A SYSTEM OF SLOT OPENING FOR REDUCING METAL STRESS IN COKE DRUM AND AN APPLICATION METHOD THEREOF

Technical Field

This invention relates to a system and an application method for opening slot(s) on coke drum supporting member (drum skirt(s)) by metal cutting method to reduce damage caused by thermal stress due to varying temperatures in coke drums.

Prior Art

Coke drum(s) is a type of vessel that mainly uses heat to refine complex and/or large hydrocarbons into lighter, more useful products such as; gasoline, diesel, fuel and jet fuel by thermal processing in petroleum refineries.

Coke drums are the main part of coker units and serve as the final step in the cracking process. Coke drums are formed of a main drum part and a supporting member (skirt part / drum skirt) welded to said main drum and supports said main drum part. Coke drum(s) and/or supporting member(s) are normally constructed of low alloy steel to improve the resistance of the drum for bulging during the drum operating cycle and also the coke drums are clad with a layer of corrosion resistant alloy to prevent corrosion. Choosing of the construction material is very important to design the life cycle of the drum. Another very important parameter to extend the designed life time of a coke drum is external applications (escpecially mechanical applications) in coke drums and/or supporting member by reducing the metal stresses and preventing or reducing the thermal expansion.

It has been known in the prior art that the conventional coke drums are carried on metal support members (drum skirt) and that metal support members are connected to coke drums by welded joints. It is again a common practice in the prior art that the coke drums and supporting metal members are insulated by using different kinds of insulation materials to preserve energy loss. Coke drums are used in coking process that involves very high temperatures, up to 500- 600°C. During the operation in coking process, the temperature rises up to 500°C and then falls rapidly to decreased temperature up to 100°C, by cooling down the drum by quenching water or any other known techniques. Coke drum shell experiences high bending stress during the fill cycle as the hot feed fills the drum and the hot liquid level rises in the drum, and conversely, as the quench water level rises in a hot drum, cooling the drum. These cyclic and reversing bending stresses have a significant effect on the fatigue life of the drum. The consequence is that; the shorter the drum cycle is, the more severe are the temperature gradients in the drum and the shorter is the drum life time.

During heating and cooling operations in coking cycle, there has been a metal stress in coke drum and its supporting skirt structure. It causes damages in coke drum structure and/or supporting member structure and reduces the life time of the drum. There has been crack(s) formed in coke drum and supporting member.

Due to that rapid temperature changes, the coke drum tends to bend mainly from welding parts of supporting member (whihc is also known as banana effect syndrome) and there has been cracks on the supporting member that carries the drum. These cracks sometimes make the coke drum totally unusable or irreparable.

High amount of money is spent to repair the drums and the loss from the disruption of the production could cost even much higher.

According to API recommended practice 571 , damage mechanisms are affecting fixed equipment in the refining industry such that coke drums are affected by thermal fatigue failure mechanism. Due to the high stress on the skirt part of the coke drum and according to the API 934G (about the design and repair of coke drums), key slot opening is a recommended action to be taken on coke drum skirts.

It has been known in the art that cutting some parts of the supporting member by the way of opening slit(s) or slot(s) extends the life of the coke drum by decreasing the stress and the risk of thermal fatigue and increasing the flexibility of the drum skirt. There are relatively few studies about how to open slit(s) / slot(s) on supporting member which made of metal. It has been known that; cutting the skirt by jet water, plasma or flame can be used as alternative methods for opening that slot(s) on the supporting member. But it has been also known that, using that methods may cause deformation of drum material irrevocably that damages the coke drum and decreases fatigue life of coke drums.

Flame cutting of the supporting member (drum skirt) will cause the disadvantage of applying excessive and local heat to the drum skirt. Morever, after gouging the slots with flame cutting method, chamfering the upper and lower end edges of the slot within strict tolerances is very difficult on rough surface. Besides, local hardness of drum skirt increases due to the excessive heat input and this can cause unexpected cracks on the drum skirt and machining will be very difficult on that hard surface.

US patent no. 2,802,596 is one of the published documents discloses the thermal expansion problem of the coke drums and mentions the need of opening slots on coke drum supporting member structure. This patent document focuses on flame cutting of supporting member (coke drum skirt), that will cause the disadvantage of applying excessive and local heat to the skirt. These will probably damage the hot box, skirt and coke drum cone section irrevocably.

US patent application no. 5,891,310 discloses reducing thermal stress at the area around the welds of the drum skirt by applying external heat to the drum at the area of the drum-to-skirt junction, that can accordingly reduce thermal stress. In the patent application, the skirt includes a series of slots extending from the top of the skirt, to prevent stress risers from forming at the slot ends. But this document does not disclose formation of slots and also the position of slots are extending from top of the skirt.

To be mainly used in the refining industry, there is a need of improved method and system about opening slit(s) / slot(s) on the coke drum supporting member (drum skirt) to increase the life time of coke drums. Brief Description of Invention

A system suitable for opening slots and/ore holes on a supporting member of a coke drum is developed with the present invention. The system comprises at least one panel comprising a back surface, which is facing the supporting member during slot opening operation, and a front surface opposite to the back surface; at least one first lifter which is provided on the panel, which is suitable for being used to attach the panel on the support member and at least one machining tool for opening of the slot and or hole.

Thanks to the system of the present invention, damage caused by thermal stress due to varying temperature changes in coking operation is reduced.

Object of Invention

The object of the present invention is to provide a mechanical system and an application method to open slot(s) on coke drum supporting member (drum skirt).

Another object of the invention is to provide a system and an application method for opening slot which extends the fatigue life of coke drum.

A further object of the present invention is to provide a system and an application method for opening slot which extends the fatigue life of coke drum by reducing metal stress mainly at the area around the coke drum supporting member.

Still another object of the present invention is to provide a system and an application method which is more useful and feasable to open slots on supporting member of the coke drum comparing to known techniques in the prior art.

Yet another object of the invention is to provide a system and an application method for opening slots which does not damage the coke drum structure during the slot opening operation.

Another object of the invention is to provide a system and an application method suitable for opening slot(s) and/or hole(s) employed on-site applications. Brief Description of The Drawings

The objects of the present invention will become more comprehensible from the following description and the claims, taken in conjunction with the accompanying drawings. These drawings are given to show the principles of the system used to apply the slot opening operation on the support member of a coke drum according to present invention and to show the state of the art. The following drawings therefore are not to be considered limiting the scope of the invention. The invention will be described and explained with additional reference numbers given below and specified through the use of the accompanying drawings in which:

Figure 1A is a schematic view of a coke drum showing joining pieces of support member to the shell of the coke drum

Figure 1 B is an extended total view of support member of the coke drum

Figure 2 is a schematic view of a bended coke drum showing the gradual annular bending.

Figure 3 is a partially cut away of drum skirt, showing details of the supporting member (skirt) having slot openings and corresponding drilled holes.

Figure 4A is a cross sectional view of the system on the panel in rest position.

Figure 4B is a cross sectional view of the system on the panel in working position.

Figure 5A is a schematic view of the system in rest position involving the panel comprising the mechanical equipments to open the slot(s) and corresponding drilled hole(s).

Figure 5B is a schematic view of the system in working position involving the panel comprising the mechanical equipments to open the slot(s) and corresponding drilled hole(s).

Figure 6A is different schematic views of the deburring tools.

Figure 6B is schematic view of ball shaped deburring tool being inserted into the hole(s). Figure 7 is a schematic view of a carrier assembly comprised by system of the present invention

Figure 8 is an exemplary perspective view of the panel comprised by system of the present invention.

Figure 9 is another exemplary perspective view of the panel comprised by system of the present invention. The following reference signs are given to illustrate the drawings more clear.

10: Coke Drum

11 : Body

12: Supporting member

13: Upper plate

14: Bottom plate

15: Slot

16: Hole

18: Joining part

19: Carrier assembly

19a: Rod

19b: Eyebolt

19c: Second lifter

19d: Chain hoist

19e: Locking equipment

20: Panel

20a: Front surface

20b: Back surface

21 : Cutter

21a: Movement member

22: Drill

23: First lifter

24: Gap

25: Deburring tool

26: Movement assembly

27: Handle

28: Lower guide

29: Holding body

30: Lever

31 : Centering pin

A: Detail Description of Invention

In the art, coke drums are used for the thermal processing of heavy petroleum oils and this thermal process comprises heating and cooling operations. During heating and cooling operations in coking cycle, there has been a metal stress in coke drum and its supporting member (which is also known as drum skirt). It causes damages in coke drum structure and/or supporting member structure and reduces the life time of the drum. Furthermore, there has been crack(s) formed on the coke drum and the supporting member due to thermal change occuring in the coke drum during coking cycle. In addition, due to that rapid temperature changes, the coke drum tends to bend mainly from welding (joining) parts of supporting member and this can also cause cracks on the supporting member that carries the drum. These cracks sometimes make the coke drum totally unusable or irreparable. In Fig. 2 bending problem being occurred during that temperature changes is shown. As shown in Fig. 2, the coke drum (10) bending structure shows a curved shape of a coke drum (10) showing the gradual annular bending near the joining part (18) (i.e. welding part) of the coke drum (10) to the supporting member (12). The deformation of supporting member (12) can not stand the force and starts to crack due to that rapid temperature changes from different parts which will cause irrevocable damages. Furthermore, in many preferable coke drum (10) designs, the attachment of the supporting member (12) to the bottom of the coke drum is basically consisted of a simple fillet weld and this type of weld causes very high stress and leads to undesired fatigue cracking on the body and the supoorting member (12) of the coke drum. In order to eliminate these problems, opening of slots on the supporting member (12) and preferably keyholes provided at the both ends of the slots is a preferred and proposed operation. However, the prior art techniques for opening slots on the supporting member (12) and keyholes may cause deformation of drum material irrevocably that damages the coke drum (10) and decreases fatigue life of coke drums (10). For instance in the technique opening the slots with flame, chamfering the upper and lower end edges of the slot within strict tolerances is very difficult on rough surface. Besides, local hardness of supporting member (12) increases due to the excessive heat input and that can cause unexpected cracks on the supporting member (12) and machining will be very difficult on that hard surface. These will probably damage the hot box, the supporting member (12) and the coke drum (10) cone section irrevocably. Moreover, avoiding sharp edge intersection of the slot with the holes provided at both ends of the related slot and providing smooth surface edges including intersection it is very important. In the prior art, this can be achieved by opening the hot-box to work from inside of the skirt part which is the area between the skirt part and the bottom plate (14) of the coke drum (10). However, opening the hot-box will create a problem of premature cracking as cyclic thermal stress at upper keyholes. For the mentioned reasons; in the present invention, a system and an application method thereof for opening slots on the supporting member of a coke drum which is eliminating above-mentioned problems is disclosed.

Fig. 1A illustrates a general view of a coke drum (10). The coke drum (10) has a body (11) which is preferably cylindrical and an upper plate (13) and a bottom plate (14) provided on the opposite ends of the body (11). A supporting member (12) (in other words drum skirt) which has preferably a cylindrical shape is attached around the boundary between the body (11) and the bottom plate (14) of the coke drum (10). A detailed view of the supporting member (12) is also shown in Fig. 1 B in a total view. The supporting member (12) is configured to be fixed, preferably welded from a joining part (18), onto the body

(11) of the coke drum (10) preferably with submerged arc welding (SAW) technique or gas shielded metal arc welding (GMA) technique.

Typically, the supporting member (12) is constructed from any type of steel such as; stainless steel, alloy steel, carbon steel, plain steel. Preferably the supporting member

(12) is constructed from plain steel and low alloy steel.

The system of the present invention is suitable for opening slots (15) and/or holes (16) on the supporting member (12) of the coke drum (10) as shown in Fig. 3. The system, schematic views of which are given in Fig. 4A, 4B, 5A and 5B, comprises at least one panel (20) comprising a back surface (20b), which is facing the supporting member (12) during slot opening operation, and a front surface (20a) opposite to the back surface (20b) and not facing the coke drum (10) during slot opening operation; at least one first lifter (23), preferably a magnetic lifter, which is provided on the panel (20), preferably on the front surface (20a) of the panel (20), and which is suitable for being used to attach the panel (20) on the supporting member (12) and at least one machining tool for opening of the slot (15) and/or hole (16) provided on the panel (20), preferably on the front surface (20a) of the panel (20). The machining tool preferably comprises at least one (preferably at least two which are located opposite to each other) drill (22) which is used for opening the holes (16) and at least one cutter (21) which is used for opening the slots (15). Thanks to the system of the present invention, the slots (15) and/or holes (16) are opened without applying heat onto the supporting member (12) and/or body of the coke drum (10). According to the present invention, preferably there are four first lifters (23) that are attached on the corners of the panel (20). Said first lifter (23) preferably comprises a holding body (29) which is able to have magnetic property, which ensures the attachment of the panel (20) to the supporting member (12) when it is magnetic and ensures detachment of the panel (20) from the supporting member (12) when it is not magnetic and the first lifter (23) further comprises a lever (30) which has an on position and an off position and which ensures the holding body (29) is magnetic when it is at the on position and the holding body (29) is not magnetic when it is at the off position.

Thanks to the system of the present invention and slot opening operation performed by the system, the coke drum (10) comprises slot(s) (15) and corresponding drilled hole(s) (16) which are opened by said system and provided on the supporting member (12) as shown in Fig. 3, to extend the fatique life of the coke drum (10).

In a prerefable embodiment of the present invention, a saw or a grinder can be used as cutter (21) to open the slot(s) (15) by cutting a part of the supporting member (12).

In other prerefable embodiment of the present invention, any type of a drill (22) can be used to drill the hole(s) (16) on the supporting member (12).

In an alternative embodiment, the drill (22) is directly attached and fixed on the panel (20) or the drill (22) is attached on the panel (20) with a pivotable manner by means of a hinge.

The panel (20) of the system of the present invention can be made from any kind of steel such as; structural steel, carbon steel or stainless steel.

In an alternative embodiment of the present invention the panel (20), preferably back surface (20b) of the panel (20) has a curved structure such that when panel (20) is attached to the supporting member (12) it is able to match up with the outer surface of the supporting member (12). In another alternative, as shown in figure 9, the panel (20) comprises at least one lower guide (28) provided on the back surface (20b) and having a curved structure such that when the panel (20) is attached to the supporting member (12), it is able to match up with the outer surface of the supporting member (12).

In one embodiment of the present invention, the system further comprises at least one movement assembly (26), as shown in figure 8, preferably provided on the panel (20) (more preferably on the front surface (20a) of the panel (20)), in connection with the cutter (21) such that the movement assembly (26) ensures the movement of the cutter (21) in the slot (15) cutting direction for creating the slot (15) on the supporting member (12). Said movement assembly (26) preferably comprises a rail/slide mechanism ensuring linear movement of the cutter (21). Said movement assembly (26) preferably further comprises at least one handle (27) in connection with the rail/slide mechnanism in order to ensure the controlling (preferably by manually) of the movement of the cutter (21) on the rail/slide mechanism.

In yet another alternative embodiment of the present invention, the system further comprises at least one movement assembly (26), as shown in figure 8, preferably provided on the panel (20) (more preferably on the front surface (20a) of the panel (20)), in connection with the drill (22) such that the movement assembly (26) ensures the movement of the drill (22) in order to provide suffient working area for the cutter (21) for slot (15) opening process. Said movement assembly (26) preferably comprises a rail/slide mechanism ensuring linear movement of the drill (22). Said movement assembly (26) preferably further comprises at least one handle (27) in connection with the rail/slide mechnanism in order to ensure the controlling (preferably by manually) of the movement of the drill (22) on the rail/slide mechanism.

The system of the present invention preferably comprises at least one centering pin (31) provided on the panel (20) in order to reinforcing the attachment of the panel (20) to the supporting member (12).

In the other preferable embodiment the system further comprises at least one controller in connection with the machining tool in order to ensure the control of the slot (15) and/or hole (16) opening process. In another preferable embodiment of the present invention, as shown in figure 7, the system comprises at least one carrier assembly (19) which is in connection with the panel (20), which is suitable for being attached to the coke drum (10) and which ensures the movement of the panel (20) with respect to the coke drum (10) during slot (15) and/or hole (16) opening operations. Said carier assembly (19) preferably comprises at least one rod (19a) which is preferably positioned in a plane parallel to a surface plane of the panel (20); at least one eyebolt (19b) through which the rod (19a) passes (preferably there are provided at least two eyebolts (19b) through which the rod (19a) passes and which are positioned on the rod (19a) in an opposed manner); and at least one second lifter (19c), preferably a magnetic lifter, which is connected to the rod (19a) (preferably at least two second lifters (19c) provided on the rod (19a) in an opposing manner), which is suitable for being used to attach the rod (19a) to the coke drum (10) and preferably on which the said eyebolt (19b) is provided in order to ensure the connection of the second lifter (19c) to the rod (19a) such that the rod (19a) is able to move in the direction extending in the longitudinal axis of rod (19a) preferably sliding in the eyebolt (19b). Said second lifter (19c) preferably comprises a holding body (29) which is able to have magnetic property, which ensures the attachment of the rod (19a) to the supporting member (12) when it is magnetic and ensures detachment of the rod (19a) from the supporting member (12) when it is not magnetic and the second lifter (19c) further comprises a lever (30) which has an on position and an off position and which ensures the holding body (29) is magnetic when it is at the on position and the holding body (29) is not magnetic when it is at the off position. The carrier assembly (19) further comprises at least one other eyebolt (19b) (preferably at least two eyebolts (19b) next to each other) provided on the panel (20) and at least one chain hoist (19d) is connected to the eyebolts (19b) provided on the rod (19a) and on the panel (20), in order to ensure the connection of the rod (19a) and the panel (20) to each other and ensure the movement of the panel (20) with respect to the coke drum (10) such as in vertical direction for opening a slot (15) and in horizontal direction while rod (19a) is moving for opening another slot (15) after the end of the opening operation of the previous slot (15). In an alternative the carrier assembly (19) comprises en least one another eyebolt (19b) provided on the rod (19a) corresponding the the eyebolt (19b) provided on the panel (20). Therefore, the chain hoist (19) is able to be connected to the rod (19a) in a straight manner and ensures more stable movement of the panel (20) and the rod (19a). In another embodiment, the carrier assembly (19) preferably further comprises at least one locking equipment (19e) which is preferably provided on the rod (19a) and which ensures the ending of the movement of the second lifter (19c) in order to stop the carrier assembly (19) in a desired position when the panel (20) is brought to the desirable position with respect to the coke drum (10).

In a preferable embodiment, the chain hoist (19d) can be shortened and/or extended according to the location of the slot (15) and/or hole (16) opening.

In one embodiment of the present invention, at least one deburring tool (25) is used for chamfering. Preferably there are four different deburring tool structures (25) shown in Fig. 6A that can be used at the rear, and/or the front side of opened slot(s) (15) and holes (16). But any other types of deburring tools (25) can be used also, that having different structures.

Avoiding sharp edge intersection of the slot (15) with the holes (16) provided at both ends of the related slot (15) and providing smooth surface edges including intersection is very important in a slot opening operation. For that reason, this is achieved by performing a drilling process by use of a drill (22) from the front side (in other words external side which is seen from the external environment or which is not facing the bottom plate (14) of the coke drum (10)) of the supporting member (12) while opening hole(s) (16). On the other hand it is hard and/or not suitable to perform drilling from the inside of the supporting member (12) which is the area between the supporting member (12) and the bottom plate (14) of the coke drum (10). For that reason, the deburring tool (25) is used to smooth out the sharp edges during hole (16) to slot (15) cutting. In the deburring process, the deburring tool (25) is inserted into the hole (16) from outside to the inside of the supporting member (12) and smoothing operation is able to be performed from the inside of the supporting member (12). Smoothening inside edges (inside of the supporting member (12)), especially the intersection of the slot (15) and the upper hole (16), instead of opening the hot-box to work from inside, which is the prior art technique, is very important because, opening the hot-box will create a problem of premature cracking as cyclic thermal stress at upper keyholes. Thanks to the system and slot opening operation provided by the system, discontinuity due to sharp edges of the hole (16) and intersection of the slot (15) and the hole (16) is avoided. In one embodiment of the present invention, chamfering of the rear side of the slot (15) and hole (16) is able to be done from the front side of the slot (15) and hole (16). There is no need to open hot box (inner side insulation of skirt) section of the coke drum (10) that makes the system user friendly and functional. Figure 6B shows a schematic view of an exemplary ball shaped deburring tool (25) being inserted through the hole (16) from the outside of the supporting member (12). The application would require the deburring tool (25) to be moved around the inside of the hole (16) circumference to remove the sharp edges created by the drill (22). The same method can be used to remove the sharp edges from the inside of the slot(s) (15) if necessary. In that case, the deburring tool (25) must have appropriate width which is suitable for slot opening.

The deburring tools (25) usually have different shapes of end edges for the desired application area and typically made from HSS (high speed steel).

According to the present invention, a ball shaped deburring tool (25) is preferred for chamfering inside sharp hole (16) edge and smoothen the area of stress inside and/or outside of the supporting member (12).

According to the present invention there is provided a gap (24), preferably a lengthwise gap (24), on the panel (20) extending on the slot (15) cutting direction and into which the cutter (21) places for reaching the supporting member (12) to open the slot (15) on the supporting member (12) by passing through the gap (24). For instance, in a preferable embodiment, the cutter (21) has a round shape rotating around an axis and has teeth for cutting the slot (15) and these theeth fit into that gap (24) to cut the support member (12). The length of the gap (24) is preferably longer than the slot (15) desired to be opened on the supporting member (12).

In another embodiment of the present invention the system comprises at least one opening (not shown in figures) corresponding to at least one drill (22) and ensuring the drill (22) to reach the supporting member (12) for opening the hole (16) on the supporting member (12) by passing through the opening.

In another alternative embodiment of the present invention, said gap (24) and said opening are integrally provided on the panel (20) as shown in figure 8. The system of the present invention further comprises at least one safety switch which is in connection with electrical components, such as machining tool, controller etc., in order to provide electrical safety during an emergency condition which can cause serious accidents.

It is very important to calculate the number of slots (15) and also the length and width of the slots (15) and the diameter of the hole (16) opened on supporting member (12). To specify the number of slots (15), the width of the slot (15) and also the diameter of the drilled hole (16) known design methods are used in the prior art. The number of slot(s) (15) is calculated by FEA (Finite element analysis). This analysis is very important to achieve the maximum efficiency from the system of the present invention.

In one embodiment of the present invention, the slot(s) (15) are opened longitudinal (L), extending along the supporting member (12).

On site applications, because of the hot box insulation of the coke drum (10), it is very diffucult and time consuming to reach the rear side of the supporting member (12). In the system of the present invention, all the machining is able to be done from the front side of the supporting member (12). With flame cutting and water jet methods, which are the known prior art techniques, it is probable to damage the hot box and coke drum (10) cone section. According to the present invention, by using the portable panel (20) with mechanical tools attached on it and by using the deburring tool (25), on site slot (15) and/or hole (16) opening application(s) is conducted in a safe and east way.

According to one embodiment of the present invention, the following steps are followed to open slots (15) and the following holes (16) in the application method;

removing the insulation material and/or shell existing over coke drum (10) supporting member (12) junction for safer execution during the cutting and/or drilling operations for opening slot(s) (15) and/or hole(s) (16),

determination of starting point of cutting of slot(s) (15) and/or drilling of hole(s) (16), to predict cutting to stagger around existing supporting member (12) longitudinal (L) seams, providing initial marking of upper holes (16) (upper edge of slots (15)) to assure center line to be on same elevation,

marking of lower holes (16) (lower edge of slots (15)) assuring vertically below upper hole (16) markers,

drilling upper and lower hole(s) (16) by using drill (22),

cutting slot(s) (15) by using the cutter (21), preferably having specified sawtooth, from the gap (24) from upper drilled hole (16) to corresponding lower drilled hole (16),

chamfering the hole(s) (16) from outside surface of the supporting member (12) by using drill (22) (in this process, the end of the drill (22) is rotated inside the hole (16) with 360° and therefore an angle is formed in the hole (16) from front side to the rear side while removing the burr),

chamfering the hole(s) (16) from inside surface of the supporting member (12) by using the deburring tool (25) (this step is performed since the drill (22) cannot be used from the inside of the supporting member (12). During this step, the deburring tool (25) is inserted into the hole (16) from front side to the rear side and an angle is formed in the hole (16) from rear side to the front side while removing the burr),

optionally deburring the slot (15) opening from inside and outside surface of the opening.

According to the present invention, the same operation cycle is followed for each slot (15) opening and its corresponding drilled holes (16).

According to the present invention, the position of slots (15) and holes (16) are marked with a marker on the supporting member (12) before cutting and drilling operations.

According to the present invention, the location of the hole(s) (16) and slot(s) (15) are determined by taking multiple dimensional measurements from reference points and sprit level checks in order to achive vertical and horizontal tolerance limits.

In one embodiment, slots (15) are cut simultaneously in same direction, either clockwise or counter clockwise. The number of simultaneous slot (15) cutting will be determined by field contractor and slots (15) are cut with precaution to avoid any damage to coke drum (10) cone e.g: hot- box etc. Dp/mp test is performed to test the slot (15) and holes (16). Finally visual inspection and dimensional check is performed.

In one embodiment of the present invention, liquid penetration (pt) and magnetic particle (mt) may be performed to examine the slot (15) locations on the supporting member (12) prior to any field cutting.

According to one embodiment of the present invention, the following steps are followed to construct the system having the panel (20) with embedded mechanical equipments;

the first lifter(s) (23), are located on the corners of the panel (20),

the drill(s) (22) are located on the panel (20) from the two points marked as to open the hole(s) (16),

the cutter (21) is located on the panel (20) from the points that will be fitted on the gap (24) of the panel (20) to open the slot (15) on support member (12).

According to the present invention the cutter (21) preferably has a dynamic profile such that, it moves through the gap (24) of the panel (20) to cut the slot (15) as shown in Fig. 5B and otherwise it pends at rest position as shown in Fig. 5A. In other words, the cutter (21) has two different positions with respect to the panel (20) such that in a first position (rest position), the cutter (21) is away from the gap (24) and it is not performing the cutting operation; in a second position it is placed in the gap (24) and reaches to the supporting member (12) through the gap (24) for opening the slot (15). In this embodiment, the system comprises at least one movement member (21a) which ensures the movement of the cutter (21) with respect to the panel (20) from one position to another.

According to the present invention, some additional machining tools can be used further such as; saw grinder and deburring grinder which are not applying high heat input.

A saw grinder can be used to grind the saw to achieve the desired saw tooth dimentions relating to calculated slot (15) dimensions. After opening the slots (15) and the drilled holes (16) and treated with these additional tools, chamfering will be considerebly easier. Additional surface treatment is not needed. There will be no crack initiation due to the excessive local heat input. This system not only improves the quality but also reduces the application time.

The coke drum mentioned in the present invention can be any type of coke drum such as; delayed coke drum, flexi coke drum or fluid coke drum. According to the present invention it is prefered and given as an example of opening the slot(s) (15) and the corresponding drilled hole(s) (16) on a delayed coke drum (10) supporting member (12).

According to present invention, more feasable system is invented that is easy to apply on coke drum (10) supporting member (12). By the improved system the damages and difficulties caused by known techniques are prevented to a large extend. According to the present invention, the life of a coke drum (10) will be extended but this needs to be calculated by using the FEA method.