JP7655154B2 - Flue sealing balloon and flue sealing method - Google Patents

Description

The present invention relates to a flue gas flue in a flue gas recovery process of copper smelting, more specifically, to a flue located near a conversion process in which sulfurous acid (SO ₂ ) gas generated in the copper smelting is converted into sulfuric acid gas (SO ₃ ), and to a flue sealing method using the flue sealing balloon.

Sulfur dioxide ( _SO2 ) gas, which is an exhaust gas generated in copper smelting, is purified in an exhaust gas purification process consisting of a humidification tower, a scrubbing tower, a mist cotter, and a drying tower, and then introduced into a converter via a flue and a main blower. In the converter, the sulfur dioxide gas is converted into sulfuric acid ( _SO3 ) gas by a vanadium pentoxide catalyst, and then in an absorption tower, the sulfuric acid gas is brought into gas-liquid contact with circulating sulfuric acid to absorb the sulfuric acid gas, and the sulfur dioxide gas is finally recovered as sulfuric acid.

Damage such as holes caused by corrosion from the sulfuric acid mist flowing from the converter and cracks caused by expansion and contraction due to temperature changes when the equipment is shut down can occur in the flue around the converter. If such holes, cracks or other damage exist, there is a risk of sulfur dioxide gas leaking from the flue, so the equipment must be shut down as soon as possible and the damaged areas repaired. Most such damaged areas can be repaired from the outside of the flue, but in some cases it is better to repair from the inside of the flue.

In addition, if sulfuric acid mist adheres to the impeller of a blower installed in the flue path near the converter for a long period of time, it may cause malfunctions in the blower, making it necessary to urgently maintain the blower, such as replacing the impeller.

In these cases, workers must carry out repair work from inside the facility (inside the flue) to fix any damaged areas in the flue or malfunctioning of the blower. However, even if the blower is stopped to carry out these repair work from inside the facility, white sulfuric acid gas will flow back from the converter into the flue, filling it. This makes it difficult to see inside the flue, and makes it extremely difficult for workers to carry out repair work while wearing a gas mask with a respirator.

For this reason, when repair work is carried out inside the equipment near the converter, gas purging is required to remove the sulfuric acid gas inside the flue. However, in this case, a long-term shutdown of about one week is required, including the heating process after the repair, resulting in significant operational and energy losses.

In addition, JP 2006-226372 A discloses an example of a fluid blocking device for blocking the flow of fluid in a pipeline that uses a bag-shaped balloon that can be inflated until it comes into contact with the inner wall surface of the pipeline.

JP 2006-226372 A

The present invention aims to provide a simple flue sealing balloon and a flue sealing method using this flue sealing balloon, which allows repair work to be performed inside the equipment to repair damaged areas in the flue or malfunctions in equipment such as a blower impeller while blocking sulfuric acid gas, without requiring long-term shutdowns due to gas purging, etc.

The flue sealing balloon of one embodiment of the present invention is made of an elastomer and has a cylindrical portion, side surfaces that close both axial ends of the cylindrical portion, an air supply port provided on one of the side surfaces, and a handle provided at a circumferential location on the outer circumferential surface of the cylindrical portion, the balloon being transportable into the flue and capable of expanding until the outer circumferential surface of the cylindrical portion comes into contact with the inner wall surface of the flue.

The elastomer is preferably an acid-resistant rubber.

One aspect of the present invention relates to a flue sealing method for sealing a flue that has at least one manhole that allows access to the inside when repairing a repair target within the flue.

In particular, a flue sealing method according to one aspect of the present invention comprises the steps of:
Using two flue sealing balloons of the present invention,
Transporting and installing the two flue sealing balloons through the manhole to both sides of the section of the flue that includes the manhole and the repair target, and
an inflation fluid is fed to each of the two flue-sealing balloons through the air supply port to inflate the balloons until the outer circumferential surface of the cylindrical portion comes into contact with the inner wall surface of the flue, thereby sealing the flue.
This includes:

After sealing the flue, gas present in the section can be removed through the manhole.

It is preferable that the manholes are installed in at least two locations along the flue path.

It is preferable that the repair target is equipment such as a blower installed in the flue path, and that the two locations are located on either side of the flue.

In one embodiment of the present invention, the exhaust gas and the gas present in the section are sulfuric acid gas and/or sulfur dioxide gas. In this case, the flue is called a sulfuric acid flue.

By applying the flue sealing balloon of one embodiment of the present invention and the flue sealing method using this balloon, the flue can be easily sealed in a short time before sulfuric acid gas flows back into the flue from a converter or the like. It is also possible to quickly remove small amounts of sulfuric acid gas that flow into the seal and remain. This makes it possible to repair damaged areas of the flue and defects in equipment such as blowers within the equipment without requiring long-term operation shutdowns. For this reason, the industrial value of this invention is extremely great.

FIG. 1 is a perspective view of a flue sealing balloon according to one embodiment of the present invention. FIG. 2 is a schematic diagram for explaining the installation of a flue sealing balloon according to one embodiment of the present invention when repairing a damaged portion of a flue using the balloon. FIG. 3 is a schematic diagram for explaining the installation of a flue sealing balloon according to one embodiment of the present invention when repairing a malfunction of a blower impeller of a blower located in the flue path.

One embodiment of the present invention will be described below with reference to the drawings as appropriate.

[Flue sealing balloons]
1 shows a flue sealing balloon 1 according to one embodiment of the present invention. The flue sealing balloon 1 of this example is made of an elastomer and has a generally cylindrical shape.

The balloon 1 comprises a cylindrical portion 2, side surfaces 3 that close both axial ends of the cylindrical portion 2, an air supply port 4 provided on one of the side surfaces 3, and a handle 5 provided at one circumferential location on the outer circumferential surface of the cylindrical portion 2 at a position spaced apart in the axial direction.

The material of the balloon 1 is an elastomer containing rubber, and an appropriate elastomer can be selected from the viewpoints of elasticity and expansion. However, considering the use in the flue 6 (see Figures 2 and 3) where sulfuric acid gas and/or sulfurous acid gas is present and the contact with the inner wall surface of the flue 6, it is preferable that the elastomer be acid-resistant rubber. Examples of acid-resistant rubber include chlorosulfonated polyethylene, butyl rubber, fluororubber, ethylene propylene rubber, chloroprene rubber, and nitrile rubber.

When inflated, the balloon 1 has an overall cylindrical shape. Usually, the flue gas flue 6 in the flue gas recovery process of copper smelting has a cylindrical shape with a circular cross section, and the balloon 1 expands into a cylindrical shape, so that its outer circumferential surface can come into close contact with the inner wall surface (inner circumferential surface) of the flue 6. However, by adjusting the thickness of the balloon 1, it is possible to apply the balloon 1 to flue gases other than those with a cylindrical cross section. In addition, unlike a bag-shaped balloon, the balloon 1 has a cylindrical shape, so that it can expand in the circumferential direction while suppressing excessive expansion in the axial direction in the flue 6, and does not require a reinforcing member such as a restraining plate. This makes it possible to appropriately expand the balloon 1 at a predetermined location in the flue 6.

When the balloon 1 is inflated, the cylindrical portion 2 has a cylindrical shape with an outer diameter that is approximately the same along its axial direction. The outer diameter of the cylindrical portion 2 is larger than the inner diameter of the flue 6. The outer diameter of the cylindrical portion 2 is selected arbitrarily depending on the size of the flue 6 to which it is applied. It is sufficient that the cylindrical portion 2 has an outer diameter that allows it to expand at least until it comes into contact with the inner wall surface of the flue 6.

The axial length of the cylindrical portion 2 is basically arbitrary, so long as the sealing of the flue 6 by the balloon 1 is ensured. Therefore, from the viewpoint of transportability, it is preferable that the axial length of the cylindrical portion 2 is as short as possible, so long as the sealing is ensured. The axial length of the cylindrical portion 2 is preferably equal to or less than the outer diameter of the cylindrical portion 2, more preferably 0.5 to 0.9 times the outer diameter of the cylindrical portion 2, and even more preferably 0.6 to 0.8 times the outer diameter of the cylindrical portion 2.

The side surfaces 3 are generally disc-shaped and are provided to close both axial ends of the cylindrical portion 2. Each side surface 3 has approximately the same outer diameter as the cylindrical portion 2 when the balloon 1 is inflated. By providing the side surfaces 3, the balloon 1 is able to expand into a cylindrical shape because it preferentially expands radially during the transition from a folded state to an inflated state.

The thickness of the cylindrical portion 2 and the side surface 3 is determined appropriately taking into consideration the type of elastomer, the overall size of the balloon 1, its inflatability, its foldability when deflated, and ease of transport. For example, the thickness is preferably 0.3 mm to 3.0 mm, and more preferably 0.5 mm to 1.5 mm.

In the present example, the balloon 1 is provided with two handles 5 at one circumferential location on the outer circumferential surface of the cylindrical portion 2, spaced apart in the axial direction. Considering the portability of the balloon 1 in its contracted state, the number of handles 5 is preferably two or more, so that the balloon 1 can be easily transported by holding both handles 5 or one of the handles 5 and the cylindrical portion 2 with both hands. The size and thickness of the handles 5 are set arbitrarily in consideration of the portability of the balloon 1, as long as they do not impede the sealing property of the balloon 1 when it is inflated. For example, the size of each handle 5 is preferably 200 mm x 200 mm. The thickness of each handle 5 is preferably, for example, 0.3 mm to 3.0 mm, and more preferably 0.5 mm to 1.5 mm.

In this example, the balloon 1 is provided with an air supply port 4 and an exhaust port 7 on one of the two side surfaces 3. In this example, the air supply port 4 consists of an opening on the side surface 3 and an attachment connected and fixed to this opening. When the balloon 1 is inflated and during use, it is connected to an attachment provided at the tip of the air supply hose 14. This state continues while the balloon 1 is in use. As a result, during use, the internal pressure within the balloon 1 is maintained so that the balloon 1 is in close contact with the inner wall surface of the flue 6. The air supply port 4 can also be provided with a valve body that prevents the inflation fluid, air or an inert gas such as nitrogen gas, from flowing out from inside the balloon 1 to the outside.

In the balloon 1 of this example, an exhaust port 7 is provided separately on one side 3 at a position away from the air supply port 4. The exhaust port 7 also consists of an opening provided on the side 3 and an attachment connected and fixed to this opening. When the balloon 1 is in storage or in an inflated state, a closing flange 8 is attached to the attachment of the exhaust port 7. When the balloon 1 is deflated, the closing flange 8 can be removed to discharge the inflation fluid from inside the balloon 1.

The materials constituting the air inlet 4, exhaust outlet 7, and closing flange 8 are selected from known materials.

The balloon 1 of this example has appropriate elasticity and expandability, and preferably also has acid resistance, so it can be transported and applied to a flue 6 where sulfur dioxide gas and/or sulfuric acid gas is present, such as the flue 6 of exhaust gas in the exhaust gas recovery process of copper smelting. In addition, the handle 5 allows the balloon 1 in a folded state to be easily carried into the flue 6. Therefore, by applying the balloon 1 according to the inner diameter of the flue 6, it is possible to install the balloon 1 at a necessary location in the flue 6 without the need for reinforcing members, and by expanding the balloon 1 into a cylindrical shape until it contacts the inner wall surface of the flue 6, it is possible to properly seal the flue 6.

[How to seal the flue]
FIG. 2 is a schematic diagram of a flue sealing method according to one embodiment of the present invention, and FIG. 3 is a schematic diagram of a flue sealing method according to another embodiment of the present invention.

The flue sealing method of this example makes it possible to seal the flue 6 when repairing a repair target within the flue 6 (such as a damaged area 10 in the flue 6 or the impeller of a blower 11) in a flue 6 that has at least one manhole 9 that allows access to the inside.

In particular, the flue sealing method of this example uses two of the flue sealing balloons 1 of the present invention described above. Then, the two sulfuric acid flue sealing balloons 1 are transported through the manhole 9 to both sides of the section of the flue 6 that includes the manhole 9 and the repair target (repair section 12), and then installed.

As shown in FIG. 2, manholes 9 that allow workers to enter and exit are installed at predetermined intervals in the flue gas flue 6 in the flue gas recovery process of copper smelting. For example, if a damaged area 10 occurs in the flue 6 and repair of the damaged area 10 is required from the inside of the flue 6, the manhole 9 closest to the damaged area 10 is used.

For example, if the flue 6 is located near the upstream side of a converter (not shown) that converts sulfurous acid ( _SO2 ) gas into sulfuric acid gas ( _SO3 ), it takes about one hour for the white sulfuric acid gas to flow back into the flue and fill it after the converter and equipment such as a blower for transporting exhaust gas in the flue are stopped. Therefore, immediately after stopping the equipment, a worker wearing a gas mask with a respirator opens the cover of the manhole 9 and carries the folded balloon 1 through the manhole 9, using its handle 5, to two locations in the flue 6, one before and one after the damaged area 10 and the repair section 12 including the manhole 9.

After the balloon 1 is carried to the installation site and the worker exits through the smoke duct 6, the balloon 1 is inflated by supplying air or an inert gas such as nitrogen gas into the balloon 1 either in advance or at the installation site via an air supply hose connected to the air supply port 4. The inflation fluid for the balloon 1 is selected according to the application and the conditions of the installation site. In this example, air can be used as the inflation fluid.

When inflation fluid is supplied to the balloon 1, the balloon 1 expands into a cylindrical shape as shown in FIG. 1, and its outer periphery comes into contact with the entire inner wall surface of the flue 6, and the outer periphery of the balloon 1 and the inner wall surface of the flue 6 are tightly attached, sealing the flue 6 at two points at the installation location. This prevents gases 13 such as sulfur dioxide and sulfuric acid gas from flowing into the repair section 12, which includes the manhole 9 and the damaged area 10, from both sides.

In this example, the small amount of gas remaining in the repair section 12, specifically the residual gas such as sulfur dioxide gas present in the flue 6 and sulfuric acid gas that flowed in before the balloon 1 was installed, is removed from the repair section 12 by sucking and processing through the manhole 9. This makes it possible to carry out repair work on the damaged area 10 in the repair section 12. In this example, after the repair work is completed, the closing flange 8 fitted into the exhaust port 7 of the balloon 1 is removed to remove the air from the balloon 1, and the worker uses the handle 5 to carry the balloon 1 from the flue 6 to the outside through the manhole 9, completing the work.

As shown in Fig. 2 , when at least one manhole 9 is provided in the flue 6, two balloons 1 are provided to sandwich both the manhole 9 and the damaged area 10 from both sides, thereby sealing the flue 6 and enabling repair of the damaged area 10. However, from the viewpoint of shortening the repair section 12 sandwiched between the two balloons 1, or considering a case where a balloon 1 can be provided on one side of the manhole 9 but there is not enough space to provide the balloon 1 on the other side of the manhole 9, it is preferable that at least two manholes 9 are provided in the flue 6.

More specifically, as shown in FIG. 3, when equipment such as a blower 11 is present in the path of the flue 6 and the repair target is inside the equipment, such as the impeller of the blower 11, it is possible to install a balloon 1 on one side of the manhole 9 farther from the blower 11 to enable access to the equipment on at least one side (the left side in the example of FIG. 3), but it is impossible to install a balloon 1 on the other side of the manhole 9 closer to the blower 11. In such a case, manholes 9 are installed in two positions on both sides of the equipment that may require repair, such as the blower 11, at a predetermined distance from the equipment in the flue 6. In this way, when the repair target is equipment such as the blower 11 installed in the path of the flue 6, it is preferable that at least two positions for installing manholes are located on either side of the equipment in the flue 6.

In this case, the inside of the flue 6 is entered from two manholes 9 of the flue 6 installed near the blower 11, and the balloon 1 is installed and inflated at an appropriate position on at least one side of the blower 11, on the opposite side of the flue 6 from the blower 11. In the example of FIG. 3, the blower 11 can be accessed from the left side of the blower 11, but the blower 11 cannot be accessed because the valve 15 is present on the right side of the blower 11. For this reason, in this example, the balloon 1 is installed on the opposite side of the blower 11 on the left side of the blower 11, and on the opposite side, the balloon 1 is installed on the side of the manhole 9 where the blower 11 and the valve 15 are located, and inflated. In this way, the balloon 1 is installed so that the length of the repair section 12 is as short as possible, and the flue 6 is sealed. Similarly, if necessary, after removing residual gas from the repair section 12, it is possible to repair the inside of the equipment, such as the impeller of the blower 11.

The flue sealing method of this example makes it possible to easily seal the flue 6 in a short time before gas 13, such as white sulfuric acid gas, flows back into the flue 6 from a converter or the like. Therefore, even if gas 13, such as sulfuric acid gas, flows into the repair section 12 during sealing, it is possible to quickly remove the small amount of remaining gas 13 through the manhole 9. Therefore, it is possible to reduce the equipment downtime by about one week compared to repairing the repair area after purging the gas over the entire flue 6.

REFERENCE SIGNS LIST 1 Balloon 2 Cylindrical part 3 Side 4 Air supply port 5 Handle 6 Flue 7 Exhaust port 8 Closing flange 9 Manhole 10 Damaged area 11 Blower 12 Repaired section 13 Gas 14 Air supply hose 15 Valve

Claims (6)

A flue sealing balloon comprising a cylindrical portion, side surfaces closing both axial ends of the cylindrical portion , and two or more handles each of which can be held by a hand, the two or more handles being provided at one circumferential location on the outer circumferential surface of the cylindrical portion at positions spaced apart in the axial direction, the cylindrical portion, the side surfaces, and the two or more handles being made of an elastomer, and an air supply port being provided on one of the side surfaces, the air supply port consisting of an opening provided on the one side surface and an attachment connected and fixed to the opening, the balloon having at least one manhole allowing access to the interior, the balloon being transportable into a flue through which an operator can move within , and capable of being inflated until the outer circumferential surface of the cylindrical portion comes into contact with the inner wall surface of the flue. The flue sealing balloon of claim 1, wherein the elastomer is an acid-resistant rubber. A flue sealing method for repairing a repair target in a flue having at least one manhole that allows access to the inside and in which a worker can move through the inside , comprising:
Using two flue sealing balloons according to claim 1 or 2,
Transporting and installing the two flue sealing balloons through the manhole to both sides of the section of the flue that includes the manhole and the repair target, and
an inflation fluid is fed to each of the two flue-sealing balloons through the air supply port to inflate the balloons until the outer circumferential surface of the cylindrical portion comes into contact with the inner wall surface of the flue, thereby sealing the flue.
A method of sealing a flue comprising: The flue sealing method according to claim 3, further comprising removing gas present in the section through the manhole after sealing the flue. The flue sealing method according to claim 3 or 4, wherein the manholes are installed in at least two locations along the flue path. The flue sealing method according to claim 5, wherein the repair target is equipment installed in the flue path, and the two locations are located on either side of the flue.

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