RU2767786C1 - Method and device for pyrolysis of municipal and other waste - Google Patents

Abstract

FIELD: waste treatment.

SUBSTANCE: group of inventions relates to the processing of municipal solid and other organic waste, including contaminated recyclable materials, biomaterials, and, in particular, can be used in the field of disposal of hazardous and especially hazardous organic and inorganic waste using microwave energy. The method for pyrolysis of waste consists in the fact that fragmented waste in fractions up to a diameter of 5-20 mm is injected from the tank into the feeder. Then the waste is periodically introduced into the reactor process chamber, in which the material is heated from the hot walls of the reactor and using microwave energy emitted in the reactor chamber by microwave emitters. In this case, the material is additionally heated to a temperature from 600 to 900°C, and the gases formed as a result of thermal decomposition enter a two-section separator. Heavy hydrocarbon fractions and deposited soot are removed and returned to the rector’s process chamber using a conveyor belt, and the remaining purified gases are sent to the electric generator engine or compressed in containers.

EFFECT: complete disposal of solid municipal and other organic waste, including contaminated recyclable materials, biomaterials.

5 cl, 5 dwg, 4 ex

Description

The invention relates to the field of processing solid municipal and other organic waste, including contaminated recyclable materials, biomaterials, and, in particular, can be used in the field of disposal of hazardous and highly hazardous organic and inorganic waste using microwave energy. The invention can be used in the field of disposal of hazardous and highly hazardous organic and inorganic waste, and can also be used in the field of transport, including road, water and rail transport.

The problem of waste disposal and recycling of solid municipal and other organic waste, including contaminated recyclable materials, biomaterials, has existed for a long time and has already become increasingly important due to the ever-increasing amount of waste, both industrial and from other sources.

State of the art

One of the ways to dispose of household (communal) waste, plastics, tires and biological waste is pyrolysis / gasification. This process produces gases such as hydrogen, carbon monoxide and hydrocarbons, which can then be burned or fed into internal combustion engines coupled to power generators. This competitive solution is used for waste incineration in large incinerators.

There are many technical solutions for waste gasification.

Known technical solutions for pyrolysis/gasification plants are based on co-combustion processes, in which the reactor partially burns gasified waste and heats the material using the energy obtained from combustion, or the material is heated by contact method due to the thermal conductivity of the reactor walls. Such methods of heating gasified material have a number of disadvantages. For example, co-combustion usually uses a gas with a composition containing a large amount of carbon dioxide, and therefore the composition of this gas does not allow to increase the supply of internal combustion engines. Therefore, the gases obtained in this way are often mixed with pure natural gas in order to enrich the mixture and obtain better energy parameters.

Known contact method of heating based on the thermal conductivity of the walls of the reactor is characterized by the effect of creating layers of fine coke and slag on the inner surface of the reactor, which reduces the thermal conductivity of the walls and slows down the speed of the heating process. In addition, in this process, the energy efficiency of heating the gasified material is low.

A known method of heating the material in the reactor using microwave energy (international application WO2014184290A1, as well as European patent EP2997110). In this method, the material is mixed inside a ceramic drum and heated by microwave radiation from one or more microwave generators. This method makes it possible to obtain a pyrolytic gas of a better composition. However, the disadvantage of this method is that, along with the gas from the reactor, heavy hydrocarbon fractions and soot also enter the gas cooling system, which leads to rapid contamination of pipes and filters. Another important technical problem in this solution is the need to use a drum made of ceramic, the size of which and the possibility of cracking ceramics limit the productivity of the process.

When using the method of pyrolysis and gasification of waste, high-energy gases are formed, containing such combustible gases as hydrogen, methane, carbon monoxide, as well as complex hydrocarbons, which, after cooling, turn into tarry substances, and soot is deposited. These substances must be separated from combustible gases (and from liquid hydrocarbon fractions formed during pyrolysis). As a rule, special filter systems using thermal cracking and plasma systems are used for this. The disadvantage of the filter system is their rapid clogging with absorbed substances and, as a result, the need for frequent replacement of filters. In addition, used filters contain harmful substances and must be disposed of as hazardous waste.

Filtration methods, membrane methods and pressure swing adsorption are used to separate hydrogen, methane, ethane, propane, butane and other gases used as valuable energy sources. Filtration is the oldest method, but it has a big drawback: the filters are consumed very quickly and are difficult to dispose of by-products. In addition, the efficiency of the filters during operation is reduced due to clogging with dust and heavy hydrocarbon fractions and tarry substances.

The pressure swing adsorption method, which is often used today, is characterized by a relatively high efficiency. However, this method is expensive and complicated when operating equipment in industrial conditions. In addition, the heavy ends adsorbed on the active beds are difficult to remove during the purification phase of the column. This method is also very sensitive to water vapor present in the gasification off-gases.

Another method currently tested is the high selectivity membrane separation method. Proper selection of the membrane ensures very high efficiency (higher than for filters). Membranes, like filters, wear out and are a hazardous by-product requiring further special disposal. The presence of sulfur compounds or volatile amines, which, after the gasification process, enter the flue gas stream in large quantities, causes aging of the membranes, which lose their effectiveness. For the reasons outlined above, membrane methods are of limited use in industrial settings.

In turn, thermal cracking methods require heating gases containing tarry substances to decompose complex hydrocarbon substances into simple compounds such as methane, ethane, propane, carbon monoxide, etc. One of the well-known methods of such thermal cracking is the plasma method, in which complex hydrocarbon substances are decomposed in a gas plasma at very high temperatures. Thermal methods, including plasma, require large amounts of energy and the construction of special expensive installations. The efficiency of tar gas purification is also limited due to DE NOVO reactions (cooling the gas mixture causes unfavorable chemical reactions and, as a result, harmful substances are synthesized again on their own).

Disclosure of the essence of the invention

The objective of the present invention is the complete disposal of solid municipal and other organic waste, including contaminated recyclable materials, biomaterials.

The problem is solved due to the method of pyrolysis of household, organic and especially hazardous organic and inorganic waste. When implementing the method, fragmented waste in fractions up to a diameter of 5 - 20 mm from the tank is introduced into the feeder (1). Then, it is periodically introduced into the process chamber of the reactor (2), in which the material is heated from the hot walls of the reactor (2) and with the help of microwave energy emitted in the reactor chamber (5) by microwave emitters (6). In this case, the material is additionally heated to a temperature from 600°C to 900°C, and the gases formed as a result of thermal decomposition enter the two-section separator (4), heavy hydrocarbon fractions and precipitated soot are removed and returned to the process chamber (5) of the reactor (2) using a belt conveyor (9), and the remaining purified gases are sent to the engine (13) of the electric generator (14) or compressed in containers.

In accordance with a particular case of the implementation of the method, the walls of the separator (4) are cooled in two sections. Moreover, in the first section (10) cooling is carried out by air flow, using a fan, and in the second section (11) by water cooled by a closed circulation heat exchanger.

In addition, the problem is solved due to the fact that the device for the pyrolysis of household, organic and highly hazardous organic and inorganic waste includes a container, a dispenser, a process chamber, a feeder (1), a reactor (2), microwave emitters (6) connected to Microwave generators with a power of 3 kW each, with a frequency of 2.45 GHz, as well as / or microwave generators with a frequency in the range from 900 MHz to 4000 MHz, as well as a cyclone or multicyclone (15), a scrubber (12) and a motor (13) connected to an electric generator (14). The reactor (2) includes a chamber (5) with thermal insulation and built-in microwave emitters (6) on the walls, connected to microwave generators and with a stirrer (7), which is placed inside the chamber (5) of the reactor (2), separator (4) with walls cooled in two sections (10;11), a pipe (8) located in the upper part of the chamber (5) of the reactor (2), two or more belt conveyors (9).

In accordance with special cases of the device, the agitator (7) has the shape of a rotating cone. In addition, the rotating cone is made of heat-resistant steel, preferably with built-in silicon carbide (SiC) elements.

Brief description of drawings:

Fig. 1: Block diagram of the system;

Fig. 2: Diagram of the device;

Fig. 3: Scheme of the device according to example 1;

Fig. 4: Diagram of the device according to example 2;

Fig. 5: Diagram of the device according to example 4.

Designation in the figures : feeder (1), reactor (2), microwave heater system (3), separator (4), reactor chamber (5), microwave emitters (6), agitator (7), separator tube (8) , belt conveyor (9), air-cooled separator section (10), water-cooled separator section (11), scrubber (12), motor (13), electric generator (14), cyclone/multicyclone (15).

The technical result consists in the fact that municipal waste, medical waste, plastic waste, other waste at the first stage is crushed to a fraction of Ø5-20 mm, dried and preheated with gases coming from the heat exchanger. Then the waste is introduced through the dispenser using a special conveyor into the working chamber. The dosing system, preferably a honeycomb dosing system or a pulsed material injection piston conveyor system, compresses the material portions to prevent too much air from entering the process chamber along with the gasified material. This material inside the process chamber of the reactor is preheated using the walls of the reactor and additionally heated inside the second process chamber using microwave energy to a temperature in the range of 600-900°C, at the same time the material is slowly moved through the reactor chamber using a belt conveyor or a vibrating conveyor using pushers. rods.

At the end of the first process chamber, in its lower part, there is an opening through which the solid fractions remaining after gasification are poured into a container located outside the reactor, the size (volume), which is usually about 0.2 - 1 m3.

The material (solid fractions - carbonizate) is removed into insulated containers (without air or containers filled with nitrogen). Hot gases from the second process chamber are returned to the first section of the chamber of the separation device (separator, in which the subsequent condensation of heavy hydrocarbon fractions on the cooled walls occurs. In the first section, usually located in the upper part of the separator chamber, the walls are made of ceramic, which conducts heat well ( silicon carbide) or heat-resistant steel, and are cooled by a cold air flow from a fan. The gases are then directed to a second section with water-cooled walls. cooled, which allows to reduce its temperature to about 40-50 ° C.

Liquid hydrocarbon fractions and soot are deposited during cooling on the walls of the separator and are transferred back to the process chamber using a two- or three-lane conveyor. These fractions are re-introduced into the high temperature zone, heated by microwave energy to a high temperature in the range of 600-900 ° C, which leads to further decomposition of complex hydrocarbons into simple hydrocarbons, hydrogen, carbon monoxide and carbonizate.

The gases from the separator chamber, purified from heavy hydrocarbon fractions, are sent to a cyclone or multicyclone, which captures the dust carried in the gas stream. Then the gases, previously treated in a cyclone or multicyclone, are sent to containers in which shelves are placed with layers of quicklime and activated carbon to absorb sulfur, chlorine and fluorine. Then, the thus purified gas is burned in the burner of the steam generator, in the heater, or they enter the internal combustion engine connected to the electric generator.

Microwave emitters emit electromagnetic waves, type E01 (TM01) and/or E02 (TM02), and adjacent emitters emit polarized electromagnetic waves with mutually perpendicular polarities.

To implement this method, a device (figure 1) is used, including a container and a dispenser in which the recyclable material is placed, the feeder (1) which is made in the form of an elongated sleeve with a piston, the reactor (2), which consists of a chamber (5) with thermal insulation and microwave emitters (6) built into the walls of the chamber, connected to microwave generators with a power of 3 kW each, with a frequency of 2.45 GHz, as well as / or microwave generators with a frequency in the range from 900 MHz to 4000 MHz, and with a stirrer (7) located in the reactor chamber (5), to remove pyrolytic gases through a pipe (8) located in the upper part of the chamber (5) of the reactor (2), the gases enter the separator (4) with walls cooled in two sections (10;11): in the first section (10) with cold air, and in the second section (11) with water, using two or more belt conveyors (9) inside the pipe (8), transporting substances deposited on the inner walls of the pipe (8 ), with return back inside the chamber (5) of the reactor (2). Gases, purified from heavy hydrocarbon fractions and sludge, are sent through a cyclone (or multicyclone) (15) to a scrubber (12), and after removing chlorine, fluorine and sulfur, the gases are introduced into an engine (13) connected to an electric generator (14). Microwave emitters (6) emit electromagnetic waves, type E01 (TM01) and/or E02 (TM02), and adjacent emitters emit polarized electromagnetic waves with mutually perpendicular polarities.

1 exemplary implementation of the method according to the invention:

The material to be disposed of from the dispenser tank is fed into the feeder (1). The material from the feeder (1) is fed into the reactor (2), in which it is heated by microwave energy emitted by tubular radiators (3) connected to microwave generators with a power of 3 kW each, with a frequency of 2.45 GHz. The material to be disposed of is heated in the second chamber to a temperature in the range from 600 to 900 °C. As a result of heating in an atmosphere without oxygen, or with a large lack of oxygen, the material is decomposed and gasified. The gases removed from the reactor chamber (5) are sucked into the separator (4), which includes two sections (10;11) with walls cooled by cold air and water (figure 2).

On the cold walls of the separator (4), which has sections (10;11), resinous fractions and soot condense from gases, which, then, using a double belt conveyor (9), are returned to the second chamber (2), in which, due to high temperature, they decompose into simple hydrocarbons, carbon monoxide and hydrogen (figure 2). The gases previously cleaned in the separator (4) from resinous substances and soot are sent to the purification system (12), in which chlorine, fluorine and sulfur are absorbed. For this purpose, the so-called scrubber (12) is used - a device in which chlorine, fluorine and sulfur are absorbed by calcium compounds. The purified gases are introduced into an internal combustion engine (13) (eg, a gasoline engine) driving an electric generator (14).

Solid fractions (carbonizate) are discharged from the chamber (5) of the reactor (2) and they enter the tank (tank for solids).

For example, by introducing plastic waste, crushed into particles up to 3-5 cm in size, into the tank, and introducing this waste into the first chamber, and using 16 microwave generators with a power of 3 kW each, a temperature of about 900 ° C can be reached in the reactor (2). C. With a recycling capacity of about 300 kg of waste per hour, high-energy gases are produced from such waste, which, after processing, make it possible to obtain up to 350-400 kW of electricity.

2 exemplary implementation of the method according to the invention:

The device (Fig. 3) consists of a chamber (5) in which microwave emitters (6) are embedded. The crushed recyclable material is introduced into the reactor chamber (5) and moved using pushers. Pyrolysis gases are released when the material is heated by microwave waves in the frequency range from 900 MHz to 4000 MHz inside the chamber (5) at a temperature in the range of 650 - 900 °C, they are sucked into the separator pipe (8), inside which the belt conveyor (9) is located. Two cooling sections are mounted on the pipe (8): a section (10) cooled by cold air and a section (11) cooled by cold water. As a result of pipe (8) cooling, heavy hydrocarbon fractions and soot settle on its surface and are returned to the chamber (5) by means of a belt conveyor (9). Heavy hydrocarbons introduced into the chamber (5) and soot heated to a high temperature are further decomposed and gasified. Pyrolysis gases after condensation (separation) of heavy hydrocarbons through the pipe (8) are introduced into the separator, then transferred to the cyclone (15), and then to the chlorine, fluorine, sulfur purification system of the scrubber (12).

3 exemplary implementation of the method according to the invention:

Crushed recyclable material (municipal or other waste) is introduced into the reactor chamber (5), where microwave emitters (6) are installed (figure 4). This material is heated using microwave energy to a temperature of about 650-900 °C, decomposed and gasified. The material to be disposed of is moved inside the reactor chamber (5) by means of a stirrer (7). Pyrolysis gases are sucked into the separator pipe (8), inside which a belt conveyor (9) is placed. Pipe (8) is cooled in section (10) with cold air and in section (11) with water. As a result of cooling the surface of the pipe (8), heavy hydrocarbons and soot accumulate on its inner surface and are returned to the chamber (5) by means of a belt conveyor (9), where, as a result of heating to a high temperature, they decompose and gasify. Purified from heavy hydrocarbons and soot, pyrolysis gases are sent to the engine (13) with an electric generator (14).

4 exemplary implementation of the method according to the invention:

The crushed recyclable material is introduced into the reactor chamber (5), on which microwave emitters (6) are installed, and inside the reactor chamber (5), as a result of heating to a temperature in the range of 650–900 °C, the material is decomposed and gasified. The material to be disposed of is moved inside the chamber (5) by means of a stirrer (7) having the shape of a rotating cone (FIG. 5). The pyrolysis gases released during the heating process are sucked into the separator pipe (8), inside which a belt conveyor (9) is located. Pipe (8) is cooled in section (10) with cold air, and in section (11) with water. As a result of cooling the surface of the pipe (8), heavy hydrocarbons and soot accumulate on its inner surface and return to the reactor chamber (5) using a belt conveyor (9), where, as a result of heating to a high temperature, they decompose and gasify. Purified pyrolysis gases are sent to the engine (13).

In examples 2, 3, 4, the gas purification system from chlorine, sulfur and fluorine is produced as described in example 1, as well as the engine (13) and electric generator (14), as in example 1.

Claims (5)

1. A method for the pyrolysis of household, organic and especially hazardous organic and inorganic waste, in which fragmented waste in fractions up to a diameter of 5-20 mm is introduced from the tank into the feeder (1), then periodically introduced into the process chamber of the reactor (2), in which the material is heated from the hot walls of the reactor (2) and with the help of microwave energy emitted in the reactor chamber (5) by microwave emitters (6), characterized in that the material is additionally heated to a temperature of 600 to 900°C, and the resulting thermal decomposition gases enter the two-section separator (4), heavy hydrocarbon fractions and deposited soot are removed and returned to the process chamber (5) of the reactor (2) using a belt conveyor (9), and the remaining purified gases are sent to the engine (13) of the electric generator ( 14) or compressed in containers. 2. The method according to claim 1, characterized in that the walls of the separator (4) are cooled in two sections, and in the first section (10) cooling is carried out by air flow using a fan, and in the second section (11) by water cooled by a heat exchanger with a closed circulation. 3. A device for the pyrolysis of household, organic and highly hazardous organic and inorganic waste, including a container, a dispenser, a process chamber, a feeder (1), a reactor (2), microwave emitters (6) connected to microwave generators with a power of 3 kW each , with a frequency of 2.45 GHz, and / or microwave generators with a frequency in the range from 900 to 4000 MHz, as well as a cyclone or multicyclone (15), a scrubber (12) and a motor (13) connected to an electric generator (14) , characterized in that the reactor (2) includes a chamber (5) with thermal insulation and built-in microwave emitters (6) on the walls, connected to microwave generators and with a stirrer (7), which is placed inside the chamber (5) of the reactor (2) , a separator (4) with walls cooled in two sections (10;11), a pipe (8) located in the upper part of the chamber (5) of the reactor (2), two or more belt conveyors (9). 4. Device according to claim 3, characterized in that the agitator (7) has the shape of a rotating cone. 5. The device according to claim 4, characterized in that the rotating cone is made of heat-resistant steel, preferably with built-in silicon carbide (SiC) elements.

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