US3799368A

US3799368A - Loading system for blast-furnace

Info

Publication number: US3799368A
Application number: US00203996A
Authority: US
Inventors: J Wieczorek
Original assignee: Individual
Current assignee: Individual
Priority date: 1970-12-04
Filing date: 1971-12-02
Publication date: 1974-03-26
Anticipated expiration: 1991-03-26
Also published as: FR2116298A1; FR2116298B1; DE2159931A1; PL89653B1; GB1378165A; LU64402A1

Abstract

A loading system for a blast-furnace having a very high counterpressure, characterized by a rotary distributor, a throat member and a ring member mounted between the said distributor and throat member, the said ring member being gas sealed at high pressure and temperature, the said distributor comprises a conical spout adapted to rotate with the ring member, a weir pipe connected to said spout at an angle of approximately 40* to 50* from the vertical, a liquid tubing located along the axis of rotation of the said distribuotr and ring member, the said tubing adapted to receive a cooled liquid for cooling the spout, the said spout being adapted to spread materials such as coke, sintered ores, and various additions inside a blast-furnace to give the said materials an M profile.

Description

Pmmcnmasm 3799.368

sum 2 or a PAIENIEB R26 I974 saw u am FIGS LOADING SYSTEM FOR BLAST-FURNACE This invention relates to the loading system of a blastfurnace operated at a very high counter-pressure, according to systems in M, 2M and 3 M, that is to say, that a vertical section of a blast-furnace shows the loading line of the materials to the throat as 1M, 2M or 3M. Loading in M has been known for a long time by blastfurnace specialists, but loading in 2M or 3M is new to them. The same system is used for the three types of loading, and a very high counterpressure of more than 2 bars, or 30 psi is obtained by means of two valves connected in series with a rotary extractor for the material enclosed in a bin, which can resist very high pressure. The lay-out of the essential elements and the functioning principle of this system prevents the wear between contacting surfaces of the extractor and of the seats of the valves.

The main idea of this invention is to use 2 or 4 or 6 bins, according to the desired loading, i.e., a loading in M, 2M or 3M. While 1, 2 or 3 bins are loaded with materials by conveyors or skip-cars, 1, 2 or 3 other bins unload their contents in the throat by means of a turning spout which is located in the axis and at the top of the metal shell of the blastfurnace.

Systems in M, 2M or 3M allow for an almost unceasing loading of the minerals, coke, various additions and sinter pellets in a given order and in carefully proportioned quantities without any alteration in the counterpressure of the blast-furnace which remains nearly constant and very high, contrary to standard blast-furnaces in which, during any loading, there is a very important falling of pressure.

If the standard system of loading with bells and cones is satisfactory for useful volumes up to 2,500 m and a counter-pressure up to 1,5 bar, for a 4,000 m volume with a counter-pressure exceeding 2 bar, sizes and weights of the elements of the loading system become huge and very difficult to work out. The resistance to abrasion and the tightness of the system imply very frequent overhauls and partial stoppages with the consequence of very big production losses. For a quick overhaul of systems up to 150 tons, some builders, at a level higher than 80 meters lay out a bridge crane of almost 400 tons weight, and it implies the building of giant square towers.

The system of loading in M, 2M or 3M has the great advantage of being simple, comparatively light, easy to assemble, to keep and to repair because the heaviest element weighs less than tons. The possibility of working with half of the equipment, without any stoppage of the blast-furnace, with only a temporary slowing down, during the repair of the defective elements is one of the main qualities of these constructions.

The main advantages sought for during the research for these loading systems in M, 2M or 3M were obtained as follows:

1. The very high counter-pressure and the lasting tightness was obtained from the upper two-way duct, by using in series, a seat valve controlled with a lower tightness seat which never touches the very abrasive materials such as coke and sintered pellets, this valve standing on a bin which can resist very high pressure and temperature, with in the lower part a rotary extractor with pellets in a barrel, also avoiding the abrasion of the walls by its direction of rotation. Then stands a second seat valve, built in a similar way to the upper valve. It is held by means of a sleeve to the hood of a rotary distributor, which has the shape of a cone going into the throat of the blast-furnace and by means of a single, double or triple pipe, unloads materials into the blast-furnace, while rotating at a speed of 15 to 30 revolutions per minute. The part which stands in the blastfurnace under a gas temperature of 400 to 500 C must be cooled by water circulation in a water-jacket. The inlet of water and its outlet is aligned with the rotation axle by means of a particular bearing. The throat of the distribution is held in a tight ring, with a bearing having cross rollers, the said bearing has to support a dissymetrical load. This ring, strongly and precisely built, must also avoid any leakage of hot gas from the blastfurnace. The rotation of the funnel distributor is made by a reducer and an electric motor.

2. The reduction of weights and sizes of the equipments, the economy on electric energy, are obtained by means of a working cycle which is almost continuous, based on the reciprocating functioning of 2 identical assemblies of the system which work in relays to carry out at the same time, either the filling up of the bin or the loading of the blast-furnace. So, when the upper valve opens, the two-way duct guides materials to one of the bins, the extractor of which has stopped, the other bin is under pressure, with its upper valve shut, its lower valve opens and the extractor is working. When a bin is loaded, the other one is unloaded and vice versa. The following stages go on uninterrupted. The times of the different operations depend on the characteristics required for a blast-furance and on the size of equipments.

a. When the storage bin is empty and under high pressure, the upper valve being shut, the rotary extractor stops, the lower valve shuts. The bin is put under decompression by evacuation of gas. When the bin is at atmospheric pressure, the upper valve opens. Into the storage bin which stands between the gas uptakes the upper two-way duct or a skip car, pours a load of materials which is carefully prepared and in a proportioned quantity.

b. When the storage bin is full*of ore, coke, sintered pellets or other additions of the load, the upper two-way duct rotates to stop the filling up, the upper valve shuts, the bin is put under pressure by the inlet of gas from the first dust separator, the pressure of which is almost similar to that of the throat and the temperature of which is slightly lower. The vaporization of humidity of materials charged can raise the pressure a little but does not interfere with the following operations, on the contrary.

c. When the bin pressure is in balance or superior to the pressure in the throat of the blast-furnace, the lower valve opens by swinging out of the way of the fall of materials. The extractor is set to work and pours portions of materials in the duct related to the distributor. The path followed by the abrasive materials avoids as much as possible the abrasion of the extractors body during its rotation. The materials are lifted up during the taking away in the storage bin and fall into the turning spout without wearing out the extractor. Removable and very hard plates are nevertheless provided, such as to avoid, as much as possible abrasion and to be replaced easily, in a hurry, and without stoppage of the working blast-furnace. The pipe of the pipes of the rotary distributor pour out materials onto circles inside the blast-furnace. The material falling on top of the stack shows a section in M, or in 2M or in 3M.

d. As soon as the bin is empty, the lower valve shuts after the extractor has stopped. The different operations previously explained begin another cycle as in a).

3. When one assembly of the system is at stage a), the other assembly is at stage c) so that the rotary distributor is almost all the time loaded with materials and turns without any interruption. The loading level can be determined outside the circle swept by the biggest pipe or by any other means as TV camera for infra-red, echo-sound, radiation measurement level. The time wasted is limited to compression or decompression periods of the materials storage bins.

4. If the loading system in M is made with the present equipments of blast-furnace, the loadings in 2M and in 3M are only possible when using a rotary distributor with separated conical shapes, each with its outlet pipe. If there are two concentric separated conical bins there is a need for four storage bins and two outlet pipes. If there are six sets of storage bins, there are three concentric conical bins and three outlet pipes for discharge of materials inside the blast-furnace. A greater number will not be needed because the possibilities of diversifying the materials loads are numerous enough with the 3M system.

5. It is comparatively easy, in a short time, to shift from a loading system in 3M to a system in 2M. One needs only to stop 2 sets of bins. In the same way, one can shift from a loading in 2M to a loading in M. One can come back to a loading system in 3M from a loading system in 2M. In the same way, the transfer may be from a loading in M to a loading in 2M.

6. During a short slowing down, it is possible to add two sets of bins and to shift from a system in M to a system in 2M, from a system in 2M to a system in 3M. The longest modification is the exchange of the rotary distributor which, it seems, can be done during a very short stoppage of the blast-furnace, these transformations must be foreseen during construction by setting of a sealing ring for a greater roller bearing. This possibility is a security which can lead to a better use of the blastfurnaces, regarding the available materials and the percentage of ore and sintered pellets, the quality of coke and also regarding the enrichment of the hot blast with oxygen.

7. The time of the working cycles for each set can be modified and regulated, according to technological needs, from the results of various optimization and development experiments, not only about the loading parts of the furnace, which are comparatively easy to modify but also about the various other equipments such as cowpers, cooling of blast-furnace shell, the cast house, the shell, the refractories, the turbo-blowers and also the dust-catchers.

8. The number of combinations for the various loadings is nearly infinite and that is why a high automation level with the use of an industrial process computor would allow the printing of a very precise checking diary about the many parameters and effective programming of the blast-furnace loading, on which particularly depends the pig iron production.

9. The loading system in 3M has for its main purpose, the making, in the center of the blast-furnace, of a column of materials which could increase the heat energy and the reduction gas for process, could raise the inside temperature, especially in the stack and bosh axes, far from the refractory walls and from the cooling of the blast-furnace shell. To spare the very expensive coke, the use of prepared coal or anthracite directly inside the central column would reduce the coke consumption. The central column would be divided by thin layers of other additions for instance flux or limestone, or pellets.

10. The booking of loads, which are very common in classical furnaces will be almost eliminated by loading in 2M or in 3M, because the contact surfaces between outer and inner layers of materials facilitate slidings and relative movements of the different blocks of load, specially in the stack, the slower ones being along the walls, as protection and lubricant, the faster ones in the center.

1 l. The counter-pressure in the throat can easily be increased because the tightness of the valves is excellent and lasting during years. One must rather try to improve the development of the other elements of the blast-furnace to go into higher pressures.

12. The loading system being lightened, it will again be possible to avoid the construction of gigantic square superstructures and to have on the shell the possibility to carry the whole loading equipments. The gas uptakes could be used as carrying pillars for the storage bins and other elements of the loading systems in M, in 2M or in 3M.

An historical account of the evolution in blastfurnace is also the record of a slow progress up to 1950, followed by a quick evolution since then, the increase in the productivity of blast-furnaces being marked by stages which always are inventions such as the shell, skip-cars, MacKee bells, fuel oil injection, cooling of the hearth, etc. But unfortunately there is a tendency now to increase excessively the dimensions of standard equipments which have stood the test of time rather than looking for new solutions. The system in M, 2M and 3M may be a solution for the very numerous problems which results from the necessity of technical progress in the construction of blast-furnaces.

The characteristics and the advantages of the systems in M, 2M and 3M of the loading of a blast-furnace with a very high counter-pressure result from the descriptions which follow, as examples referring to the enclosed drawings in which:

FIGS. 1, 2 and 3 cross-sections views of a blastfurnace respectively having a loading in M, 2M and 3M.

FIG. 4 is an enlarged section of a blast-furnace having a loading in 3M.

FIG. 5 is a schematic view of a construction according to the invention.

FIGS. 6, 7 or 8 respectively show loading assemblies in M, 2M and 3M, and

FIGS. 9 and 10 are sectional views of equipments for the loading in 2M and 3M.

FIG. 1 is a cross-section of a schematic profile and the loading in M of a blast-furnace in which 1 is the blast area of combustion, 2 the slag volume, 3 liquid pig iron, 4 a layer of coke, 5 a layer of sintered pellets, 6 various additions such as limestorne, manganese or iron ores. This loading section in M is also called loading as ring by blast-fumaces specialists (in FRANCE). This term -M- seems better for an idea as the one described, because these letter pictures the loading line in the blast-furnace better.

FIG. 2 is also a diagrammatic section, representing a load in 2M in a blast-furnace. The 1 to 6 reference marks are as in FIG. 1 and the remarks are the same, but there is a clear distinction of the separation line between inner and outer loads, a conical shaped surface which makes the hooking more unusual and easier the slidings of materials to be turned into pig iron.

FIG. 3 is a third diagrammatic section showing the section or 3M profile of the loading level in a blastfurnace. The 1 to 6 reference marks are the same as in FIG. 1 and remarks about FIG. 1 and 2 can be taken into account also for FIG. 3. A distinctive feature is represented by 7 showing a column of prepared materials: these could be coke but also coal or anthracite. The purpose of this mass is to increase the quantity of reducing gases highly, to reduce the coke consumption by use of coal and to raise the temperature level in the axis of the blast-furnace, very far from the refractory layer. This version of loading in 3M should find an application in blast-furnaces of more than 4,000 m of useful volume, in which the inner diameter of the hearth exceeds 14 meters.

FIG. 4 is an enlarged section of the loading profile in a blast-furnace as 3M, with reference 4 representing coke, 5 sinter pellets and 6 various additions. The laying out of the layers of materials which go down into the stack of a blast-furnace is represented from hypothesises which are still very difficult to check. If the phenomenons which take place now in the blastfurnace are not entirely explained, the idea which is the aim of the invention, is a very important anticipation characterized by FIG. 4. There are numerous possible combinations for loading with system 3M, and this system opens a new path for the pig iron metallurgy.

. FIG. 5 represents a construction drawing which is rather schematized because the loading system in M is the basis for system 2M and system 3M. This section shows in 5 a sinter pellets layer, in 6 various additions. The materials to be loaded are brought by a conveyor 8, fall in the two ways duct 9, which guides them into the storage-bin 12, the swing-valve 10 being open and the tightness surfaces not subjected to wear. The rotary extractor 14 is stopped and the lower swing-valve l6 shut and very light, bearing its seat by very high counter-pressure in the throat of the blast-furnace. Storagebin 12 is in the loading stage, the upper swing-valve 11 is shut and bears upon its seat by means of the counterpressure in storage-bin 13 in unloading stage in the blast-furnace. The rotary extractor turns unclockwise, and it reduces to a minimum the wear of the carter. Swingvale 17 is open and the materials fall into the spout of the rotary distributor 18 which turns with a speed of X 30 r.p.m. and facilitate a regular distribution of the load, by means of a single weir pipe 19, cooled by water circulation in a water-jacket. The rotary distributor bears upon a gas tight ring which is rigidly locked to the throat 22, with an incorporated roller bearing. In is represented a motor element and 21 is a special bearing which allows for inlet and outlet of cooling water for the weir pipe 19, working under a surrounding temperature of 400 to 500 C. The blastfurnace gases go out by the gas uptake pipes 23 which are also used as construction pillars for

hoppers

12 and 13. As these must resist very high pressure and temperature, the shape of two half-cylinders having a common middle wall seems the best solution. The putting in pressure of hopper 13 is done by the use of the threeway valve 24 and the decompression of gases in hopper 12 is done by the three-way valve 25. The four-way valve 26 does the same work for

rotary extractors

14 and 15. The chronological order of work and the dephasing is explained in full details in page 3, a, b, c, and d FIG. 6 shows a diagram of the loading system in M, with the materials conveyor in 8, or a skip-car, 9 is a two-way weir feeder, l0 and 11 the upper tightness swing-valves, one being open when the other is shut, 12 and 13 two hoppers, one being loaded when the other is unloading into the blast-furnace, l4 and 15 the rotary extractors, one being stopped when the other is functioning, 16 and 17 the lower tightness swingvalves, the first shut when the second is open. The rotary distributor 18 with its single weir pipe 19 unloads materials into the throat 22 of the blast-furnace. So when a set of

elements

10, 12, l4, 16 is at the stage of loading materials into the hopper, the other set of

elements

11, 13, 15 and 17 is loading the blast-furnace.

FIG. 7 represents a diagram of the loading system in 2M with the same references as previously in FIG. 6, with the same symbols and remarks for its functioning; the staggered parallel system of the 2 groups of 2 assemblies can be varied, according to the need of the blast-furnace job.

FIG. 8 diagram represents the loading system as 3M with the same references and the same symbols as in FIG. 6. This schematic view is aimed at showing the engineering of 2M and 3M systems from the 1M system,

in a better way.

FIG. 9 is a section view of loading system equipments for 2M, in which the double rotary distributor 27 is mainly shown because all the other elements drawn in FIG. 5 would only have added confusion to the understanding of the whole, if they had been shown. Then to understand fully the system 2M, one must by looking at FIG. 5 and at FIG. 7, and complete the FIG. 9 by drawing the four hoppers and other elements, or even better build a small model, with two weir pipes.

FIG. 10 shows a vertical section view of the lower equipments in loading system 3M, with 28 as a triple rotary distributor and three weir pipes. The arrows show the outflow of materials, and one of the circuits stands at stage compression-decompression of the 2 sets of materials hoppers. The preceding remarks for FIG. 9 also applies to FIG. 10.

I claim:

1. A blast-furnace and loading system therefor comprising:

a. a blast-furnace having upright walls and an upper throat area;

b. a loading system including a rotary distributor having a plurality of weir pipes extending into said 'throat area;

c. each of said weir pipes having a discharge opening, said discharge openings being disposed in radially staggered relationship relative to each other, the radially outermost discharge opening being spaced radially inwardly from said furnace walls a substantial distance;

. whereby said loading system may spread a plurality of different materials and may give to the materials in the blast-furnace a profile having a cross-section with a plural M configuration.

2. A system as recited in claim 1, wherein the radially innermost discharge opening is spaced a substantial distance from the axis of rotation of the rotary distributor to further facilitate formation of a material profile in the blast furnace having a cross-section with a plural M configuration.

3. A system as recited in claim 1 wherein:

a. said rotary distributor includes a plurality of concentrically disposed spouts, each spout communicating with one of said weir pipes;

b. a pair of inlets communicating with each of said spouts and means associated with each inlet for closing one inlet when the other is open, whereby, through alternate use of said inlets, material may be substantially continuously fed into the blastfurnace without loss of pressure.

4. A system as recited in claim 1 wherein said weir pipes are disposed in side-by-side, staggered parallel relationship.

5. A loading system for a blast-furnace comprising:

a. two rotary distributors;

b. two weir pipes, each communicating with one of said rotary distributors, said weir pipes being disposed in staggered parallel relationship;

c. two sets, each of which includes a pair of material hoppers communicating with said rotary distributor and a pair of valve means, each valve means being disposed between one of said hoppers and said rotary distributor;

d. one valve means of each pair blocking communication between one of said hoppers of said pair and one rotary distributor while the other valve of said pair is open, whereby one hopper may be filled while the other is discharged, whereby alternate filling and discharge of said pair of hoppers of each set effects a substantially continuous feeding of material into the blast furnace without loss of pressure.

6. A loading system as recited in claim 5 including three of said sets, three rotary distributors and three weir pipes, each weir pipe communicating with one of said rotary distributors, said weir pipes being disposed in a staggered parallel relationship.

7. A loading system as recited in claim 6, wherein said rotary distributors and weir pipes are adapted to spread materials inside a blast-furnace to give a M profile, said system further comprising means for alternatively modifying the system from a M profile, to 2M profile and 3M profile.

8. A loading system as recited in claim 5, wherein said pair f hoppers of at least one set each have a halfcylindrical cross-section with a common median wall.

9. A loading system as defined in claim 5 wherein each of said sets further comprises:

a. a feeding duct communicating with both hoppers of said pair;

b. a pair of upper-swing valves, each swing valve being associated with one of said hoppers of said pair for opening and closing communication between said feeding duct and said pair of hoppers of each set;

c. a pair of rotary extractors each of which is disposed between one hopper of said pair and one rotary distributor for controlling the flow of material from each hopper of said pair when its associated valve means is open.

Claims

1. A blast-furnace and loading system therefor comprising: a. a blast-furnace having upright walls and an upper throat area; b. a loading system including a rotary distributor having a plurality of weir pipes extending into said throat area; c. each of said weir pipes having a discharge opening, said discharge openings being disposed in radially staggered relationship relative to each other, the radially outermost discharge opening being spaced radially inwardly from said furnace walls a substantial distance; d. whereby said loading system may spread a plurality of different materials and may give to the materials in the blastfurnace a profile having a cross-section with a plural M configuration.

3. A system as recited in claim 1 wherein: a. said rotary distributor includes a plurality of concentrically disposed spouts, each spout communicating with one of said weir pipes; b. a pair of inlets communicating with each of said spouts and means associated with each inlet for closing one inlet when the other is open, whereby, through alternate use of said inlets, material may be substantially continuously fed into the blast-furnace without loss of pressure.

5. A loading system for a blast-furnace comprising: a. two rotary distributors; b. two weir pipes, each communicating with one of said rotary distributors, said weir pipes being disposed in staggered parallel relationship; c. two sets, each of which includes a pair of material hoppers communicating with said rotary distributor and a pair of valve means, each valve means being disposed between one of said hoppers and said rotary distributor; d. one valve means of each pair blocking communication between one of said hoppers of said pair and one rotary distributor while the other valve of said pair is open, whereby one hopper may be filled while the other is discharged, whereby alternate filling and discharge of said pair of hoppers of each set effects a substantially continuous feeding of material into the blast furnace without loss of pressure.

8. A loading system as recited in claim 5, wherein said pair of hoppers of at least one set each have a half-cylindrical cross-section with a common median wall.

9. A loading system as defined in claim 5 wherein each of said sets further comprises: a. a feeding duct communicating with both hoppers of said pair; b. a pair of upper-swing valves, each swing valve being associated with one of said hoppers of said pair for opening and closing communication between said feeding duct and said pair of hoppers of each set; c. a pair of rotary extractors each of which is disposed between one hopper of said pair and one rotary distributor for controlling the flow of material from each hopper of said pair when its associated valve means is open.