JP2014122632A - Fuel supply device and operation method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new fuel supply device for ship diesel combustion engines, and an operation method thereof.SOLUTION: A fuel supply device 1 includes a feeder fuel circuit 4 capable of supplying a first fuel from a first fuel tank 12 for a first fuel type, or a second fuel from a second fuel tank 13 for a second fuel type to a mixing tank 14 through a first pump device 6, and a booster fuel circuit 5 capable of supplying the fuel from the mixing tank 14 to ship diesel combustion engines 2 and 3 through a second pump device 21. In an ordinary operation mode, the first pump device 6 sucks a first supply flow of the first or second fuel from the fuel tanks 12 and 13, supplies a first partial supply flow to the mixing tank 14, and circulates a second partial supply flow in the feeder fuel circuit 4, the second pump device 21 of the booster fuel circuit 5 sucks the fuel from the mixing tank 14 with a second supply flow larger than the first supply flow, and supplies the fuel to the ship diesel combustion engines 2 and 3, and an unburnt fuel is returned to the mixing tank 14.

Description

  The invention relates to a fuel supply device for at least one marine diesel combustion engine as described in claim 1. The invention further relates to a method of operating such a fuel supply device.

  In practice, it is known that marine diesel combustion engines can be operated with various types of fuel. For example, it is possible to operate a marine diesel combustion engine on the one hand with heavy oil fuel and on the other hand with distillate fuel. Heavy oil fuels are cheaper but have a higher sulfur content, resulting in relatively higher fuel emissions. Distillate fuels emit less exhaust gas, but are more expensive. For cost reasons, marine diesel combustion engines are operated on heavy oil fuel in the open ocean. On the other hand, when the ship is operated near the shore and is operated in the so-called SECA (Sulfur Content Emission Control Zone) zone, the operation of the ship diesel combustion engine is distilled from the operation using heavy oil fuel for reasons of emission. It is necessary to switch to operation using fuel. And only if the ship diesel combustion engine meets the SECA zone emission regulations for hazardous substance emission due to the combustion of distillate fuel, the ship can enter such SECA zone.

  A fuel supply device for a marine diesel combustion engine, which can supply either heavy oil fuel or distillate fuel to the marine diesel combustion engine by the fuel supply device is practically a so-called feeder fuel circulation, And it has what is called a booster fuel circulation.

  Through the feeder fuel circulation, the first pump device can be used to supply either the first fuel or the second fuel in the direction toward the mixing tank. Fuel can be supplied from the mixing tank in the direction toward the ship diesel combustion engine or toward each ship diesel combustion engine using the second pump device of booster circulation. At this time, the first pump device for feeder fuel circulation sucks each fuel in the first supply amount flow, and the first partial supply flow rate of the first supply amount flow is supplied in the direction toward the mixing tank. Also, the second partial supply flow rate of the first supply amount flow circulates in the feeder fuel circulation. The second pump device for booster fuel circulation draws fuel from the mixing tank in a second supply flow, which is clearly greater than the first supply flow. Therefore, the fuel supplied in or through each ship diesel combustion engine is more than the fuel actually burned in or in each ship diesel combustion engine, and the extra fuel is particularly cooled. And utilized for lubrication. The fuel of the marine diesel combustion engine or not used by each combustion engine is returned to the mixing tank through the return line of the booster fuel circulation.

  When the fuel supply is switched from heavy oil fuel to distillate fuel in the feeder fuel circulation due to such different supply amounts in the feeder fuel circulation and the booster fuel circulation, the heavy oil fuel is relatively slowly in the booster fuel circulation. Replaced with distillate fuel. In the switching process from operation with heavy oil fuel to operation with distillate fuel, the amount of distillate fuel supplied from the feeder circuit into the mixing tank is only the same amount as the heavy oil fuel consumed in the booster circulation. Therefore, heavy oil fuel is diluted relatively slowly with distillate fuel in the booster fuel circulation. As a result, it takes a relatively long time for the heavy oil fuel to be sufficiently replaced by the distillate fuel in the booster circulation to meet the SECA zone emission regulations.

  For this reason, in a fuel supply device known in practice, after the fuel supply is switched from heavy oil fuel to distillate fuel in the feeder circulation, the fuel is sufficiently changed in the booster fuel circulation and discharged from the SECA zone. It may take 10 hours or more to meet the regulations.

  The object of the present invention is to provide a new fuel supply device for at least one marine diesel combustion engine and a method of operating the same.

  This problem is solved by the fuel supply device according to claim 1. According to the invention, the first pumping device for the feeder fuel circulation is switched over from the first fuel type to the second fuel type for the operation of one of the marine diesel combustion engines or the respective marine diesel combustion engine. The second fuel tank is configured so that the second fuel is sucked by the third supply amount flow larger than the first supply amount flow.

  In the present invention, the first pump device for feeder fuel circulation sucks the third supply amount flow, which is larger than the first supply amount flow in the normal operation mode, from the fuel tank for the second fuel type in the switching operation mode. It is configured. This makes it possible to replace the first fuel, in particular heavy oil fuel, with the second fuel, in particular distillate fuel, clearly and more quickly in the booster fuel circulation, so that the ship diesel combustion engine or each ship diesel combustion The engine is able to comply with SECA zone emission standards clearly and more quickly than was possible in practice. Therefore, the ship having the fuel supply device according to the present invention can enter the SECA zone more rapidly after the fuel switching from the heavy oil fuel to the distillate fuel is started in the feeder fuel circulation.

  Preferably, the first pump device for the feeder fuel circulation is configured so that the first pump device sucks the second fuel in the third supply amount flow in the switching operation mode, and the first partial supply flow rate in the third supply amount flow. Is supplied in a direction toward the mixing tank, and the first partial supply flow rate is configured to correspond to the second supply amount flow of the booster fuel circulation. Thereby, since the replacement of the first fuel type with the second fuel type in the booster fuel circulation is particularly suitable and quick, especially after the fuel supply is switched from the first fuel type to the second fuel type, The SECA zone emission regulations can be met quickly.

  According to a preferred development of the invention, a first shut-off valve / valve is installed upstream of the mixing tank in the booster fuel circulation return line, which is open in normal operating mode and closed in switching operating mode. Preferably, a fuel discharge pipe branches off from the return line upstream of the first shut-off valve / valve, and a second shut-off valve / valve is attached to the fuel discharge pipe. It is closed in the operation mode and opened in the switching operation mode.

  With these two shut-off valves, in the switching operation mode, the first fuel in the booster fuel circulation is quickly discharged from the booster fuel circulation after the feeder fuel circulation is switched to the third supply flow, so that the booster fuel It is particularly possible for the first fuel to be quickly replaced by the second fuel in the circulation.

  A method of operating such a fuel supply device according to the invention is defined in claim 7.

  Preferred developments of the invention can be seen from the dependent claims and the following description. Embodiments of the present invention will be described in detail with reference to the drawings, but are not limited thereto.

1 is a diagrammatic representation of a fuel supply device according to the invention for at least one marine diesel combustion engine. FIG.

  The present invention relates to a fuel supply device for at least one ship diesel combustion engine of a ship and a method for operating such a fuel supply apparatus.

  FIG. 1 is a diagram schematically showing a fuel supply device 1, and in the illustrated embodiment, the fuel supply device 1 supplies fuel to two marine diesel combustion engines 2 and 3. The fuel supply apparatus 1 can also supply fuel to only one marine diesel combustion engine or to three or more marine diesel combustion engines, unlike the illustrated embodiment.

  The fuel supply device 1 has a feeder fuel circulation 4 and a booster fuel circulation 5.

  The feeder fuel circulation 4 has a first pump device 6, and in the illustrated embodiment, this first pump device 6 comprises two fuel pumps 7 and 8 provided in parallel. In the embodiment shown, the two pumps 7 and 8 are each preceded by a shut-off valve 9 or 10. It should be pointed out that the first pump device 6 can have only one fuel pump or three or more fuel pumps provided in parallel, instead of the two fuel pumps 7 and 8.

  Depending on the switch position of the valve 11 by the first pump device 6 of the feeder fuel circulation 4, the first fuel tank 12, from the first fuel, that is, heavy oil fuel in the illustrated embodiment, or the second fuel tank 13 The second fuel, that is, the distillate fuel in the illustrated embodiment, can be sucked, and the fuel sucked by the first pump device 6 of the feeder fuel circulation 4 can be supplied in the direction toward the mixing tank 14.

  In the normal operation mode of the fuel supply device 1, the first pump device 6 of the feeder fuel circulation 4 draws the appropriate fuel from one of the two fuel tanks 12 or 13 with a defined first supply flow rate, At this time, the first partial supply flow in the first supply flow can be supplied in the direction toward the mixing tank 14, and the second partial supply flow in the first supply flow is It is circulated in the feeder fuel circulation 4 through a circulation pipe 15 in which a pressure safety valve 16 is incorporated.

  When the marine diesel combustion engines 2 and 3 are operated at full load and the fuel is used 100% in total, the first supply amount flow drawn from either one of the two fuel tanks 12 or 13 by the pump device 6 is Typically, this fuel consumption is 160%, in which case the first partial supply flow rate supplied in the direction toward the mixing tank 14 is 100%, and the second partial supply flow rate introduced through the circulation pipe 15 Is 60%.

  A first partial supply flow rate of the first supply amount flow supplied in the direction toward the mixing tank 14 through the first pump device 6 of the feeder fuel circulation 4 is placed in front of the flow rate measurement device 17 in FIG. When the valve 18 is open, it is guided through the flow measuring device 17.

  Alternatively, for example, if the flow measuring device 17 is faulty, the first partial supply flow of the first supply flow can bypass the flow measuring device 17 through the bypass pipe 19, The valve 18 is closed and the valve 20 incorporated in the bypass pipe 19 is opened.

  It is pointed out here that the second partial supply flow of the first supply flow that circulates in the feeder fuel circulation 4 through the circulation pipe 15 is supplied to the mixing tank 14 by the pressure safety valve 16. The first partial supply flow rate is set to constitute a constant pressure level. This pressure level can be, for example, 7 bar.

  When heavy oil fuel is supplied as the first fuel type from the first fuel tank 12 through the feeder fuel circulation 4 in the direction toward the mixing tank 14, the heavy oil fuel is preheated in the first fuel tank 12, The temperature of the heavy oil fuel in the first partial supply flow supplied to the mixing tank 14 is typically about 90 ° C.

  The booster circulation 5 has a second pump device 21, and the second pump device 21 can suck fuel from the mixing tank 14, and the ship diesel combustion engine 2, 3 or each ship diesel combustion engine. It is possible to supply in a direction toward two or three. A portion of the booster fuel circulation 5 through which fuel can be supplied from the mixing tank 14 to one of the marine diesel combustion engines 2, 3 or each of the marine diesel combustion engines 2, 3 is the booster fuel circulation. Also referred to as five feed lines 22. Fuel supplied in a direction toward one of the marine diesel combustion engines 2 and 3 or each of the marine diesel combustion engines 2 and 3 through the feed line 22, and either one of the marine diesel combustion engines 2 and 3 or each marine diesel combustion engine 2. What has not been burned in 3 can be returned to the mixing tank 14 through the return line 23 of the booster fuel circulation 5.

  As can be seen from FIG. 1, the fuel drawn from the mixing tank 14 through the second pump device 21 of the booster fuel circulation 5 is heavy oil fuel in each of the marine diesel combustion engines 2 and 3 or marine diesel combustion engines 2 and 3. When operated, it can be supplied through the preheater 24. When the marine diesel combustion engine 2 or 3 or each marine diesel combustion engine 2 or 3 is operated with distillate fuel, the valve 25 placed in front of the preheating device 24 is closed and the valve 27 is opened. Distilled fuel is guided through the bypass pipe 26. A viscosity measuring device 28 is incorporated in the feed line 22 of the booster fuel circulation 5 downstream of the preheating device 24, and this viscosity measuring device 28 is used when the heavy oil fuel is guided through the preheating device 24. The operation of the preheating device 24 is controlled to affect the viscosity of the heavy oil fuel through.

  Typically, heavy oil fuel is heated by the preheating device 24 to set the viscosity to 12-14 cSt (Stoke), and the pressure level of the booster fuel circulation 5 is, for example, 12 bar downstream of the second pump device 21. Can do.

  As already mentioned, the second pump device 21 of the booster fuel circulation 5 sucks fuel from the mixing tank 14 and goes in the direction toward the ship diesel combustion engine 2, 3 or each ship diesel combustion engine 2, 3, ie, the ship. This fuel is supplied in accordance with the open / closed state of the valves 29 and 30 placed in front of the diesel combustion engines 2 and 3. The second pump device 21 of the booster fuel circulation 5 draws fuel from the mixing tank 14 in a second supply amount flow, which is clearly higher than the first supply amount flow of the feeder fuel circulation 4.

  Therefore, in a specific embodiment, when the first supply amount flow of the feeder fuel circulation 4 is 160%, the second supply amount flow of the booster fuel circulation 5 is set to 300%. If both valves 29, 30 are open, a partial supply flow of 150% is guided through each marine diesel combustion engine 2, 3 respectively.

  However, even when both marine diesel combustion engines 2 and 3 are combined, a maximum of 100% of fuel can be burned at full load, that is, each marine diesel combustion engine 2 and 3 can individually burn up to 50% each. It is. As a result, both marine diesel combustion engines 2, 3 are supplying more fuel than can be combusted therein, and this surplus fuel is used for cooling and lubrication and goes to the mixing tank 14 through the return line 23. You can return to the direction.

  When one of the two valves 29, 30 is closed, that is, when one of the two marine diesel combustion engines 2, 3 is disconnected from the feed line 22 of the booster fuel circulation 5, it is disconnected. The fuel that cannot be supplied through the marine diesel combustion engine 2, 3 bypasses the other marine diesel combustion engine 3, 2 through the bypass pipe 31, and at this time, the bypass valve 32 incorporated in the bypass pipe 31 is opened.

  The fuel that can be returned to the mixing tank 14 through the return line 23 of the booster fuel circulation 5 is guided through the cooling device 34 or through the bypass pipe 35 depending on the state of the valve 33 incorporated in the return line 23. be able to.

  When heavy oil fuel is burned as fuel in the marine diesel combustion engine 2, 3 or in each marine diesel combustion engine 2, 3, excess heavy fuel fuel that has not been burned is bypassed the cooling device 34 through the bypass pipe 35. The When distillate fuel is burned as fuel in the marine diesel combustion engine 2 or 3 or in each marine diesel combustion engine 2 or 3, excess distillate fuel that has not been burned is cooled according to its temperature. 34 through.

  In the embodiment illustrated in FIG. 1, coarse impurities are filtered from the fuel supplied in the booster fuel circulation 5, thereby protecting the marine diesel combustion engine 2, 3 or each marine diesel combustion engine 2, 3 from damage. For this purpose, each combustion engine 2, 3 is provided with a coarse filter 36, 37 downstream of the respective valves 29, 30.

  It is proposed in the present invention from the first fuel, that is, the heavy oil fuel, to the second fuel, that is, the distillate fuel, for the operation of the ship diesel combustion engine 2, 3 or each ship diesel combustion engine 2, 3. In the switching operation mode in which the first supply is switched, the first pump device 6 no longer draws the second fuel from the second fuel tank 13 in the first supply amount flow, but in the third supply larger than the first supply amount flow. The first pump device 6 of the feeder fuel circulation 4 is configured so as to be sucked in a mass flow.

  In a preferred embodiment of the present invention, the first pump device 6 of the feeder fuel circulation 4 is configured such that the first pump device 6 sucks the second fuel from the second fuel tank 13 in the switching operation mode in the third supply amount flow. In addition, the first partial supply flow rate of the third supply amount flow supplied in the direction toward the mixing tank 14 is the second supply amount flow of the booster fuel circulation 5, that is, the second pump device of the booster fuel circulation. It is configured to be larger or the same as compared to the 21 feed flow.

  In a specific embodiment, in the switching operation mode, the first partial supply flow rate of the third supply amount flow supplied in the direction from the pump device 6 of the feeder fuel circulation 4 toward the mixing tank 14 is 300%, In other words, this corresponds to the second supply amount flow of the booster fuel circulation 5.

  At this time, 160% of the second fuel is sucked from the second fuel tank 13 through each of the two pumps 7 and 8 of the pump device 6 of the feeder fuel circulation 4, 300% is supplied to the mixing tank 14, and the remaining 20 % Can be circulated in the feeder fuel circulation 4 through the circulation pipe 15.

  A first shut-off valve 38 is installed in the return line 23 of the booster fuel circulation 5 upstream of the mixing tank 14 and is opened in the normal operation mode and closed in the switching operation mode. A fuel discharge line 39 is branched from the return line 23 of the booster fuel circulation 5 upstream of the first shut-off valve 38. The fuel discharge line 39 is a first fuel tank for heavy oil fuel in the illustrated embodiment. 12 is open. The fuel discharge line 39 is provided with a second shut-off valve 40, which is closed in the normal operation mode and opened in the switching operation mode.

  Therefore, according to the present invention, when the fuel supply is switched from heavy oil fuel to distillate fuel, it is possible to increase the pumping capacity of the first pump device 6 of the feeder fuel circulation 4, thereby remaining in the booster fuel circulation 5. The heavy fuel oil is quickly removed from the booster fuel circulation 5 and the heavy oil fuel is quickly replaced with distillate fuel. Therefore, after the pumping capacity of the first pump device 6 in the feeder fuel circulation 4 is enhanced, the second shut-off valve 40 is first opened and then the first shut-off valve 38 is closed.

  After being switched to the switching operation mode, the first pumping device 6 of the feeder fuel circulation 4 is preferably operated with an increased pumping capacity for a defined time or until a defined flow rate, whereby The switching operation mode is active for a defined time or until a defined flow rate is reached.

  After this time has elapsed or when this flow rate has been reached, it returns to the normal operating mode, in which both shut-off valves 38 and 40 are first controlled, i.e. the first shut-off valve 38 is opened and the second The shut-off valve 40 is closed, thereby reducing the pumping capacity of the first pump device 6 in the feeder fuel circulation 4, i.e. from the third supply flow, the respective fuel tanks by the first pump device 6 in the normal operation mode. 12, 13 to the first supply flow that is sucked.

  Therefore, according to the present invention, when switching from the heavy oil fuel supply to the distillate fuel supply, the heavy oil fuel in the booster fuel circulation 5 is quickly removed from the booster fuel circulation 5 and quickly replaced with the distillate fuel. After the supply is switched to the distillate fuel supply, the vessel can enter the SECA zone in a short time.

  According to a preferred development of the invention, a control valve 41 is mounted in parallel with the second shut-off valve 40. The control valve 41 can be controlled according to the measurement signal of the flow rate measuring device 17. The control valve 41 causes a relatively small amount of fuel to be burned by the marine diesel combustion engine 2, 3 or each marine diesel combustion engine 2, 3, and for that reason, fuel supplied from the feeder fuel circulation 4 to the mixing tank 14. Is relatively small, by opening the control valve 41 correspondingly, it becomes possible to discharge the fuel in the direction from the return line 23 toward the fuel discharge line 39, and thereby in the booster fuel circulation 5. A constant consumption in the booster fuel circulation 5 is set irrespective of the actual fuel consumption of the marine diesel combustion engine 2, 3 or of each marine diesel combustion engine 2, 3, so that through the feeder fuel circulation 4 A certain amount of fuel is supplied to the mixing tank 14.

  This is particularly advantageous when the booster fuel circulation 5 of the fuel supply device 1 is increased before the pumping capacity of the first pump device 6 of the feeder fuel circulation 4 is increased when switching from the normal operation mode to the switching operation mode. This is a case where the temperature inside needs to be lowered.

  As described above, the temperature level in the booster fuel circulation 5 in the heavy oil fuel operation is approximately 140 ° C. However, the temperature level in the booster fuel circulation needs to be reduced to approximately 45 ° C. before switching to distillate fuel operation.

  The length of time required for such a cooling process varies in practice depending on the actual fuel consumption of the marine diesel combustion engines 2, 3 or of each marine diesel combustion engine 2, 3. By controlling the control valve 41 according to the measurement signal of the flow rate measuring device 17, this cooling process is related to the actual consumption of the ship diesel combustion engine 2, 3 or each ship diesel combustion engine 2, 3. It can be configured without. As a result, the point in time at which switching to distillate fuel operation becomes possible has nothing to do with the actual consumption of the marine diesel combustion engines 2, 3 or the marine diesel combustion engines 2, 3.

  By opening the control valve 41, a constant high fuel consumption of the marine diesel combustion engine 2, 3 or of each marine diesel combustion engine 2, 3 can be simulated, whereby a constant delivery through the pump device 6 An amount is supplied to the mixing tank 14. That is, when the measurement signal of the flow rate measuring device 17 indicates that the consumption amount of the ship diesel combustion engine 2, 3 or each ship diesel combustion engine 2, 3 is relatively small, the control valve 41 is further opened, On the other hand, when the measurement signal of the flow rate measuring device 17 indicates that the consumption of the marine diesel combustion engine 2, 3 or the marine diesel combustion engine 2, 3 is relatively high, the control valve 41 is further closed. It is done.

  Desirably, control of the control valve 41 according to the measurement signal of the flow measurement device 17 is performed by comparing the measurement signal of the flow measurement device 17 with a reference value. If the measurement signal of the flow measuring device 17 is greater than or corresponds to the reference value, the actual consumption of the ship diesel combustion engine 2, 3 or of each ship diesel combustion engine 2, 3 will be correspondingly high. Thus, the control valve 41 is closed. On the other hand, when the measurement signal of the flow rate measuring device 17 is smaller than the reference value, the actual consumption of the ship diesel combustion engine 2, 3 or each ship diesel combustion engine 2, 3 is lower, and the control The valve 41 is opened according to the difference between the reference value of the measurement signal and the actual measurement value, whereby a constant consumption is simulated and a constant fuel flow rate is supplied to the mixing tank 14 through the feeder fuel circulation 4. As a result, the temperature level in the booster fuel circulation 5 decreases quickly and irrespective of the load.

DESCRIPTION OF SYMBOLS 1 Feeder fuel circulation 2 Ship diesel combustion engine 3 Ship diesel combustion engine 4 Feeder fuel circulation 5 Booster fuel circulation 6 Pump apparatus 7 Fuel pump 8 Fuel pump 9 Shutoff valve 10 Shutoff valve 11 Valve 12 Fuel tank Heavy oil 13 Fuel tank Distillation DESCRIPTION OF SYMBOLS 14 Mixing tank 15 Circulation pipe 16 Pressure safety valve 17 Flow rate measuring device 18 Valve 19 Bypass pipe 20 Valve 21 Pump device 22 Feed line 23 Return line 24 Preheating device 25 Valve 26 Bypass pipe 27 Valve 28 Viscosity measuring device 29 Valve 30 Valve 31 Bypass Pipe 32 Bypass valve 33 Valve 34 Cooling device 35 Bypass pipe 36 Coarse filter 37 Coarse filter 38 Shutoff valve / valve 39 Fuel discharge pipe 40 Shutoff valve Valve 41 control valve

Claims (9)

A fuel supply device (1), comprising a feeder fuel circulation (4), and through the first pump device (6) by the feeder fuel circulation (4), a first fuel tank (12) for a first fuel type To the first fuel, in particular heavy oil fuel, or from the second fuel tank (13) for the second fuel type, the second fuel, in particular distillate fuel, can be supplied in the direction toward the mixing tank (14), and The fuel supply device (1) comprises a booster fuel circulation (5) through which the fuel is fed from the mixing tank (14) through the second pump device (21) by at least one marine diesel. In the normal operation mode, the first pump device (6) of the feeder fuel circulation (4) can supply the first fuel or the second fuel. One supply flow is sucked from the respective fuel tanks (12, 13), a first partial supply flow of the first supply flow is supplied in a direction toward the mixing tank (14), and the first The second partial supply flow of one supply flow is circulated in the feeder fuel circulation (4), and the second pump device (21) of the booster fuel circulation (5) in the normal operation mode is Fuel is drawn from the mixing tank (14) and supplied in a direction toward the marine diesel combustion engine 2, 3 or each marine diesel combustion engine (2, 3) with a second feed rate flow that is greater than the first feed rate flow. In the fuel supply device (1), the fuel that has not been burned in the marine diesel combustion engine 2, 3 or each marine diesel combustion engine (2, 3) is returned to the mixing tank (14).
The first pump device (6) switches from the first fuel type to the second fuel type for operation of the marine diesel combustion engine (2, 3) or each marine diesel combustion engine (2, 3). The second fuel is sucked from the second fuel tank (13) in a third supply amount flow, and the third supply amount flow is larger than the first supply amount flow. A fuel supply device, characterized in that the first pump device (6) for fuel circulation (4) is constructed.   In the switching operation mode, the first pump device (6) sucks the second fuel in the third supply amount flow, and the first partial supply flow rate of the third supply amount flow is directed to the mixing tank (14). The first pump device (6) of the feeder fuel circulation (4) is configured so that the first partial supply flow rate corresponds to the second supply amount flow of the booster fuel circulation (5). The fuel supply device according to claim 1, wherein:   A first shut-off valve / valve (38) is mounted upstream of the mixing tank (14) in the return line (23) of the booster fuel circulation (5). The first shut-off valve / valve (38) The fuel supply device according to claim 1 or 2, wherein the fuel supply device is opened in a normal operation mode and closed in a switching operation mode.   A fuel discharge pipe (39) branches from the return line (23) upstream of the first shut-off valve / valve (38), and a second shut-off valve / valve (40) is provided in the fuel discharge pipe (39). The fuel supply device according to claim 3, wherein the second shut-off valve / valve (40) is closed in the normal operation mode and opened in the switching operation mode.   The fuel supply device according to claim 4, wherein the fuel discharge pipe (39) communicates with the first fuel tank (12).   A control valve (41) is attached in parallel to the second shutoff valve / valve (40), and the control valve (41) is a flow measuring device (4) in the feeder fuel circulation (4) in the switching operation mode. The fuel supply device according to claim 4, wherein the fuel supply device can be controlled according to the measurement signal of 17).   The method for operating the fuel supply device according to any one of claims 1 to 6, wherein the first pump device of the feeder fuel circulation (4) is first switched to switch from the normal operation mode to the switching operation mode. (6) is switched from the first supply flow to the third supply flow, then the second shut-off valve / valve (40) is opened and the first shut-off valve / valve (38) is opened. A method characterized in that is closed.   In order to switch from the switching operation mode to the normal operation mode, the first shut-off valve / valve (38) is first opened, the second shut-off valve / valve (40) is closed, and then the feeder fuel circulation is performed. 8. Method according to claim 7, characterized in that the first pump device (6) of (4) is switched from the third supply flow to the first supply flow.   After switching from the normal operation mode to the switching operation mode, the switching operation mode operates for a defined time or until the defined flow rate is reached, and after the time has elapsed or after reaching the flow rate, the normal operation is performed. 8. A method according to claim 7, characterized in that it is returned to mode.

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