JP6034313B2 - Combined lance for blast furnace tuyere - Google Patents

Description

  In the present invention, a solid reducing material such as pulverized coal and a gaseous reducing material such as LNG (Liquefied Natural Gas) are blown from the blast furnace tuyere to increase the combustion temperature and reduce the productivity. The present invention relates to a lance used in a method of operating a blast furnace to reduce the basic unit of material.

In recent years, global warming due to an increase in carbon dioxide emission has become a problem, and the suppression of exhausted CO ₂ is an important issue even in the steel industry. As a result, in recent blast furnace operations, the ratio of low reducing agent ratio (low RAR: Abbreviation for Reduction Agent Ratio, the total amount of reducing material blown from the tuyere and coke charged from the top of the furnace per 1 ton of pig iron production. ) Operation is strongly promoted. Blast furnaces mainly use coke and pulverized coal as reducing materials, and in order to achieve a low reducing material ratio, and thus carbon dioxide emission control, coke etc. have a high hydrogen content such as waste plastic, LNG, heavy oil, etc. It is effective to replace with a reducing material. At that time, the solid reductant, the gas reductant, and the combustion-supporting gas are simultaneously blown from the lance, so that the temperature of the solid reductant is increased by the combustion field of the gas reductant, thereby improving the combustion rate of the solid reductant. However, the generation of unburned powder and coke powder is suppressed, and it is said that the reducing material ratio can be reduced by improving the ventilation. In the following Patent Document 1, for example, the lance is a triple tube type, the innermost tube is the inner tube lance, the innermost tube and the second tube from the inside are the intermediate lance, and the innermost tube is the second tube from the innermost. An outer pipe lance is provided between the outer pipes, and each of the inner pipe lance, the intermediate lance, and the outer pipe lance is blown with a solid reducing material, a gas reducing material, and a combustion-supporting gas.

JP 2011-174171 A

  Incidentally, a lance guide tube is provided in a blower pipe (blow pipe) that mainly blows hot air to the tuyere, and the lance is inserted into the blower tube through the lance guide tube. However, as described in Patent Document 1, when the lance is a heavy pipe type and gas is blown from the gap between the pipes, there is a large pressure loss with respect to the flow rate of the gas. There is a possibility that the diameter of the lance is extremely increased and the lance cannot be inserted into the lance guide tube.

  The present invention has been made paying attention to the above-described problems, and provides a blast furnace tuyere lance capable of reducing the reducing material basic unit without extremely increasing the diameter of the lance. It is for the purpose.

In order to solve the above problems, a blast furnace tuyeres composite lance according to the present invention is a blast furnace tuyeres composite lance having three parallel flow paths through which solids or fluids flow. of constitute first one of the flow path, configured with a circular cross-sectional flow portion formed by a circular cross section of the tubular body, the second flow path of the three flow paths, the longitudinal cross section of the tubular body incomplete circular cross-sectional flow portion of the first one formed by combined contact the both end portions of the first one of the vertically divided tube the switching devoid sectional continuously in direction and arcuately to the circular section of the tubular body And one end of a second vertically-divided tubular body that constitutes a third flow path among the three flow paths and has a cross-section cut continuously in the longitudinal direction so that the cross-section has an arc shape. A second incomplete product formed by joining the tubular body having a circular cross section and joining the other end portion of the second vertically-separated tubular body to the first vertically-separated tubular body; And a circular cross-sectional flow portion and is characterized by being configured to set channel portion by said circular cross-sectional flow portion and the first one and incomplete circular cross-sectional flow portion of the second.

In the present invention, the two or more parallel flow paths through which solids or fluids flow indicate all those in which the flow paths do not cross each other and are independent, and the solids or fluids flowing through the respective flow paths flow in the same direction. . Further, the solid can flow through the flow path together with the carrier gas, and the carrier gas may have other functions such as a reducing gas.
In addition, a cooling fluid channel portion for cooling fluid for cooling the collective channel portion is provided.

In addition, an outer peripheral tube is provided on the outer periphery of the collective flow channel portion, and a gap between the collective flow channel portion and the outer peripheral tube body is used as the cooling fluid flow channel portion .

Further, any one of the three channels is a channel through which the solid flows, and two channels other than the channel through which the solid flows out of the three channels are channels through which the fluid flows, solid reducing agent supply means for supplying a solid reducing material is connected to the channel through the pre-Symbol solids, to one flow path is combustion supporting gas supply means for supplying a combustion-supporting gas flows before Symbol fluid It is characterized by being connected.
Further, characterized in that the gas reducing material supply means for supplying a gas material reducing material, the combustion supporting gas supply means is connected to any one other than the flow path of the flow path through which the fluid being connected It is what.

In addition, the first flow path among the three flow paths constituting the circular cross-sectional flow path constitutes a flow path through which the solid flows, and the solid reducing material supply means is configured by the circular cross-sectional flow path. It is connected to the flow path through which the solid flows.
A lance for a blast furnace tuyere having three flow paths through which a solid or a fluid flows, wherein the first flow path of the three flow paths is formed, and the first cross-section is circular. The first circular cross-section flow channel portion formed by the tube body and the second flow channel of the three flow channels are configured and joined to the first tube body and have a circular cross-section. A second circular cross-section channel formed by the second tube and a third channel among the three channels, and the cross-section of the tube is notched continuously in the longitudinal direction And an incomplete circular cross-sectional flow path portion formed by joining both ends of a vertically divided tubular body having an arcuate cross section to the first tubular body and the second tubular body, The first and second circular cross-sectional flow channel portions and the incomplete circular cross-sectional flow channel portion constitute a collective flow channel portion.
A lance for a blast furnace tuyere having four flow paths through which a solid or a fluid flows in a parallel state, the first of the four flow paths being configured, and the first having a circular cross section The first circular cross-section flow channel portion formed by the pipe body and the second flow path of the four flow paths are formed and joined to the first pipe body and have a circular cross-section. A second circular cross-section channel formed by the second tube and a third channel among the four channels are formed, and the cross-section of the tube is continuously cut in the longitudinal direction. A first incomplete circular cross-section flow formed by joining both ends of the first vertically-divided tubular body having a circular cross section to the first tubular body and the second tubular body. A second vertically-divided pipe that forms a passage and a fourth passage out of the four passages, and the cross-section of the tubular body is continuously cut in the longitudinal direction so that the cross-section has an arc shape. A second incomplete circular cross-section channel part formed by joining both ends of the first pipe body and the second pipe body, the first and second The aggregate flow path portion is constituted by the circular cross-section flow path section and the first and second incomplete circular cross-section flow path sections.
A lance for a blast furnace tuyere having four flow paths through which a solid or a fluid flows in a parallel state, which constitutes a first flow path of the four flow paths, and has a circular cross section. The formed circular cross-sectional flow path portion and the second flow path of the four flow paths are configured, and the first cross-section of the tubular body is continuously cut in the longitudinal direction to make the cross-section arc-shaped. A first incomplete circular cross-section flow path portion formed by joining both ends of the vertically divided pipe body to the circular cross-section pipe body, and a third flow path among the four flow paths are configured. One end of a second vertically-divided tube having a cross-section cut continuously in the longitudinal direction and having an arc-shaped cross-section is joined to the circular-circular tube, and the second vertically-divided tube A second incomplete circular cross-section channel portion formed by joining the other end of the body to the first vertically-divided tube, and a fourth channel among the four channels Constructed, the cross-section of the tube body is continuously cut in the longitudinal direction, and both ends of the third vertically-divided tube body having an arc-shaped cross section are formed on the first vertically-divided tube body and the second vertically-divided tube body. A third incomplete circular cross section channel formed by joining to the split pipe body, the circular cross section channel and the first, second and third incomplete circular cross section flow The aggregate flow path part is constituted by the path part.
A lance for a blast furnace tuyere having two parallel flow paths through which a solid or a fluid flows, wherein the first flow path of the two flow paths is configured, and a tube having a circular cross section is used. A vertically-divided tubular body that is formed with a circular cross-section flow passage portion and a second flow passage of the two flow passages, and the cross-section of the tubular body is continuously cut in the longitudinal direction so that the cross-section is an arc shape. And an incomplete circular cross-section channel portion formed by joining both end portions of the tube to the tubular body having a circular cross section, and the collective flow channel portion is formed by the circular cross-section channel portion and the incomplete circular cross-section channel portion. It is characterized by comprising.
In addition, using the composite lance for a blast furnace tuyere of the present invention, blowing a solid reducing material and a combustion-supporting gas into the tuyere of the blast furnace, and in some cases blowing a gas reducing material into the tuyere of the blast furnace. The featured blast furnace operating method is suitable for use as a composite lance for blast furnace tuyere of the present invention.

  Thus, according to the composite lance for a blast furnace tuyere of the present invention, there are two or more flow paths through which a solid or fluid flows in a parallel state, and a circular cross-section flow path portion is formed by a tubular section having a circular cross section. A vertical cross-section pipe having a circular cross-section with a circular cross-section flow passage section and a cross-section of the pipe body continuously cut in the longitudinal direction to have an arc-shaped cross section, and other vertical split pipes An incomplete circular cross-section flow path portion is formed by joining to at least one of the body, and any other flow path is constituted by this incomplete circular cross-section flow path portion, and the circular cross-section flow path portion and the incomplete circular cross-section flow path The assembly flow path part was constituted by the part. The circular cross-section flow path section and the incomplete circular cross-section flow path section have a smaller pressure loss with respect to the flow velocity than the gap between the pipes in the heavy tube type lance, and the amount of gas flowing for transporting a gas flowing as a fluid or a solid Even if both the flow velocity and the flow velocity are compatible, the outer diameter of the collective flow path portion does not increase extremely, so the diameter of the entire lance does not increase extremely. Therefore, it becomes possible to blow a desired amount of the solid reducing material, the gas reducing material, and the combustion-supporting gas into the tuyere, and as a result, the reducing material basic unit can be reduced.

In addition, an outer peripheral tube was provided on the outer periphery of the collective flow channel portion, and a gap between the collective flow channel portion and the outer peripheral tube body was used as a cooling fluid flow channel portion for cooling fluid for cooling the collective flow channel portion. Therefore, the diameter of the entire lance is not extremely increased, and the cooling performance of the collective flow path section is excellent and the collective flow path section can be efficiently cooled.
Moreover, the flow path through which the solid flows was constituted by the circular cross-section flow path portion, and the solid reducing material supply means was connected to the flow path constituted by the circular cross-section flow path portion. Since the circular cross-sectional flow path portion has a smaller flow resistance than the incomplete circular cross-sectional flow path portion, the circular cross-sectional flow path portion constitutes a flow path through which solid flows, and a solid reducing material supply means is connected to the flow path. If the solid reducing material is blown, the solid reducing material can be smoothly blown into the tuyere.

It is a longitudinal cross-sectional view which shows one Embodiment of the blast furnace to which the composite lance for blast furnace tuyere of this invention was applied. It is explanatory drawing of a combustion state when only pulverized coal is blown in from the lance of FIG. It is explanatory drawing of the combustion mechanism of the pulverized coal of FIG. It is explanatory drawing of a combustion mechanism when pulverized coal, LNG, and oxygen are blown. It is explanatory drawing of a combustion experiment apparatus. It is explanatory drawing of the blowing pipe | tube in a lance. It is explanatory drawing of the external appearance and arrangement | positioning of a lance. It is explanatory drawing of the combustion rate of a combustion experiment result. It is explanatory drawing of the pressure loss of a combustion experiment result. It is explanatory drawing of the blowing pipe in a lance, and a cooling fluid flow-path part. It is explanatory drawing of the blowing pipe in a lance, and a cooling fluid flow-path part. It is explanatory drawing of the external appearance and arrangement | positioning of a lance. It is explanatory drawing which shows the other example of the blowing pipe | tube in a lance. It is explanatory drawing which shows the further another example of the blowing pipe | tube in a lance. It is explanatory drawing which shows the further another example of the blowing pipe | tube in a lance.

  Next, an embodiment of a composite lance for a blast furnace tuyere of the present invention will be described with reference to the drawings. FIG. 1 is an overall view of a blast furnace to which the present embodiment is applied. As shown in the figure, the tuyere 3 of the blast furnace 1 is connected to a blower pipe (blow pipe) 2 for blowing hot air, and a lance 4 is installed through the blower pipe 2. A combustion space called a raceway 5 exists in the coke deposit layer in the hot air blowing direction ahead of the tuyere 3, and iron ore is reduced, that is, ironmaking is mainly performed in this combustion space. As described above, a lance guide tube (not shown) is inserted into the wall portion of the blower tube 2, and the lance 4 is inserted into the lance guide tube.

FIG. 2 shows a combustion state when only pulverized coal 6 is blown from the lance 4. The pulverized coal 6 that has passed through the tuyere 3 from the lance 4 and is blown into the raceway 5, together with the coke 7, combusts its volatile matter and fixed carbon, and remains unburned, generally called char. The aggregate of ash is discharged as unburned char 8 from the raceway. The hot air velocity at the tip of the tuyere 3 in the direction of blowing hot air is about 200 m / sec, and the region where O ₂ exists in the raceway 5 from the tip of the lance 4 is about 0.3 to 0.5 m. In particular, it is necessary to improve the temperature rise of the pulverized coal particles and the contact efficiency (dispersibility) with O ₂ at a level of 1/1000 second.

  FIG. 3 shows a combustion mechanism when only pulverized coal (PC: Pulverized Coal in the figure) 6 is blown into the blow pipe 2 from the lance 4. The pulverized coal 6 blown into the raceway 5 from the tuyere 3 is heated by the radiant heat transfer from the flame in the raceway 5, and the temperature of the pulverized coal 6 is rapidly increased by the radiant heat transfer and conduction heat transfer. The thermal decomposition starts when the temperature is raised to 300 ° C. or more, and the volatile matter is ignited to form a flame, and the combustion temperature reaches 1400 to 1700 ° C. When the volatile matter is released, the above-described char 8 is obtained. Since the char 8 is mainly fixed carbon, a reaction called a carbon dissolution reaction occurs along with a combustion reaction.

FIG. 4 shows a combustion mechanism when LNG 9 and oxygen (oxygen is not shown) are blown together with pulverized coal 6 from the lance 4 into the blower pipe 2. The blowing method of pulverized coal 6, LNG9, and oxygen shows the case where it blows in parallel simply. In addition, the dashed-two dotted line in a figure has shown the combustion temperature at the time of blowing only the pulverized coal shown in FIG. 3 with reference. When pulverized coal, LNG, and oxygen are blown at the same time, the pulverized coal is dispersed as the gas diffuses, the LNG is burned by the contact of LNG and O ₂ , and the pulverized coal is rapidly heated by the combustion heat. It is thought that the temperature will rise, and this causes the pulverized coal to burn near the lance.

  Based on such knowledge, a combustion experiment was performed using the combustion experiment apparatus shown in FIG. The experimental furnace 11 is filled with coke, and the inside of the raceway 15 can be observed from the viewing window. A lance 4 is inserted into the blower tube 12, and hot air generated in the combustion burner 13 can be blown into the experimental furnace 11 with a predetermined blowing amount. Moreover, in this ventilation pipe 12, it is also possible to adjust the oxygen enrichment amount of ventilation. The lance 4 can blow any one or more of pulverized coal, LNG, and oxygen into the blower pipe 12. The exhaust gas generated in the experimental furnace 11 is separated into exhaust gas and dust by a separator 16 called a cyclone, the exhaust gas is fed to an exhaust gas treatment facility such as an auxiliary combustion furnace, and the dust is collected in a collection box 17.

  In the combustion experiment, a single-tube lance, a triple-tube lance (hereinafter also referred to as a heavy-tube lance), and a parallel-type lance in which three blowing tubes are bundled in parallel are used as the lance 4. Based on the case where only pulverized coal is blown from the single pipe lance, pulverized coal is blown from the inner pipe of the heavy pipe type lance, oxygen is blown from the gap between the inner pipe and the middle pipe, and from the gap between the inner pipe and the outer pipe. When LNG was blown, the combustion rate, pressure loss in the lance, lance surface temperature, and the outer diameter of the lance were measured for each of the cases where pulverized coal, LNG, and oxygen were blown from the blow pipes of the parallel lances. The combustion rate was measured by changing the oxygen blowing flow rate. The burning rate was determined from the amount of unburned charcoal collected from the rear of the raceway with a probe.

  FIG. 6a shows the specifications of each blow pipe of the heavy tube type lance, and FIG. 6b shows the specifications of each blow pipe of the parallel lance. In the heavy tube type lance, a stainless steel pipe having a nominal diameter of 8A and a nominal thickness schedule of 10S is used for the inner pipe I, a stainless steel pipe having a nominal diameter of 15A and a stainless steel pipe having a nominal thickness schedule of 40 is used for the inner pipe, and a nominal diameter of 20A for the outer pipe. A stainless steel pipe having a nominal thickness schedule of 10S was used. The specifications of each stainless steel pipe are as shown in the figure. As a result, the gap between the inner tube I and the middle tube M was 1.15 mm, and the gap between the middle tube M and the outer tube O was 0.65 mm. In the parallel lance, a stainless steel pipe having a nominal diameter of 8A and a nominal thickness schedule of 5S is used as the first pipe 21, a stainless steel pipe having a nominal diameter of 6A and a nominal thickness schedule of 10A is used as the third pipe as the second pipe. Stainless steel tubes having a nominal diameter of 6A and a nominal thickness schedule of 20S were used and bundled. The specifications of each stainless steel pipe are as shown in the figure. The outer diameter of the parallel lance is 25.293 mm, which is slightly smaller than the outer diameter of the outer tube O of the heavy tube lance.

  As will be described in detail later, the actual lance forms a cooling fluid flow path portion outside the blowing pipe shown in FIGS. 6a and 6b, and cools the blowing pipe by flowing a cooling fluid therein. Water is optimal for the cooling fluid, but gases such as nitrogen gas and air can also be used. FIG. 7 shows a parallel lance 4 formed by cooling the water flow by forming a cooling fluid flow outside the parallel blow pipe (the same applies to the heavy pipe lance). Two pipes projecting above the lance are connected to the cooling fluid supply side and the return side, respectively. In the experiment, as shown in FIG. 7 a, pulverized coal (PC) was blown from the first pipe 21 of the parallel lance, LNG was blown from the second pipe 22, and oxygen was blown from the third pipe 23. Note that the insertion length of each lance into the blower pipe (blow pipe) was 200 mm, as shown in FIG. 7b.

  Moreover, when blowing, it can also adjust so that LNG and oxygen may collide with the mainstream of pulverized coal. In the heavy tube lance, pulverized coal, oxygen, and LNG are blown concentrically without colliding with each other. On the other hand, in the parallel type lance, for example, the pulverized coal flow, the oxygen flow, and the LNG flow can be adjusted by adjusting the blowing tip structure. As the tip structure of the blowing tube, for example, a structure in which the tip is cut obliquely or a structure in which the tip is bent can be applied. Among these, when the tip of the blowing tube is cut obliquely, the diffusion state of the blown LNG or oxygen can be changed. Further, when the tip of the blowing tube is curved, the direction of the flow of LNG or oxygen to be blown can be changed.

The specifications of the pulverized coal are 71.3% of fixed carbon (FC), 19.6% of volatile matter (VM), 9.1% of ash (Ash), and the blowing condition is 50.0 kg / h (equivalent to 158 kg / t in the iron making unit). The LNG blowing conditions were 3.6 kg / h (5.0 Nm ³ / h, equivalent to 11 kg / t in the ironmaking base unit). The blowing conditions are as follows: blowing temperature 1100 ° C., flow rate 350 Nm ³ / h, flow rate 80 m / s, O ₂ enrichment +3.7 (oxygen concentration 24.7%, air oxygen concentration 21%, 3.7% wealth) ).

  In FIG. 8, the result of the combustion rate by a combustion experiment is shown. As is clear from the figure, the pulverized coal increases with the increase of the oxygen flow rate in the range where the oxygen flow rate is up to 100 m / s in the heavy tube type lance and the oxygen flow rate is up to 150 m / s in the parallel type lance. The burning rate is increasing. In the case of heavy pipe type lances, the oxygen blown from the lance that diffuses into the hot air (hereinafter referred to as lance-derived oxygen) decreases as the flow rate increases, and the proportion of lance-derived oxygen mixed with pulverized coal increases. In the case of a parallel lance, the lance-derived oxygen that diffuses into the hot air decreases with an increase in the flow rate of oxygen, and the lance-derived oxygen consumed by combustion of volatile matter and LNG decreases, mixing with pulverized coal. This is thought to be due to an increase in the proportion of lance-derived oxygen produced. The reason why the combustion rate data of the heavy tube type lance is limited to the range of the oxygen flow rate of 100 m / s is that the pressure loss becomes the limit. In the parallel lance, the combustion rate decreases in the region where the oxygen flow rate is 150 m / s or more. This is because the flow rate of oxygen from the lance approaches the flow rate of hot air, and the oxygen flow flows in parallel with the pulverized coal flow. This is because the lance-derived oxygen reaches the back of the raceway without mixing with pulverized coal. In FIG. 9, the measurement result of the pressure loss of a heavy tube type lance and a parallel type lance is shown. As is apparent from the figure, the pressure loss at the same flow rate is lower in the parallel lance than in the heavy tube lance. This is because the flow resistance of the heavy pipe type lance is large between the pipes and the flow resistance (ventilation resistance) between the pipes, whereas the flow resistance (ventilation) of the parallel type lance consisting of a circular tube itself is used. This is probably because the resistance is small.

  Thus, the parallel type lance has a smaller pressure loss with respect to the flow velocity than the heavy pipe type lance, and a gas such as LNG or oxygen that flows into the blowing pipe as a fluid or a gas such as nitrogen for conveying pulverized coal. It is possible to satisfy both the gas amount and the flow rate. That is, it is considered that LNG and oxygen necessary for improving the combustion rate of pulverized coal can be blown in a sufficient amount and at a sufficient flow rate, and as a result, it is possible to reduce the reducing material basic unit. However, as a result of intensive studies by the present inventors, it has been found that there is a point to be improved also in the parallel type lance. FIG. 10 is a cross-sectional view of a parallel type lance in which a cooling fluid flow path portion is formed on the outer periphery of the parallel type blowing pipe, that is, the first pipe 21, the second pipe 22, and the third pipe 23. FIG. FIG. 10B is a longitudinal sectional view. When the cooling fluid flow path portion is to be formed on the outer periphery of the first tube 21, the second tube 22, and the third tube 23, for example, the outer tube body 24 is fitted on the outer periphery of these blowing tubes, and further the outer periphery thereof An outermost peripheral tube body 25 is disposed on the outer periphery of the tube body 24. When the outer peripheral tube body 24 and the outermost peripheral tube body 25 are arranged in this way, for example, the gap between the blow tube composed of the first to third tubes 21 to 23 and the outer peripheral tube body 24, the outer peripheral tube body 24, and the outermost peripheral tube body. The cooling fluid channel portion can be formed in each of the gaps between the two.

  Among these, for example, a gap between the blow-in pipe and the outer peripheral tube body 24 is referred to as a supply side cooling fluid flow path portion 18, and a gap between the outer peripheral tube body 24 and the outermost peripheral tube body 25 is referred to as a return side cooling fluid flow path portion 19. Furthermore, as shown in FIG. 10 b, the length of the outer peripheral tube body 24 is made shorter than the length of the outermost peripheral tube body 25, and a gap is formed between the distal end portion of the outermost peripheral tube body 25 and the distal end portion of the outer peripheral tube body 24. The gap between the distal end portion of the outermost peripheral tube body 25 and the blowing tube composed of the first to third tubes 21 to 23 is closed by the lid body 26. Then, a circulation system is formed in which the cooling fluid returns from the supply-side cooling fluid flow path portion 18 covering the outer periphery of the blowing pipe before the lid body 26 and flows into the return-side cooling fluid flow path portion 19. In this way, the bundled blow pipes of the first to third pipes 21 to 23 can be efficiently cooled without extremely increasing the outer diameter of the entire lance, and the cooling efficiency is also extremely good. is there.

  However, the parallel lance in which three (or three or more) blowing tubes are bundled as shown in FIG. 10a has the following problems. That is, the gap formed in the central part of the bundled three (three or more) blowing pipes is a simple gap that does not function or hardly functions as a cooling fluid flow path, is not efficient in space, and is not good for the entire lance. It causes an increase in outer diameter. In addition, the cooling fluid enters the gap formed in the central portion of the blowing pipe unless the gap between the bundled blowing pipes is closed by welding or the like. Since the cooling fluid that has entered leaks from the end of the blowing pipe, for example, the gap in the central part of the blowing pipe must be closed at the lid 26, but it is difficult to close this gap. .

  Therefore, the present inventors have developed a collective flow path portion 31 as shown in FIG. 11, for example, in order to eliminate a gap formed by bundling tubes having a circular cross section. FIG. 11 a is a cross-sectional view perpendicular to the axis of the collecting flow path portion 31, and FIG. 11 b is a vertical cross-sectional view. This collective flow path portion 31 includes a circular cross-section flow path portion 32 that forms a flow path by a single circular tube (circular tube body) 34 itself, and two vertically-divided pipe bodies 35 having a circular arc cross section. And an incomplete circular cross-section channel portion 33 that constitutes two channels. The vertically divided tubular body 35 is, for example, a circular section having a circular cross section that is continuously cut in the longitudinal direction, and the cross section is arcuate. By joining to at least one of the pipe bodies 35, the incomplete circular cross-section flow path portion 33 is formed, and each of the incomplete circular cross-section flow path portions 33 constitutes an independent flow path. In the flow path, LNG or oxygen that is a fluid can be flowed, or pulverized coal that is a solid can be flowed together with a carrier gas such as nitrogen.

  More specifically, as shown in FIG. 11 a, one circular cross-section channel portion 32 is formed by one circular tube 34, and one circular tube 34 is arranged at the lower right of the outer peripheral surface of the circular tube 34. An illustration of the outer circumferential surface of the longitudinally divided tubular body 35 joined at both ends in the circumferential direction of the circular tubular body 34 joined at both ends in the circumferential direction of the longitudinally divided tubular body 35 having an arc shape of about 3/4 in cross section. Two incomplete circular cross-section channel portions 33 are formed by joining both circumferential ends of a longitudinally divided pipe body 35 having an arc shape of about 3/4 in cross section to the left. The collective flow path portion 31 is formed by the portion 32 and the incomplete circular cross-section flow path portion 33. In the present embodiment, the circular tube body 34 constituting the circular cross-section flow path portion 32 and the vertically divided pipe body 35 constituting the incomplete circular cross-section flow passage portion 33 are both made of stainless steel pipes, and the circular pipe body 35 is circular. Welding was used for joining to the pipe body 34 or the other vertically divided pipe body 35. The material of each tubular body and the joining method of the vertically divided tubular bodies may be other than the above.

  Then, similarly to FIG. 10 a, the outer peripheral tube body 24 is fitted on the outer periphery of the collecting channel portion 31, and the outermost peripheral tube body 25 is disposed on the outer periphery of the outer peripheral tube body 24. When the outer peripheral tube body 24 and the outermost peripheral tube body 25 are arranged in this way, the cooling fluid is respectively provided in the gap between the collecting flow path portion 31 and the outer peripheral tube body 24 and in the gap between the outer peripheral tube body 24 and the outermost outer tube body 25. A flow path part can be formed. Therefore, a gap between the blow-in pipe and the outer peripheral tube body 24 is referred to as a supply-side cooling fluid channel portion 18, and a gap between the outer peripheral tube body 24 and the outermost peripheral tube body 25 is referred to as a return-side cooling fluid channel portion 19. Further, as shown in FIG. 11 b, the length of the outer peripheral tube body 24 is made shorter than the length of the outermost peripheral tube body 25 so that a gap is formed between the distal end portion of the outermost peripheral tube body 25 and the distal end portion of the outer peripheral tube body 24. The gap between the distal end portion of the outermost peripheral tube body 25 and the collecting flow path portion 31 is closed by the lid body 26.

  FIG. 12a shows the appearance of the lance 4 configured as described above (hereinafter also referred to as a joining lance), and FIG. The insertion length of the junction type lance 4 into the blower tube was 200 mm. Also in this junction type lance 3, the cooling fluid returns from the supply side cooling fluid channel portion 18 covering the outer periphery of the collecting channel portion 31 in front of the lid body 26 and flows into the return side cooling fluid channel portion 19. And if it does in this way, without increasing the outer diameter of the whole lance extremely, the gathering channel part 31 can be cooled efficiently and the cooling efficiency is also very favorable. At this time, there is no gap continuous in the axial direction between the tubes of the collecting flow path portion 31, so that the cooling fluid does not enter the gap. Further, in the junction type lance 4 of the present embodiment, pulverized coal is blown together with the carrier gas from the circular cross-section flow path portion 32 formed of the circular tubular body 34, and each of the incomplete circular cross-section flow path portions 33 formed of the vertically divided pipe bodies 35. LNG and oxygen were blown from. That is, the pulverized coal supply means is connected to the circular cross-sectional flow path section 32, and the LNG supply means and the oxygen supply means are connected to the incomplete circular cross-section flow path section 33, respectively. The incomplete circular cross-section channel portion 33 also has a smaller flow resistance than the pipe-to-tube gap in the heavy tube lance, but the circular cross-section channel portion 32 has a smaller flow resistance. Therefore, the pulverized coal can be smoothly blown into the tuyere by blowing the pulverized coal from the circular cross-sectional flow path portion 32. The supply side and the return side of the cooling fluid flow path may be reversed.

In FIG. 11, the circular cross-section flow path portion 32 is formed of a tube having an inner diameter (diameter) of 17.5 mm and a tube thickness of 2.1 mm, and the two incomplete circular cross-section flow path portions 33 have an inner diameter (diameter) of 23 mm and a tube thickness of 2 When formed with a 1 mm vertical split pipe, the cross-sectional area of the circular cross-section flow path portion 32 is 240 mm ² , the incomplete circular cross-section flow path section 33 is 320.18 mm ² , and the inner diameter of the outer tube 24 is 42 mm. there were. Further, when the three pipes (including the split pipe) are arranged so as to be in contact with the outer peripheral pipe, the line segment connecting the center of each pipe and the center of the outer peripheral pipe is 120 ° on the cross-sectional view 11. Arranged to form an angle. If the same cross-sectional area is realized in the parallel type of FIG. 10 composed of the first tube 21, the second tube 22, and the third tube 23 using tubes having the same tube thickness, the inner diameter of each tube is about 17. The inner diameter of the outer diameter tube is required to be 5 mm, 20 mm, and 15 mm. Needless to say, the dimensions and arrangement of each flow path are not limited to the above, but the solid reducing material flow path is a circular tube having an inner diameter of about 10 to 20 mm, a combustion-supporting gas flow path, or a gas reducing material flow path. The path is preferably formed by a longitudinally divided tube having an inner diameter of about 15 to 25 mm.

  13 to 15 show various modifications of the blast furnace tuyeres composite lance (joint lance) 4 of the present embodiment. These figures are all cross-sectional views perpendicular to the axis of the lance. Further, the outer peripheral tube body 24 is arranged on the outer periphery of the collective flow path portion 31 of all the modified examples, and the gap between them is used as the supply side cooling fluid flow path portion 18, and the outermost peripheral tube body 25 is disposed on the outer periphery of the outer peripheral tube body 24. The gap between the two is used as a return side cooling fluid channel portion 19. In FIG. 13 a, two circular tube bodies 34 are arranged in parallel and joined together to form two parallel circular cross-section flow channel portions 32, and one parallel outer peripheral surface of these circular tube bodies 34 is connected. As described above, one incomplete circular cross-section flow path portion 33 is formed by joining the circumferential end portion of the vertically divided pipe body 35 having a semicircular cross section in cross section to the outer peripheral surface of each circular pipe body 34, The collective flow channel portion 31 is formed by the circular cross-sectional flow channel portion and the incomplete circular cross-sectional flow channel portion 33. Further, in FIG. 13 b, as in FIG. 13 a, two parallel circular cross-sectional flow channel portions 32 are formed by arranging two circular tubes 34 in parallel and joining each other. Two incomplete circles are formed by joining the circumferential ends of the two longitudinally split pipes 35 having a semicircular arc shape in cross section to the outer peripheral faces of the circular pipes 34 so as to connect two parallel outer peripheral faces, respectively. The cross-sectional flow path part 33 is formed, and the collective flow path part 31 is formed by the circular cross-sectional flow path part and the incomplete circular cross-sectional flow path part 33.

  FIG. 14 shows a case where four flow paths for flowing pulverized coal as a solid, LNG as a fluid, and oxygen are formed. This junction type lance 4 forms one circular cross-section flow path portion 32 by one circular tube 34, and has a cross section of about 3/4 circle at the lower left of the outer peripheral surface of the circular tube 34 in the figure. The arcuate vertically divided pipes 35 are joined at both ends in the circumferential direction, and the right side of the outer peripheral face of the circular pipe 34 and the right side of the outer peripheral face of the vertically split pipe 35 joined first are shown. The ends of the circumferentially divided tubular bodies 35 having a circular arc shape of about 3/4 are joined to each other in the circumferential direction. Three incomplete circular cross-section flow path portions 33 are formed by joining the respective circumferential ends of the split pipe body 35, and are assembled by the circular cross-section flow path portion 32 and the incomplete circular cross-section flow path portion 33. A flow path portion 31 is formed.

  FIG. 15 shows a case where two flow paths for flowing solid pulverized coal, fluid LNG and oxygen are formed. This junction type lance 4 forms one circular cross-section flow path portion 32 by one circular tube 34, and has a cross section of about 2/3 arc in the lower part of the outer peripheral surface of the circular tube 34. One incomplete circular cross-section flow path portion 33 is formed by joining both ends in the circumferential direction of the vertically divided pipe body 35, and the circular cross-section flow path portion 32 and the incomplete circular cross-section flow path portion 33 are assembled together. A flow path portion 31 is formed.

  As described above, the composite lance for a blast furnace tuyere of this embodiment has two or more flow paths through which a solid or fluid flows in a parallel state, and the circular cross-section channel portion 32 is formed by the circular tubular body 34. One of the flow paths is constituted by the flow path section 32, and the longitudinally divided tubular body 35 in which the cross section of the tubular body is continuously cut out in the longitudinal direction and the cross section is formed in an arc shape is formed into the circular tubular body 34 and the other vertically divided tubular bodies. 35, an incomplete circular cross-section channel portion 33 is formed by joining to at least one of them, and any other channel is constituted by this incomplete circular cross-section channel portion 33. The collective flow path portion 31 is configured by the cross-sectional flow path portion 33. The circular cross-section flow path section 32 and the incomplete circular cross-section flow path section 33 have a smaller pressure loss with respect to the flow velocity than the gap between the pipes in the heavy tube type lance, and the gas flow for transporting a gas or solid flowing as a fluid. Even if both the gas amount and the flow rate are compatible, the outer diameter of the collective flow path portion 31 does not increase excessively, so the diameter of the entire lance does not increase extremely. Therefore, it becomes possible to blow a desired amount of the solid reducing material, the gas reducing material, and the combustion-supporting gas into the tuyere, and as a result, the reducing material basic unit can be reduced.

Further, the outer peripheral tube body 24 is provided on the outer periphery of the collecting channel portion 31, and the cooling fluid channel for cooling fluid for cooling the collecting channel portion 31 through the gap between the collecting channel portion 31 and the outer tube body 24. Part 18 was designated. For this reason, the collective flow path portion 31 can be efficiently cooled without excessively increasing the diameter of the entire lance and with excellent cooling performance of the collective flow path portion 31.
In addition, a flow path through which the pulverized coal flows is formed by the circular cross-sectional flow path portion 32, and a pulverized coal supply unit is connected to the flow path formed by the circular cross-sectional flow path portion 32. Since the circular cross-section flow path portion 32 has a smaller flow resistance than the incomplete circular cross-section flow path portion 33, the circular cross-section flow path portion 32 constitutes a flow path through which pulverized coal flows, and pulverized coal supply means is provided in the flow path. By connecting and blowing pulverized coal, the pulverized coal can be smoothly blown into the tuyere.

DESCRIPTION OF SYMBOLS 1 Blast furnace 2 Blower pipe 3 Tuyere 4 Lance 5 Raceway 6 Pulverized coal (solid reducing material)
7 Coke 8 Char 9 LNG (Gas reducing material)
18 Supply-side cooling fluid flow path section 19 Return-side cooling fluid flow path section 24 Outer peripheral tube body 25 Outermost peripheral tube body 26 Lid body 31 Collective flow path section 32 Circular cross-section flow path section 33 Incomplete circular cross-section flow path section

Claims (10)

A lance for a blast furnace tuyere having three flow paths through which a solid or fluid flows,
A first cross-section of the three flow paths is configured, and a circular cross-sectional flow channel portion formed by a tube having a circular cross-section,
Of the three flow paths, the second flow path is configured, and the cross section of the first vertically divided pipe body in which the cross section of the pipe body is continuously cut out in the longitudinal direction so that the cross section has an arc shape. and an incomplete circular cross-sectional flow portion of the first one formed by engagement against the circular tube,
Of the three flow paths, a third flow path is configured, and one end portion of a second vertically-divided pipe body in which the cross section of the pipe body is continuously cut out in the longitudinal direction and the cross section is formed in an arc shape. A second incomplete circular cross-section channel part formed by joining the circular pipe body and joining the other end of the second vertical pipe body to the first vertical pipe body; With
A combined lance for a blast furnace tuyere comprising a collective flow path portion by the circular cross-sectional flow path portion and the first and second incomplete circular cross-sectional flow path portions.   The lance for a blast furnace tuyere according to claim 1, further comprising a cooling fluid channel portion for cooling fluid for cooling the collective channel portion.   3. The blast furnace tuyere according to claim 2, wherein an outer peripheral tube is provided on an outer periphery of the collective flow passage portion, and a gap between the collective flow passage portion and the outer peripheral tube portion is used as the cooling fluid flow passage portion. For composite lance. Any one of the three flow paths is a flow path through which the solid flows, and among the three flow paths, two flow paths excluding the flow path through which the solid flows are flow paths through which the fluid flows,
Solid reducing agent supply means for supplying a solid reducing material is connected to the channel through the pre-Symbol solids,
Blast furnace according to any one of claims 1 to 3, characterized in that the combustion assisting gas supply means for supplying a combustion-supporting gas is connected to any one of the previous SL flow path through which fluid flows Combined lance for tuyere. Gas reducing material supply means for supplying a gas material reducing material, characterized in that the combustion supporting gas supply means is connected to any one other than the flow path of the flow path through which the fluid being connected The lance for a blast furnace tuyere according to claim 4 . The first flow path of the three flow paths constituting the circular cross-section flow path portion constitutes a flow path through which the solid flows,
The lance for a blast furnace tuyere according to claim 4 or 5 , wherein the solid reducing material supply means is connected to a flow path in which the solid flows, which is constituted by the circular cross section flow path section. A lance for a blast furnace tuyere having three flow paths through which a solid or fluid flows,
The first channel of the three channels, the first circular cross-section channel part formed by the first tube body having a circular cross-section,
A second circular cross-sectional flow path that forms a second flow path of the three flow paths and is joined to the first tubular body and formed by a second tubular body having a circular cross section. When,
Of the three channels, a third channel is formed, and both ends of a vertically divided tube whose cross section is continuously cut in the longitudinal direction to have an arc-shaped cross section are formed on the first tube. A body and an incomplete circular cross-section channel formed by joining to the second tube,
A combined lance for a blast furnace tuyere, wherein the first and second circular cross-sectional flow path portions and the incomplete circular cross-sectional flow path portion constitute a collective flow path portion. A compound lance for a blast furnace tuyere having four flow paths through which a solid or fluid flows,
The first channel of the four channels, the first circular cross-section channel portion formed by the first tube having a circular cross-section,
A second circular cross-section flow path that forms a second flow path among the four flow paths and is formed by a second pipe body that is joined to the first pipe body and has a circular cross section. And
Of the four channels, a third channel is configured, and both ends of the first vertically divided tube whose cross section is continuously cut in the longitudinal direction to have an arc-shaped cross section are formed on the one end. A first tubular body and a first incomplete circular cross-section channel formed by joining to the second tubular body;
  Among the four channels, a fourth channel is configured, and both ends of a second vertically-divided tube body in which the section of the tube body is continuously cut out in the longitudinal direction so that the section is arcuate. A second tube and a second incomplete circular cross-section channel formed by joining to the second tube,
  A combined blast furnace tuyere comprising the first and second circular cross-sectional flow passages and the first and second incomplete circular cross-sectional flow passages. Lance. A compound lance for a blast furnace tuyere having four flow paths through which a solid or fluid flows,
  A first cross-section of the four flow paths, and a circular cross-section channel portion formed by a tubular body having a circular cross-section;
  Of the four flow paths, the second flow path is configured, and the cross section of the first vertically divided pipe body in which the cross section of the pipe body is continuously cut out in the longitudinal direction so that the cross section has an arc shape. A first incomplete circular cross-section flow channel portion formed by joining a circular tube;
  Of the four channels, a third channel is configured, and one end portion of a second vertically-divided tube body in which the cross section of the tube body is continuously cut out in the longitudinal direction and the cross section is formed in an arc shape. A second incomplete circular cross-section channel part formed by joining the circular pipe body and joining the other end of the second vertical pipe body to the first vertical pipe body; ,
  Among the four channels, a fourth channel is configured, and both ends of a third vertically-divided tube body in which a cross section of the tube body is continuously cut in the longitudinal direction so that the cross section has an arc shape are formed on the one end. A third vertically-divided tubular body and a third incomplete circular cross-section channel portion formed by joining to the second vertically-divided tubular body,
  A combined lance for a blast furnace tuyere comprising a collective flow path portion by the circular cross-sectional flow path portion and the first, second, and third incomplete circular cross-sectional flow path portions. A composite lance for a blast furnace tuyere having two parallel flow paths through which a solid or fluid flows,
A first cross-section of the two flow paths, a circular cross-section flow channel portion formed by a tube having a circular cross-section;
  A tubular body having a circular cross section is formed at both ends of a vertically divided tubular body that forms a second flow path of the two flow paths, and the cross section of the tubular body is continuously cut out in the longitudinal direction so that the cross section has an arc shape. An incomplete circular cross-section flow path portion formed by joining to,
  A combined lance for a blast furnace tuyere characterized in that a collective flow path portion is constituted by the circular cross-sectional flow path portion and the incomplete circular cross-sectional flow path portion.

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