RU2492004C1 - Method of town domestic wastes - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to processing of solid domestic wastes. Proposed method comprises collection of wastes in metallic container, loading containers with wastes into the kiln, heating and kilning the wastes by steam-gas heat carrier consisting of hydrocarbon gas combustion products mixed with steam and air at the pressure of steam-gas heat cattier exceeding barometric pressure, discharging container with kilned wastes and emptying them. Amount of steam in heat carrier in kilning is kept within 15%-45%, steam-gas heat carrier temperature makes 500-600°C. Pressure of steam-gas heat cattier exceeds barometric pressure by 20-100 Pa.

EFFECT: fast decontamination in emergent situations.

6 dwg, 1 ex

Description

The invention relates to the field of solid domestic waste processing and can be used in municipal utilities of municipalities for emergency collection and disposal of hazardous organic waste in case of pollution of the city as a result of industrial or natural disasters.

There is a method of complex processing of urban solid household waste, including separate sorting of waste from the residential and non-residential sector of the city, thermal and biothermal treatment of waste sorting products [1].

The disadvantage of this method is the complexity of the operational disposal of hazardous organic waste in emergency situations due to the complexity of the waste processing process, the need for separate waste sorting and the use of expensive equipment.

In addition, there is a known method for processing industrial and household waste and an installation for its implementation, which includes feeding waste to a plant with molten salts and alkalis, consisting of a zone for low-temperature waste treatment with a temperature of from 20 to 550 ° C with a metered supply of water vapor and a high-temperature zone waste processing, which serves water vapor and carbon dioxide [2].

However, this method is characterized by the need to use molten salts, which significantly increases the cost of operational disposal of hazardous organic waste in emergency situations.

There is also known a device for the thermal decomposition of unsorted municipal solid waste, containing a loading device, a gasification chamber, gas burners, a device for forming a mixture of water vapor and light gases, heat exchangers, draft devices and a thermogas outlet pipe to a consumer [3].

A disadvantage of the known installation is the complexity of the operational disposal of hazardous organic waste in emergencies - due to the need for continuous removal of thermogas generated during installation, and the non-use of heat from the combustion of organics.

The closest to the invention in technical essence and the achieved result is a method of thermal processing of household and industrial organic waste, including feeding the waste prepared for processing into the loading chamber, heating the waste with exhaust gases from an internal combustion engine, directing heated waste to a reactor with a temperature of 500-700 ° C, subsequent thermal decomposition of the waste, obtaining liquid and gaseous pyrolysis products and feeding the remainder of the thermal processing waste into the discharge chamber odes [4].

The disadvantage of this known method is the complexity of the operational disposal of hazardous organic waste in emergency situations - due to the need to use an internal combustion engine and the non-use of heat from the combustion of organics directly in the reactor.

The technical result obtained from the invention is the simplification of the operational neutralization of hazardous organic waste in emergency situations.

The technical result is achieved by the fact that in the method of processing municipal household waste, including collecting waste into a metal container, loading the waste container into the furnace, heating and burning the waste with a gas-vapor heat carrier, consisting of products of the combustion of hydrocarbon gas mixed with water vapor and air, under pressure combined-cycle heat carrier in the furnace above atmospheric air pressure, unloading the container with burnt waste from the furnace and pouring out the burnt waste from the container, according to the invention your water vapor in the combined-gas coolant during the firing of waste is maintained within the range of 15% to 45%, the temperature of the combined-gas coolant during the firing of waste is maintained in the range from 500 ° C to 600 ° C, the pressure of the combined gas-heat carrier in the furnace during the firing of waste is maintained above atmospheric pressure air in the range from 20 Pa to 100 Pa.

The author is not aware of technical solutions having features similar to those distinguishing the claimed technical solution from the prototype.

Thanks to the claimed method of processing municipal household waste, it is possible to urgently clean the territory from hazardous organic waste and render it harmless by burning without removal to landfills.

The claimed parameters of the proposed method of processing municipal household waste are based on the results of experimental studies.

It was experimentally established that when firing organic waste at temperatures above 260 ° C, destructive changes in the structure of organic molecules occur, oxidation of the substance by intramolecular oxygen, accompanied by an increase in temperature. It is established that as a result of heating in the presence of air at a temperature above 360 ° C, the substance ignites and burns with a temperature above 700 ° C, accompanied by the formation of soot carbon and the release of soot aerosols into the exhaust flue gases. It was established that in order to prevent the formation of soot carbon, it is necessary to prevent burning of the substance with an increase in temperature above 600 ° C.

The existence of flameless ("smoldering") burning of organic substances with a temperature in the burning area of about 600 ° C was established experimentally. It was also established that the creation of flameless ("smoldering") burning of organics is possible provided that there is water vapor, which is a phlegmatizer that suppresses the development of the combustion temperature, and the presence of oxygen to maintain the combustion process. It was experimentally established that the most efficient way to burn organics is in a gas-vapor coolant with a temperature not exceeding 600 ° C, consisting of the products of the combustion of hydrocarbon gas mixed with water vapor and air. It was found that the maximum lowest temperature of the vapor-gas coolant in the furnace during waste firing is a temperature of 500 ° C, which provides a sufficiently intense oxidation of organic matter.

It was experimentally established that in order to prevent the development of the combustion temperature of organics with ignition and the formation of soot carbon, at least 15% of water vapor should be contained in the steam-gas coolant during waste firing. It was also established that an increase in the volume fraction of water vapor in the composition of a combined-cycle heat carrier during waste firing over 45% increases the cost of preparing water vapor and slows down the waste firing process.

It has been experimentally established that when a waste gas body heats the waste bodies at a pressure higher than the ambient air pressure, heat transfer between the coolant and the bodies accelerates as a result of deeper penetration of the heating gases into the micropores of the bodies. It was found that using an ejector it is possible to create a vapor-gas coolant pressure in the working space of the furnace in excess of atmospheric air pressure above 150 Pa.

It was experimentally established that during the firing of waste bodies in the container under the pressure of a gas-vapor coolant exceeding the pressure of atmospheric air, the effect of accelerated organic oxidation is observed. It has been established that the lowest pressure of the vapor-gas coolant, providing accelerated oxidation of organics during the firing of waste bodies, is a pressure exceeding atmospheric air pressure of 20 Pa. It was also established that with increasing pressure of the vapor-gas coolant in the furnace working space exceeding the atmospheric air pressure over 100 Pa, the complexity of preventing flue gas leaks from the furnace working space through the slots of the sealing equipment into the surrounding atmospheric air significantly increases.

The essence of the invention is illustrated by the scheme.

Figure 1 shows a line for processing municipal waste according to the invention. Figure 2 shows a view of figure 1. Figure 3 shows a view of B in figure 1. Figure 4 shows a view In figure 1. Figure 5 shows a view of G in figure 1. In Fig.6 shows a view of D in Fig.1.

The municipal household waste recycling line contains a container 1, a kiln 2, a rolling platform 3, a burnt waste receiver 4, a conveyor 5, a drive 6, a forklift 7, an electric steel 8. The container 1 is made in the form of a metal box with a trellised bottom, consisting of two opening half-boxes 9 with brackets 10, interconnected by hinges 11 and latches 12. In the normal position of the container 1, the half-boxes 9 are closed, adjoining to each other with the help of latches 12, fixing the closed position of the half-boxes 9.

The kiln 2, connected to the rolling platform 3, is equipped with an ejector (not shown), a burner 13 for burning hydrocarbon gas, a steam pipe 14, an air pipe 15, an exhaust pipe 16 with a throttle 17.

The line for processing municipal household waste works as follows.

Container 1 is installed on the territory of emergency waste collection, filled with collected waste, placed on vehicles and transported to the municipal waste recycling line. Using a forklift 7 remove the container 1 from the vehicle and install it on the rolling platform 3. Roll the platform 3 with the container 1 into the kiln 2 and seal the working space of the furnace. The steam line 14 is opened, the air pipe 15 is opened and the burner 13 is turned on. Natural gas or imported liquefied gas propane is used as the hydrocarbon gas. For the formation of a gas-vapor coolant with a temperature from 500 ° C to 600 ° C, the products of combustion of hydrocarbon gas are mixed using an ejector with water vapor and air.

The container 1 with the waste is heated by blowing the working space of the furnace and the inner space of the container 1 with the gas-vapor heat carrier. When the waste is heated, flameless burning of organics and burning of the waste occurs. The resulting flue gases are removed from the kiln 2 through the exhaust pipe 16. To create a vapor-gas coolant pressure in the working space of the furnace above atmospheric pressure, the exhaust pipe 16 is partially blocked by the throttle 17. The duration of the waste firing is from 6 hours to 24 hours, depending on the characteristics of the waste.

At the end of the waste firing process, turn off the burner 13, stop the flow of water vapor and air, depressurize the working space of the firing furnace 2 and roll out the rolling platform 3 with the container 1 from the firing furnace 2. The container 1 with the burnt waste is removed from the platform 3 with a forklift 7 and transported to the area of action of the electric steel 8 and is installed on the base plate of the receiver 4. The hooks of the slings of the electric steel 8 are hooked by the brackets 10 of the half-boxes 9, the latches 12 are unlocked and the container 1 is lifted by the electric steel 8. When lifting the container 1 by the brackets 10, the half-boxes 9 rotate around the hinge axis 11, the container opens and the burnt waste is poured into the receiver window 4. The opened container 1 is transferred by electric steel 8 for cleaning to prepare for removal from the line, the container 1 is cleaned and lowered to the floor. Unhook the hooks of the slings from the brackets 10 of one of the half-boxes 9 and lift the container 1 from the floor with electric steel 8. When lifting the container 1 by the brackets 10 of one half-box 9, the uncoupled half-box 9 rotates around the hinge axes 11 and the container 1 closes as a result of closing the half-boxes 9. The latches 12 are locked, the container 1 is installed on the floor and the hooks of the electric steel slings are unhooked 8. Container 1 is transported by a forklift 7. for export.

The conveyor 5 is turned on, the calcined waste is transferred from the receiver 4 to the accumulator 6. The calcined waste is dumped from the conveyor 5 into the accumulator 6. The calcined waste is poured into bags and transported to make heat-insulating material from the waste.

An example of the implementation of the proposed method of processing municipal household waste.

In accordance with the proposed method, the processing of hazardous organic waste collected during the cleaning of the territory, containing the corpses of animals mixed with various kinds of objects, was carried out. To collect waste, a metal container with a capacity of 2 cubic meters was used. meters, weighing 160 kg, 2 m long, 1 m wide, 1.2 m high. A waste container with a total mass of 1040 kg was transported to the waste processing line and installed on a platform connected to the kiln. The working space of the furnace was preheated to a temperature of 250 ° C. The platform with the waste container was rolled into the kiln and locked hermetically in the working space of the furnace. Turned on the supply of water vapor to the ejector with a temperature of 110 ° C under an overpressure of 0.11 MPa. An injection burner was turned on to burn liquefied propane gas with an excess of air of 1.4. As a result of adjusting the ratio of the products of combustion of propane gas and water vapor blown into the ejector, a gas-vapor heat carrier was formed with a temperature of 600 ° C, consisting of 59% nitrogen, 29% water vapor, 7% carbon dioxide, 5% oxygen. To create the pressure of the gas-vapor coolant in the working space of the furnace and inside the waste container, the chimney 17 was partially blocked by a choke 17. The pressure of the gas-vapor coolant exceeding the atmospheric air pressure was set to 40 Pa and the position of the choke 17 on the pipe 16 was fixed.

Waste was fired for 12 hours.

At the end of the waste firing process, the burner was turned off, the supply of water vapor to the ejector was stopped, the working space of the furnace was depressurized, and the platform with the container with fired waste from the furnace was rolled out. The container with burnt waste was removed from the platform and mounted on the base plate of the receiver. They opened the container and poured the burnt waste into the receiver.

They turned on the conveyor and poured the burnt waste into the drive. Visually determined that most of the corpses of animals collapsed with the formation of particles ranging in size from 5 mm to 140 mm.

The calcined waste was weighed and determined that the mass of waste after firing decreased by 150 kg and amounted to 630 kg. From the drive, burnt waste was poured into bags each 0.5 × 0.5 × 1.2 m in size with a capacity of 0.15 cubic meters. meters and sent to the manufacture of thermal insulation material.

Using the proposed method for processing municipal household waste in comparison with the known methods makes it possible to simplify the operational disposal of hazardous organic waste without removal to landfills, as well as to obtain raw materials from burnt waste for the production of heat-insulating material.

Information sources

[1] Patent of the Russian Federation for invention No. 2209682 according to application No. 20021231124/03, 08.08.2002 “Method for the integrated processing of municipal solid household waste (MSW)”.

[2] Application for the invention No. 2009137328/03, 09/29/2006 “Method of processing industrial and domestic waste and installation for its implementation”.

[3] Patent of the Russian Federation for invention No. 2433344 according to application No. 201012393/03, March 30, 2010 “Installation for thermal decomposition of unsorted municipal solid waste”.

[4] Patent of the Russian Federation for invention No. 2431778 according to application No.2010111612 / 03, 03.25.2010 “Method for the thermal processing of unsorted municipal solid waste”.

Claims (1)

A method of processing municipal household waste, including collecting waste into a metal container, loading the waste container into the furnace, heating and burning the waste with a gas-vapor heat carrier, consisting of hydrocarbon gas combustion products mixed with water vapor and air, under the pressure of the gas-vapor heat carrier in the furnace above atmospheric pressure air, unloading from the furnace a container with burnt waste and pouring burnt waste from the container, characterized in that the amount of water vapor in the combined-gas the carrier fluid during the firing of waste is maintained in the range from 15% to 45%, the temperature of the combined gas and heat carrier during the firing of waste is maintained in the range of 500 ° C to 600 ° C, the pressure of the combined gas and heat carrier in the furnace during the firing of waste is maintained above atmospheric pressure in the range of 20 Pa up to 100 Pa.

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