RU2640852C1 - Combustion device for crushed wood waste - Google Patents

Abstract

FIELD: power industry.

SUBSTANCE: invention is intended for thermal treatment of crushed wood waste of 3 hazard class, for example, old railway sleepers impregnated with antiseptic agents (coal-containing kreozote impregnating oil), wood chipboards (WCB), fiber boards (FB), waste products of furniture industries, for the purpose of recycling heat, with the content in their combustion products of a low concentration of harmful and carcinogenic substances. In the combustion device for crushed wood waste containing a combustion chamber 1, a burning grate 10, a funnel 5, air nozzles 4, an ash bin 11, a charging branch, according to the invention, the charging branch is executed in the form of a screw with a reverse 7 for transporting the crushed wood waste to the burning grate 10 and attached to the combustion chamber 1, where the air nozzles 4 are arranged in sections. In the lower section with respect to the inner wall 3 of the combustion chamber, the air nozzles 4 made in the form of rectangular tubes that are disposed tangentially, in the middle section, the air nozzles 4 are made in the form of cylindrical tubes that are disposed chordal to the inner wall 3 of the combustion chamber 1, in the upper section the air nozzles 4 are made in the form of cylindrical tubes that are disposed radially along the normal to the inner wall 3 of the combustion chamber 1. The arrangement of the air nozzles relative to the sections of the combustion chamber is arranged in a certain order to provide an intensification of heat and mass transfer throughout the volume of the combustion chamber.

EFFECT: increasing the efficiency of combustion device for crushed wood waste due to increasing intensification of heat and mass transfer, by improving the combustion efficiency of solid fuel in the form of crushed wood waste, which increases operational safety and environmental friendliness.

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Description

The invention relates to a power system and is intended for the thermal neutralization of crushed wood waste of hazard class 3, for example, old railway sleepers, impregnated with antiseptic agents (coal creosote impregnating oil), particle boards (chipboard), wood-fiber boards (MDF), furniture production waste , for the purpose of heat recovery, when the content of their products of combustion is low, the concentration of harmful and carcinogenic substances.

The known "Method and device for burning coal in a vortex stream", where the device comprises a housing, a vortex chamber with tangential slit channels for supplying gas, a nozzle for removing ash deposits, a centrifugal trap for particulate matter, a cyclone, a coal supply unit with a hopper, a burner and a pipe for the exit of combustion products (Patent RU No. 2339874, IPC F23B 70/00, F23C 10/10, publ. 11/27/2008).

Its disadvantages are the need to clean the unburnt coal and ash particles in the cyclone of the exhaust gas, as well as the need to remove heavy ash particles that have settled and accumulated in the vortex chamber branch pipe, leading to reduced intensification and operational safety and environmental pollution during the burning of crushed wood waste (substances are moderately dangerous), leading to a decrease in the efficiency of the device as a whole.

Closest to the technical nature of the claimed technical solution, selected as a prototype, is a "Waste incinerator" containing a combustion chamber with lower and upper working compartments, a casing to which a waste loading pipe and a flue gas exhaust duct are connected, a grate, a diaphragm, a cyclone chamber, devices for removing ash (Patent RU No. 2119123, IPC F23G 5/00, publ. 09/20/1998).

The disadvantages of this technical solution are that the design features of the furnace allow only dry solid waste to be burned, which limits the furnace’s functionality for burning the range of hazardous waste and its quality, as well as the lack of a tedding mechanism, which reduces the intensification and operational safety and environmental pollution when burning crushed wood waste (moderately hazardous substances), leading to a decrease in the efficiency of the furnace as a whole.

The object of the invention is the low efficiency of the device for burning crushed wood waste due to the low intensification of heat and mass transfer, through incomplete combustion of solid fuel, in the form of crushed wood waste of the third hazard class (substances of moderate hazard), which reduces operational safety and environmental friendliness.

The technical result of the claimed invention is to increase the efficiency of the device for burning crushed wood waste by increasing the intensification of heat and mass transfer, by increasing the completeness of combustion of solid fuel in the form of crushed wood waste, which increases operational safety and environmental friendliness.

The technical result is achieved in that in a device for burning crushed wood waste containing a combustion chamber, a grate, a chimney, air nozzles, an ash pan, a loading nozzle, according to which the loading nozzle is made in the form of a screw with a reverse for transporting crushed wood waste to the grate and attached to the combustion chamber, where the air nozzles are located in sections, while on the lower section with respect to the inner wall of the combustion chamber, the air nozzles are made in the form of a rectangular on the middle section, air nozzles are made in the form of cylindrical tubes, which are arranged chordally to the inner wall of the combustion chamber, on the upper section, air nozzles are made in the form of cylindrical tubes, which are arranged radially normal to the inner wall of the combustion chamber, the location of the air nozzles relative to the sections of the combustion chamber is made in a certain order to ensure the intensification of heat and mass transfer throughout the volume of the combustion chamber.

New is:

The proposed device allows you to burn solid wood waste with a low content of harmful substances in the combustion products due to the intensification of heat and mass transfer processes in the combustion chamber, due to the new arrangement of air nozzles in sections relative to the inner wall of the combustion chamber, providing intensive mixing of air throughout the volume of the combustion chamber, wherein the device for burning crushed wood waste does not contain a tedding mechanism, which leads to fire hazard, and the internal NCA combustion chamber does not contain heat-resistant coating, whereby the device for burning the crushed waste wood may be manufactured in a mobile version for burning wood waste in places of their greatest congestion.

To clarify the technical nature of the invention, we consider the drawings:

FIG. 1 - General view of the claimed device;

FIG. 2 - sections aa, bb, bb of the combustion chamber in sections, with the location of the air nozzles in them, where:

- 1 - combustion chamber,

- 2 - outer wall,

- 3 - inner wall,

- 4 - air nozzles,

- 5 - chimney,

- 6 - auger funnel,

- 7 - auger with reverse

- 8 - air pipe,

- 9 - blower,

- 10 - grate,

- 11 - an ash pan.

A device for burning crushed wood waste consists of a combustion chamber 1, a flue gas exhaust duct, which is made in the form of a chimney 5, a blower 9, which is connected to the combustion chamber 1 by means of a nozzle 8. The combustion chamber 1 consists of an inner wall 3 and an outer wall 2, in the space between which the air is pumped by the blower 9. In the lower part of the combustion chamber 1 there is a grate 10, which serves to maintain crushed wood waste. Through the holes in it, the ash residue is poured into the ash pan 11, which is located under the grate 10. The combustion chamber 1 adjoins the nozzle for loading crushed wood waste, which is made in the form of a screw with a reverse 7. Air nozzles 4 in the combustion chamber are arranged in sections: in section AA - upper section; in section BB - the middle section; in section BB - the lower section.

Air nozzles 4 on the lower section with respect to the inner wall 2 of the combustion chamber 1 are located tangentially, in the middle section - chordally, on the upper section - radially.

A device for burning crushed wood waste works as follows.

Using a screw with reverse 7, crushed wood waste is fed to the grate 10, which is ignited by an autonomous ignition device, which is a gas burner with spark ignition. Air is supplied to the combustion chamber 1 from the blower 9 through an air pipe 8, between which a throttle ring is installed, while air is supplied to each section through air nozzles 4 with an inner diameter of 89 mm. With radial and chordal air inlets, air nozzles are made of cylindrical tubes with a diameter of 44.5 mm and a length of three calibers; with a tangential inlet, air nozzles are made of rectangular tubes. When the secondary air was radially supplied, the tubes were located normally to the inner wall of the combustion chamber 1 of the device for burning crushed wood waste, and when the chordal one was at an angle of 26 ... 45 °, while the secondary air was tangentially supplied, the tubes were tangent to the inner wall of the combustion chamber 1. Cross-sectional areas air nozzles 4 and grate 10 are designed so that 30% of the air in the combustion chamber 1 is supplied under the grate 10 through rectangular slots, and the remaining part of the air is uniformly supplied through three sections. Crushed wood waste ignites and begins to decompose. Due to the lack of oxygen in the air, a mixture of gases rich in combustible components is formed over burning crushed wood waste. Secondary air is fed into the gas mixture moving in the direction of the chimney 5 in three sections, which is blown into the combustion chamber 1 by the blower 9. Products that do not have time to burn out burn out in the combustion chamber 1 by supplying secondary air to the afterburning zone. For the vigorous oxidation of decomposition products of crushed wood waste impregnated with toxic substances, air is supplied to the lower and middle sections of the combustion chamber 1 simultaneously in different directions (tangentially and chordally), which ensures efficient mixing of the decomposition products with atmospheric oxygen and their combustion. The supply of air jets into the combustible gas mixture through the air nozzles 4 at different flow angles promotes intensive mixing of gases in the combustion chamber 1, therefore, provides the completeness of combustion of volatile components, which increases the efficiency of the device for burning crushed wood waste. Crushed wood waste in the combustion chamber 1 is fed in a cyclic mode, the mass of the supplied portion per 1 cycle is 5 kg, 10 cycles are carried out within an hour. A layer of burning crushed wood waste forms on the grate 10. The lower part of the layer of burning crushed wood waste is a sublayer of burning coal. The content of volatile components in them is close to zero. The air supplied under the grate 10 is calculated (94 m ³ / h) and makes up 30% of the total air volume (312 m ³ / h), and its amount was sufficient for complete burning of coals. The gaseous products of the combustion of coal, having a temperature of 1100-1200 ° C, heat that part of the crushed wood waste located in the upper part of the layer of burning crushed wood waste. The ash residue under the influence of gravitational forces through the longitudinal slots in the grate 10 falls down into the ash pan 11. No tedding of crushed wood waste on the grate 10 is required, since the coals burn out completely, turning into crumbly ash.

An example of a specific implementation.

Crushed wood waste, for example old railway sleepers, impregnated with antiseptic agents (coal creosote impregnating oil), is loaded into the device for burning crushed wood waste on command from the control panel. Solid crushed wood waste is fed into the combustion chamber 1 by means of a funnel 6 of the screw with a reverse 7 and placed on the grate 10, which are ignited by an autonomous ignition device. Air is supplied to the combustion chamber 1 from the blower 9 through an air pipe 8, between which a throttle ring is installed, while air is supplied to each section through air nozzles 4 with an inner diameter of 89 mm. For radial and chordal air inlets, cylindrical tubes with a diameter of 44.5 mm and a length of three calibers were used, while with a tangential inlet, rectangular tubes were used. When the secondary air was radially supplied, the tubes were located normally to the inner wall of the combustion chamber 1 of the device for burning crushed wood waste, with the chordal tubes, the tubes were located at an angle of 26 ... 45 °, with the tangential one tangential to the inner wall of the combustion chamber 1. The nozzle cross-sectional area 4 and grate 10 are designed so that 30% of the air in the combustion chamber 1 is supplied under the grate 10, and the remaining part of the air is evenly supplied in three sections. Crushed wood waste ignites and begins to decompose. Due to the lack of oxygen in the air, a mixture of gases rich in combustible components is formed over burning crushed wood waste. Secondary air is blown into the gas mixture moving in the direction of the chimney 5 in three sections; it is blown into the combustion chamber 1 by the blower 9. Products that do not have time to burn out burn out in the combustion chamber 1 by supplying additional air to the combustion zone. For the vigorous oxidation of the decomposition products of crushed wood waste impregnated with toxic substances, air is supplied to the lower and middle sections of combustion chamber 1 simultaneously through air nozzles in various directions (tangentially and chordally), which ensures efficient mixing of decay products with atmospheric oxygen and their burning out. The supply of air jets into the combustible gas mixture through air nozzles at different flow angles contributes to intensive mixing of gases in the combustion chamber 1, therefore, provides the completeness of combustion of volatile components, which increases the efficiency of the device for burning crushed wood waste. Crushed wood waste in the combustion chamber 1 is fed in a cyclic mode, the mass of the supplied portion per 1 cycle is 5 kg, 10 cycles are carried out within an hour. A layer of burning crushed wood waste forms on the grate 10. The lower part of the layer of burning crushed wood waste is a sublayer of burning coal. The content of volatile components in them is close to zero. The air supplied under the grate 10 is calculated (94 m ³ / h) and makes up 30% of the total air volume (312 m ³ / h), and its amount was sufficient for complete burning of coals. The gaseous products of the combustion of coal, having a temperature of 1100-1200 ° C, heat that part of the crushed wood waste located in the upper part of the layer of burning crushed wood waste. The ash residue under the influence of gravitational forces through the longitudinal slots in the grate 10 falls down into the ash pan 11. No tedding of crushed wood waste on the grate 10 is required, since the coals burn out completely, turning into crumbly ash. During operation of the device for burning crushed wood waste, the combustion process is monitored. Periodically, through the funnel of the screw 6, crushed wood waste is loaded into the combustion chamber 1. Management of the screw with reverse 7 is carried out in manual or automatic mode. Ash residues are deposited under the grate 10 and fall into the ash pan 11 with subsequent periodic removal from it.

Thus, the advantage of the claimed technical solution in comparison with the known analogues is the increased installation efficiency due to the constructive arrangement of air nozzles and their execution in the form of cylindrical and rectangular tubes located in different directions, providing intensification of heat and mass transfer, as well as increased operational safety and environmental friendliness by increasing the completeness of combustion of solid fuel in the form of crushed wood waste and the absence of a mechanism for tedding coal, when nd it's not zashlakovyvaet grate and does not lead to a sharp rise in temperature, with the result that does not lead to caking coal on the grate, deducing it from the system. And also the implementation of the inner wall of the combustion chamber without a heat-shielding coating provides mobility when moving to the places of greatest accumulation of crushed wood waste, which also increases the efficiency of the device for burning crushed wood waste in general.

Claims (1)

A device for burning crushed wood waste containing a combustion chamber, a grate, a chimney, air nozzles, an ash pan, a loading nozzle, characterized in that the loading nozzle is made in the form of a screw with a reverse for transporting crushed wood waste to the grate and attached to the combustion chamber where the air nozzles are located in sections, while on the lower section with respect to the inner wall of the combustion chamber, the air nozzles are made in the form of rectangular tubes, which are tangent Specifically, in the middle section, the air nozzles are made in the form of cylindrical tubes, which are arranged chordally to the inner wall of the combustion chamber, on the upper section, the air nozzles are made in the form of cylindrical tubes, which are arranged radially normal to the inner wall of the combustion chamber, and the arrangement of the air nozzles relative to the sections the combustion chamber is made in a certain order to ensure the intensification of heat and mass transfer throughout the volume of the combustion chamber.

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