RU2244211C1 - Low-temperature swirling-type furnace - Google Patents

Abstract

FIELD: chamber-type burning of fuel; industrial and power-generating boilers.

SUBSTANCE: proposed swirling-type furnace has burners and under-grate blast nozzles mounted on front baffle wall at downward inclination and directed tangentially relative to arbitrary body at horizontal; axis of rotation; under-grade blast nozzles are mounted under lower bend of front baffle wall; top blast nozzles are mounted on rear baffle wall and are also tangentially directed towards arbitrary body of revolution. Top blast nozzles are grouped and are oriented to respective burners. Under-grate blast nozzles are made in form of ejectors and are mounted in bins formed by means of brickwork and/or baffle walls in dry-bottom ash hopper with at least one fire grate; fire grate is cooled with water and is provided with rabbling plate.

EFFECT: enhanced economical efficiency.

4 cl, 2 dwg

Description

The invention relates to the organization of chamber combustion of fuel and can be used in industrial and energy boilers during their reconstruction and the development of new boiler and furnace equipment.

Known used in the energy chamber furnace with an angular arrangement of pulverized coal or gas-oil burners [1, figure 10, 11]. In this case, slotted burners with a simple construction can be used. A vortex with a vertical axis of rotation is created in the furnace, providing good burning of combustibles and stable ignition.

The disadvantages of such a furnace are:

- a complex system of wiring the fuel and blast supply paths, since they need to be distributed with redundant paths along the entire perimeter of the furnace;

- inefficient use of the lower part of the furnace screens, since torch torches are located in its upper part, respectively, to ensure the required temperature level at the outlet of the furnace, an increase in its size is required.

Of the known technical solutions, the closest in technical essence to the claimed device, selected as a prototype, is a vortex low-temperature furnace [2, Fig. 22], containing direct-flow burners located with an inclination downward on the front screen and installed opposite the bend of the back screen of the lower blast nozzle . The jets of the burners and the lower blast are directed tangentially to the conditional body with a horizontal axis of rotation and, acting in pair, create a vortex that fills the cold funnel of the furnace. In this case, the lower part of the furnace screens is included in the active heat transfer, the temperature of the furnace process and the emission of harmful nitrogen oxides, sublimation of ash and slagging of the furnace screens are reduced.

The disadvantage of the prototype is the low efficiency associated with the mechanical underburning of fuel in failure and entrainment, since the combustion chamber does not organize the retention and afterburning of entrainment and failure, as well as increased excess air, since the introduction of blast does not ensure uniform redistribution of fuel and air.

Reduced profitability due to ablation and increased excess air is associated with the aerodynamics of the furnace. The air-fuel mixture in the prototype flows out of the burners, passes through the furnace volume, flows to the rear screen and is divided into two streams. The flow, [2, Fig. 22], rushing down into a cold funnel, has an increased residence time and good conditions for fuel burnout. However, the upward flow of the air-fuel mixture, without stopping, leaves the furnace and does not have time to burn out even with increased excess air. It is the upstream flow that requires increased excess air, creates increased underburning of fuel and reduces the efficiency of the furnace.

The objective of the present invention is to increase the efficiency of the furnace. The task is achieved in that in a vortex low-temperature furnace containing burners and nozzles of the lower blast located on the front screen with a downward inclination, directed tangentially to a conditional body with a horizontal axis of rotation, according to the invention, the lower blast nozzles are installed under the lower bend of the front screen, and on the rear The screen contains nozzles of the upper blast.

Additionally, the nozzles of the upper blast can be divided into groups according to the number of burners and in plan are oriented to the corresponding burners.

Also, the lower blast nozzles can be made in the form of ejectors and installed in bunkers formed by lining and / or screens in a cold funnel of the furnace. In addition, in a cold funnel for afterburning and conclusion of the failure, at least one water-cooled mechanized grate with a screwing bar can be located.

In the proposed furnace, in comparison with the prototype, the direction of rotation of the vortex changes. The air-fuel mixture, with the entire flow moving first down, is directed upward by the lower blast, rises along the rear screen and is deflected by the upper blast towards the burners, forming a vortex. This increases the path, residence time and fuel burn efficiency with reduced excess air.

The lower blast maintains large particles in the flow, and the upper blast keeps ablation. Consistent mixing of the air-fuel mixture with the lower and upper blast creates a uniform redistribution of fuel and air. The mechanical underburning with a dip is reduced by collecting in the bunkers and returning large particles of the dip to the furnace with ejectors of the lower blast or afterburning the dip on a mechanized grate. Thus, in the proposed furnace, with a minimum excess of air, the afterburning of the failure, as well as the retention and afterburning of the entrainment, are provided.

Figure 1 shows a vertical AA section of the proposed vortex low-temperature furnace, and figure 2 is a horizontal section BB performing coordinated orientation of the groups of nozzles of the upper blast with burners.

The low-temperature vortex furnace 1 is formed by the front 2, rear 3 and side 4 screens of the boiler. Burners 5 are located on the front screen 2 with an inclination downward, and nozzles 6 of the lower blast are located under its lower bend. On the rear screen 3 there are nozzles 7 of the upper blast, which are divided into groups (according to the number of burners 5) and in the plan (figure 2) nozzles 7 of the upper blast in each group are oriented to the corresponding burners 5.

Burners 5 are connected by fuel feeders 8 to fuel hopper 9. Air ducts 10 of nozzle 6, 7 and burner 5 are connected to fan 11. All nozzles and burners are directed tangentially to conditional body 12 with a horizontal axis of rotation. This in the furnace 1 ensures the vortex movement of the burning stream, the deviation of the stream leaving the furnace to the front 2 screen, uniform, sequential redistribution and mixing of burning particles with the air of the lower and upper blasting, afterburning, and burning of fuel with a minimal excess of air.

The nozzles of the lower blast 6 can be made in the form of ejectors 13 installed in the hoppers 14 formed in the cold funnel of the furnace 1 formed by means of wiring and / or screens 2-4 in the cold funnel 1. At least one water-cooled one can be located the grate 15 with a screwing bar 16 connected to the ash removal system 17 and the duct 10 to the fan 11. By collecting in the bins 14 and returning large particles of the hole into the furnace 1 by ejectors 13 and / or afterburning the hole on the mechanized grate 15 mechanical removal of unburned carbon from the fuel failure.

In addition to the screens, the firebox may include heating medium heating surfaces 18, a smoke exhauster, and other necessary elements.

The proposed vortex low-temperature furnace operates as follows. Coal from the hopper 9 is dosed by the feeders 8 into the burners 5 and supplied with the primary air to the furnace 1. In the furnace 1, it ignites, mixes with the flows of the lower and upper blast, pumped through the nozzles 6, 7 through the air ducts 10 by the fan 11 and burns out. The combustion products give off heat to the screens 2, 3, 4 and to the heating medium surfaces 75 and, after cooling, are removed from the installation.

Due to the fact that the nozzles 6, 7 and the burner 5 are directed tangentially to the conditional body 12 with a horizontal axis of rotation, a swirling motion of the burning stream is formed in the furnace 1. This ensures a uniform, sequential redistribution and mixing of burning particles with the air of the lower and upper blast, afterburning of entrainment and burning of fuel with a minimum excess of air. The nozzles 7 of the upper blast deflect the rising flow of gases and entrainment along the rear screen 3 to the front screen 2 and burners 5, supporting the ignition of fresh fuel in the burners 5, filling and involving the upper corner at the front of the furnace 1 in the active combustion process. The grouping of the nozzles 7 and the supply of the upper blast and the burning stream directly to the corresponding burners 5 enhances the ignition of fresh fuel, the retention and afterburning of entrainment.

Vortex flow and filling the furnace with a burning stream provide increased efficiency of heat removal to the screens 2-4 and a low-temperature combustion process.

In the proposed furnace, as in the prototype [2, Fig. 22], combustion of not only dust but also crushed fuel can be organized, with the retention of large particles in a vortex due to lower blasting. The implementation of the nozzles 6 in the form of ejectors 13 installed in the hoppers 14 provides for the capture, ejection and retention of large particles in the furnace with lower costs of the lower blast. In addition, the afterburning of the failure is carried out on a mechanized grate 15 with the removal of focal residues in the ash removal system 17 with a screwing strap 16. This ensures the elimination of mechanical underburning with a fuel failure. Water cooling of the grate 15 supports its reliable operation.

The use of the proposed vortex low-temperature furnace allows to increase efficiency compared to the prototype [2, Fig. 22]. In the prototype [2, clause 4.5], due to the direct removal of part of the dusty air stream along the rear screen, increased excess air is required and the combustion of fuel is accompanied by a significant mechanical underburning.

Literature

1. High power boilers. Directory. - M.: NIIINFORMTYAZHMASH, 1970, Fig. 10, 11.

2. Kotler V.R. Special furnaces of power boilers. - M .: Energoatomizdat, 1990, Fig. 22.

Claims (4)

1. Vortex low-temperature furnace, containing burners and nozzles of the lower blast located on the front screen with a downward inclination, tangentially directed to a conditional body with a horizontal axis of rotation, characterized in that the lower blast nozzles are installed under the lower bend of the front screen and the nozzles are located on the rear screen upper blast, also directed tangentially to the conditional body of rotation. 2. The furnace according to claim 1, characterized in that the nozzles of the upper blast are grouped and oriented in plan to the respective burners. 3. The furnace according to claim 1, characterized in that the nozzles of the lower blast are made in the form of ejectors and are installed in bunkers formed by means of lining and / or screens in a cold funnel of the furnace. 4. The furnace according to claim 1, characterized in that at least one grate with a screwing bar is located in a cold funnel.

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