WO2016006335A1

WO2016006335A1 - Vapor pipe break detection device

Info

Publication number: WO2016006335A1
Application number: PCT/JP2015/064912
Authority: WO
Inventors: 英一中川; 中野　修
Original assignee: 住友金属鉱山株式会社
Priority date: 2014-07-08
Filing date: 2015-05-25
Publication date: 2016-01-14
Also published as: JP2016017820A; PH12016500901A1; PH12016500901B1; JP5871033B2

Abstract

Provided is a vapor pipe break detection device for the early detection of damage to a vapor pipe through which vapor contaminated with a damaging substance flows. The vapor pipe break detection device comprises a vapor pipe 1 through which vapor flows, a detection pipe 2 provided so as to surround the outer periphery of the vapor pipe 1, and a temperature detector 4 having a sensing unit 4a for detecting the presence or absence of blow-out vapor, the sensing unit 4a facing a vapor retaining space 3 between the outer peripheral surface of the pipe 1 and the inner peripheral surface of the detection pipe 2. If the vapor pipe 1 is damaged and vapor escapes from the damaged portion, even if the damage is minor, vapor enters the vapor retaining space 3 surrounded by the vapor pipe 1 and the detection pipe 2 outside the vapor pipe 1. The detection of the vapor by the temperature detector 4 makes it possible to identify damage at an early stage, allowing the vapor pipe 1 to be repaired while damage to the vapor pipe 1 is still minor. Accordingly, apparatuses provided downstream and upstream of the vapor pipe 1 do not have to be stopped, resulting in an increase in the rate of operation of equipment.

Description

Steam pipe breakage detector

The present invention relates to a steam pipe breakage detection device. More specifically, the present invention relates to a steam pipe breakage detection device for early detection of damage to a steam pipe through which steam mixed with various harmful substances passes.

An example of a steam pipe through which steam mixed with a harmful substance passes will be described below.
In hydrometallurgical equipment based on high-temperature pressurized sulfuric acid leaching of nickel oxide ore, the nickel oxide ore slurry is leached under high-temperature pressure and then depressurized with a flash vessel to further remove the leaching residue and remove impurities It is processed into products such as nickel sulfide, electric nickel, and nickel briquettes through a refining process.
Leaching under high temperature and pressure is often carried out at a temperature of 200 ° C to 300 ° C for the purpose of ensuring a high nickel leaching rate, and the steam recovered at the time of depressurization in the subsequent flash vessel becomes high temperature. The load on the steam recovery pipe for recovering the steam is very high.

In particular, in the above equipment, the harmful substances such as acid mist and slurry are carried over to the steam recovery pipe together with the recovered steam, so that the environment where corrosion and wear are likely to progress. Therefore, it is common to use a thick pipe made of a highly corrosion-resistant material for the steam recovery pipe. In addition, systematic inspection, replacement, and repair are indispensable for such high-load steam recovery piping.

However, sometimes the steam recovery pipe breaks faster than expected and the high temperature and high pressure steam erupts. When such a situation occurs, the operation of the smelting facility will be stopped immediately because it is necessary to lower the temperature and pressure of the pressurized reaction vessel for safety and repair of the steam recovery pipe. For this reason, a great opportunity loss occurs.
In view of the above circumstances, there has been a demand for a method of detecting the breakage of the steam recovery pipe at an early stage. As a technique for detecting such breakage of the steam pipe, there is the following conventional technique.

Japanese Patent Laid-Open No. 11-218002 (Patent Document 1) discloses a method for early detection of steam leakage from a casing, a main steam valve, or piping of a steam turbine. In this prior art, an elongated detection tube is extended from a specific location such as a flange where steam may leak, and a humidity sensor is arranged at the other end of the detection tube, and the humidity sensor detects the leaked vapor. I have to.

In this prior art, there is a problem that only a steam leak from a specific place where a detection pipe is attached can be detected, and a steam leak from an unspecified place of a long steam pipe cannot be detected.
In addition, because the humidity sensor's heat resistance is not high, an elongate detector tube is used to lower the steam temperature, but it takes time while the steam passes through the elongate detector tube. There is a problem that time delay occurs. In this case, the abnormality may not be detected while the steam pipe is small in damage.
Furthermore, when the vapor contains a harmful substance such as slurry, the detection tube is likely to be clogged, and in this case, abnormalities such as vapor leakage may not be detected regardless of the magnitude.

Japanese Utility Model Publication No. 64-000593 (Patent Document 2) describes a steam leaked by a humidity sensor provided in a heat insulation wall, surrounding a valve that is likely to cause a steam leak with a heat insulation wall, and installing a steam intake casing on the heat insulation wall. To detect. In the casing, heat absorbing fillers such as glass fiber for lowering the temperature of high-temperature steam and shielding plates that cause a labyrinth effect are attached, and only the steam that passes through these comes in contact with the humidity sensor. Yes.

However, this conventional example has a problem that only a steam leak from a specific place such as a valve in which steam leaks can be detected, and a steam leak from an unspecified place of a long steam pipe cannot be detected.
In addition, the heat resistance of the humidity sensor is not high, and for the purpose of lowering the steam temperature, an endothermic filler and a shielding plate are put in the sensor casing, but when harmful substances such as acidic mist and slurry adhere to these. The steam leak itself cannot be detected. In this case, not only the early detection of the steam leakage but also the abnormality of the steam leakage itself may not be detected.

As described above, since the prior arts of

Patent Documents

1 and 2 can only detect steam leakage from a specific limited location, they cannot cope with steam leakage from breakage occurring somewhere in a long pipe. There was a problem that steam leaks could not be detected early. For this reason, although it was necessary to immediately start the temperature lowering / lowering operation of the pressurized reaction vessel simultaneously with the occurrence of the ejection of the high-temperature and high-pressure steam due to the piping damage, such a rapid measure could not be taken. As a result, it was not possible to prepare carefully for the repair, and it was not possible to prepare a repair method that would minimize the repair time. Therefore, the problem that the repair took a long time and caused a great opportunity loss still remained.

Japanese Patent Laid-Open No. 11-218002 Japanese Utility Model Publication No. 64-000593

In view of the above circumstances, it is an object of the present invention to provide a steam pipe breakage detecting device that detects breakage of steam pipes that send steam containing various harmful substances at an early stage.

A steam pipe breakage detecting device according to a first aspect of the present invention includes a steam pipe for sending steam, a detection pipe arranged so as to surround an outer periphery of the steam pipe, an outer peripheral surface of the steam pipe, and an inner part of the detection pipe It is characterized by comprising a steam detector in which a sensing part for detecting the presence or absence of ejected steam is faced in a steam storage space between the peripheral surface.
The steam pipe breakage detecting device of the second invention is characterized in that, in the first invention, the detection pipe is closed at both ends by end plates.
The steam pipe breakage detecting device according to a third aspect of the present invention is characterized in that, in the second aspect of the invention, the steam detector is a temperature detector having a sensing portion facing the steam storage space.
A steam pipe breakage detecting device according to a fourth invention is characterized in that, in the third invention, the steam pipe is a pipe in which a harmful substance may be mixed in the steam.
The steam pipe breakage detecting device according to a fifth aspect of the present invention is characterized in that, in the fourth aspect, the steam pipe is a steam recovery pipe of a flash vessel.

According to the first invention, even if the steam pipe is damaged and its level is small, if the steam spouts from the damaged part, the steam enters the steam storage space surrounded by the steam pipe and the detection pipe outside the steam pipe. By detecting this with a steam detector, it is possible to recognize the occurrence of damage at an early stage of damage. For this reason, since damage to the steam pipe can be repaired slightly, it becomes unnecessary to stop the front and rear devices of the steam pipe, and the operating rate of the equipment is improved.
According to the second invention, when even a small amount of steam is ejected from the damaged part of the steam pipe, the temperature of the steam storage space in which the steam is retained rises in a short time. Sensitive detection of damage to steam piping.
According to the third invention, the steam and the harmful substance are sent into the steam pipe, but even if the harmful substance enters the steam storage space, it does not flow at high speed even if the steam storage space is filled. Therefore, it does not damage the sensor or cause malfunction. In addition, since harmful substances are not released from the detection pipe, work safety is ensured and the external environment is not contaminated.
According to the fourth aspect of the invention, harmful substances such as strongly acidic mist and slurry droplets are sent to the steam recovery pipe of the flash vessel. Even if these harmful substances enter the vapor storage space, the vapor storage space is filled. Even if it does, it will not flow at high speed, so it will not damage the sensor or cause it to malfunction. In addition, since harmful substances are not released from the detection pipe, work safety is ensured and the external environment is not contaminated.

It is principal part sectional drawing of the steam piping breakage detection apparatus which concerns on one Embodiment of this invention. FIG. 2 is a schematic side view of the steam pipe breakage detection device shown in FIG. 1. It is explanatory drawing of the hydrometallurgical installation with which the steam piping breakage detection apparatus of this invention is applied.

(Structure of steam pipe breakage detector)
Hereinafter, the steam pipe breakage detection device of the present embodiment will be described with reference to the drawings.
1 and 2, 1 is a steam pipe for sending steam, and 2 is a detection pipe for detecting jetted steam. The steam pipe 1 is a pipe used for supplying and collecting steam in various plants. The diameter, inner thickness, and material of the steam pipe 1 may be arbitrarily selected according to the purpose of use. If high-temperature and high-pressure steam is passed, the pipe has a high corrosion resistance and a thick wall. Good. Even if the steam pipe 1 is small during operation, if the steam pipe 1 is damaged, the steam inside may be ejected to the outside.

The detection pipe 2 is arranged so as to surround the outer periphery of the steam pipe 1. Normally, both the

pipes

1 and 2 are arranged concentrically, but it is not necessary to restrict them concentrically. Although the diameter, inner thickness, and material of the detection pipe 2 can be arbitrarily selected, it is not always necessary to use a pipe as strong as the steam pipe 1 because steam does not always pass therethrough. However, pipes of the same material and thickness can be used.
It suffices if a space is formed between the outer peripheral surface of the steam pipe 1 and the inner peripheral surface of the detection pipe 2, and this space is used as a steam storage space 3 used for detecting the temperature by stopping the steam generated by the damage to the steam pipe 1. The

The length of the detection pipe 2 may be arbitrary, and may be provided over the entire length of the steam pipe 1, or may be limited to a portion where damage is likely to occur.
As shown in FIG. 2, both ends of the detection pipe 2 are closed by fixing the end face plate 22 to the cylindrical body 21.
When configured in such a closed space, the steam spouted from the damaged part of the steam pipe 1 fills the steam storage space 3 which is a closed space and raises the temperature of the space in a short time. Or the abnormal situation of a vapor | steam ejection can be detected in a short time.
However, it is not necessary to completely seal the storage space 3, and there may be some openings. Of course, in this case as well, it is premised that the occurrence of breakage of the steam pipe 1 or the abnormal state of steam ejection can be detected in a short time.

The end face plate 22 of the detection pipe 2 is preferably removable from the cylinder 21. As a method for enabling removal, a means for fixing the flange 23 to the cylinder 21 and bolting the end face plate 22 to the flange 23 can be exemplified. However, the present invention is not limited to this, and any means can be used without any particular limitation. Can do.
As described above, when the end face plate 22 is removable, the end face plate 22 can be removed during repair work, and the steam pipe 1 can be easily removed and the detection pipe 2 can be easily removed.

Since the detection pipe 2 is arranged so as to surround the steam pipe 1, a support column of the detection pipe 2 may be necessary to secure the steam storage space 3. If the detection pipe 2 shown in FIG. 2 is short, it can be supported only by the end face plate 22, but if it is long, a support column inserted between the detection pipe 2 and the steam pipe 1 may be provided.
It is preferable to use ceramics, bricks, or the like that are heat resistant and have little heat conduction or the like. In the case of using a metal material, it is preferable to reduce the heat flow from the steam pipe 1 to the detection pipe 2 by making the column cross-sectional area as small as possible.

The size of the steam storage space 3 is arbitrarily selected from the viewpoint of making it easy to grasp the temperature change in the steam storage space 3 or from the viewpoint of making the size easy to work when replacing the damaged steam pipe 1. Can do. For example, when the steam temperature is high, the volume of the steam storage space 3 may be increased, and when the steam temperature is low, the volume may be decreased. When the volume of the vapor storage space 3 is large, secondary failure does not occur in the temperature detector 4 and the like which will be described later even if high-temperature and high-pressure steam is filled. When the volume of the vapor storage space 3 is small, even if the vapor is relatively low temperature or the amount of ejection is small, it is easy to reliably detect a temperature rise. In addition, the length and shape of the steam storage space 3 may be appropriately selected in consideration of installation conditions such as the length and thickness of the steam pipe 1 and the degree of curvature of the steam pipe 1.

In the steam storage space 3, a steam detector for detecting the ejected steam is disposed. As the steam detector in the claims, any detector can be used as long as it detects leakage or ejection of the ejected steam. In the present embodiment, the temperature detector 4 is used as a vapor detector. The temperature detector 4 is attached to the detection pipe 2 with an appropriate attachment, for example, a flanged pipe 5. The sensing unit 4 a of the temperature detector 4 is disposed so as to face the vapor storage space 3 from the detection pipe 2. The sensing unit 4a is separate from the temperature detector body, and may be a separate type connected by a lead wire or the like, or may be an integrated type in which a long rod-like sensing unit 4a is coupled to the temperature detector body. Good.

In the present invention, the structure of the temperature detector 4 is not particularly limited, as long as the temperature in the steam storage space 3 can be measured during steady operation (when steam does not leak). If the temperature detector 4 uses a thermocouple such as a thermocouple that detects temperature information electrically, and the steam leak is monitored by this electrical signal, automatic steam leak monitoring is possible. This is preferable because it becomes possible.

In the embodiment of FIG. 2, the temperature detector 4 is attached to the long detection pipe 2 at one place, but two or more places may be attached, and the number of attachments is arbitrary.

Next, a method for using the steam pipe breakage detection device of the present embodiment will be described.
In the steam pipe 1, when breakage that causes steam leakage occurs due to various problems, steam is ejected from the damaged portion. The leaked steam first fills the steam storage space 3. The temperature rise due to the vapor filling is detected by the temperature detector 4.
Since the steam storage space 3 is a closed space, the temperature rise due to the steam filling occurs sensitively. Therefore, even if the damage is small, it can be detected quickly. Therefore, before the damage becomes large, in other words, appropriate repairs can be made before a major accident occurs.

The following can be illustrated as a repair method.
a) Remove the detection pipe 2, then remove the damaged steam pipe 1 and replace it with a new steam pipe 1.
b) In the above method a), instead of replacing the steam pipe 1, repair is performed by a method such as applying a repair member or the like to the damaged portion and welding.
c) Without removing the detection pipe 2, pull out the damaged steam pipe 1 from the detection pipe 2 and replace it with a new steam pipe 1 or repair the damaged part.
In addition to the above, various methods can be arbitrarily employed.

Various substances are included in the injurious substances referred to in the claims, and examples include acidic mist and slurry. When these harmful substances are contained in the steam, these harmful substances are also ejected from the damaged portion into the steam storage space 3 together with the steam to be filled. However, since the vapor storage space 3 is a closed space and does not flow at a high speed in the inside thereof, the sensing unit 4a of the temperature detector 4 may be damaged, or the surroundings of the sensing unit 4a may become dysfunctional. There is no.

(Application example to wet smelting equipment)
The most typical application example in the present invention is application to a hydrometallurgy facility of nickel oxide ore.
Hereinafter, this application example will be specifically described with reference to FIG.
In the present embodiment, steam generated when the pressure of the pressure-reacted vessel 13 is used to depressurize the liquid obtained by leaching nickel oxide ore with sulfuric acid under high temperature and pressure is supplied to the pressurized reaction vessel 13. This is applied to the steam recovery pipe A used when the nickel oxide ore slurry is heated for pressurization.

This will be described in more detail with reference to FIG.
The slurry S is heated and pressurized in the slurry preheating tank 11 and is pushed into the pressurized reaction vessel 13 by the pump 12, and at the same time, sulfuric acid, reaction air (oxygen-enriched air), etc. (not shown) are added, The metal is leached to the liquid phase side of the slurry, and then the temperature is lowered and reduced by the flash vessel 14 and transferred to the neutralization step 15 and the like in the subsequent step.
When the temperature of the flash vessel 14 is lowered, the water vapor corresponding to the pressure drop is generated quite violently. A steam recovery pipe A is provided for recovering the steam and sending it to the slurry preheating tank 11 for recovery.

Hereinafter, further details will be described for each apparatus.
1) Nickel oxide ore slurry S
Raw ore after mining (for example, nickel grade is about 1.0 to 2.0%) is formed into slurry S having a predetermined particle size and concentration by multi-stage classification (screening) and crushing stage. It is collected and transferred to the next leaching process.
2) Slurry preheating tank 11
The ore slurry S is heated while the moisture of the ore slurry S is well maintained by directly contacting the ore slurry S and the water vapor that are counterflowing.

3) Pump 12
The ore slurry S is heated and raised to about 2 to 6 MPa · G and about 200 to 300 ° C. in a preheating tank 11 (preheater), and is provided to push this into the next pressurized reaction vessel 13.
4) Pressurized reaction vessel 13
In the high-pressure acid leaching step, the ore slurry S obtained in the pretreatment step is gradually heated and pressurized in the preheating tank 11 and then supplied to the pressurized reaction vessel 13 (= autoclave). In the same manner, sulfuric acid that has been heated and pressurized in the same manner is added to the raw material slurry S, and stirred at 220 to 280 ° C. to leached valuable metals at high temperature and pressure. In addition, the obtained leaching slurry S is sent to the flash vessel 14, and the temperature is lowered to normal temperature and normal pressure.

5) Flash vessel 14
The flash vessel 14 includes a cylindrical body with a bottom, and a slurry charging inlet and a steam discharge port are provided in a ceiling portion where the upper portion of the barrel is closed, and a slurry discharge port is provided in the trunk portion.
A slurry charging pipe for charging the leached slurry S that has been lowered to a predetermined temperature and a predetermined pressure into the flash vessel 14 is connected to the slurry charging inlet, and a flash vessel 14 is connected to the slurry outlet. A slurry discharge pipe for discharging the slurry charged in the inside is connected, and a steam recovery pipe A for recovering the steam generated in the flash vessel 14 as the slurry is charged is connected to the steam outlet. Has been.

The steam pipe breakage detection device of the present invention is applied to the steam recovery pipe A shown in FIG. The symbol I in the figure indicates the cross-sectional part of FIG. The steam pipe breakage detecting device having a double pipe structure shown in FIGS. 1 and 2 may be applied over the entire length of the steam recovery pipe A shown in FIG. It may be selected and applied.

In the embodiment applied to the steam recovery pipe A in FIG. 3, steam at around 200 ° C. passes through the steam pipe 1, and the outer surface of the steam recovery pipe is around 200 ° C. Although the temperature of the vapor storage space 3 shown in FIG. 2 depends on the distance from the flash vessel 14, the detection pipe 2 is in contact with the outside air, so the temperature of the vapor storage space 3 is between the outside air temperature and 200 ° C. For example, the temperature is stable within a range of ± 5 ° C.
When steam leakage occurs, the temperature of the steam storage space 3 rapidly increases, for example, by 10 ° C. or more. By monitoring this temperature change, it is possible to detect a steam leak caused by damage to the steam pipe 1.

(Advantages of steam pipe breakage detector)
The steam pipe breakage detecting device according to the present invention starts repair work for the steam pipe 1 as soon as a steam leak is detected. At that time, the steam pipe breakage detecting apparatus has the following four effects.
(1) Early detection of steam pipe 1 breakage is possible.
When the steam pipe 1 is damaged, the steam leaks into the steam storage space 3 and the temperature rises abruptly. This rapid temperature change is detected, so that the steam pipe 1 can be detected early.

(2) Repair and replacement of the damaged steam pipe 1 can be carried out by a procedure prepared in advance.
As described in (1) above, early detection of damage to the steam pipe 1 is possible. Therefore, there is a time delay from discovery to the start of repair, and repair can be performed according to a procedure prepared in advance, so that the repair process can be shortened compared to the conventional method.

(3) For the replacement of the steam pipe 1 or the like, it is necessary to stop the operation of the front and rear devices referred to in the claims, that is, the devices connected before and after the steam pipe 1. In the embodiment applied to the hydrometallurgical equipment, the temperature reduction and pressure reduction of the pressurized reaction vessel 13 which is an example of the pre-rear apparatus is performed first, but since the repair of the steam pipe 1 is started after the treatment, the repair is performed. This can be done in a short time, and operational opportunity loss can be greatly reduced.
(4) Since the steam mixed with high-temperature and strongly acidic mist and slurry splashes is not released outside the detection pipe 2, that is, to the outside air, the operational safety is improved and the environment is improved. The adverse effect of is reduced.

(Example 1)
Example 1 is a steam pipe breakage detecting device having the configuration shown in FIGS. 1 and 2 installed in the steam recovery pipe A shown in FIG. In this steam pipe breakage detector, the indicated value of the temperature detector 4 had been stable with a fluctuation range of ± 3 ° C until then, but suddenly rose about 15 ° C. Since no damage was found in the detection pipe 2 and no steam eruption was found, after repair preparation of the steam recovery pipe A and a meeting between the repair procedures, the pressurized reaction vessel 13 was cooled and depressurized to break the steam pipe. 1 repair was done.
The cause of damage was perforation due to thinning, so it was replaced with a spare part that had been prepared. At this time, the operation was stopped for 24 hours.

(Comparative Examples 1, 2, 3)
The case where it operates with the conventional one steam recovery piping without applying the steam piping breakage detection device of the present invention is taken as a comparative example. In the comparative example, because the steam pipe 1 was damaged and the steam spouted out, the pressurized reaction vessel 13 was immediately cooled down to repair the steam pipe 1. Because the cause of the damage was perforation due to thinning, patching (emergency repair) was applied to the perforated part and the thinned part. Table 1 shows the time during which the operation was stopped.

In Example 1, since the steam recovery pipe damage was detected at an early stage, the operation was stopped according to the procedure prepared in advance and repaired. For this reason, the repair process proceeded smoothly and the operation stoppage time was minimized.
On the other hand, in Comparative Examples 1, 2, and 3, after the steam pipe damage was detected, the operation of the pressurized reaction vessel 13 must be stopped immediately, so that it was not possible to take time to prepare for repair. Worked. For this reason, the repair time could not be shortened.

In Comparative Examples 1 to 3, the repair time varies depending on the time when the steam pipe is damaged and the location of the damage, and the sprayed steam adheres to the surrounding area and impairs safety during work. Although there was a problem, Example 1 did not cause such inconvenience.

1 Steam piping 2 Detection piping 3 Steam storage space 4 Temperature detector A Steam recovery piping

Claims

Steam piping for sending steam;
A detection pipe arranged so as to surround the outer periphery of the steam pipe;
A steam pipe comprising: a steam detector facing a sensing unit for detecting the presence or absence of jetted steam in a steam storage space between an outer peripheral surface of the steam pipe and an inner peripheral surface of the detection pipe Damage detection device.
The steam pipe breakage detection device according to claim 1, wherein both ends of the detection pipe are closed by end face plates.
The steam pipe breakage detection device according to claim 2, wherein the steam detector is a temperature detector with a sensing unit facing the steam storage space.
The steam pipe breakage detection device according to claim 3, wherein the steam pipe is a pipe in which a harmful substance may be mixed into the steam.
The steam pipe breakage detection device according to claim 4, wherein the steam pipe is a steam recovery pipe of a flash vessel.