Patent Application
20160116165
Ignitors, particularly for flare stacks.
In the oil and gas industry, there are conditions that require the venting and burning of waste gases from the production process. This venting is done through devices called flare stacks. These flare stacks are elevated pipes standing vertically in the air to vent the waste gas at an elevation that is safe for toxic gas dispersion or high enough that the flare does not ignite ground level flammable items. The operating conditions in which flare stacks have to operate is very harsh and challenging. Temperatures may range from extreme cold to extreme heat in a very short time. Flaring at the flare tip may cause materials to distort or corrode due to the continuous presence of hydrogen sulphide, windy, wet and/or oily conditions. Flare stacks have to be ignited in such a way that the waste gas is burnt safely and dependably.
In an embodiment, there is disclosed an ignitor, comprising a main body supporting a center electrode having an upper part and insulators spacing the main body from the center electrode, a spark controller electrically connected to the center electrode, a sleeve having an upper end and a lower end, the sleeve being supported by the main body, the center electrode extending upwards from the main body through the sleeve and the sleeve having a part forming an outer electrode separated from the center electrode by a gap suitable for a spark to travel across the gap in response to energization of the center electrode, and the sleeve providing a flow path for air to reach the gap and being separated from the main body.
In another embodiment, there is a sparking portion of an ignitor, comprising a sleeve having a portion defining a slot, an edge of the slot forming an outer electrode, the slot having an oblong shape having a longer and a shorter dimension, the longer dimension of the slot being oriented circumferentially relative to the sleeve and a center electrode having a protruding portion protruding through the slot in the sleeve to provide an arc gap with the outer electrode, and the center electrode being spaced from the sleeve to provide a flow path for air to travel through the sleeve to the arc gap.
In various embodiments, there may be included any one or more of the following features: the sleeve and the main body may be spaced apart by at least a spacer bar; there may be a barrier between the sleeve and the main body; the barrier may be a cap secured above the main body; the cap may be spaced from the main body by a cylinder; the cylinder may provide a seal to prevent water entering the main body; the slot may be an oblong slot having a longer and a shorter dimension, wherein the longer dimension of the slot may be oriented circumferentially relative to the sleeve the protruding portion of the center electrode may be permitted to move within the slot along the axis of the longer dimension of the slot; the protruding portion of the center electrode may be arranged to move radially with respect to the sleeve; and the barrier may comprise a sealing ring which seals the sleeve to the main body; and the upper end of the sleeve may be capped.
These and other aspects of the device and method are set out in the claims, which are incorporated here by reference.
Embodiments will now be described with reference to the figures, in which like reference characters denote like elements, by way of example, and in which:
Immaterial modifications may be made to the embodiments described here without departing from what is covered by the claims.
Referring to
The sleeve 22 is preferably 3″ in diameter and made of any appropriate material that is strong and durable under high heat and corrosive conditions, but may be stainless steel. In an embodiment, the sleeve 22 is cylindrical, and is short and open at the lower end 26 to allow hot or cold condensations that form within the sleeve 22 to run freely out of the lower end 26. The upper end 27 of the sleeve 22 may be capped.
The main body 12 houses the center electrode insulators 14. The main body 12 is the primary support for the ignitor 10 and may be moved up and down the flare. At the top of the main body 12 is a barrier 28. The barrier 28 may be a cap 30 which is spaced from the main body 12 by a watershed sleeve 32. The barrier 28 inhibits moisture and heat from reaching the main body 12, for example to prevent rain and snow from coming into contact with the insulators 14. Insulators 14 may be located in the interior of the main body 12, adjacent the center electrode 16. The barrier 28 may seal the top of the main body 12. In an embodiment, the barrier 28 is a drip roof that extends over the watershed sleeve 32. The center electrode 16 preferably extends through the sleeve to a position near the top of the sleeve 22 so that the insulators 14 are separated from the burning zone below the burning zone of the flare tip, allowing the insulators 14 to remain in a dry, cool area. Keeping the insulators 14 dry and cool extends the lifetime of the insulators 14. The center electrode 16 may be rotated around as needed without doing arc on the sleeve 22.
Referring to
The center electrode 16 may be a tungsten electrode. Standard stainless steel does not like to release the electric ions in the electric arc, and regular stainless steel holds the discharging arc current and reduces the arc strength tremendously. A stainless steel electrode would hold the arc discharge, and put a back load on the discharge coil and trigger circuit and burn the coil and circuit out quickly. Tungsten is pure and releases the ions easily and completely and relieves all the back feed and weak spark problems. Depending on the embodiment, different materials may be used for the electrodes.
The outer electrode 18 may be made of tungsten or stainless steel. As shown in
As shown in
As shown in
The lower end 26 of the sleeve 22 may be sealed by a sealing ring (not shown). The sleeve 22 and the main body 12 may be separated by the sealing ring. The sealing ring may also seal the sleeve 22 to the main body 12. The sealing ring may act as a barrier to protect the insulators 14 from high heat and corrosion from flame flames extending down the sleeve 22. A protective flare tip (not shown) may be used in conjunction with ignitor 10 to provide air flow to the arc gap 40. The flare tip may be any flare tip, but preferably is a Prism V-Cool flare tip from Prism Integrated Solutions Inc., of Stettler Alberta.
Immaterial modifications may be made to the embodiments described here without departing from what is covered by the claims. In the claims, the word “comprising” is used in its inclusive sense and does not exclude other elements being present. The indefinite articles “a” and “an” before a claim feature do not exclude more than one of the feature being present. Each one of the individual features described here may be used in one or more embodiments and is not, by virtue only of being described here, to be construed as essential to all embodiments as defined by the claims.
