RU2452895C2 - Device to burn lump solid fuel in pulsating flow - Google Patents

Abstract

FIELD: power engineering.

SUBSTANCE: device to burn lump solid fuel in a pulsating flow comprising a vertical shaft, a layer of burnt fuel, a pipe installed in a shaft, the section of which is smaller than the shaft section, a coolant flow controller, a temperature sensor, the shaft comprises one horizontal fire grate and two hoppers combined with ashpits and arranged oppositely to each other, a system of continuous charging of solid fuel of pushing type, a pipe, the upper part of which performs a function of a heat exchanger, a catcher of mechanical particles.

EFFECT: invention makes it possible to reduce content of hazardous emissions into atmosphere, to reduce generation of soot on cold walls of a heat exchange pipe.

2 dwg

Description

The invention relates to furnaces of a mine type for the layered burning of lump fuel and can be used in heat power plants, gasification chambers for the chemical industry, in incinerator mini-plants.

According to the main author’s certificate No. 556274, a device for burning lumpy solid fuel in a pulsating flow is known, comprising a vertical shaft with two parallel horizontal grate grids, a layer of fuel placed between them and a pipe installed above the upper grid in the shaft, the cross section of which is no more than the section of the shaft, than 4 times.

The disadvantage of this device is the occurrence of periodically repeated intense and weakly intense oscillations, leading to deterioration of combustion. In addition, the upper grate has a short service life due to its location in the high temperature zone.

Also known is the device adopted as a prototype, according to the copyright certificate No. 1008571 of March 30, 83, bull. No. 12, which includes a shaft, a pipe, two grates, the upper grate is made of a cooled heat exchanger pipe, a hopper, an ash pan, a coolant flow controller, and a temperature sensor.

The main disadvantage of this device should be attributed to poor environmental performance in gas emissions associated with soot formation on the cold walls of the heat exchanger pipe.

A device is proposed for burning lumpy solid fuel in a pulsating flow, comprising a vertical shaft, a layer of combustible fuel, a pipe installed in the shaft, the cross section of which is smaller than the section of the shaft, a flow rate regulator, a temperature sensor, characterized in that the shaft contains one horizontally arranged grate and two bunkers combined with ash pans and located opposite each other, a system of continuous loading of solid fuel of a pushing type, a pipe, the upper part of which performs the function tion of the heat exchanger, trap of mechanical particles. Moreover, in a laboratory setup created and tested by the applicant in an acoustic laboratory, the most effective results were obtained with a ratio of shaft and pipe sizes of not more than 4 times.

The proposed device allows you to maintain a stable mode of self-oscillation by maintaining the flow rate of air in the mine within specified limits. This is achieved by controlling the temperature of the pipe walls by changing the flow rate of the coolant circulating through the annular heat exchanger, since the pipe draft is highly dependent on the temperature of the pipe wall. The flame torch does not come into contact with the cold walls of the heat exchanger, which prevents the formation of soot. By vertically moving the grill, which is provided in the prototype, soot formation can be prevented. However, flame stabilization is impaired. The upper grate is designed to provide stabilization of combustion and uniform distribution of flame over the entire area of the grate. The conditions for stabilization of the flame and uniform distribution of heat along the grate in this device are fulfilled by supplying lumpy solid fuel to the grate in continuous operation simultaneously from both sides. Combustion processes (ignition, evolution of combustible gases and their combustion, coke burning, ash formation) occur simultaneously over the entire area of the grate, thereby ensuring uniform heat generation throughout the grate. In the prototype, lump fuel is supplied on one side, and it ignites only as it approaches the center of the grate. The initial grate section with such a lump fuel supply scheme will always generate less heat compared to other sections. The upper grate ensures smooth heat dissipation. During combustion, lumpy solid fuel from the gas stream is subjected to intense mechanical and thermal stresses. This leads to the destruction of pieces of burning fuel and partial entrainment of mechanical particles.

Despite the fact that in a pulsating gas flow, where nodes and pressure antinodes are present, coarsening of particles is often observed (in the future, these particles fall down due to gravitational forces), there is a need to clean gas emissions from mechanical impurities. In the proposed device, this problem is solved by a trap of mechanical particles.

To clarify the invention in figure 1. A diagram of a device for burning lumpy solid fuel in a pulsating flow is shown. Figure 2 shows a diagram of the supply of lump fuel to the grate 1.

The device includes: a shaft 4, in which the pipe 7 is coaxially located. In the shaft there is a horizontal grate 1, which performs the function of a grate. Two hoppers 8 with ash pans are attached to the shaft from two sides opposite to each other 2. Both hoppers contain loading devices 9. In the shaft, an ignition device 11 is located under the grate. The pipe is made in the form of a tubular heat exchanger 5 with a flow rate regulator 13. In the upper part the pipe is a temperature sensor 12 and a trap 6 of mechanical particles.

The device operates as follows. Lump solid fuel 3 is fed by means of loading devices 9 to the horizontal grate 1 and is ignited by the device 11. Combustion products rise upward through the pipe 7. Air is supplied to the combustion zone in two directions: through the annular gap formed by the shaft and the pipe; from the bottom of the shaft. At the initial moment, before the ignition of lumpy solid fuel, the required thermal energy in the device is provided due to the operation of the ignition device 11. In the device, longitudinal self-oscillations are excited. After ignition of lumpy solid fuel 3, the ignition device 11 is turned off. In the future, the pulsations are maintained due to the heat generated during the burning of solid fuel 3. On the horizontal grate 1 another batch of fuel 3 loading devices pushing type 9 is supplied simultaneously from both sides (Figure 2). The continuous supply of lump fuel 3 is organized in such a way that uniform burning is constantly ensured on the horizontal grate 1. This achieves stable self-oscillations in the acoustic tract. With an excessive increase in convective gas flow in the pipe (this is indicated by a temperature sensor 12), its walls must be cooled. The pipe walls are cooled to the required temperature by the circulation of the heat carrier, the speed of which is controlled by the flow regulator 13. Water can be used as the heat carrier. Cold water is supplied to the upper pipe, hot water is discharged through the lower pipe.

Thus, the proposed device provides a stable self-oscillating process, increases the reliability of the horizontal grate, prevents soot formation and entrainment of mechanical particles into the environment. The amplitude of the acoustic pressure pulsation in the device (in pipe 7) was measured by the applicant by means of the MIC-200 measuring complex and is about 160 dB.

At a distance of 1 meter from the device, the sound pressure level was 110 dB.

The claimed technical solution meets the criterion of "novelty" presented to the invention, because the claimed combination of features is not known from the analyzed prior art.

The claimed technical solution meets the criterion of "inventive step" for inventions, because the claimed combination of features and the achieved technical results are due to the fact that the claimed technical solution ensures the creation of a stable self-oscillating process without the influence of additional devices (for example: draft-blowing devices), which is evidence of compliance of the claimed solution with this criterion.

The claimed technical solution meets the criterion of "industrial applicability" to the invention, because The claimed technical solution is implemented in a pilot sample using conventional materials and known technologies.

Claims (1)

A device for burning lumpy solid fuel in a pulsating flow, containing a vertical shaft, a layer of combustible fuel, a pipe installed in the shaft, the cross section of which is smaller than the section of the shaft, a flow rate regulator, a temperature sensor, characterized in that the shaft contains one horizontally arranged grate and two bunkers combined with ashpits and located opposite each other, a system of continuous loading of solid fuel of a pushing type, a pipe, the upper part of which performs the function of heat transfer Nick, a trap of mechanical particles.

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