crop growth needs, add appropriate amounts of nitrogen, phosphorus, potassium and other macro-element fertilizers and calcium, magnesium, zinc, boron and other trace element fertilizers to the activated biochar.

[0008] In the above-mentioned method for preparing biochar-based fertilizer by co-pyrolysis of livestock and poultry manure and agricultural and forestry waste, in step 1, the livestock and poultry manure particles are 1-5 cm in size, and the agricultural and forestry waste is crushed to a length of 2-10 cm.

[0009] The above-mentioned method for producing biochar-based fertilizer by co-pyrolysis of livestock and poultry manure and agricultural and forestry waste involves uniformly mixing pretreated livestock and poultry manure and agricultural and forestry waste in a mass ratio of 1:1-3:1, then feeding the mixture into a pyrolysis furnace for pyrolysis. During the pyrolysis process, the generated pyrolysis gas is purified and collected.

[0010] In the above-mentioned method for preparing biochar-based fertilizer by co-pyrolysis of livestock and poultry manure and agricultural and forestry waste, in step three, the cooled biochar is further crushed by mechanical crushing equipment to a particle size of 0.1-1 mm.

[0011] In the above-mentioned method for preparing biochar-based fertilizer by co-pyrolysis of livestock and poultry manure and agricultural and forestry waste, in step three, biochar is mixed with a phosphoric acid solution with a mass fraction of 10%-30% in a ratio of 1:3-1:5, and stirred and immersed at 80-120°C for 2-4 hours.

[0012] In the above-mentioned method for preparing biochar-based fertilizer by co-pyrolysis of livestock and poultry manure and agricultural and forestry waste, in step three, the temperature of the activation treatment is 500-700° C., and the activation time is 1-2 hours.

[0013] In the above-mentioned method for preparing biochar-based fertilizer by co-pyrolysis of livestock and poultry manure and agricultural and forestry waste, in step four, the biochar-based fertilizer is obtained by respectively putting the activated biochar and trace elements into a stirring device and stirring for 1-2 hours.

[0014] In the above-mentioned method for preparing biochar-based fertilizer by co-pyrolysis of livestock and poultry manure and agricultural and forestry waste, in step 2, the pyrolysis gas generated during the pyrolysis process is purified and collected.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. The present invention realizes the resource utilization of livestock and poultry manure and agricultural and forestry waste, converting the originally discarded materials that may cause environmental pollution into biochar-based fertilizers with economic value, reducing waste emissions, lowering the risk of environmental pollution, and saving resources at the same time.

[0017] 2. In this invention, organic pollutants in livestock and poultry manure and agricultural and forestry waste are decomposed and converted through a co-pyrolysis process. The rational utilization of pyrolysis gas and bio-oil achieves energy recycling and reduces dependence on external energy sources. The entire preparation process reduces greenhouse gas emissions and environmental pollution, with significant environmental benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The present invention provides a flow chart of a method for preparing biochar-based fertilizer by co-pyrolysis of livestock and poultry manure and agricultural and forestry waste. DETAILED DESCRIPTION

[0019] Please refer to Figure 1 .

[0020] Example 1 further illustrates the method for preparing biochar-based fertilizer by co-pyrolysis of livestock and poultry manure and agricultural and forestry wastes proposed in the present invention.

[0021] This embodiment provides a method for preparing biochar-based fertilizer by co-pyrolysis of livestock and poultry manure and agricultural and forestry waste, comprising the following steps: Step 1: Raw material pretreatment; livestock and poultry manure and agricultural and forestry waste are subjected to solid-liquid separation, and mechanical extrusion, centrifugal separation or filtration are used, and the separated liquid portion can be further processed to produce biogas slurry fertilizer; wherein the solid manure portion is crushed together with the agricultural and forestry waste solid portion to increase the reaction contact area of the raw materials in the subsequent pyrolysis process; Step 2: Raw material pyrolysis treatment; the pretreated livestock and poultry manure and agricultural and forestry waste are mixed evenly and then fed into a pyrolysis furnace; pyrolysis is carried out under an inert gas or low-oxygen environment, wherein the pyrolysis temperature is controlled at 400- 700℃, and the pyrolysis time is 1-3h; under this condition, the organic components in the raw materials undergo thermal decomposition reaction to generate biochar products; Step three: Raw material reprocessing; The generated biochar is taken out of the pyrolysis furnace and quickly cooled to room temperature by air cooling or water cooling to avoid further oxidation of the biochar at high temperature, and the biochar is mixed with phosphoric acid solution in proportion, and then filtered and washed to neutrality, and then heated for activation treatment; Step four: Addition of nutrients; According to different soil fertility conditions and crop growth needs, add appropriate amounts of nitrogen, phosphorus, potassium and other macro-element fertilizers and calcium, magnesium, zinc, boron and other trace element fertilizers to the activated biochar.

[0022] In the present invention, in step 1, during the pretreatment of the raw materials, fresh livestock and poultry manure, such as cow dung, pig dung, chicken manure, etc., is mainly collected and temporarily stored in a sealed and well-ventilated container or storage pool to avoid rainwater erosion and the spread of odor; at the same time, various types of agricultural and forestry waste are collected, including but not limited to crop straw (such as corn straw, wheat straw, rice straw), fruit tree branches, forestry pruning waste, wood chips, and agricultural product processing residues (such as rice husks, peanut shells, sugarcane bagasse), etc. The collected agricultural and forestry waste is transported to a designated site for classification and stacking for subsequent processing; among them, livestock and poultry manure contains rich organic matter and nutrients. By converting livestock and poultry manure into organic fertilizer or biogas, returning it to farmland, improving soil structure, reducing the use of chemical fertilizers, promoting sustainable agricultural development and supporting green agricultural development: the resource utilization of livestock and poultry manure is one of the important ways to promote the development of green agriculture. By rationally using livestock and poultry manure and agricultural waste, it can effectively reduce environmental pollution, improve the ecological environment, and make contributions. Therefore, livestock and poultry manure is used as waste. Moreover, scientific treatment of livestock and poultry manure is an important measure to achieve environmental protection, resource conservation and green development of agriculture. It is of great significance to the development of green ecological agriculture, protection of ecological balance and reduction of environmental pollution.

[0023] It should be noted that in step 1, the size of livestock and poultry manure particles reaches 1-5 cm, and agricultural and forestry waste is crushed to a length of 2-10 cm. The purpose of this is to increase the reaction contact area of the raw materials in the subsequent pyrolysis process and improve the pyrolysis efficiency.

[0024] In this embodiment, pre-treated livestock and poultry manure and agricultural and forestry waste are mixed uniformly in a mass ratio of 1:1-3:1 and then fed into a pyrolysis furnace for pyrolysis. During the pyrolysis process, the generated pyrolysis gas is purified and collected.

[0025] In step three, the cooled biochar is further pulverized by mechanical pulverization equipment to a particle size of 0.1-1 mm. In step three, the biochar is mixed with a 10%-30% by mass phosphoric acid solution in a ratio of 1:3-1:5 and stirred at 80-120°C for 2-4 hours. In step three, the activation temperature is 500-700°C, and the activation time is 1-2 hours. The biochar-based fertilizer is obtained by adding the activated biochar and trace elements into a stirring device and stirring for 1-2 hours.

[0026] In the present invention, in step 2, the pyrolysis gas generated during the pyrolysis process is purified and collected. It should be noted that the pyrolysis gas generated during the pyrolysis process mainly contains combustible gases such as carbon monoxide, hydrogen, and methane, which can be used as heating fuel in the pyrolysis furnace after purification to achieve energy recycling; the bio-oil is collected and can be further processed and refined for the preparation of biodiesel or other chemical products.

[0027] Working principle:

[0028] Step 1: Raw material pretreatment

[0029] The solid-liquid separation of livestock and poultry manure and agricultural and forestry waste is carried out by mechanical extrusion, centrifugal separation or filtration. The separated liquid portion can be further processed for the production of biogas slurry fertilizer. The solid manure portion is pulverized together with the agricultural and forestry waste solids to increase the reaction contact area of the raw materials in the subsequent pyrolysis process.

[0030] Step 2: Pyrolysis of raw materials

[0031] The pre-treated livestock and poultry manure and agricultural and forestry waste are mixed evenly and then fed into a pyrolysis furnace. Pyrolysis is carried out under an inert gas or low-oxygen environment, with the pyrolysis temperature controlled at 400-700°C and the pyrolysis time being 1-3 hours. Under these conditions, the organic components in the raw materials undergo thermal decomposition reactions to produce biochar products.

[0032] Step 3: Raw material reprocessing

[0033] The generated biochar is removed from the pyrolysis furnace and quickly cooled to room temperature by air cooling or water cooling to prevent further oxidation of the biochar at high temperature. The biochar is mixed with phosphoric acid solution in proportion, filtered, washed to neutrality, and then heated for activation.

[0034] Step 4: Adding nutrients

[0035] According to different soil fertility conditions and crop growth needs, appropriate amounts of nitrogen, phosphorus, potassium and other macro-element fertilizers as well as calcium, magnesium, zinc, boron and other micro-element fertilizers are added to the activated biochar.

[0036] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiment. All technical solutions based on the concept of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, various improvements and modifications that do not depart from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing biochar-based fertilizer by co-pyrolysis of livestock and poultry manure and agricultural and forestry waste, characterized in that: The steps include: Step 1: Raw material pretreatment The solid-liquid separation of livestock and poultry manure and agricultural and forestry waste is carried out by mechanical extrusion, centrifugal separation or filtration. The separated liquid portion can be further processed for the production of biogas slurry fertilizer. The solid manure portion is pulverized together with the agricultural and forestry waste solids to increase the reaction contact area of the raw materials in the subsequent pyrolysis process. Step 2: Pyrolysis of raw materials The pre-treated livestock and poultry manure and agricultural and forestry waste are mixed evenly and then fed into a pyrolysis furnace. Pyrolysis is carried out under an inert gas or low-oxygen environment, with the pyrolysis temperature controlled at 400-700°C and the pyrolysis time being 1-3 hours. Under these conditions, the organic components in the raw materials undergo thermal decomposition reactions to produce biochar products. Step 3: Raw material reprocessing The generated biochar is removed from the pyrolysis furnace and quickly cooled to room temperature by air cooling or water cooling to prevent further oxidation of the biochar at high temperature. The biochar is mixed with phosphoric acid solution in proportion, filtered, washed to neutrality, and then heated for activation. Step 4: Adding nutrients According to different soil fertility conditions and crop growth needs, appropriate amounts of nitrogen, phosphorus, potassium and other macro-element fertilizers as well as calcium, magnesium, zinc, boron and other micro-element fertilizers are added to the activated biochar.

2. The method for preparing biochar-based fertilizer by co-pyrolysis of livestock and poultry manure and agricultural and forestry waste according to claim 1, characterized in that: In the step 1, the size of livestock and poultry manure particles reaches 1-5 cm, and agricultural and forestry waste is crushed to a length of 2-10 cm.

3. The method for preparing biochar-based fertilizer by co-pyrolysis of livestock and poultry manure and agricultural and forestry waste according to claim 2, characterized in that: The pre-treated livestock and poultry manure and agricultural and forestry waste are mixed evenly in a mass ratio of 1:1-3:1 and then fed into a pyrolysis furnace for pyrolysis. During the pyrolysis process, the generated pyrolysis gas is purified and collected.

4. The method for preparing biochar-based fertilizer by co-pyrolysis of livestock and poultry manure and agricultural and forestry waste according to claim 3, characterized in that: In the step three, the cooled biochar is further crushed by mechanical crushing equipment to a particle size of 0.1-1 mm.

5. The method for preparing biochar-based fertilizer by co-pyrolysis of livestock and poultry manure and agricultural and forestry waste according to claim 4, characterized in that: In the step three, the biochar is mixed with a phosphoric acid solution having a mass fraction of 10% to 30% in a ratio of 1:3 to 1:5, and the mixture is stirred and immersed at 80 to 120° C. for 2 to 4 hours.

6. The method for preparing biochar-based fertilizer by co-pyrolysis of livestock and poultry manure and agricultural and forestry waste according to claim 5, characterized in that: In the step 3, the temperature of the activation treatment is 500-700° C., and the activation time is 1-2 hours.

7. The method for preparing biochar-based fertilizer by co-pyrolysis of livestock and poultry manure and agricultural and forestry waste according to claim 6, characterized in that: In the step 4, the activated biochar and trace elements are respectively put into a stirring device and stirred for 1-2 hours to obtain a biochar-based fertilizer.

8. The method for preparing biochar-based fertilizer by co-pyrolysis of livestock and poultry manure and agricultural and forestry waste according to claim 7, characterized in that: In the step 2, during the pyrolysis process, the generated pyrolysis gas is purified and collected.

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