JPS59104078A - Fluidized bed spare reducing furnace with internal - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] The present invention relates to a fluidized bed pre-reduction furnace equipped with an internal, and in particular, a vertical bar and a horizontal t! By installing an internal made up of multiple pieces in the furnace, the fluidized bed area can be multi-staged and evenly structured.
There are some related to furnaces that allow for the yield to be obtained.

In recent years, ore raw materials containing iron oxide or various metal oxides have become less bulky ores and more powdery or granular ores, and this trend is expected to become more pronounced in the future.

In view of the current situation, a technology for directly smelting such powdery ore has recently been developed. For example, there is a method in which powdery ore is pre-reduced for 111 hours using a fluidized bed, and then the pre-reduced ore is melted and reduced in an electric furnace, converter or other melting furnace. In the case of this known technology, there are many methods in which a binder is added to the pre-reduced ore to once agglomerate it, and the agglomerated material is melted and reduced in a melting furnace. However, according to such conventional technology, not only does it require extra fuel, processing cost, and processing energy for agglomeration, but also in cases where additional firing is required after agglomeration. When producing fired lumps, NOx in the gas emitted from the IJ is removed from the firing furnace.
, SOx, dust, etc. have to be treated, which has the disadvantage of requiring a large amount of cost.

In addition to the above-mentioned method, a method has also been proposed in which pre-reduced ore is melted and reduced in the form of powder using an arc furnace, a furnace that uses plasma, or pure oxygen. However, the method using an arc furnace not only consumes a huge amount of power, but also has restrictions on location. A method using a furnace that utilizes plasma is difficult to apply on an industrial scale. It is easy to obtain a high-temperature atmosphere using a furnace that uses pure oxygen, but since the oxygen cannot be preheated, the amount of heat input is small, and in addition, it is difficult to maintain a reducing atmosphere.
There are still technical problems that need to be solved, such as the lack of oxygen, and at the same time, there is also the need to prepare pure oxygen production equipment, and there are also locational issues. As described above, many problems remain in the prior art that require technical and economical solutions.

Therefore, recently, the smelting reduction method has been attracting attention as a technology for producing ferrochrome and other ferroirons [1] that does not rely on electric power. For example, there is a method for directly producing ferroalloy from powdery ore using an apparatus that combines a fluidized bed pre-reduction furnace and a vertical smelting reduction furnace. This known method is a method for pre-reducing metal oxide-containing ores in a fluidized bed format using high-temperature exhaust gas from a two-way melting furnace as a source of reducing agent and heat necessary for pre-reduction of ores containing metal oxides. Since the granular ore can be used directly without agglomeration, it is possible to produce molten metal at a lower cost than the above-mentioned method.

The main conditions necessary for the fluidized bed as a pre-reduction furnace in the above-mentioned known method are: (1) easy heat supply to maintain the reaction temperature at which the required reduction rate can be obtained; (2) local overheating and (3) Uniform and stable fluidization phenomenon can be obtained; (4) sintering does not occur due to adhesion of the pre-reduced ore in the high temperature range and fluidization is not inhibited; (3) uniform and stable fluidization phenomenon can be obtained;
) The required reduction rate can be obtained even with a short residence time (multi-stage fluidized bed), and (5) there is little dust generation due to the ladle flying out of the fluidized bed.

However, generally speaking, the higher the temperature of the fluidized bed required for preliminary reduction, the more difficult it is to maintain these various conditions, and moreover, the higher the temperature of the fluidized bed required for preliminary reduction, the more difficult it is to maintain it. The inclusion of dust further increases the difficulty of the method of operation and requires the development of various new method 4b equipment.

This invention (required for a fluidized bed pre-reduction reactor) - A preliminary devised for the purpose of improving the points described in (4) and (5) among the conditions mentioned above. The gist of its configuration is that an inlet for the fluidized reducing gas is provided at the bottom of the furnace, a raw material supply port is provided on the side wall of the furnace facing the fluidized bed area, and a preliminary reduction gas is provided in the fluidized bed area. A fluidized bed pre-reduction furnace having a configuration in which a product discharge port is open, characterized in that the fluidized bed area in the furnace is internally equipped with an interple consisting of a combination of a plurality of vertical bars and horizontal bars. The point is that The details of the configuration will be explained below.

Figure 1 shows a typical 4-coat moving bed pre-reduction furnace.
The furnace body 1 is of a vertical type, and its body is equipped with a supply port 4 for powdery ore raw material facing the fluidized bottom 2 area, where the ore from the ore ho-soba 7 is provided. A feeding device 6 for feeding ore into the furnace is installed. In addition, a gas distribution plate (grate) is installed inside the furnace to retain and flood the ore.
A high temperature reducing gas inlet 8 is opened in the lower part of the furnace. As the reducing gas, high-temperature exhaust gas generated from a heating furnace, a reducing gas generating furnace, or a melting reduction furnace is used, and is used as a reducing agent and a fluidizing gas. By introducing this reducing gas into the furnace, the powdery ore on the gas distribution plate 3 is fluidized, forming a fluidized bed 2, and fluidized reduction can be performed. Note that 9 in the figure is a reducing agent supply port through which a hydrocarbon-containing gas such as methane is supplied as a reducing agent. 7. Reference numeral 10 in the drawing indicates an exhaust gas outlet, and since the exhaust gas from the fluidized bed 2 discharged through this outlet contains a large amount of dust 1, the cyclone 11 is used to remove the dust. On the other hand, the preliminary reduction product is discharged from the upper discharge pipe 5 of the fluidized bed 2 area and transferred to the next step, such as a smelting reduction furnace.

In the above-mentioned preliminary reduction furnace, for example, in the case of chromium ore, the temperature for preliminary reduction is 950~'+10
The temperature at which 0 'C ore is sintered is said to be around 1250 to 1350 degrees Celsius. Such ore is prepared by a fluidization reaction in the pre-IIFi reduction furnace described in 1-1. Considering the reduction case, the child Wi
In an attempt to maintain the reduction temperature necessary for reduction by the sensible heat of the fluidizing reducing gas, which is used as a fluidizing gas,
It is necessary to introduce extremely high-temperature fluidizing reducing gas, and as a result, the depletion of the reducing gas exceeds the above-mentioned sintering limit temperature. Since ore (i) is often heated to a humidity higher than the sintering limit humidity, sintered lumps and dirt may grow, which may clog the gas distribution plate 3 or inhibit the fluidization reaction. In order to solve these problems, the introduction humidity of the fluidizing reducing gas can be lowered, but simply lowering the temperature will lower the binary temperature and reduce the reduction rate.

Therefore, C', the present invention provides an effect similar to that of stabilizing the fluidized bed and increasing the number of stages by installing an internal as shown in Figs. 2 and 3 in the fluidized bed area in the throat of the furnace. It is what it is.

Due to the high temperature inside the furnace, it is desirable that such internals have a particularly simple size of up to 114 mm due to their heat resistance. The example in Figure 2 shows the bar-shaped vertical beam 12... and the same prefecture 4.
The horizontal bars 13... of Δ are installed in parallel with each other with an appropriate interval between them.
2. The pine beam 13 is fixed to the furnace wall at 1[v] contact. The internal shown in Fig. 3 is an example in which a plurality of rods are assembled in a lattice shape, and the gas dispersion plate 3 is omitted, and the lattice-shaped internal 14 is given a waste dispersion effect, resulting in a uniform and stable The fluidization reaction is ensured and the disadvantages of installing the gas distribution plate 33 are eliminated.

d3. As the internal material used in the above-described embodiments of the present invention, other than bar material, thin plate material, mesh, etc. can also be used.

As explained above, by installing the internal according to the present invention in the fluidized bed 2 area, the fluidization reaction can be improved in each group/lateral Vi1.
2 and 13, it sometimes shows a partitioned flow and exhibits the same effect as multistage, while at the same time reducing fluidization leaks and pressure fluctuations, and suppressing the growth of bubbles, etc. The reaction rate of the gas increases, uniform and stable fluidization can be ensured, and the preliminary reduction rate can be improved.

[Brief Description of the Drawings] Figure 1 is a route diagram of a conventional general fluidized bed pre-reduction reactor, and Figure m2 is a route diagram of a fluidized bed pre-reduction reactor equipped with internals showing an embodiment of the present invention. 3 are route diagrams of a flow #J layer pre-reducing furnace equipped with internals showing another embodiment of the present invention. 1... Pre-reduction furnace 2... Fluidized bed 3... Gas distribution plate 4... Powdered ore supply port 5... Pre-reduced ore discharge port 6... Supply device (valve) 1...・Ore hopper 8... Fluidization reducing gas inlet 9... Hydrocarbon-containing gas is supplied J lo... Exhaust gas () 1 outlet 11... Cyclone 12... Vertical bar 13... Horizontal bar 14...
Lattice Internal Patent Application λ Kawasaki Steel Corporation Figure 1 Figure 2 ;) Diagram Company Chiba Works

Claims (1)

[Claims] 1. An inlet for the fluidized reducing gas is provided at the bottom of the furnace, a raw material supply port is provided on the side wall of the furnace facing the fluidized bed area, and an outlet for pre-Ia reduction products is provided in the fluidized bed area. In a fluidized bed pre-reduction furnace having a configuration in which the opening is avoided, C1 is characterized in that internals consisting of a combination of a plurality of vertical bars and horizontal gutters are installed inside the fluidized bed area in the furnace. Eruryu IJ Fj pre-Ull'rim former furnace.