TW202248570A - Fluid burner head and use of fluid burner head - Google Patents

Abstract

A fluid burner head (9) for a fluid combustion unit (1), and a use of a fluid burner head (9) in a fluid combustion unit (1), are provided. The fluid burner head (9) comprises a body (11) which in turn comprises a hollow tube (13) for conveying a fluid to be combusted into a combustion chamber (5) and a cap (15) which at least partly closes an upper end (25) of the tube (13). A wall (17) of the tube (13) comprises a plurality of rows (29) of holes (27), which rows (29) extend around a longitudinal center axis (C) of the fluid burner head (9). The holes (27) permit a flow of the fluid to be combusted from an interior (49) to an exterior (51) of the tube (13). The fluid burner head (9) is characterized in that it further comprises an annular first projection (39) extending around the longitudinal center axis (C) of the fluid burner head (9). The first projection (39) projects obliquely upwards from an outer surface (43) of the body (11), above an uppermost row (29a) of holes (27) of the tube (13), with an angle α relative to the longitudinal center axis (C) of the fluid burner head (9), wherein 0 ＜ α ＜ 90 degrees.

Description

Fluid burners and their uses

The present invention relates to a fluid burner for a fluid combustion unit and its design. The invention also relates to the use of such a fluid burner in a fluid combustion unit for burning volatile gases from a fuel tank on board a ship.

In various circumstances, it may be desirable to combust a fluid, such as a gas or a mixture of gas and liquid. For example, gas combustion units are typically mounted on LNG carriers, ie tankers configured to transport liquefied natural gas, ie LNG. LNG having a vaporization temperature of -160 degrees Celsius at atmospheric pressure is contained in the tank. Even if the tanks are insulated, some evaporation of the LNG will inevitably occur and form so-called volatilities. This vapor increases the pressure in the tank and must be vented from the tank for safety reasons. Volatile gases removed from the tank can be reliquefied and returned to the tank, used as fuel on an LNG carrier, or combusted with the aid of a gas combustion unit.

A gas combustion unit may typically include a gas burner extending into the combustion chamber. The gas to be combusted is fed via the gas burner into the combustion chamber, where the gas to be combusted is ignited and burnt. Known gas burners comprise a perforated tube with an end closed by a cover. The gas is conveyed through the tubes and through the perforations of the tubes into the combustion chamber where combustion takes place in the form of a flame. When the gas pressure is relatively high, gas will be fed through the perforations at a high velocity, which will generate a flame at a distance from the gas burner. In addition, the air flow inside the tube will cool the gas burner. Therefore, the temperature of the gas burner will be kept low enough to avoid damage to it. However, when the gas pressure is relatively low, the gas will be fed through the perforations at a low velocity, which will generate the flame at a location closer to the gas burner. Furthermore, the cooling of the gas burner by the air flow inside the tube will be reduced. This can lead to extremely high temperatures of the gas burner and damage to the gas burner, typically in the area close to the closed end of the tube.

An object of the present invention is to provide a fluid burner and a use of a fluid burner, which at least partly solve the above-mentioned problems. The basic concept of the invention is to provide the fluid burner with means for forcing the fluid to burn, and thus forcing the combustion flame further away from the fluid burner. Fluid burners and uses of fluid burners to achieve the above objectives are defined in the appended claims and discussed below.

A fluid burner for a fluid combustion unit according to the invention comprises a main body. The body comprises: a hollow tube or conduit for delivering fluid to be combusted into the combustion chamber; and a cap at least partially closing the upper end of the tube. The tube further comprises a lower end for receiving fluid in the tube, ie in the interior of the tube. The wall of the tube contains a plurality of rows of holes extending around the longitudinal center axis of the fluid burner. The holes permit the flow of the fluid to be combusted from the inside to the outside of the tube, ie through the wall of the tube. The fluid burner is characterized in that it further comprises an annular first projection or protrusion extending around the longitudinal central axis of the fluid burner. The first protrusion protrudes obliquely from the outer surface of the body and protrudes above the uppermost row of bores of the tube in a direction away from the lower end of the tube (i.e. upward) at an angle relative to the longitudinal center axis of the fluid burner α, where 0<α<90 degrees. The uppermost row of holes is the row of holes arranged closest to the cover.

The first protrusion may include opposing first and second edges. The first edge and the second edge may be annular and extend along each other. The first protrusion may be directly or indirectly engaged with the body at or along the first edge and the second edge may be free.

In this document, "combust/burn" and variations thereof are used and are intended to have the same meaning.

The fluid can be a gas or a mixture of gas and liquid. As an example, the fluid may be a volatile gas from an LNG tank, such as methane or a mixture of methane and nitrogen.

The tube may comprise a mesh formed into a cylinder.

The tube may be a perforated tube and the opening may be a perforation of the tube.

The tube may be elongate, have any suitable wall thickness and have any suitable cross-section, such as circular, oval or polygonal.

The tubes may be made of any suitable material, such as metal, eg carbon steel, stainless steel or aluminium.

The longitudinal central axis of the fluid burner may coincide with the longitudinal central axis of the tube.

A plurality of rows described here means two or more rows.

The holes, openings, orifices or perforations of the tube may or may not all be of the same size and/or shape, and they may be of any suitable size and shape, such as circular, oval or polygonal. Furthermore, the holes may or may not be arranged equidistantly.

"Annulus" need not mean a circular longitudinal extension, but may mean any closed longitudinal extension, such as an elliptical or polygonal extension.

As used herein, "upper", "uppermost", "lower", "lowermost", "above", "below" etc. refer to a fluid burner when the fluid burner is oriented for its normal use made reference. In addition, the "uppermost part"/"lowermost part" means that the furthest/closest place or the surface is arranged, and the fluid combustion unit including the fluid burner is arranged on the surface.

As mentioned above, the cap at least partially closes the upper end of the tube. Here, only partially closing the upper end may for example mean that it is possible for gas to pass from inside the tube to its outside through the opening in the cap or between the tube and the cap.

The first protrusion may or may not have a uniform cross-section along its longitudinal extension, eg a constant width and/or thickness. As an example, the first protrusion may be formed as a skirt or flange. The first protrusion may be considered discontinuous if the width and thickness are zero along one or more portions of the longitudinal extension.

The first protrusion is configured to force the fluid to be burned away from the fluid burner to reduce the temperature of the fluid burner and thereby also reduce the risk of damage to the fluid burner when fluid is fed through the bore of the tube at a relatively low velocity .

The tube and cap may be integrally formed. However, according to an embodiment of the present invention, the tube and the cap are formed separately. Thereby, the tube and the cap can be replaced independently of each other when required.

The tube and cap can be made of the same material. However, according to one embodiment of the invention, the cap and the tube are made of different materials. This allows for a more flexible configuration of the fluid burner. The cover may be made of any suitable material, such as refractory concrete or metal, eg carbon steel, stainless steel or aluminium.

The first protrusion may be located anywhere between the uppermost row of holes of the tube and the upper end of the fluid burner. However, according to one embodiment of the present invention, the first protrusion protrudes from the outer surface of the body at the boundary between the tube and the cap. Without the first protrusion in place, the local temperature at the boundary between the tube and the cap tends to be relatively high. Thus, by arranging the first protrusion at the tube-cover boundary, the risk of damage to the fluid burner is minimized.

The fluid burner may be configured such that the tube and the first protrusion are formed separately. Thereby, when the first protrusion becomes worn, it can be replaced by a new protrusion without having to discard the tube and possibly the cap.

The tube may have a varying cross-section along its longitudinal central axis. However, according to one embodiment of the invention, the upper portion of the tube containing the holes has a substantially uniform cross-section along the longitudinal central axis of the fluid burner. This facilitates the production of fluid burners.

The fluid burner may further comprise an annular support extending around the longitudinal central axis of the fluid burner. The support is connectable to the first protrusion and engages with the body of the fluid burner to secure the first protrusion to the body. Such a design can facilitate the disposition of the first protrusion on the main body. As with the first protrusion, the support may or may not have a uniform cross-section along its longitudinal extension, and be continuous or discontinuous.

The fluid burner may further include an annular second protrusion extending around the longitudinal central axis of the fluid burner. The second protrusion may protrude from the outer surface of the body between the uppermost row of bores of the tube and the first protrusion. The first protrusion may or may not protrude beyond the second protrusion. The second protrusion can help force the fluid to be burned away from the fluid burner to further reduce the temperature of the fluid burner, and thereby also reduce the risk of damage to the fluid burner when fluid is fed through the bore of the tube at a relatively low velocity .

The second protrusion may protrude from the outer surface of the tube to partially shield the tube in areas where the temperature of the tube would otherwise tend to be relatively high. The risk of damage to the tube can thereby be minimized.

As noted above, the fluid burner may include an annular support extending about the longitudinal center axis of the fluid burner. The support can be connected to both the first protrusion and the second protrusion and engage with the body of the fluid burner to secure the first protrusion and the second protrusion to the body.

Whether the support is connected only to the first protrusion or also to the second protrusion, it can be engaged with the main body in different ways. As an example, it may be screwed onto the body with a tight fit so as to be held in place by friction. However, according to one embodiment of the invention, the support is clamped between the cap and the tube. By this, a precise position of the first protrusion and possibly the second protrusion can be achieved, together with a reliable engagement between the support and the main body of the fluid burner.

The cover can be designed in many different ways. According to one embodiment of the invention, it comprises an upper part and a bottom part, wherein the bottom part protrudes into the tube. Thereby, a secure and precise engagement between the cap and the tube can be achieved.

The bottom portion of the cover may comprise a portion that tapers away from the upper portion of the cover. For example, the bottom portion may be conical, and possibly frusto-conical. This produces a flow area inside the tube perpendicular to the longitudinal center axis of the tube which decreases in the direction towards the cover, ie towards the upper end of the tube. Again, this creates a fluid flow velocity inside the tube which increases in the direction towards the cap, ie towards the upper end of the tube. Thus, this design may enable forcing the fluid feed through the upper hole of the tube, and thus forcing the combustion flame further away from the fluid burner. Hereby, a further reduction of the temperature of the fluid burner and the risk of damage to the fluid burner can be achieved, especially when the fluid is fed through the tube at a relatively low pressure.

The fluid burner may be designed such that the outer circumference of the upper portion of the cover is larger than the inner circumference of the tube. By this, the upper part of the cap is prevented from being received in the tube, which enables a precise and safe engagement between the cap and the tube.

The fluid burner according to the invention can be used in a fluid combustion unit for burning volatile gases from a fuel tank on board a ship.

The above-discussed advantages of the different embodiments of the fluid burner according to the invention can naturally be transferred to the different embodiments of the use according to the invention.

Still other objects, features, aspects and advantages of the present invention will appear from the following embodiments and drawings.

In FIG. 1 , a fluid combustion unit 1 , more particularly a gas combustion unit, is illustrated. The fluid or gas combustion unit 1 is configured on a ship (not illustrated), more specifically on an LNG carrier, for burning volatile gas from one or more LNG tanks of the ship. The fluid combustion unit 1 includes a fluid burner system 3 , a gas supply system (not illustrated), a combustion chamber 5 and a chimney 7 . The volatilized gas from the LNG tank is fed into the fluid burner system 3 and further into the combustion chamber 5 where it is ignited and burned. Before leaving the fluid combustion unit 1 , the combustion products leave the combustion chamber 5 to mix with the cooling air in the chimney 7 . The construction and function of fluid combustion units are well known in the art and will not be described in further detail herein.

The fluid burner system 3 comprises a fluid burner 9 , more particularly a gas burner, which is further detailed in FIGS. 2 to 6 . The fluid burner 9 comprises a main body 11 which in turn comprises a hollow, elongated stainless steel tube 13 of refractory concrete and a solid cover 15 . The tube 13 and the cover 15 are discrete separable elements having a circular periphery as seen along the longitudinal central axis C of the fluid burner 9 .

The tube 13 has a wall 17 of uniform thickness along and around the longitudinal center axis C of the fluid burner 9 . Referring to FIG. 4 , it includes a lower end 19 , a lower portion 21 , an upper portion 23 and an upper end 25 arranged in sequence along the longitudinal central axis C. Referring to FIG. The upper portion 23 of the tube 13 contains a plurality of circular holes 27 extending through the wall 17 of the tube 13 . The holes 27 are equidistantly arranged in a column 29 . The rows 29 of holes 27 are parallel to each other and extend equidistantly around the longitudinal center axis C of the fluid burner 9 .

Referring to FIG. 5 , the cover 15 comprises an upper part 31 and a bottom part 33 arranged concentrically with respect to the longitudinal center axis C of the fluid burner 9 . The boundary between the upper part 31 and the bottom part 33 of the cover 15 is illustrated by dashed lines. The upper part 31 has the basic shape of a circular plate with a constant cross-section along the longitudinal central axis C. The bottom part has the basic shape of a truncated cone with a circular cross-section that decreases along the longitudinal central axis C in a direction away from the upper part 31 of the cover 15 . The maximum cross-section of the bottom part 33 is smaller than the cross-section of the upper part 31 .

As is evident from the drawings, and in particular FIG. 5 , the cap 15 closes the upper end 25 of the tube 13 . The bottom part 33 of the cover 15 has a largest circumference which is smaller than the inner circumference of the tube 13 and which is accommodated inside the tube 13 . The upper portion 31 of the cover 15 has a circumference substantially equal to the outer circumference of the tube 13 and larger than the inner circumference of the tube 13 . The upper portion 31 of the cover 15 is arranged outside the tube 13 and adjoins its annular edge delimiting the upper end 25 of the tube 13 . Due to the above specified relative dimensions of the tube 13 and the cover 15 , an annular groove 35 is formed between the bottom portion 33 of the cover 15 and the tube 13 .

5 and 6a-c, the fluid burner 9 further comprises an annular support 37 in the form of a flat circular ring of stainless steel, an annular first protrusion 39 in the form of a circular extending skirt of stainless steel, and An extremely short tube of cross-section and an annular second protrusion 41 in the form of stainless steel. The support member 37 , the first protruding portion 39 and the second protruding portion 41 are arranged concentrically with respect to the longitudinal central axis C of the fluid burner 9 . The first protruding portion 39 protrudes upwards and outwards from the outer edge of the supporting member 37 , and the second protruding portion protrudes downwards from the outer edge of the supporting member 37 . The supporting member 37 , the first protruding portion 39 and the second protruding portion 41 are integrally formed in a configuration designed to match with the main body 11 of the fluid burner 9 . More specifically, the support 37 is positioned and clamped between the tube 13 and the cover 15 with the first protrusion 39 and the second protrusion 41 protruding from the outer surface 43 of the body 11 ( FIG. 3 ). The first protrusion 39 has an annular longitudinal first edge 39a and a second edge 39b extending along each other (Fig. 6a). When the second edge 39b is free, the first protrusion 39 engages with the main body 11 indirectly, more particularly via the support 37 , at and along the first edge 39a. The second protrusion 41 has an annular longitudinal first edge 41 a and a second edge 41 b extending along each other ( FIG. 6 b ). The second protrusion 41 surrounds the main body 11 , and its interior contacts the outer surface 43 of the main body 11 between the first edge 41 a and the second edge 41 b. The tube 13 and the cover 15 are connected by means of elements not illustrated in the drawings. Thereby, the support 37 and the first 39 and second 41 protrusions are at the border 45 between the tube 13 and the cover 15 ( FIG. 5 ), ie above the uppermost row 29 a of the rows 29 of holes 27 ( FIG. 3 ) extends around the longitudinal central axis C of the fluid burner 9 . In addition, with particular reference to Figures 5 and 6c, the support 37 is clamped between the tube 13 and the cover 15, so that the first protrusion 39 protrudes obliquely at an angle α=30 degrees relative to the longitudinal central axis C of the fluid burner 9, And the second protrusion 41 protrudes downwards and protrudes from the outer surface 47 of the tube 13 so as to close the uppermost part of the tube 13 .

The fluid burner 9 is configured to transport the volatile gas to be combusted into the combustion chamber 5 of the fluid combustion unit 1 ( FIG. 1 ). More specifically, referring to FIG. 4, the volatile gas is configured to be fed into the interior 49 of the tube 13 of the fluid burner 9 via the lower end 19 of the tube 13, then upwardly through the lower portion 21 of the tube 13, and then fed into Into the upper part 23 of the tube 13 and further into the outer portion 51 of the tube 13 and thus into the combustion chamber 5 ( FIG. 1 ) via the hole 27 of the tube wall 17 . Inside the combustion chamber 5, as previously discussed, the volatile gases are ignited and burn in the form of a flame. The first protrusion 39 and the second protrusion 41 are configured to force the volatile gases and thus the combustion frame away from the body 11 of the fluid burner so that its temperature remains low enough to avoid melting damage to the tube 13 and to avoid damage to the cover 15 Fracture damage, even when the volatilization pressure and volatilization velocity through holes 27 are relatively low. The frusto-conical shape of the bottom portion 33 of the cover 15 is configured to accelerate the velocity of volatile gases through the holes 27 near the upper end 25 of the tube 13 to assist in reducing the temperature of the body 11 and thus minimize damage to the body 11 . The first protrusion 39 and the second protrusion 41 will protect and shield the main body 11 of the fluid burner 9 and will withstand harsh environments. If and when the first protrusion 39 and the second protrusion 41 are damaged, the arrangement consisting of the support 37 and the first protrusion 39 and the second protrusion 41 can be replaced by a new arrangement, while further use of the tube 13 is possible. and cover 15 .

The above specific examples of the invention should be considered as examples only. Those of ordinary skill in the art realize that the specific examples discussed can be varied in several ways without departing from the inventive concept.

As an example, a fluid burner need not include the second protrusion but may only include the first protrusion.

As another example, a fluid burner need not include supports for securing the first and possibly second protrusions to the body of the fluid burner. In fact, the first protrusion and possibly the second protrusion can be fixed directly to the body of the fluid burner.

As yet another example, the support need not be secured to the body of the fluid burner by being clamped between the tube and the cover. In an alternative embodiment of the invention, the support may be arranged with a tight fit on the outside of the tube and/or cover so as to be held in place by friction. Therefore, the first protrusion and the second protrusion do not need to be arranged at the boundary between the tube and the cap.

The first protrusion and the second protrusion do not need to be formed separately from the tube and the cover, but may be integrally formed with the tube and/or the cover. Such a design may destroy the possibility of replacing only the first and second protrusions and the support, if present, if these are damaged.

The angle α between the first protrusion and the longitudinal center axis of the fluid burner need not have the above-mentioned value, but can be larger or smaller.

The tube and cap need not be formed separately and need not be made of different materials, but could instead be integrally formed and/or made of the same material.

It should be emphasized that descriptions of details not relevant to the invention have been omitted and that the figures are only schematic and not drawn to scale. It should also be mentioned that some of the diagrams have been more simplified than others. Accordingly, some components may be illustrated in one figure but omitted in another. Finally, as used herein, the prepositions "first", "second", etc. are only used to distinguish different components and do not require relative positioning or orientation.

The invention will now be described in more detail with reference to the accompanying schematic drawings in which [FIG. 1] Schematically illustrating a cross-section of a fluid combustion unit; [Fig. 2] is a schematic perspective view of the fluid burner of the fluid combustion unit in Fig. 1; [Fig. 3] is a schematic side view of the fluid burner in Fig. 2; [Fig. 4] is a schematic cross-section of the fluid burner in Fig. 2; [Fig. 5] is an enlargement of a part of the cross-section in Fig. 4; [Fig. 6a] is a schematic side view of the configuration of the fluid burner in Fig. 2; [FIG. 6b] is a schematic top view of the configuration in FIG. 6a; and [Fig. 6c] is a schematic cross-section of the configuration in Fig. 6a.

Claims (15)

A fluid burner (9) for a fluid combustion unit (1), the fluid burner comprising a main body (11) which in turn comprises a fluid for delivering a fluid to be burned to a combustion chamber ( 5) a hollow tube (13) and a cap (15) at least partially closing an upper end (25) of the tube (13), the tube (13) further comprising a tube (13) for receiving the tube (13) At the lower end (19) of the fluid, one wall (17) of the tube (13) contains holes (27) in rows (29) surrounding the fluid burner (9) A longitudinal central axis (C) extends, wherein the holes (27) allow the fluid to be burned to flow from one of the interior (49) of the tube (13) to an exterior (51), the fluid burner ( 9) is characterized in that it further comprises an annular first protrusion (39), which extends around the longitudinal central axis (C) of the fluid burner (9) and extends from the main body (11) An outer surface (43) protrudes obliquely and away from the lower end (19) of the tube (13) over an uppermost row (29a) of holes (27) of the tube (13), wherein the first Protrusions (39) form an angle α with respect to the longitudinal central axis (C) of the fluid burner (9), where 0<α<90 degrees, the uppermost row (29a) of holes (27) being closest to The cover (15) is provided with rows of holes (27). The fluid burner (9) for a fluid combustion unit (1) as claimed in claim 1, wherein the tube (13) and the cover (15) are formed separately. The fluid burner (9) for a fluid combustion unit (1) according to claim 1 or 2, wherein the cover (15) and the tube (13) are made of different materials. The fluid burner (9) for a fluid combustion unit (1) according to any one of claims 1 to 3, wherein the first protrusion (39) is between the tube (13) and the cover (15) Protrudes from the outer surface (43) of the main body (11) at a boundary (45) between them. The fluid burner (9) for a fluid combustion unit (1) according to any one of claims 1 to 4, wherein the tube (13) and the first protrusion (39) are formed separately. A fluid burner (9) for a fluid combustion unit (1) according to any one of claims 1 to 5, wherein an upper portion (23) of the tube (13) comprising the holes (27) has A substantially uniform cross-section along the longitudinal central axis (C) of the fluid burner (9). A fluid burner (9) for a fluid combustion unit (1) according to any one of claims 1 to 6, further comprising a ring extending around the longitudinal central axis (C) of the fluid burner (9) shaped support (37), the support (37) is connected to the first protrusion (39) and engages with the main body (11) of the fluid burner (9), so that the first protrusion (39) fixed to the body (11). The fluid burner (9) for a fluid combustion unit (1) according to any one of claims 1 to 6, further comprising an annular second protrusion (41), the annular second protrusion surrounding the fluid The longitudinal center axis (C) of the burner (9) extends from the body (11) between the uppermost row (29a) of the bore (27) of the tube (13) and the first protrusion (39) ) of the outer surface (43) protrudes. The fluid burner (9) for a fluid combustion unit (1) according to claim 8, wherein the second protrusion (41) protrudes from an outer surface (47) of the tube (13). A fluid burner (9) for a fluid combustion unit (1) as claimed in claim 8 or 9, further comprising an annular support extending around the longitudinal central axis (C) of the fluid burner (9) ( 37), the support (37) is connected to the first and second protrusions (39, 41) and engages with the main body (11) of the fluid burner (9), so that the first and second Two protrusions (39, 41) are fixed to the main body (11). The fluid burner (9) for a fluid combustion unit (1) according to claim 7 or 10, wherein the support (37) is clamped between the cover (15) and the tube (13). A fluid burner (9) for a fluid combustion unit (1) according to any one of claims 1 to 11, wherein the cover (15) comprises an upper portion (31) and a bottom portion (33), wherein The bottom part (33) protrudes into the tube (13). The fluid burner head (9) for a fluid combustion unit (1) according to claim 12, wherein the bottom portion (33) includes a gradual narrowing in a direction away from the upper portion (31) of the cover (15) a part of. The fluid burner head (9) for a fluid combustion unit (1) as claimed in claim 12 or 13, wherein an outer circumference of the upper part (31) of the cover (15) is larger than an inner circumference of the tube (13) circumference. Use of a fluid burner (9) according to any one of claims 1 to 14 in a fluid combustion unit (1) for burning volatile gases from a fuel tank on a ship.

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