MXPA99004340A - Device for discharging or mixing lump materials - Google Patents

Abstract

A device for discharging or mixing lump materials from a shaft furnace with a hollow body for discharging the reaction materials open at the bottom and/or at least to one side, has screws arranged in a star-shape in the hollow body. These screws have shafts of different lengths in a plane and/or one screw is a continuous screw. In one of the possible combinations of floating shafts (2) of three different lengths, the shafts are arranged in the shaft furnace (1) so as to form an eight-pointed star, the opposite floating shafts (2) having the same length. The"dead"or non-stirred area at the centre of the shaft furnace is extremely reduced in this combination.

Description

ARRANGEMENT TO DOWNLOAD ¥ MIX MATERIAL IN MASS DESCRIPTION OF THE INVENTION: The invention relates to an arrangement for unloading and mixing a material of undefined mass, in particular mineral and partially and / or completely reduced iron and from a shaft furnace, preferably a direct reduction tub furnace, comprising a hollow body that opens downwards and / or at least one side to discharge the reaction material, where hollow body screws are radially arranged. EP-B 166 679 describes screws of equal length and cylindrical cross-sections for moving solid particles in a shaft furnace and discharging solid particles from that shaft furnace, which are radially arranged and cantilevered, the dead corners are brought to a minimum when installing wedge-shaped derailleurs between the screws. This arrangement has the disadvantage that the area of dead corners, which is also referred to as "dead man" is reduced by the derailleurs, but at the same time the active volume is maintained. EP-B 85 290 describes short conical screw arrangements, which are mounted on a tapered derailleur in the center, which at the same time serves as the angle of repose, as well as along the circumference. As indicated in the REF .: 30190 patent EP- B- 166 679 the arrangement is radial and opposite diagonally and displaced by the same angle. CH-A 376 134 describes a process to reduce iron ore to iron, where the bulk material is transported by screws diametrically placed, the screws show a constant pitch and height and are seated on cylindrical axes that are supported by both sides. GB-A 15 02 090 discloses screw conveyors arranged in parallel with a shape of a tapered screw which serve to discharge iron ore, the axes are connected to one another by means of webs V and are driven synchronously. In the reduction of minerals by reactive gases, it is an economic necessity to carry a volume of specific gas weaker than the stoichiometric, in contact with the mineral. However, this requires a homogenous gas distribution as well as a sublateral uniform movement of the solid bed in the shaft furnace. In a shaft furnace, for example according to a COREX process (m.r.) the solids are moved and unloaded by screws arranged radially at the lower end of the shaft. To ensure that the bulk material falls as evenly as possible, the area located at the bottom of the tank must be composed of a maximum discharge area, and in addition, a continuous and complete movement mixing of the reaction zone must be ensured. Areas that do not move create very steep angles of rest and are formed above non-active areas. These areas that are mentioned as "dead man" have the essential disadvantage that the percentage of volume of the reaction space becomes partially inactive.As a result, there are agglomerations and lumps in those regions, due to the long residence times of minerals and already reduced minerals which disadvantageously affects the flow of material and consequently reduces the reaction of material and thus production.In this state of the art, where the screws are cantilevered and have equal lengths, almost no there is movement in the central region of the tank, due to the fact that the gas flow is concentrated in the center of the tank if gases loaded with dust are fed through the nozzles mounted along the circumference, the gas It will not be distributed homogeneously The technical problem of the invention is to avoid those regions where there is no movement, to keep the regions s of reduced movement and at the same time bring to a maximum the active volume of the material in movement in the tank. Active volume means the region of a shaft furnace where the solid-gas reactions take place continuously. The invention is characterized in that the screws are arranged at one level and have different lengths. A preferred development is characterized in that the opposite bolts have equal lengths and / or a bolt is designed as a through bolt. The arrangement of screws of different length ensures that also those regions of the unloading area, close to the center can be activated. The arrangement provides a greatly exhaustive and sub-lateral continuous mixing of the bulk material in particular at the top of the tub in the reaction space areas where the reducing process occurs. The invention for the first time allows to achieve uniform mixing and continuous discharge of the solids in the reaction area of a direct reduction cell furnace. The invention adjusts the arrangement and the design of the screws optimally to the dynamic fluid conditions of the reaction participants, as well as solids and gases. For example using cross bolts combined with short bolts, the "dead man" areas can be extremely reduced in size, especially because inactive solid beds are hardly formed at relatively close distances from the active bolts. By placing, for example, 4 long and 4 short screws, the active area can extend to the peripheral edges. By installing a short and a long screw the discharge of the product can be combined each by means of a discharge tube downwards. Due to this measure, the arrangement of the tubes downwards will be better adjusted to the geometry of the melting gasifier there coupled. By combining long and short screws, the behavior can be adjusted to both the movement and the discharge of solids through the design of the screw in such a way that both the discharge operation and the mixing characteristics can be influenced. Basically, however, the behavior of the solid bed can be influenced. According to a feature of the invention, the screws are arranged on two or more levels so that the bottom of the oven can move better. According to another feature of the invention, the opposed long screws are of a self-centering and / or self-gripping design. If the screws are installed in an existing bed, it must be ensured that the screw halves are between each other and that they are centered. According to a feature of the invention, the helical surfaces of the screws start from their free ends. As a result, the core zone is optimally mixed and the discharge reaction product constantly. According to another characteristic of the invention, the screws are tapered toward the center so that the cross-sectional active section of these regions of the reaction zone moving through the screws are brought to a maximum. According to another feature of the invention, the helical surfaces of the screws show a constant pitch. The development provides a uniform feeding behavior above the cross section of the screw. According to another characteristic of the invention, the helical surfaces of the screws show different steps or spaces related to the process. Due to a non-linear pitch of the helical surfaces of the screws, the reaction behavior of the melting gasifier as well as the behavior of the fluid of the reaction material can be taken into account. Due to the mathematically simulated development of the feedstocks, the reaction material in the vessel as well as the reaction behavior of the reaction gas can be taken into consideration. According to another development of the invention, coupled motors are provided to drive the screws. If the screws are driven by motors, the screws can adjust themselves flexibly to the process and can move on their own impulse during installation and dismantling. According to another characteristic of the invention, the long and short axes have the same speed. If a plant that includes the minimum expense, is demanded, preferably an uncontrolled operation of the engines will be implemented. As a result, the screws will have approximately the same speed but will not include any control expense. According to another characteristic of the invention, the speeds of the individual screws are controlled according to the feeding characteristics of the process. Due to the controlled operation of the screws, the related energy as well as the requirements related to the process of the reaction zone of the fusion gasifier can be taken into account. According to another feature of the invention, the screws are axially movable. During the inspection or in the case of failure, the screws can be installed more easily or dismantled, in case of irregularities in the reaction zone, the behavior of the fluid can be decisively influenced by changing the depth of immersion of the screws. According to one embodiment, the sheets forming the helical surfaces have a shape corresponding to the feeding characteristics of the process. Due to this modeled shape, the cake behavior of the solids bed and the formation of the reaction zone can be taken into account. According to a last characteristic of the invention, the helical surfaces of the screw bodies have a shape corresponding to the characteristics of the process. This adjustment ensures an optimum relationship between the reactivity of the filler materials and the geometrical conditions of the reduction tank. The invention is described in more detail by means of embodiments, with Figure 1 showing eight screws of different lengths in a shaft furnace. Figure 2 six screws of different lengths in a vat furnace, Figure 3 the combination of screws of two different lengths. Figure 4 the arrangement of two cross-bolts in a shaft furnace, Figure 5 the top view of an arrangement of two cross-head screws in a shaft furnace. Figure 6 the combination of a cross-bolt with six cantilevered screws, Figure 7 the same as cantilever bolts. Figure 8 the self-centered and self-gripping version of a through-bolt. Figure 9 the cross section of this connection. Figure 10 a self-centering version of a through-bolt, and Figure 11 the cut through the connection. Figure 1 presents an example where the cantilever screws 2 of two or three different lengths are combined radially to form an octagon in the vat furnace 1. The area of "dead man" this is the inactive space of the furnace in the center of the tank, is extremely reduced by this combination. Figure 2 presents an example where cantilevered screws 2 of two different lengths are combined, which are arranged radially to form a hexagon in the shaft furnace 1. In this combination, the regions near the edge of the furnace are mixed less completely , and the material to be unloaded is not discharged as uniformly as shown in Figure 1. Figure 3 shows an example of a cantilevered screw 2 embodiment of two different lengths also combined, where however, they are arranged radially to form an octagon. The movement in the region near the edge of the vat l is better than the case in Figure 2. Figure 4 shows the spatial arrangement of the combination of two pitch screws 3 in the vat honors 1. Figure 5 shows the plan view of the arrangement according to Figure 4 where four cantilever screws of the same short length ensure optimum movement of the material at the first level of the screw of step 3. Figure 6 presents the combination of 1 screw of step 3 with six cantilevered screws 2 in the shaft furnace 1. Figure 7 presents six cantilevered screws 3 on a level with a pitch screw.

Figure 8 shows the adjustment of the two screw halves of the through or through screw 3, where the adjustment is serrated for the purpose of centering and mixing. The half of the screw has the advantage that it is in the middle of the screw during the drilling of the bed of a tank furnace that has not yet been drained. Figure 9 presents the cut through the self-centering toothed connection of the screw halves of a pitch screw. Figure 10 shows the section of cross section of the longitudinal view of a central connection of screw halves of the screws of passage 3. Figure 11 presents a section through the central adjustment of the screw halves of the screw 3. Controlling the speed of the drive motors of the shaft halves ensures exact adjustment and exact characteristics of the screw halves It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects or products to which it refers-

Claims (14)

1. REi \ ro ©? A? PoNES
2. Having described the invention as above, the claim contained in the following claims is claimed as property: 1.- Arrangement for unloading and mixing bulk material or lumps, in particular partial and / or reduced iron ore from a vat furnace, preferably a direct reduction tub furnace, comprising a hollow body open downwards and / or at least sideways to discharge the reaction material, wherein the screws of the hollow body are arranged radially, characterized in that the screws arranged in a level have different lengths. 2. Arrangement according to claim 1, characterized in that the opposite screws have equal lengths and / or a screw is designed as a pitch screw.
3. 3. Arrangement according to claim 1 or 2, characterized in that the screws are arranged in two or more levels.
4. 4. Arrangement according to any of claims 1 or 2, characterized in that the opposed long screws are self-centering and / or grappling design.
5. 5. Arrangement according to any of claims 1-4, characterized in that the helical surfaces of the screws start from their free ends.
6. 6. Arrangement according to any of claims 1-5, characterized in that the axes or rods of the screws taper towards the center.
7. 7. - Arrangement according to any of claims 1-6, characterized in that the helical surfaces of the screws show a constant pitch.
8. 8. - Arrangement according to one of claims 1-7, characterized in that the helical surfaces of the screws have different steps in relation to the process.
9. 9. - Arrangement according to one of claims 1-8, characterized in that coupled motors are provided to drive the screws.
10. 10. - Arrangement according to one of claims 1-9, characterized in that the short screws and the long screws have the same speed.
11. 11. - Arrangement according to one of the claims 1-10, characterized in that a control of the speeds of the individual screws is provided in accordance with the feeding characteristics of the process.
12. 12. - Arrangement according to one of claims 1-11, characterized in that the screws move axially.
13. 13. - Arrangement according to any of claims 1-12, characterized in that the helical surfaces of the screw bodies have a shape that corresponds to the characteristics of feeding the process.
14. 14. Arrangement according to any of claims 1 -13, characterized in that the sheets forming the helical surfaces have a shape a that corresponds to the characteristics of the feed.