JPS5847216B2 - Chiyokuretsutadanriyuudousogasbunsansochitsukihannouro - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of a reduction reactor for fine iron ore using serial multi-stage fluidized beds.

In reactors that use serial multi-stage fluidized beds, a wind box is installed at the bottom of the dispersion plate for the purpose of uniformly dispersing the gas.
In addition, in order to obtain a sufficient distribution plate resistance, a distribution plate having a large number of small holes is usually used.

However, in products that require operation at high temperatures (800 to 900°C), such as powdered iron ore, sintering and growth of particles, adhesion, and accumulation of fine powder occur particularly on the dispersion plate, causing homogeneous flow and non-flow parts. It is necessary to have a structure without

However, with conventional dispersion plates, long-term continuous operation was not possible due to sintering of particles.

Observing this phenomenon, the first problem, the sintering growth of particles, is caused by the so-called non-flow zone, which is a blind area to the gas flow on the top surface of the gas distribution plate, in a porous or bubble cap type general gas distribution plate. This is due to the creation of dead space.
Sintering is promoted using this part as a foothold, making safe operation of the fluidized bed difficult.

A second problem is the accumulation of fine particles on the side walls of the gas flow path.

This is because when a gas flow with fine powder is not smooth, or when the gas flow changes direction sharply, a stagnation area is created in the gas flow path, and at the same time, a vortex is created in this area, causing the wall of the flow path to stagnate. Fine powder adheres to and elongates, which further generates new small eddy currents and promotes the adhesion and accumulation of fine powder.

The present invention focuses on such a phenomenon and proposes a gas dispersion device that eliminates the above-mentioned drawbacks.

In order to solve the first problem, the present invention uses triangular, square, or hexagonal columnar unit blocks 2 as constituent elements of the gas distribution plate 5.

As shown in Figs. 1 and 2, the unit block 2 has a columnar outer shape, and a small diameter cylindrical gas introduction passage 3a is provided on the bottom side, and the top of the inverted truncated pyramid-shaped passage is connected to this for diffusion. This constitutes the passage 3.

The number of slopes of the pyramid is the same as the number of sides of the prisms forming the outer shape of the unit block 2, and the upper surface of the unit block 2 forms a ridge line 4.

The illustrated example shows a hexagonal columnar unit block, but a hexagon is close to a circle, and it is easy to assemble a plurality of unit blocks to form a plate of any shape. It is desirable to do so.

A unit gas dispersion element 1 is constructed by connecting a cyclone 14 every 11 blocks to this unit block 2.

Next, when the gas distribution plate 5 is formed by assembling a plurality of units of the unit gas dispersion element 1, the upper surface of the gas distribution plate 5 becomes a collection of hexagonal ridge lines, and the ridge lines give a so-called honeycomb-like appearance. It is intended to be presented.

Note that when the gas distribution plate 5 is made into a disk shape, a filling block 6 is required around the periphery.

In such a gas distribution plate 5, there is no so-called dead space and no particles are sintered.

Regarding the second problem, since the cyclone 14 is connected to the gas inlet 3a, most of the differential in the high-temperature gas entering the unit block 2 is removed by the cyclone 14, so no dust is included. The amount is small, so there is less opportunity for fine powder to adhere to the gas inlet 33, etc., and furthermore, the fine powder in the gas that cannot be removed by a cyclone is also collected in the fluidized bed in the upper reactor, so the fine powder adheres and grows. There is no problem with continuous operation of the equipment.

An embodiment of a reactor having a gas distribution plate 5 according to the present invention will be described with reference to FIG.

The reactor 7 consists of an upper stage reactor 8 and a lower stage reactor 9, and fine ore is supplied to the upper stage reactor 8 from a fine ore population 10.

The high-temperature reducing gas enters the gas chamber 12 of the lower reactor 9 through the reducing gas inlet nozzle 11, flows through the lower dispersion plate 13, and reduces the ore present on the plate.

The reducing gas that has exited the lower reactor 9 is separated from the dust contained in the gas by a cyclone 14 installed on the lower surface of each unit block 2, and then enters the diffusion passage 3 through the gas introduction passage 3a and is then transferred to the upper reactor. It fluidizes the fine ore in step 8, preheats the fine ore, and partially reduces the ore.

The gas that has passed through the fluidized bed 8a of the upper reactor 8 is passed through the upper internal cyclone 15 to remove dust from the gas, and is discharged from the reducing gas outlet nozzle 17 via the collecting chamber 16.

The dust collected by the upper internal cyclone 15 is returned to the fluidized bed 8a of the upper stage reactor 8, and the dust collected by the cyclone 14 is returned to the fluidized bed 9a of the lower stage reactor 9.

The fine ore preheated in the upper stage reactor 8 is sent to the fluidized bed 9a of the lower stage reactor 9 through the overflow pipe 18.

The fine ore that has undergone the reduction reaction is taken out from the product outlet nozzle 19.

In this case, the cyclone 14 is a single cyclone and there is a limit to its dust collection efficiency, but the gas diffusion passage 3 of the unit block 2 has a good surface finish and a smooth diffusion shape, so there is no adhesion of dust. Fluidized bed 8
a and will be collected here.

That is, by providing in the reactor T the dispersion plate 5 in which the unit gas dispersion elements 1 in which the unit blocks 2 and the cyclones 14 are combined are provided to prevent the adhesion and growth of dust, and the upper surface of the dispersion plate 5 is made up of only ridge lines. Therefore, there is no so-called dead space and there is no opportunity for particles to sinter.

In short, by carrying out the present invention, it is possible to prevent the adhesion and growth of dust and the sintering of particles in the fine ore reduction reactor, particularly on the gas distribution plate, and to have the effect of enabling long-term continuous operation of the reactor. .

[Brief explanation of the drawing]

Figure 1 is a plan view of the unit block, Figure 2 is its side view,
Figure 3 is a plan view of the filling block, Figure 4 is its side view,
FIG. 5 is a partial plan view of a gas distribution plate according to the present invention, FIG. 6 is a view taken along the line AA in FIG. 5, and FIG. 7 is a longitudinal sectional view of a reactor according to the present invention. 1...Unit gas dispersion, 2...Unit block, 3.
...Diffusion passage, 4...Ring, 5...Gas dispersion plate, 6.
... Packing block, 7... Reactor, 8... Upper reactor, 9... Lower reactor, 8a... Upper fluidized bed, 9a
...lower fluidized bed, 10...fine ore inlet, 11...
Reducing gas inlet nozzle, 12... Gas chamber, 13... Lower dispersion plate, 14... Cyclone, 15... Upper internal cyclone, 16... Gathering chamber, 17... Reducing gas outlet nozzle, 18...Overflow pipe, 19...°Product outlet nozzle.

Claims (1)

[Claims] 1. Reaction with a series multi-stage fluidized bed gas dispersion device characterized by having a gas dispersion plate consisting of a plurality of unit gas dispersion bodies formed by connecting a unit block having an inverted truncated polygonal pyramid passage and a cyclone. Furnace.