Rotary coke drum un-heading valve

Abstract

A rotary coke drum un-heading valve adapted for engagement to an extremity of a coke drum having an orifice therein. The rotary coke drum un-heading valve includes a valve body, having a passage which extends therethrough along a mass flow axis and at least two valve seats that circumscribe the passage. The passage is aligned for mass flow communication with the orifice. A rotatable flow obstructing member defines a bore therein and is rotatable within the valve body between an open position, wherein the bore is in communication with the passage permitting mass flow through the un-heading valve, and a closed position, wherein mass flow through the un-heading valve is prevented by the flow obstructing member. In one embodiment, the flow obstructing member is a gate pivotable in a plane perpendicular to the mass flow axis by a valve stem rotatable about its central axis which intersects the plane.

Description

TECHNICAL FIELD [0001] The present invention relates generally to a device for opening and closing a vessel containing hazardous materials, and more particularly an un-heading system for a coke drum and an un-heading valve for such a system. BACKGROUND OF THE INVENTION [0002] Delayed coking is a process employed in petroleum refineries to recover the heavy residual oil by-products left over after regular refining operations have been completed. Such recovered distillates and coke are typically emptied into large, vertical pressure vessels called coke drums or coking drums. Coke drums accordingly serve as waste disposal systems for high residual, tarry oils. Volatile fumes from the coke drums are recycled to make useful products such as gasoline and the solid material deposited in the coke drum is resold as coke for a variety of purposes. Delayed coking thus contributes significantly to the gross margin of the refineries and therefore to their overall financial performance. As such, ...

AI Technical Summary

Benefits of technology

[0011] It is another object of the present invention to provide an improved coke drum de-header valve which is compact and reliable.

[0012] Therefore, in accordance with the present invention, there is provided a rotary coke drum un-heading valve adapted for engagement to an extremity of a coke drum having an orifice therein, the coke drum un-heading valve comprising: a valve body having a passage extending therethrough along a mass flow axis and at least two valve seats circumscribing said passage, said passage being aligned for mass flow communication with said orifice; and a rotatable flow obstructing member defining a bore therein, said flow obstructing member being rotatable within said valve body in contact with said valve seats between an open position, wherein said bore is in communication with said passage permitting mass flow through said un-heading valve, and a closed position, wherein mass flow through said un-heading valve is prevented by said flow obstructing member.

[0013] There is also

Problems solved by technology

As coke drums are typically in the range of 20-30 feet in diameter and 100 feet in height, the sheer size of the heads of such drums caused their removal to be a process which was fraught with danger, both to the operators and the surrounding equipment.

Many other risks have been assumed in the past by workers who carry out the removal of such coke drum heads during the de-coking process.

Workers also run the risk of being exposed to hazardous materials and fumes from the drum when the heads are opened.

As such, attempts have been made to devise automated un-heading systems which can be remotely operated to remove at least the bottom head of a coke drum, thereby limiting the risks assumed by workers during the de-coking operation.

However, while systems such as those described above are remotely operable to minimize the risks to human operators, any procedure which requires the coke drum head to be disengaged from the drum, whether by hinged operation or otherwise, remains dangerous.

The complex nature of such mechanisms and the size and weight of the coke drum heads they displace, nevertheless leave open the possibility of catastrophic consequences

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