JP3118595U - Liquefied gas tanker with combustor unit for burning vaporized gas - Google Patents

Abstract

Vaporized gas is burned safely and cost-effectively on a liquefied gas tanker.
A combustor unit includes a vortex combustor with a burner head that tapers conically toward an inner diameter d of the outlet, an inner diameter equal to the inner diameter d of the outlet, and at least 20 of the inner diameter d of the outlet. A cylindrical stabilization zone 48 adjacent to the burner head 46 with a length l of% and a ratio L / D of the length L to the larger inner diameter D of at least 0.33 so that the stabilization zone 48 A pre-combustion chamber 50 adjacent to the pre-combustion chamber 50 having an inner diameter larger than the inner diameter D of the pre-combustion chamber 50 and a length larger than the inner diameter D. Mixing means comprising a frustoconical outlet region 62 having a number of exhaust holes 64 for generating independent exhaust gas jets and a supply pipe 32 for mixing air concentrically surrounding the outlet region 62; Have.
[Selection] Figure 3

Description

  The present invention relates to a liquefied gas tanker equipped with a combustor unit for burning vaporized gas generated in either a liquefied gas tanker or a liquefied gas cargo ship for technical reasons.

  Because the heat insulation of the liquefied gas tank on the liquefied gas tanker is limited and the pressure resistance is also limited, various kinds of liquefied gases such as natural gas, methane, hydrogen, butane,. It is necessary to safely process gas that is constantly vaporized in various amounts from (liquefied gas). It is clear that the main solution here is to consume this gas directly on the tanker for propulsion and other applications. In known liquefied gas tankers, gas engines developed specifically for this purpose are used. However, since the engine is not operating regularly (such as a berthing period at the port), this application alone is not sufficient and re-liquefaction or combustion of the vaporized gas has been required as a possibility for further processing. . In order to maintain safety in the event of a failure, a margin is necessary, and the dedicated reliquefaction of the generated gas is extremely costly, so in principle it can be used for propulsion additionally or exclusively. Regulations stipulate that non-combustible gases must be disposed of by combustion.

  With regard to the combustion of the vaporized gas, for safety reasons it must be ensured that the generated exhaust gas does not exceed a certain temperature, which is currently specified at a maximum of 450 ° C. A considerable amount of vaporized gas is released when the propulsion unit is stopped, and the relatively low final temperature of 450 ° C. must be mixed with a large amount of air during or after combustion, and this mixing It is technically impossible to achieve this easily, since a single line of hot gas must be removed from the chimney.

  It is also required that the generated vapor must be burned with flames that are exhausted far above the ship's deck, so that the freely generated flames are in the vicinity of any part of the ship's superstructure. However, this is not preferred because it cannot be completely ruled out when there is wind, so this solution must be considered unsatisfactory from a safety standpoint.

  The purpose of the present invention is to provide a solution for burning vaporized gas safely and cost-acceptably on a liquefied gas tanker so that there is a large amount of excess air. Even a safe and complete combustion of the vaporized gas using a stable flame is guaranteed.

  A combustor unit for combusting vaporized gas, the combustor unit comprising a vortex combustion chamber having a gas supply device for vaporized gas and a supply device for combustion air, and combustion air for the gas A liquefied gas tanker comprising a combustion chamber for complete combustion and a mixing means for mixing exhaust gas generated from the combustion chamber with mixing air. A burner head tapered in a conical manner toward the zone and the inner diameter of the outlet, and a cylindrical stabilization zone adjacent to the burner head, the inner diameter of the stabilization zone being equal to the inner diameter of the outlet; And its length is at least 20% of the inner diameter of the outlet, and the stabilization zone has a larger inner diameter with a ratio L / D of length to inner diameter of at least 0.33. A cylindrical pre-combustion chamber is adjacent to the pre-combustion chamber, a post-combustion chamber having an inner diameter larger than the inner diameter of the pre-combustion chamber and a length larger than the inner diameter is adjacent to the pre-combustion chamber. By providing a frustoconical exit area with a number of exhaust holes for generating a number of independent exhaust gas jets and a supply pipe for mixing air concentrically surrounding the exit area The above object is achieved.

  This combination of measures creates a fluid technical effect, creating a very compact flame that burns stably and reliably even with a large amount of excess air, and the flue gas is effectively mixed into the mixing air. As a result, the exhaust gas is not mixed with the high-temperature gas, and the temperature of the exhaust gas can be easily controlled.

  The length of the stabilization zone is 25% or 30% or 40% of the inner diameter of the outlet or a value between these numbers.

  The pre-combustion chamber ratio L / D can be at least 0.5 or 0.75 or 1.0 or 1.25.

  Furthermore, in order to better mix the flue gas into the mixing air, a vortex generator can be provided for imparting a swirling motion to the supplied mixing air.

  In the present invention, a supply pipe for mixing air is provided concentrically around the combustion chamber.

  The frustoconical exit region of the mixing means preferably has a cone half angle of about 30 degrees with respect to the longitudinal axis of the combustion chamber.

  Further advantages and features of the present invention will become apparent from the description of preferred embodiments with reference to the drawings.

  FIG. 1 schematically shows the arrangement of the combustor unit 10 shown in FIGS. 2 and 3 in a chimney structure 12 of a liquefied gas tanker 14, and an exhaust line, that is, a gas engine of the tanker 14, is disposed inside the chimney structure 12. Since there are 16 chimneys, the combustor unit can be integrated with the existing or any other chimney structure that must be provided.

  The combustion gas in the form of vaporized gas is supplied to the combustor unit 10 through a supply line 20 that communicates with the liquefied gas tank of the ship and the safety device / control unit 22. The safety device / control unit 22 controls the safety device, the shutoff valve, and the combustion gas permanently vaporized from the tank so that the pressure in the supply line 20 is at a certain pressure (in principle, less than 200 mbar (200 hPa)). And a pressure controller for supplying the combustor unit in a controlled manner.

  2 and 3 relate to the combustor unit 10 used in the present invention. FIG. 2 is a side view, and FIG. 3 is a side view with a part in cross section.

  This combustor unit is vertically mounted on the mounting frame 26 so that the generated exhaust gas is released upwardly into the atmosphere. A vortex combustor 28 operates in a combustion chamber 30 surrounded by a supply pipe 32 for the mixing air that forms the outer jacket. Two axial fans 36 carry the mixing air into an annular region 38 between the combustion chamber 30 and the supply pipe 32 for the mixing air, and as shown in FIG. The respective air intakes are arranged in the tangential direction, and as a result, a swirling motion is generated in the supplied mixing air, and the mixed state with the exhaust gas supplied further downstream is improved.

  The combustion air fan 40 conveys combustion air into the vortex combustor 28, and combustion gas is supplied to the vortex combustor 28 through a gas pipe 42 by a control unit (not shown).

  The vortex combustor 28 includes a burner head 46 that is tapered in a conical shape toward an outlet having an inner diameter d, and the swirling combustion air passes through the burner head 46, and the vortex motion is urged. Adjacent to the burner head 46 is a cylindrical stabilization zone 48 which has an inner diameter equal to the inner diameter d of the outlet of the burner head 46 and a length l which is about 20% of the inner diameter. Have. This stabilization zone 48 is lined with refractory to help improve flame stability. Adjacent to the stabilization zone 48 is a cylindrical pre-combustion chamber 50 having a larger inner diameter D. In the present embodiment, the length L of the precombustion chamber 50 is substantially equal to the inner diameter D thereof.

  An additional air supply line leads from the combustion air fan 40 via the connection 56 to the annular space 58 and optionally the stabilization zone 48 tangentially into the precombustion chamber 50. And a plurality of orifices opening in the radial direction and / or a function of supplying the mixing air into the combustion chamber through the plurality of orifices opening radially in the post-combustion chamber 60 downstream of the pre-combustion chamber 50.

  The cylindrical post-combustion chamber 60 has a larger inner diameter than the pre-combustion chamber 50 and terminates in a frustoconical exit region 62 having a number of exhaust holes 64 on the slope.

  The post-combustion chamber 60 and the outlet region 62 are preferably made of a heat resistant stainless steel plate, but may be formed of other materials having a heat resistant lining. The end of the outlet region 62 that is substantially perpendicular to the longitudinal axis 66 of the combustor unit is closed by an end wall 68 that is perpendicular to the longitudinal axis 66.

  The supply pipe 32 for the mixing air forms an annular region 38 in the form of a concentric annular gap with the combustion chamber, and the mixing air is in the annular region 38 until it joins the jet of exhaust gas generated from the exhaust holes 64. After being guided through and mixed with the exhaust gas, it is discharged in the form of cooled exhaust gas from the converging / diverging end at the top of the supply pipe 32 for mixing air.

The gas is almost completely burned in the precombustion chamber 50 at a temperature of about 1200 ° C. with an air ratio of 2 or more. Complete combustion without soot occurs in the post-combustion chamber 60. Since the exhaust gas generated from the post-combustion chamber 60 through the exhaust holes 64 is branched into a large number of independent jets, strong mixing occurs within a very short distance. As a result, the mixing air and the exhaust gas are mixed. The body reaches an average temperature of, for example, less than 450 ° C. after a short distance, allowing the height of the chimney above the exhaust hole 64 to be kept low, via a number of independent jets that eject the exhaust gas into the mixing air. Effective mixing allows the pressure level of the mixing air to be relatively low, so an axial fan is used for the majority of the air to be supplied (mixing air) This can allow a significant reduction in power for the fan and thus save power costs. In addition, the axial fan is relatively compact and requires less installation space. With a particularly efficient configuration of the combustion chamber as a vortex combustor, the present invention can obtain substantial benefits in relation to space and safety standpoints in liquefied gas tankers.

  FIG. 4 is interposed with a closed loop pipeline 80 having an inlet 81 located outside the supply pipe 32 for mixing with air and connected to a gas pipe 42 for vaporized gas (connection not shown). 6 shows a variation of a combustor unit with a combustor failure control valve (not shown). A number of mixing lines 82 extend radially inward from the closed loop pipeline 80 and terminate inside the supply pipe for the mixing air 32 and mix vaporized gas if the combustor fails. It has the function of mixing in the working air. In this case, the vaporized gas to be combusted, if normal, is mixed with the mixing air cold enough to be no longer ignitable, only a short distance downstream of the closed loop pipeline or downstream of the exhaust hole 64. Is guaranteed. With this safety measure, even if the combustor fails, the vaporized gas is released to the port or other safe area in an unburned state without causing any disturbance, and for some reason the combustor is restarted Making it impossible to do.

  The closed loop pipeline 80 is preferably arranged outside the supply pipe 32 for mixing air as shown in the figure, but in this case, no special temperature resistance is required, so It may be arranged either inside or outside.

It is the schematic of the liquefied gas tanker by this invention provided with the combustor unit. It is a side view of a combustor unit. FIG. 3 is a side view, partly in section, of the combustor unit of FIG. 2. It is a perspective view which shows the deformation | transformation of the combustor unit provided with the closed loop pipeline for mixing vaporized gas with low temperature mixing air.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Combustor unit 12 Chimney structure 14 Liquefied gas tanker 20 Supply line 22 Control unit 26 Mounting frame 28 Eddy current combustor 30 Combustion chamber 32 Mixing air supply pipe 36 Axial flow fan 38 Annular region 40 Combustion air fan 42 Gas pipe 46 Burner Head 48 Stabilization zone 50 Precombustion chamber 56 Connection portion 58 Annular space 60 Rear combustion chamber 62 Outlet region 64 Exhaust hole 66 Vertical axis 68 End wall 70 Upper end of supply pipe 80 Closed loop pipeline 81 Inlet 82 Mixing line d Stabilization zone Inner diameter l Stabilization zone length L Precombustion chamber length D Precombustion chamber inner diameter

Claims (8)

A combustor unit (10) for combusting vaporized gas, the combustor unit (10) comprising:
A vortex combustor (28) comprising a gas supply device (42) for vaporized gas and a supply means (40) for combustion air;
A combustion chamber (30) for completely burning the gas together with combustion air;
In a liquefied gas tanker (14) having mixing means (32, 64) for mixing exhaust gas generated from the combustion chamber (30) with mixing air,
The vortex combustor (28) comprises a burner head (46) tapered conically towards the inner diameter (d) of the outlet;
Adjacent to the burner head (46) is a cylindrical stabilization zone (48) having an inner diameter equal to the inner diameter (d) of the outlet and a length (l) of at least 20% of the inner diameter (d) of the outlet. ,
A cylindrical pre-combustion chamber (50) having a larger inner diameter (D) with a ratio L / D of length (L) to inner diameter (D) of at least 0.33 directly into the stabilization zone (48). Adjacent,
A post-combustion chamber (60) having an inner diameter greater than the inner diameter (D) of the pre-combustion chamber (50) and a length greater than the inner diameter is adjacent to the pre-combustion chamber (50);
The mixing means comprises a frustoconical exit region (62) with a number of exhaust holes (64) for generating a number of independent exhaust gas jets, and concentrically surrounding the exit region (62); A liquefied gas tanker comprising a supply pipe (32) for working air.   A liquefied gas tanker according to claim 1, characterized in that the length (l) of the stabilization zone (48) is 25%, 30% or 40% of the inner diameter (d) of the outlet.   The liquefied gas tanker according to claim 1 or 2, wherein the ratio L / D is at least 0.5, 0.75, 1.0, or 1.25.   The liquefied gas tanker according to any one of claims 1 to 3, further comprising a vortex generator for imparting a swirl motion to the supplied mixing air.   The liquefied gas tanker according to any one of claims 1 to 4, characterized in that a supply pipe (32) for the mixing air is arranged concentrically around the combustion chamber (30).   The frustoconical exit region (62) of the mixing means has a conical half angle of about 30 degrees with respect to the longitudinal axis (66) of the combustion chamber (30). The liquefied gas tanker described.   A closed loop pipeline (80) for mixing air with the vaporized gas in the event of a failure of the combustor is disposed in the region of the mixing means (32, 64) and radially inward from the closed loop pipeline (80). A liquefied gas tanker according to any one of the preceding claims, characterized in that a plurality of mixing lines (82) extend and terminate in the mixing means (32, 64).   The liquefied gas tanker according to claim 7, characterized in that the closed-loop pipeline (80) is arranged inside or outside the supply pipe (32) for the mixing air.

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