RU68652U1 - DUST-BURNER WITH AERODYNAMIC AEROSMIX FLOW CONVERTER - Google Patents

Abstract

The utility model relates to a power system and can be used as a coal-dust burner for boilers of thermal power plants and industrial boiler houses. The achieved result of the utility model is to simplify the design, increase the ignition rate and the completeness of fuel combustion during the two-stage combustion of coal dust while maintaining a reduced yield of fuel nitrogen oxides. This is ensured by the fact that the aerodynamic transducer installed in the annular channel for supplying the air mixture behind the swirl along the air mixture is made in the form of at least three longitudinal radial partitions uniformly spaced around the circumference of the annular channel and forming a system of direct-flow parallel channels. 1 unc., 2 ext. P. f-ly, 2 ill.

Description

The utility model relates to a power system and can be used as a coal-dust burner for boilers of thermal power plants and industrial boiler houses.

A known vortex dust-coal burner, which is accepted as the closest analogue of the utility model, contains a central channel for accommodating an ignition device, annular channels sequentially arranged around the central channel for supplying air mixture and secondary air with blade swirls in each channel and installed in the channel for supplying air mixture for swirl along the aerosol mixture aerodynamic flow transducer [1]. The aerodynamic transducer according to [1] is made in the form of a confuser-cylindrical insert and a confuser-diffuser nozzle that are installed sequentially along the flow stream, which makes it possible to reduce the formation of fuel nitrogen oxides as a result of the optimal distribution of the air mixture components over the cross section of the annular jet at the outlet of the burner. The disadvantages of the burner [1] include the structural complexity of the technical solution, as well as the worsened conditions for the implementation of the first stage (with a lack of oxygen) of the two-stage process of burning coal dust, resulting from the displacement by the central concentrated dust stream of high-temperature paraxial recirculation gases moving towards it.

The achieved result of the utility model is to simplify the design, increase the ignition rate and the completeness of fuel combustion during the two-stage combustion of coal dust while maintaining a reduced yield of fuel nitrogen oxides.

This is ensured by the fact that in a vortex pulverized coal burner containing a central channel for accommodating a kindling device,

consecutively located around the central channel, annular channels for supplying the air mixture and secondary air with scapular swirls in each channel and an aerodynamic flow converter installed in the channel for supplying the air mixture behind the swirl along the air mixture, the aerodynamic converter is made in the form of at least three longitudinal radial partitions evenly spaced around the circumference of the annular channel and forming a system of direct-flow parallel channels.

Moreover, the recommended optimal number of partitions is 4–8, and the optimal length of each partition is 1.5–2.5 D, where D is the larger of the two inner diameters of the annular channel.

Figure 1 shows a pulverized coal burner according to a utility model in longitudinal section; figure 2 is a view along arrow In figure 1.

The burner contains a central channel 1 for accommodating a kindling device, which in this particular case is a fuel oil nozzle 2, with a pipe 3 for supplying part of the air to the channel (central air). Around the central channel 1, an annular channel 4 for supplying air mixtures and two annular channels 5 and 6 for supplying secondary air are concentrically arranged coaxially with it. Channels 4, 5, 6 are equipped with inlet nozzles 7, 8, 9. In each channel 1, 4, 5, 6, blade swirls are installed, respectively, 10, 11, 12, 13 (Fig. 1). In this case, the swirlers in all channels except channel 4 for supplying air mixtures are installed at their outlet sections, and the swirler 11 in channel 4 is installed at the inlet section of this channel. An aerodynamic flow transducer is installed behind the swirler 11 at the output section of the channel 4 for supplying the air mixture; in this example, it is made in the form of six longitudinal radial baffles 14 uniformly spaced around the circumference of the annular channel 4 and forming a system of direct-flow parallel channels 15 (Fig. 2) for the release of jets 16 dust flow. The length L of each partition (Fig. 1) is 1.5 ÷ 2.5 D, where D is the larger of the two inner diameters of the annular channel 4. Each partition 14 can be made

concave from the side of the oncoming swirling flow of the mixture. The burner is installed in the embrasure of the wall 17 of the combustion chamber.

Vortex pulverized coal burner according to a utility model operates as follows. First, fuel and air are supplied, respectively, to a kindling device (fuel oil burner 1) and pipe 3 of the central channel 1. Then, air mixture and secondary air are supplied through the supply pipes 7, 8, 9, respectively. All flows of air and air mixtures during forward movement along the corresponding channels are vortexed using scapular swirlers 10, 11, 12, 13. The swirling flow of air mixture in the outlet part of the channel 4 runs onto the radial partitions 14 (aerodynamic flow transducer). On each partition 14, when meeting with the oncoming flow of a swirling air mixture, a stream of coal dust depleted in air is concentrated. In the furnace space, these flows move rectilinearly and fall into the axial zone of recirculation of combustion products with a low oxygen content. At the same time, on the one hand, due to the direct-flow nature of the movement of dust jets, centrifugal forces do not discard coal particles to the inner surface of the secondary air flow, where oxygen is usually intensively mixed with flammable volatile fuels. This ensures a reduced yield of fuel nitrogen oxides. On the other hand, in comparison with [1], the burner, according to the utility model, due to the separation of a continuous stream of concentrated dust into separate jets with structural simplicity provides more favorable conditions for the efficient flow of the first stage of a two-stage fuel combustion process.

Information sources

1. Patent RU No. 2053442, 7 F23D 1/06, 1992.

Claims (3)

1. Vortex pulverized coal burner containing a central channel for accommodating the kindling device, successive circular channels around the central channel for supplying the air mixture and secondary air with blade swirlers in each channel and an aerodynamic transducer installed in the channel for supplying the air mixture behind the swirler along the air mixture flow, characterized in that the aerodynamic transducer is made in the form of at least three longitudinal radial partitions, uniformly aspolozhennyh annular channel around the circumference and forming parallel channels ramjet system. 2. Vortex pulverized coal burner according to claim 1, characterized in that the number of partitions is 4 ÷ 8. 3. Vortex pulverized coal burner according to claim 1 or 2, characterized in that the length of each partition is 1.5 ÷ 2.5 D, where D is the larger of the two inner diameters of the annular channel.