Gas sampling method and gas sampling device

Abstract

To provide a gas sampling method and a gas sampling device capable of sampling gas generated in a container by suppressing contact between the gas generated in the container and an operator while reducing cost.SOLUTION: A gas sampling method according to the present invention is a gas sampling method for sampling in-vessel generated gas generated in a reaction vessel by inserting a lance into the reaction vessel through a connection pipe whose inside is connected to the reaction vessel, the gas sampling method including a step of connecting a tubular member to communicate with the connection pipe, and a step of inserting a tip portion of a lance from an opening portion having a seal member of the tubular member in a state where inert gas is introduced into an internal space of the tubular member from a gas introduction pipe connected to an outer circumferential surface of the tubular member and the inert gas is continuously introduced into the internal space.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a gas sampling method and a gas sampling device. [Background technology]

[0002] In blast furnace operation, coke is burned using air and oxygen blown into the furnace from the bottom, generating high-temperature CO gas, which is then used to reduce iron ore to produce pig iron. The efficiency of the reduction reaction varies depending on various operating conditions but is never 100%. Therefore, any high-temperature CO gas that is not consumed by the reduction reaction in the furnace is constantly vented from the top of the furnace and used as a valuable gas. Increasing the amount of CO gas generated, i.e., increasing the amount of air and oxygen blown into the furnace from the bottom, is effective in increasing pig iron productivity. However, due to the risk of flooding of the materials in the furnace due to increased gas velocity, high-pressure operation is required, which suppresses the increase in gas velocity by increasing the furnace top pressure.

[0003] In blast furnace operation, the required production volume must be achieved stably and at low cost, and it is important that the gas flow and gas composition within the furnace are stable. However, since the properties of the charged materials are not always constant, the gas flow and gas composition within the furnace are prone to fluctuations. Therefore, it is important to monitor the fluctuations in the gas flow and gas composition within the furnace and take operational action to keep them within a certain range, and furnace gas is sampled and analyzed.

[0004] Sampling furnace gas involves certain risks. Therefore, appropriate equipment measures are taken to ensure safety when sampling furnace gas. Patent Document 1 discloses a method for protecting workers from the escape of furnace gas by providing a sealed box and valve for sealing inert gas at the gas sampling position of the furnace body. Patent Document 2 discloses a method for protecting workers from the escape of furnace gas by using an expandable body that expands when gas is sealed in it and blocking the flow of gas. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 149806 / 1983 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-117039 Summary of the Invention [Problem to be solved by the invention]

[0006] The method disclosed in Patent Document 1 requires the installation of a sealed box and valves for sealing inert gas at each gas sampling location. However, when attempting to modify an operating blast furnace, workers are exposed to the furnace gas, necessitating the shutdown of the blast furnace to perform the modification. Furthermore, the modification requires the furnace body to be opened, which may significantly hinder workability, such as causing the charge materials inside the furnace to leak. Therefore, the timing for modifying a blast furnace is limited to blow-in or banking. Considering the impact on pig iron production and the cost, modification is practically difficult. Furthermore, the need to install a sealed box and valves for sealing inert gas at each gas sampling location in the furnace body poses a challenge from an economic standpoint. Furthermore, the furnace body is subject to high temperatures due to heat generated by reactions within the furnace, reaching approximately 250°C, depending on the location and equipment deterioration. Therefore, if a sealed box and valve for sealing inert gas are installed on the furnace body side, they will become hot due to the heat from the furnace body, causing deformation and shortening their lifespan. In order to prevent this, it becomes necessary to constantly cool the seal box and the valve using a dedicated cooling device during blast furnace operation, which leads to high costs. The method disclosed in Patent Document 2 has the same problems as the method disclosed in Patent Document 1, and also imposes a maintenance burden of maintaining the soundness of the expansion body itself.

[0007] The present invention has been made in consideration of the above-mentioned problems, and its object is to provide a gas sampling method and gas sampling device that can sample gas generated in a container while reducing costs and preventing contact between the gas generated in the container and an operator. [Means for solving the problem]

[0008] In order to solve the above problems and achieve the objectives, (1) A gas sampling method according to the present invention is a gas sampling method for inserting a lance into a reaction vessel through a connecting pipe whose interior is connected to the reaction vessel and sampling gas generated in the reaction vessel, the method comprising the steps of: connecting a tubular member in communication with the connecting pipe; introducing an inert gas into the internal space of the tubular member from a gas introduction pipe connected to the outer peripheral surface of the tubular member; and inserting the tip of the lance through an opening having a sealing member of the tubular member while continuing to introduce the inert gas into the internal space.

[0009] (2) In the gas sampling method according to the present invention, in the invention (1) above, the pressure of the inert gas introduced into the internal space from the gas inlet pipe is equal to or greater than the pressure inside the reaction vessel at the position where the gas generated inside the vessel is sampled.

[0010] (3) The gas collection method according to the present invention, in the invention (1) or (2) above, includes a step of using a gas suction device to suck and collect the gas generated in the container through an intake port provided at the tip of the lance.

[0011] (4) In the gas collection method according to the present invention, in any one of the above (1) to (3), the inside of the reaction vessel is at high temperature and high pressure.

[0012] (5) The gas sampling device according to the present invention is a gas sampling device that inserts a lance into a reaction vessel through a connecting pipe whose interior is connected to the reaction vessel and samples gas generated in the vessel, and includes a tubular member that is detachably connected in communication with the connecting pipe and into which the tip of the lance is inserted through an opening having a sealing member, and a gas introduction pipe that is connected to the outer peripheral surface of the tubular member and that introduces an inert gas into the internal space of the tubular member.

[0013] (6) In the gas sampling device of the present invention, in the invention (5) above, the pressure of the inert gas introduced into the internal space from the gas inlet pipe is equal to or greater than the pressure inside the reaction vessel at the position where the gas generated inside the vessel is sampled.

[0014] (7) The gas sampling device according to the present invention, in the invention of (5) or (6) above, further comprises a gas suction machine that sucks the gas generated in the container through an intake port provided at the tip of the lance.

[0015] (8) The gas collection device according to the present invention is any one of the above (5) to (7), wherein the inside of the reaction vessel is at high temperature and high pressure. [Effects of the Invention]

[0016] The gas sampling method and gas sampling device according to the present invention have the advantage of being able to sample the gas generated in the container while preventing contact between the gas generated in the container and an operator. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a diagram showing a state in which a gas collection device according to an embodiment is attached to a blast furnace. [Figure 2] FIG. 2 shows the state before the gas sampling device is attached to the connecting pipe of the blast furnace. [Figure 3] FIG. 3 is a diagram showing a state in which the tubular member of the gas shielding device is connected to the connecting pipe of the blast furnace. [Figure 4]FIG. 4 is a diagram showing a state in which a gas sampling device is attached to the connecting pipe of a blast furnace. [Figure 5] FIG. 5 is a diagram showing a gas collection method of a comparative example. [Figure 6] FIG. 6 is a graph showing the relationship between the CO gas concentration measured outside the furnace and the measurement time when the gas inside the furnace was sampled using the gas sampling method of the present invention and the gas sampling method of the comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, embodiments of the gas sampling method and gas sampling device according to the present invention will be described. However, the present invention is not limited to these embodiments. That is, the gas sampling method and gas sampling device according to the present invention can be applied in many fields as a method and device capable of sampling gas in a container, for example, sampling CO gas generated during blowing in a converter and monitoring the blowing progress (operation progress).

[0019] 1 is a diagram showing a state in which a gas sampling device 1 according to an embodiment is attached to a blast furnace 2. The gas sampling device 1 according to an embodiment includes a gas shielding device 10, a sampling lance 11, a gas container 15, an on-off valve 16, and the like.

[0020] The gas shielding device 10 includes a tubular member 12, an inert gas introduction pipe 13, and an inert gas discharge pipe 14. Flanges 120 and 121 are provided at one and the other axial ends of the tubular member 12, respectively. The flange 120 of the tubular member 12 is fastened and connected to a flange 221 provided at one end of a connection pipe 22 of the blast furnace 2 with fastening members such as bolts. The tip of the sampling lance 11 is inserted into the furnace body 21 of the blast furnace 2 through an opening provided on the end face of the tubular member 12 on the flange 121 side, via the tubular member 12 and the connection pipe 22. The rear end of the sampling lance 11 is connected to a gas container 15. The gas container 15 contains the furnace gas in the furnace body 21 that has passed through the sampling lance 11 from an intake port provided on the tip face of the sampling lance 11.

[0021] The on-off valve 16 is provided on the rear end side of the sampling lance 11 so as to be able to selectively switch between opening and closing the gas flow path formed by the internal space of the sampling lance 11 .

[0022] The inert gas inlet pipe 13 and the inert gas outlet pipe 14 are connected to the outer circumferential surface of the tubular member 12 and communicate with the internal space of the tubular member 12. The inert gas inlet pipe 13 is a pipe for introducing an inert gas supplied from an inert gas supply device (not shown) into the hollow interior of the tubular member 12. The inert gas may be, for example, nitrogen gas. The inert gas outlet pipe 14 is a pipe for recovering the inert gas from the hollow interior of the tubular member 12 using an inert gas recovery device (not shown).

[0023] In the gas shielding device 10, an inert gas is introduced into the internal space of the tubular member 12 from an inert gas supply device through an inert gas introduction pipe 13, so that the internal space of the tubular member 12 is filled with the inert gas.

[0024] The opening provided on the end face of the flange 121 side of the tubular member 12 is provided with a seal packing, which is a sealing member that seals the gap between the outer peripheral surface of the sampling lance 11 and the inner peripheral surface of the opening when the tip of the sampling lance 11 is inserted. This makes it possible to prevent the inert gas introduced into the internal space of the tubular member 12 from leaking between the outer peripheral surface of the sampling lance 11 and the inner peripheral surface of the opening when the sampling lance 11 is inserted through the opening of the tubular member 12.

[0025] The blast furnace 2 has a furnace body 21, which is a high-temperature, high-pressure reaction vessel, and a connecting pipe 22 is connected to the outer wall of the furnace body 21 via a flange 220. Raw materials such as sintered ore, iron ore, coke, limestone, and pellets are charged into the furnace body 21 from the top. The temperature inside the furnace body 21 varies greatly from the bottom to the top (upper part) of the furnace body 21. At the bottom of the furnace body 21, the temperature is approximately 2300°C at the tip of the opening (tuyere), and is normally approximately 150°C at the top of the furnace body 21. However, the temperature inside the furnace body 21 also fluctuates depending on the operating conditions, and even at the top of the furnace body 21, a high temperature of approximately 300°C can occur under normal circumstances.

[0026] A flange 221 connectable to the flange 120 of the tubular member 12 is provided on the opposite side of the flange 220 in the longitudinal direction of the connection pipe 22. A first opening / closing valve 23 and a second opening / closing valve 24 are provided in a longitudinally intermediate portion of the connection pipe 22. The first opening / closing valve 23 and the second opening / closing valve 24 selectively open and close the internal space of the connection pipe 22. The first opening / closing valve 23 is provided on the flange 221 side of the connection pipe 22. The second opening / closing valve 24 is provided on the flange 220 side of the connection pipe 22. An exhaust pipe 25 is connected between the first opening / closing valve 23 and the second opening / closing valve 24 in the longitudinal direction of the connection pipe 22 so as to communicate with the internal space of the connection pipe 22. A third opening / closing valve 26 is provided in a longitudinally intermediate portion of the exhaust pipe 25, selectively open and close the internal space of the exhaust pipe 25.

[0027] The gas sampling method according to the embodiment includes a step of connecting a tubular member 12 to an end of the connecting pipe 22 on the opposite side of the furnace body 21 in the longitudinal direction while closing the first on-off valve 23 and the second on-off valve 24 of the connecting pipe 22, in communication with the connecting pipe 22. The gas sampling method according to the embodiment also includes a step of introducing an inert gas into the internal space of the tubular member 12 from an inert gas introduction pipe 13 connected to the outer peripheral surface of the tubular member 12. The gas sampling method according to the embodiment also includes a step of inserting a sampling lance 11 through an opening having a seal packing provided on the end face of the tubular member 12 on the opposite side of the connecting pipe 22 in the longitudinal direction while continuing to introduce the inert gas into the internal space of the tubular member 12. The gas sampling method according to the embodiment also includes a step of opening the first on-off valve 23 and the second on-off valve 24, and inserting the tip of the sampling lance 11 into the furnace body 21 through the tubular member 12 and the connecting pipe 22. The gas sampling method according to the embodiment also includes a step of collecting the furnace gas in the gas container 15 through the sampling lance 11 from an intake port provided at the tip of the sampling lance 11 and through the sampling lance 11 .

[0028] In the gas sampling method according to the embodiment, the furnace gas may be sucked by a gas aspirator (not shown) and collected by passing the in-furnace gas through an intake port provided at the tip of the sampling lance 11 into the gas container 15. This allows the suction force of the gas aspirator to be controlled, and the flow rate of the in-furnace gas flowing through the sampling lance 11 to be adjusted to a constant rate, thereby allowing the in-furnace gas to be sampled.

[0029] Next, a detailed description will be given of the procedure for sampling furnace gas from within the furnace body 21 by the gas sampling method according to the embodiment. Fig. 2 is a diagram showing the state before the gas sampling device 1 is attached to the connection piping 22 of the blast furnace 2. Fig. 3 is a diagram showing the state after the tubular member 12 of the gas shielding device 10 is connected to the connection piping 22 of the blast furnace 2. Fig. 4 is a diagram showing the state after the gas sampling device 1 is attached to the connection piping 22 of the blast furnace 2.

[0030] When furnace gas is not being sampled during normal blast furnace operation, as shown in FIG. 2, the gas sampling device 1 is not attached to the connecting piping 22 of the blast furnace 2, and the first on-off valve 23, the second on-off valve 24, and the third on-off valve 26 are closed. When attaching the gas sampling device 1 to the connecting piping 22 of the blast furnace 2, as shown in FIG. 3, the flange 120 attached to the tubular member 12 of the gas shielding device 10 and the flange 221 attached to the connecting piping 22 of the blast furnace 2 are fastened together with bolts and nuts. Next, with the first on-off valve 23, the second on-off valve 24, and the third on-off valve 26 closed, the tip of the sampling lance 11 is inserted through the opening of the tubular member 12. At this point, the tip of the sampling lance 11 can be inserted up to the position of the first on-off valve 23. The on-off valve 16 attached to the sampling lance 11 is closed.

[0031] Next, the operator connects the inert gas inlet pipe 13 and the inert gas outlet pipe 14 in the gas shielding device 10, and introduces inert gas from the inert gas supply device through the inert gas inlet pipe 13 into the space inside the tubular member 12, as shown in FIG. 4 . While the interior space of the tubular member 12 is filled with inert gas in this manner, the operator switches the first on-off valve 23 of the connecting pipe 22 to an open state. Next, the operator inserts the tip of the sampling lance 11 to the position of the second on-off valve 24 of the connecting pipe 22 and switches the second on-off valve 24 to an open state. Then, the operator inserts the tip of the sampling lance 11 into the furnace body 21 and switches the on-off valve 16 of the sampling lance 11 to an open state. As a result, the furnace gas passes through the sampling lance 11 from the intake port provided on the tip surface of the sampling lance 11, is stored in the gas container 15, and is collected from the furnace body 21.

[0032] In addition, in the gas shielding device 10, a seal packing and an inert gas are used to suppress gas from leaking from between the outer circumferential surface of the sampling lance 11 and the inner circumferential surface of the opening. The furnace pressure in the furnace body 21 varies significantly depending on the location where the furnace gas is collected. For example, the pressure is approximately atmospheric pressure + 450 kPa at the bottom of the furnace body 21 and approximately atmospheric pressure + 250 kPa at the top of the furnace body 21. The pressure of the inert gas introduced into the internal space of the tubular member 12 of the gas shielding device 10 is preferably equal to or higher than the furnace pressure at the location where the furnace gas is collected by the gas collection device 1 in order to suppress gas from leaking. While some furnace gas is expected to leak into the tubular member 12, the inert gas is diluted with the inert gas and discharged from the tubular member 12 together with the inert gas through the inert gas discharge pipe 14. Furthermore, the inert gas not only suppresses the emission of furnace gas from the tubular member 12, but also has the effect of suppressing, albeit for a short time, the rise in temperature of the tubular member 12, which is the connecting portion of the gas shielding device 10 at the connection with the connecting pipe 22 of the furnace body 21. As a result, the gas sampling method according to the embodiment can suppress the tubular member 12 connected to the connecting pipe 22 of the furnace body 21 from becoming too hot due to the heat from the furnace body 21 during blast furnace operation, which can cause deformation and shorten the lifespan of the tubular member 12.

[0033] Next, after the sampling of the furnace gas by the gas sampling device 1 is completed, the operator closes the second on-off valve 24 and the first on-off valve 23 while withdrawing the tip of the sampling lance 11 from the furnace body 21. At this time, the introduction of the inert gas into the tubular member 12 of the gas shielding device 10 continues until the first on-off valve 23 is closed. Furthermore, once the first on-off valve 23 is closed, the introduction of the inert gas into the tubular member 12 may be stopped before the tip of the sampling lance 11 is withdrawn from the tubular member 12 of the gas shielding device 10.

[0034] In the method for sampling in-furnace gas of a blast furnace 2 using the gas sampling device 1 according to the embodiment, it is sufficient that at least one connection pipe 22 to which the tubular member 12 of the gas shielding device 10 is connected is provided on the furnace body 21 side of the blast furnace 2. In the gas sampling device 1 according to the embodiment, the tubular member 12 of the gas shielding device 10 is attached to the connection pipe 22 of the blast furnace 2 only when sampling in-furnace gas. Therefore, since the gas shielding device 10 is not permanently installed on the blast furnace 2 side, a dedicated cooling device for cooling the tubular member 12 of the gas shielding device 10 is not required. As a result, the gas sampling device 1 according to the embodiment does not require a dedicated cooling device for cooling the tubular member 12 of the gas shielding device 10, thereby reducing costs. In addition, because the gas sampling device 1 is portable, it is possible to share one gas sampling device 1 at multiple gas sampling locations in the blast furnace 2 without having to modify the equipment on the furnace body 21 side.

[0035] As described above, in the method for collecting furnace gas from a blast furnace 2 using the gas collection device 1 according to the embodiment, it is possible to reduce costs while suppressing contact between the furnace gas and workers and collecting the furnace gas. [Example]

[0036] Next, the gas sampling method and gas sampling device according to the embodiment will be described based on examples, but the present embodiment is not limited to the following examples.

[0037] In this example, a comparison was made between the CO gas concentration measured outside the furnace when sampling gas inside the blast furnace 2 using the gas sampling method of the invention using the gas sampling device 1 according to the embodiment shown in FIG. 1 and the gas sampling method of the comparative example shown in FIG. 5.

[0038] 5, in the gas sampling method of the comparative example, a gas shielding device 10 is not attached to the connecting pipe 22 of the blast furnace 2, and a sampling lance 11 is directly inserted through an opening provided in the end face of the connecting pipe 22 on the flange 221 side to sample the in-furnace gas. In this case, no sealing member such as a seal packing is provided to close the gap between the outer peripheral surface of the sampling lance 11 and the inner peripheral surface of the opening provided in the end face of the connecting pipe 22 on the flange 221 side. Therefore, in the gas sampling method of the comparative example, a first opening / closing valve 23 and a second opening / closing valve 24 provided on the connecting pipe 22 of the blast furnace 2 are opened to eject the in-furnace gas through the connecting pipe 22 into the outside air.

[0039] FIG. 6 is a graph showing the relationship between the CO gas concentration measured outside the furnace and the measurement time when the gas inside the furnace was sampled using the gas sampling method of the present invention and the gas sampling method of the comparative example.

[0040] In the gas sampling method of the present invention, as shown in Fig. 6, the CO gas concentration measured outside the furnace while sampling the furnace gas remains at approximately 0, indicating that gas ejection outside the furnace is suppressed by the gas shielding device 10. On the other hand, in the gas sampling method of the comparative example, the furnace gas is ejected into the outside air through the connecting pipe 22 while sampling the furnace gas, and as shown in Fig. 6, the CO gas concentration measured outside the furnace exceeds the monitor's upper measurement limit of 2000 ppm.

[0041] As described above, the gas sampling method of the present invention can sample the furnace gas while preventing contact between the furnace gas and the worker. [Explanation of symbols]

[0042] 1 Gas sampling device 2 blast furnace 10 Gas shielding device 11 Sampling Lance 12 Tubular member 13 Inert gas introduction piping 14 Inert gas exhaust piping 15 Gas container 16 Opening and closing valve 21 Furnace body 22 Connecting piping 23 First opening and closing valve 24 Second opening and closing valve 25 exhaust pipe 26 Third opening and closing valve

Claims

1. A gas sampling method for sampling a gas generated in a reactor vessel by inserting a lance into the reactor vessel through a connecting pipe connected to the reactor vessel, the connecting pipe comprising: connecting a tubular member in communication with the connecting pipe; introducing an inert gas into an internal space of the tubular member from a gas introduction pipe connected to an outer peripheral surface of the tubular member, and inserting a tip end of the lance through an opening of the tubular member having a seal member while continuing to introduce the inert gas into the internal space; A gas collection method comprising the steps of:

2. a pressure of the inert gas introduced into the internal space from the gas introduction pipe is equal to or higher than the pressure inside the reaction vessel at a position where the gas generated inside the vessel is sampled; The gas sampling method according to claim 1.

3. and collecting the gas generated in the container by sucking it with a gas aspirator through an intake port provided at the tip of the lance.

3. The gas sampling method according to claim 1 or 2.

4. The reaction vessel has a high temperature and pressure inside.

3. The gas sampling method according to claim 1 or 2.

5. The reaction vessel has a high temperature and pressure inside. The gas sampling method according to claim 3.

6. A gas sampling device that inserts a lance into a reaction vessel through a connection pipe connected to the reaction vessel, and samples gas generated in the reaction vessel, a tubular member that is detachably connected to the connection pipe and communicates with the connection pipe, and has an opening that has a seal member and into which the tip end of the lance is inserted; a gas introduction pipe connected to an outer peripheral surface of the tubular member for introducing an inert gas into an internal space of the tubular member; A gas sampling device comprising:

7. a pressure of the inert gas introduced into the internal space from the gas introduction pipe is equal to or higher than the pressure inside the reaction vessel at a position where the gas generated inside the vessel is sampled; 7. The gas sampling device of claim 6.

8. a gas suction device that sucks the gas generated in the container through an intake port provided at the tip of the lance; 8. The gas sampling device according to claim 6 or 7.

9. The reaction vessel has a high temperature and pressure inside.

8. The gas sampling device according to claim 6 or 7.

10. The reaction vessel has a high temperature and pressure inside.

9. The gas sampling device of claim 8.

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