RU2539414C2 - Apparatus for burning solid fuel in pulsating flow - Google Patents

Abstract

FIELD: power generation.

SUBSTANCE: invention relates to thermal power, particularly apparatus for burning solid low-reactivity fuels, e.g. spent tyres or rubber wastes, in order to recycle heat, with low concentration of carcinogenic substances in combustion products thereof. The apparatus for burning solid fuel in a pulsating flow comprises an ignition chamber, a chamber for the preliminary heat preparation of the fuel, a cover for the chamber for the preliminary heat preparation of the fuel, an air conduit, a resonator pipe consisting of two parts (top and bottom) and adjoining the ignition chamber to form an annular gap between its top and bottom parts, a mesh turbulator consisting of multiple component parts, a grate, a multi-nozzle diffusion burner, a solid waste collector and an inert material collector. The apparatus is provided with a flue pipe, the top section of which is located in the chamber for the preliminary heat preparation of the fuel at a distance of 2-3 times the diameter of the said pipe from the bottom part of the cover of the chamber for the preliminary heat preparation of the fuel, the other end is located in the bottom part of the resonator pipe and the apparatus also includes a system for automatic control of the temperature of thermal decomposition of rubber, with a temperature sensor of a temperature control system, one end of which is attached to the ignition chamber, the second end is located opposite the air conduit to allow the connection and control of the flow cross-section thereof, wherein the air conduit is in the form of an aerodynamic valve with a variable flow cross-section, which enables maintaining, in the ignition chamber and the chamber for the preliminary heat preparation of the fuel, a given gas temperature in an automatic mode and thermal decomposition of wastes of industrial rubber articles to allow the release of light fractions for further combustion, wherein the inert material collector is fitted with a system for lowering the temperature of the inert material, which is in the form of a group of atomisers arranged symmetrically on the diameter of the inert material collector, and the number of the atomisers is defined by the volume of the cooled inert material.

EFFECT: highly efficiency and environmentally safe apparatus for recycling solid fuel, particularly scrap tyres.

2 dwg

Description

The invention relates to a power system and ecology, in particular, to devices for burning solid low-reactive fuels, for example spent tires, or rubber waste for the purpose of heat recovery, when their products of combustion contain a low concentration of carcinogenic substances.

A device for burning rubber waste containing a cyclone is known, in which large particles are burned to a certain size and carried away by a stream, an ignition chamber, a resonator tube for burning unburned combustible elements (Sat. Vibration combustion in some model devices. Kazan, KSU, 1970 , p. 148-149).

The disadvantage of the above device is the need to crush the tires into pieces, the instability of vibrational combustion associated with the uneven supply of fuel to the ignition chamber, the large mechanical entrainment of harmful combustion products from the resonator pipe into the atmosphere.

A device is also known that contains an ignition chamber, an adjacent resonant tube, air ducts, a preliminary heat treatment chamber for fuel (AS USSR 237324, IPC F23d 11/34, 1969, BI No. 8).

This device has such a disadvantage as a breakdown of vibrational combustion, arising due to poor heat treatment of the fuel in the chamber, due to the lack of the ability to control the supply of combustible elements with strong gusts of wind. In case of disruptions in the flow pulsations, the ignition zone moves into the resonance tube, and the design of the device does not allow the combustion to return to pulsation mode. As a result of this, environmental parameters at the cut of the resonant tube are sharply deteriorating. This device does not provide the ability to retain mechanical impurities carried by the stream into the environment and protect it from thermal pollution. This device also implies the need for preliminary mechanical processing of fuel in order to turn it into a dust form, as a result of which, this device is inefficient and leads to a decrease in the efficiency of the unit.

The closest, in technical essence and the claimed technical solution, selected as a prototype, is a "Device for burning fuels in a pulsating flow", containing: an ignition chamber, a chamber for preliminary thermal preparation of fuel (hopper), a cover for a chamber for preliminary thermal preparation of fuel, air ducts, resonator a pipe consisting of two components, a grate, a turbulizer, an ash pan, a diffusion burner (Utility Model Patent of the Russian Federation No. 11302, IPC F23D 11/34, published September 16, 1999).

The disadvantages of this technical solution are: 1) during the multiple loading of the installation with solid fuel due to the physical phenomenon of condensation on the inner wall of the chamber of preliminary heat treatment of the fuel, the deposition of volatile components (gummy mass) occurs. As a result, the volume of the chamber is reduced, which prevents the laying of the next batch of solid fuel. In addition, complete fire safety is not ensured, which is associated with the accumulation of flammable combustible (resinous) substances on the inner walls of the chamber for preliminary thermal preparation of fuel; 2) due to the design features of the installation, the environment is not protected from harmful emissions, since at high temperatures (more than 450 ° C) sulfur compounds are formed in the preliminary heat treatment chamber of the fuel, which, together with the exhaust products of combustion, enter the atmosphere; 3) the product of tire processing in a device for burning solid fuel in a pulsating flow is a solid residue in the form of burnt soot, which leads to the loss of valuable material in the form of an inert powder. All this leads to a decrease in environmental friendliness, safety, efficiency, and in general - the inefficiency of the installation.

The object of the invention is the creation of a highly efficient installation that provides fire safety and completeness of combustion of the disposal process, while improving environmental friendliness and efficiency.

The technical result of the claimed technical solution is the creation of a highly efficient economically and environmentally friendly installation for the disposal of solid fuels, in particular, worn tires.

The specified technical result is achieved in that a device for burning solid fuel in a pulsating flow containing an ignition chamber, a chamber for preliminary thermal preparation of fuel, a cover for a chamber for preliminary thermal preparation of fuel, an air duct, a resonator tube consisting of two parts (upper and lower) and connected to to the ignition chamber, forming an annular gap between its upper and lower parts, a mesh turbulator, consisting of several components, a grate, a multi-nozzle diffusion mount a Christmas tree, a collection of solid waste, a collection of inert material, is equipped with a gas exhaust pipe, the upper cut of which is located in the chamber of preliminary heat treatment of fuel at a distance of 2-3 diameters of this pipe from the bottom of the cover of the chamber of preliminary heat treatment of fuel, the other end is located at the bottom of the resonator pipe and introduced an automatic temperature control system for thermal decomposition of rubber, with a temperature sensor of the temperature control system, one end of which is attached to the ignition chamber the second end is located opposite the air duct with the possibility of connecting and regulating its flow cross-section, and the air duct is made in the form of an aerodynamic valve with a variable flow cross-section, which ensures that the gas temperature in the ignition chamber and in the preliminary heat preparation chamber of the fuel in automatic mode and thermal decomposition waste rubber products with the possibility of separation of light fractions for further burning, moreover, in the collection of inert material p A system for reducing the temperature of an inert material is placed, which is made in the form of a group of nozzles arranged symmetrically in diameter of the inert material collector, and the nozzles are installed in an amount determined by the volume of cooled inert material.

New in the device is:

The proposed device allows you to choose the optimal, cost-effective mode of operation of the installation with a cyclic supply of solid fuel due to the removal through the gas exhaust pipe of the solid fuel combustion products formed in the preliminary heat treatment chamber of the fuel, which form a resinous mass on its inner walls, thereby reducing its volume. Also, when processing tires in a device for burning solid fuels in a pulsating flow, an inert material is obtained consisting of 75-85% of soot, 5-10% of sulfur and 10-20% of mineral substances, which is a good raw material in the manufacture of rubber products, road construction . The output of gaseous products of combustion is environmentally friendly due to the design of the device for burning solid fuels in a pulsating flow and avoiding the liquid fraction in the process of processing tires.

To clarify the technical essence of the invention, we consider the drawings: FIG. 1 is a schematic diagram (general view) of the claimed device, FIG. 2 is a device for burning solid fuel (specific embodiment), where:

1 - ignition chamber,

2 - grate,

3 - shock mechanism (vibration hammers),

4 - the upper part of the resonator tube,

5 - the lower part of the resonator tube,

6 - ring gas burner with electric igniter,

7 - a system for reducing the temperature of an inert material,

8 - duct

9 - chamber preliminary heat treatment of fuel,

10 - collection of solid waste,

11 - cover of the chamber for preliminary heat treatment of fuel,

12 - lever with a latch,

13 - plate

14 - cable

15 is a collection of inert material,

16 - hatch of the inert material collection,

17 - cylindrical heat exchanger,

18 - inlet fitting

19 - output fitting

20 - multi-nozzle diffusion burner,

21 - window with a plug

22 - mesh turbulator,

23 - exhaust pipe

24 - ash collector

25 - electric motor with gear

26 - frame base, welded from steel corners,

27 - worn tires

28 - temperature sensor temperature control system,

29 - block automatic temperature change.

The thermoreactor is made in the form of a cylinder and consists of an ignition chamber 1, a preliminary heat treatment chamber for fuel 9, and a solid waste collector 10. In the inventive device, a preliminary heat treatment chamber for fuel 9 of a cylindrical shape with a lid of the preliminary heat preparation chamber for fuel 11. For opening and closing the lid a chamber with preliminary thermal preparation of fuel 11 is provided with a latch 12. A plate 13 is placed inside the chamber of preliminary thermal preparation of fuel 9, which serves to reducing the volume of disposed worn tires 27 as they burn out. The plate 13 is connected to the lid of the chamber for preliminary thermal preparation of fuel 11 with a cable 14, designed to lift the plate 13, when opening the lid of the chamber for preliminary thermal preparation of fuel 11. The lid of the chamber for preliminary thermal preparation of fuel 11 is locked in the open position.

A solid waste collector 10 with an inert material collector 15 with a hatch of an inert material collector 16 is attached to the base of the preliminary thermal preparation of fuel 9 chamber to remove inert material (waste). An air duct 8 is connected to the solid waste collector 10. An annular gas burner with an electric igniter 6 is located under the grate 2. Ignition chamber 1 is connected to the resonator pipe, which consists of two parts - the upper 4 and lower 5. A cylindrical heat exchanger 17 is mounted on the upper part of the resonator pipe 4 with inlet and outlet fittings 18 and 19, respectively. A multi-nozzle diffusion burner 20 is attached to the base of the upper part of the resonator tube 4. For ignition of the burner, there is a window with a plug 21 on the lateral surface of the ignition chamber 1. A mesh turbulator 22 consisting of several component parts (plates) is placed above the multi-nozzle diffusion burner 20. Moreover, the gap between the plates is adjustable. The lower part of the resonator tube 5 is connected to the ignition chamber 1 by means of a pipe in which it moves freely along its axis. The upper section of the exhaust pipe 23 is located at a distance of 2-3 diameters of this pipe from the lower part of the lid of the chamber for preliminary heat treatment of fuel 11, and the lower one is in the lower part of the resonator pipe 5.

A device for burning solid fuel in a pulsating flow works as follows:

The lever 12 opens the lid of the chamber for preliminary thermal preparation of fuel 11, which pulls the plate 13 with a cable 14. In the open position, the lid of the chamber for preliminary thermal preparation of fuel 11 is held by a latch. Worn tires 27 are loaded into the chamber of preliminary thermal preparation of fuel 9 (Fig. 2). The cover of the chamber for preliminary thermal preparation of fuel 11 is closed and fixed with a latch. In this case, the plate 13 fits snugly on the upper tire. Tight closing of the chamber for preliminary thermal preparation of fuel 9 is provided by a sealing device between the chamber for preliminary thermal preparation of fuel 9 and the cover of the chamber for preliminary thermal preparation of fuel 11. An electric igniter ignites combustible gas entering an annular gas burner with an electric igniter 6, which ignites worn tires 27. The temperature in the preliminary heat treatment chamber of the fuel 9 is maintained in the range from 350 to 450 ° C. The temperature is controlled by mixing air into the heated gases entering the chamber for preliminary heat treatment of the fuel 9 through the air duct 8, which acts as an aerodynamic valve. To this end, the claimed device provides a system for controlling the air supply to the chamber for preliminary heat treatment of fuel 9, including a temperature sensor of the temperature control system 28 (Fig. 2), an automatic temperature change unit 29, and air duct 8. When the temperature in the chamber for preliminary heat treatment of fuel 9 increases above 450 ° C the temperature sensor of the temperature control system 28 captures the temperature, the automatic temperature change unit 29 reduces the flow area of the duct 8, performing fun aerodynamic valve, air access to the combustion area decreases, and at temperatures below 350 ° C increases. Accordingly, the intensity of combustion (thermal decomposition) decreases or increases. At this temperature, volatile constituents containing combustible elements are released from the worn tires 27 in the preliminary thermal preparation chamber for fuel 9 and enter the resonator tube 4, 5 for subsequent afterburning. As the worn tires 27 burn out using the impact mechanism 3, operating in the frequency range of 1-10 Hz with a frequency of 3 cycles per 1 hour, a cycle time of 5 minutes, the inert material is separated from the metal cord. The temperature of solid waste and inert material is high, therefore, a system for reducing the temperature of inert material 7 is provided in the inert material collector 15, while lime water is automatically injected when the percussion mechanism 3 is operated, and also if the temperature in the inert material collector is exceeded 450 ° C. The number of nozzles spraying lime water is calculated based on the volume of the inert material collector 15 and the volume of inert materials that are cooled waste. For example, with a total volume of inert materials collection equal to 4 m ³ , 12 nozzles with a diameter of 10 ... 12 mm are necessary and sufficient, and with a volume of 2 m ³ , for example, 6 nozzles will be necessary, with a volume of, for example, 8 m ³ , 24 nozzles are needed, located symmetrically in diameter of the inert materials collection (for the calculation of the number of nozzles, see the description section “example of a specific design”). The use of lime water increases the environmental friendliness of the device, since it reacts with gaseous pollutants, including sulfur oxide, which are adsorbed with subsequent sedimentation in the inert material collection 15.

The thermal decomposition products of worn tires 27 (volatile constituents) containing a large number of combustible elements enter the mesh turbulator 22 through the annular gap between the upper 4 and lower 5 parts of the resonator tube 22. When a multi-nozzle diffusion burner 20 operating on gas or liquid fuels is turned on, products thermal decomposition of worn-out tires (gas waste) is turbulized behind the mesh turbulator 22 and ignited. A flat combustion zone is formed, located at a height of one quarter of the total length of the resonator tube, where acoustic vibrations are excited, which contribute to the vigorous mixing of the gas-air mixture. Air is supplied to the combustion zone from the lower part of the resonator pipe 5. The decomposition products of worn tires 27 accumulated in the preliminary heat treatment chamber 9 through the exhaust pipe 23 are sucked into the lower part of the resonator pipe due to the ejection effect. Unburned elements contained in the combustion products of burning rubber, passing through the high-temperature zone, completely burn out, increasing the heat stress of this zone.

As a sufficient temperature is established in the preliminary heat treatment chamber of the fuel 9, the combustible gas entering the annular gas burner with an electric igniter 6 is turned off. In the combustion zone, a temperature in the range 350 ° C-450 ° C is maintained, the worn tires 27 are decomposed thermally. When passing combustible gases (volatile constituents) through the mesh turbulator 22, they mix with secondary air and actively burn the combustible elements. As a result, the thermal tension of the mesh turbulator 22 remains high enough to maintain a self-oscillating process. In the resonator tube, the combustion products make an oscillatory movement, which increases the heat transfer from the gas to the wall and prevents slag deposits on the walls of the resonator tube 4, 5.

An example of a specific implementation (figure 2).

A device for burning solid fuel in a pulsating flow is a fire apparatus operating on the principle of pulsating combustion. The combustion process is carried out in two stages: 1) gasification of rubber wastes in a reducing environment, 2) afterburning of gaseous products in the pulsation mode in the resonator tube.

A device for burning used tires is mounted on a frame base 26 welded from steel corners. An ash collector is attached to the upper part of the resonator pipe 4. The position of the lower part of the resonator pipe 5 is changed by an electric motor with a reducer 25.

By means of a hoist, worn tires 27 are loaded into the chamber for preliminary heat treatment of fuel 9. Rubber waste is ignited by Flame-1 household gas burners operating on gas fuel (propane C ₃ H ₈ ). The amount of air required for combustion flows through duct 8. After the rubber ignites, the gas burners turn off. Time to reach the operating mode is 18-20 minutes. Subsequently, the combustion of rubber in the preliminary heat treatment chamber of the fuel 9 occurs without accompanying combustible gas.

The temperature in the chamber for preliminary heat treatment of fuel 9 is maintained in the range of 350 ° -450 ° C. The temperature is controlled by mixing air into the heated gases entering the ignition chamber 1. For this purpose, the claimed device provides a system for supplying air to the chamber, including a temperature sensor of the temperature control system 28, an automatic temperature change unit 29 and an air duct 8. When the temperature in the ignition chamber rises 1 and in the chamber for preliminary thermal preparation of fuel 9 above 450 ° C, the temperature sensor of the temperature control system 28 records the temperature, the automatic change unit Ia temperature 29 reduces the passage section of the duct 8 performing the function of the aerodynamic valve, the airflow in the combustion region decreases, and at a temperature below 350 ° C increases. Accordingly, the combustion rate decreases or increases. At this temperature, volatile constituents are emitted from the worn tires 27 in the fuel pre-preparation chamber 9 from the exhaust pipe 23, the upper cut of which is located from the lower part of the cover of the preliminary thermal fuel preparation chamber 11 at a distance of 2-3 pipe diameters (distance from the upper cut the gas outlet pipe to the lower part of the cover of the chamber for preliminary heat treatment of fuel 11 is 2-3 diameters, since under the action of Archimedes forces volatile components are concentrated in the upper part of the chambers pre-heat fuel preparation 9), enter the resonator tube 4, 5 for post-combustion, and mixing in with the secondary air are combusted in the burst mode. With an excessive increase in the air flow velocity (more than 8 m / s), the self-oscillations disappear in the resonator tube, since the Rayleigh criterion is not fulfilled. To reduce the air flow rate, the distance between the grids of the mesh turbulator must be reduced. This leads to an increase in hydrodynamic drag - a decrease in air flow rate. In the resonator pipe, the combustion products oscillate, which increases the heat transfer from the gas to the wall and prevents slag deposits on the pipe walls. The metal cord and part of the solid residue are lowered into the solid waste collector 10, and the inert material is lowered into the inert material collector 15. The inert material is cooled using the inert material temperature reduction system; for this, nozzles located symmetrically in diameter of the inert material collector spray lime water, which cools inert material. When the height of the inert material collector is h = 1.95 m, the radius is R = 1.4 m, the volume of the inert material _collector is _{V sr} . _Inert.mat = 4 m ³ . For complete wetting and cooling of the inert material, it is necessary _{V wet} = 0.8 m ^{3 of} lime water. Symmetrically, according to the diameter of the inert material collector, standard nozzles are installed, with a diameter of d = 10 ... 12 mm = 0.01 ... 0.012 m. The flow of lime water through one nozzle is Q = S _f · υ), (Q is the flow of lime water through 1 nozzle, S _f - nozzle cross-sectional area, υ - lime water flow rate) Q = S _ф · υ = π · r ² · υ = 3.14 · 0.0062 · 10 = 0.001 m ³ / s (at a flow rate of lime water 10 m / s). Spray time t = 1 min = 60 s. V _water through 1 nozzle = Q · t = 0.001 · 60 = 0.06 m ³ . The required number of nozzles n = V is _wetted / V _water through 1 nozzle = 0.8 / 0.06 = 12 nozzles. Loading tires is carried out cyclically without mechanical crushing.

Thus, in comparison with the known analogues, the advantage of the claimed technical solution is the creation of a highly efficient installation that allows to increase fire safety, due to the design feature - the introduction of a gas outlet pipe working on the ejection effect, due to the introduction of a temperature control system, and the completeness of combustion of the disposal process, by maintaining a constant volume of the chamber for preliminary heat treatment of fuel, which increases environmental friendliness. And the economy is increased due to the same design features, as a result of which there will be no deposits of resinous masses on the inner walls of the chamber for preliminary heat treatment of fuel, and, therefore, the need for additional time and material costs for cleaning the inner walls of the chamber is eliminated.

Claims (1)

A device for burning solid fuel in a pulsating flow containing an ignition chamber, a preliminary heat preparation chamber, a cover of a preliminary heat preparation chamber, an air duct, a resonator tube consisting of two parts (upper and lower) and adjoined to the ignition chamber, forming an annular gap between its upper and lower parts, a mesh turbulator, consisting of several components, a grate, a multi-nozzle diffusion burner, a collection of solid waste, a collection of inert mate iala, characterized in that it is equipped with a gas exhaust pipe, the upper cut of which is located in the preliminary heat treatment chamber of fuel at a distance of 2-3 diameters of this pipe from the lower part of the cover of the preliminary heat treatment chamber of fuel, the other end is located in the lower part of the resonator tube and an automatic control system is introduced thermal decomposition temperature of rubber, with a temperature sensor of a temperature control system, one end of which is attached to the ignition chamber, and the other end is located on opposite the air duct with the possibility of connecting and regulating its flow cross-section, the air duct being made in the form of an aerodynamic valve with a variable flow cross-section, which ensures that the gas temperature in the ignition chamber and in the preliminary heat preparation chamber is maintained at a given temperature in the automatic mode and thermal decomposition of waste rubber products with the possibility of separation light fractions for further combustion, and in the collection of inert material there is a temperature reduction system rounds of inert material, which is made in the form of a group of nozzles arranged symmetrically in diameter of the inert material collector, and the nozzles are installed in an amount determined by the volume of cooled inert material.

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