SU907376A1 - Fluidised bed apparatus gas distributing grate - Google Patents

Description

The invention relates to a technology for firing bulk materials in a fluidized bed, in particular for the production of high-quality lime, and can be used in the metallurgical, chemical industries and the building materials industry.

A fluidized bed lattice apparatus for carrying out the process of liquefying solid particles is known, containing horizontally placed across the flow area of ha- ¹⁰ behind the plate. The plate has a series of holes in which nozzles diverging downward are installed, extending beyond the lower surface of the plate. The nozzles are located quite far from each other (leaving “dead spaces ₁₅ ” on the underside of the plate above their inlet sections. The nozzle walls diverge at an angle of 2 to 30 °. The installation ensures a smooth flow that “flushes” solid particles from the nozzle walls preventing them from sticking to the lattice [1]. 20

The disadvantages of the design are the bulkiness and the possibility of overgrowing holes on top of the grill.

Also known is the lattice of a three-chamber fluidized bed furnace for burning cracked rocks, containing a hearth recruited from refractory blocks, in each of which a hole is molded. A removable diaphragm insert is inserted into the hole, which is removed after the walls are overgrown [2].

The disadvantages include overgrowing of the grate from above, as well as stopping the furnace and cooling it to change diaphragms.

Closest to the technical nature of the invention is a grate for supplying a fluidizing agent to the fluidized bed, which is a system composed of caps. The cap consists of a short channel made in the form of a truncated cone, expanding along the gas. A ball is placed in each channel, which pops up with an increase in gas flow, which causes a corresponding increase in the free section for its passage. The design of the cap eliminates the failure of the particles of the layer with sudden decreases in gas flow. In addition, the presence of steam in the channel can prevent overgrowth inside the channel [3].

The disadvantage is the overgrowing of the lattice recruited from the caps, on top. Such growths cover the outlet openings of the caps and the structure will not work.

The purpose of the invention is to increase the duration of operation of the furnace.

This goal is achieved by the fact that in the gas distribution grid of the apparatus with a fluidized bed containing a perforated plate with balls, the latter are freely placed on the surface of the grating in the amount of 1/7 = 1/9 of the number of holes of the plate and are made with a diameter determined by the formula

J DB'resh, ' ^d o ₍ ² Ush where ΔΡρββ is the resistance of the grating, kg / m ² ; d _{o is the} diameter of the opening of the grating, m;

- the specific gravity of the ball material, kg / m ³ ;

In order for the balls not to be ejected from the grate and not to cover the holes of the grate, the weight of the balls must be equal to the dynamic pressure of the jet flowing out of the hole of the grate F _CTMII ⁼ ^ “·

Since R _W =.

^ jet ^ APpd _0IB = DDR <£ _m l _ 3 · A Rresh ^ o.

w and _w - -_

Osh

The diameter of the ball is chosen larger than the diameter of the hole of the plate to prevent failure or jamming of it in the hole of the plate.

The material of the ball is selected so that it does not collapse from exposure to particles of the layer and does not deform the holes of the lattice.

In FIG. I shows the gas distribution grill of the apparatus with a fluidized bed, cross section; in FIG. 2 - square arrangement of holes; in FIG. 3 - a triangular arrangement of holes.

Gas distribution grill (Fig. 1 contains a plate 1 with holes 2 with a diameter of d _{0 with a} pitch between them L. On the plate are placed balls of minimum 3 and maximum 4 sizes.

The minimum number of balls is in the range 1 / 7-1 / 9 of the number of holes. Such a number of balls is due to the fact that their movement through the holes is excluded. In this case, with a triangular arrangement of holes in the lattice, the minimum number of balls is 1/7 of the number of holes, and with a square 1/9.

The lattice works as follows.

The fluidizing agent flowing out of the openings 2 lifts the balls 3 and 4 above it. The oscillations of the balls 3 and 4, which occurs due to pulsations of the fluidized bed, lead to its collisions with the edges of the holes. 2, and also move balls 3 and 4 from one hole 2 to another, which prevents the formation of dust deposits in them.

When using the lattice, dust overgrowth is excluded, which increases the overhaul life of the furnace. The advantage of the grate is also the elimination of the cost of manual labor for its cleaning.

Claims (3)

(54) GAS DISTRIBUTION GRID OF A MACHINE WITH A BOOSTER LAYER The invention relates to the technology of firing loose materials in a fluidized bed, in particular for the production of high quality lime, and can be used in the metallurgical, chemical industry and industry of building materials. The known fluidized-bed apparatus grid for carrying out the process of fluidization of solid particles, comprising a plate horizontally placed across the area of the gas flow. The plate has a series of holes in which nozzles are installed downwardly extending beyond the bottom surface of the plate. Nozzles are located quite far from each other; left “dead gaps on the underside of the slab above their entrance areas. The walls of the nozzle diverge at an angle of 2 to 30 °. The installation ensures a smooth flow, which “removes solid particles from the nozzle walls, an obstacle to their adherence to the 1J grid. The disadvantages of the design are cumbersome and the possibility of overgrowing of the holes on top of the grid. Also known is the grid of a three-chamber fluidized bed furnace for the firing of cracked rocks, which contains a hearth made of refractory blocks, each of which is formed a hole. A replaceable diaphragm insert is inserted into the hole, which is removed after the wall overgrowth 2. The disadvantages include the overgrowing of the grate from the top, as well as stopping the furnace and cooling it to change the diaphragms. Closest to the technical nature of the invention is a grating for supplying a fluidizing agent to a fluidized bed, which is a system made up of caps. The cap consists of a short channel made in the shape of a truncated cone, expanding along the gas flow. A channel is placed in each channel, which pops up with the growth of gas flow, which causes a corresponding increase in the free cross section for its passage. The design of the cap eliminates the collapse of the particles of the layer with a sudden decrease in gas flow. In addition, the presence of steam in the channel can prevent overgrowing inside channel 3. A disadvantage is the overgrowing of the grille assembled from the caps from above. Such growths cover the outlet openings of the caps and the structure will not work. The purpose of the invention is to increase the duration of operation of the furnace. This goal is achieved by the fact that in the gas distribution grid of a fluid bed apparatus containing a perforated plate with balls, the latter are freely placed on the surface of the grid in the amount of 1/7 1/9 of the number of plate openings and are made with a diameter defined by the formula d. -ctp where LRrea is the resistance of the grid, kg / m; do - diameter of grating hole, m; Usch - the specific weight of the material of the ball. In order for the balls not to be thrown out of the grid and not covered by the grid holes, the weight of the balls must be the dynamic pressure of the jet emanating from the hole of the grid ТСТР. .. The diameter of the ball is chosen larger than the diameter of the hole of the plate to prevent the failure or jamming of it in the hole of the plate. The material of the ball is selected so that it does not collapse from the action of the particles of the layer on it and does not deform the holes of the grid. FIG. G shows the gas distribution grid of the apparatus with a fluidized bed, the cross section; in fig. 2 - square arrangement of holes; in fig. 3 - a triangular arrangement of holes. The gas distribution grid (Fig. 1 contains a plate 1 with holes 2 with a diameter of dots pitch between them L. On the plate there are balls of minimum 3 and maximum 4 sizes. The minimum number of balls is within 1 / 7-1 / 9 of the number of holes. Such the number of balls is due to the fact that they are not moved through the holes, in which case the minimum number of balls in the triangular arrangement of the holes in the crate is 1/7 of the number of holes and in square 1/9 the grid works as follows. A vent flowing out of the holes 2 lifts the balls 3 and 4 above it. The fluctuations of balls 3 and 4, due to the pulsations of the fluidized bed, cause it to collide with the edges of the holes 2, as well as move the balls 3 and 4 of one hole 2 into the other, which prevents the formation of dust deposits in them. When using the grate, it is not covered with dust, which increases the turnaround time of the kiln. Claims of gas distribution apparatus of a fluidized bed apparatus containing a perforated plate with balls, characterized in that, in order to increase the duration of operation of the furnace, the balls are freely placed on the surface of the grid in quantity 1 / 7-1 / 9 of the number of holes in the plate and made with a diameter defined by the formula d, where APpeiu is the resistance of the lattice, do is the diameter of the opening of the lattice, m; Y - the proportion of the ball, kg / m. Sources of information taken into account in the examination 1. US patent number 3910769, cl. 23-284, pub. 1973. 2. US patent number 2548642, cl. 263-53, published. 1943. 3. Patent Czechoslovakia number 162224, cl. 12 G 1/01, publ. 1976. 2 .З