RU2403500C1 - Device for supply of gases into furnace - Google Patents

Abstract

FIELD: power engineering.

SUBSTANCE: device for supply of gases into furnace has flow path made of inlet confusor, rectilinear section and outlet diffuser, each section of flow path has rectangular section, at the same time in this outlet section of confusor, width relates to height as 6:1, and diffuser along width is separated into five curvilinear channels, in which one is arranged in device centre, and others are located symmetrically relative to it. Outlets of two side and two middle channels are arranged at the angle of 90° to outlet of central channel.

EFFECT: increased efficiency of fuel and air mixing and operational reliability by reduction of high-temperature effect at furnace walls.

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Description

The invention relates to a power system and can be used in devices for supplying gases to the furnace of boilers, furnaces in systems for recirculation of combustion products, step-by-step burning of fuel or sharp blast. It can also be used to supply gases in life support systems, in air curtains and other systems.

In boilers, a gas supply device is located on the back wall of the furnace against the burner, and combustion gases taken from a convective gas duct, or air heated to 250 ° C, and water vapor are used as supplied gases.

A device for supplying combustion products to the furnace of the boiler, the flow part of which has an input channel of rectangular cross-section, located vertically parallel to the axis of the furnace. The device is located on the back wall of the boiler, facing the burner located on the front wall, and at the same level as the burner in height of the firebox (B. And Reznik et al. Some design issues and the design of the Ep-640 / 140GM boiler unit for a 200 MW power unit. - M.: Power engineering, 1971, No. 3, p.2-7). The device is designed to increase the temperature of the gases at the outlet of the furnace by supplying a certain amount of combustion products from the convective gas duct back to the furnace.

The disadvantages of the known device are:

1. The lack of gas velocity in the output section of the device, since the flow part is made in the form of a rectangle of constant cross section, and as a result, the lack of range of the jet.

2. Overheating of the rear and side walls of the furnace and the destruction of the lining of the furnace in the region of the rear wall from the action of the temperature of the torch, since it is almost impossible to squeeze the torch out of the combustion products leaving the device.

3. Poor mixing of the combustion products, as the stream of combustion products from the device actually penetrates the torch through.

A device is known, the flowing part of which contains an inlet cylindrical confuser and a cylindrical channel of constant cross-section (V.M. Bryukhanov et al. Radiation gas heating. - L .: Nedra, 1989, p.20).

The disadvantages of the known device are:

1. Overheating of the rear and side walls of the furnace and the destruction of the lining of the furnace in the region of the rear wall from the action of the temperature of the torch, since it is practically impossible to squeeze the torch out of the combustion products leaving the device.

2. Poor mixing of the combustion products, as the stream from the device actually penetrates the torch through.

A device is known, the flow part of which contains an inlet conical confuser, an outlet conical diffuser (A.P. Kovalev et al. Steam generators. - M .: Energoatomizdat, 1985, p. 100).

The disadvantages of the known device are:

1. Insufficient gas velocity in the outlet section of the device, since in a diffuser having a large opening angle (about 90 °), the flow velocity is lost and, as a result, the range of the jet is absent.

2. The stream exiting the device practically does not squeeze the torch from the back wall of the furnace due to the fact that the gas stream is not localized.

3. Overheating of the side walls of the furnace, since it is almost impossible to squeeze the torch out with the gas stream leaving the device.

Closest to the claimed technical solution is a device whose flow part has an inlet conical confuser, a cylindrical channel and an output curved diffuser (V.M. Bryukhanov et al. Radiation gas heating. - L .: Nedra, 1989, p. 94).

The disadvantages of this device are:

1. Insufficient gas velocity in the outlet section, since the opening angle of the diffuser is large and, as a result, the small range of the jet with respect to portions of the rear wall that are at a remote distance from the center of the diffuser.

2. The area of squeezing the torch from the back wall in the center around the diffuser is small and is actually limited to two diameters of the diffuser in the maximum section.

3. A low degree of mixing of the stream of the supplied jet with the products of combustion of the torch, since the jet after the diffuser is very quickly extinguished, and the interaction occurs only on a short contact area between the torch and the supplied jet.

4. It is practically impossible to squeeze the torch from the side walls of the furnace to prevent them from overheating by the stream leaving the diffuser.

The task to which this technical solution is directed is to increase the efficiency of mixing fuel with gas and squeezing the torch from the back wall of the furnace.

The technical result is achieved by the fact that in the device for supplying gases to the furnace, having a flow part consisting of an inlet confuser, a rectilinear section and an outlet diffuser, each section of the flow part has a rectangular section, while in the outlet section of the confuser, the width refers to a height of 6: 1, and the diffuser is divided symmetrically in width into five curved channels with equal cross-sectional areas at the entrance to the diffuser, one of which is located in the center, and the other four are symmetrically in two channels on each side relative to the center. The outputs of the two side and two middle channels are located at an angle of 90 ° to the output of the central channel.

Figure 1 shows a General view of the proposed device for supplying gases to the furnace from the diffuser side, Figure 2 is a General view of the device with a cutout, Figure 3 is a side view of Figure 1, Figure 4 is a perspective view of the device.

The inventive device has a flowing part of a rectangular cross-section, consisting of an input confuser 1, a rectilinear portion of a constant section 2 and an output diffuser 3.

The flow part of the diffuser 3 consists of five channels: one central channel 4, two middle channels 5, each of which is located symmetrically with respect to the central channel and two side channels 6, each of which, like the middle channel, is located symmetrically with respect to the central channel. All channels have two side walls of a curved shape, and the other two have a flat shape. The outputs of the two side and two middle channels are located at an angle of 90 ° to the output of the central channel.

The device operates as follows.

Heated to 250 ° C air enters the confuser 1, in which its speed increases due to the narrowing of the channel. The use of rectilinear channel 2 allows to increase its flow coefficient. In the diffuser 3, as a result of a smooth decrease in air velocity, kinetic energy is converted into pressure energy of the air flow. The static air pressure along the diffuser 3 rises to the outlet cross section.

In the side channel 6, the air flow rotates at an angle of 90 ° to the original flow direction at the entrance to the diffuser and a slight decrease in speed. As a result of this, the air stream has a large range, which allows you to reach the side wall of the boiler and eliminate the flare of the torch on the side wall of the boiler.

In the middle channel 5, there is a greater decrease in the air flow rate, since the opening angle of the channel 5 is larger compared to the side channel 6. The stream from the middle channel 5 has a lower range compared to the stream exiting the channel 6, but much larger compared to the stream, emerging from the central channel 4. With the help of the jet from channel 5, the projection of the torch onto the rear wall of the furnace is eliminated.

The air flow rate at the outlet of the central channel 4 is low, but its static pressure is higher than the pressure of the products of combustion in the flare, and since the flows of air and products of combustion of the torch along the height of the furnace are carried out due to the vacuum created in the furnace by the exhaust fan, the vacuum of the exhaust fan affects stronger. In addition, in the cross section, the channel width is six times greater than the height, hence the torch is squeezed out over a large area from the back wall due to the static pressure of the air flow from the central channel 4, preventing its destruction.

An example of a specific design of the inventive device.

In the TGM-84A steam boiler with a steam capacity of 420 t / h with four powerful gas-oil burners installed in two tiers at elevations of 7 m and 11.5 m on the front wall, the back wall periodically collapsed due to high temperature with burning of the outer metal cladding from sheet steel 4 mm thick. The side walls in the area adjacent to the rear wall were also destroyed. There was a problem of weak overheating of the steam, since excess heat was removed from the torch in the furnace.

To eliminate these shortcomings, the proposed device was mounted on the rear wall, located opposite to the burner. The optimal location of the device is 1 m lower relative to the level of the burner and at an angle of 45 ° to its axis.

The device consists in the direction of air movement: from the confuser channel, the channel of constant cross-section and the diffuser channel.

Dimensions of the confuser channel at the outlet: horizontal width 360 mm and height 60 mm. The dimensions of the channel of constant cross section: horizontal width 360 mm and height 60 mm. The dimensions of the diffuser channel: length 210 mm, the width of the Central channel at the outlet 420 mm. The vertical opening angle of the diffuser channel is 36 °. The radii along the middle line of the bends: the lateral channel is about 90 mm, the middle channel is about 180 mm. Material - sheet steel 12HMF 4 mm thick.

Hot air enters the device in an amount of 7% of the total amount of air supplied to the burner.

The torch was squeezed from the side walls of the furnace and from the back wall of the furnace with increasing temperature of superheated steam in a convective superheater.

The advantages of the claimed device:

1. High selective air flow rate in the middle channels of the diffuser further increases the squeezing of the torch from the rear wall of the furnace.

2. In the center of the diffuser, the area of the squeezing of the torch from the back wall around increases due to the selected design parameters of the confuser, at which the width in the outlet section of the confuser is six times the height, which allows you to cover a large area of squeezing of the torch due to the movement of the combustion products of the torch and the air flow up the furnace . In this case, the area is limited by the width of the air flow leaving the central rectangular channel of the diffuser. In the claimed invention, the width of the diffuser exceeds the diameter in the known device with equal areas of a circle and a rectangle.

3. The high intensity of mixing of the combustion products, as the device has five air flows with clear boundaries between the speeds relative to each other.

4. The air flows coming from the side channels of the diffuser and having high speed and great range, the torch is squeezed from the side walls of the furnace, which prevents them from burning out.

Claims (1)

A device for supplying air to the furnace, having a flow part consisting of an inlet confuser, a rectilinear section and an outlet diffuser, characterized in that the flow parts of the inlet confuser and a rectilinear section have a rectangular section, while in the outlet section of the confuser, the width refers to a height of 6: 1, and the diffuser is divided in width into five curved channels with equal cross-sectional areas at the entrance to the diffuser, of which one is located in the center of the device, and the rest are symmetrical about it, when that the outputs of two side and two secondary channels disposed at an angle of 90 ° to the output of the center channel.

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