WO2021160940A1

WO2021160940A1 - A device for online deslagging

Info

Publication number: WO2021160940A1
Application number: PCT/FI2021/050103
Authority: WO
Inventors: Juha Paananen; Ari LAKSOLA
Original assignee: Konetuuli Oy
Priority date: 2020-02-16
Filing date: 2021-02-15
Publication date: 2021-08-19
Also published as: FI129754B; FI20205159A1

Abstract

A device for online deslagging by blasting an explosive (19). A lance tube (10) comprises a grip-side and an explosive-side end section. The explosive (19) is connected to a detonator (17) and a wire (11) extending from the detonator (17) to the grip-side. The device comprises a tubular end piece (14) having open ends, a first end being connectable to the explosive-side end section of the lance tube (10), wherein the detonator (17) and/or the wire (11) travels through the tubular end piece (14) when connected to the device. The second end of the tubular end piece (14) is configured to receive the retainer (18) for the explosive (19). The second end of the tubular end piece (14) is rounded.

Description

A DEVICE FOR ONLINE DESLAGGING

BACKGROUND

This disclosure relates to boiler deslagging, and particularly, a device for online deslagging by explosives. One example of the boiler is a recovery boiler. Deposits build up gradually to the boiler’s inner walls during a pulping process. The boiler may lose its efficiency due to slag deposits. Explosive deslagging creates strong shock waves to blast slag deposits off of the boiler. Many known examples of explosive deslagging require stopping the boiler. In one example this requires also shutting down a pulp mill process, which may be expensive as the production time is lost.

Online deslagging solutions may blast the explosives while the boiler process is running. Some examples may release debris from the blasting assembly into the boiler. The debris may cause deviations in the process. Hot boiler may cause problems to the selected explosives, such as prematurely detonating the explosives when they are introduced to the heat of the running boiler, which is very dangerous to the personnel operating the device. SUMMARY

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any part of this disclosure.

A device for online deslagging by blasting an explosive is disclosed. The device comprises a lance tube that has the explosive attached to its end section. The operator may position the explosive inside the boiler via an access hatch, inspection hatch or other suitable opening that is accessible while the boiler is running. The explosive-side end section of the lance tube is connected to a first end of a tubular end piece. The tubular end piece is made of hard material that withstands the explosions, for example steel or steel alloy. The second end of the tubular end piece is positioned towards the explosive. The second end is open, allowing a detonator and/or a detonator wire to pass through the tubular end piece.

The second end of the tubular end piece is rounded. The rounded end is positioned towards the explosive. Tests have proven that the simple shape, having rounded edge at the second end of the tubular end piece is durable. The tubular end piece withstands several blasts inside the running boiler.

The explosive is in one embodiment attached directly to the second end of the tubular end piece. In one embodiment the explosive is connected to an attenuator positioned between the tubular end piece and the explosive. The attenuator provides distance between the tubular end piece and the explosive, reducing the stress caused by the blast to the tubular end piece. In one example the attenuator protects the tubular end piece from the blast. The attenuator may be a tubular component, allowing the detonator and/or the wire to pass through the attenuator into the explosive.

The explosive is held in place by a retainer. The retainer is in one example an adhesive tape that is wrapped around the tubular end piece, the attenuator and the explosive. In one example the retainer and the attenuator are integrated into the explosive housing, wherein the explosive housing may be pushed onto the tubular end piece.

The device enables online deslagging of boilers, such as recovery boilers. The tubular end piece protects the lance tube. The cleaning process by online deslagging with the device described herein may use relatively small explosives. The lance tube and the tubular end piece are reusable and assembling the device for next blast is simple. Small blasts do not cause damage to the boiler or any device connected to the boiler, for example to control or monitoring devices.

Many of the attendant features will be more readily appreciated as they become better understood by reference to the following detailed description considered in connection with the accompanying drawings. The embodiments described below are not limited to implementations which solve any or all the disadvantages of known deslagging devices.

BRIEF DESCRIPTION OF THE DRAWINGS

The present description will be better understood from the following detailed description read in light of the accompanying drawings, wherein

FIG. 1 illustrates schematically a cross-sectional view of one exemplary embodiment of the device for online deslagging by blasting an explosive;

FIG. 2 illustrates schematically an exploded view having some of the components of the device; and FIG. 3 illustrates schematically one exemplary embodiment of the assembled device.

Like reference numerals are used to designate like parts in the accompanying drawings.

DETAILED DESCRIPTION

The detailed description provided below in connection with the appended drawings is intended as a description of the present examples and is not intended to represent the only forms in which the present example may be constructed or utilized. However, the same or equivalent functions and sequences may be accomplished by different examples.

Although the present examples are described and illustrated herein as being implemented in a recovery boiler, they are provided as an example and not a limitation. As those skilled in the art will appreciate, the present examples are suitable for application in a variety of different types of boilers or furnaces.

FIG. 1 illustrates schematically a cross-sectional view of one exemplary embodiment of the device for online deslagging by blasting an explosive. A lance tube 10 is a longitudinal, hollow tube that the operator uses to position the explosive inside the boiler. The lance tube 10 may made of steel or an alloy suitable for temperatures inside the running boiler. The lance tube 10 has two end sections; a grip-side end section and an explosive-side end section. When operated, the lance tube 10 is inserted to the boiler through an access hatch, an inspection hatch or other suitable opening that is accessible while the boiler is running. The operator holds the lance tube 10 manually at the grip side end section and moves the explosive-side end section inside the boiler to a suitable position for blasting the slag or residual build-up off the walls of the boiler by an explosive 19.

FIG. 2 illustrates schematically an exploded view having some of the components of the device. A tubular end piece 14 is connectable to the lance tube 10, wherein a detonator wire 11 may travel through the lance tube 10 and the tubular end piece 14. The tubular end piece 14 is configured to protect the lance tube 10 from the explosions. Both ends of the tubular end piece are open. A first end is connectable to the explosive-side end section of the lance tube 10. In one embodiment the tubular end piece 14 comprises a thread configured to be connected to the thread on the lance tube 10. Alternatively, or in addition, the tubular end piece 14 comprises a bolt 20 that may be tightened onto the lance tube 10. In one embodiment the connection between the lance tube 10 and the tubular end piece 14 is a sleeve joint secured by the bolt 20. The opposite end of the tubular end piece 14 is rounded. The rounded end of the tubular end piece 14 is facing the explosive 19. The rounded edges are capable of withstanding the impact of multiple explosions. The tubular end piece 14 remains intact after several consecutive blasts. In one embodiment the tubular end piece 14 comprises smooth outer surface, without any edges that might tear apart due to the blast impact. The tubular end piece 14 is in one embodiment made of metal, such as steel. The steel quality may be chosen to be suitable to withstand several blast impacts. The smooth surface refers to a machined or a polished surface.

In one embodiment an attenuator 16 is positioned between the second end of the tubular end piece 14 and the explosive 19. The attenuator 16 protects the tubular end piece 14 from the blast impact. The attenuator 16 is made of material that will disintegrate and/or burn in the boiler, without leaving harmful residues to the pulp process. In one embodiment the attenuator 16 is made of rubber. In one embodiment the attenuator 16 is made of plastic or composite material. In one embodiment the attenuator 16 is made of cardboard. The attenuator 16 comprises an opening allowing the wire 11 and/or the detonator 17 to travel through the attenuator 16 into the explosive 19.

In one embodiment the attenuator 16 is a cylindrical piece having the opening in the middle. The attenuator 16 may comprise a shape suitable to interact with the tubular end piece 14 and/or the explosive 19. In one embodiment the attenuator 16 is a plug between the tubular end piece 14 and the explosive 19. The thickness of the attenuator 16 provides distance between the tubular end piece 14 and the explosive 19. In one embodiment the thickness of the attenuator 16 is between 10 mm and 40 mm. In one embodiment the thickness of the attenuator 16 is between 20 mm and 30 mm.

The explosive 19 is attached to the end of the device by a retainer 18 that is one example of means for connecting the explosive 19 to the cleaning-side end section, wherein the explosive 19 is connected to the detonator 17 and the wire 11 extending from the detonator 17 to the grip-side end section of the lance tube 10. The retainer 18 secures the explosive 19 under the temperatures of the running boiler. The retainer 18 is made of material suitable to withstand temperatures inside the running boiler. In one embodiment the retainer 18 is an adhesive tape that is wound over the explosive 19 and the tubular end piece 14. In one embodiment the adhesive tape is wound over the explosive 19, the attenuator 16 and the tubular end piece 14. The second end of the tubular end piece 14 is configured to receive the retainer 18 for the explosive 19. In one embodiment the outer surface of the tubular end piece 14 is configured to receive suitable amount of adhesive tape to secure the attenuator 16 and/or the explosive 19 to the device. In one embodiment length of the tubular end piece 14 is between 50 mm and 200 mm. In one embodiment width of the adhesive tape is between 20 mm and 100 mm. In one embodiment width of the adhesive tape is between 100 mm and 400 mm.

In one exemplary embodiment the retainer 18 is an adhesive. The adhesive may be a mastic material securing the explosive 19 and/or the attenuator 16 to the second end of the tubular end piece 14.

In one exemplary embodiment the retainer 18 is a tube comprising a seat for the explosive 19. In one embodiment the retainer 18 and the attenuator 16 are integrated as a single component. The retainer 18 may be a tubular component wherein the second end of the tubular end piece 14 is pushed inside a first sleeve at a first end of the tubular component. The explosive 19 may be pushed inside a second sleeve at a second end of the tubular component.

In one embodiment the retainer 18 is a cold shrink tube. The cold shrink tube may comprise an internal support layer that may be pulled out when all components have been positioned inside the cold shrink tube. The cold shrink tube shrinks over the components at a room temperature, retaining them in place. In one embodiment the retainer 18 is a heat shrink tube. The heat shrink tube may be heated during the device assembly to shrink the tube. The hot boiler may further secure the connection.

In one embodiment the explosive 19, the retainer 18 and the attenuator 16 are integrated as one component. The detonator 17 may be pushed via the tubular end piece 14 into the explosive 19. The explosive 19 may comprise the attenuator portion and means for connecting to the tubular end piece 14, such as a sleeve.

In one embodiment the tubular end piece 14 and the retainer 18 form a tubular shape allowing the detonator 17 to travel from the first end of the tubular end piece 14 to be in contact with the explosive 19. FIG. 3 illustrates schematically one exemplary embodiment of the assembled device. Only the explosive-side end section of the lance tube 10 is visualized. The lance tube 10 may be between 0,5 m to 2 m in length. The lance tube 10 may comprise several continued segments. Length of each segment may be chosen according to practical portability. The lance tube 10 may be connected to cooling device, for example to pass cooling fluid into the lance tube to alleviate any heat-related problems during online deslagging. The cooling fluid may be inert gas or liquid such as water. Field tests conducted by the inventor have proven that simple shapes are more durable in the extreme conditions of the online deslagging - intense heat and explosions.

The detonator wire 11 travels through the lance tube 10 to the detonator 17, wherein the explosives may be blasted controllably from outside the boiler. In one embodiment the explosive 19 is an emulsion explosive. The device is in one example assembled outside the boiler before each blast. The detonator 17 is pushed into the emulsion explosive before entering the device into the boiler. The emulsion explosive blasts only when detonated, as it is configured to withstand the heat of the running boiler. The process of assembling the device is simple and the components are simple. Simplicity improves the safety as false assemblies are less likely. The attenuator 16 may comprise a shape at the first end that suits the rounded end of the tubular end piece 14. The components may be colour coded to increase the safety.

A device for online deslagging by blasting an explosive is disclosed. The device comprises a lance tube comprising a grip-side and an explosive-side end section; and means for connecting the explosive to the cleaning-side end section, wherein the explosive is connected to a detonator and a wire extending from the detonator to the grip-side. The means for connecting the explosive comprise: a tubular end piece having open ends, a first end being connectable to the explosive-side end section of the lance tube, wherein the detonator and/or the wire travels through the tubular end piece when connected to the device; the second end of the tubular end piece is configured to receive the retainer for the explosive; and the second end of the tubular end piece is rounded. In one embodiment an adhesive is the retainer configured to retain the explosive and the detonator at the second end of the tubular end piece. In one embodiment the retainer is an adhesive tape. In one embodiment the retainer is a tube comprising a seat for the explosive. In one embodiment the device comprises an attenuator between the second end of the tubular end piece and the explosive. In one embodiment the attenuator comprises an opening allowing the wire and/or the detonator to travel into the explosive through the attenuator. In one embodiment the attenuator is made of rubber. In one embodiment the attenuator is made of plastic. In one embodiment the attenuator is made of cardboard. In one embodiment the thickness of the attenuator between the second end of the tubular end piece and the explosive is between 10 mm and 40 mm. In one embodiment the explosive is an emulsion explosive. In one embodiment the retainer is a cold shrink tube. In one embodiment the retainer is a heat shrink tube. In one embodiment the tubular end piece and the retainer form a tubular shape allowing the detonator to travel from the first end of the tubular end piece to be in contact with the explosive.

Any range or device value given herein may be extended or altered without losing the effect sought.

Although at least a portion of the subject matter has been described in language specific to structural features and/or acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as examples of implementing the claims and other equivalent features and acts are intended to be within the scope of the claims.

It will be understood that the benefits and advantages described above may relate to one embodiment or may relate to several embodiments. The embodiments are not limited to those that solve any or all of the stated problems or those that have any or all of the stated benefits and advantages. It will further be understood that reference to ‘an’ item refers to one or more of those items.

The steps of the methods described herein may be carried out in any suitable order, or simultaneously where appropriate. Additionally, individual blocks may be deleted from any of the methods without departing from the spirit and scope of the subject matter described herein. Aspects of any of the examples described above may be combined with aspects of any of the other examples described to form further examples without losing the effect sought.

The term ‘comprising’ is used herein to mean including the method blocks or elements identified, but that such blocks or elements do not comprise an exclusive list and a method or apparatus may contain additional blocks or elements.

It will be understood that the above description is given by way of example only and that various modifications may be made by those skilled in the art. The above specification, examples and data provide a complete description of the structure and use of exemplary embodiments. Although various embodiments have been described above with a certain degree of particularity, or with reference to one or more individual embodiments, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the spirit or scope of this specification.

Claims

1. A device for online deslagging by blasting an explosive (19), comprising: a lance tube (10) comprising a grip-side and an explosive-side end section; and means for connecting the explosive (19) to the cleaning-side end section, wherein the explosive (19) is connected to a detonator (17) and a wire (11 ) extending from the detonator (17) to the grip-side, characterized in that the means for connecting the explosive (19) comprise: a tubular end piece (14) having open ends, a first end being connectable to the explosive-side end section of the lance tube (10), wherein the detonator (17) and/or the wire (11 ) travels through the tubular end piece (14) when connected to the device; the second end of the tubular end piece (14) is configured to receive the retainer (18) for the explosive (19); and the second end of the tubular end piece (14) is rounded.

2. A device according to claim ^characterized in that an adhesive is the retainer (18) configured to retain the explosive (19) and the detonator (17) at the second end of the tubular end piece (14).

3. A device according to claim 1 or claim 2, characterized in that the retainer (18) is an adhesive tape.

4. A device according to claim 1 or claim 2, characterized in that the retainer (18) is a tube comprising a seat for the explosive (19).

5. A device according to any of the claims 1 to 4, characterized by comprising an attenuator (16) between the second end of the tubular end piece (14) and the explosive (19).

6. A device according to claim 5, characterized in that the attenuator

(16) comprises an opening allowing the wire (11 ) and/or the detonator

(17) to travel into the explosive (19) through the attenuator (16).

7. A device according to claim 4 or claim 5, characterized in that the attenuator (16) is made of rubber.

8. A device according to claim 4 or claim 5, characterized in that the attenuator (16) is made of plastic.

9. A device according to claim 4 or claim 5, characterized in that the attenuator (16) is made of cardboard.

10. A device according to any of the claims 4 to 8, characterized in that the thickness of the attenuator (16) between the second end of the tubular end piece (14) and the explosive (19) is between 10 mm and 40 mm.

11.A device according to any of the claims 1 to 8, characterized in that the explosive (19) is an emulsion explosive.

12. A device according to any of the claims 1 to 11, characterized in that the retainer (18) is a cold shrink tube. 13. A device according to any of the claims 1 to 12, c h a r a c t e r i z e d in that the retainer (18) is a heat shrink tube.

14. A device according to any of the claims 1 to 13, characterized in that the tubular end piece (14) and the retainer (18) form a tubular shape allowing the detonator (17) to travel from the first end of the tubular end piece (14) to be in contact with the explosive (19).