RU2518754C2 - Coal-water fuel combustion device (versions) - Google Patents

Abstract

FIELD: heating.

SUBSTANCE: furnace unit for burning coal-water fuel comprises a lined cylindrical combustion chamber with horizontal rotation axis and flat end face walls, and a cooling chamber screened by steam-generating tubes and fitted by a convection tube bundle inside it; inside the combustion chamber, fuel nozzles are mounted and are communicating with each other by gas bypass ports and serving for both separate and common supply of fuel of different types and primary oxidiser, an ash catcher made as a funnel is set in the lower part of the furnace unit, blast nozzles are set inside the combustion chamber along with tangent supply of the oxidiser and a central fireproof insertion is installed. Additionally below the ash catcher there is an ash-and-slag removal chamber with its dimension in the cross section exceeding the funnel mouth diameter, with an open bottom end face set in a tank with water, with one inclined wall, a scraper conveyor to remove ash and slag is mounted above the bottom and the inclined wall of the tank, the walls of the ash-and-slag removal chamber can be heated. The combustion chamber is installed inside the cooling chamber, the combustion chamber and the cooling chamber communicating by gas bypass ports are fitted by a common lower wall where the ash catcher is set. The ash catcher is installed in the centre of the combustion chamber, the gas bypass ports are placed near its symmetry axes. The lined combustion chamber is placed outside the cooling chamber, at the bottom the combustion chamber is connected to the cooling chamber by gas bypass ports through a gas bypass channel. The ash-and-slag removal chamber is of cylindrical shape and its diameter exceeds the diameter of the ash catcher's funnel mouth by two and more times. For the purpose of heating the ash-and-slag removal chamber, it is connected to the combustion chamber by a pipeline with a built-in ventilator and a heat exchanger is additionally installed before the ventilator.

EFFECT: increase of temperature in furnaces with vertical or horizontal rotation axes up to the ash melting temperature and provision for liquid slag removal, improved efficiency of coal-water fuel combustion and improved reliability of the furnace performance.

15 cl, 6 dwg

Description

The invention relates to devices for burning liquid, including water-coal fuel (HLF) in various boiler plants of industrial heat power engineering, housing and communal services and other heat-generating systems.

Known methods and devices for burning liquid fuel, including coal-water fuel, providing its atomization and blowing into the furnace due to atmospheric air, or hot air, or air and hot flue gases, ignition and stabilization of combustion using tangential swirling of flows [Zaydenvarg V.E. , Trubetskoy K.N., Murko V.I., Not good I.Kh. Production and use of coal water fuel. - M .: Publishing house of Acad. Mining Sciences, 2001. - 176 p.]. These devices have the disadvantage that the combinations of individual nodes are not optimized.

To optimize the operation of individual units of devices for combustion, liquid slag removal is used.

Known boilers with liquid slag removal, which differ structurally depending on the conditions of their work.

In the boiler [RU 2038532 IPC F22B 33/18, publ. 06/27/1995] liquid slag removal is used. The boiler contains a firebox communicated by means of a tap hole and a slag bunker with a slag bath, and the bunker is lowered by the outlet end under the water level in the bath with the formation of a water trap and a cooled coil.

The disadvantage of this boiler is the complexity of the liquid slag removal system.

A known method of preventing clogging of the walls of the units of a coal boiler room with unburned combustion products (WO 2004022928, IPC 7 F01K, publ. March 18, 2004).

The degree of deposition of unburned products of combustion of a coal-fired boiler house on the walls of boiler-house units is reduced by lowering the temperature at the outlet of the furnace below the threshold melting temperature of ash by injecting into the holes formed in the upper part of the furnace, flue gases taken at the exit of the electrostatic precipitator, atomized water, and water sorbent solution, or a mixture of these materials. The temperature of all the materials mentioned is lower than the temperature of the main flue gas stream or additional heat is required to evaporate them.

The disadvantage of this method is the complexity of its industrial implementation.

The closest solution to the proposed option with a horizontal axis of rotation is a furnace device for burning water-coal fuel (RU 2389948, 04/13/2009, IPC 8 F23C 3/00, 8 F23C 7/00], containing a lined combustion chamber and a cooling chamber shielded by heating pipes and including a convective bundle of pipes communicating with each other by means of gas transfer windows, the combustion chamber of which has a cylindrical shape with a horizontal axis of rotation and flat end walls, in which the gas epusknye windows on the front wall of the combustion chamber mounted fuel injectors and the blow nozzle and a combustion chamber mounted within a central refractory insert and the bottom of the ash collector is set, in the shape of a funnel.

The disadvantage of the design of the furnace for burning coal-water fuel is that it does not provide sufficiently uniform temperature fractions inside the combustion chamber over the entire range of changes in fuel consumption necessary for practice. At some CFC costs, intense fuel combustion and a sharp increase in temperature occur in the interaction zone between the fuel plume and the jet of blast air. As a result, particles of coal and ash (especially in the case of using high-ash coals for the preparation of HLW) stick to the walls of the combustion chamber and melt. Slag flowing down the walls of the combustion chamber, falling into zones of low temperature, hardens and problems with ash removal appear. The operation of the furnace becomes unstable.

The closest solution to the proposed option with a vertical axis of rotation is a furnace device for burning liquid fuel [RF Patent 2389945, IPC F23C 3/00, publ. 05/20/2010].

The furnace device includes an external casing with nozzles for supplying fuel and nozzles of secondary air blasting installed in the casing, an internal insert coaxially mounted and the vertical annular combustion chamber formed by them. The inner insert, having the form of a hollow pipe with a diameter of 40 ÷ 60% of the diameter of the boiler body, the lower end of which is open inside the chamber, and the upper also with the open end, the insert is brought out into the heat exchange part of the boiler. The inner insert with its lower end is additionally mounted on a stand inside the firebox and has windows in the lower part. An annular protrusion partially overlapping the annular chamber is mounted on its wall in the lower part of the furnace body. Nozzles for supplying liquid fuel are installed in the middle of the annular chamber, the axis of the nozzles in the horizontal plane is from 30 to 60 degrees with the wall of the furnace. The secondary blast nozzles are located in the horizontal planes of the nozzles approximately 90 degrees from the nozzles along the arc at the intersection of the furnace body with a horizontal plane, and the angles between the nozzle axes and the walls of the furnace at their location are from 30 to 60 degrees.

The disadvantages of this design are the same as those of the above furnace furnace with a horizontal axis of rotation.

The objective of the invention is to increase the temperature in the furnaces with vertical or horizontal axes of rotation to the melting temperature of the ash and the organization of liquid slag removal, increasing the efficiency of combustion of the fuel and oil products and increasing the reliability of the furnace.

The problem is solved using the proposed group of inventions.

According to the first option, in order to achieve the stated objective, a furnace device for burning coal-water fuel is proposed, including a lined combustion chamber of cylindrical shape with a horizontal axis of rotation and flat end walls and a cooling chamber shielded by heating pipes with a convective tube bundle inside it, communicating with each other through gas transfer windows, inside combustion chambers installed fuel nozzles that carry out both separate and joint supply of different types of fuel and of a primary oxidizer, an ash collector made in the form of a funnel is installed in the lower part of the combustion device, and blast nozzles are installed inside the combustion chamber with a tangent feed of the oxidizer and a central refractory insert is installed.

Additionally, an ash and slag removal chamber is installed below the ash collector, having a cross-sectional size exceeding the diameter of the funnel neck, with an open lower end installed in the water bath, with one inclined wall, a scraper conveyor is mounted above the bottom and inclined wall of the bath to remove ash and slag, the camera ash removal is made with the possibility of heating its walls.

Preferably, the combustion chamber is located inside the cooling chamber, the combustion chamber and the cooling chamber communicating with each other by means of gas transfer windows have a common bottom wall on which an ash collector is mounted.

Preferably, the ash collector is installed in the center of the combustion chamber, gas passage windows are located near the axes of its symmetry.

Preferably, the lined combustion chamber is extended outside the cooling chamber, the lower combustion chamber being connected to the cooling chamber by means of gas transfer windows through a gas transfer channel.

Preferably, an ash collector is installed in the bottom wall of the gas passage.

Preferably, the ash removal chamber is made in the form of a cylinder and has a diameter larger than the diameter of the neck of the ash funnel by 2 times or more.

It is preferable for heating the ash and slag chamber, it is connected to the combustion chamber by a pipe with a built-in fan, and in front of the fan an additional heat exchanger is installed.

Preferably, the neck of the ash collector is equipped with an inductive heating system for its walls, with the ability to control the temperature of the walls.

The problem is also solved with the help of the second variant of the combustion device, which includes an external housing of the combustion chamber with nozzles for supplying fuel and nozzles of secondary air blasting installed in the housing, a coaxially mounted internal insert having the form of a hollow pipe, and a vertical annular combustion chamber formed by them, a combustion chamber connected to the cooling chamber by means of gas transfer windows; an ash collector is installed in the lower part of the combustion device.

The ash collector is made in the form of an inclined tray turning into a funnel, an ash removal chamber is installed further below the ash collector, having a cross section larger than the diameter of the neck of the funnel, with an open lower end installed in the water bath, with one inclined wall, one bottom and one inclined wall the bathtub is equipped with a scraper conveyor for removing ash and slag, the ash and slag removal chamber is made with the possibility of heating its walls.

Preferably, the hollow tube has a diameter of 20-60% of the diameter of the combustion chamber body.

Preferably, the lined combustion chamber is extended outside the cooling chamber, the lower combustion chamber being connected to the cooling chamber by means of gas transfer windows through a gas transfer channel.

Preferably, an ash collector is installed in the bottom wall of the gas passage.

Preferably, the ash removal chamber is made in the form of a cylinder and has a diameter larger than the diameter of the neck of the ash funnel by 2 times or more.

It is preferable for heating the ash and slag chamber, it is connected to the combustion chamber by a pipe with a built-in fan, and in front of the fan an additional heat exchanger is installed.

Preferably, the neck of the ash collector is equipped with an inductive heating system for its walls, with the ability to control the temperature of the walls.

The technical result of the proposed group of inventions is to increase the temperature in the furnaces with vertical or horizontal axes of rotation to the melting temperature of the ash and the organization of liquid slag removal, increasing the efficiency of combustion of HLW and increasing the reliability of the furnace.

Specific embodiments of the combustion device with horizontal and vertical axes of rotation of the combustion chamber are presented in the drawings.

1 and 2 show a longitudinal and cross section of the proposed furnace device with a horizontal axis of rotation of the combustion chamber in the embodiment when the combustion chamber is placed inside the cooling chamber. On figa shows a longitudinal section of the device when the combustion chamber is placed outside the cooling chamber.

Figure 3, figure 4, figure 5 shows the longitudinal and cross sections of the combustion device with a vertical axis of rotation.

A device for burning water-coal fuel (options) includes (figure 1, figure 2, figure 2a, figure 3, figure 4, figure 5)

1 - cooling chamber; 2 - heating pipes; 3 - convective bundle of pipes of the cooling chamber; 4 - a combustion chamber; 5 - end walls of the combustion chamber; 6 - gas passage windows; 7 - a central insert; 8 - blow nozzle; 9 - the front wall of the combustion chamber; 10 - fuel nozzles; 11 - ash collector; 12 - throat funnel neck; 13 - box ash removal chamber; 14 - pipeline; 15 - fan; 16 - a bath; 17 - conveyor, 18 - heat exchanger; 19 - gas passage channel, 20 - inclined tray.

Inside the cooling chamber 1 of the combustion device, boiling pipes 2, a convective bundle of pipes 3 are installed. The combustion chamber 4 with end walls 5, in which the gas passage windows 6 are installed, is installed inside the cooling chamber (Fig. 1).

The combustion chamber 4 and the cooling chamber 1 communicate with each other by means of gas transfer windows 6, have a common lower wall on which an ash collector 11 is mounted.

On figa shows a variant of the combustion device in which the combustion chamber 4 is installed outside the cooling chamber 1.

A central insert 7 is mounted inside the combustion chamber 4. A blower nozzle 8 and fuel nozzles 10 are installed on the front wall 9. An ash collector 11 with a mouth 12 is installed in the lower part of the combustion chamber 4 or in the lower wall of the gas transfer duct 19. A vertical duct 13 is installed below the ash collector 11. ash removal, which is made in the form of a cylinder and has a diameter greater than the diameter of the neck of the funnel 12 of the ash collector 2 times, with a pipe 14 connected to it, including a fan 15. An open bottom end box 13 of the ash removal chamber is immersed in the water contained in the bath 16. Inside the bath 16 there is a scraper conveyor 17 for unloading ash and slag from the bath.

As nozzles, fuel nozzles known from the prior art are used. Preferably, the nozzles described in RF patent No. 2346756 are used.

Figure 3, 4, 5 shows one of the possible furnace devices according to the second embodiment of the invention with a vertical axis of rotation.

Figure 3 shows the lined combustion chamber 4, taken outside the cooling chamber 1, and at the bottom of the combustion chamber 4 is connected to the cooling chamber 1 through the gas transfer window 6 through the gas transfer channel 19.

In the center of the combustion chamber 4, a hollow pipe is installed. The ash collector 11 is made in the form of an inclined tray 20, turning into a funnel.

All other positions indicated in FIG. 3 are similar to those indicated in FIG. 2a.

The operation of the device according to the first embodiment of the invention is as follows.

When starting the combustion device, highly reactive liquid fuel, for example diesel fuel, is fed into the combustion chamber 4 through the fuel nozzles 10, an oxidizer is blown through the nozzles 8, and a combustion mode is organized in the combustion chamber 4. Due to the heat generated during the combustion of the fuel, the walls of the combustion chamber 4 and the central insert 7 are heated. After heating the walls of the combustion chamber 4 to a temperature of 400-500 ° C, carbon dioxide is added to diesel fuel in a small proportion. With a further increase in temperature inside the combustion chamber 4, the fraction of diesel fuel in the supplied mixture decreases, and the fraction of the fuel-injection unit increases until the boiler reaches the calculated mode of operation on coal-water fuel without diesel fuel.

The airborne stream created by the nozzle 10 is twisted in an annular channel into a vortex flow. The blast gas enters the combustion chamber 4 tangentially to its walls and supports the flow swirl inside the chamber. Thus, the gas enters the combustion chamber 4 tangentially to its walls and leaves the chamber through the gas transfer windows 6 located on the end walls 5 of the combustion chamber 4 near their rotation axes. Therefore, the gas flow velocities in almost the entire volume of the combustion chamber 4 have a tangential component and a radial component directed to the axis of symmetry of the combustion chamber 4. A drop of HLW (or a particle of coal) falling into such a stream under the action of centrifugal forces due to the tangential components of the flow velocity tends to get to the wall of the combustion chamber 4, but radial gas flows impede this movement. As a result, a stratification of the flow of droplets (and coal particles) occurs: the largest droplets are carried into outer orbits, the smallest are closer to the axis of the combustion chamber 4. Due to the heat received from the combustion of diesel fuel at the initial stage, and then coal, as well as heat, reradiated by the walls of the combustion chamber 4 and the inner insert 7, heating, drying, ignition, and then intense combustion of coal particles occur. As coal burns out, the mass of particles decreases, the centrifugal forces acting on these particles decrease, and the particles move into circular orbits with a smaller radius. In this case, particles with a larger mass are in the combustion zone for a longer period of time and, as a result, all coal particles have time to burn out within the combustion chamber 4.

In operating modes, the operation of the boiler is most effective at high temperatures in the furnace. VUT has its own specifics. If the temperature in the combustion chamber 4 is not higher than the melting temperature of the ash, falling into the zone of low temperature, the coal does not have time to dry out, ignite and burn out in the VUT drop. If the average temperature in the combustion chamber 4 is close to the melting temperature of the ash, then in some places the ash melts, in others it does not, and there are problems with ash removal. The most effective modes are those in which the temperature inside the combustion chamber 4 almost everywhere exceeds the melting temperature of the ash. Particles of molten ash have a sufficiently high density and low windage. Therefore, even small particles of slag are deposited on the walls of the combustion chamber 4. Here they form a thin layer of slag, which flows down first along the walls of the combustion chamber 4, then the ash collector 11 and then through the mouth 12 of the ash collector 11 falls into the water without touching the walls of the box of the ash removal chamber 13. Due to the fan 15 pumping hot gas from the duct of the ash removal chamber 13 to the combustion chamber 4 through a pipe 14 inside the ash removal chamber 13, a high temperature is maintained that does not allow solidification of the slag in the neck 12 of the ash catcher.

An alternative to this technical solution is the installation, for example, of an inductive heating system for the neck 12 of the ash collector. As inductive heating systems, known from the prior art and used for similar purposes can be used.

The operation of the device according to the second embodiment with a vertical axis of rotation, Figs. 3, 4, 5, is similar to the operation of the device according to the first embodiment described above. This option is preferably used in boilers of high power, when the combustion chamber is large and the manufacture of the camera body with a horizontal axis of symmetry and the installation of the central body are difficult.

The proposed group of inventions allows to achieve a technical result when using them on different compositions of fuels.

When using boilers, there are no problems with slagging of heating surfaces of the furnaces.

The implementation of the invention.

In the village of Moshkovo, Novosibirsk Region, a boiler with layer-by-layer burning of coal was converted to burning coal in the form of coal-fired fuel. At the first stage, the proposed liquid slag removal system was not organized on the boilers. During the operation of the boiler, there were problems with the slagging of the heating surfaces and ash removal when using coals with high ash content for the production of HLW. The installation of a liquid slag removal system allowed to increase the temperature inside the furnace to values of the order of 1500 degrees, significantly increase heat generation and ensure high stability of the boiler furnace.

Claims (15)

1. A combustion device for burning water-coal fuel, including a lined combustion chamber with a cylindrical shape with a horizontal axis of rotation and flat end walls, and a cooling chamber shielded by heating pipes with a convective bundle of pipes inside it, communicating with each other through gas transfer windows, fuel nozzles are installed inside the combustion chamber carrying out both separate and joint supply of different types of fuel and primary oxidizer, in the lower part of the combustion device installed The ash collector is made in the form of a funnel, and the blow nozzles are installed inside the combustion chamber with a tangent feed of the oxidizing agent and a central refractory insert is installed, characterized in that an ash removal chamber is installed further below the ash collector, having a cross section larger than the diameter of the neck of the funnel with the bottom open an end face mounted in a bath with water, with one inclined wall, a scraper conveyor is mounted above the bottom and the inclined wall of the bath to remove ash and slag, oshlakoudaleniya configured to heat its walls. 2. The combustion device according to claim 1, characterized in that the combustion chamber is located inside the cooling chamber, the combustion chamber and the cooling chamber communicating with each other by means of gas transfer windows have a common bottom wall on which an ash collector is mounted. 3. The furnace device according to claim 2, characterized in that the ash collector is installed in the center of the combustion chamber, gas transfer windows are located near the axis of its symmetry. 4. The combustion device according to claim 1, characterized in that the lined combustion chamber is moved outside the cooling chamber, and at the bottom of the combustion chamber is connected to the cooling chamber by means of gas passage windows through a gas passage. 5. The furnace device according to claim 4, characterized in that an ash collector is installed in the lower wall of the gas transfer channel. 6. The furnace device to any one of claims 1 to 5, characterized in that the ash removal chamber is made in the form of a cylinder and has a diameter greater than the diameter of the neck of the funnel of the ash collector by 2 times or more. 7. The combustion device according to any one of claims 1 to 5, characterized in that for heating the ash and slag removal chamber, it is connected to the combustion chamber by a pipe with a built-in fan, and a heat exchanger is additionally installed in front of the fan. 8. The furnace device according to any one of claims 1 to 5, characterized in that the neck of the ash collector is equipped with an inductive heating system for its walls, with the ability to control the temperature of the walls. 9. A combustion device, including an external housing of the combustion chamber with nozzles for supplying fuel and nozzles of secondary air blasting installed in the housing, a coaxially mounted internal insert having the shape of a hollow pipe, and a vertical annular combustion chamber formed by them, the combustion chamber is connected to the cooling chamber by gas transfer windows, in the lower part of the furnace device an ash collector is installed, characterized in that the ash collector is made in the form of an inclined tray turning into a funnel, the ash collector is equipped with an ash removal chamber having a cross-sectional size exceeding the diameter of the funnel neck, with an open lower end installed in a water bath, with one inclined wall, a scraper conveyor is mounted above the bottom and inclined wall of the bathtub to remove ash and slag, and an ash removal chamber made with the possibility of heating its walls. 10. The combustion device according to claim 9, characterized in that the hollow pipe has a diameter of 20 ÷ 60% of the diameter of the combustion chamber. 11. The combustion device according to claim 9, characterized in that the lined combustion chamber is moved outside the cooling chamber, and at the bottom of the combustion chamber is connected to the cooling chamber by means of gas passage windows through a gas passage. 12. The furnace device according to claim 11, characterized in that an ash collector is installed in the lower wall of the gas transfer channel. 13. The combustion device according to any one of claims 9 to 12, characterized in that the ash and slag removal chamber is made in the form of a cylinder and has a diameter larger than the diameter of the neck of the funnel of the ash collector by 2 times or more. 14. The combustion device according to any one of claims 9 to 12, characterized in that for heating the ash and slag removal chamber, it is connected to the combustion chamber by a pipe with a built-in fan, and an additional heat exchanger is installed in front of the fan. 15. The furnace device according to any one of paragraphs.9-12, characterized in that the neck of the ash collector is equipped with an inductive heating system for its walls, with the ability to control the temperature of the walls.

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