RU2638500C1 - Method for incineration of milled solid fuel and device for its implementation - Google Patents

Abstract

FIELD: power industry.

SUBSTANCE: device for incineration of milled solid fuel consists of two stages, the first stage is made in the form of gas generator and the second stage is in the form of post-combustion chamber, the gasification unit of fine fraction contains co-axially primary countercurrent and secondary countercurrent flame tubes, a turbulence chamber interposed between them, containing flame tube whose diameter is larger than the diameters of the primary countercurrent and secondary countercurrent flame tubes, each primary countercurrent and secondary countercurrent flame tubes contain tangential nozzle swirlers that form a twist of flows with the opposite direction of the angular velocity vectors, wherein the primary countercurrent flame tube in the plane of tangential nozzle swirler contains a nozzle coaxial to its central axis, the second stage comprises a cylindrical body, a flame tube, tangential nozzle swirler, outlet nozzle with a central inlet, located in the plane of the tangential nozzle swirler, and an outlet, a pre-chamber with inlets and outlets, wherein the tangential nozzle swirler forms flow twist that coincides with the direction of flow twist angular velocity in the primary countercurrent flame tube, the nozzles of air supply, removal of mixture of solid particles and gas, wherein the air supply nozzle communicates with the tangential nozzle swirler, and the nozzle for removal of mixture communicates with the flow part of flame tube in opposite to the tangential nozzle swirler end. The nozzles are installed tangentially on the inner surface of casing so that the angular velocity vectors of the air flow and the flow of mixture of solid particles and gas coincide in direction with the angular velocity vector of air at the outlet of nozzle swirler.

EFFECT: increase the efficiency of work process of fuel combustion by increasing productivity, economic and environmental characteristics, expanding the type of fuel burned and increasing the reliability of work process.

2 cl, 6 dwg

Description

The invention relates to the field of power engineering, and in particular to a method for burning coal, carbon-containing waste products from various industries and other types of solid fuel.

A known method of burning coal dust in a swirl chamber (RF patent No. 2418237; class F23C 5/24, F23K 1/00; published January 19, 2009) by burning fuel in the combustion zone between two strongly swirling streams.

A known method of burning ground solid fuel (RF patent No. 2258866; class F23C 10/00, F23C 1/12; published on 08/20/2005), selected as a prototype, by gasification in the first stage and afterburning in the second stage, while in the first the stages create a swirling flow of crushed fuel with an excess air coefficient of less than unity, and large particles are directed into a fluidized bed for their final gasification, afterburning and separation of ash particles from the gaseous product stream.

The disadvantages of the known methods are:

1) low productivity due to slow heat and mass transfer due to insufficient flow turbulence, insufficiently efficient mixture formation, fuel supply and formation of the air-fuel mixture require time-consuming;

2) low economic characteristics due to low productivity;

3) low environmental characteristics, high residence time of combustion products in the zone of high temperatures, which contributes to the synthesis of nitrogen oxides;

4) limited use of types of combustible fuels due to the low level of turbulization;

5) low reliability of the working process due to high thermal loads on the walls of the gas generator.

The above disadvantages lead to a decrease in the efficiency of the working process of burning fuel.

A device for burning coal dust in a swirl chamber is known (RF patent No. 2418237; class F23C 5/24, F23K 1/00; published July 27, 2010), containing a cylindrical vortex combustion chamber made of two swirling devices with opposite swirling directions, offset from each other relative to each other in the axial direction.

A device for burning ground solid fuel is known (RF patent No. 2258866; class F23C 10/00, 1/12; published August 20, 2005), selected as a prototype, consisting of two stages, the first stage is made in the form of a gas generator, and the second stage is made in the form of a afterburner.

The disadvantages of the known devices include:

1) low productivity of fuel combustion due to inefficient turbulization of flows;

2) low economic characteristics;

3) low environmental characteristics due to the complexity of implementation, large dimensions;

4) limited use of types of combustible fuel;

5) low reliability due to high thermal loads on the walls of the gas generator.

The technical result achieved in the claimed invention is the creation of a method and device for its implementation, which allows to increase the efficiency of the working process of burning fuel by increasing productivity, economic and environmental characteristics, expanding the type of fuel burned and increasing the reliability of the working process.

The technical result in the claimed method is achieved by gasification in the first stage and afterburning in the second stage, while in the first stage a swirling stream of crushed fuel is created with an excess air coefficient of less than unity, and large particles are directed into a fluidized bed for their final gasification, afterburning and separation ash particles from the flow of gaseous products.

New in the method is that in the first stage an intense turbulent zone is created for crushed fuel with air by the formation of two strongly swirling flows that are countercurrent in peripheral speed, while each swirling stream generates external and internal flows moving in countercurrent with axial velocities in relation to external flows, the second stage is made in the form of a afterburner, where external and internal flows are formed, moving in countercurrent with axial velocities, and the combustion zone is formed in internal flow, a mixture of non-combustible components is discharged through the corresponding pipe.

The formation of air flows in the fine fraction gasification unit is carried out in the form of two strongly swirling countercurrent and direct-flow streams containing each of the external and internal flows. This leads to an increase in the productivity of the working process due to the formation of flow patterns with highly developed anisotropic turbulence that prevails in the radial direction in a field with a high radial gradient of static pressure, which increase the processes of mixture formation and combustion by increasing heat and mass transfer processes, and also increase the reliability of the combustion process by its stabilization by burning turbulent moles moving radially, and the stabilization of the working process is achieved Uteem stabilize the turbulent burning moles, moving radially into the combustion zone from the separation zone of the external and internal threads.

Countercurrent and direct-flow flows are formed with opposite directional vectors of peripheral velocities, and internal flows are formed with vectors of the axial velocity component coinciding with the velocity vector of the internal flow of a countercurrent strongly swirling flow. A turbulization zone is formed in the interface zone of the countercurrent and direct-flow flows, in which the external flows are radially expanded, with intensification of the turbulence of the flow, an increase in the radial velocities at the entrance to this zone, and a decrease in the radial velocity of the radial flow formed from them. This leads to an increase in the productivity of the working process due to increased turbulence of flows, which leads to an intensification of the processes of mixture formation and combustion, as well as to an increase in the reliability of the combustion process, by its stabilization by the formed radial flows.

A mixture of crushed fuel with air is formed, which is accelerated and fed into the highly twisted external countercurrent and direct-flow flows. The air-fuel mixture is ignited from an external source with the formation of combustion and gasification zones in the internal flows and in the zone of turbulization of the flows of the first stage. This leads to an increase in the reliability of the design and the combustion process, achieved by forming an air curtain by external flows, removing the thermal load of the walls of the flame tubes, and the formation of combustion and gasification zones in internal flows, and the stabilization of the working process is achieved by its stabilization by burning turbulent moles, moving radially into the combustion zone from the zone of separation of external and internal flows.

Afterburning of the obtained gas in the second stage is carried out by forming a strongly swirling air stream consisting of external and internal flows moving with opposite axial velocity components, into the internal stream of which the internal total stream of gasification products of the first stage is ejected. The organization of ejection of gasification products leads to an increase in the productivity of the working process due to an increase in shear axial velocities at the interface between external and internal flows, as well as to an increase in economic characteristics by reducing the power load on external air supply devices to the first stage.

Behind the tangential nozzle swirling apparatuses of the first and second stages in the direction of the axial velocity of the external flows, shear diffuse flows are formed along the axial velocity component with the formation of toroidal vortices, which increases the reliability of the combustion process by stabilizing it by forming local combustion zones that stabilize the combustion process as in the turbulization zone, and in the combustion zone of internal flows.

An additional supply of gaseous, liquid or crushed solid fuel, as well as mixtures of various fuels, is carried out in the turbulization zone. This leads to an increase in the productivity of the working process, and also expands the use of this method by the type of fuel burned.

Radial air jets are introduced from the external stream of the second stage into the stream of gasification products of the first stage, which enters the second stage for afterburning, which increases the reliability of the combustion process in the second stage by stabilizing it by forming local combustion zones behind the radial jets.

In an external highly swirling flow of the second stage, non-combustible components are separated, which are removed from the second stage in the zone of variation of the axial component of the external flow velocity vector. This leads to an increase in the environmental characteristics of the method due to the absence of emissions from flue gases of solid non-combustible particles into the atmosphere.

In a direct-flow strongly swirling flow, a part of the external flow is formed with an increase in the peripheral velocity component in the direction opposite to the axial velocity component, in which the solid non-combustible components of solid fuel are separated, followed by their continuous withdrawal from the direct-flow strongly swirling flow. This leads to increased economic and environmental characteristics of the method due to the implementation of a long continuous working process and the absence of emissions of solid non-combustible particles into the atmosphere with flue gases.

In the external stream from the output side of the separated solid components, including unburned fuel, hot air is supplied, heated by the supplied heat removed from the non-combustible components to be removed. This leads to an increase in the productivity of the method due to an increase in the rate of chemical reactions and an increase in the economic characteristics of an increase in the completeness of fuel combustion.

The technical result in the claimed device is achieved in that the device for burning crushed solid fuel consists of two stages, the first stage is made in the form of a gas generator, and the second stage is made in the form of an afterburner.

New in the device is that the fine fraction gasification unit contains coaxial primary countercurrent and secondary countercurrent flame tubes, a turbulization chamber located between them, containing a flame tube whose diameter is larger than the diameters of the primary countercurrent and secondary countercurrent flame tubes, each primary countercurrent and secondary countercurrent flame tubes contain tangential nozzle swirling apparatuses, forming a swirl of flows with the opposite direction of the angular vectors speed, while the primary countercurrent heat pipe in the plane of the tangential nozzle swirling apparatus contains a pipe coaxial to its central axis, the second stage contains a cylindrical body, heat pipe, tangential nozzle swirling device, the outlet pipe with a central inlet located in the plane of the tangential nozzle swirling device , and an outlet, a pre-chamber with inlet and outlet openings, while a tangential nozzle swirling apparatus forming spins the flow swirl, which coincides with the direction of the angular velocity vector of the swirl flow in the primary countercurrent flame tube, the air supply pipe, the discharge of the mixture of residual solid particles and gas, and the air supply pipe communicates with the tangential nozzle swirling device, and the pipe of the mixture discharge communicates with the flow part of the heat pipes at the end opposite from the tangential nozzle swirling apparatus, while the nozzles are installed tangentially on the inner surface of the housing so that the angles The output air velocity and the mixture flow of residual solid particles and gas coincide in direction with the angular velocity vector of the air at the outlet of the nozzle swirling apparatus.

Using the design of the device for crushed solid fuel allows to increase the efficiency of the combustion process due to the fine fraction gasification unit containing coaxial primary countercurrent and secondary countercurrent flame tubes and a turbulization chamber located between them, which allows to increase the turbulization process.

The invention is illustrated by drawings, where

in FIG. 1 is a longitudinal section of a device;

in FIG. 2 is a longitudinal section aa;

in FIG. 3 - section BB;

in FIG. 4 - section bb;

in FIG. 5 - section GG;

in FIG. 6 - section DD.

The device for burning crushed solid fuel consists of two stages. The first stage is made in the form of a gas generator, and the second stage is made in the form of a afterburner.

The first stage contains coaxially placed primary countercurrent 1 (Fig. 1, 2) and secondary countercurrent 2 (Fig. 1, 2) flame tubes and a turbulization chamber 3 placed between them (Fig. 1, 2, 3).

The turbulization chamber 3 (Fig. 1, 2, 3) contains a flame tube 4 (Fig. 1, 2, 4), the diameter of which is greater than the diameters of the primary countercurrent 1 (Fig. 1, 2) and the secondary countercurrent 2 (Fig. 1, 2 ) flame tubes. Each primary countercurrent 1 (Fig. 1, 2) and secondary countercurrent 2 (Fig. 1, 2) flame tubes contain tangential nozzle swirling devices 5 (Fig. 1, 2, 5) and 6 (Fig. 1, 2, 4) forming a swirl of flows with the opposite direction of the angular velocity vectors.

The primary countercurrent 1 (Fig. 1, 2) flame tube in the plane of the tangential nozzle swirling apparatus 5 (Fig. 1, 2, 5) contains a pipe 7 (Fig. 1, 2), coaxial to its central axis.

The second stage contains a cylindrical body 8 (Fig. 1, 2), a flame tube 9 (Fig. 1, 2), a tangential nozzle twisting apparatus 10 (Fig. 2), an outlet pipe 11 (Fig. 1, 2) with a central inlet 12 (Fig. 1, 2), located in the plane of the tangential nozzle swirling apparatus 10 (Fig. 2), and an outlet 13 (Fig. 2), a chamber 14 (Fig. 1, 2) with inlet and outlet openings 15 (Fig. . 1, 2), 16 (Fig. 1, 2), air supply nozzles 17 (Fig. 2), discharge mixture 18 (Fig. 1, 5) of the remains of solid particles and gas.

The air supply pipe 17 (Fig. 2) communicates with the tangential nozzle swirling apparatus 10 (Fig. 2), and the pipe of the mixture outlet 18 (Fig. 1, 5) communicates with the flow part of the flame tube 9 (Fig. 1, 2) in the opposite from the tangential nozzle swirling apparatus 10 (Fig. 2) end.

The nozzles 17 (Fig. 2), 18 (Fig. 1, 5) are installed tangentially to the inner surface of the housing 8 (Fig. 1, 2) so that the angular velocity vectors of the air flow and the mixture flow of the residues of solid particles and gas coincide with vector of angular velocity of air at the outlet of the nozzle swirling apparatus 10 (Fig. 2).

In this case, the tangential nozzle swirling apparatus 10 (Fig. 2) generates a flow swirl that coincides with the direction of the angular velocity vector of the swirl flow in the primary countercurrent 1 (Fig. 1, 2) flame tube.

A method of burning ground solid fuel.

To the gas generator from external sources through the nozzles 19 (Fig. 1) and 20 (Fig. 1), air is supplied to the primary countercurrent 1 (Fig. 1, 2) and the secondary countercurrent 2 (Fig. 1, 2) heat pipes, through nozzle twisting devices 5 (Fig. 1, 2, 5) and 6 (Fig. 1, 2, 4).

In each flame tube 1 (Fig. 1, 2) and 2 (Fig. 1, 2), an external strongly swirling flow is formed, which is countercurrent at a peripheral speed, and generating internal flows moving in countercurrent with axial velocities with respect to external flows . Then the external flows enter the flame tube 4 (Fig. 1, 2, 4) of the turbulization chamber 3 (Fig. 1, 2, 3).

The crushed fuel is fed through the feed device 21 (FIG. 5) to the nozzle swirling apparatus 5 (FIG. 1, 2, 5) of the flame tube 1 (FIG. 1, 2) and through the device 22 (FIG. 4) to the nozzle swirling device 6 (Fig. 1, 2, 4) of the flame tube 2 (Fig. 1, 2).

At the same time, air is supplied to devices 21 (Fig. 5), 22 (Fig. 4) to form a fuel-air mixture, which enters the formed external flows of flame tubes 1 (Fig. 1, 2) and 2 (Fig. 1, 2).

Carry out the ignition of the air-fuel mixture in the turbulization chamber 3 (Fig. 1, 2, 3) by ignition devices 23 (Fig. 3), 24 (Fig. 3), which form the combustion and gasification zone in the internal flows of the flame tubes 1 (Fig. 1, 2), 2 (Fig. 1, 2), 4 (Fig. 1, 2, 4).

The gasification products of the first stage are moved by the internal flow in the direction of the second stage and enter through the inlet 15 (Fig. 1, 2) into the chamber 14 (Fig. 1, 2) of the second stage.

Non-combustible large particles are transported by an external flow in the flame tube 2 (Fig. 1, 2) in the direction of the fluidized bed 25 (Fig. 1, 2) located at the end of the flame tube opposite from the nozzle twisting apparatus 6 (Fig. 1, 2, 4) 2 (Fig. 1, 2), for their final gasification, afterburning and separation of ash particles from the flow of gaseous products.

The afterburning in the second stage of the gas obtained in the first stage is carried out by forming a strongly swirling air flow in the flame tube 9 (Fig. 1, 2). Air is introduced into the flame tube 9 (Fig. 1, 2) through the pipe 17 (Fig. 2), from where it moves tangentially along the annular channel 26 (Fig. 2), formed by the inner surface of the housing 8 (Fig. 1, 2) and the outer the surface of the flame tube 9 (Fig. 1, 2), from where air enters the tangential nozzle swirling apparatus 10 (Fig. 2).

The use of the annular channel 26 (Fig. 2) and the tangential air supply into it can improve the reliability of the construction of the heat pipe by reducing the thermal load on its walls.

Passing the tangential nozzle channels 27 (Fig. 6), formed by profiled blades 28 (Fig. 6), the flows are accelerated and exit into the flame tube 9 (Fig. 1, 2), forming a strongly swirling flow in it, with the angular velocity vector being directed identically as the stream leaving the first stage.

Consumption flow rates at the outlet of the tangential nozzle swirling apparatus 10 (Fig. 2) can be adjusted by varying the flow cross-sections of the interscapular channels 27 (Fig. 6), by turning the blades 28 (Fig. 6) around the adjusting fixing pins 29 (Fig. 6) mounted on the end wall 30 (Fig. 6), in which holes 31 are made (Fig. 6) for the air to exit to cool the nozzle 32 (Figs. 1, 2). This allows you to set the workflow mode to the optimal parameters for productivity, environmental and economic characteristics, in addition, the holes 31 (Fig. 6) and the air outlet through them can improve the reliability of the nozzle 32 (Fig. 1, 2) by reducing the thermal load on its wall.

A strongly swirling flow is formed in the flame tube 9 (Fig. 1, 2), consisting of external and internal flows moving with opposite axial velocity components, into the internal flow of which an internal total flow of gasification products of the first stage ejected from the pipe 7 is ejected (FIG. 1, 2) through the hole 15 (Fig. 1, 2). The organization of ejection of gasification products leads to an increase in the productivity of the working process due to an increase in shear axial velocities at the interface between external and internal flows, as well as to an increase in economic characteristics by reducing the power load on external air supply devices to the first stage.

Afterburning is carried out in the combustion zone, inside the pre-chamber 14 (Fig. 1, 2), with the stabilization of the combustion process by radial jets entering through openings 33 (Fig. 4), connecting the internal volume of the pre-chamber 14 (Fig. 1, 2) and covering its volume the flame tube 9 (Fig. 1, 2), as well as the formation of the combustion zone, the intermediate zone and the dilution zone in the internal stream of the flame tube increases the reliability of the combustion process in the second stage by stabilizing it by forming local combustion zones behind the radial jets stabilizing the process Oren.

From the pipe 18 (Fig. 1, 5), communicating with the flow part of the flame tube 9 (Fig. 1, 2) at the opposite end from the tangential nozzle swirling apparatus 10 end (Fig. 2), a mixture of non-combustible fuel components with air is removed, which separate in an external device, such as a cyclone. This leads to an increase in the environmental characteristics of the method due to the absence of emissions from flue gases of solid non-combustible particles into the atmosphere.

The proposed method of burning ground solid fuel and a device for its implementation can significantly increase the efficiency of the working process of burning fuel by increasing productivity, economic and environmental characteristics, expanding the type of fuel burned and increasing the reliability of the working process.

Claims (2)

1. A method of burning crushed solid fuel by gasification in the first stage and afterburning in the second stage, while in the first stage a swirling stream of crushed fuel is created with an excess air coefficient of less than unity, and large particles are sent to the fluidized bed for their final gasification, afterburning, and separation of ash particles from the flow of gaseous products, characterized in that in the first stage create an intensive zone of turbulization of the crushed fuel with air by forming two strongly twisted flows in countercurrent at peripheral speed, with each swirling flow generating external and internal flows moving in countercurrent with axial velocities with respect to external flows, the second stage is made in the form of an afterburner, where external and internal flows moving in countercurrent with axial speeds, and the combustion zone is formed in the internal flow, a mixture of non-combustible components is removed through the corresponding pipe. 2. A device for burning crushed solid fuel, consisting of two stages, the first stage is made in the form of a gas generator, and the second stage is made in the form of an afterburner, characterized in that the fine fraction gasification unit contains coaxial primary countercurrent and secondary countercurrent flame tubes placed between them a turbulization chamber containing a flame tube, the diameter of which is greater than the diameters of the primary countercurrent and secondary countercurrent flame tubes, each primary countercurrent and second Secondary countercurrent flame tubes contain tangential nozzle swirling devices that form a swirl of flows with the opposite direction of angular velocity vectors, while the primary countercurrent flame tube in the plane of the tangential nozzle twisting apparatus contains a pipe coaxial to its central axis, the second stage contains a cylindrical body, flame tube, tangential nozzle swirling apparatus, outlet pipe with a central inlet located in the tangential plane a nozzle swirling apparatus, and an outlet, a prechamber with inlet and outlet openings, while the tangential nozzle swirling apparatus forms a flow swirl that coincides with the direction of the angular velocity vector of the swirl flow in the primary countercurrent flame tube, the air supply pipe, and the discharge of the mixture of solid particles and gas, moreover, the air supply pipe communicates with the tangential nozzle swirling device, and the mixture discharge pipe communicates with the flow part of the flame tube in the opposite end from the tangential nozzle swirling apparatus, and the nozzles are installed tangentially on the inner surface of the casing so that the angular velocity vectors of the air flow and the mixture flow of the residues of solid particles and gas coincide in direction with the angular velocity vector of the air at the outlet of the nozzle swirling apparatus.

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