TWI724878B - A method for converting livestock waste into biochar - Google Patents

Abstract

The invention discloses a method for converting livestock waste into biochar, which comprises the following steps of: (1) performing a water removal treatment on the livestock waste; (2) performing a crushing treatment on the the livestock waste after the water removal treatment; (3) performing a microwave heating treatment on the livestock waste after crushing treatment under a low oxygen condition; (4) decomposing the livestock waste during the microwave heating treatment into a gaseous substance and a solid matter. Before microwave heating, the method only needs to remove water, crush and add microwave absorbing materials to the livestock waste, thus the method is simple and convenient, and the solid, liquid and gas products produced by decomposition are all available resources.

Description

Method for making biochar from wastes of poultry and livestock

The present invention relates to a method for turning organic waste into renewable resources, and more particularly to a method for producing biochar by microwave thermal cracking of waste generated by poultry and livestock.

Common poultry and livestock such as chickens, ducks, geese, pigs, cattle or sheep are the protein sources for humans' daily dining table. Therefore, a considerable number of breeding and slaughter sites are required, and a considerable amount of livestock waste is also generated. Poultry and livestock waste that has not been properly treated will not only cause mosquitoes and flies to breed and spread of diseases, affect environmental sanitation, and cause problems in epidemic prevention. The conventional method of poultry waste treatment is composting and burying, using the microorganisms in the soil to ferment the poultry waste. However, the process of composting and burying takes a long time, and there are concerns about biosafety and soil and groundwater pollution. Another conventional method of treating livestock waste is incineration, which eliminates air pollution such as odor and may even produce harmful gases, such as the poison of the century-Dioxin.

On the other hand, biochar is a carbonized material that is mainly carbon after the decomposition of organic biomass. After the biochar is mixed with the soil, it can not only improve the physical and chemical properties of the soil, increase the productivity of the soil, but also adsorb heavy metal ions and organic pollutants in the soil. Due to the stable structure of biological carbon, organic matter can be stored in the soil for a long time, achieving the effect of increasing soil carbon sequestration. Therefore, biochar has both resource reuse and environmental carbon reduction effects. If poultry wastes such as chickens, ducks, geese, pigs, cattle or sheep are properly recycled and used to make biological carbon return to land use, it can not only improve soil fertility, solve the environmental problems of chemical fertilizer use, and reduce carbon sequestration at the same time. Carbon function.

The conventional way to produce biochar is to use kilns, distillers and other equipment to decompose organic substances, especially agricultural and forestry wastes, under oxygen-limited environment, and involve changes in chemical composition and physical phase. Irreversible reaction. When organic matter is decomposed at high temperature, the first step will release combustible gas (hydrogen and methane, etc.), then release tar, and finally the main body of biochar after carbonization. However, the current conventional bio-carbon production methods have low thermal efficiency due to the use of heating or electric kilns and distillers, resulting in poor production efficiency of bio-carbon. The production process not only consumes energy, but also has problems such as smoke, odor and tar. To be resolved. In addition, there is currently no better way to produce biochar from waste generated by poultry and livestock.

In view of this, it is necessary to propose a rapid and environmentally friendly method for turning livestock waste into biochar.

In order to solve the above problems, the main purpose of the present invention is to provide a method for processing livestock waste, which is to conduct microwave pyrolysis of organic waste generated by livestock and obtain solid products, that is, biochar, which can also be obtained during the process. Liquid products, namely biomass oil, and gas products, namely syngas. In order to effectively obtain high-quality biochar and avoid excessive tar and biogas production, the present invention proposes two-stage microwave power and heating time control.

In order to achieve the purpose of the present invention, the present invention provides a method for turning livestock waste into biochar, which is characterized by including the following steps: step (1), subject a poultry waste to a water removal treatment; step (2) ), the dewatered livestock waste is subjected to a crushing treatment; step (3), the crushed livestock waste is subjected to a microwave heating treatment under a low oxygen condition; and step (4), The poultry waste processed by the microwave heating is decomposed into a gaseous substance and a solid substance.

According to one feature of the present invention, in step (1), the moisture content of the livestock waste is reduced to 60-30%.

According to a feature of the present invention, the water removal treatment system in step (1) is selected from one of mechanical dehydration or dry dehydration.

According to a feature of the present invention, the crushing treatment in step (2) is to crush livestock waste to less than 10 mm.

According to a feature of the present invention, step (2) further includes: adding a microwave absorbing substance.

According to a feature of the present invention, the microwave absorbing material is selected from carbonaceous material, metal particles or metal oxide powder.

According to a feature of the present invention, the oxygen-reduced condition in step (3) is selected from one of using restricted gas inlet design or inert gas.

According to a feature of the present invention, in the step (3), the microwave heating treatment is to heat the crushed poultry waste under the low oxygen condition to 400-1200°C.

According to a feature of the present invention, the microwave heating treatment adopts a microwave power with a frequency of 915 MHz or 2450 MHz.

According to a feature of the present invention, the solid matter after decomposition into the decomposition reaction is collected and subjected to a subsequent treatment to generate a biochar material.

The method for preparing biochar from poultry wastes of the present invention has the following effects: 1 the heat efficiency of microwave heating treatment is extremely high, and the production efficiency of biochar is good; 2 the energy consumption of microwave heating treatment is extremely low, and there is no smoke and odor Problems such as smell; 3 The biochar made by microwave heating has high carbon content and higher quality than traditional heating methods.

In order to make the above and other objects, features, and advantages of the present invention more comprehensible, several preferred embodiments are listed below in conjunction with the accompanying drawings, which are described in detail as follows.

Fig. 1 shows a flow chart of a method for producing biochar from livestock waste according to the present invention.

Although the present invention can be embodied in different forms of embodiments, those shown in the drawings and described herein are preferred embodiments of the present invention. Those familiar with the art will understand that the devices and methods specifically described herein and illustrated in the drawings are considered as examples of the present invention, non-limiting exemplary embodiments, and the scope of the present invention is only within the scope of the patent application. Be defined. The features illustrated or described in combination with an exemplary embodiment can be combined with features of other embodiments. Such modifications and changes will be included in the scope of the present invention.

In order to achieve the objective of the present invention, the present invention provides a method for turning poultry and livestock waste into biochar. Please refer to FIG. 1, which shows a flow chart of a method for producing biochar from livestock waste according to the present invention. The method includes the following steps: step (1), a dewatering treatment is performed on a poultry waste; step (2), a crushing treatment is performed on the dewatered poultry waste; step (3), the The crushed livestock waste is subjected to a microwave heating treatment under a low-oxygen condition; and in step (4), the microwave-heated livestock waste is decomposed into a gaseous substance and a solid substance.

Poultry and livestock include chickens, ducks, geese, pigs, cattle or sheep, etc., while livestock waste refers to all kinds of waste generated when poultry farming or slaughtering poultry and livestock, including sludge or sewage . Such as poultry excrement, feed residues, etc. when raising chickens, ducks, geese, pigs, cattle or sheep, or Poultry feathers, blood, leftovers, inedible parts, etc. during slaughter. The moisture content of untreated livestock waste may be as high as 100%.

In step (1), first reduce the moisture content of the livestock waste to 60-30%. Preferably, the moisture content of the livestock waste is reduced to 50-30%, which can shorten the time of the subsequent thermal cracking reaction.

In step (1), the water removal treatment refers to reducing the moisture content of the livestock waste, which can be selected from one of mechanical dehydration or dry dehydration. The principle of mechanical dehydration can be divided into three categories: vacuum filtration dehydration, press filtration dehydration and centrifugal dehydration. Vacuum filtration dehydration is also called decompression filtration. The air part of the lower cavity is removed by the air suction and decompression device, causing a pressure difference, so that the liquid is filtered under the dual action of gravity and pressure difference to achieve rapid separation of liquid and solid. Purpose of sediment; filter press dewatering is composed of frame, filter plate, filter cloth and other parts. When the processed material is pressed into contact with the filter cloth, the larger particles will form a bridging effect in front of the filter cloth hole to form a filter cake. Solid-liquid separation effect; centrifugal dehydration mainly uses the centrifugal force generated by high-speed rotation, solid particles are thrown on the inner wall to form a solid layer, thereby achieving the dehydration effect. Drying and dehydration adopts heat treatment methods, such as exposure drying, hot air drying, stove heating, electric heating drying, microwave drying, etc., generally drying to a high temperature of 100°C to 150°C, and the time is about 10 minutes to 30 minutes, which can make the livestock waste The water evaporates to achieve the purpose of removing water from the livestock waste. Preferably, in order to achieve rapid water removal, in an embodiment of the present invention, the water removal treatment system adopts microwave drying to reduce the moisture content of the livestock waste to 60-30%.

In step (2), the crushing processing system crushes the livestock waste to a smaller size. Since livestock waste is not a homogeneous material, different shapes and structures will affect heat transfer, thereby affecting the thermal cracking effect. Therefore, larger livestock waste must be crushed to a size that can be uniformly mixed. The crushing method adopts mechanical treatment, and can choose crusher, crusher and mincer, etc. The crushing treatment system crushes the livestock waste to 10 mm or less, preferably to 5 mm or less.

Step (2) further includes: adding a microwave absorbing substance. The microwave absorbing material is selected from carbonaceous materials, metal particles or metal oxide powders, and mixtures thereof. The microwave absorbing material can absorb the energy of the microwave, and by uniformly mixing with the crushed livestock waste, the crushed livestock waste can be uniformly heated and the reaction rate is accelerated. Among them, carbon-containing substances can be carbon black, stone mill, activated carbon and carbon fiber, etc., and their mixtures; metal particles can be carbon iron, nickel copper zinc ferrite magnets, nickel zinc ferrite magnets, manganese zinc ferrite magnets or related metals Substances or nano-metal substances, or mixtures thereof; metal oxide powders can be magnesium oxide, calcium oxide, strontium oxide, barium oxide, aluminum oxide, silicon oxide, iron oxide, zirconium oxide, vanadium oxide, iron oxide, titanium oxide, Manganese oxide, cobalt oxide, nickel oxide, magnesium carbonate, calcium carbonate, strontium carbonate, barium carbonate, aluminum carbonate, etc., oxides or carbon oxide materials with high dielectric constant, and mixtures thereof. The addition amount of the microwave absorbing material in the livestock waste after the crushing treatment is between 2% and 30% of the weight percentage of the livestock waste after the crushing treatment. Preferably, the amount of the microwave absorbing material added to the livestock waste after the crushing treatment is between 5% and 10% of the weight percentage of the livestock waste after the crushing treatment. It should be noted that the addition of a microwave absorbing substance can be added before, during or after the crushing treatment of the livestock waste, that is, before the step (3) is performed.

In step (3), the low-oxygen condition is selected from one of using restricted gas inlet design or inert gas. Thermal cracking is a thermochemical reaction process that decomposes organic substances into biological carbon, biological oil and combustible fuel under high temperature, oxygen-free or low-oxygen conditions. The low-oxygen condition means that during the heating process, the amount of oxygen in the heating chamber is less than that of ordinary air. The low-oxygen condition means that the amount of oxygen is less than one-third of the amount of ordinary air. Preferably, the The low-oxygen condition means that the amount of oxygen is less than one-tenth of the amount of ordinary air. The low-oxygen condition can also be achieved through a restricted air intake design, that is, during the reaction process of the heating chamber, only air is pumped, but not air. By starting oxygen consumption, there is no subsequent oxygen supplement to reach the restricted intake design. The oxygen-less condition can also be continuously fed with inert gas, such as nitrogen or argon, whose flow rate is proportional to the capacity of the heating chamber.

It should be noted that step (1) and step (2) can be interchanged, that is, the crushing treatment can be carried out first, and then the water removal treatment can be carried out, which does not change the spirit of the present invention and the result of biochar production. However, if step (1) and step (2) are interchanged, adding a microwave absorbing substance is still performed after step (2) and before step (3).

In step (3), the microwave heating treatment is to heat the crushed livestock waste to 400-900°C under the low oxygen condition. Microwave is an electromagnetic wave. Microwave heating uses the principle of radiation to penetrate the surface of the medium and enter the inside of the material. The medium converts the absorbed microwave energy into heat to achieve the purpose of heating. The pyrolysis of the crushed poultry waste starts to react in a high temperature and low oxygen state. The heating temperature is adjusted according to different reactants and the types of products to be obtained. The range is controlled between 400-1200°C and the heating is continued. a period of time. Preferably, the microwave heating treatment is to heat the crushed livestock waste under the low-oxygen condition to between 500-800°C. The required microwave power is related to the capacity of the heating chamber and the weight of the processed livestock waste. In the present invention, in order to achieve an effective temperature range, the range of the microwave power of the microwave heating treatment is: the weight of the livestock waste Use 4KW to 6KW below 100 kg, use 6KW to 9KW when the weight of livestock waste is 100 kg to 300 kg, and use 9KW to 15KW when the weight of livestock waste is 300 kg to 1000 kg.

It should be noted that in order to effectively obtain high-quality biochar and avoid excessive tar and biogas production, step (3) includes: when the temperature is below 400 ℃, use the first microwave power, and at the temperature At 400°C, heating is continued for a first period of time; when the temperature exceeds 400°C, the second microwave power is used, and when the temperature reaches the final set temperature, heating is continued for a second period of time. The first type of microwave power is less than the second type of microwave power. For example, when the weight of poultry waste is 100 kg to 300 kg, use 6KW to 9KW, when the temperature is below 400℃, the first microwave power is 6KW, and when the temperature is 400℃, continue heating for 10 minutes; At 400°C, the second microwave power is 9KW, and when the temperature reaches the final set temperature, heating is continued for 5 minutes. This two-stage microwave power and heating time control method can be easily controlled by the electric control of the cavity. The design achieves and effectively obtains high-quality biochar, and avoids excessive tar and biogas production. The microwave heating treatment uses a microwave power at a frequency of 915 MHz or 2450 MHz.

In step (4), the microwave-heated livestock waste is decomposed into a gaseous substance and a solid substance. After subsequent condensation, the gaseous substance is divided into liquid products, namely biomass oil, and gas products, namely synthesis gas (mainly hydrogen, acetanilide and carbon monoxide). The solid matter decomposed by the microwave heating treatment of livestock waste is collected, and a subsequent treatment is performed to generate a biological carbon material. The follow-up treatment is that after the microwave heating treatment cools down to normal temperature, the solid matter is taken out from the discharge port of the heating chamber, and the follow-up treatment is performed, such as washing with clean water to remove impurities and drying, to obtain a biochar material.

In the first embodiment of the method for converting livestock waste into biochar of the present invention, the obtained 50Kg livestock waste is dewatered by a centrifugal dewatering machine that is mechanically dewatered to a moisture content of 50%. The dewatered poultry waste is crushed to a size of 10 mm with a crusher. The crushed poultry waste is mixed with 10% carbon black, placed in an oxygen-free environment with inert gas, and subjected to microwave heating treatment. During the microwave heating process, the temperature is heated and maintained at 500°C. When the temperature is below 400℃, the first microwave power is 4KW, and when the temperature is 400℃, continue heating for 10 minutes; when the temperature exceeds 400℃, the second microwave power is 6KW, and when the temperature reaches 500℃, Continue heating for 5 minutes. After the microwave heating treatment equipment is cooled to normal temperature, the decomposed solid substance is taken out from the discharge port, washed with clean water to remove impurities and dried, and then the bio-carbon material is obtained.

In the second embodiment of the method for converting livestock waste into biochar of the present invention, 200Kg of the obtained livestock waste is dried and dehydrated in a large oven to remove water to a moisture content of 40%. The dewatered poultry waste is crushed to a size of 5mm with a crusher. The crushed poultry waste is mixed with 10% activated carbon powder, placed in a restricted oxygen environment where gas is restricted, and subjected to microwave heating treatment. During the microwave heating process, the temperature is heated and maintained at 600°C. When the temperature is below 400℃, the first microwave power is 6KW, and when the temperature is 400℃, continue heating for 10 minutes; when the temperature exceeds 400℃, the second microwave power is 9KW, and when the temperature reaches 600℃, Continue heating for 5 minutes. After the microwave heating treatment is cooled to normal temperature, the decomposed solid material is taken out from the discharge port of the heating cavity and collected, washed with clean water to remove impurities and dried, and then the biochar material is obtained.

The method for preparing biochar from poultry wastes of the present invention has the following effects: 1 the heat efficiency of microwave heating treatment is extremely high, and the production efficiency of biochar is good; 2 the energy consumption of microwave heating treatment is extremely low, and there is no smoke and odor Problems such as smell; 3 The biochar made by microwave heating has high carbon content and higher quality than traditional heating methods.

Although the present invention has been disclosed in the foregoing preferred embodiments, it is not intended to limit the present invention. Anyone familiar with the art can make various changes and modifications without departing from the spirit and scope of the present invention. As explained above, various modifications and changes can be made without destroying the spirit of the invention. Therefore, the scope of protection of the present invention shall be subject to those defined by the attached patent scope.

Claims (10)

A method for turning livestock waste into biochar includes the following steps: step (1), subject a poultry waste to a dewatering treatment; step (2), subject the dewatered poultry waste to A crushing treatment; step (3), the crushed livestock waste is subjected to a microwave heating treatment under a low oxygen condition; and step (4), the microwave heating treatment of the livestock waste is decomposed into a gaseous state A substance and a solid substance, the gas substance mainly contains hydrogen, formazan and carbon monoxide, and the solid substance is mainly a biocarbon material; among them, when the temperature is below 400℃, the first type of microwave power is used, and when the temperature is 400℃ , Continue heating for a first period of time, and when the temperature exceeds 400℃, use the second type of microwave power, when the temperature reaches the final set temperature, continue to heat for a second period of time; and the first type of microwave power is less than the second Kind of microwave power. A method for turning livestock waste into biochar as in claim 1, wherein in step (1), the moisture content of the livestock waste is reduced to 60-30%. A method for converting livestock waste into biochar as in claim 1, wherein the water removal treatment in step (1) is selected from one of mechanical dehydration or dry dehydration. A method for converting livestock waste into biochar as in claim 1, wherein the crushing treatment in step (2) is to crush the livestock waste to less than 10 mm. Such as claim 1, a method for turning livestock waste into biochar, wherein step (2) further comprises: adding a microwave absorbing material. According to claim 5, a method for making biochar from livestock waste, wherein the microwave absorbing material is selected from carbonaceous material, metal particles or metal oxide powder. As claimed in claim 1, a method for converting livestock waste into biochar, wherein the oxygen-reduced condition in step (3) is selected from one of using restricted air intake design or inert gas. According to claim 1, a method for converting livestock waste into biochar, wherein the microwave heating treatment is to heat the crushed livestock waste to 400-1200°C under the low oxygen condition. Such as claim 5, a method for turning poultry waste into bio-carbon, wherein the metal particles can be carbon iron, nickel-copper-zinc ferrite magnets, nickel-zinc ferrite magnets, manganese-zinc ferrite magnets or related metal substances Or nanometal substances, or mixtures thereof. Such as claim 1, a method for turning livestock waste into biochar, wherein the solid matter after the decomposition reaction is collected and then subjected to a subsequent treatment to generate a biochar material.

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