NL2030105B1

NL2030105B1 - Combustion oven heat exchanger cleaner

Info

Publication number: NL2030105B1
Application number: NL2030105A
Authority: NL
Inventors: Cornelis Den Hollander Aart
Original assignee: Derc Waterjetting B V
Priority date: 2021-12-10
Filing date: 2021-12-10
Publication date: 2023-06-27
Also published as: WO2023105070A1

Abstract

A system for cleaning an object, in particular the outside of combustion oven heat exchanger tubes (42). The cleaning system (2) comprises a cleaning device (4) having one or more nozzles (32, 34) configured forjetting a fluid. The cleaning device is coupled to a carrier arm (6), and the cleaning device is configured to be moved linearly in the longitudinal direction of the carrier arm (6), rotated in a first rotation direction around a first rotation axis (R1) parallel to the longitudinal axis (L) of the carrier arm (6), and rotated in a second rotation direction around a second rotation axis (R2) perpendicular to the first rotation axis (R1).

Description

P35198NLOO/TRE

Title: Combustion oven heat exchanger cleaner

FIELD OF THE INVENTION

The present invention relates to a system for cleaning an object, in particular combustion oven heat exchanger tubes with a cleaning device which is configured to be rotated and linearly moved with respect to the object to be cleaned.

BACKGROUND OF THE INVENTION

Heat exchangers are frequently used in industry for cooling or heating a fluid flow, such as to cool down the flue gasses generated by the combustion of fossil fuels, like coal, natural gas and oil to generate energy . Typically these combustion oven heat exchangers comprise multiple stacks of parallel tubes arranged in a matrix, and said stacks are separated by aisles. The hot flue gas from the combustion oven passes over the tubes of the heat exchanger wherein a cooling fluid flows, thereby cooling down the flue gas. During cooling of the gasses, dirt e.g. in the form of non-combustible components and solid combustion products, such as soot, accumulate on the outside of the tubes. Accumulation of this dirt decreases the heat exchanging efficiency. Consequently, to prevent efficiency loss, the tubes need to be cleaned regularly. Cleaning the tubes is often done manually by a person inside the combustion oven heat exchanger, with said person holding a hose and cleaning the tubes by abrasive blasting. This person is standing on a scaffold that is built in the heat exchanger during shut down and that is used for cleaning, maintenance and safety checks.

Manual cleaning of the combustion oven heat exchanger tubes by abrasive blasting with e.g. sand has multiple disadvantages, including high personnel costs, but it is also dangerous for human safety due to the hazardous environment inside the combustion oven heat exchanger and the blasting conditions: if sand or other substances containing free silica are used, anyone exposed to the dust generated by blasting the sand could develop silicosis.

Moreover, during the blasting operation, abrasive material rebounds from the surface of the tube with a high velocity. Consequently, the operator must be given special protective clothing such as gloves, apron and leggings. A helmet supplied with fresh air at a positive pressure is also necessary to protect the blaster from both flying particles and harmful dust. Thus, many measures must be taken before and during a cleaning operation, which dramatically decreases the efficiency of the cleaning process, and also increases the operation costs.

In the art, multiple cleaning methods and/or systems are known to replace manual cleaning of combustion oven heat exchanger tubes. A first, and coarse, method is to remove dirt of the combustion oven heat exchanger tubes by vibrations, e.g. by bringing an explosive into the heat exchanger, which causes a shockwave upon detonation. A large part of the dirt can be removed this way, even during operation of the heat exchanger, but there will always be some dirt left behind. Thus, for maintaining efficiency, the leftover dirt on the tubes still needs to be removed regularly, such as once or twice a year.

US 2830407 discloses a system for conveying a pressure-fluid borne stream of pellets, comprising an air conveyer, connected to a source of fluid under pressure, and a conduit means for feeding pellets into the pressure fluid stream. Accumulated deposits on the tubes of the heat exchanger are cleaned by projecting relatively hard pellets in between, along and against the tube surfaces. The blower tube through which the pellets are delivered is extending from a position outside of the heat exchanger into the heat exchanger by bending heat exchanger tubes to form a passage. The blower tube is configured to be moved linearly in and out of the heat exchanger through the passage. The end of the blower tube has a nozzle arrangement, such as two opposite nozzles, and the blower tube can fully rotate around its axis.

The system for sandblasting as described by US 2830407 requires the blower tube to be positioned in between the tubes of the combustion oven heat exchanger by inserting the blower tube through a passage. To form this passage, the heat exchanger tubes need to bend away from each other in order for the blower tube to be inserted. This insertion by bending away the tubes has multiple disadvantages, such as material fatigue and risk of buckling of the heat exchanger tubes, as heat exchanger tubes often have relatively thin walls to reduce the heat flow resistance as to make the transfer of heat as efficient as possible.

WO2019058031 discloses an industrial boiler and a method for cleaning heat transfer surfaces of the industrial boiler by blasting dry particle-form metal slag during operation of the boiler. The metal slag particles are blasted on the surface by a blasting pipe. The blasting pipe comprises a nozzle which is capable of blowing the slag particles sideways into at least two opposite angles with respect to the axial direction of the blasting pipe. The mechanism of insertion of the blasting pipe is similar to that of the blowing tube of US2830407: the blasting pipe is extending from a position outside of the boiler, and said blasting pipe needs to be inserted into the boiler with a linear motion. The main difference between the two systems, is that in the apparatus disclosed by WO2019058031 no tubes need to be bend, but instead a special boiler is required as disclosed in the application. The boiler comprises a wall with a heat resistant collar through which the blasting unit is inserted. Using this construction in already existing heat exchanger is therefore not possible.

BRIEF DESCRIPTION OF THE INVENTION

The present invention aims to overcome one or more of the above disadvantages at least partly or to provide a suitable alternative.

In particular the present invention aims at providing a system for cleaning combustion oven heat exchanger tubes which is semi-automated.

It is another object of the invention to improve the safety conditions during combustion oven heat exchanger tube cleaning.

It is a further object of the invention to provide a system for cleaning combustion oven heat exchanger tubes more efficiently.

In a first aspect, the present invention provides a system for cleaning an object, in particular the outside of combustion oven heat exchanger tubes, comprising a cleaning device having one or more nozzles configured for jetting a fluid coupled to a carrier arm, wherein the cleaning device is configured to be moved linearly in the longitudinal direction of the carrier arm, rotated in a first rotation direction around a first rotation axis parallel to the longitudinal axis of the carrier arm, and rotated in a second rotation direction around a second rotation axis perpendicular to the first rotation axis.

The system for cleaning an object according to the invention can be used to clean combustion oven heat exchanger tubes during shut down of the combustion oven. These combustion oven heat exchangers typically comprise multiple stacks of tubes wherein the tubes are positioned in a stack according to a (regular) pattern, such as a matrix of rows and columns. The tubes are arranged spaced apart from one another leaving free a gap between them. The stacks themselves are separated by aisles. The cleaning system according to the present invention can be placed in these aisles. For cleaning the tubes, the cleaning system comprises a cleaning device, which in turn comprises one or multiple nozzles through which a fluid, such as water or air, is jetted onto the tubes to remove the dirt. The cleaning system according to the invention further comprises a carrier arm for carrying the cleaning device.

The carrier arm preferably has a length such that the cleaning device can be aligned with a stack of tubes in the combustion oven heat exchanger and such that its length covers a plurality of adjacent tubes along one side (row/column) of the stack of tubes. The carrier arm can also be linkable to adjacent carrier arms such that the cleaning system covers the entire length or width of a combustion oven heat exchanger.

When the system is used for cleaning an object, in particular for cleaning combustion oven heat exchanger tubes, the carrier arm is positioned in front of the front row or column of the tubes. Typically, the tubes are placed vertically in the heat exchanger, and the carrier arm is placed horizontally in the aisle between stacks of tubes. During jetting of the cleaning fluid, the cleaning device is operated to horizontally move along the adjacent tubes. The cleaning device can be rotated in two directions: vertically in a first rotation direction and horizontally in a second rotation direction. Upon linear movement and/or rotation in the second rotation direction, the fluid is jetted through the gaps between adjacent tubes, assuring that all tubes, including the rear tubes of the stack, are hit with the fluid. Upon rotation about the second rotation axis, the jets of fluid project not only on a frontal part of the tubes, as it was the case in prior art systems, i.e. projecting on a frontal half of the circumference of the tubes. Instead, the jets of fluid can also project beyond this frontal part and/or can reach tubes that lie deeper into the stack. It is thus not necessary to insert the nozzles of the cleaning device into the stack of tubes. Upon rotation about the first rotation axis parallel to the longitudinal axis of the carrier arm the jets of fluid hit a larger vertical part of the tubes, which increases the cleaning area per stroke. Thus, the movements of the cleaning device mimics the movements of a person that would otherwise be cleaning the tubes manually: the person would horizontally and vertically move a hose while jetting, to jet the fluid in between rows of combustion oven heat exchanger tubes and to clean the largest possible area before moving on. The cleaning operation can be carried out while cleaning fluid is jetted continuously. The cleaning device can also be operated intermittently.

Typically, the cleaning device comprises a connecting part with which the cleaning device is connected to the carrier arm. In an embodiment of the invention, the connecting part is configured to be moved linearly in the longitudinal direction of the carrier arm and therewith the cleaning device is allowed to be displaced linearly. The linear motion may be intermittent as the cleaning device moves back and forth on the carrier arm. The linear movement can be driven by e.g. a first drive means which is positioned on the connecting part of the cleaning device. The first drive means can also be positioned elsewhere in the cleaning system.

In a preferred embodiment of the invention, the first drive means comprises a friction drive or an engagement drive, such as a rack and pinion or similar system. The carrier arm may for instance be a bar provided with a plurality of openings thereby forming the rack, wherein a driven pinion engages for moving the connecting part of the cleaning device.

Although it is preferred in view of space considerations to linearly move the cleaning device with respect to the carrier arm, it is also possible to keep the cleaning device at a fixed place on the carrier arm while moving the entire carrier arm with respect to the object to be cleaned.

In a preferred embodiment of the invention, the cleaning device comprises two nozzles that are positioned in opposite directions. Advantageously, with two nozzles in opposite directions, the tubes on both sides of the cleaning device and thus the respective aisle can be hit by the fluid, which increases the efficiency of the cleaning process. It is also possible to increase the number of nozzles to further increase the cleaning efficiency.

In a further preferred embodiment of the invention, the cleaning device is configured to jet solid particles from the nozzles. The fluid jetted from the nozzles typically comprises 5 compressed air carrying the solid particles. These solid particles can include e.g. highly abrasive particles, such as sand or metal slag, or moderately abrasive particles, such as glass beads. Barely abrasive blasting materials, such as dry-ice, could also be jetted through the nozzles. In the present invention, the use of highly abrasive particles is preferred, as these have the highest impact and are therefore the best means for removing all the dirt.

Because of the friction between the finely divided particles of sand and the nozzles, discharges of static electricity occasionally take place. It is therefore preferred to earth the cleaning system.

The carrier arm is preferably mounted in one or more attachment means, such as two attachment means at the ends of the carrier arm. Although it is possible that the attachment means, and thereby the carrier arm, can be attached to any suitable member associated with or located near the object to be cleaned, such as the combustion oven heat exchanger tubes, it is preferred that the attachment means are arranged to be attached to a separate supporting system, such as a scaffold. Typically, scaffolds are built in the heat exchanger during shutdown to perform safety checks of the tubes, such as to check the tube thickness.

When using these already existing scaffolds, further support members are not required for operating the system.

The attachment means may be coupled to the scaffold, or any other supporting system, for instance using a clamp for clamping onto the scaffold, but it is preferred if the attachment means are provided with a coupling plate with recesses with which the attachment means can be coupled to the scaffold, e.g. using crossheads or bolts.

The attachment means are preferably slidably arranged on the carrier arm.

Advantageously, the slidably arranged attachment means ensure that the width between two attachment means can be made compatible to the width of any support member

The cleaning device is configured to be rotated in a first rotation direction around a first rotation axis parallel to the carrier arm. In a preferred embodiment of the invention, the carrier arm is configured to be rotated around its longitudinal axis, thereby also rotating the cleaning device which is positioned on the carrier arm. To achieve the rotation, advantageously the carrier arm is rotatably mounted in the attachment means, e.g. using ring bearings. Alternatively, the connecting part of the cleaning device could be rotatably mounted on the carrier arm, to rotate the connecting part with respect to the carrier arm around a rotation axis parallel to the carrier arm.

It is preferred that the carrier arm and therewith the cleaning device with the nozzles, is configured to be rotated intermittently between a range of angles, for example from -45 — 45°, for example from -35 - 35°, such as from -30 - 30°, wherein 0° is defined as the direction towards the object to be cleaned in a plane perpendicular to the main direction of the object, in particular the longitudinal direction of the tubes. Full rotation of the nozzles is unnecessary in the case of cleaning combustion oven heat exchanger tubes: as mentioned before, the combustion oven heat exchanger comprises multiple stacks of parallel tubes arranged in a matrix. The stacks of tubes are separated by aisles, and the carrier arm is placed in the aisle, in between stacks of tubes. As opposed to the prior art systems, the nozzles of the cleaning device are not configured to be inserted in the stacks of tubes, but instead the nozzles remain positioned in front of the tubes, in the aisles. Consequently, if the nozzles were to be fully rotated, a substantial amount of fluid would be jetted in the direction of the aisles, where no tubes are present. Jetting fluid in directions where there are no objects to be cleaned decreases the efficiency of the cleaning process and increases the costs due to the redundant material.

The first rotating movement can be driven by e.g. a second drive means positioned in one of the one or more attachment means.

The cleaning device is also configured to be rotated in a second rotation direction around a second rotation axis perpendicular to the first rotation axis. In a preferred embodiment of the invention, the second rotation movement is achieved by configuring the nozzles of the cleaning device to be rotated with respect to the connecting part, e.g. using a nozzle holder that is rotatably mounted to the connecting part. As with the first rotation movement, it is preferred that the nozzles are configured to be rotated intermittently between a range of angles, e.g. from -45 - 45°, for example from -30 - 30°, such as from -10 - 10°, wherein 0° is defined as the direction towards the object to be cleaned in a plane perpendicular to the main direction of the object, in particular the longitudinal direction of the tubes. The same reasoning applies for intermittently rotating the second rotation movement as mentioned above: full rotation around the rotation axis causes fluid to be jetted into the aisles, thereby decreasing the cleaning efficiency and increasing costs due to redundant material.

The second rotating movement can be driven by e.g. a third drive means positioned on the connecting part.

In an embodiment of the invention, the cleaning system further comprises a supporting system perpendicular to the longitudinal axis of the carrier arm, wherein the attachment means are attached to the supporting system, and the attachment means are configured to be moved linearly on the supporting system. In the case of a horizontally placed carrier arm, the cleaning system would thus comprise a vertical supporting system on which the attachment units can be moved vertically. The cleaning device would thus be able to also clean the full height of the vertically placed tubes and could therefore replace the first rotation movement. To move the attachment units, the supporting system could comprise for example a similar rack and pinion system as mentioned above.

The drive means for driving the linear and rotation movements can be chosen from known devices, such as electrical or pneumatic motor systems. Typically, pneumatic motor systems are used.

In a further preferred embodiment of the invention, the system comprises a controller for remotely controlling at least the drive means and the nozzles of the cleaning device. The controller is coupled to the drive means and is provided with suitable control means for controlling the operation of the drive means. Preferably the controller is coupled to the drive means using pneumatic lines. The drive means are thus remotely operable, such that the operator can operate the cleaning device from outside of the heat exchanger.

In a further embodiment of the invention, the cleaning device comprises sensors configured to emit a sensor signal representative for the position of an object, such as the combustion oven heat exchanger tubes. This allows to determine the position of the cleaning device in relation to the tubes. In a further embodiment of the invention, these sensor signals can be used to control the drive means and/or the cleaning device.

In a further preferred embodiment of the invention, the nozzles of the cleaning device are fluidly connected to a container containing the fluid that is to be jetted. This can be achieved by e.g. using connection tubes connecting the nozzles and the container. If the cleaning device would rotate completely around its axis, the connection tubes would get entangled. Advantageously, the intermittent back and forth rotation and linear movement prevents entanglement of the connection tubes.

In a further aspect the invention also resides in a method for cleaning an object, in particular combustion oven heat exchanger tubes, using the cleaning system according to the invention, comprising the step of jetting a cleaning agent from the one or more nozzles while the cleaning device is moved linearly in the longitudinal direction of the carrier arm, and/or rotated in a first rotation direction around a first rotating axis parallel to the longitudinal axis of the carrier arm, and/or rotated in a second rotation direction with a second rotation axis perpendicular to the first rotation axis.

As mentioned before, the cleaning system is typically placed in the aisles of a combustion oven heat exchanger, such that the length of the horizontally placed carrier arm corresponds to the width of a stack of vertically placed tubes. This allows the cleaning device to move along all the tubes. The cleaning device could then simultaneously or subsequently perform a rotational movement. The cleaning device can for example move linearly to a new position in front of two rows of tubes, after which the cleaning device can be rotated in two directions to clean all tubes in the columns of the two rows of tubes in front of which the cleaning device is positioned. It is also possible, for example, to set the rotation angles per stroke in which the device moves on the carrier arm.

During the cleaning process, the cleaning device intermittently rotates back and forth in a range of angles, for example from -45 — 45°, for example from -30 - 30°, such as from -10 - 10° horizontally and from -45 — 45°, for example from -35 - 35°, such as from -30 - 30° vertically. With the horizontal rotation, the fluid is jetted through the rows of tubes, which ensures that every tube is hit with the fluid, including the rear tubes of the stack, without requiring the nozzles to be inserted into the stacks of tubes.

Because the fluid is jetted from the nozzles of the cleaning device at an angle onto the tubes, there will be an overlap of the nozzles' working areas at the rear tubes as the cleaning device is displaced vertically. Since the jet of fluid, when it reaches the rear of the tube is also less powerful, an overlap of the working areas will ensure that the rear tubes are also cleaned properly.

As the cleaning system is not able to clean the full circumference of the tube, it is preferred to place a second cleaning system on the other side of the stack, to clean the remaining part of the tubes which the first cleaning system cannot reach.

In a further embodiment of the invention, the method for cleaning an object, in particular combustion oven heat exchanger tubes comprises the attachment means to be moved linearly on the supporting system in a direction perpendicular to the longitudinal axis of the carrier arm. In the example as mentioned above, in which the carrier arm is horizontally placed in between stacks of vertically placed tubes, the supporting system would e.g. be placed vertically, so the carrier can be moved vertically for the cleaning device to clean the full height of the tubes.

In a preferred embodiment of the invention, at least the drive means and/or the cleaning device are remotely controlled by an operator.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is further illustrated by the attached figures, wherein:

Fig. 1 shows an embodiment of a system for cleaning an object according to the invention;

Fig. 2 shows a top view of the embodiment of Fig. 1 when positioned in a combustion oven heat exchanger,

Fig. 3 shows a cross-section of the cleaning device according the embodiment of Fig. 1.

DETAILED DESCRIPTION OF THE DRAWINGS

Fig. 1 shows an embodiment of a system for cleaning an object, in particular combustion oven heat exchanger tubes, according to the invention, which in its entirety is denoted by reference number 2. The system 2 comprises a cleaning device 4 which is connected to a carrier arm 6 by a connecting part 8. The connecting part 8 surrounds the carrier arm 6, and comprises a first drive means 12. The first drive means 12 is arranged to drive the linear movement of the connecting part 8 in the longitudinal direction of the carrier arm 6, said drive means 12 comprising a rack and pinion system, wherein the carrier arm 6 comprises holes for the rack, and the drive means comprises a pinion which engages the rack holes to enable a linear motion. The pinion is connected to a pneumatic motor via suitable transmissions. Actuation of the pneumatic motor will thus rotate the pinion, thereby translating the connecting part 8 on the carrier arm 6 .

The carrier arm 6 is rotatably mounted in two attachment means 16, 18, arranged near the end of the carrier arm 6. The attachment means 16, 18 comprise coupling plates 20, 21 on which ring bearings 22, 24 are mounted. The ring bearings 22, 24 have holes through which the carrier arm 6 extend. Thus the carrier arm 6 is rotatably mounted with respect to the coupling plates 20, 21. The attachment means 16, 18 have projections 26, 27, 28, 29 with which the attachment means 16, 18 can be mounted on a supporting system, such as a scaffold. The attachment means 16, 18 are slidably arranged on the carrier arm 8 to increase or decrease the width between the attachment means 16, 18, making the cleaning system 2 compatible to the width of any support system or scaffold.

One of the attachment means 16 further comprises a second drive means 30 to drive the rotation of the carrier arm 6 around its longitudinal axis L, which is shown as the dashed line, by rotating the ring bearings 22, 24 in which the carrier arm 6 is mounted. Consequently, the cleaning device 4 is also rotated around a rotation axis R1 which is equal to the longitudinal axis L of the carrier arm 6.

The cleaning device 4 further comprises two nozzles 32, 34 which are positioned in opposite directions and a sensor 35 for detecting objects. Fluid for cleaning is jetted through these nozzles 32, 34. A third drive means 36 is provided in the cleaning device 4 to drive the rotation of the nozzles 32, 34 around a rotation axis R2 perpendicular to the longitudinal axis

L of the carrier arm 6. The drive means can comprise e.g. a gear drive or a belt drive. The nozzles 32, 34 can be fluidly connected with tubes 38, 40 to a container 41 that holds the fluid whichis to be jetted, e.g. pressurized air with solid particles, such as sand.

Fig 2a. shows a top view of the embodiment of Fig.1. when placed in a combustion oven heat exchanger. A cross-sectional view of vertically placed tubes 42 of the heat exchanger is shown. The tubes 42 are arranged in matrices, and the two stacks of tubes that are shown are separated by an aisle 44 in which the carrier arm 6 is placed horizontally. The cleaning device 4 with the two nozzles 32, 34 is positioned on the carrier arm 6 with the nozzles 32, 34 pointing in opposite directions, such that the heat exchanger tubes 42 on both sides of the carrier arm 6 can be hit by the jetted fluid.

When in use, the cleaning device 4 jets a fluid, e.g. pressurized air with solid particles, such as sand, from the nozzles 32, 34, whereby the nozzles are rotated around the second rotation axis R1. Fig. 2a shows the original position of the nozzles 32, 34, and Fig. 2b shows the nozzles when rotated. By rotating, the jet of fluid can be directed through the rows of tubes, ensuring that every tube in the matrix is hit with sand and thereby cleaned.

Fig 3a. shows a cross-sectional side view of the cleaning device 4, which is connected to the carrier arm 6 with a connecting part 8 which surrounds the carrier arm 6. The connecting part 8 is configured to linearly move on the carrier arm 6 by a drive means 12 that is positioned in the connecting part 8. The nozzles 32, 34 are fixed on the carrier arm 6 with a nozzle holder 31. A drive means 36 positioned in the connecting part 8 is configured to rotate the nozzles back and forth between a range of angles, such as from -10 — 10°. And when the carrier arm 6 rotates, the nozzle holder and therewith the nozzles thus move as well. The carrier arm 6 is configured to rotate intermittently as it moves back and forth between a range of angles, such as from -30 - 30°. Fig. 3a shows the cleaning device 4 on the carrier arm 6 in its original position, and Fig. 3b shows the position of the carrier arm 6 and the nozzles 32, 34 when the carrier arm 6 is rotated around the longitudinal axis L of the carrier arm 6.

Claims

CONCLUSIONS

A system for cleaning an object, especially the outside of incinerator heat exchanger tubes (42), comprising a cleaning device (4) with one or more nozzles (32, 34) configured to spray a liquid coupled to a support arm (6), the cleaning device being configured to move linearly in the longitudinal direction of the support arm (6), to rotate in a first direction of rotation about a first axis of rotation (R1) parallel to the longitudinal axis (L) of the support arm (6), and rotate in a second rotational direction about a second rotational axis (R2) perpendicular to the first rotational axis (R1).

A system according to claim 1, wherein the cleaning device (4) comprises a connecting part (8) by which the cleaning device (4) is coupled to the support arm (6), the connecting part (8) being configured to move linearly in the longitudinal direction of the support arm (6).

The system according to claim 1 or 2, wherein the support arm (6) is configured to rotate about its longitudinal axis (L) to rotate the cleaning device (4) in the first direction of rotation about the first rotational axis (R1) parallel to the longitudinal axis ( L) of the support arm (6).

The system of claim 3, wherein the system further comprises one or more fasteners (16, 18) for attaching the support arm (6) to a support system, and wherein the support arm (6) is rotatable in the attachment means (16, 18) is mounted to allow the support arm (6) to rotate about its longitudinal axis (L).

A system according to any one of the preceding claims, wherein the nozzles (32, 34) of the cleaning device are configured to rotate relative to the connecting member (8) about the second rotational axis (R2).

A system according to any one of the preceding claims, wherein the cleaning device (4) is configured to spray solid particles from the one or more nozzles (32, 34).

A system according to any one of the preceding claims, wherein the cleaning device (4) comprises two or more nozzles (32, 34) configured to spray liquid in opposite directions.

A system according to any one of the preceding claims, further comprising a support system perpendicular to the longitudinal axis (L) of the support arm (6), the attachment means (16, 18) being attached to the support system, and the attachment means (16, 18) are configured to move linearly on the support system.

A system according to any one of the preceding claims, further comprising drive means (12, 30, 36) for performing the linear and rotational movements, the drive means (12, 30, 36) preferably being pneumatic motors.

A system according to any one of the preceding claims, further comprising a controller for remote control of at least the drive means (12, 30, 36) and/or the cleaning device (6).

A system according to any of the preceding claims, wherein the cleaning device (4) comprises one or more sensors configured to provide a sensor signal representative of the position of an object, such as tubes of the heat exchanger of the incinerator (42 ).

A system according to claim 10 or claim 11, wherein the controller is configured to control the driving means (12, 30, 36) and/or the cleaning device (6) based on the sensor signal.

A system according to any one of claims 9 - 12, wherein the drive means (12) arranged to move the cleaning device (4) linearly in the longitudinal direction of the support arm (6) comprises a rack and pinion system.

A system according to any one of the preceding claims, further comprising a container for liquid, in particular a liquid with solid particles, which is connected in a flowable manner to the cleaning device (6).

A method of cleaning an object, in particular for the outside of combustion furnace heat exchanger tubes (42), using the system according to any one of the preceding claims, comprising the step of spraying a cleaning agent from one or more nozzles (32 , 34) while the cleaning device moves linearly in the longitudinal direction of the support arm (6), and/or rotates in a first direction of rotation about a first axis of rotation (R1) parallel to the longitudinal axis (L) of the support arm (6), and/or rotates in a second direction of rotation with a second axis of rotation (R2) perpendicular to the first axis of rotation (R1).

A method of cleaning an object according to claim 15, wherein the attachment means (16, 18) are moved linearly on the support system in a direction perpendicular to the longitudinal axis (L) of the support arm (6).

A method of cleaning an object according to claim 15 or 16, wherein at least the driving means (12, 30, 38) and/or the cleaning device (4) are remotely controlled by an operator.