RU1778445C - Boiler - Google Patents

Abstract

Usage: in the chemical, metallurgical and other sectors of the national economy in which a fluidized bed is used. SUMMARY OF THE INVENTION: the walls of the fuel supply channel and its distribution device are located above the gas distribution grid and immersed in a fluidized bed. The switchgear is made in the form of a plate inclined to the horizon with holes fastened to the walls at a distance from the lower edges of the latter with the formation of an air cavity. The distance from the lower edges of the channel walls has a constant value along the channel length, and sections of the air cavity are formed by vertical partitions fastened to the channel walls under the plate. The invention improves the efficiency of burning solid fuel in fluidized bed boilers, solves the issue of uniform distribution of solid fuel (coal) over the cross section of the furnace. 1 s P. f-ly, 2 ill.

Description

The invention relates to a power system, can be used in the chemical, metallurgical and other industries of the national economy.

The various designs of fluidized bed boilers of the intermediate coolant are known, where coal is supplied by various pneumatic or mechanical spreaders. In this case, fuel is supplied by screws located on the sides of the furnace or through radially arranged nozzles attached to the annular channel, cup-shaped nozzles, nozzles with Venturi pipes, rotating heads with nozzles, distribution heads, vertical pipes.

The closest in technical essence to the claimed design is the design of the boiler, in which the fuel is supplied to the boiler through slotted channels installed vertically in the gas distribution grid. Channels pass through the grate. Umbrella-like reflectors are located above the channels. In this case, it is recommended that the reflectors and the walls of the channels located in the layer cooled by water be arranged to be parallel to the furnace front at a distance from each other greater than their width. The movement of fuel through the slotted channels is carried out due to the pneumatic supply system. This requires 10-20% of the amount of air required to fluidize the intermediate fluid.

Uniform feeding of coal by the bed is a significant problem when large furnaces are used and highly reactive coal is used. Poi

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The supply of fuel through slotted channels in principle allows a relatively uniform distribution of fuel over the cross section to be achieved. However, the use of a pneumatic supply system greatly complicates the design of the fuel distribution and reduces the reliability of its operation, increases operating costs, because uniform distribution of fuel requires simultaneous operation of all channels, which leads to intense abrasive wear of structural elements, high pressure air is required.

The aim of the invention is to increase reliability and reduce operating costs.

To achieve this goal, the walls of the fuel supply channel and its distribution device are located above the gas distribution grid and immersed in a fluidized bed, the distribution device is made in the form of a plate inclined to the horizon with the mentioned holes, fastened to the walls at a distance from the lower edges of the latter with the formation of an air cavity, and for uniform distribution of fuel along the length of the channel, the distance from the lower edges of its walls has a constant value along the length of the channel, and sections of the air the cavities are formed by vertical partitions fastened to the channel walls under the plate.

In FIG. 1 shows the design of a fluidized bed boiler; FIG. 2 is a section AA in FIG. 1.

The boiler has a housing 1, a gas distribution grill 2 mounted to it, on which a layer of granular material - an intermediate heat carrier 3 is located. Inside the housing 1 there are heat removal surfaces 4. An umbrella-like reflector 5 attached to the walls is located below the upper level of the intermediate coolant layer. Under the reflector 5 there is a fuel supply channel, consisting of side walls 6 and a gas distribution grill 7 attached between them. Moreover, the reflector and the channel walls are made water-cooled, they can be hollow or from refractory. The sublattice and superlayer portions of the channel are made open, and the reflector is mounted above the gas distribution grid 2 of the boiler with a gap. With a large length of the channel, its sublattice part is made of the same height in length and is partitioned by vertical partitions 8. One end of the channel extends beyond the side wall of the boiler, forming a loading end The channel is equipped with

the ground coal hopper 9 and the feeder 10. With a large area of the mirror of the fluidized bed 3, several parallel channels are installed on the analogy of the prototype

the distance from each other is greater than their width, and the loading ends extending beyond the wall of the boiler are interconnected to reduce the number of screws serving them to one.

0 The boiler operates as follows.

The air coming in through the gas distribution grid 2 brings into a fluidized state the layer of intermediate coolant on it. AT

5, due to the analogy of the properties of the fluidized bed 3 with the liquid, an air cavity is formed in the sublattice part of the fuel supply channel. Air (gas) coming from it through the inclined grating 7 fluidizes

0 ground coal loaded through the feed end of the channel from the hopper 9 by the feeder 10, since the hydraulic resistance for the movement of gases through the fuel supply channel, installed with a gap to

5 of the gas distribution grid 2 of the boiler and made with an open sublattice part, due to the formation of a gas cavity in it less than in the surrounding layer, an intense

0 fluidized coal and it spreads along the gas distribution grid 7 to the opposite wall of the boiler body. As a result of intensive fluidization, the upper boundary of the layer of coal is established

5 horizontally. Due to emissions (bursts of ablation) from the surface of the fluidized bed located in the channel, the particles of coal are intensively thrown up above the bed and, having hit an umbrella-shaped reflector 5, fall into the fluidized bed 3 of the intermediate heat carrier, since the upper boundary of the coal layer is horizontal and the distance to the upper edges of the walls 7 of the channel and the umbrella-like reflector 5 is the same along the length of the channel, then, per unit length of the channel, the same amount of angle enters the fluidized bed 3. Coal burning occurs inside the fluidized bed 3. Heat released during combustion is removed by means of heat removal surfaces 4.

With a large length of the fuel supply channel with an inclined arrangement of the gas distribution grill 7 in the sub-critical part 5, gas overflows along the grill are possible, which can lead to uneven fluidization of the coal located on it and cause uneven distribution of fuel. Therefore, in order to achieve uniform distribution of fuel throughout

the length of the channel, its sublattice part is made of the same height and is partitioned by vertical partitions.

With fractionated solid fuel, i.e., a low content of fines fractions in it, it is advisable to immerse only the sublattice part of the fuel supply channel in the fluidized bed 3 of the intermediate heat carrier, since in this case, the coal is loaded into the channel at atmospheric pressure.

The installation in the fuel supply channel of the gas distribution grid and its location in the fluidized bed above the gas distribution grid of the boiler with a gap determine that the coal is transported in the channel and supplied to the intermediate coolant layer by the air supplied to the fluidization fluid. The same circumstance allows the use of larger coal, which only increases the uniformity of the distribution of fuel in the layer. According to the prototype, 10-20% of the amount of air required for fluidization of the intermediate coolant is required for pneumatic supply. The slotted channels are located in the gas distribution grid of the boiler; therefore, it can be tentatively assumed that the air supply requires 1.2 times more excess air pressure than the fluidization. This in turn allows a 2-4% reduction in energy consumption for fuel distribution. Replacing the pneumatic supply with a distribution using a fluidized bed of coal eliminates abrasive wear

airborne structural elements, increase the reliability of the boiler, reduce operating costs.

Claims (2)

1. A boiler containing a fluidized bed located on the gas distribution grid with heat exchange surfaces immersed in it and umbrella-like A reflector installed with a clearance above the fuel supply inclined channel bounded by vertical walls and connected to a solid fuel supply pipe and a sectional distribution device with holes for supplying fluidizing air, characterized in that that, in order to increase reliability and reduce operating costs, the walls of the fuel supply channel and its distribution device are located above the gas distribution grid and immersed in a fluidized bed, the distribution device is made in the form of a plate inclined to the horizon with 5 by the aforementioned holes, bonded to the walls at a distance from the lower edges of the latter to form an air cavity. 2. The boiler according to claim 1, characterized in that in order to evenly distribute the fuel along the length of the channel, the distance from the lower edges of its walls is constant along the length of the channel, and sections of the air cavity are formed by vertical partitions fastened to the walls channel under the plate. 1778445 Boiler 3 V 3L f g ff gfgfjftf4 L: ....-.:.: .-:; .. g-g- -L. ij I. ; . Air and Figure 1 N 7 " Jo ABOUT J s 2 A-a about h-; -about . o in century , about, Oh in about . " about  J 7 5