WO2006094370A1

WO2006094370A1 - Pressurized loading system for blast furnaces

Info

Publication number: WO2006094370A1
Application number: PCT/BR2005/000264
Authority: WO
Inventors: José Maximiano FURTADO
Original assignee: Furtado Jose Maximiano
Priority date: 2005-03-08
Filing date: 2005-12-21
Publication date: 2006-09-14
Also published as: EP1872073A1; BRPI0501206A; BRPI0501206C1

Abstract

The present invention concerns a pressurized loading system for blast furnaces by feeding solid particles by means of conventional belt or pipe belt conveyors (42) directly at the top of the furnace. The loading system including stock silos (19 - 24) and valves (13 - 18, 25 - 30) is dislocated from the top of the furnace to the plant floor leaving there only the rotating and seesawing system (48,51 ,52) for the distribution of the solid particles and the safety devices (55). The whole plant is kept at the same pressure as the furnace employing a special piping system (31 - 33). The stock silos (19 - 24) can be charged and discharged alternatingly by automatic operating of the valves (13 - 18, 25 - 30). Charging of the stock silos is effected by reversible belt conveyors (4 - 6). The whole system guarantees leak-tightness and the prevention of air pollution.

Description

PRESSURIZED LOADING SYSTEM FOR BLAST FURNACES

This present patent of invention is mentioned to a loading system for siderurgical blast furnaces or any furnace that needs or in which if it desires to effect the pressurized loading of solid materials, which can be carried in conventional belt conveyors, in pipe belt conveyors, or in scraper conveyors when the necessary inclination is greater than the allowed one for conventional or pipe belt conveyors.

The pressurized loading system is thus being called; therefore since silos of load preparation, until effective disposal of load inside blast furnace, all system is pressurized.

The pressurized loading system is detailed in this patent of invention for siderurgical blast furnace, considering pipe belt conveyor. Currently, the load of the blast furnace is prepared in proper siderurgical installations or thirds acquired. The basic raw materials are storage ore, pellets, mineral or vegetal coal, calcareous rock yard, and other raw materials yard, and sent by belt conveyors (or another way of solid conveyor) after being processed in coking plant, in sintering plant and in calcination units, to stock silos.

Each stock silo stores a specific raw material of blast furnace load. Apron feeders or belt conveyor installed in inferior discharge chute of stock silos dose load on one belt conveyor (or another way of solid conveyor), which has the function to carry load until loading system, situated in blast furnace top.

This loading system is composed, currently, in its majority, for one complicated mechanism of hoppers conjugated with bells (double bell loading system), or with sealing valves (bell less top loading system), located in top of blast furnace and, through alternating opening and closing (bells or valves), it allows that load be introduced into furnaces with reasonable leak-tightness, as per leaking blast furnace gases to atmosphere and maintenance of the chamber pressure in furnace top. The bell less top loading system allows a better sealing, a longer operation campaign, beyond other advantages.

A loading system by gravity was patented by ARMCO STEEL CORPORATION (the clear USA 858.778 in Sep 17, 1969), but we do not have information of its application in any siderurgical plant until today. In this system, blast furnace gas permeates in ascending movement since blast furnace top, through the load that is in descending movement (countercurrent), until reaching a chamber with atmospheric pressure, which is linked to some system of treatment, compression and gas storage from blast furnace. As this chamber is with atmospheric pressure or below one, it is not possible to gas permeating by itself through load into atmosphere, becoming fulfilled itself, thus, gas sealing, and allowing load introduction into the furnace. A great part of blast furnace gas is directed to gas cleaning and storage system with the same top furnace pressure.

As positive pressure is placed today around 2,5 manometer bar, height of load column may reach, in this system, a reasonable value, to allow load introduction into blast furnace.

The load transport system since stock silos until loading system has evolved (cable tramway, skips, etc), being that nowadays all modern furnaces use conventional belt conveyors, although demand bigger distances between stock silos and blast furnaces, bring innumerable benefits, as substantial atmospheric pollution reduction, lesser maintenance and greater campaign, as per other advantages.

The stock silos and belt conveyors, in their points of transference or discharge, are equipped, nowadays, with dust removal system, trying to diminish atmospheric pollution. Although these cares and devices, pollution provoked by a belt conveyor continues existing, therefore many particle materials fall from belt conveyor, as much for spilling as for return from belt conveyor, which can't finish all material unloading in chute loading system.

Several forms to distribute load with bigger homogeneity and control (primordial in a furnace regular operation) also had been object of diverse patents, all basing on loading system with double bell or in bell less top system. In this case, however, the best load distribution is gotten with the bell less top system, considering this, another one of its advantages. In bell less top system, the useful life of sealing valves is bigger than in double bell loading system. In consequence, this is the , most used system in modern furnaces, consisting, currently, in the new technique applied to pressurized loading system for blast furnaces.

The basic principle of this patent of invention is to remove loading system from blast furnace top, consisting of hoppers and valves, dislocating it to plant floor, adding, moreover, many other improvements and simplifications to introduce load into blast furnace. It will only remain in blast furnace top the rotating and seesawing system of load distribution and the necessary equipment to keep the safety of furnace in emergency cases.

This patent considers cloistering pipe belt conveyor and its accessories in a piping, leaving from load stock silos until blast furnace top. As per this system, blast furnace pressure will be kept and transmitted through piping, until stock silos, throughout all pipe belt conveyor. Auxiliary systems, object of this patent of invention, will propitiate a perfect blast furnace leak-tightness, carried through one simple form and less onerous than existing solutions. Pollution will practically be do not exist; therefore the piping that cloisters pipe belt conveyor will hinder particles leaking from the load into atmosphere.

Another aspect, which will be improved, is the simplification of load distribution equipment, which will propitiate a better load distribution; beyond minor and easier maintenance of parts exposed abrasive wear.

For above displayed, this patent has the objective to introduce a new concept in blast furnaces loading system, much simpler, safer, registering lesser installation, operation and maintenance costs, as a bigger operational campaign, with minor pollution, beyond other advantages and benefits, which will be evident in description that follows.

For effect of this patent, the loading process may be by opening and closing type knife valves (or another kind of valves), or by gravity, both propitiating one perfect blast furnace leak-tightness, hindering that existent gases formed in combustion occurred in its interior be launched into atmosphere, beyond keeping a positive pressure in blast furnace top. In system considered in this patent, this pressure can reach 4,0 bar or more. The using of this great pressure could be carried through or not, depending on possibilities and on benefits that this pressure increase may provide to blast furnace operation.

The belt conveyor that leaves stock silos until blast furnace top could be a conventional or a pipe belt conveyor. We recommend the pipe belt conveyor for following reasons:

❖ It is constructed with a light weighted structure, and consequently less onerous;

❖ It mainly diminishes most of fine particle pollution inside the cloistering piping;

❖ It promotes a bigger angle for conveyor ascension, allowing, thus, distance shortening between stock silos and blast furnace; ❖ It allows direct changes without transfer house, promoting a good improvement of installations layout;

❖ It allows to inject collected particles by stock silos dust removal systems directly into load is being carried to blast furnace, inside proper pipe formed by the strap of pipe belt conveyor, with insignificant particles dispersion;

❖ It allows to add other raw materials inside the proper pipe formed by the strap of pipe belt conveyor;

Considering above described advantages, we are able to find out the use of pipe belt conveyor, although it does not indicate impracticable the conventional belt conveyor use.

The system will be explained in clarity and detailed description as follows, and in Fig. 1, 2, 3 and 4. Fig. 1 represents longitudinal elevation of pressurized loading system for siderurgical blast furnaces. Apron feeders, situated under stock silos, feed directly the pipe belt conveyor, which carries the load until blast furnace top. In according to Fig. 1 and Fig. 2, it is observed that belt conveyors (1), (2) e (3) arrive to load stock silos proceeding from the sintering plant, cocking plant or calcinations units or yards storage, unload in reversible belt conveyors (4), (5) and (6), which feed, alternatingly, each one of two chutes (7) and (8), (9) and (10), (11) and (12), with each one of raw materials that form blast furnace load.

In fact, we are considering three raw materials, or either, pellets, sinter and coke. In case being necessary others raw materials, it will be necessary as much other sets of two silos (19) and (20), (21) and (22), (23) and (24), as each new raw materials, with its respective feeding belt conveyors, reversible belt conveyors, chutes and apron feeders. This patent does not objective the disposal technology of load inside blast furnace, but only its exactly introduction. Raw materials that form blast furnace load are unloaded in one or other chute to reversible belt conveyors (4), (5) e (6). When a silo is full with pellets, for example, pellets reversible belt conveyor is commanded to invert its rotation and feed pellets silo chute, which was empty. When unloading system is operating by closing and opening superior knife valves (13) and (14), (15) and (16), (17) and (18) and inferior knifes valves (25) and (26), (27) and (28), (29) and (30), while a silo is being loaded, the other one will be unloading, inverting its position when cycle finishes. If loading occurs by gravity, only a silo will be loaded and unloaded at the same time, being the other silo full, as stand by. As alternative, a silo with one raw materials may be operated by intermittent loading (opening and closing valves) and others raw materials with gravity loading, and vice versa. This guarantees a great operational flexibility to the system, which may be applied to improvement of load stratification inside the blast furnace.

To simplify this description, we are going to describe all process for "pellets" raw materials, considering that, for example, silos (23) and (24) as pellets silos. Description for other raw materials is identical, becoming unnecessary its repetition.

As said before, belt conveyor (3), proceeding from pellets yard storage, feeds reversible belt conveyor (6) that alternatingly unloads in the chutes (11) or (12) of the silos (23) or (24), depending solely on rotation direction of reversible belt conveyor (6). Pellets fall inside chute by gravity, and are directed to pipe connected to them and their corresponding silos. In these pipes, superior knifes valves (17) and (18), with hydraulically drive, are installed. When chute (11) is being fed, knife valve (17) will be opened to allow pellets transference to the interconnection pipe between this chute and silo (23), and the knife valve (29) will be closed to hinder airflow rate to atmosphere. Completing this silo loading, the reversible belt conveyor inverts its rotation and it is initiated silo (24) loading through chute (12), opening knife valve (18). Soon after rotation inversion of reversible belt conveyor (6), knife valve (17) must be closed. As load material is abrasive, all parts in contact are coated with resistant material to abrasion. Knifes valves will be protected from abrasion, when opening or closing, by compressed air injection for seats cleanness, as much in its superior part as in its inferior. Moreover, they will have special construction to be protected from abrasion proceeding from descending pipes load, as knives and seats are made of resilient material. Fig.3 shows the constructive detail, as much as air injection as withdrawn position where it is pointed out the seat and the knife, protected by resistant material to the abrasion (62), which coats internally chutes, interconnection pipes between chute and silos, as well as proper silos, which hinders abrasion in all knifes valves, since all of them are built in identical way.

To still increase knifes valves protection, load-descending pipes are constructed with a small coning in descending direction. This coning also hinders load hanging in its interior.

When silo (23) loading is finished, silo (24) loading initiates, inverting reversible belt conveyor (6) rotation, initiating another identical operational sequence to the described above for silo (23). When silo (24) load is finished, the true blast furnace load initiates. Procedure is to command knife valve (55) opening, situated after pipe belt conveyor (42) superior drum, as well as its start, and, afterwards, start of apron feeder (36) chute rotation system and rotating seesawing distribution (52), (48) and (51), and only after those procedures, it is commanded opening inferior knife valve (30), beginning pellets raw material loading process. When loading occurs by gravity, superior knife valve (18) must be opened W

and reversible belt conveyor will continue loading silo (24), at the same time is being unloaded.

Is loading option is by gravity; it is necessary to inject compressed air in pipe (33), by opening pressure control valve (39). This valve has the function to keep apron feeders and pipe belt conveyor pressure, similar to the desired pressure in blast furnace top. Airflow rate will be in such way bigger as material permeability, which is being loaded per each raw material silos. Considering this loading system, pellets silo (24) may load indefinitely blast furnace with pellets, without opening or closing superior and inferior knife valves. Finished pellets loading, pellets supply is interrupted, stopping belt conveyors (3) and (6), and superior knife valve (18) closing is commanded. Inferior knife valve (30) may remain opened.

When loading option is by opening and alternating closing superior and inferior knife valves, both pellets silos must be alternating loading and unloading. In this case, before initiating silo (23) loading, it is necessary that pressure equalization of both silos be similar to blast furnace top pressure, through pinch valve (65) opening - see figure 2 -, which establishes silos (23) and (24) connection, previously closing superior knife valve (17). Thus, silo pressure (24), which is empty and pressurized, pressurizes the silo (23), allowing its unloading. Procedure is, then, to open inferior knife valve (29) to initiate furnace loading through silo (23). To load silo (24), it must be opened, slowly, superior knife valve (18) in way to depressurize silo into atmosphere, after inferior knife valve (30) have been closed, which may have pneumatic or hydraulically drive. The cycle is completed, through silo (24) being wadded and unloaded, processing they are restarting with silo (23) wadding.

Opening or closing any superior or inferior knife valves must always be accompanied by a compressed air injection in their seat, before and during their movement, to carry through particle cleanness proceeding from blast furnace load.

Knife valve (55) does not require none of theses cares, therefore it will be operated in emergency case. However, for its closure, it is necessary stop loading system of any silo, that is, all apron feeders and pipe belt conveyor (42) must be stopped while it is being closed, thus remaining even after its opening.

In order to prevent intense abrasion and shocks of load with load stock silos shell, in all wadding beginning, it must be placed some baffle plates (56) thru (61) in inferior silos shell cones. These baffle plates will hold back part of load, allowing that a protector inferior cone plate mattress be formed. In order to allow protective mattress formation, inferior cones have anti-symmetrical construction, as shown in Fig. 2. This anti-symmetrical construction will hinder, also, that knife of the inferior knife valves suffer direct impact from load falling since superior conical pipe. In way loading system occurs by gravity, these inconveniences will be minimized, since silos will be always full during normal operating periods.

As said before, basic objective of present patent of invention is to remove loading system from blast furnace, formed by hoppers and valves, from its top, dislocating it to plant floor. Pipes (31), (32), (33), (40) and (41) establish connection from blast furnace top to stock silos. In their whole way, they do not allow gases and solids leaking, annulling all possibility to pollute atmosphere. Existing pressure in blast furnace top is transmitted until conical pipe which unloads in apron feeders (34), (35) and (36). If inferior knife valve is opened, and superior knife valve of this exactly silo is closed - which may happen with any silos - blast furnace top pressure will reach whole silo and superior knife valve. Therefore, all silos may be constituted in way to support blast furnace pressure.

If this loading occurs by gravity, it will happen a pressure loss since beginning of inferior conical pipe - which is unloading in apron feeder - until superior load level inside silo, similar to blast furnace top pressure. The greater or lesser air pressure loss (supplied from external source) commanded by pressure control valves (37), (38) and (39) will guarantee that this pressure loss be similar to blast furnace top pressure. Apron feeder (36) pellets silo feeds pipe belt conveyor (42), which transports load to blast furnace. From there, load is launched in rotating chute (48) and from there in seesawing rotating distribution (51) inside blast furnace. This distribution processes a turn and a seesawing movement respectively commanded by turn system (52) and pneumatic cylinder (54). This cylinder has two functions. The first one is promote seesawing of the four tilting channel (51), and the second is to lift rotating chute set and delivering rotating and tilting channel to blast furnace maintenance position. In this position, it is possible to substitute channel tilting consuming plates and process chute (48) maintenance.

Channels tilting are made through cylinder (54) rod movement, which inclines four tilting channel to top, or to down, through bearing housing (45) and lever arms (44), as shown detailed in Fig 4.

Turn systems (52), made up of an electric motor and a gear reducer, makes possible rotation of composed set for chute (48) and rotating and seesawing distribution (51). The bearing housing support (53) has the function to support chute load and rotating and distribution set, besides through sealing to disable blast furnace gas leaking into atmosphere.

The bearing housing (50) allows centered rotation of the chute set and rotating and seesawing distribution. In this bearing housing nitrogen injection must be foreseen to disable the existing solid particle entrance in the gas of blast furnace and the unloaded load of the transporter of pipe belt conveyor (42).

As the hydraulic cylinder (54) has the function of seesawing the channels distribution and lifting all the chute set (48) and rotating and seesawing distribution (51), the connecting rod of the cylinder must go up and to go down without movement of turn inside guide pipe, to prevent turn of the connecting rod of the cylinder.

Sealing between the pipe and the connecting rod of the cylinder will have to be foreseen (54) to disable gas leaking from blast furnace to atmosphere.

Between both flanges (49), a goggle valve must be foreseen, in way to provide absolute sealing of blast furnace top, when some maintenance be carried through. A goggle valve may only be turned for the closed position after chute and rotating distribution and seesawing set survey, by cylinder (54).

After goggle valve closing, preceded by above described operations, furnace top could be set free to maintenance, since goggle valve allows the absolute sealing against gas leaking, and, thus, employees in maintenance charge will be able to work in the place, safely.

This lifting system of chute (48) and rotating and seesawing distribution (51 ) will provide easiness and a great maintenance safety, superior to current systems, for its simplicity, since there are not silos, closing valves or any complicated device on them.

Manhole (70) allows internal access to set.

Apron feeders (34), (35) and (36) have variable rotation, being able, therefore, to define feeding rate of load in blast furnace. Drive must be internal to pipes (31), (32) and (33), or external. In case its external, it must be foreseen sealing system to hinder compressed air leaking.

Pipe belt conveyor (42), with its maintenance platforms, will be fixed internally in pipe (40), being entire set laid in supports (67), distributed all long pipe belt conveyor, as structural necessity.

The reinforced belt of the pipe belt conveyor (42) will be kept stretched by belt stretcher (66). This belt stretcher may operate by counterweight, as shown in Fig 1 , or by spring. Pressure control valves (37), (38) and (39) will control compressed air injection into pipes (31), (32) and (33), to keep internal chamber pressure of pipes and to hindering pressure loss in blast furnace top. Concentration probe (43) of oxygen concentration (02), contained in air, will act in control valve (46), when oxygen concentration inside pipe (40) near of probe (43), reaches a value above of allowed one, through nitrogen injection inside pipe (40).

Control valve (46) has also the function to inject nitrogen inside pipe (40), every time:

❖ carbon monoxide concentration (CO) reaches a level above allowed one inside superior part of pipe (40), where CO concentration probe (47) is installed; ❖ the temperature close to temperature probe (68), which is located together belt conveyor superior drum, reaches one level above of allowed one for reinforced belt material;

❖ in operation beginning, pipe (40) being empty, filling it in nitrogen and keeping it full during whole period system is operating, hindering that blast furnace gas reaches inferior pipe (40) parts. In extreme emergency fact, as, for example, breakout of one of pipes (31), (32), (33) or (40), knife valve (55) must be automatically closed, by hydraulically or pneumatic force, when pressure inside pipe be below of one established value as minimum. This knife valve (55) is interlocked with rotation of pipe belt conveyor superior drum (42), or either, its closing only be allowed when drum is stopped.

In way to clean pipe (40), one or more cleanness points (69) must be installed all its way long, in places where it is verified more dust and/or solids. In these points (69) two knife valves may or not be installed, which will allow cleanness without stopping pressurized loading system.

Pipe belt conveyor (42) will be set in motion by superior drum, and it does not need speed variation. This patent of invention - Pl - has as purpose to surpass art state which exists currently, in following points:'

❖ reduction of blast furnace total height, caused by hoppers and loading mechanisms elimination in blast furnace top;

❖ reduction of loads and lifting load systems in blast furnace top;

❖ loads reduction on structure and blast furnace foundations;

❖ lesser implantation cost; ❖ lesser pollution due to inexistence of blast furnace gas leaking into atmosphere;

❖ system with more single operation;

❖ system with lesser operational cost;

❖ system with less maintenance; ❖ system with lesser maintenance cost;

❖ system with bigger operation campaign;

❖ system with bigger operational safety;

❖ Possibility of being carried through blast furnace load feeding, since stock silos, by proper PRESSURIZED LOADING SYSTEM, which is not possible in any current loading system, which always demands silos at plant floor and at blast furnace top.

Claims

1 ) PRESSURIZED LOADING SYSTEM FOR BLAST FURNACES" is a loading system for siderurgical blast furnaces or any furnace that needs or in which if desires to effect the pressurized loading of solid materials, which can be carried in conventional belt conveyors, in pipe belt conveyors, or in scraper conveyors, when the necessary inclination is greater than the allowed one for conventional or pipe belt conveyors, characterized for removing loading system from blast furnace, formed by hoppers and valves, from its top, dislocating it to plant floor, adding, moreover, many others improvements and simplifications to introduce load into blast furnace. It will only remain in blast furnace top the rotating and seesawing system of load distribution and the necessary equipment to keep the safety of furnace in emergency cases. 2) PRESSURIZED LOADING SYSTEM FOR BLAST FURNACES, in accordance with the claim in.1, characterized by propose cloistering of the pipe belt conveyor and its accessories in a piping, leaving from load stock silos until blast furnace top. As per this procedure, blast furnace pressure will be kept and transmitted through piping, until stock silos, throughout all pipe belt conveyor; auxiliary systems, object of this patent of invention, will propitiate a perfect blast furnace leak-tightness, carried through one simple form and less onerous than the existing solutions; so that pollution will practically be do not exist, therefore the piping which cloisters pipe belt conveyor will hinder particles leaking from the load into atmosphere and will simplify loading distribution equipment, which will propitiate a better load distribution; beyond minor and easier maintenance of parts exposed abrasive wear.

3) PRESSURIZED LOADING SYSTEM FOR BLAST FURNACES, in accordance with claims in. 1 and 2, characterized by allowing that loading process may be by opening and closing knifes valves (or another type of valves), or by gravity, both propitiating a perfect blast furnace leak-tightness, hindering that gases formed in combustion occurred in its interior be launched into atmosphere, beyond keeping a positive pressure in blast furnace top; as per system considered in this patent, pressure can reach 4,0 bar or more, depending on possibilities and on benefits this pressure increase may provide to blast furnace operation.

4) PRESSURIZED LOADING SYSTEM FOR BLAST FURNACES, in accordance with claims in. 1, 2 and 3, characterized for excusing hoppers; on blast furnace, only using a set of load stock silos, from which leaves pipe belt conveyor (42), being that belt conveyors (1), (2), (3) which arrive at load stock silos, proceeding from the storage yard, unloads in reversible belt conveyors (4), (5) and (6), which feed, alternatingly, one or another one of two chutes (7) and (8), (9) and (10), (11) and (12), with each one of raw materials which constitute blast furnace load; first at all, we are considering three raw materials, or either, pellets, sinter and coke; in case being necessary other raw materials, other sets of two silos (19) and (20), (21) and (22), (23) and (24) will be necessary as much for each new raw material, with its respective feeding belt conveyors, reversible belt conveyor, chutes and apron feeders; raw materials which form blast furnace load are unloaded in one or in another one of the chutes by reversible belt conveyors (4), (5) and (6); when a silo is full with pellets, for example, pellets reversible belt conveyor is commanded to invert its rotation and feed pellets silo chute, which was empty; when unloading process occurs by closing and opening superior knifes valves (13) and (14), (15) and (16), (17) and (18), and inferior knifes valves (25) and (26), (27) and (28), (29) and (30), while a silo is being loaded, the other one is being unloaded, inverting its position when cycle finishes; if loading occurs by gravity, only a silo will be loaded and unloaded at the same time, being the other silo full, as stand by; as alternative, it is possible to operate a silo with one raw material with intermittent loading (opening and closing the valves) and the other raw material by gravity loading, and vice versa. This guarantees a great operational flexibility to system. 5) PRESSURIZED LOADING SYSTEM FOR BLAST FURNACES, in accordance with claims in. 1 , 2 and 3, characterized for, in specific case of process for raw materials "pellets", considering that, for example, pellets silos as silos (23) e (24); as said before, belt conveyor (3) proceeding from pellets yard feeds reversible belt conveyor (6), which unloads, alternatingly, in chutes (11) or (12) of the silos (23) or (24), depending, solely, on rotation direction of reversible belt conveyor (6); pellets fall inside chute by gravity and they are directed to pipe which establishes connection with their correspondent silos; in these pipes, superior knife valves (17) and (18) are installed by hydraulically drive; when chute (11) is being fed, knife valve (17) will be opened, to allow pellets crossing by interconnection pipe between this chute and silo (23); completing loading of this silo, it is inverted reversible belt conveyor rotation and the silo (24) loading initiates through chute (12), by opening knife valve (18). Soon after rotation inversion of reversible belt conveyor (6), valve knife (17) must be closed. Finished silo (24) loading, it is commanded to open knife valve (55), start of apron feeders (36) and pipe belt conveyor (42), start of chute rotation system and of rotating and seesawing distribution (52), (48) e (51), and only after this procedure, it is commanded opening inferior knife valve (30), beginning raw materials pellets loading process; when load occurs by gravity, superior knife valve (18) must continue opened, so that reversible belt conveyor continues loading silo (24). The loading by gravity will be possible if it is injected compressed air in pipe (33), by opening pressure control valve (39); this valve has the function to keep pressure in cloistering pipes of apron feeders and of pipe belt conveyor, similar to desired pressure in blast furnace top; the air flow rate will be in such a way bigger how much bigger it will be the permeability of material which will be being loaded per item of raw materials silo; as per this loading system, silo of pellets (24) may load blast furnace indefinitely, without opening or closing superior and inferior knife valves; when pellets loading finishes, it is commanded closing superior knife valve (18).

6) PRESSURIZED LOADING SYSTEM FOR A BLAST FURNACES, in accordance with claims in. 1, 2, 3 and 5, characterized for, in specific case of process for raw materials "pellets", when loading option is by opening and alternating closing superior and inferior knife valves, the two silos of pellets must be loaded and unloaded alternatingly; in this case, before initiating silo (23) loading, it is necessary that pressure equalization of the two silos be similar to pressure of blast furnace top, through opening pinch valve (65) - see figure 2 -, which establishes connection of the two silos (23) and (24), closing previously superior knife valve (17); thus, silo pressure (24), which is empty and pressurized, pressurizes silo (23), allowing that it may be unloaded; it is commanded, then, opening inferior knife valve (29), to initiate furnace loading through silo (23); to load silo (24), it is necessary to open, slowly, superior knife valve (18) in way to depressurize silo into atmosphere, after inferior knife valve (30) have been closed, which may have pneumatic or hydraulically drive; after wadding and unloading silo (24), cycle is completed, being restarted with wadding of silo (23); opening or closing of any superior or inferior knife valves must always be accompanied by a compressed air injection in their seats, before and during their movement, to carry through particle cleanness proceeding from blast furnace load.

7) PRESSURIZED LOADING SYSTEM FOR A BLAST FURNACE, in accordance with the claims in. 1, 2, 3, 5 and 6, characterized for, in case that specific of the process for raw material "pellets", being that knife valve (55) does not require none of these cares, therefore it will only be operated in emergency case; however, so that it is closed, it is necessary to stop the loading system of any silos, that is, all the apron feeders and the pipe belt conveyor must be motionless, before it is being closed, thus remaining even after its opening; to prevent intense abrasion and shocks of the load with the shell of silos of load preparation, in all wadding beginning, baffle plates (56) thru (61) will be placed in inferior cone of silos shell; these baffle plates will hold back part of the load, allowing that it forms a protective mattress of the plate of the inferior cone; to allow formation of protective mattress, inferior cones have anti-symmetrical construction, as shown in the Fig. 2; this anti-symmetrical construction will hinder, also, that the knives of

5 inferior knife valves suffer direct impact from the load, falling since the superior conical pipe; with the loading system by gravity, these inconveniences will be minimized, since the silos will be always full during the period of normal operation. 8) PRESSURIZED LOADING SYSTEM FOR A BLAST o FURNACE, in accordance with the claims in. 1, 2, 3, 4, 5, 6 and 7, characterized for, in specific case of this patent, whose basic principle is to remove loading system of blast furnace from its top to plant floor, respective pipes (31), (32), (33), (40) and (41), which establish connection from top of blast furnace to raw materials silos; 5 in their entire passage, they do not allow gases and solids leaking, annulling, totally, possibility of polluting atmosphere; existing pressure in top of blast furnace it is transmitted until a conical pipe, which unloads in apron feeders (34), (35) and (36); if inferior knife valve is opened, and knife valve of this exactly silo is closed - which o may happen with any silos - pressure of blast furnace top will reach whole silo and superior knife valve; therefore, all silos must be constructed in way to support blast furnace pressure; in case loading is by gravity, it will have a pressure loss since beginning of conical pipe, which is unloading in apron feeder, until superior level 5 of load inside silo, similar to pressure of blast furnace top; The guarantees that this load loss is similar to pressure of blast furnace top will be greater compressed air or lesser air flow rate (supplied of external source), commanded by pressure control valves (37), (38) and (39); apron feeder (36) of pellets silos feeds pipe belt conveyor (42), and carries load to blast furnace; from this belt conveyor, the load is launched in a rotating chute (48), and from there in rotating seesawing distribution (51) inside blast furnace; this distribution has a movement of commanded turn and seesawing movement, respectively, by a turn system (52) and a pneumatic cylinder (54); this cylinder has two functions, the first one is to promote seesawing of four seesawing channel (51) of distribution, and the second one is to lift set rotating chute and rotating and seesawing distribution to the position of blast furnace maintenance; in this position it is possible to change seesawing channel consuming plates and to make maintenance in chute (48); the channel seesawing is made through the movement of connecting rod of cylinder (54), which inclines the four seesawing channel for top or for low, through bearing housing (45) and lever arms(44), as shown in detail in Fig. 4; the turn system (52), made up of an electric motor and gear reduce, makes possible rotation of composed set for chute (48) and rotating and seesawing distribution (51); the support bearing house has the function to support the load of the chute and the rotating and seesawing distribution set, besides carrying through sealing to disable blast furnace gas leaking into atmosphere; the bearing house (50) allows the centered rotation of the chute and rotating and seesawing set; in this bearing house, nitrogen injection must be foreseen to disable existing solid particle entrance in blast furnace gas and in pipe belt conveyor (42) unloaded load; the hydraulically cylinder (54) has the function of seesawing channels of distribution and to lift entire chute set (48) and rotating and seesawing distribution (51). The connecting rod of cylinder goes up and down, without turning movement, inside pipe guides, therefore it is part of chute and rotating distribution set; it must be foreseen sealing between pipe and cylinder connecting rod, to disable blast furnace gas leaking into atmosphere; between the two flanges (49), one goggle valve must be foreseen, in way to provide the absolute sealing of blast furnace top, when some maintenance be carried through; this goggle valve may only be turned for the closed position after the survey of chute and rotating distribution and seesawing set; after closing goggle valve, preceded by described operations above, furnace top could be set free for maintenance, since the goggle valve allows the absolute sealing against blast furnace gas leaking, and, thus, employees in charge of maintenance will be able to work in the place, safely; this chute (48) system survey and rotating chutes (51) will provide an easiness and a great maintenance security, superior to current systems, for its simplicity, since there are not silos, closing valves or any complicated device; the manhole (70) allows internal access to the set; apron feeders (34), (35) and (36) have variable rotation, being able, therefore, to define feeding rate of load in blast furnace; drive may be internal to pipes (31), (32) and (33), or external; in case it is external, it must be foreseen sealing system, to hinder compressed air leaking; pipe belt conveyor (42), with its maintenance platforms, will be fixed internally in pipe (40), being the entire set laid in supports (67), distributed all long pipe belt conveyor, as a structural necessity; the rubber strap of pipe belt conveyor (42) will be kept stretched by belt stretcher (66). This extender may operate by counterweight, as shown in Fig.1, or by springs; pressure control valves (37), (38) and (39) will control compressed air injection into pipes (31), (32) and (33), to keep internal chamber pressure of pipes and to hindering pressure loss in blast furnace top. The concentration probe (43), system of oxygen measurement (O₂) contained in air, will act in control valve (46), when oxygen concentration inside pipe (40) reaches a value above of the allowed one, through nitrogen injection inside pipe (40) close to concentration probe (43); control valve (46) also has the function to inject nitrogen inside pipe (40), every time carbon monoxide concentration (CO) reaches a level above of the allowed one inside superior part of pipe (40), where CO concentration probe (47) is installed, and/or when close to temperature probe (68), which is located together the superior drum of belt conveyor reaches one level above of the allowed one for rubber strap material; in extreme emergency case, as, for example, pipes (31), (32), (33) or (40) breakout, knife valve (55) must be automatically closed, for hydraulically or pneumatic force, when pressure inside of pipe be below of one established value as minimum. This knife valve (55) is interlocked with the rotation of belt conveyor superior drum (42), or either, its closing will only be allowed when drum is stopped; for pipe cleanness (42), one or more cleanness points (69) must be installed, in places where more accumulation of dust and/or solids occurs. In these points (69), two knife valves may be installed or not, in series, which will allow cleanness without stopping pressurized loading system; pipe belt conveyor (42) will be set in motion by superior drum, and does not need speed variation.