RU2392544C1 - Furnace for combustion of solid and fuel materials - Google Patents

Abstract

FIELD: heating.

SUBSTANCE: invention relates to processing of solid and fluid materials by fire and can be used in vertical furnaces with separate combustion chamber to combust medical, industrial and domestic wastes. Proposed furnace comprises system of distributed air feed into combustion chamber and after-burning chambers lined with refractory coat mounted vertically and communicated by central hole. Combustion chamber incorporates loading hopper and fire-grate bar arranged above ash collector. After-burning chamber communicates via pipeline with scrubber arranged in parallel therewith and having its outlet furnished with filter of outcoming aerosol. Central hole arranged between chambers that have top end faces representing a rectangular chimney intake is made in the form of a nozzle wherein air feed channels are directed towards after-burning chamber. Oxidising air is distributed in the following weight ratio: one fourth is fed into fire-grate bar, one half is fed into nozzle between aforesaid chambers and the rest is fed into said chambers in equal portions. Outcoming aerosol filter represents two parallel ducts communicated via gate valves with blast fan, each being provided with cascade of replaceable cartridges made from gas-permeable material. Shutter if mounted on after-burning chamber outlet pipeline lever-coupled with turn drive.

EFFECT: higher efficiency of safe and harmless furnace.

3 cl, 4 dwg

Description

The invention relates to a device for processing solid and liquid materials by the fire method and can be used in vertical furnaces with a separate combustion chamber for burning medical, industrial and household waste.

The level of this technical field is characterized by devices for burning lumpy organic fuel, including a combustion chamber connected to each other, connected to a feed hopper, and a chamber for burning gaseous pyrolysis products, communicating with an exhaust pipe with an exhaust pump, while both chambers contain distributed channels for supplying excess air, which provides afterburning to the final oxidation products, as well as a recovery chamber and a collection of removable ash (see, for example, patents RU 2182685, F23G 5/14, 2002 and 559 37, F23G 7/00, 2006).

These compact production furnaces are characterized by a complex structural device and technological maintenance during the combustion of fuel mixtures of various composition and fractionation.

In addition, in the outlet channels and receiver of the described devices, it is possible to recombine dioxins and furans that are not neutralized, which, in the absence of exhaust gas filtering devices, determines the emission of harmful and toxic substances: metal fumes, dioxins, chlorides, furans, polyaromatic hydrocarbons enter the atmosphere .

The noted drawbacks are eliminated in the installation for the thermal processing of solid waste according to patent RU 2137044, F23G 5/14, 1999, which is selected as the closest analogue of the proposed furnace due to the technical nature and the number of matching essential features.

The known installation comprises a combustion chamber with a hopper for loading waste and an outlet for removing ash residue, an afterburner with a gas duct for exhaust gases, a scrubber and a gas filtration unit with a dust storage hopper.

A feature of the known furnace is that the combustion chamber is in communication with the chamber for burning the aerosol products of combustion vertically above it and coaxially with it through an opening in the separation arch, and the gas duct placed perpendicular to the wall of the afterburning chamber is made in the form of a slit heat exchanger of the pipe-in-pipe type.

One end of the inner pipe of the recuperator freely enters the afterburner in its upper part, and the other end of the inner pipe communicates with the chamber for neutralizing harmful and toxic components of the exhaust aerosol.

The placement of the afterburning chamber of incomplete combustion products (carbon dust, carbon monoxide, hydrogen) carried with gas from the coaxial downstream combustion chamber provides optimal conditions for afterburning, since they are connected by the central opening of the intermediate arch, the passage section of which is much smaller than the diameter of the afterburner. In this case, the gas velocity decreases and the products of incomplete combustion with excess oxidizing air are burned to carbon dioxide and water vapor.

In the neutralization chamber, an aerosol at a temperature of 1000-1050 ° C is treated with an alkaline solution injected through a nozzle, while the acidic components are converted into harmless sodium salts.

At the same time, the gas cooled to a temperature of 950-1000 ° C, which is optimal for the reduction of nitrogen oxides, interacts with the urea solution injected through an additional nozzle.

The output of the neutralization chamber is connected to the input of the scrubber, which is placed in such a way that its vertical axis is parallel to the vertical axis of the furnace.

The gas purified in the recuperator from harmful and toxic impurities at a temperature of 850-900 ° C enters the scrubber, where it is rapidly cooled by evaporation of the sprayed water to a temperature of 200-250 ° C, which prevents the recombination of dioxins and furans.

In the cyclone, gas is filtered by centrifugal separation of dust, which is collected in a storage hopper for subsequent disposal in a melting furnace, together with the ash residue from the armrest space of the furnace combustion chamber, and clean gas is discharged through the chimney.

However, a continuation of the advantages of the described installation are the following inherent disadvantages.

The thermodynamic process of two-chamber combustion of solid and liquid materials is not optimized for the residual content of harmful and toxic substances in the exhaust aerosol, which led to the use of an additional neutralization chamber with sequential injection nozzles of various chemical reagents in the slit recuperator, complicating the design of the furnace and the technology for treating furnace gases.

For efficient burning of materials and afterburning of combustion products in the furnace chambers, nozzles of additional fuel dispersed in the volume of thermochemical reactions are used, which increases the efficiency and speed of more complete oxidation. However, this requires additional design improvements and technological measures that increase the cost of work.

In addition, from practical experience it was found that the use of a cyclone in a known device is impractical due to the low efficiency in the filtered mass of dust, the content of which in the exhaust gases after the scrubber is relatively low. At the same time, the occupied production area and the capital costs of manufacturing the installation increase.

The problem to which the present invention is directed, is to simplify the design of the device while increasing its functional reliability with guaranteed achievement of the specified destination.

The required technical result is achieved by the fact that in a known furnace for burning solid and liquid materials, containing a system for distributing oxidizing air in a lined refractory coating, vertically mounted and connected by a central hole, a combustion chamber equipped with a feed hopper and a grate above the ash collector, and a products afterburner combustion, connected by a pipeline to a parallel-mounted scrubber, at the outlet of which a filter for filtering the exhaust aeroso is mounted For, according to the invention, the central hole between the chambers having the upper ends in the shape of a rectangular hog is made in the form of a nozzle in which the air supply channels are directed into the afterburner, the loading hopper is aligned with the screw feeder, and the oxidizing air is distributed in the following mass ratio: quarter under the grate, half into the nozzle between the chambers, in each of which the remainder is equally divided, and the exhaust aerosol filtering device is two connected through the gate valves with the discharge a fan of parallel streams, in each of which a cascade of interchangeable cartridges of gas-permeable material is mounted, the scrubber has a central nozzle, the supply tank of which is installed on its discharge pipe, the screw feeder is located under the rotary grinder of solid material, the feed hopper of which communicates with the exhaust fan, and a shutter is pivotally mounted on the outlet pipeline, through a lever connected to the rotation drive.

Distinctive features provided high-performance autothermal combustion of a variety of solid and liquid materials with almost complete oxidation of the combustion products and continuous stepwise filtering of exhaust gases in a compact installation of a two-chamber furnace, safe and environmentally friendly in operation.

The implementation of the Central hole of the communication of the furnace chambers in the form of a nozzle increases the dynamics of the gas flow of combustion, organizing their supply for afterburning with diluted secondary oxidizing air.

The inclination of the oxidizing air supply channels into the nozzle between the chambers forms the central flow into the afterburner and rarefaction under it, thereby providing the injection of aerosol combustion products from the combustion chamber, which are actively mixed with the injected air, which contributes to the complete oxidation of the combustion products: carbon dust, carbon monoxide hydrogen and so on.

The execution of the upper ends of both chambers in the form of a rectangular hog is aimed at increasing the residence time of the combustion products in the combustion chamber in structurally formed stagnant zones where gas flows are turbulized and the combustion process is activated due to a local increase in the outlet temperature.

The combination of the loading hopper with the screw feeder provides a continuous supply of material for combustion, and a gas barrier to the combustion chamber is formed, which is formed by a tube of compressed bulk material having a high aerodynamic resistance. In this case, the ascending gas flows, including harmful, aromatic and toxic components, are captured and localized by means of a built-in exhaust fan, from which they, mixed with air, are sent to the furnace.

The distribution of the oxidizing air supply over the furnace height, which ensured the autothermal combustion process, was calculated using the mathematical model of the experimental design in the regime of maximum afterburning of pyrolysis products at optimal temperatures in characteristic sections of the combustion and afterburning chambers.

The implementation of the filtering device of the aerosol leaving the scrubber in the form of two parallel streams, in each of which a cascade of interchangeable cartridges of gas-permeable material is mounted, ensures uninterrupted high-quality cleaning of gases from solid inclusions due to the alternate switching of the streams into operation. At the same time, the used filter cartridges are replaced and the efficient filter cartridges are rearranged along the cascade when the stream, which is under preventive maintenance, is blocked on both sides by slide gate valves.

The discharge fan integrated in the discharge pipe creates atomization of the aerosol stream, diluting solid impurities, which are differentially delayed on the filters of sequentially arranged cartridges.

The optimized thermodynamic regime in the furnace of the proposed design ensured high-quality afterburning of combustion products and more complete oxidation of soot, which allows the use of a central nozzle in the scrubber for high-speed evaporative cooling of the aerosol leaving the furnace, thereby preventing the recombination of dioxins and furans.

Placing the capacity of the water pumped into the nozzle of the scrubber on its discharge pipe is a rational use of the free volume of the installation, which organizationally reduces the occupied production area.

The location of the screw feeder under the rotary grinder allows you to expand the technological capabilities of the furnace for the processing of bulky materials that are pre-crushed and fractionated as standard for organized feeding by gravity into the screw hopper.

Equipping the furnace with a damper pivotally mounted on the outlet pipe ensures safe operation, preventing an explosion from an unauthorized pressure surge in the furnace, that is, it functions as an emergency valve.

In addition, the connection of this valve through the lever with the drive (manual) of its rotation serves technological purposes for the formation of traction during ignition and regulation of the temperature parameters of combustion by periodically throttling the operator, if necessary.

Therefore, each essential feature is necessary, and their combination in a stable relationship is sufficient to achieve the novelty of a quality that is not inherent in the signs of disunity, that is, the technical problem posed in the invention is not solved by the sum of the effects, but by a new effect of the sum of the attributes.

A comparative analysis of the proposed technical solution with identified analogues of the prior art, from which the invention does not explicitly follow for a furnace specialist, showed that it is not known, and taking into account the possibility of industrial serial production of a device for burning solid and liquid materials, we can conclude about it eligibility criteria.

The essence of the proposed technical solution is illustrated by drawings, which have purely illustrative purposes and do not limit the scope of claims of the totality of the essential features of the formula. The drawings schematically depict:

figure 1 - two-chamber furnace, a vertical section; figure 2 is a General view of the installation.

A vertically arranged furnace consists of two combined chambers 1 and 2, respectively, of burning a piece of solid or liquid (preferably lumpy) material and afterburning the products of their combustion.

The chambers 1 and 2 are connected by means of a nozzle 3 (Fig. 1), made in the form of a narrowing of the bridge between them, with the upper ends of both chambers 1, 2 having a rectangular profile, forming stagnant zones A and B of the chimney hog, switching camera 1 with camera 2, respectively by means of a nozzle 3 and a chamber 2 with a perpendicularly located outlet pipe 4 (FIGS. 1 and 2).

Along the furnace there is a duct 5 for supplying excess oxidizing air distributed in an optimized mass ratio in height, namely: under the grate 6 - a quarter, into the combustion chamber 1 10-15 wt.%, Into the nozzle 3 half and into the afterburning chamber 2 10-15 wt. .%. Moreover, the channels 7 for supplying oxidizing air to the nozzle 3 are made inclined toward the afterburning chamber 2 at an angle of 30 ° to the vertical.

A technological branch pipe 8 is fixed on the afterburning chamber 2, which is closed by a pivotally mounted flap 9 connected through a lever 10 with a rotation drive, preferably manual.

The hopper 11 of the loading of the combustion chamber 1 with a discrete solid material and / or lumped liquid material communicates with a feed screw 12 (FIG. 2), which is installed under the rotary grinder 13 of a large solid material intended for burning in a furnace.

The feed hopper 14 of the rotary chopper 13 is connected to an exhaust fan 15, the output of which is connected to the duct of the oxidizing air supply duct 5 under the furnace grate 6.

The outlet pipe 4, which is perpendicularly fixed to the afterburning furnace 2, is connected to the scrubber 16, the central nozzle 17 of which communicates via a pump 18 with a water tank 19 installed on the outlet pipe 20, which is connected to the pipe 21.

The exhaust pipe 21, equipped with a discharge fan 22, communicates via two autonomous streams 23 through the slide valves 24 with parallel exhaust aerosol filtering devices 25, each of which is a cascade of exchangeable cartridges 26 made of fibrous filter material, in particular of basalt fiber.

The output of the streams 23, blocked by the slide gate valves 27, is connected to the chimney 28 through an exhaust fan 29.

The device operates as follows.

To ignite the furnace (with the open shutter 9 on the nozzle 8), the furnace chamber is loaded with 1 wood, wood shavings, wood chips, etc., when burned, the temperature rises to the working level of 1200-1400 ° C, after which the shutter 9 is closed and loaded fractional material by rotary feeder 12.

The gases of the ignition mode are released out through the open pipe 8 of the furnace.

Combustion materials are loaded directly into the rotary feeder 12 or into the hopper 14 (in the case of the supply of bulky solid materials or packages in massive boxes). In the rotary grinder 13, the materials from the hopper 14 are fragmented to the specified size and fed to the screw feeder 12, by which they are compacted and fed into the loading hopper 11 of the combustion chamber 1.

The dense mass of the feed material formed in the hopper 11 has a high aerodynamic drag and acts as a gas valve, which allows continuous loading of the furnace, which is comparable in weight to the flow rate of the burned material in the combustion chamber 1 placed on the grid-irons 6.

In this case, oxidizing air is supplied under the grate 6 from the duct 5, which is distributed into the volume of discrete material burned, increasing the combustion area and activating the combustion process and raising the temperature.

An additional volume of excess air is supplied directly to the combustion chamber 1 from the duct 5 by transverse jets, which contributes to the mixing of the exhaust gas combustion products with the secondary air.

The pyrolysis products are inhibited by the rectangular bore of the upper part of the combustion chamber 1 in zone A and are retained therein for at least 2 s, which is sufficient for the oxidation of soot as the most inert and difficult to burn component of any layer burning.

The oxidizing air jets directed from the ducts 7 inclined into the afterburning chamber 2 from the duct 5 create a rarefaction in the nozzle 3, as a result of which the exhaust gases are sucked into the center of the combustion chamber 1 and enter the afterburner 2, where they are inhibited, expanding, and additionally through transverse jets air from the duct 5.

Actively mixing with oxidizing air, the aerosol combustion products are burned to the final products, which is facilitated by the stagnant zone B of the rectangular bore of the upper part of the afterburning chamber 2, which provides a residence time of at least 2 s in the mixture.

The blasting of oxidizing air is optimally distributed in the following mass ratio: 45-50% into nozzle 3, 20-25% under grate 6 and 10-15% into both chambers 1, 2, which creates a positive oxygen balance (30-50%) in the process of burning a combustible mixture.

The proposed furnace design and the thermodynamic combustion regime in it are optimized for the complete combustion of various materials during the oxidation of the components to final products, as evidenced by the almost complete absence of 4 soot pipelines in the exhaust aerosol.

In the furnace it is possible to burn solid organic household and industrial waste, toxic hospital waste containing used bandages, cotton wool, disposable syringes, needles, ampoules, vials, blood transfusion systems, rubber tubes, gloves, etc. materials.

In the pipeline 4, a gas stream with a temperature of 1100-1200 ° C unfolds and at the same time slows down, entering the scrubber 16, where there is a sharp decrease in the temperature of the aerosol due to evaporative cooling by the dispersible nozzle 17 of the water to the level of 250-300 ° C.

The gas-vapor mixture from the scrubber 16 enters through the central pipe 20 into the pipe 21, where, by means of a fan 22, which pumps air into the filter device 25, the aerosol is forcedly mixed with air when the temperature drops to 120-140 ° C.

From the pipeline 22, an aerosol through an open stream 23 (with the slide gate valves 24 and 27 extended) is supplied to the device 25, where a cascade of filtering cartridges 26 passes, in which solid ash particles are retained on the fibrous gas-permeable material.

Pure gaseous waste products are discharged into the pipe 28 by means of a pump 28 and then enter the atmosphere.

Periodically in the device 25, the gate valves 24 and 27 are closed, opening the same gate valves 24, 27 of the second stream 23, thereby connecting the backup filter device 25 to the work.

In the disconnected device 25, the cassettes 26 are replaced by clean ones, preparing it for subsequent work. Thus, the change of filter cartridges 26 is carried out without interrupting the installation process.

Successful testing of a prototype of the installation according to the invention in various modes of burning a variety of solid and liquid materials, certified by instrumentation, allows us to recommend it for mass production for delivery to customers.

Claims (3)

1. A furnace for burning solid and liquid materials, containing a system for distributing oxidizing air into a lined refractory coating, vertically mounted and connected by a central hole, a combustion chamber equipped with a feed hopper and a grate above the ash collector, and a combustion products afterburner connected by a pipeline in parallel an installed scrubber, at the output of which an exhaust aerosol filtering device is mounted, characterized in that the central hole between the chambers, having the upper ends in the shape of a rectangular hog, made in the form of a nozzle in which the air supply channels are directed into the afterburner, the loading hopper is combined with a screw feeder, while the oxidizing air is distributed in the following mass ratio: a quarter under the grate, half in the nozzle between the chambers, in each of which the remainder is equally divided, and the filtering device for the exhaust aerosol consists of two connected through the shutter dampers with a discharge fan of a parallel stream, in each of which n cascade removable cassettes of gas permeable material, and on the outlet conduit is pivotally mounted afterburner flap via a lever connected with the pivot drive. 2. The furnace according to claim 1, characterized in that the scrubber has a central nozzle, the supply tank of which is installed on its discharge pipe. 3. The furnace of claim 1 or 2, characterized in that the screw feeder is located under the rotary grinder of solid material, the loading hopper of which communicates with the exhaust fan.

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