JP2005213590A - Method for blowing solid fuel into blast furnace and blowing lance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for improving a combustion ratio of solid fuel blown into a blast furnace, when the powdery solid fuel such as fine pulverized coal and wood piece, is blown into the blast furnace, and to provide a blowing lance. <P>SOLUTION: When the solid fuel together with gas for carrier, are blown into the blast furnace 1 through the solid fuel blowing lance 4 set in a blowing tube 5 connected to a tuyere 6, a nozzle is set toward a tangent line direction to the inner wall surface of the solid fuel blowing lance and the gas is supplied toward the tangent line direction of the solid fuel blowing lance through this nozzle, and the solid fuel together with the gas for carrier, are blown into the blast furnace while forming the circular stream of this gas. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a blowing method and blowing lance for pulverized solid fuel such as pulverized coal and wood chips, and more particularly to a blowing method and a blowing lance capable of improving the combustion rate of the injected solid fuel. Is.

  Blowing pulverized coal into blast furnaces is used in many blast furnaces because it has a large cost merit based on price differences from coke and heavy oil, and contributes greatly to improving economic efficiency. In recent years, the importance of coke ovens has been reaffirmed from the standpoint of extending the life of coke ovens, and more and more pulverized coal has been increasingly injected.

  The pulverized coal is generally blown into the blow pipe together with the transfer gas through a blow lance installed in the blow pipe for supplying hot air into the blast furnace, and then the blow pipe is heated together with the hot air passing through the blow pipe. It is blown into the blast furnace from the tuyere connected to the tip. The pulverized coal that has been blown is burned in a combustion space called a raceway in the blow pipe and at the tip of the tuyere, and substitutes for coke. However, since there is a large amount of coke on the raceway, the oxygen concentration in the hot air decreases rapidly. Moreover, since the gas flow velocity in the blow pipe and tuyere is generally very high at 200 m / sec, the time during which the blown pulverized coal can react with oxygen in the hot air, that is, the time during which the pulverized coal can be burned is extremely short. , About 20 microseconds.

  In order to effectively use pulverized coal as an alternative to coke, it is necessary to burn pulverized coal in this short period of time, but as the amount of pulverized coal increases, the combustion rate of pulverized coal decreases. The pulverized coal cannot be burned up to the raceway and remains in the furnace as unburned unburned char. This unburned char is consumed in the furnace due to the solution loss reaction, but there is a limit value for the amount of consumption in the furnace. If the unburnt char is accumulated in the furnace core or the molten zone, the air permeability and liquid permeability are hindered, resulting in instability of the furnace and a decrease in productivity.

In order to solve this problem, many methods for improving the combustion rate of pulverized coal have been proposed. For example, Patent Document 1 discloses a concentric double pipe on the side wall of a blow pipe in order to improve the mixing efficiency of hot air and pulverized coal in the blow pipe, and to increase the heating rate of the pulverized coal and thus increase the combustion rate. A method is disclosed in which a plurality of blow lances having a structure are provided, pulverized coal and a conveying gas are blown from between the inner pipe and the outer pipe of the blow lance, and air, oxygen or a mixed gas thereof is blown from the inner pipe. . In Patent Document 2, in order to improve the combustion rate of pulverized coal by using the combustion heat of auxiliary fuel, the temperature of hot air supplied from the blow pipe is adjusted to 810 ° C. or more, and in parallel with the pulverized coal blowing lance. A method of injecting pulverized coal by disposing a fuel gas injection tube and mixing pulverized coal with fuel gas is disclosed, and Patent Document 3 similarly uses a combustion heat of auxiliary fuel. As an auxiliary fuel and oxygen are injected into a blow pipe provided with a pulverized coal injection lance, and the pulverized coal is injected into an atmosphere of 1400 ° C. or higher and an oxygen concentration of 21% or higher formed by combustion of the auxiliary fuel. A method is disclosed. According to Patent Documents 1 to 3, a high combustion rate can be obtained even in the operation of mass-injecting pulverized coal.
JP-A-8-157916 Japanese Patent Publication No. 1-289847 JP-A-8-269509

  However, the above prior art has some problems, and the main ones are as follows. That is, in Patent Document 1, as compared with a single pipe lance, although mixing of pulverized coal and hot air is promoted, it is difficult to say that it is sufficient, and there is a case where the temperature is not sufficiently increased and is blown into the furnace. . For this reason, the combustion rate of pulverized coal cannot be said to be sufficiently high, and there is room for further improvement. Moreover, in patent document 2, since pulverized coal is mixed with fuel gas after the front-end | tip part of a blowing lance, the heat-up timing of pulverized coal is overdue, and it may be blown into a furnace, without temperature rising enough. However, although the combustion rate of pulverized coal is not sufficiently high for using auxiliary fuel, there is room for further improvement. In Patent Document 3, although a high combustion rate is obtained, In addition, it is necessary to install an auxiliary fuel blowing pipe and an oxygen blowing pipe in addition to the arrangement of the pulverized coal blowing lance, and the facilities become complicated and there is room for improvement in terms of running cost.

  The present invention has been made in view of the above circumstances, and an object thereof is to blow pulverized solid fuel such as pulverized coal or wood chips into a blast furnace through a solid fuel blowing lance installed in a blow pipe. At the same time, it is to provide a blowing method and a blowing lance capable of improving the combustion rate of the injected solid fuel in the blast furnace.

  A method for injecting solid fuel into a blast furnace according to a first aspect of the present invention for solving the above-mentioned problems is as follows. Solid fuel is introduced into a blast furnace together with a carrier gas through a solid fuel injection lance installed in a blow pipe connected to a tuyere. When blowing, gas is supplied into the solid fuel blowing lance at the tip of the solid fuel blowing lance, and the solid fuel is blown together with the carrier gas while forming a swirling flow of the gas.

  According to a second aspect of the present invention, there is provided a method for injecting a solid fuel into a blast furnace. It supplies in the direction.

  A solid fuel blowing method into a blast furnace according to a third invention is characterized in that, in the first or second invention, the gas is preheated and then supplied into a solid fuel blowing lance.

  The method for injecting solid fuel into a blast furnace according to a fourth invention is characterized in that, in any of the first to third inventions, the gas is a fuel gas and an oxygen-containing gas.

  According to a fifth aspect of the present invention, there is provided a method for injecting solid fuel into a blast furnace according to any one of the first to fourth aspects, wherein the gas supply amount or the gas temperature is set to a solid fuel injection amount or a solid fuel transfer gas. It adjusts according to the supply amount of this.

  A solid fuel injection lance to a blast furnace according to a sixth aspect of the present invention is a solid fuel injection lance installed in a blow pipe connected to a tuyere and for injecting solid fuel into a blast furnace together with a carrier gas. The tip of the blowing lance is provided with a nozzle arranged in the tangential direction of the inner wall surface of the solid fuel blowing lance for blowing gas into the solid fuel blowing lance, from the nozzle into the solid fuel blowing lance. The supplied gas forms a swirling flow.

  A solid fuel injection lance for a blast furnace according to a seventh aspect of the present invention is a solid fuel injection lance installed in a blow pipe connected to a tuyere and for injecting solid fuel into a blast furnace together with a carrier gas. At the tip of the blowing lance, a nozzle arranged in the tangential direction of the inner wall surface of the solid fuel blowing lance for blowing fuel gas into the solid fuel blowing lance, and an oxygen-containing gas into the solid fuel blowing lance. Nozzles disposed toward the tangential direction of the inner wall surface of the solid fuel blowing lance for blowing, and the fuel gas and oxygen-containing gas supplied from these nozzles into the solid fuel blowing lance are swirling It is characterized by forming.

  According to the present invention, the solid fuel such as pulverized coal and wood chips supplied from the lance is dispersed in the blow pipe by the swirl flow formed by the gas supplied into the solid fuel blowing lance. Mixing with the hot air in the blow pipe is promoted, the sensible heat of the hot air available per unit mass of the solid fuel and the absolute amount of oxygen are increased, and the temperature rise rate and the combustion rate of the solid fuel are increased. The combustion rate in the blow pipe and the blast furnace of the fuel increases. As a result, it is possible to increase the amount of solid fuel such as pulverized coal and wood chips compared to conventional levels, reduce the amount of expensive coke used, and reduce the amount of solid fuel such as pulverized coal and wood chips. Even when the blowing amount is kept at the same level as the conventional level, the amount of coke used can be reduced by an amount corresponding to the increase in the burning rate of solid fuel such as pulverized coal and wood chips, which has an industrially beneficial effect. Brought about.

  In addition, when a fuel gas and an oxygen-containing gas are used as the gas forming the swirl flow, the solid fuel is heated by the combustion heat of the fuel gas, so that the combustion rate of the solid fuel can be further improved. . Moreover, since the fuel gas and the oxygen-containing gas are supplied into the solid fuel blowing lance, only the solid fuel blowing lance needs to be installed in the blow pipe, and the equipment is simplified and the handling becomes easy.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. 1 to 3 are diagrams showing an embodiment of the present invention. FIG. 1 is a schematic view of a blast furnace tuyere where a solid fuel blowing lance according to the present invention is installed, and FIG. FIG. 3 is a schematic view of the solid fuel blowing lance according to FIG. 2, and is a schematic view taken along arrow XX ′ of FIG.

  As shown in FIG. 1, tuyere 6 for sending hot air into the blast furnace 1 is installed on the side wall of the blast furnace 1. The tuyere 6 is supported by a tuyere receiver 8 and a large tuyere 7 installed through the blast furnace iron skin 2 and the refractory 3 and is connected to the blow pipe 5. The blow pipe 5 is connected to a hot stove (not shown), and air or oxygen-enriched air heated in the hot stove is supplied into the blast furnace 1 as hot air from the tuyere 6 via the blow pipe 5. The The temperature of the hot air is usually 1000 ° C. or higher, and may exceed 1300 ° C. when it is high.

  The blow pipe 5 is provided with a solid fuel blowing lance 4 according to the present invention for blowing a powdered solid fuel containing carbon such as pulverized coal or wood chips into the blast furnace 1, and a tip 4 a of the blow pipe 5 is gas from the blow pipe 5. It protrudes into the flow path and is installed in a guide pipe 9 installed in the blow pipe 5. FIG. 1 shows an example in which pulverized coal is used as a powdered solid fuel. In this case, the solid fuel blowing lance 4 is connected to a supply / conveying device (not shown) that supplies and conveys the powdered solid fuel by the carrier gas, and the powdered solid fuel is fed by the carrier gas. It is conveyed in the solid fuel blowing lance 4. As this supply / conveyance device, no special device is required, and a conventional supply / conveyance device composed of a solid fuel cutting device, a conveyance gas supply device, and the like is sufficient. The carrier gas is preferably a non-oxidizing gas such as nitrogen or an inert gas such as Ar gas in order to transport pulverized coal that is a combustible material.

  As shown in FIGS. 2 and 3, the solid fuel blowing lance 4 is composed of a double pipe composed of an inner pipe 12 and an outer pipe 13, and the inside of the inner pipe 12 is in the form of powder such as pulverized coal or wood chips. It becomes a conveyance flow path by the gas for solid fuel conveyance, and the gap between the inner tube 12 and the outer tube 13 is an inert gas such as air, oxygen, nitrogen, carbon dioxide gas, Ar gas, or a mixed gas thereof, or It is a flow path for fuel gas and oxygen-containing gas. FIG. 2 shows an example of supplying fuel gas and oxygen-containing gas. Boundary walls 12a and 12a are provided between the inner pipe 12 and the outer pipe 13, and even when the fuel gas and the oxygen-containing gas are supplied, the fuel gas and the oxygen-containing gas are mixed in the double pipe portion. It is supposed not to.

  And the slit which opens toward the tangential direction of the inner wall surface of the inner tube 12 for forming the swirl flow along the inner wall surface of the inner tube 12 is provided at the tip of the inner tube 12, respectively. , Nozzle 14 and nozzle 15. The outer tube 13 is provided with an inlet 10 and an inlet 11 for introducing the gas.

  As the gas blown from the introduction port 10 and the introduction port 11, air, oxygen, nitrogen, carbon dioxide gas, inert gas such as Ar gas, or a mixed gas thereof can be used. Further, a fuel gas such as LPG or coke oven gas may be used in combination with an oxygen-containing gas for burning the fuel gas.

  In the case of using an inert gas such as air, oxygen, nitrogen, carbon dioxide gas, Ar gas, or a mixed gas thereof, it is not necessary to blow from both the inlet 10 and the inlet 11; You may blow from. Accordingly, when supplying an inert gas such as air, oxygen, nitrogen, carbon dioxide gas, Ar gas, or a mixed gas thereof, either the introduction port 10 or the introduction port 11 may be provided at one place, and the boundary wall 12a. Is unnecessary, and the nozzle 14 and the nozzle 15 may be either one.

  When the fuel gas and the oxygen-containing gas are blown in combination, the fuel gas and the oxygen-containing gas may be supplied separately, or the fuel gas and the oxygen-containing gas may be mixed and supplied in advance. . When the fuel gas is not burned inside the outer pipe 13, the fuel gas is blown from one introduction port, the oxygen-containing gas is blown from the other introduction port, and the fuel gas and the oxygen-containing gas are separated at the boundary wall 12a. There is a need to. On the other hand, when the fuel gas previously mixed with the oxygen-containing gas is burned inside the outer pipe 13, the boundary wall 12a is unnecessary, and the fuel gas and the oxygen-containing gas are supplied from different inlets, and When burning inside the outer tube 13, the boundary wall 12a needs to be removed. It is necessary to consider the installation of the boundary wall 12a according to each condition. In FIG. 2, there are two slit-like nozzles for forming a swirling flow along the inner wall surface of the inner tube 12 of the solid fuel blowing lance 4. Depending on whether they are separated or mixed, the number may be one or three or more. Accordingly, the number of inlets installed will be changed. As the oxygen-containing gas, it is preferable to use air, oxygen-enriched air, pure oxygen, or the like.

  The gas that forms the swirl flow along the inner wall surface of the inner pipe 12 is supplied to the solid fuel blowing lance 4 after preheating in advance in order to increase the rate of temperature rise of the solid fuel and thus increase the combustion efficiency of the solid fuel. It is preferable.

  In FIG. 1, only one solid fuel blowing lance 4 is disposed in the blow pipe 5, but a plurality of solid fuel blowing lances 4 may be installed according to the amount of solid fuel blowing, Although the blowing lance 4 is installed in the guide pipe 9 connected to the blow pipe 5, the structure may be such that the solid fuel blowing lance 4 is directly attached to the blow pipe 5 without installing the guide pipe 9. Furthermore, the tip of the solid fuel blowing lance 4 is bent to match the axial direction of the blow pipe 5, but it is not always necessary to bend it.

  Using the solid fuel blowing lance 4 according to the present invention having such a configuration, the gas is supplied into the outer pipe 13 from the inlet 10 and the inlet 11 during the operation of the blast furnace 1, and the tip of the inner pipe 12 is Powdered solid fuel such as pulverized coal while blowing along the inner wall surface of the inner tube 12 through the nozzles 14 and 15 and forming a swirl flow along the inner wall surface of the inner tube 12 at the tip of the inner tube 12. Is supplied by a carrier gas. In this case, the operation and effect are slightly different depending on whether or not the fuel gas is used, and will be described separately below.

  First, the case where air, oxygen, nitrogen, carbon dioxide gas, inert gas such as Ar gas, or a mixed gas thereof is used without using fuel gas will be described.

  In this case, an inert gas such as air, oxygen, nitrogen, carbon dioxide, Ar gas supplied from the outer tube 13 of the solid fuel blowing lance 4 to the inside of the inner tube 12 through the nozzles 14, 15, or the like The gas composed of the mixed gas flows into the blow pipe 5 from the tip 4a of the solid fuel blowing lance 4 while forming a swirling flow along the inner wall surface of the inner pipe 12 and taking a part of the solid fuel into the swirling flow. To do. This swirling flow does not immediately disappear in the blow pipe 5 but is mixed while swirling in the hot air passing through the blow pipe 5. Since the solid fuel also flows out into the hot air on this swirl flow, it is supplied to the hot air while being dispersed in the swirl direction of the swirl flow.

  As a result, mixing of the solid fuel and hot air is promoted, the sensible heat of the hot air that can be used by the solid fuel per unit mass and the absolute amount of oxygen increase, and the heating rate and combustion rate of the solid fuel increase. The combustion rate from the solid fuel blow pipe 5 to the raceway increases. When the gas to be swirled is preheated, the combustion rate can be further improved by preheating the solid fuel with this gas.

  Thus, according to the present invention, since the combustion rate of solid fuel increases, it becomes possible to increase the amount of solid fuel blown in such as pulverized coal and wood chips from the conventional level, and to increase the amount of expensive coke used. Can be reduced. In addition, even if the amount of solid fuel such as pulverized coal or wood chips is kept at the same level as the conventional level, the amount of coke used is reduced by the amount corresponding to the increase in the combustion rate of solid fuel such as pulverized coal or wood chips. can do. That is, the fuel ratio can be reduced.

  Next, the case where fuel gas is used will be described. Even when the fuel gas is used, the fuel gas may or may not be combusted inside the outer tube 13 and will be described separately.

  First, the case where fuel gas is burned inside the outer tube 13 will be described. In this case, the fuel gas and the oxygen-containing gas supplied from the introduction port 10 and the introduction port 11 to the inside of the outer tube 13 are combusted inside the outer tube 13 by an ignition device (not shown). The combustion heat generated by this combustion is transmitted to the inner pipe 12, and the solid fuel and the carrier gas supplied into the inner pipe 12 are heated by the transmitted heat.

  Next, the high-temperature combustion exhaust gas generated by the combustion of the fuel gas and the oxygen gas is supplied to the inside of the inner tube 12 through the nozzle 14 and the nozzle 15 at the tip position of the inner tube 12. The combustion exhaust gas supplied from the outer tube 13 to the inner tube 12 through the nozzles 14 and 15 forms a swirling flow along the inner wall surface of the inner tube 12, and takes a part of the solid fuel into the swirling flow. The solid fuel blowing lance 4 flows into the blow pipe 5 from the tip 4a. This swirling flow does not immediately disappear in the blow pipe 5 but is mixed while swirling in the hot air passing through the blow pipe 5. Since the solid fuel also flows out into the hot air on this swirl flow, it is supplied to the hot air while being dispersed in the swirl direction of the swirl flow. As a result, the solid fuel is heated by direct contact with the high-temperature combustion exhaust gas, and at the same time, mixing of the solid fuel and hot air is promoted, and the sensible heat of the hot air and the absolute oxygen of the solid fuel per unit mass can be used. The amount increases, and the temperature rise rate and combustion rate of the solid fuel increase.

  Next, a case where fuel gas is not burned inside the outer tube 13 will be described. In this case, the fuel gas and the oxygen-containing gas are blown independently from the outer tube 13 into the inner tube 12 through the nozzle 14 and the nozzle 15. The fuel gas and the oxygen-containing gas supplied into the inner pipe 12 are mixed while forming a swirling flow along the inner wall surface of the inner pipe 12 and heated by hot air passing through the blow pipe 5 or an ignition device. To burn in a state where a swirl flow is formed. When the fuel gas burns, the gas inside the solid fuel blowing lance 4 is separated by the density difference, and gas layers having different densities are formed on both sides of the flame. That is, high-temperature combustion exhaust gas exists on the axis side where the turning speed is slow, and unburned gas exists on the inner wall surface side where the turning speed is high. In this case, since the swirl speed is higher than the flame propagation speed in the vicinity of the inner wall surface, the flame cannot continue to exist in the vicinity of the inner wall surface. Produced in a tubular shape. In the present invention, this flame is referred to as a “tubular flame”.

  The powdered solid fuel to be blown is heated by the tubular flame, and after being heated, as described above, the powdered solid fuel is dispersed in the swirling flow from the tip 4a of the solid fuel blowing lance 4 in the swirling direction in the hot air. Supplied. That is, the solid fuel is heated by the high temperature tubular flame, and at the same time, the mixing of the solid fuel and the hot air is promoted, the sensible heat of the hot air and the absolute amount of oxygen that can be used per unit mass increase, The heating rate of the fuel and the combustion rate are increased.

  By the way, in the case of a solid fuel that generates tar when heated, such as pulverized coal or wood chips, it accumulates inside the solid fuel blowing lance 4 and the blow pipe 5 due to this tar, and hinders smooth operation. Since there is a fear, it is preferable to heat the solid fuel in a temperature range in which tar is not generated. That is, since tar is generated at about 400 ° C., it is preferable to heat in a range of 350 ° C. or less. On the other hand, if the heating temperature is too low, the heating effect is reduced, which is not preferable. Therefore, it is preferable to determine the supply amount of the fuel gas supplied from the introduction port 10 or the introduction port 11 so that the powdered solid fuel to be blown becomes 200 ° C. to 350 ° C. The supply amount of the oxygen-containing gas may be a flow rate at which the fuel gas is almost completely combusted. However, the oxygen-containing gas may be added in an excessive amount, or a small amount of fuel gas may remain unburned.

  This problem due to the generation of tar does not use fuel gas, but also occurs when the inert gas such as air, oxygen, nitrogen, carbon dioxide gas, Ar gas or a mixed gas thereof is used by preheating. It is preferable to adjust the supply amount or temperature of these gases so that the powdered solid fuel does not exceed 350 ° C.

  For example, there are the following two methods for dealing with the problem of tar. One method is to supply the amount of gas and the amount of gas necessary for heating or raising the temperature within the predetermined temperature range, depending on the amount of solid fuel blown in, the specific heat and size of the solid fuel, and the flow rate of the transfer gas. Since the temperature differs, a heating test or the like is performed in advance, the necessary supply amount and temperature are grasped, and the supply amount and temperature are adjusted in accordance with changes in operating conditions of the blast furnace 1. In this case, the amount of solid fuel blown can be measured from a change signal per unit time of the solid fuel by a load sensor installed in a solid fuel storage hopper (not shown), for example. The supply amount can be measured by a flow meter.

  However, the actual operating conditions of the blast furnace 1 are as follows: the amount of solid fuel blown in, the amount of solid fuel transport gas supplied, the ratio of solid fuel to transport gas (solid-gas ratio) Since the type of solid fuel to be injected is variously changed, it is practically impossible to assume all the conditions in advance, and the above method may not be able to cope with it.

  On the other hand, in another method, the temperature of the atmosphere through which the solid fuel passes is measured online, and supplied from the inlet 10 and the inlet 11 so that the temperature of the atmosphere is 200 ° C. to 350 ° C. This is a method for adjusting the supply amount of the gas to be supplied and its temperature online. In this method, it is not necessary to carry out a heating test or the like in advance, and all operating conditions can be dealt with.

  Even if the supply amount of gas supplied from the introduction port 10 and the introduction port 11 and the temperature thereof are constant, it can cope with changes in operating conditions such as increase or decrease in the amount of solid fuel blown in or the amount of solid fuel transport gas supplied. Thus, the temperature of the atmosphere through which the solid fuel passes changes up and down. Therefore, the temperature of the atmosphere through which the solid fuel passes is continuously measured with a thermometer, and the supply amount or temperature of the gas supplied from the introduction port 10 and the introduction port 11 is adjusted according to the change state.

  FIG. 4 is a schematic diagram showing an example of a configuration for controlling the supply amount of the fuel gas and the oxygen-containing gas in accordance with the temperature of the atmosphere through which the solid fuel passes. As shown in FIG. 4, a thermocouple 16 a is installed in the blow pipe 5 near the tip of the solid fuel blowing lance 4, and a measurement signal of the thermocouple 16 a is input to the thermometer 16, and the thermometer 16 The temperature of the passing atmosphere is measured. The signal of the thermometer 16 is input to the temperature control device 17, and the temperature control device 17 determines whether or not the measured temperature is in the range of 200 ° C to 350 ° C. When the measured temperature is outside the range of 200 ° C. to 350 ° C., the temperature control device 17 adjusts the opening of the flow rate adjusting valve 18 to increase or decrease the supply amount of the fuel gas. The flow meter 19 measures the flow rate of the fuel gas and transmits the measured value to the flow control device 21. The flow rate control device 21 is a device that controls the flow rate of the oxygen-containing gas so that the ratio of the fuel gas / oxygen-containing gas becomes a predetermined value in accordance with the flow rate of the fuel gas. The supply amount of the oxygen-containing gas is controlled by adjusting the opening degree of the flow rate adjustment valve 22 according to the measured value of the total 19. The flow meter 20 is a device that measures the flow rate of the oxygen-containing gas, and the measurement result is input to the flow rate control device 21 so that the supply amount of the oxygen-containing gas is feedback-controlled. That is, on the basis of the temperature of the atmosphere through which the solid fuel passes measured by the thermometer 16 provided with the thermocouple 16a, the supply amount of the fuel gas and the oxygen-containing gas is adjusted online, and the temperature of the atmosphere through which the solid fuel passes Is controlled within a range of 200 ° C to 350 ° C.

  4 is a device for controlling the supply amount of the fuel gas. However, when the flow rate of the preheated gas is controlled, the output of the temperature control device 17 is supplied to the flow rate adjustment valve 22 simultaneously with the flow rate adjustment valve 18. This can be performed by controlling the opening degree of the flow rate adjusting valve 18 and the flow rate adjusting valve 22 with the temperature control device 17. The point is that the flow rate control valve 18 and / or the flow rate control valve 22 is used to control the flow rate, and the formed swirl flow is maintained at an appropriate temperature and flow rate (flow velocity). If it does, it is possible to exhibit a sufficient function only by the configuration of 16 to 19 in the figure. Further, when measuring the temperature of the atmosphere through which the solid fuel passes, the thermocouple 16a installed in the atmosphere may be worn by collision of the solid fuel, so that the temperature can be measured with excellent wear resistance and accuracy. It is preferable that the protective tube is installed inside a dedicated protective tube, and the protective tube is installed in an atmosphere through which the solid fuel passes.

  By the way, for example, when a gas not containing oxygen such as nitrogen, carbon dioxide gas, Ar gas at room temperature is supplied from the inlet 10 and the inlet 11, the solid fuel is supplied by the gas supplied from the inlet 10 and the inlet 11. When changing the amount of solid fuel blown in a state where only the swirling flow of these non-oxidizing gas or inert gas is formed without preheating, the solid based on the promotion of mixing of the solid fuel and hot air by the swirling flow Rather than the effect of increasing the combustion rate of the fuel, the combustion reaction caused by the contact between the solid fuel and the oxygen in the hot air is hindered by the swirling flow of non-oxidizing gas or inert gas, and these gases forming the swirling flow are Since the swirl flow is not preheated, the temperature of the atmosphere through which the solid fuel passes may decrease, and the solid fuel combustion rate may decrease. It is instead a kind of gas supplied from the inlet 10 and the inlet 11, to ensure the contact with oxygen of the solid fuel and hot air and it is desirable to ensure the temperature of the atmosphere passing through the solid fuel. For example, by detecting the oxygen concentration in the atmosphere in the swirling flow region and maintaining the temperature, the flow rate of the inert gas for swirling and the oxygen content are maintained so that the atmosphere in the swirling flow region has a constant oxygen concentration. It is also conceivable to mutually adjust the gas flow rate.

  By blowing solid fuel such as pulverized coal or wood chips into the blast furnace 1 in this way, the solid fuel is dispersedly supplied into the hot air by the swirling flow and further heated by the burned fuel gas. The combustion rate from the blow pipe 5 to the raceway increases, and as a result, the amount of solid fuel such as pulverized coal and wood chips can be increased from the conventional level, and the amount of expensive coke used can be reduced. Can be reduced. In addition, even if the amount of solid fuel such as pulverized coal or wood chips is kept at the same level as the conventional level, the amount of coke used is reduced by the amount corresponding to the increase in the combustion rate of solid fuel such as pulverized coal or wood chips. can do. That is, the fuel ratio can be reduced.

  The present invention is not limited to the above description, and various modifications can be made. For example, a flow path for circulating cooling water may be installed on the outer periphery of the solid fuel blowing lance 4, and two or more nozzles for supplying fuel gas and oxygen-containing gas may be installed. Furthermore, the solid fuel blowing lance 4 need not be a double pipe, and a gas supply flow path may be installed outside the inner pipe 12. In short, as long as a swirl flow along the inner wall surface of the solid fuel blowing lance 4 can be formed at the tip position of the solid fuel blowing lance 4, the structure may be any.

  Using the solid fuel blowing lance shown in FIG. 2, a test was conducted in which the solid fuel was blown into the blast furnace together with the fuel gas and the oxygen-containing gas in the blast furnace equipment having the configuration shown in FIG. The fuel gas and the oxygen-containing gas were supplied separately and supplied without burning inside the outer pipe of the solid fuel blowing lance. The solid fuel blowing lance is provided with a flow rate control facility shown in FIG. The target temperature of the solid fuel passage atmosphere in this test operation was set to 300 ° C.

As the solid fuel, a mixture of pulverized coal and wood chip powder obtained by pulverizing a piece of wood is used, pure nitrogen is used as a carrier gas, and the flow rate is 15 Nm ³ / hr, and a mixture of 700 kg / hr of pulverized coal and wood chip powder is used. Infused. LPG was used as the fuel gas, and air was used as the oxygen-containing gas. By setting the target temperature of the solid fuel passage atmosphere to 300 ° C., the supply amount of LPG was about 3.0 Nm ³ / hr, and the supply amount of air was about 72 Nm ³ / hr. Under this condition, the temperature of the passage atmosphere of the solid fuel was controlled to be constant at about 300 ° C.

During this test operation, due to changes in the operating conditions of the blast furnace, the flow rate of pure nitrogen, which is a carrier gas, remains constant at 15 Nm ³ / hr, and the blowing rate of the mixture of pulverized coal and wood chip powder is 400 kg / hr However, the LPG and air flow rates are controlled by the output signal of the temperature controller based on the measured value of the thermometer with the thermocouple installed near the tip of the solid fuel blowing lance. The opening degree of the valve was automatically adjusted, the supply amounts of LPG and air were automatically changed, and the temperature of the solid fuel passage atmosphere was controlled to a constant value of about 300 ° C. Incidentally, when the flow rate of pure nitrogen, which is a carrier gas, is 15 Nm ³ / hr, and the blowing rate of the mixture of pulverized coal and wood chip powder is 400 kg / hr, the supply amount of LPG is about 2.0 Nm ³ / hr, The supply amount was about 48.0 Nm ³ / hr.

  In this way, the mixture of pulverized coal and wood chip powder was continuously blown, unburned char in the exhaust gas discharged as dust from the furnace top was recovered, and the combustion rate of pulverized coal and wood chip powder in the blast furnace was calculated. For comparison, a test of blowing pulverized coal and wood chip powder was also performed using the method according to Patent Document 2 described above (conventional example).

  FIG. 5 shows the results of investigation on the burning rate of pulverized coal and wood chip powder in this test operation. As shown in FIG. 5, in the example of the present invention, the combustion rate increased by about 10% for both pulverized coal and wood chip powder as compared with the conventional example. In addition, the combustion rate shown in FIG. 5 represents that all of the pulverized coal and wood chip powder blown when the combustion rate is 1 burned.

  Table 1 shows the results of investigating the coke ratio between the present invention example and the conventional example, with the amount of pulverized coal blown constant at 200 kg per ton of hot metal. As apparent from Table 1, in the present invention example, the combustion rate of pulverized coal is higher than that in the conventional example, so the amount of coke corresponding to that amount is reduced, and the fuel ratio is reduced by 20 kg per ton of hot metal. I was able to.

It is the schematic of the blast furnace tuyere part in which the solid fuel blowing lance which concerns on this invention was installed. It is the schematic of the solid fuel blowing lance which concerns on this invention. It is the schematic by the X-X 'arrow of FIG. It is a schematic block diagram for controlling supply_amount | feed_rate of the gas which forms a swirl | vortex flow according to the temperature of the atmosphere which a solid fuel passes. It is a figure which compares and shows the combustion rate of pulverized coal and wood chip powder by the example of this invention, and a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Blast furnace 2 Blast furnace iron skin 3 Refractory 4 Solid fuel injection lance 5 Blow pipe 6 Tuyere 7 Large tuyere 8 Tuyere metal 9 Guide pipe 10 Inlet 11 Inlet 12 Inner pipe 13 Outer pipe 14 Nozzle 15 Nozzle 16 Thermometer 17 Temperature Control Device 18 Flow Control Valve 19 Flow Meter 20 Flow Meter 21 Flow Control Device 22 Flow Control Valve

Claims (7)

  When solid fuel is blown into the blast furnace together with the transfer gas through the solid fuel blowing lance installed in the blow pipe connected to the tuyere, gas is supplied into the solid fuel blowing lance at the tip of the solid fuel blowing lance. Then, the solid fuel is blown into the blast furnace with the gas for transportation while forming the swirling flow of the gas.   2. The blast furnace according to claim 1, wherein the gas is supplied in a tangential direction of the inner wall surface through a nozzle installed in a tangential direction of the inner wall surface of the solid fuel blowing lance. Solid fuel injection method.   3. The method for injecting solid fuel into a blast furnace according to claim 1, wherein the gas is supplied into a solid fuel injection lance after preheating in advance.   The method for injecting solid fuel into a blast furnace according to any one of claims 1 to 3, wherein the gas is a fuel gas and an oxygen-containing gas.   The gas supply amount or the gas temperature is adjusted according to a solid fuel blowing amount or a solid fuel carrier gas supply amount, according to any one of claims 1 to 4. A method for injecting solid fuel into the blast furnace as described.   A solid fuel injection lance installed in a blow pipe connected to the tuyere for injecting solid fuel into a blast furnace together with a carrier gas, and at the tip of the solid fuel injection lance, there is gas in the solid fuel injection lance. A nozzle disposed in a direction tangential to the inner wall surface of the solid fuel blowing lance, and the gas supplied from the nozzle into the solid fuel blowing lance forms a swirling flow. , Solid fuel injection lance to blast furnace.   A solid fuel injection lance installed in a blow pipe connected to a tuyere for injecting solid fuel into a blast furnace together with a carrier gas, and at the tip of the solid fuel injection lance, the fuel in the solid fuel injection lance A nozzle arranged in the tangential direction of the inner wall surface of the solid fuel blowing lance for blowing gas, and a tangential direction of the inner wall surface of the solid fuel blowing lance for blowing oxygen-containing gas into the solid fuel blowing lance A solid fuel injection into a blast furnace, characterized in that a fuel gas and an oxygen-containing gas supplied from these nozzles into a solid fuel injection lance form a swirl flow Lance.

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