Distillation: apparatus – Apparatus – Elements
Reexamination Certificate
1999-09-16
2002-07-23
Yildirim, Bekir L. (Department: 1764)
Distillation: apparatus
Apparatus
Elements
C202S239000, C202S241000, C202S243000, C202S262000, C029S426300
Reexamination Certificate
active
06423188
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to automatic or remotely operable pressure vessel units. The present invention is directed towards cokers having coke drums that are useful in hydrocarbon refineries; however, it can relate to closure devices and joint connectors for pipes, tanks and other various conduits where hazardous conditions exit, or, in situations where rapid opening and closing of a joint is desired.
The present invention, in part, comprises a remotely operable joint connector that is especially useful in cokers, where extremely high temperature and relatively high pressure exist. In particular this connector is especially suited for the deleterious effects of coke exposure or other “dirty” operations.
2. Background of the Invention
Coke drums are structures in hydrocarbon refineries, where, inside these coke drums, heat and moderate pressure turn hydrocarbon residuum into lighter products and a hard, coal-like substance—coke. A pair of coke drums cycle between coking and decoking. One coke drum is coking (joints connected and operating at about 975° F.), while the other is decoking (quenching, followed by remotely opening the joints then decoking the drum). In the decoking phase coke is removed from the coke drums by high pressure hydrostatic drilling. A drill bit is lowered into the coke drum through a drum-top deheading system and coke, cut by the drilling action, falls through a decoke chute attached to an opening in the bottom of the coke drum created when a drum-bottom deheading system removes a closure away from said opening.
Safely preparing a coke drum for decoking involves the following steps: (1) removing the working surface opening cover creating an opening in the working surface for the coke to pass; (2) remotely aligning and engaging a closure transport to the drum-bottom closure; (3) remotely energizing the drum-bottom closure to the coke drum; (4) remotely unlocking, disconnecting and separating the coke drum from the inlet pipe; (5) remotely unlocking the drum-bottom closure from the coke drum; (6) remotely disengaging the drum-bottom closure from the coke drum in a controlled manner; (7) remotely removing the drum-bottom closure from the opening in the bottom of the coke drum; (8) remotely producing and securing a passageway between the bottom opening of the coke drum to the opening in the working surface, i.e. a decoke chute; (9) remotely unlocking and moving the drum-top closure from the opening in the top of the coke drum; (10) lowering the drill bit into the coke drum through the opening in the top of the coke drum; and (11) engaging and locking the drilling head to the drum-top deheading system.
Safely preparing a decoked coke drum for coking involves the following steps: (1) remotely replacing, aligning and locking the drum-top closure to the coke drum once the drill bit is removed from the coke drum; (2) remotely decommissioning the decoke chute and replacing the working surface opening cover; (3) remotely aligning and locking the open ends of the inlet piping together, which reconnects the coke drum to the inlet pipe; (4) remotely replacing, aligning and locking the drum-bottom closure to the opening at the bottom of the coke drum.
Currently most cokers employ workers to manually perform some or all of the foregoing steps. Any of these steps can be hazardous to workers, but by far the most dangerous steps are in the transition from the coking phase to the decoking phase. Here a closed and quenched coke drum must be opened to allow the evacuation of coke from the coke drum.
Workers are most frequently harmed while performing the following steps: (1) manually unlocking, disconnecting and separating the coke drum from the inlet pipe; (2) manually unlocking the drum-bottom closure from the coke drum; or (3) manually disengaging the drum-bottom closure from the coke drum.
Coke is supposed to support itself in the coke drum when an opening is created at the drum-bottom; however, this cannot be assured. The flow of loose coke and quench water or other materials from other types of vessels can be very hazardous for workers performing functions during the opening of the vessels. This hazard exists until a secure passageway is present between the opening of the vessel and where the material is ultimately destined. In the case of a coking unit, the material is due to fall in a hole in a working surface located beneath the unit and towards an ultimate destination below the working surface. An even more hazardous environment is a coker design to produce “shot coke” where the coke will not support itself in the coke drum.
DESCRIPTION OF PRIOR ART
In many cases, the prior art sacrifices safety to provide a quick acting joint connecting means. The prior art illustrates single point failure mechanisms, where, failure of only one member could cause the integrity of the joint to be catastrophically compromised. A higher standard of safety is dictated in today's world. The present invention provides multiple fasteners, thus, providing more safety. There is a need in industry to be able to automatically and remotely open and close a joint, and those with ordinary skill in the art can appreciate, providing redundancy in the fastening means adds difficulty.
Many companies have developed quick acting connectors, but do not provide safety. Failure of these mechanisms prompted the American Society of Mechanical Engineers (ASME) to develop rules in their Boiler and Pressure Vessel Codes that give specific rules for adding safety to “Quick Acting” devices. Single acting fastening means and single point failure devices must have secondary back-up retaining elements that will assure joint integrity upon failure of the single acting fastening means or single point failure devices. Such retaining elements will complicate automated operation.
In some installations, pressure vessels, pipes, and structural joints are opened and closed manually under conditions hazardous to the people performing the operation. Most prior installations utilize joint connecting means consisting of bolted flanges that are very labor intensive. The basic closing nature of bolted flanges is illustrated in the American National Standards Institute (ANSI) Publication B16.5. Other manually operated prior art for connecting joints consist of threaded, clamped and breach-lock mechanisms. These labor intensive designs are not well suited in hazardous environments.
Coke drums are pressure vessels that have openings in the top and bottom that are periodically closed and sealed. Most coke drums have manually bolted connections connecting vessel closures and other structural units to the coke drum to close and seal the coke drums internal environment. Coke drums also have manually bolted connections connecting upstream and downstream pipes to the coke drum. Manually operating these connections has proven to be harmful to workmen.
Although prior art provides simplicity, it does not provide sufficient safety. In analyzing paths of failure, the prior art contains unsafe single component failure paths that upon failure would catastrophically cause the opening of the connected joint. A logical method to create a safe connecting means is to incorporate redundancy in the fastening elements and to remove all single point failure devices from the connecting means.
Supplying redundancy in an automatic connecting means can be difficult and expensive. Those skilled in the art will appreciate the benefit of the simple automatic operation of the present invention that provides safe redundant fastening elements. The system should be operable manually as well, when necessary due to a power failure or other interruption. When compared to other automated joint connecting means, it can be noted that a significant economic benefit is realized with the present invention due to its simplicity. This simplicity directly relates to lower operating costs and shorter down time. In some processes, one day of down time can result in an economic loss far surpassing the initial cost of t
Automated Connectors Holdings, L.P.
Locke Liddell & Sapp LLP
Yildirim Bekir L.
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