WO2005045354A1

WO2005045354A1 - An explosive removal device and a method of a removing the lining of an equipment

Info

Publication number: WO2005045354A1
Application number: PCT/BR2003/000161
Authority: WO
Inventors: Guilherme QUINDERÉ ROMANO; Giancarlo Cantaluppi Silvestri De Freitas; Joel LIGIÉRO VARGAS, Jr.
Original assignee: Indústria De Material Bélico Do Brasil (Imbel); Abb Ltda.
Priority date: 2003-11-10
Filing date: 2003-11-10
Publication date: 2005-05-19
Also published as: AU2003275813A1; EP1690061A1

Abstract

An explosive removal device (10) is described, particularly for removing lining(12) and incrustation from an equipment (11), comprising at least one body (4) provided with at least one explosive chemical element (6), at least one detonating element (7) associated to the explosive chemical element (6) and at least one shock-absorbing element (5). In the preferred. embodiment herein disclosed, the explosive removal device (10) comprises at least one fixing means for fixation to the linIng (1, 2) associated to the body (4). It is also described a method of removing the lining of an industrial equipment, by means of use of the explosive removal device (10) herein disclosed.

Description

Title: "AN EXPLOSIVE REMOVAL DEVICE AND A METHOD OF REMOVING THE LINING OF AN EQUIPMENT"

The present invention relates to an explosive removal device, particularly for removing refractory concrete existing on an equipment, as well as a method of removing lining of an equipment, particularly refractory concrete. Description of the Prior Art There are various industrial pieces of equipment that has an internal refractory-concrete lining, which has the important property of signifi- cantly reducing the heat transfer from the inside of the equipment to the outer environment. In this way, it is used for lining furnaces and towers for processing oil and it derivatives (as for example a FCC converter) in refineries, for instance. These pieces of equipment, as a rule, have large dimensions and very high acquisition cost, and may easily reach hundreds of million dollars. So, the replacement thereof due to total loss is something that should be avoided at any cost. Taking the above-mentioned FCC converter as an example, it processes petroleum and its by-products, for produce gasoline, LPG (Lique- fied Petroleum Gas) and other derivatives. As already mentioned, the refractory concrete existing inside a FCC converter has the main function of decreasing the heat transfer to the environment. However, with the passage of time and the continuous use of the equipment, petroleum or another product processed therein is absorbed by the refractory concrete, which decreases its refractoriness. In addition, the layer of refractory concrete wears out with usage and becomes thinner. At the end of a determined period of functioning, the layer of refractory concrete no longer manages to prevent said heat transfer in an effec- tive manner. As a result, these pieces of equipment have a programmed maintenance routine that includes, in a determined interval of time, the re- moval of the layer of existing refractory concrete and replacement thereof. At present, the removal of this layer of refractory concrete is carried out with pneumatic small hammers, the successive impacts of which on the concrete cause cracks that culminates in breaking it, and thus one can remove it. However, this method is slow and unhealthy for those who work with such pneumatic hammers and who suffer high levels of vibration. The slowness, above all, is a great drawback, since the time during which the equipment remains inoperative generates a great loss of profits. With a view to eliminate these drawbacks and particularly to reduce the time it takes to remove the refractory concrete, a first solution was proposed and described in document GB 1549101, which discloses a method for removing the refractory lining form a furnace by using explosives. In this way, the time required for removing the layer of lining was reduced. However, this method has some peculiarities that, although it is functional with furnaces having thick metallic walls (30 mm or more), lined with refractory bricks, it could not be used with pieces of equipment such as FCC converters, the metallic walls of which have smaller thickness on the order of from 6 to 25 millimeters. The explosives used as mentioned in that document deform and damage the walls of the equipment, making it unfeasible to use the latter. Another solution, which is similar, is disclosed in document EP 0219061, which also discloses a method for removing the lining from furnaces. It should be noted that the linings of this solution are identical to those presented in the solution disclosed in the previous document, with the only difference that this document foresees a furnace lining molded with bores for positioning the explosives. Document US 3,951 ,065, in turn, discloses an explosive for removing ice from railway tunnels and similar underground cavities. Although it employs the same principle of functioning, the explosive device devised for this purpose is completely different from that created for removing the layer of refractory concrete from an industrial equipment having walls with reduced thickness. Therefore, until the present moment, nobody had developed an explosive device for removing refractory concrete or other linings from thin walls of industrial pieces of equipment, with safety and without damaging the equipment.

Objectives of the Invention The present invention has the main objective of providing an explosive removal device that enables one to remove refractory concrete or other linings from reduced-thickness walls of pieces of an equipment (partϊcu- larly an industrial equipment), efficiently, rapidly and safely, without causing any damage to the equipment. Also, a second objective of the present invention is to provide a method of removing lining from an equipment, which uses the explosive device invented now. Brief Description of the Invention The first objective of the present invention is achieved by means of an explosive removal device, particularly for removing lining and incrustation from an equipment, comprising at least one body provided with at least one explosive chemical element, at least one detonating element associated to the explosive chemical element and at least one shock-absorbing element. The second objective of the present invention is achieved by means of a method for removing a lining from an equipment, comprising the following steps: - (i) positioning at least one explosive removal device at a portion of the lining of the equipment; - (ii) fixing the explosive removal device to the lining portion; and - (iii) detonating the explosive removal device. The present invention has the advantages of providing an explosive device for removing refractory concrete from an equipment that expe- dites the charging and stemming activities and makes them easy to carry out. The use of an absorbing element offers protection to the equipment structure, since it prevents the shock waves from being transmitted to the sidewall of the equipment, thus preventing the occurrence of damages resultant from the detonation. Due to its reliability, the explosive removal device has been homologated by the companies that have the expensive industrial equipments. Further, the use of the present device increases the velocity of removing the refractory concrete, decreasing the time of turnaround of the equipment, thus reducing the loss of profits to a minimum. Brief Description of the Drawings The present invention will now be described in greater detail with reference to an embodiment represented in the drawings. The figures show: - Figure 1 is a cross-section view of the explosive removal device of the present invention; - Figure 2 is a cross-section of the bushing of the explosive device illustrated in figure 1 ; - Figure 3 is a cross-section of the screw used for fixing the ex- plosive illustrated in figure 1 ; - Figure 4 is a cross-section view of the cover of the cartridge body of the explosive assembly illustrated in figure 1 ; - Figure 5 is a schematic cross-section view of an industrial equipment containing a plurality of explosive devices as illustrated in figure 1 , without the actuating detonating cords; - Figure 6 is a schematic cross-section view of the industrial equipment containing a plurality of explosive devices as illustrated in figure 1 with the actuating detonating cords; and - Figure 7 is a across-section view of the explosive removal de- vice of the present invention during the step of installing it in a bore of the layer of refractory concrete of the equipment illustrated in figures 5 and 6. Detailed Description of the Figures According to a preferred embodiment and as can be seen in figure 1 , the explosive removal device 10 of the present invention is preferably designed for removing the lining and incrustation of an equipment 11 that will be explained later, and comprises at least one body 4 to which at least one explosive chemical element 6, a shock-absorbing element 5, at least one detonating element 7 and at least one fixing element for fixation to the lining 1,2 are associated. It should be initially noted that the preferred embodiment of the explosive removal device 10 is designed for removing the lining of refractory concrete 12 from an industrial equipment 11 , such as a furnace of the iron- and-steel industry or a FCC converter for processing petroleum and/or its derivatives. Evidently, however, the herein revealed explosive removal device 10 can be used to remove material and incrustation from every kind of industrial and non-industrial equipments, such as furnaces, tunnels, underground or building cavities, etc. Considering the industrial equipment 11 in question, it comprises a structure or sidewall 13, formed by a steel shell of a determined thickness, conventionally from 6 mm to 40 mm, although these values are a mere refer- ence and may vary in a considerable way. The structure 13 defines an inner cavity 14, in which the product is located, subjected to any processing, as for instance copper, aluminum, petroleum, liquefied petroleum gas (LPG), gasoline, etc. This product should be heated to high temperatures to be processed. In this sense, it is important to note that, whatever the equipment

11 is, it comprises a structure 13 and a cavity 14. Besides, the equipment 11 may comprises a structure 13 which does not configure a cavity, as a wall, for an example. In order to avoid the undesirable heat transfer from the interior of the cavity 14 to the outer environment through the structure 13, the latter comprises, on its inner surface (therefore, facing the inside of the cavity), a layer of refractory lining 12, preferably in the form of a refractory concrete. This material has good refractoriness properties, thermally insulating the inside of the structure 13. The layer of refractory concrete 12 is fixed to the structure 13 by means of its joining capacity and also, preferably, by means of anchoring clamps (not shown). However, as the equipment 11 is used, the refractory lining 12 wears out, basically due to two motives, namely: • the product to be processed may be absorbed by the concrete, which becomes soaked-up and begins to lose its re- fractoriness properties; • the product ends up dissolving the concrete by physical- chemical abrasion, decreasing the thickness of the lining layer and, as a result, the heat transfer begins to assume an undesirable and uneconomical proportion. In view of this situation, it is necessary to create a periodic preventive maintenance plan for this industrial equipment 11 , for the purpose of replacing the layer of refractory concrete 12, among other maintenance services. The explanation about the industrial equipment 11 and the situa- tions that demand the explosive removal device 10 of the present invention having been given, we will now describe it in detail. The body 4 has the main function of grouping all the other components of the explosive removal device 10 and enabling one to fix it to the layer of refractory concrete 12. Preferably, the body 4 is made from nylon and has a substantially cylindrical shape, defining an inner cavity 4', and is delimited by a first outer closed portion 41 and a second outer open portion 40 opposite the first one. The preferred dimensions of the body 4 are about 50 millimeters in height and 20 millimeters in diameter. Evidently, the body 4 may be made from any plastic or metallic material and assume various other dimensions and configurations, as for instance, it may have the first end 41 open and have other shapes than the cylindrical one, as long as it is functional. The second open portion 40 of the body 4 is associated to a cover 3, which evidently has to cooperate with it. In the preferred embodiment, the cover 3 is cylindrical in shape and is associated to the body 4 by gluing. However, the cover 3 may be associated to the body 4 in any other way, as for example by screwing. Still preferably, the cover 3 is made from nylon and has a through passageway 3' to enable one to position the detonating element 7, which will be better defined later. One may further foresee an explosive removal device without the cover 3. Inside the inner cavity 4' of the body 4, a shock-absorbing element 5 and a chemical explosive element 6 are foreseen. The shock-absorbing element 5 has the function of absorbing explosion energy from the explosive element 6 in the region where it is lo- cated, with a view to protect the sidewall 13 of the industrial equipment 11 , as will be mentioned later. Preferably, it comprises a plurality of intercalated steel blades, polymeric elements or any other functional material. Still preferably, the absorber 5 is positioned adjacent the first closed end 41 of the body 4. The chemical explosive element 6, in turn, is responsible for the functioning of the explosive removal device 10. It may be constituted by any substance or composite that is functional and efficient in accordance with the required design parameters. The explosive element 6 is positioned adjacent the absorber 5. Preferably, the present invention uses the explosives as described in the table below.

Alternatively, one can uses other functional chemical explosive elements 6 according to the convenience, and it is even possible to use a moisture of one of more elements. Whatever the chemical explosive 6 element is, it must have a detonation speed range between 2.000 meters in one second (m/s) and 8.000 m/s, and more preferably a range between 2.500 m/s and 7.000 m/s. The range detonation speed of the used chemical explosive element 6 are considered high, if compared to the detonation speed of other explosives mainly used, since a high detonation speed is necessary to remove the refractory lining 12 of the equipment 11 without damaging its structure 13. Preferably, but not compulsorily, the absorber 5 and the explosive element 6 occupy each about 50% of the volume of the inner cavity 4' of the body 4. The fixing means for fixation to the lining 1 ,2 accounts for fixing the body 4 close to the layer of refractory concrete 12, which will be detonated, and preferably comprises at least one screw 1 and at least one expandable bushing 2. Its principle of functioning is based on the fact that the screw 1 , when driven into the bushing 2, provides an increase of the outer diameter, so that the bushing remains locked to the bore in which the removal explosive 10 is installed. Alternatively, the screw may be driven into the cover 3 or into the body 4. In this way, the whole energy released in the detonation is directed to fragment the layer of refractory concrete 12. One may therefore say that the bushing provides stemming of the explosive removal device 10 inside the bore of the layer 12. In the preferred embodiment, the screw 1 is made from aluminum or steel and is substantially conical or in the form of a truncated cone, especially at its thread. Still preferably, the screw 1 has a through bore 1', which enables one to position the detonating element 7. The screw head is preferably hexagonal. Evidently, both the material and the shape of the screw 1 may vary, provided that it continues to be functional. The bushing 2 is preferably made from polyurethane, is substantially cylindrical in shape and has a threaded through-bore that cooperates with the screw and allows the detonating element 7 to pass. In addition, the bushing 2 has grooves for radial expansion with a 30-degree angle and is serrated, which increases the friction upon its deformation with the increase of the diameter. However, it is clear that the specifications and particularities of the bushing 2 may vary, as long as they provide a correct functioning. In the preferred embodiment of the explosive removal device 10, the bushing 2 is glued onto the cover 3, but evidently this is not a compulsory characteristic. The bushing 2 may be loose, for instance, confining the body 4 inside the bore made in the layer of refractory concrete 12. Moreover, it should be pointed out that the fixing means for fixation to the lining 1 ,2 may comprise other components whatever than a screw and a bushing, provided that these other components enable the correct fixation of the body 4 to the layer 12. Finally, the explosive removal device 10 comprises a detonating element 7, which may have any configuration already available or known, as for example, a detonating cord, since this is not the objective of the present invention. Its function is only to detonate the chemical explosive 6, actuating the explosive removal device 10. The detonating cord 7 may further be replaced by any other detonating element, such as explosive loads actuated via radio, for instance. For the preferred embodiment of the explosive removal device 10, its assembly comprises the following sequence: First, one accommodates the absorbing element at the first closed end 41 of the body 4, occupying about 50% of its volume. Then, one charges the chemical explosive element 6 on the shock absorber 5, occupying the remaining 50% of the body 4. After this loading is completed, one places the detonating cord 7, closed the cartridge body 4 with the cartridge cover 3 by gluing or by interference. Finally, one glues the confinement bushing 2 onto the cartridge cover 3. In this way, the device is ready to be charged into the bore of the layer of refractory concrete 12. It should be reminded that the detonating cord 7 is long and projects out of the explosive removal device 10 through-bores/openings existing in the cover 3, bushing 2 and screw 1. Evidently, the sequence of assembling the explosive device 10 may be a little different depending upon the possible configurative variations described herein. The explosive removal device 10 having been described in all its details, we will now describe the method for removing the lining from an industrial equipment 11 , which comprises the installation of at least one device 10 in the layer of refractory concrete 12 of an industrial equipment and its detonation. Essentially, the method for removing the lining from an industrial equipment comprises the following steps: - (i) positioning at least one explosive removal device 10 as defined in the claims of this invention in a portion of the lining 12 of the industrial equipment 11 ; - (ii) fixing the explosive removal device 10 at the lining portion

12; and - (iii) detonating the explosive removal device 10. Initially, before the step (i), it is necessary to make a bore in the layer of refractory concrete 12 to enable one to position the explosive re- moval device 10. Preferably, the bore should have a shape similar to the device 10 and dimensions just a little bigger, for allowance of expansion of the bushing 2 or so that it can be steadily fixed to the lining 12. Evidently, this may vary depending upon the characteristics of the components of the fixing means, in case they are not a screw and a bushing. Preferably, it is interesting to realize a plurality of bores in a circular pattern, due to the advantages resulting of good energy dissipation in the lining, particularly in the thin walls of the equipment 11. This situation increase the efficiency of the detonation step (iii). It is also important to note that the bores are made with the par- ticular tools to realize the purpose. As an example, one may use tools to make bores with special shape, with highly controlled depth, etc.). The properties of the bores may vary depending upon the particular situation (kind of equipment, configuration of the lining 12, kind of chemical explosives, etc.). Alternatively, if the layer of refractory concrete already has pre- molded bores, this initial perforating step is not necessary. The step (ii) of positioning the explosive removal device 10 cor- responds to the manipulation of the bushing 2 and the screw 1 (or the like) of the means for fixation to the lining 1 , 2, enabling its correct fixation to the bore. Still more particularly, it corresponds to the driving of the screw 1 against the bushing 2. Considering the step (ii), it is important to note that it is an inven- tion itself, since the use of a screw 1 and bushing 2 to fix an explosive removal device 10 in a wall is new and inventive. Conventionally, the removal devices are fixed to^" the walls by means of plastic resins, plaster stone, concrete, polymeric foamy, etc. The use of bushing and screw enables a better, safer, easier and faster fixation of the explosive removal devices in compari- son to the above mentioned fixation means. It is should be further noted that, alternatively, the step (ii) is preceded by a step of installing an external detonator at the detonating element 7, by using an adhesive tape, a connector or other means. The detonator may be electric, non-electric, electronic or any other type that is necessary or desirable. Finally, after detonation of the explosive removal device 10, it may be necessary to remove the rests of the lining of the detonated refractory concrete that have not detached form the structure 13 of the industrial equipment 11 , when the process described here further comprises a step (iv) of removing this detonated lining by hand. For detonation of the lining of a refractory concrete 12 of an equipment 11, however, many explosive removal devices 10 are necessary, which require a plurality of bores in the lining 12, spaced apart in accordance with design calculation, which may vary from case to case. Therefore, a number of bores are made in the refractory concrete

12, if they have not been provided, until the surface of the metallic place is reached. A unite of the explosive removal device 10 corresponding to the step (i) is introduced into each bore. After this, one fixes the explosive device inside the bores, which corresponds to the step (ii). Preferably, one effects this fixation by employing electric or pneumatic screw machine that, with an adequate torque, locks the device through the screw 1. The bushing 2 ex- pands and confines the device 10. Each bore being charged with the explosive removal device 10 stemmed, one performs the normal sequence of activities, according to the method of removing refractory concrete from an industrial equipment by using explosives, which corresponds to the step (iii) of detonating the explosive. This detonation may be carried out by any known means, such as non-electric detonators associated to the detonating cords 7, detonation via radio, etc. The detonation must be absolutely reliable, in order to avoid failures that may impair the work or else damage the equipment 11. As mentioned, the bores in the refractory lining are perforated until the metallic surface of the structure 13 of the equipment is reached. This ensures that the whole refractory concrete will be weakened, but in return exposes the structure 13, which might be damaged under the strength of the detonation of the explosives. This fact is particularly serious in the case of equipments such as the FCC converters, the structure of which has walls with quite reduced thickness, ranging from 6 to 25 millimeters. Therefore, the existence of the absorbing element 5 is imperious, which, in conjunction with the explosive element 6 used (according to design calculations, they vary from case to case depending upon the industrial equipment and the materials employed, evidently), enables the explosive removal device 10 to have sufficient power to fragment the layer of refractory concrete 12 effectively and reliable, at the same time as the force of the detonation that might damage the structure 13 are correctly absorbed by the absorber 5. Evidently, the detonation speed of the used chemical explosive element 6 must be defined conjunctly with the absorbing element, in order to guarantee the performance of the explosive removal device 10. In this way, the explosive removal device 10 for removing refrac- tory concrete 12 expedites the activities of charging and stemming and makes them easy to carry out, and the use of the absorbing element 5 provides greater protection for the metallic structure 13 of the industrial equipment. In this regard, it should be pointed out that the present explosive re- moval device 10 has exhibited absolute reliability of functioning, having been homologated by companies that have the expensive industrial equipments 11. Although it has been commented that the refractory material is concrete, it is evident that one can remove incrustations or any other material that may have the same function and also is located in the structure 13 of an equipment 11. ^" A preferred embodiment having been described, one should understand that the scope of the present invention embraces other possible variations, being limited only by the contents of the accompanying claims, which include the possible equivalents.

Claims

CLAIMS 1. An explosive removal device, particularly for removing lining (12) and incrustation from an equipment (11), characterized in that it com- prises at least one body (4) provided with at least one explosive chemical element (6), at least one detonating element (7) associated to the explosive chemical element (6) and at least one shock-absorbing element (5). 2. An explosive removal device according to claim 1 , characterized in that it comprises at least one fixing means for fixation to the lining (1 ,

2) associated to the body (4).

3. An explosive removal device according to claim 2, characterized in that the fixing means for fixation to the lining (1 ,2) comprises an expansive bushing (2) and a screw (1 ).

4. An explosive removal device according to claim 3, character- ized in that the bushing (2) has a through-bore inside it that cooperates with the screw (1).

5. An explosive removal device according to claim 4, characterized in that the screw (1) is substantially conical.

6. An explosive removal device according to claim 5, character- ized in that the screw (1 ) has a through-bore (1 ')•

7. An explosive removal device according to claim 6, characterized in that the screw (1 ) is drivable into the through-bore of the bushing (2).

8. An explosive removal device according to claim 7, characterized in that the body (4) has a cover (3), to which the bushing (2) is fixed.

9. An explosive removal device according to claim 8, characterized in that the cover (3) is glued to the body (4).

10. An explosive removal device according to claim 8, characterized in that the cover (3) is screwed into the body (4).

11. An explosive removal device according to claim 8, character- ized in that the cover (3) has a through opening (3').

12. An explosive removal device according to claim 11, characterized in that the screw (1) is drivable into the body (4).

13. An explosive removal device according to claim 1, characterized in that the body (4) is substantially cylindrical and defines an inner cavity

(4').

14. An explosive removal device according to claim 13, charac- terized in that the shock-absorbing element (5) is located in the inner cavity

(4').

15. An explosive removal device according to claim 14, characterized in that the energy-absorbing element (5) comprises a plurality of intercalated steel blades.

16. An explosive removal device according to claim 1 , characterizing in that the explosive chemical element (6) has a detonation speed range between 2.000 (m/s) and 8.000 m/s.

17. An explosive removal device according to claim 16, characterizing in that the explosive chemical element (6) has a detonation speed range preferably between 2.500 (m/s) and 7.000 m/s.

18. An explosive removal device according to claim 17, characterizing in that the explosive chemical element (6) is nitroglycerine.

19. An explosive removal device according to claim 17, characterizing in that the explosive chemical element (6) is Plastex.

20. An explosive removal device according to claim 17, characterizing in that the explosive chemical element (6) is Trotyl.

21. An explosive removal device according to claim 1 , characterized by comprising a detonating element (7) in the form of a detonating cord.

22. A method for removing a lining from an equipment, character- ized in that it comprises the following steps: . - (i) positioning at least one explosive removal device (10) at a portion of the lining (12) of the equipment (11 ); - (ii) fixing the explosive removal device (10) to the lining portion (12); and - (iii) detonating the explosive removal device (10).

23. A method according to claim 22, characterized in that the step (i) is preceded by a step of boring the lining portion (12), to allow the explosive removal device (10) to be positioned.

24. A method according to claim 23, characterizing in that the step of boring comprises to realize a plurality of bores in a circular pattern.

25. A method according to claim 24, characterizing in that the bores are made with the particular tools to realize the purpose.

26. A method according to claim 22, characterized in that the step (ii) corresponds to the manipulation of the fixing means (1 , 2) for fixation to the lining (12).

27. A method according to claim 26, characterized in that the manipulation of the fixing means for fixation to the lining (1 , 2) corresponds to the driving of the screw (1 ) against the bushing (2).

28. A method according to claim 22, characterized in that the step (iii) is preceded by a step of installing an external detonator on the detonating element (7), by using an adhesive tape, a connector or other means.

29. A method according to any one of claims 12 - 28, characterized in that it further comprises a step (iv) of removing the detonated lining by hand.