Patent Application
20170292279
None.
Cokers or coker units are processing units which are used in industrial plants such as oil refineries for converting the residual oil from a vacuum distillation column or a so-called atmospheric distillation column into low molecular weight hydrocarbon gases, naphtha, light and heavy gas oils, and petroleum coke. The process thermally cracks the long chain hydrocarbon molecules in the residual oil feed into shorter chain molecules leaving behind the excess carbon in the form of petroleum coke. Major steps of the aforementioned coking process take place in so-called coking or coker drums. Larger coker units may have tandem pairs of coker drums, some with as many as 10 drums, each of which may have diameters of up to 10 meters and overall heights of up to 50 meters. The drums are often made from a non-flammable and chemically resistant material such as stainless steel.
During the initial construction phase of the coker units at the construction site of the industrial plant, a scaffolding is required which serves as a temporary structure to support a work crew and materials inside the coker drum. This allows installation work, in particular in the region of the drum inlet/outlet ports on the uppermost portion of the drums. The aforesaid scaffolding may also be used for maintenance and repair work on the inside of the coker drums. The drums, at their lower end, have an opening which, during use of the drums, is sealingly closed by a cap. Further, the coker drums typically show a narrowed, in particular conical, lower longitudinal portion with an inclined or concave flank. In praxis, it is this flank which is generally used for a vertical support of the scaffolding inside the drum. However, due to the relatively high mass of the scaffolding the drum wall which is generally not structured and designed for such high loads, may be overly stressed and thereby damaged. Also, there is quite a risk that an inner coating of the drum may be scratched by the scaffolding which necessitates costly finishing work on the inside of the drum.
It is, therefore, the object of the invention to provide a scaffolding arrangement with a scaffolding which may be easily mounted and by which the aforementioned damages to the coker drum can be reliably prevented.
The scaffolding arrangement according to the invention has a scaffolding assembled from individual scaffolding components for internal construction or maintenance work within a coker drum standing upright on the ground and which has a lower end portion with a cross-section which tapers in the direction of the longitudinal axis of the drum towards a closable opening at the lower end of the coker drum. The scaffolding comprises
According to a further embodiment of the invention, the support posts of the lower support section of the scaffolding may be fixed to a common base plate. The base plate is directly supported on the ground and further enhances the mechanical stability, in particular with respect to an unwanted tilting of the scaffolding, during use.
According to a yet further embodiment of the invention, at least part of the support posts of the lower support section of the scaffolding are connected to each other by a plurality of horizontally arranged crossbeams and/or diagonally arranged beams.
According to a further embodiment of the invention, the scaffold tower section of the scaffolding has outriggers which project laterally from the scaffold in the direction of a vertically oriented inner wall surface of the coker drum. These outriggers may serve as an additional safety feature so as to preclude a potentially dangerous tilting of the scaffolding. Preferably, the outriggers are each designed and dimensioned to leave some (lateral) play between the outrigger and the wall of the coker unit. If there is a tilting moment exerted on the scaffolding, at least some of the outriggers will abut against the wall of the coker and thereby limit the degree of tilting. The outriggers may be provided with a flexible, e.g. rubber-elastic, contact body to prevent any scratching of the inner wall surface of the coker drum wall.
According to a further embodiment of the invention, the support frame is connected to the upper end of the said support section.
According to a preferred embodiment of the invention, the support frame of the lower support section of the scaffolding may be additionally braced by horizontal, vertical and/or diagonal braces which are preferably detachably attached to the support posts of the lower support section of the scaffolding.
According to a further embodiment of the invention, there is provided a ladder which is attached to the support section of the scaffolding and which extends through the opening of the lower section of the coker drum into the coker drum. Thereby, the first working platform of the scaffolding can be easily reached from below and outside the coker drum.
According to a further embodiment of the invention, the scaffold tower section has a plurality of further working platforms which are accessible from the first working platform by means of a staircase arrangement. The staircase arrangement is advantageously at least in part helically arranged around the longitudinal axis of the coker drum. By this, an unwanted tilting moment being exerted on the scaffolding can be more reliably prevented during use of the scaffolding by workers.
For a fuller understanding of the nature and objects of the invention, reference is made to the following detailed description taken in connection with the accompanying drawings wherein:
Reference is now made to
The coker drum 12 may have an overall diameter 18 of up to approximately 12 meters (≈39,4 feet) and an overall height 20 of up to 50 meters (≈164 feet).
A longitudinal axis of the coker drum 12 is denominated 22. The coker drum 12 has a top end portion 24, an intermediate portion 26 and a bottom or lower end portion 28. Lower end portion 28 has an opening 30 which, during use of the coker drum 12, is sealingly closed with a cap or hatch not shown in
The coker drum 12 features several fluid ports 36 such that fluids (e.g. educts, reactants) may be fed into and discharged from the interior chamber 32 of the coker drum 12. The fluid ports 36 may be located at the top end portion 24 of the coker drum 12 as is shown in
As can be seen from
A scaffolding generally denominated 38 serves as a temporary structure to support a work crew as well as materials inside the drum 12 during construction, maintenance and/or repair of the coker drum 12. For instance, when setting up the coker drum for its first use, the fluid ports 36 at the top end portion 24 need to be accessed from the inside for the installation of pipes, sensors and so forth.
The scaffolding 38 is assembled from a plurality of prefabricated scaffolding components which are all compatible with each other. Said scaffolding components may all belong to a manufacturer-specific scaffolding system or to scaffolding systems of different manufacturers which are compatible with each other. Compatibility is to be understood as the interchangeability, functional and technical equality as well as material equality of the respective scaffolding components.
The scaffolding 38 comprises a lower support section 40 and a scaffold tower section 42 which is located above and supported on said lower support section 40. The lower support section 40 has several longitudinal support posts 44 each having a lower and an upper end 44a, 44b. The support posts 44, with their lower ends 44a, are being supported outside of the coker drum 12 on the ground. The support posts 44 may be arranged or fixed to a base plate 46 which directly contacts the ground 16 and by which a stable and non-tilting position of the support posts can be ensured. The support posts 44 are further arranged spaced apart to provide a multi-point support of the scaffolding 38. Each of the support posts 44 are aligned vertically and extend through the opening 30 provided on the lower end portion 28 of the coker drum 12 right into the interior chamber 32 thereof. It is appreciated that each support post 44 may be formed in one or, preferably, in multiple parts.
There is a support frame 48 which is attached to the upper ends 44a of the support posts 44. The support frame 48 comprises a plurality of frame members 48a, 48b which extend in a horizontal direction. The frame members 48a, 48b are detachably interconnected with each other, e.g. by bolts, which is not shown in detail in
As can be seen in more detail from
The scaffold tower section 42 comprises further working platforms 52b-52h which are arranged spaced apart from one another and aligned with each other in the vertical direction. These further working platforms 52b-52h are located in the intermediate portion of the coker drum and may therefore, extend laterally beyond the first working platform 52a. The working platforms 52b-52h may, therefore comprise a different number of boards (not shown in the Figures) than the first working platform 52a. The scaffold tower comprises a plurality of common scaffolding components such as vertical posts 54a, crossbraces 54b, diagonal braces 54c, toe boards 54d, guardrails 54e and the like which are detachably connected to one another.
The aforementioned scaffolding components of the scaffold tower section 42 may all or at least in part consist of aluminum to thereby facilitate an assembly of the scaffolding 38. The scaffolding components, in particular the support posts 44 of the lower support section 40, are preferably of steel to thereby ensure a sufficient load-bearing capacity thereof.
There is a ladder 56 provided by which the first working platform 52a is accessible from below and the outside of the coker drum 12 via the opening 30 at the lower end portion 28. The ladder 56 can be affixed to one or more of the support posts 44 of the lower support section 40 of the scaffolding 38.
The further working platforms 52c-52h of the scaffold tower section 42 may be accessible from the first platform 52a by means of a staircase arrangement 58 which, overall, may be helically arranged around the longitudinal axis 22 of the coker drum 12. The helical arrangement helps to counteract an unwanted tilting moment which is exerted on the scaffolding 38. In the Figures, the staircase arrangement 58 is only partially shown due to the limitations of the sectional representation of the scaffolding 38.
The scaffold tower section 42 may, in particular in a region higher up, have outriggers 60 which project laterally from the scaffold tower in the direction of the vertically oriented inner wall surface 34a of wall 34 of the coker drum 12. The outriggers 60 serve as an additional safety feature and provide an additional (multiaxial) lateral support to the scaffolding 38 in case that there is any tilting of the scaffolding during use. However, it needs to be noted that there, preferably, is some lateral play between the outriggers 60 and the wall 34 of the coker drum 12 during normal operation of the scaffolding 38.
As can be seen from the Figures, vertical loads F of the scaffolding 38 as a whole, are solely transferred to the ground 16 via the said lower support section 40 of the scaffolding 38. The scaffolding 38 does neither abut against the wall 34 in the tapered lower end portion 28 of the coker drum 12 nor against the wall 34 in the intermediate or top end portion 26, 24 such that there is no load transmission into said coker drum by the scaffolding 38 at all. In other words, the scaffolding is fully self-supporting. Thereby, a hazardous strain to the coker drum can be reliably prevented. Despite this, the scaffolding 38 still offers the full functionality which is necessary for the respective installation, maintenance and/or repair work to be performed within the coker drum.
