RU41838U1 - TWO DRUM BOILER OF SMALL POWER WITH A HEAT OF A HIGH-TEMPERATURE BOILING LAYER - Google Patents

Abstract

Coal burning boiler, consisting of a combustion device, heating surfaces including two drums, a convective tube bundle with a heat-resistant steel partition for horizontal turn of gases, a front, ceiling and two side radiation screens with collectors, a fuel feeder, characterized in that The furnace device is made in the form of a narrow, mobile, inclined grate backward grate for burning fuel in a high-temperature fluidized bed, a front, furnace and two side screens and made gas-tight, in a convective beam, two baffles made of heat-resistant metal were installed to turn the gases in a vertical plane and subsequently get unburned particles of fuel and fly ash in the gases into the flyback hopper with an ejector, the fuel is supplied by gravity using a mechanical feeder, air is supplied is carried out under the grate through the blast zones of primary air and into the superlayer space through nozzles of the secondary blast, in the combustion chamber along the floor a cooling panel is installed on the grill, which is included in the boiler circulation circuit.

Description

The utility model relates to the field of heat power engineering.

Known boiler with a furnace for burning solid fuel in a fluidized bed design "Ignifluid" [1]. The furnace consists of a narrow, movable grate, inclined to the horizon by 10-15 °. Air for the liquefaction of the layer is supplied through a grate from an air box, divided into sections, in each of which a predetermined pressure is maintained. Grid seals at the front and side walls of the combustion chamber are achieved by natural slag filling, which borders the fluidized bed and protects the furnaces from overheating. The system of pipes cooled by water located inside prevents slagging of the layer, holds backfill on each side of the grate and directs the flow of slag [2].

Known boiler unit E-1/9 [3]. It includes a manual service furnace, consisting of a grate with rotary grates, heating surfaces, consisting of two drums, a convective tube bundle, a front, ceiling and two radiation screens with collectors, a convective beam has a heat-resistant steel partition for turning gases into horizontal plane. Fuel is supplied manually by service personnel. The air required for combustion is supplied under the grate.

This analogue has several disadvantages:

- layered burning on a wide grate leads to large losses from mechanical underburning, does not allow the use of low-grade coals with high ash, moisture and a large number of fine fractions;

- all air is supplied under the grate, which increases the entrainment of solid particles of fuel and slag from the furnace;

- manual fuel supply is accompanied by heavy physical labor of maintenance personnel, as well as an increase in its quantity;

- layered combustion leads to an increased content in the exhaust gases of harmful oxides of nitrogen and sulfur, ash and soot particles.

The objective of the utility model is to improve the reliability of the design of the device, the possibility of burning low-grade coal, the exclusion of heavy physical labor of maintenance personnel, increasing the efficiency, increasing heat production and improving the environmental performance of the boiler.

This problem is solved due to the fact that:

1. To burn fuel, a mechanical furnace device is used in the form of a narrow, movable grate grate inclined to the horizon, which implements the technology of burning fuel in a high-temperature fluidized bed. According to this technology, the fuel layer is blown by an intense stream of air supplied from below through the grate. In this case, the fuel particles begin to mix intensively. Thanks to the active mixing of the coal particles, their intensive washing off with air, the rapid removal of the ash crust from the outer surface of the pieces of fuel, it is possible to burn the combustible mass up to 98%. This allows this boiler to work with high efficiency on low-grade coals with high ash content, humidity, low heat of combustion, a large number of small fractions.

2. In the convective part, two partitions of heat-resistant steel are installed for turning the gases in a vertical plane and an ablation return hopper with an ejector. This makes it possible to precipitate particles of flying ash and unburned fuel that have been carried away from the furnace in the flyback hopper and, with the help of an ejector, return them to the combustion chamber for afterburning. This increases the efficiency of fuel burnout, transfers part of unburned particles of fuel and fly ash to slag and reduces emissions of solid particles with flue gases.

3. A two-stage air supply is used. Air is directed under the grate through the blast zones of the primary air and into the superlayer space through the nozzles of the secondary blast. The air supplied to the superlayer space forms a screen (air surface) that prevents the entrainment of particles of dispersed material, which increases the efficiency of fuel combustion and reduces the loss of heat with entrainment. Reducing the amount of O ₂ in the active combustion zone reduces NO _x emissions and improves the environmental performance of the boiler.

4. Fuel is supplied by a mechanical feeder to the accelerating plate, from where it enters the furnace under the influence of gravitational forces. The mechanization of fuel supply eliminates heavy physical labor and reduces the number of staff.

5. In the combustion chamber along the grate, an additional heating surface (cooling panel) is installed, which is included in the boiler circulation circuit. The cooling panel is made of a series of pipes placed close to each other. Each pipe has a U-shaped layout in plan. An additional heating surface provides active control of the temperature level of the fluidized bed, prevents slagging of the grate, which ensures an increase in the efficiency of fuel combustion and an increase in heat output.

The proposed boiler design is not identified from the existing level of technology. This allows us to conclude that it meets the criterion of "novelty."

The proposed design of the boiler is illustrated by the drawing shown in figure 1. The boiler includes a mechanical furnace device, heating surfaces, a mechanical fuel feeder, an ablation return hopper with an ejector. The main technological element of the furnace is a narrow, horizontal, movable grate (7). The device also includes a frame with an air box (9) located inside it, divided into primary air blast zones, a grill drive, and also lateral and transverse (interzone) seals. The heating surfaces consist of two drums (1, 2), a convective tube bundle (6), gas-tight front, ceiling and two side screens (3) with collectors (4, 5) and a cooling panel (11).

In the convection beam, two partitions (14) made of heat-resistant metal are installed. A mechanical fuel feeder (13) and a fuel hopper (18) are installed at the front of the boiler. Under the convective beam there is an ablation return hopper (15) of unburned fuel particles and fly ash with an air ejector (16). Secondary blast nozzles (12) are brought into the combustion chamber volume.

The device operates as follows. The fuel is fed by a mechanical feeder (13) from the hopper (18) to the accelerating plate, acquires a certain speed and enters the active combustion zones in the initial part of the grate (8), where it warms up and burns in suspension over the canvas. The resulting slag, sticking together into large agglomerates, is lowered onto the grate (8) and removed from the boiler into the slag hopper (17).

The small unburnt and partially burnt particles carried out from the layer fall into the expanded part of the furnace, lose their speed and in most

their return from the zone of active combustion. Part of the air necessary for the combustion of fuel is supplied to the blast zones of primary air (9). The rest of the air enters the superlayer space through the nozzles of the secondary blast (12).

Flue gases exiting directly from the fluidized bed contain gaseous products of incomplete combustion and unburned solid particles of fuel. The streams of secondary air supplied towards each other, colliding, spread over the grate, burn the gases and prevent the removal of particles from the active combustion zone.

In order to reduce heat loss with mechanical underburning and to reduce solid emissions, an ablation recovery system is used. A baffle made of heat-resistant metal (14) in a convective beam (6) provides a 180 ° turn of flue gases and separation of unburned fuel particles and fly ash, which are deposited in the flyback hopper (15) and are returned to the ejector (16) to the active combustion zone of the combustion chamber, where unburned fuel particles are burned, and most of the fly ash is converted to slag.

The cooling panel (11) is installed along the grate (8). It is made of a series of pipes placed close to each other. Each pipe has a U-shaped layout in plan. The cooling panel, in addition to preventing slagging of the layer, holding backfill on each side of the grate, and directing the flow of slag, also provides an increase in the heat output of the boiler.

The above allows us to conclude that the criterion of "industrial use".

1. A. p. Baskakov and others. Boilers and furnaces with a fluidized bed. M .:

Energoatomizdat, 1995, p. 260.

2. A. p. Baskakov and others. Boilers and furnaces with a fluidized bed. M .:

Energoatomizdat, 1995, p. 263.

3. V.V. Somov. Boiler installations. S.-Pb .: VISI, 1995, pp. 176-177,240-241.

Claims (1)

Coal burning boiler, consisting of a combustion device, heating surfaces including two drums, a convective tube bundle with a heat-resistant steel partition for horizontal turn of gases, a front, ceiling and two side radiation screens with collectors, a fuel feeder, characterized in that The furnace device is made in the form of a narrow, mobile, inclined grate backward grate for burning fuel in a high-temperature fluidized bed, a front, furnace and two side screens and made gas-tight, in a convective beam, two baffles made of heat-resistant metal were installed to turn the gases in a vertical plane and subsequently get unburned particles of fuel and fly ash in the gases into the flyback hopper with an ejector, the fuel is supplied by gravity using a mechanical feeder, air is supplied is carried out under the grate through the blast zones of primary air and into the superlayer space through nozzles of the secondary blast, in the combustion chamber along the floor a cooling panel is installed on the grill, which is included in the boiler circulation circuit.