RU49602U1 - SMALL POWER CAST IRON BOILER WITH A HEAT OF A HIGH-TEMPERATURE BOILER LAYER - Google Patents

Abstract

The utility model relates to the field of heat power engineering. The boiler consists of a mechanical furnace device in the form of a narrow, mobile, inclined grate grate backward for burning fuel in a high-temperature fluidized bed, heating surfaces, fuel feeder, hopper and ejector return ablation. Fuel is supplied by a scraper feeder to an inclined plate and further to the furnace. The heating surfaces consist of cast-iron sections, steel gas-tight front and rear screens, a convective beam and a cooling panel located along the grate sheet. The cooling panel is made of a series of pipes, placed one above the other, and has a U-shaped layout in plan. The combustion products from the combustion chamber pass through the channels inside the cast-iron sections to the side inclined flues located on both sides of the boiler, enter the entrainment return hopper with an ejector, where unburned particles of fuel and fly ash are separated and, passing through a convective beam, are removed from the boiler. A two-stage air supply is used. Part of the air goes under the grate through the blast zones of the primary air, and the other into the superlayer space through the nozzles of the secondary blast.

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" [l]. The furnace consists of a narrow, movable grate, inclined to the horizon by 10-15 °. Air for fluidization 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 "E5-D2" [3]. It includes a manual maintenance furnace with a fixed grate, heating surfaces, consisting of packages of cast-iron sections. 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 the mechanization of furnace processes in the boiler and the ability to burn low-grade coals with a high efficiency and improved environmental performance.

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 for 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. Due to the active mixing of coal particles, intensive washing with air, quick 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. A convective beam is installed behind the combustion chamber, which is included in the boiler circulation circuit and is an additional heating surface. This allows you to reduce heat loss with flue gases and increase efficiency boiler.

3. Under the convective beam, an ablation return hopper with an ejector is installed, into which the flue gases come from inclined flues. This makes it possible to sediment unburned particles of fuel and fly ash removed from the furnace in the entrainment return bunker and, with the help of an ejector, return them to the combustion chamber for afterburning, which contributes to an increase in the efficiency of fuel burnout and reduction of losses from mechanical incompleteness of combustion, transfer

parts of unburned particles of fuel and fly ash into slag and reduction of emissions of solid particles with flue gases.

4. 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), which 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 oxygen in the active combustion zone reduces NO _x emissions and improves the environmental performance of the boiler.

5. Fuel is supplied by a scraper feeder to an inclined plate, from where it enters the furnace under the influence of gravity. The mechanization of fuel supply eliminates heavy physical labor and reduces the number of staff.

6. In the combustion chamber along the grate, an additional heating surface (cooling panel) is installed, 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 scraped fuel feeder, an ablation return hopper with an ejector. The main technological element of the firebox is a narrow, inclined to the horizontal, movable grate (1). Device

also includes a frame with an air box inside it (2), divided into primary air blow zones, a drive (3) and driven (4) shafts with sprockets, a grill drive (5), as well as lateral and transverse (interzone) seals . To control the temperature level in the fluidized bed, cooling panels (6) are installed.

The combustion chamber is limited on the sides and on top by two packages of cast-iron sections (7), a front screen (8) with one and a rear screen (9) on the other side. In the upper part of the front screen there is a window for organizing fuel supply (10). Fuel is supplied to the grate from the hopper (17) via an inclined heat (11) using a scraper feeder (18).

The following gas movement pattern is organized in the boiler. Gases rise from the grate (1) to the upper part of the combustion chamber, go around the edges of the partitions of the cast-iron sections (7), pass down a series of parallel channels between the sections in the right and left packages and then enter the side inclined flues (12). Behind the lower part of the rear screen (9), gases exit the side ducts (12) and turn into the central part and into the ablation return hopper (13). A sharp turn of the gases allows the unburnt particles of fuel and fly ash removed from the furnace to be deposited in the ablation recovery hopper (13) and returned to the afterburning chamber with the help of an ejector (14).

The convective beam (15) is located immediately behind the combustion chamber and is separated from it by the rear screen of the furnace (9). The side walls of the convective beam are partially gas-tight with the formation of windows (16) in the upper part. In the front wall, directly above the grate, there is a repair hole (19) for servicing the furnace systems.

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. St. Petersburg: VISI, 1995, pp. 273-276.

Claims (1)

Coal burning boiler, consisting of a furnace device, cast-iron heating surfaces, characterized in that the furnace device is made in the form of a narrow, movable, inclined to the horizon grate backstop with blast zones of primary air, with a scraped fuel feeder and an inclined stove, secondary nozzles blasting system, hopper and ablation return ejector, the boiler unit is supplemented by steel gas-tight front and rear screens, convective heating surfaces and a cooling panel located along the blade and the grate of the return stroke, the side flues are made in the form of channels inclined to the horizon.