KRAFTWERK

Description

[0001] The invention relates to a power plant comprising a combustion plant, a turbine generator, a lubrication circuit, and a heat exchanger. According to a second aspect, the invention relates to a method for operating a power plant.

[0002] A variety of power plants with an incinerator and a turbine are known from the prior art. In an incinerator, steam is generated, which drives the turbine. A generator converts the kinetic energy of the turbine into electrical energy. This electrical energy is either used directly or fed into the public power grid. Moving parts of the turbine, the generator, and / or any gearbox are lubricated and cooled by oil. The oil circulates in a lubrication circuit, which contains an oil / water heat exchanger through which cooling water flows. The oil / water heat exchanger serves to cool the oil in the lubrication circuit. The cooling water circulates in a cooling circuit, which contains a water / air heat exchanger, which is designed, for example, as a table cooler.To ensure adequate cooling of the cooling water, fans are used to direct air onto the table cooler. Operating these fans results in high energy consumption and high noise emissions from the power plant.

[0003] Document US3938934A discloses a system for preheating air in a combustion plant, wherein the supply air is heated by heat exchange with hot water. Documents US2017 / 074164A1 and US2005 / 039433A1 each disclose a turbo set with a lubrication circuit and a heat exchanger for cooling a cooling fluid.

[0004] The object of the invention is to avoid or reduce disadvantages of the prior art.

[0005] The invention solves this problem by a power plant with (a) a combustion plant with (i) a combustion chamber for generating steam and (ii) an air supply line for supplying air into the combustion chamber, (b) a turbo set with (i) a turbine with a rotor and (ii) a generator, (c) a lubrication circuit for lubricating and cooling the turbo set, wherein a cooling fluid circulates in the lubrication circuit, and (d) a heat exchanger for cooling the cooling fluid, which is characterized in that (e) the heat exchanger is arranged to heat the supply air.

[0006] A fuel is burned in the combustion chamber. During combustion, supply air is preferably continuously fed into the combustion chamber. A liquid line runs at least partially through the combustion chamber. A liquid conveyed in the liquid line is heated as it passes through the combustion chamber and evaporates to steam. The liquid is in particular water. The steam is conveyed to the turbine via the liquid line, where it drives the turbine rotor, setting it in rotation. The generator converts the kinetic energy of the turbine rotor or the kinetic energy of another rotor, which is connected to the turbine rotor, for example, via a gear, into electrical energy. The cooling fluid in the lubrication circuit is heated by the movement of the turbine rotor and / or by the movement of the other rotor. The heated cooling fluid is conveyed in the lubrication circuit to the heat exchanger.In the heat exchanger, the cooling fluid is cooled and the supply air is heated.

[0007] The advantage of the power plant according to the invention is that it produces lower noise emissions and also requires less installation and maintenance. No separate cooling circuit or fans are required, thus reducing energy consumption.

[0008] An incineration plant is understood, in particular, to be a device for generating thermal energy by burning a fuel. The fuel used is, in particular, fuel gas, oil, biomass, and / or a solid fuel, especially wood or pellets. The biomass can be solid, liquid, or gaseous.

[0009] A combustion chamber is the space in which the fuel is burned.

[0010] A turbine is a device for converting thermal energy into mechanical work, particularly a steam turbine. A rotor is a shaft, particularly a turbine shaft. Mechanical work is performed by moving the rotor.

[0011] A heat exchanger is understood in particular to be a device that transfers thermal energy from one material stream to another.

[0012] A lubricating oil is used as the cooling fluid.

[0013] The power plant preferably has a condenser for condensing the steam after it exits the turbine. This makes it possible to close a liquid circuit, in which the liquid is preferably passed sequentially through the combustion system, the turbine, and the condenser. A liquid pump is preferably arranged on the liquid circuit to convey the liquid in the liquid circuit.

[0014] The turbo set preferably has a single-shaft arrangement. In a single-shaft arrangement, the turbine rotor and the generator rotor are formed integrally. Alternatively, the turbo set has a multi-shaft arrangement. In this case, the turbo set preferably has a gearbox. This gearbox is advantageously arranged between the turbine and the generator.

[0015] Preferably, the lubrication circuit is designed to lubricate and cool the bearings of the turbine, generator, and / or gearbox. This way, the heat generated in the turbo set is directly dissipated from the moving components, simultaneously lubricating them.

[0016] The heat exchanger is preferably arranged on or at least partially, but preferably entirely, within the supply air duct. This enables efficient heating of the supply air.

[0017] The power plant is preferably designed to additionally heat the supply air downstream of the heat exchanger in the direction of flow. This has the advantage that the efficiency of the combustion plant is further increased and any fluctuations in the temperature of the supply air can be compensated for. For this purpose, a heating device is preferably arranged downstream of the heat exchanger on or in the supply air line. For example, a further heat exchanger, in particular a finned tube heater, is arranged on or in the supply air line. A heating fluid preferably flows through the heating device, which heats the heating device. Water and / or heat transfer oil are used in particular as the heating fluid. The heating fluid is heated in particular by the waste heat from the combustion plant and / or other waste heat from the power plant.

[0018] Preferably, at least one temperature sensor is arranged on or in the supply air duct, which is configured to detect an actual supply air temperature and send a signal to a control unit. The control unit is preferably configured to control the heating device depending on the signal from the at least one temperature sensor in order to heat the supply air to a predeterminable target supply air temperature. This has the advantage that, even if the supply air is heated fluctuatingly by the heat exchanger, a constant supply air temperature is ensured by the heating device.

[0019] A further development of the invention is characterized in that the supply air line is a secondary air supply line for supplying secondary air into the combustion chamber. In this variant, the supply air is divided at least into primary air and secondary air. In principle, it is possible to further divide the supply air, in particular into tertiary air.

[0020] Primary air is the air that is fed into the combustion chamber under a grate. Secondary air is the air that is fed into the combustion chamber above the grate. In particular, secondary air is fresh air taken from the environment surrounding the combustion plant. A grate is understood to be an element in the combustion chamber on or in which the fuel is located.

[0021] The power plant either has at least two air supply lines or the air supply line is at least split into two. The primary air is fed into the combustion chamber via a primary air supply line. The secondary air is fed into the combustion chamber via a secondary air supply line.

[0022] Heating the secondary air has the advantage of increasing the efficiency of the combustion system. In particular, preheated secondary air saves fuel. At the same time, the secondary air flow is a predominantly continuous air flow, thus achieving continuous cooling of the cooling fluid. Furthermore, the secondary air flow—as provided in a preferred embodiment—is larger than the primary air flow, thus achieving high cooling capacity.

[0023] A further advantage of heating the secondary air is that more secondary air is usually supplied to the combustion chamber than primary air and thus a greater heat transfer can usually be achieved at the secondary air supply line.

[0024] Preferably, the heat exchanger is located on a secondary air supply line, and another heat exchanger is located on the primary air supply line. This allows for greater cooling performance of the cooling fluid in the lubrication circuit and simultaneously increases the efficiency of the power plant.

[0025] Preferably, the power plant has a control unit configured to adjust a predeterminable primary air flow and / or a predeterminable secondary air flow. For example, a controllable valve, controlled by the control unit, is arranged on the corresponding supply air line, or a controllable fan, controlled by a control unit, is arranged in the corresponding supply air line. The combustion quality of the fuel can be controlled by changing the primary air flow and / or the secondary air flow.

[0026] Preferably, the secondary air supply line is divided downstream of the heat exchanger into several secondary air supply sections connected in parallel in terms of flow. The secondary air supply sections preferably open into the combustion chamber via secondary air inlets at various locations, in particular at different heights. Advantageously, two or more secondary air inlets are arranged diametrically opposite one another and / or equally spaced from one another in the circumferential direction at at least one height on the combustion chamber. Preferably, secondary air inlets are arranged on the combustion chamber at at least two, preferably at at least three, in particular at at least four different heights.

[0027] Preferably, the combustion plant is a biomass combustion boiler and / or a solid fuel combustion boiler, in particular a wood combustion boiler or a pellet combustion boiler. In particular, the power plant preferably has a biomass feeder arranged to feed biomass into the combustion chamber.

[0028] The preferred heat exchanger is a finned-tube heat exchanger. The advantage of using finned-tube heat exchangers is that they are relatively inexpensive to purchase, robust, adaptable, and require relatively little space.

[0029] The heat exchanger is preferably designed as an oil / air heat exchanger. In particular, the heat exchanger is configured to transfer thermal energy from the cooling fluid flow of the lubrication circuit to the air flow in the supply air line. Preferably, the cooling fluid flow in the heat exchanger is directed counter to the air flow in the supply air line. This achieves efficient heat transfer. In particular, no intermediate medium is required, which would increase the efficiency and the effort required to operate and maintain the system.

[0030] A further development of the invention is characterized in that the rotor is arranged in the turbine via at least one bearing, and the at least one bearing is fluidly connected to the lubrication circuit. Preferably, the lubrication circuit is arranged for lubricating and cooling the at least one bearing.

[0031] The power plant preferably has an emergency cooling device for cooling the cooling fluid. The emergency cooling device can preferably be switched on and off. If the temperature of the cooling fluid exceeds a predetermined maximum temperature, the emergency cooling device is automatically activated. The maximum temperature is selected in particular such that, if exceeded, sufficient cooling of the cooled and lubricated components of the turbocharger set, in particular the turbine rotor, is not ensured.

[0032] For this purpose, at least one temperature sensor for detecting an actual cooling fluid temperature is preferably arranged on the lubrication circuit, which temperature sensor sends a signal to a control unit. The emergency cooling device preferably has the at least one temperature sensor and / or the control unit. The control unit is preferably configured to activate the emergency cooling device as soon as the actual cooling fluid temperature meets a predeterminable criterion, in particular is above a predeterminable limit value. The control unit is preferably configured to deactivate the emergency cooling device as soon as the actual cooling fluid temperature is within a predeterminable target range and / or below a further predeterminable limit value. The emergency cooling device particularly has an emergency cooling heat exchanger for cooling the cooling fluid, through which cooling water flows, for example.The control unit is preferably configured to activate a cooling water pump for pumping cooling water into the emergency cooling heat exchanger when the actual cooling fluid temperature is above a predeterminable limit value.

[0033] The heat exchanger is preferably located at a distance of no more than 50 m, preferably no more than 20 m, and particularly preferably no more than 10 m from the turbine generator and / or the combustion plant. This reduces the heat losses of the cooling fluid on the way from the turbine generator to the heat exchanger and / or the heat losses of the supply air on the way from the heat exchanger to the combustion plant.

[0034] According to a second aspect, the invention relates to a method for operating a power plant with a combustion plant having a combustion chamber and an air supply line for supplying supply air, with a turbo set having a generator and a turbine with a rotor, with a lubrication circuit and with a heat exchanger, comprising the steps of: (a) lubricating and cooling the turbo set with a cooling fluid circulating in the lubrication circuit, (b) supplying the cooling fluid to the heat exchanger and (c) heating the supply air by the heat exchanger.

[0035] Preferably, a filter for filtering the cooling fluid is arranged on the lubrication circuit.

[0036] The invention is explained in more detail below with reference to the accompanying drawings. Figure 1 shows a schematic representation of a power plant according to the invention in a first variant, Figure 2 shows a schematic representation of a power plant according to the invention in a second variant and Figure 3 shows a schematic representation of a liquid circuit in a power plant according to the invention.

[0037] Figure 1 shows a schematic representation of a power plant according to the invention with a combustion plant 10 and a turbogenerator 20. The combustion plant 10 has a boiler 11 with a combustion chamber (not shown). A liquid line (not shown) runs through the combustion chamber, conveying a liquid. The liquid in the liquid line evaporates to steam as it passes through the combustion chamber.

[0038] The combustion plant has two supply air lines 14, one supply air line 14 being a primary air supply line 16 through which primary air is fed from below into the combustion chamber, and the other supply air line 14 being a secondary air supply line 18 through which secondary air is fed laterally into the combustion chamber.

[0039] A fan 50 is arranged on each of the primary air supply line 16 and the secondary air supply line 18. In principle, it is also possible to provide a single supply air line instead of two separate supply air lines 14, which may be split into a primary air supply line 16 and a secondary air supply line 18. In this case, it is sufficient to arrange one fan 50 on the supply air line 14.

[0040] A heat exchanger 40 for heating the secondary air is arranged in or on the secondary air supply line 18. For example, the heat exchanger is a finned-tube radiator through which the cooling fluid flows and around which the supply air, in particular the secondary supply air, flows.

[0041] In the illustrated embodiment, the secondary air supply line is divided into several secondary air supply line sections 19 in the direction of flow of the secondary air downstream of the heat exchanger 40, which at their ends discharge into the combustion chamber via secondary air inlets. The secondary air inlets are arranged at different heights, with two secondary air inlets each arranged at the same height and diametrically opposite each other. It is also possible to arrange more than two secondary air inlets at the same height, which are preferably equally spaced from each other in the circumferential direction.

[0042] The turbo set 20 has a turbine 22, a gearbox 23, a generator 26, and several bearings 28. The turbine 22 has a rotor 24. The generator 26 has another rotor 27. The rotor 24 is the drive shaft of the gearbox 23, while the other rotor 27 is the drive shaft of the gearbox 23. The gearbox serves to convert and transmit a torque of the rotor 24 into a torque of the other rotor 27. The rotor 24 and the other rotor 27 are each mounted on two bearings 28.

[0043] The bearings 28 and the gearbox 23 are fluidically connected to a lubrication circuit 30. The cooling fluid line sections where the bearings 28 are arranged are fluidically connected in parallel. A cooling fluid circulates in the lubrication circuit 30 to lubricate and cool the turbo set.

[0044] A tank 34 for the cooling fluid is arranged on the lubrication circuit 30. From the tank 34, the cooling fluid is moved within the lubrication circuit 30 by means of cooling fluid pumps 32. In the variant shown, the three cooling fluid pumps 32 are arranged on two parallel cooling fluid line sections, with two cooling fluid pumps arranged in parallel on one of these cooling fluid line sections. A filter 38 for filtering the cooling fluid is arranged on one cooling fluid line section. It is also possible to use only one cooling fluid pump to pump the cooling fluid. Furthermore, it is possible to arrange an additional emergency cooling fluid pump in the lubrication circuit 30, which is activated only in the event of a power failure to the power plant.

[0045] The lubrication circuit 30 has a cooling section 36 and a lubrication section 35. The cooling section 36 and the lubrication section 35 are two sub-circuits connected to each other via the tank 34. The heat exchanger 40 is arranged in the cooling section 36. In the cooling section 36, the cooling fluid is cooled as it passes through the heat exchanger 40. The turbo set 20 is arranged in the lubrication section 35. In the lubrication section 35, the cooling fluid is heated as it passes through the turbo set 20. The cooling fluid in the lubrication section 35 simultaneously lubricates and cools the turbo set 20.

[0046] A cooling fluid pump 32 is arranged at the cooling section 36, via which the cooling fluid is pumped from the tank 34 into the heat exchanger 40 and from the heat exchanger 40 back into the tank 34. The heat exchanger 40 is arranged on or in the secondary air supply line 18. The cooling fluid of the lubrication circuit 30 is cooled as it passes through the heat exchanger 40. At the same time, the secondary air in the secondary air supply line 18 is heated as it passes through the heat exchanger 40.

[0047] Figure 2 shows a schematic representation of a second variant of a power plant according to the invention. The power plant has an incinerator 10 and a turbine generator 20. The incinerator 10 has a boiler 11 with a combustion chamber 12. A grate 13 is arranged in the combustion chamber 12, on which a fuel 70 is arranged.

[0048] Supply air is fed into the combustion chamber 12 via an air supply line 14. A fan 50 for conveying the supply air is arranged on the air supply line 14. Downstream of the fan 50 in the direction of flow, the air supply line 14 is divided into a primary air supply line 16 and a secondary air supply line 18. Primary air is fed below the grate 13 into the combustion chamber 12 via the primary air supply line 16. Secondary air is fed above the grate 13 into the combustion chamber via the secondary air supply line 18. In principle, it is also possible to feed the supply air into the combustion chamber via a single line. An exhaust gas nozzle 15 for discharging the exhaust gases is arranged on the top of the boiler 11.

[0049] The turbo set 20 has a turbine 22 with a rotor 24, a generator 26, and several bearings 28. The bearings 28 are arranged outside the turbine 22 and the generator 26. In principle, it is possible to arrange bearings 28, in particular all bearings 28, in the turbine and / or in the generator 26. The rotor 24 of the turbine 22 is also the rotor of the generator 26. The bearings 28 serve to support the rotor 24. This arrangement is referred to as a single-shaft arrangement. It is also possible to arrange a gearbox between the turbine 22 and the generator 26 in a multi-shaft arrangement.

[0050] The bearings 28 are fluidly connected to a lubrication circuit 30. A cooling fluid circulates in the lubrication circuit 30 to lubricate and cool the turbo set 20. A tank 34 is arranged on the lubrication circuit 30. A cooling fluid pump 32 pumps the cooling fluid into the lubrication circuit 30. The cooling fluid line sections on which the bearings 28 are arranged are fluidly connected in parallel.

[0051] After passing through the turbo set 20, the cooling fluid is fed into the heat exchanger 40 by means of another cooling fluid pump 33. The other cooling fluid pump 33 is arranged downstream of the turbo set 20 and upstream of the heat exchanger 40. The heat exchanger 40 is arranged in or on the supply air line 14. The cooling fluid is cooled as it flows through the heat exchanger 40, while the supply air in the supply air line 14 is heated as it passes through the heat exchanger 40.

[0052] In the embodiment shown, an emergency cooling device 80 is arranged on the lubrication circuit 30 downstream of the heat exchanger 40. Alternatively, the emergency cooling device 80 can also be arranged upstream of the heat exchanger 40. The emergency cooling device 80 is activated when the actual cooling fluid temperature of the cooling fluid in the lubrication circuit 30 exceeds a predeterminable maximum temperature. This ensures that the turbo set 20 is sufficiently cooled by the cooling fluid and that no components are damaged.

[0053] To detect the actual cooling fluid temperature, the emergency cooling device 80 has a temperature sensor (not shown) arranged on the lubrication circuit 30. The temperature sensor sends a signal to a control unit (not shown), which is configured to activate the emergency cooling device 80 when the actual cooling fluid temperature meets a predeterminable criterion, in particular is above the predeterminable maximum temperature. In particular, the control unit is configured to deactivate the emergency cooling device 80 when the actual cooling fluid temperature is within a predeterminable target range and / or below a further predeterminable limit value. The emergency cooling device 80 has, for example, an emergency cooling heat exchanger through which cooling water flows and around which the cooling fluid flows. To activate and deactivate the emergency cooling device 80, the control unit then controls, for example, a cooling water pump to pump cooling water into the emergency cooling heat exchanger.

[0054] Figure 3 shows a schematic liquid circuit 60 in a power plant according to the invention. The liquid, in particular water, is set in motion by means of a liquid pump 62. First, the liquid passes through the combustion chamber 12, where it evaporates into steam due to heating. The steam is passed from the combustion chamber 12 into the turbine 22, where the steam is used to drive the rotor of the turbine 22. From the turbine 22, the steam is passed on to the condenser 64. The steam condenses in the condenser 64. From the condenser 64, the liquid is pumped to the liquid pump 62, and the cycle begins again. A liquid tank can be arranged on the liquid circuit 60. List of reference symbols 10 incineration plant 27 additional rotor 11 boiler 28 warehouse 12 combustion chamber 30 Lubrication circuit 13 rust 32 Cooling fluid pump 14 Supply air duct 33 additional cooling fluid pump 15 exhaust nozzle 34 tank 16 Primary air supply 36 Cooling section 18 Secondary air supply line 38 filter 19 Secondary air supply sections 40 heat exchanger 20 Turbo set 50 fan 22 turbine 60 Fluid circulation 23 Gearbox 62 liquid pump 24 rotor 64 capacitor 26 generator 70 fuel 80 Emergency cooling device

Claims

1. A power station with (a) an furnace (10) with (i) a combustion chamber (12) for generating steam and (ii) an air supply line (14) for feeding supply air into the combustion chamber (12), (b) a turboset (20) with (i) a turbine (22) with a rotor (24) and (ii) a generator (26), (c) a lubricant circuit (30) for lubricating and cooling the turboset (20), wherein a coolant circulates in the lubricant circuit (30), and (d) a heat exchanger (40) for cooling the coolant, wherein (e) the heat exchanger (40) is arranged to heat the supply air.

2. The power station according to claim 1, characterized in that the lubricant circuit (30) is arranged to lubricate and cool the bearings (28) of the turbine (22), the generator (26) and / or a transmission (23).

3. The power station according to claim 1 or 2, characterized in that the heat exchanger (40) is arranged on or at least partially, but preferably fully, in the air supply line (14).

4. The power station according to one of the preceding claims, characterized in that the power station is configured to additionally heat the supply air downstream of the heat exchanger (40) in the direction of flow.

5. The power station according to one of the preceding claims, characterized in that the air supply line (14) is a secondary air supply line (18) for feeding secondary air into the combustion chamber (12).

6. The power station according to claim 5, characterized in that the secondary air supply line (18) is divided into several secondary air supply line sections (19) fluidically connected in parallel in the direction of flow downstream of the heat exchanger (40).

7. The power station according to one of the preceding claims, characterized in that the furnace (10) is a biomass combustion furnace and / or a solid fuel combustion furnace, particularly a wood combustion furnace or a pellet combustion furnace.

8. The power station according to one of the preceding claims, characterized in that the heat exchanger (40) is a finned tube heat exchanger.

9. The power station according to one of the preceding claims, characterized in that the rotor (24) is arranged in the turbine (22) via at least one bearing (28) and the at least one bearing (28) is fluidically connected to the lubricant circuit (30).

10. The power station according to one of the preceding claims, comprising an emergency cooling device (80) for cooling the coolant by means of cooling water.

11. The power station according to one of the preceding claims, characterized in that the heat exchanger (40) is arranged at most 50m, preferably at most 20m, especially preferably at most 10m, away from the turboset (20) and / or the furnace (10).

12. A method for operating a power station with an furnace (10) comprising a combustion chamber (12) and an air supply line (14) for feeding supply air; a turboset (20) comprising a generator (26) and a turbine (22) with a rotor (24); a lubricant circuit (30) and a heat exchanger (40), comprising the steps: (a) lubricating and cooling the turboset (20) with a coolant that circulates in the lubricant circuit (30), (b) feeding the coolant into the heat exchanger (40), (c) heating the supply air through the heat exchanger (40).

13. The method according to claim 12, further comprising the step (a) recording a temperature of the coolant and (b) cooling the coolant by means of an emergency cooling device (80) if the temperature exceeds a maximum temperature.