TW202142327A - A method for converting organic waste into energy - Google Patents

Abstract

The invention discloses a method for converting organic waste into energy, which includes the following steps (1), a pre-treatment of a poultry organic waste; step (2), performing the pre-treatment of organic waste with a heating process to a maximum temperature under a low oxygen condition, wherein a first heating rate is used as the temperature is below 600 DEG C, and a second heating rate is used as the temperature exceeds 600DEG; step (3), decomposing the organic waste after the heating process into a gas substance. The method is controlled by a two-stage heating rate, and the solid, liquid and gas products produced by the decomposition are all available resources. In particular, the gas product, being the energy available as fuel, can be therefore increased.

Description

A method for generating energy from organic waste

The present invention relates to a method for turning organic waste into renewable resources, and more particularly to a method for generating energy by microwave thermal cracking of organic waste.

Common organic substances are needed by humans, so a considerable amount of organic waste is also generated. Organic 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 organic waste treatment method is composting and burying, and the organic waste is fermented by the microorganisms in the soil. However, the process of composting and burying takes a long time to process, and there are concerns about biosafety and pollution of soil and groundwater. Another conventional method of processing organic waste is incineration, which eliminates air pollution such as odor and may even produce harmful gases, such as Toxin of the Century-Dioxin.

On the other hand, the organic biomass reacts with water vapor under low oxygen conditions and high temperature conditions, and can be transformed into a mixed gas material mainly composed of hydrogen, carbon monoxide, carbon dioxide and methane. This mixed gas is called synthesis gas (syngas or synthesis gas), which itself is a fuel that can be used for power generation or processing to become a synthetic fuel. After the synthesis gas is purified, the acid gas that causes equipment corrosion and the tar that cause equipment clogging can be removed, and it can be used in more efficient gas boilers, internal combustion engines or gas turbines to recover electricity. In particular, generating energy from organic waste is a technology that achieves "carbon neutral". Therefore, proper recycling of organic waste is used to make synthesis gas, which has the effect of resource reuse.

The conventional way to produce syngas is to use gasification technology to react carbon-containing raw materials, such as coal, natural gas, petroleum, oil refining residues, and organic substances, with water vapor under restricted oxygen and high temperature environments. Combustible syngas gas, but also by-products such as tar. However, the currently known synthesis gas production method is gasification technology, which is divided into gasification melting and gasification combustion according to its reaction temperature. The actual gasification melting plant is limited by the high operating cost and high temperature operation, and the equipment failure rate is high, and the annual operation rate is usually less than 80%; while the gasification combustion technology requires high homogeneity of the feed waste, and the treatment water content is too high. High waste will reduce the calorific value of syngas. Therefore, the gasification technology has a low tolerance for waste volatility, the energy loss of pre-treatment facilities needs to be reassessed, and problems such as tar production and dioxin have yet to be resolved. In addition, there is currently no better way to produce synthesis gas from organically generated waste.

In view of this, it is necessary to propose a fast and environmentally friendly method for turning organic waste into synthesis gas.

In order to solve the above-mentioned problems, the main purpose of the present invention is to provide an organic waste treatment method, which is to perform microwave thermal cracking of organic wastes and obtain gas products, namely syngas. In order to effectively obtain high-volume and high-calorific value syngas and avoid excessive tar and dioxin generation, the present invention proposes two-stage microwave power and heating time control.

In order to achieve the objective of the present invention, the present invention provides a method for generating energy from organic waste, which is characterized by including the following steps:

In step (1), an organic waste is subjected to a pre-treatment;

In step (2), the pre-treated organic waste is heated to a maximum temperature under a low-oxygen condition. When the temperature is below 600°C, a first heating rate is used, and when the temperature exceeds 600°C When, use a second heating rate;

In step (3), the heat-treated organic waste is decomposed into a gaseous substance.

According to a feature of the present invention, the heat treatment in step (2) is to heat the pre-treated organic waste under the low oxygen condition to a maximum temperature of 800-1000°C.

According to a feature of the present invention, the first heating rate in step (2) is greater than the second heating rate.

According to a feature of the present invention, the first heating rate in step (2) is more than 1.5 times the second heating rate.

According to a feature of the present invention, the pretreatment in step (1) is to perform a water removal treatment and a crushing treatment on the organic waste.

According to a feature of the present invention, the water removal treatment system is selected from one of mechanical dehydration or dry dehydration, and the moisture content of the organic waste is reduced to 70-50%.

According to one feature of the present invention, the crushing treatment system crushes the organic waste to less than 10 mm.

According to a feature of the present invention, the oxygen-reduced condition in step (2) is selected from one of using restricted gas inlet design or inert gas.

According to a feature of the present invention, the heating treatment in step (2) adopts microwave heating treatment.

According to a feature of the present invention, when the temperature is below 600°C, a first type of microwave power is used, and when the temperature exceeds 600°C, a second type of microwave power is used, and the first type of microwave power is greater than the second type Microwave power.

The method for preparing synthetic gas from organic waste of the present invention has the following effects:

1 The heat efficiency of microwave heating treatment is extremely high, and the production efficiency of synthesis gas is good;

2 The energy consumption of microwave heating treatment is extremely low, and there are no problems such as smoke and odor;

3 The use of microwave heating to treat organic waste, because it can quickly heat up, has a high tolerance for waste volatility, and can avoid the temperature range of 200-400 ℃ caused by dioxin.

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.

Figure 1 shows a flow chart of a method for generating energy from organic 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 generating energy from organic waste. Please refer to FIG. 1, which shows a flow chart of a method for generating energy from organic waste according to the present invention. The method includes the following steps:

In step (1), an organic waste is subjected to a pre-treatment;

In step (2), the pre-treated organic waste is heated to a maximum temperature under a low-oxygen condition. When the temperature is below 600°C, a first heating rate is used, and when the temperature exceeds 600°C When, use a second heating rate;

In step (3), the heat-treated organic waste is decomposed into a gaseous substance.

Organic waste generally refers to the residues of animals, plants, microorganisms or wastes produced by their natural activities, such as useless, unnecessary or discarded substances generated during production or consumption, including gaseous, liquid and solid wastes. The types of organic waste can be divided into business organic waste, There are three major categories of agricultural organic waste and people's livelihood organic waste. Business organic waste comes from: food factories, wineries, slaughterhouses, restaurants, markets, hospitals, restaurants, biological sludge...etc. Agricultural organic waste comes from: gardens, fruits and vegetables, mushroom farms, farms, forestry, chicken farms, cattle farms, sheep farms... etc. People's livelihood organic waste comes from: kitchen waste, government agencies, military units, schools, prisons, communities... etc. Among them, 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. For example, poultry excrement and feed residues from chickens, ducks, geese, pigs, cattle or sheep, or poultry feathers, blood, leftovers, and inedible parts during slaughter. The moisture content of untreated livestock waste may be as high as 100%.

In step (1), the pre-treatment system performs the dewatering treatment to the crushing treatment of the organic waste. First reduce the moisture content of the organic waste to 70-50%, which can shorten the subsequent heating time to 600°C, and subsequently react with water vapor to generate combustible gas. The appropriate water content needs to be controlled. Preferably, the organic waste The moisture content of the waste is reduced to 65-50% to produce combustible gas with higher calorific value. And crush the dewatered organic waste to less than 10mm, and increase the uniformity of the reactant during heating.

In step (1), the water removal treatment refers to reducing the moisture content of the organic 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, which causes 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 and brought 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 is mainly through the centrifugal force generated by high-speed rotation, solid particles are thrown to the inner wall to form a solid layer, thereby achieving the dehydration effect. Drying and dehydration adopt heat treatment methods, such as exposure drying, hot air drying, stove heating, electric heating drying, microwave drying, etc., generally drying to 100°C to 150°C High temperature, about 10 minutes to 30 minutes, can evaporate the organic waste water to achieve the purpose of removing water from the organic 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 organic waste to 70-50%.

In step (1), the crushing treatment system crushes the organic waste to a smaller size. Since organic waste is not a homogeneous material, different shapes and structures will affect heat transfer and thus the thermal cracking effect. Therefore, larger organic 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 organic waste to less than 10 mm, preferably to less than 5 mm.

It should be noted that the pretreatment in step (1) does not limit the dewatering treatment first, and then the crushing treatment, that is, the crushing treatment can be performed first, and then the dewatering treatment is performed, which does not change the spirit of the present invention, but also changes the composition The result of qi.

Wherein, the heat treatment in step (2) is to heat the pre-treated organic waste under the low oxygen condition to a maximum temperature of 800-1000°C. And in step (2), by controlling the microwave power, the first heating rate is greater than the second heating rate. In step (2), the first heating rate is 10°C/sec or more; preferably, the first heating rate is 30°C/sec or more; most preferably, the first heating rate is 50°C/above per second. The first heating rate is more than 1.5 times the second heating rate, preferably, the first heating rate is more than 2 times the second heating rate. Thereby, the ratio of decomposition of the heat-treated organic waste into the gaseous substance can be increased.

In step (2), 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 synthesis gas, bio-oil and combustible gas 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 that of ordinary air. Preferably, the Low oxygen condition refers to the amount of oxygen It is less than one-tenth of the amount of oxygen in general air. The oxygen-reduced 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 no air is entered. 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.

The heat treatment device in step (2) is selected from a kiln, a high temperature furnace, a cracking furnace, a gasification furnace or a microwave heating device. Kilns can be divided into wood kilns, electric kilns, and gas kilns according to their energy sources. The heating speed is slow, and it requires a lot of energy, and the gas products are not easy to collect. The high temperature furnace is a common warming device. Its basic structure is to add heaters around the reaction tank to achieve high temperature. However, there is a temperature gradient in the high temperature furnace and the heating is not uniform. Cracking furnaces can be divided into tube type and electric heating type. The fluid in the tube type cracking furnace flows along the solid wall, forming a flow boundary layer with heat transfer resistance on the inner wall of the furnace, and the tube wall is prone to coking, causing heat transfer loss; The electrothermal cracking furnace has uneven heating due to the temperature gradient in the furnace. Gasification furnaces are divided into two types: gasification melting and gasification combustion according to their reaction temperature. Gasification melting is limited by the high operating cost and high temperature operation, the equipment failure rate is high, and the annual operation rate is usually less than 80%; and In addition to gasification and combustion requiring high homogeneity of the feed, the output of fly ash produced will be two to three times higher than that of incineration treatment technology, which requires the use of dust collectors to capture and collect and perform subsequent processing. Preferably, the present invention uses microwave heating equipment, which is different from general traditional heating procedures. The energy is transferred from the surface of the material to the inside of the material in the form of conduction, convection or radiation, which is prone to uneven heating. Microwaves penetrate molecules. The force is transferred in the electromagnetic field, which is an energy conversion process that converts the electromagnetic field into heat. The substance is transferred from the inside of the substance to the surface of the substance through absorption and reflection, and the heating is more uniform. Moreover, the microwave heating technology heats up quickly, which is more energy-efficient than other electric heating equipment.

In step (2), the heating treatment device is a microwave heating device. In the microwave heating treatment, the crushed organic waste is heated to 600-1000°C under the low oxygen condition. Microwave is an electromagnetic wave. Microwave heating uses the principle of radiation to enter the substance through the surface of the medium. The medium converts the absorbed microwave energy into heat to achieve the purpose of heating. Preferably, the Microwave heating is to heat the crushed organic waste to between 600-900°C under the low oxygen condition to obtain gas products with higher calorific value. The required microwave power is related to the capacity of the heating chamber and the weight of the organic waste to be processed. In the present invention, in order to achieve an effective temperature range, the microwave power of the microwave heating treatment is in the range of 100 Use 4KW to 6KW for weight below kilogram, 6KW to 9KW for organic waste weight of 100 kg to 300 kg, and 9KW to 15KW for organic waste weight of 300 kg to 1000 kg.

It should be noted that, in order to effectively obtain high-quality syngas and avoid excessive tar and other by-products, step (2) includes: when the temperature is below 600°C, use the first microwave power to control the shortening of the first microwave power. A period of heating time makes the temperature rise rapidly to 600°C; when the temperature exceeds 600°C, the second microwave power is used, and before the temperature reaches the final set temperature, the slow heating is continued for a second period of time. When the temperature is below 600°C, a first type of microwave power is used, and when the temperature exceeds 600°C, a second type of microwave power is used, and the first type of microwave power is greater than the second type of microwave power.

For example, when the weight of organic waste is between 100 kg and 300 kg, use 6KW to 9KW. When the temperature is below 600°C, the first microwave power is 9KW; when the temperature exceeds 600°C, the second microwave power is 6KW. And before the temperature reaches the final set temperature, continue to slowly heat to reach the final set temperature. This two-stage microwave power and heating time control method can be easily achieved by the electronic control design of the cavity, and can effectively obtain high-quality syngas, and avoid excessive tar and other by-products. The microwave heating treatment uses a microwave power at a frequency of 915 MHz or 2450 MHz.

In step (3), the gaseous substance decomposed after the reaction is collected and then subjected to a subsequent treatment to generate an energy-generating material. Among them, the non-condensable gaseous substance refers to the synthesis gas, and the subsequent processing is selected from the synthesis gas that can be directly burned to generate energy for use in power machinery or power generation; it can be used through the Fischer-Tepsch reaction (Fischer -Tropsch process) is made into synthetic fuel; or after purification treatment, acid gas that will cause equipment corrosion and cause equipment Clogged tar and other impurities are removed, so it can be used in more efficient gas boilers, internal combustion engines or gas turbines to recover electricity.

The condensable gaseous substance undergoes subsequent condensation treatment to form a liquid product, that is, biomass oil, which is refined. The most common process is Transesterification to obtain Biodiesel. It can replace petrochemical diesel as engine or boiler fuel, and has the advantages of high combustion efficiency, low exhaust pollution, good lubricity, and low carbon.

In the first embodiment of the method of making organic waste into synthesis gas of the present invention, the obtained 50Kg organic waste is dewatered by a centrifugal dehydrator for mechanical dehydration to a moisture content of 60%. The organic waste that has been dewatered is crushed to a size of 10 mm with a crusher. The organic waste after the crushing treatment is placed in an oxygen-free environment in which inert gas is introduced, and subjected to microwave heating treatment, and the microwave heating treatment process finally reaches the target temperature of 900°C. When the temperature is below 600℃, the power of the first microwave is 6KW; when the temperature exceeds 600℃, the power of the second microwave is 4KW, and it will continue to slowly heat up to 900℃ before the temperature reaches 900℃. The microwave heating processing equipment is connected to the gas collection device, and the gas is passed through the condensing device to collect the bio-oil; the non-condensable gas is collected to the storage container through the conduit, and the syngas material is obtained.

In the second embodiment of the method of making organic waste into synthesis gas of the present invention, 200Kg of the obtained organic waste is dried and dehydrated in a large oven for dewatering to a moisture content of 50%. The organic waste that has been dewatered is crushed to a size of 5 mm with a pulverizer. The crushed organic waste is placed in an oxygen-limited environment with restricted gas entry, and subjected to microwave heating treatment, and the microwave heating treatment process finally reaches the target temperature of 800°C. When the temperature is below 600°C, the first microwave power is 9KW; when the temperature exceeds 600°C, the second microwave power is 6KW, and before the temperature reaches 900°C, continue to slowly heat up to 900°C. The microwave heating processing equipment is connected to the gas collection device, and the gas is passed through the condensing device to collect the bio-oil; the non-condensable gas is collected to the storage container through the conduit, and the syngas material is obtained.

The method for preparing synthetic gas from organic waste of the present invention has the following effects:

1 The heat efficiency of microwave heating treatment is extremely high, and the production efficiency of synthesis gas is good;

2 The energy consumption of microwave heating treatment is extremely low, and there are no problems such as smoke and odor;

3 The use of microwave heating to treat organic waste, because it can quickly heat up, has a high tolerance for waste volatility, and can avoid the temperature range of 200-400 ℃ caused by dioxin.

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 the scope of the attached patent application.

Claims (10)

A method for generating energy from organic waste, including the following steps: In step (1), an organic waste is subjected to a pre-treatment; In step (2), the pre-treated organic waste is heated to a maximum temperature under a low-oxygen condition. When the temperature is below 600°C, a first heating rate is used, and when the temperature exceeds 600°C When, use a second heating rate; In step (3), the heat-treated organic waste is decomposed into a gaseous substance. Such as claim 1, a method for generating energy from organic waste, wherein the heat treatment in step (2) is to heat the pre-treated organic waste under the oxygen-less condition to a maximum temperature of 800-1000 ℃ between. A method for generating energy from organic waste according to claim 1, wherein the first heating rate in step (2) is greater than the second heating rate. A method for generating energy from organic waste as in claim 1, wherein the first heating rate in step (2) is more than 1.5 times the second heating rate. A method for generating energy from organic waste as in claim 1, wherein the pre-treatment in step (1) is to subject the organic waste to a water removal treatment and a crushing treatment. According to claim 4, a method for generating energy from organic waste, wherein the water removal treatment system is selected from one of mechanical dehydration or dry dehydration, and the moisture content of the organic waste is reduced to 70-50%. Such as claim 4, a method for generating energy from organic waste, wherein the crushing process is to crush the organic waste to less than 10 mm. A method for generating energy from organic waste as in claim 1, wherein the oxygen-reduced condition in step (2) is selected from one of using restricted air intake design or introducing inert gas. A method for generating energy from organic waste as claimed in claim 1, wherein the heating treatment in step (2) adopts microwave heating treatment. Such as claim 8, a method for generating energy from organic waste, wherein when the temperature is below 600°C, a first type of microwave power is used, and when the temperature exceeds 600°C, a second type of microwave power is used, and the first type of microwave power is used. One type of microwave power is greater than the second type of microwave power.

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