RU2294494C1 - Device for burning fuel in rotating furnace - Google Patents

Abstract

FIELD: combustion.

SUBSTANCE: device comprises housing of the exit nozzle made of a conical recess whose generatrix is inclined to the axis of the housing at an angle of 25-35°, fuel supply needle arranged in the zone of the conical recess of the exit nozzle for permitting movement with respect to the exit nozzle and mounted with a spaced relation to the nozzle, passage for supply of oxidizer defined by the outer surface of the fuel-supplying needle and inner side of the nozzle housing, and chamber for supplying secondary air . The end part of the fuel-supplying needle is shaped into a cone with an inclination of 3-4° to the housing of the nozzle and projects out of the narrow part of the nozzle by 0.6-1.5 mm. The passage for supply of oxygen is connected with the system for supplying overheated steam.

EFFECT: reduced flow rate of fuel.

2 dwg

Description

The proposed technical solution relates to designs of rotary kilns used in the chemical, metallurgical, cement and other industries, and is aimed at improving the fuel combustion unit.

It is known that gas combustion is a reaction of oxidation of a combustible gas by atmospheric oxygen, which occurs at the interface between the gas and air in a layer called the flame front, only a few tenths of a millimeter thick. The flame front covers a stream of gas from all sides and therefore it seems to be a continuous torch. Intense combustion occurs only in the turbulent part of the jet, where the gas mixes well with air. This is the main combustion zone. To burn gaseous fuels, there are many devices whose designs are, to one degree or another, aimed at increasing the efficiency of fuel combustion, which also leads to a decrease in the content of harmful emissions in the combustion products.

A device for burning fuel in a rotary kiln according to A.S. USSR No. 1179073 (MKI F 27 B 7/36), which contains the central and outer pipes mounted coaxially and connected respectively to the sources of fuel and air, and also contains a mixing chamber equipped with a flow turbulator in the form of an elastic plate, which is mounted coaxially the central pipe and is equipped with a screen mounted on it at an angle of 50-80 °.

According to this invention, the flow of gaseous fuel flowing through the Central channel at the outlet encounters an obstacle in the form of a screen mounted at an angle on an elastic plate. Under the influence of the gas flow, the plate deviates, however, due to the elasticity of the plate tends to occupy its original position. As a result of the interaction of the elastic forces of the plate and the gas flow supplied under a certain excess pressure, the plate begins to vibrate intensively. The presence of vibration ensures efficient mixing of fuel with air. With all the advantages, this device has a drawback, namely: at high temperatures, the service life of such a turbulator is insignificant due to the loss of elasticity of the plate.

Also known nozzle by A.S. USSR No. 1229516, MKI F 23 D 11/34 (for official use), which contains a housing with an output nozzle and a locking needle mounted on its axis in the centering support, equipped with an axial vibration drive. Axial vibration is provided by a system of additional structural elements.

The disadvantages of this nozzle design are its complexity and, as a consequence, the high complexity in the manufacture and maintenance.

The closest solution in its technical essence and the achieved result to the proposed device for burning liquid fuel is the "Device for burning liquid fuel" according to the patent of the Russian Federation for utility model No. 11866 (F 23 D 17/00).

-й формы, цилиндрическая часть которой расположена в зоне конусной выемки выходного сопла и установлена с зазором относительно ее.According to the well-known patent, a device for burning liquid fuel contains a nozzle body with an output nozzle, inside which a fuel supply needle is installed coaxially to it, a channel for supplying primary air formed by the outer surface of the fuel supply needle and the inner surface of the nozzle body, the secondary air supply chamber with the nozzle body installed therein , the output nozzle of the nozzle body is made in the form of a conical recess with an angle of inclination of the generating surface to the axis of the nozzle body at 25-35 °, and the fuel supply needle filled with the possibility of moving it relative to the output nozzle, and the end of the fuel supply needle from the side of the output nozzle is made

-th form, the cylindrical part of which is located in the zone of the conical recess of the outlet nozzle and is installed with a gap relative to it.

A disadvantage of the known device is the insufficiently high efficiency of fuel combustion.

The objective of the invention is to increase the efficiency of fuel combustion and, as a consequence, reduce its consumption.

The technical result of the invention is to increase the length and volume of the flame during operation of the device in a rotary kiln.

The technical result is achieved in that in a device for burning fuel in a rotary kiln containing a nozzle body with an output nozzle made in the form of a conical recess with an angle of inclination of the forming surface to the axis of the nozzle body at 25-30 °, a fuel supply needle located in the cone recess area the output nozzle with the possibility of moving it relative to the output nozzle and installed with a gap relative to it, the channel for supplying the oxidizer formed by the outer surface of the fuel supply needle and the inner surface the nozzle nozzle, the secondary air supply chamber, the end part of the fuel supply needle is made conical with an angle of inclination of 3 ÷ 4 ° relative to the axis of the nozzle body and is extended beyond the narrow part of the nozzle by 0.6 ÷ 1.5 mm, and the channel for supplying the oxidizer is connected to the system supply of superheated steam.

Briefly, the technical essence is explained as follows.

To increase the length and volume of the combustion torch at the maximum efficiency of fuel combustion, it was proposed to create a maximum vacuum at the end of the needle, which allows for accelerated movement of the combustible mixture escaping from the outlet nozzle.

Comparison of the proposed technical solution with the prototype revealed a number of distinctive features:

- execution of the end part of the fuel supply needle conical with an inclination angle of 3 ÷ 4 ° relative to the axis of the nozzle body;

- the removal of the end of the fuel supply needle beyond the narrow part of the nozzle by 0.6-1.5 mm;

- connection of the channel for supplying the oxidizing agent to the superheated steam supply system.

In the distinctive part of the formula for the prototype contains a sign - "... a needle with the ability to move relative to the output nozzle ...", and therefore a sign of the proposed technical solution "... the removal of the end of the fuel supply needle outside the narrow part of the nozzle by 0, 6-1.5 mm ... "may seem known, but only if this feature is considered separately from the claimed combination of features. This feature is inextricably linked with the second distinguishing feature - "... the execution of the end of the needle conical with an inclination angle of 3 ÷ 4 ° relative to the axis of the nozzle body". The combination of these features allows us to conclude that the proposed solution meets the criteria of the invention of "novelty."

To compare the proposed solution with other well-known solutions in this and related fields, a search was carried out in patent and scientific literature.

In the search process, it was found that superheated steam is used as an oxidizing agent, which is fed into the channel for supplying the oxidizing agent.

Other technical solutions reflected in the characterizing part of the claims were not found.

Thus, the combination of features, both known, stated in the restrictive part of the formula, and unknowns, declared in the distinctive part of the claims, allows to obtain a technical and economic result of a higher level in comparison with known solutions, namely:

- reduce coke fumes during its calcination by 1.5-2%;

- reduce fuel oil consumption by 12%;

- reduce harmful emissions into the atmosphere.

Thus, we can conclude that the claimed object meets the criteria of the invention - "inventive step".

Industrial tests were conducted at the Irkutsk aluminum plant on a rotary kiln for coke calcination, which confirmed the high efficiency of the device for burning fuel.

Figure 1 shows a General view of a device for burning fuel in a rotary kiln (in section), figure 2 is a fragment of a device for burning fuel (with magnification).

The device includes an air supply chamber 1, inside of which the nozzle body 2 with an outlet nozzle 3 is mounted. Inside the nozzle body 2 and a fuel supply needle 4 is installed coaxially thereto. A feed channel 7 is formed between the outer surface 5 of the needle 4 and the inner surface 6 of the nozzle body 2. superheated steam.

The output nozzle 3 of the nozzle body 2 has a tapered recess 8 with an inclination angle of the generatrix of 25-35 ° to the axis of the nozzle body 2, and the end part 9 of the fuel supply needle 4 is conical with an angle of inclination of 3-4 ° relative to the axis of the nozzle body 2 and moved outside narrow part of nozzle 3 by 0.6-1.5 mm. In addition, the fuel supply needle 4 is provided with the possibility of its movement relative to the output nozzle 3 and has, for example, a threaded connection 10. A device for burning fuel is installed in the hot head of a rotary kiln 11.

A device for burning fuel in a rotary kiln operates as follows.

Liquid fuel (fuel oil) with a temperature of 80-90 ° С under a pressure of 5 atm (500 kPa) is supplied through a fuel supply needle 4, superheated steam is supplied through a channel 7 at the same pressure of 500 kPa, and air is supplied through a chamber 1. The amount of superheated steam supplied for combustion is controlled by changing the position of the fuel supply needle 4 relative to the output nozzle 3. The fuel supply needle moves axially due to the threaded connection 10. In this case, as the end part 9 of the needle 4 approaches the narrow part of the output nozzle 3, the supply of superheated steam decreases , when deleted - increases.

In the course of lengthy pilot tests of a device for burning fuel in relation to rotary kilns, the shape, design parameters and location of the end part 9 of the fuel supply needle 4 relative to the outlet nozzle 3 were experimentally determined. Performing the end part of the needle 9 with an angle of inclination relative to the axis of the nozzle body 3-4 ° and moving it outside the narrow part of the nozzle 3 by 0.6-1.5 mm ensures maximum turbulization of the fuel and oxidizer (mixing) in the zone of the nozzle 3. As a result, thinly leaves the nozzle dispersed fuel mixture, which ensures high combustion efficiency.

Claims (1)

A device for burning fuel in a rotary kiln, comprising a nozzle body with an output nozzle made in the form of a conical recess with an angle of inclination of the forming surface to the axis of the nozzle body 25-35 °, a fuel supply needle located in the zone of the conical recess of the output nozzle with the possibility of moving it relative to the output nozzles and a gap set relative to the nozzle, an oxidizer feed channel formed by the outer surface of the fuel supply needle and the inner surface of the nozzle body, the secondary feed chamber air, characterized in that the end part of the fuel supply needle is made conical with an angle of inclination of 3-4 ° relative to the axis of the nozzle body and is extended outside the narrow part of the nozzle by 0.6-1.5 mm, and the channel for feeding the oxidizer is connected to the supply system of the superheated couple.

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