Device for generating a gaseous fluid in the form of steam and device for generating electrical energy, as well as method for generating a gaseous fluid in the form of steam and method for generating electrical energy

Abstract

Device (1) for generating a gaseous fluid (41) in the form of steam by converting thermal energy, comprising a combustion system (20) for releasing thermal energy and a heat transfer device (30) for at least partially converting a liquid fluid (40) into a gaseous fluid (41) by transferring released energy to the liquid fluid (40), wherein the device for generating a gaseous fluid comprises a thermally insulated space (10) and the heat transfer device (30) is arranged at least partially within the thermally insulated space (10), characterized in that the device further comprises a condensation device (53) for at least partially condensing the gaseous fluid (41) into a liquid fluid (40), which is arranged at least partially within the thermally insulated space (10).wherein the heat released during condensation can be supplied to the heat-insulated space (10) and thus can be used for converting the liquid fluid (40) into a gaseous fluid (41) in the heat transfer device (30).

Description

[0001] The invention relates to a device for generating a gaseous fluid in the form of steam and to a device for generating electrical energy. Furthermore, the invention relates to a method for generating a gaseous fluid in the form of steam and to a method for generating electrical energy.

[0002] Steam, especially water vapor, is typically generated in steam boilers. Steam boilers transfer thermal energy generated by the combustion of fossil fuels such as oil, coal, or gas to a liquid medium and evaporate it. The medium to be evaporated is heated to or above its boiling point.

[0003] A common design for steam boilers is the shell boiler. Shell boilers contain a firing system or combustion chamber within the water-filled boiler chamber. The combustion chamber, where combustion takes place, is completely enclosed by the water to be evaporated. To more efficiently utilize the heat generated during combustion, it is common practice for the flue gases produced during combustion to be directed through the volume of water to be evaporated in flue gas ducts.

[0004] Another common design for steam generation is the so-called water-tube boiler. In this design, the water to be evaporated is conveyed through tubes through a chamber filled with the hot flue gas from combustion, or through the combustion chamber itself.

[0005] The steam generated by steam boilers can be used to generate electrical energy. To do this, the steam's energy is typically converted into electrical energy using a turbine and a generator connected to the turbine. The turbine is usually followed by a condenser, in which the now-expanded steam is converted back into a liquid, releasing the heat still present in the steam. This liquid is then returned to the steam boiler.

[0006] The energy efficiency of the overall process is negatively impacted primarily by heat losses. The lower the efficiency, the more raw material must be used to generate the desired amount of energy. In addition to the resulting increased costs for the raw material to be burned, this also results in increased emissions of combustion residues and combustion gases into the environment.

[0007] DE 102011121471 A1 discloses a heat accumulator for storing waste heat for a vehicle. The heat accumulator is filled with a fluid and a circuit of elements containing a phase-change material. Furthermore, a method and a system for generating mechanical or thermal energy from waste heat of a vehicle are disclosed. The waste heat contained in the vehicle's exhaust gas is stored in a heat accumulator. The heat accumulator is filled with a fluid and a phase-change material. The mechanical or thermal energy is generated using a gas portion of the fluid provided by the heat accumulator.

[0008] DE 102010038314 A1 proposes a drive system for a vehicle, comprising an internal combustion engine releasing mechanical and thermal energy and a device for converting the thermal energy, wherein the device is designed for directly converting the thermal energy into electrical energy and for transferring thermal energy to a working medium provided for acting on an expansion device.

[0009] WO 2014 / 089716 A2 teaches a device for generating electrical energy from thermal energy, comprising a thermally insulated heat storage unit with a storage medium, a heat engine with a working medium and a generator for generating electrical energy from mechanical energy, wherein energy stored in the heat storage unit can be converted by the heat engine into mechanical energy and this can be converted into electrical energy via the generator.

[0010] The object to be achieved by the invention is to provide a device and a method for generating a gaseous fluid in the form of steam as well as a device and a method for generating electrical energy, which increase the efficiency in the generation of steam and electrical energy and are thus cost-saving and environmentally friendly.

[0011] The object is achieved according to the invention by a device for generating a gaseous fluid in the form of steam according to claim 1, a device for generating electrical energy according to claim 6 and a method for generating a gaseous fluid in the form of steam according to claim 9 and a method for generating electrical energy according to claim 10. Advantageous embodiments of the device according to the invention for generating a gaseous fluid in the form of steam are specified in subclaims 2 to 5. Advantageous embodiments of the device for generating electrical energy are specified in subclaims 7 to 8.

[0012] A first aspect of the invention is a device for generating a gaseous fluid in the form of steam by converting thermal energy, which device comprises a combustion system for releasing thermal energy and a heat transfer device for at least partially converting a liquid fluid into a gaseous fluid by transferring released energy to the liquid fluid, wherein the device for generating a gaseous fluid comprises a thermally insulated space and the heat transfer device is arranged at least partially within the thermally insulated space.

[0013] It is provided that the device for generating a gaseous fluid in the form of vapor further comprises a condensation device for at least partially condensing the gaseous fluid into a liquid fluid, which is arranged at least partially within the thermally insulated space, wherein the heat released during the condensation can be supplied to the thermally insulated space and can thus be used for converting the liquid fluid into a gaseous fluid in the heat transfer device.

[0014] The gaseous fluid can also be referred to as a vaporous fluid or steam. Therefore, the device for generating a gaseous fluid can also be referred to as a steam generation device or an evaporator system. The aforementioned steam generation device is, in particular, a micro-evaporator system with a power output of up to 10 kW.

[0015] The evaporator system comprises a combustion system. A fuel is fed to the combustion system, which is thermally converted within the combustion system, whereby the chemical energy of the fuel is released in the form of thermal energy. The thermal energy is used in the heat transfer device to at least partially convert a liquid fluid, preferably water, into a gaseous fluid. Preferably, the liquid fluid is completely converted into a gaseous fluid. Particularly preferably, the liquid fluid is converted into superheated steam. Superheated steam is characterized by having a higher temperature than the boiling point of the respective fluid. Superheated steam is generally dry, meaning that it does not contain any liquid droplets.

[0016] A heat transfer device is a technical unit that enables heat transfer between at least two media, a first of which has a higher temperature than a second, without these media coming into material contact with one another. According to the invention, the first of the media mentioned is the flue gas produced during combustion, and the second medium is the liquid fluid to be evaporated. The media are separated from one another within the heat transfer device by a generally solid partition wall that has the highest possible thermal conductivity. For example, pipes can be used, with one of the media flowing inside the pipe and the other medium flowing outside. The heat is transferred from one medium to the other via the pipe wall.Other designs in which, for example, the two media are separated from each other by partition walls or panels with flat or structural elements are also possible.

[0017] In one embodiment, the two media between which heat transfer takes place flow in the same direction through the heat transfer device along the dividing wall, namely according to the cocurrent principle. In another embodiment, the two media flow in opposite directions, namely according to the countercurrent principle. It is also possible for the flows of the two media to intersect, namely according to the crosscurrent principle.

[0018] The heat transfer device can be designed as a water-tube boiler or a smoke-tube boiler. In the water-tube boiler embodiment, the at least partially liquid fluid is guided in preferably several tubes within a chamber filled with the flue gas produced by combustion. In the smoke-tube boiler embodiment, however, the flue gas is guided in preferably several tubes through a chamber filled with an at least partially liquid fluid.

[0019] The device for generating a gaseous fluid in the form of steam also includes a thermally insulated space.

[0020] The heat transfer device is arranged at least partially, but preferably completely, within the thermally insulated space. The thermally insulated space comprises a boundary to its surroundings, which is designed in such a way that heat flow through the boundary is at least partially prevented. The function of the thermally insulated space is to partially, preferably completely, prevent heat loss. The heat loss is the heat flow that is released to the external environment of the thermally insulated space and whose energy cannot therefore be used to convert the liquid fluid into a gaseous fluid. The heat loss can also be referred to as transmission heat loss.The advantage of the device according to the invention for generating a gaseous fluid in the form of steam lies in a more efficient use of the energy released during the combustion of the fuel, which results not only in cost savings for the fuel but also in a more environmentally friendly production of gaseous fluid or steam.

[0021] In a further embodiment, the heat transfer device comprises an evaporator for converting the at least partially liquid fluid into a gaseous fluid and / or a superheater for converting the at least partially gaseous or vaporous fluid into a superheated gaseous or vaporous fluid and / or an economizer for preheating the at least partially liquid fluid, wherein the evaporator, superheater and economizer each transfer the thermal energy released by the combustion plant to the at least partially liquid or gaseous fluid.

[0022] Viewed in the direction of fluid flow, the liquid fluid first flows through the economizer, where it is preheated by the residual heat of the flue gas, which flows through the economizer after the evaporator and superheater. From here, the preheated fluid flows into the evaporator. Here, the fluid is vaporized using the heat of the flue gas, which reaches its maximum temperature in this stage. In the final stage, the superheater, further thermal energy from the flue gas is transferred to the gaseous fluid, causing it to be superheated.

[0023] Preferably, the gaseous fluid is completely condensed in the condensation device. Furthermore, the condensation device is preferably arranged entirely within the thermally insulated space.

[0024] One embodiment of the device for generating a gaseous fluid in the form of steam consists in that the combustion plant for converting the chemical energy of a supplied fuel into thermal energy comprises at least one burner and at least one combustion chamber, wherein the combustion plant, at least partially, but at least the combustion chamber, is arranged within the thermally insulated space.

[0025] A burner is a technical device in which fuel and an oxidizing agent, preferably air, are mixed and ignited. The combustion chamber is the part of the combustion system where combustion takes place with an open flame. The combustion chamber can also be referred to as the combustion chamber.

[0026] Basically, three designs are possible regarding the arrangement of the incineration plant.

[0027] In the first case, both the burner and the combustion chamber are located within the thermally insulated space of the steam generation device. In the second case, the burner is located outside the boundaries of the thermally insulated space, and the combustion chamber is located partially or, preferably, entirely within the thermally insulated space. The advantage of these two arrangements is that the flame—in other words, the site of conversion of chemical fuel energy into thermal energy—is located within the thermally insulated space, minimizing energy losses during the combustion process itself. However, in a third case, it is also possible to locate the combustion device entirely outside the thermally insulated space and to feed the flue gas to the heat transfer device via a flue gas line.

[0028] The incineration plant can be designed for solid, liquid or gaseous fuels.

[0029] A further embodiment of the device for generating a gaseous fluid in the form of vapor consists in that the thermally insulated space is insulated from the immediate spatial environment in such a way that the heat loss is less than 5% relative to the heat output of the device for generating a gaseous fluid in the form of vapor. Particularly preferably, the heat loss is less than 2%.

[0030] Thermal output is the portion of the power that can be used as heat during the conversion of chemical energy into thermal energy. Thermal output corresponds to the combustion heat input minus losses due to incomplete combustion, residual heat in the flue gas, and heat losses from the combustion plant. The combustion heat output is the heat content of a fuel, relative to its lower calorific value, that can be supplied to a combustion plant per unit of time during continuous operation.

[0031] The heat loss is the heat loss that is released beyond the boundaries of the thermally insulated space, also related to continuous operation.

[0032] A further embodiment of the device for generating a gaseous fluid in the form of steam provides that the device is designed to carry out natural circulation processes, forced circulation processes or forced once-through processes, wherein the device in the embodiment for carrying out the forced circulation process or the forced once-through process additionally comprises at least one pump for conveying the liquid fluid.

[0033] In the device for generating a gaseous fluid in the form of steam, the fluid is circulated. The fluid leaves the heat transfer device in gaseous form, condenses, and flows back into the heat transfer device in a substantially liquid state. When water is used as the fluid, this cycle is called a water-steam cycle. The cycle is at least partially, preferably completely, closed. This means that no fluid is lost during the fluid's circulation, thus the water mass within the cycle remains constant.

[0034] The natural circulation process is characterized by the fact that the circulation is achieved through the density difference between the liquid fluid and the gaseous fluid without active conveying.

[0035] In forced circulation and forced once-through processes, active conveyance of the liquid fluid into the heat transfer device is required to achieve the circulation. To achieve this, at least one pump is preferably arranged between the condensation device and the heat transfer device, which conveys the liquid fluid toward the heat transfer device.

[0036] In a further embodiment, the device for generating a gaseous fluid in the form of steam further comprises a bypass which enables the at least partially gaseous or vaporous fluid generated by the heat transfer device to be at least partially returned to the heat transfer device, bypassing a system for utilizing the steam connected to the device for generating steam, such as a power generation device. In particular, at the start of operation of the device for generating a gaseous fluid in the form of steam, the return of the fluid via the bypass serves to quickly increase the necessary operating temperature of the circulating fluid and thus to achieve the required operating conditions for the device for generating steam in a shorter time.

[0037] A further aspect of the invention is a device for generating electrical energy, which comprises a device for generating a gaseous fluid in the form of steam and a power generation device for converting the kinetic energy of the steam and / or the internal energy of the steam into electrical energy, wherein the power generation device is fluidly coupled to the device for generating a gaseous fluid in the form of steam in such a way that the gaseous fluid can be supplied to the power generation device.

[0038] In a further embodiment, the power generation device comprises at least one turbine for converting the energy of the steam into mechanical work and at least one generator for converting the mechanical work into electrical energy.

[0039] To implement the forced-flow or forced-circulation process, the pump is preferably powered by the electrical energy generated or provided by the power generation device. Alternatively, the pump is powered from the utility grid.

[0040] In a further embodiment, the device for generating electrical energy comprises a control device that is connected to the power generation device and the steam generation device. It fulfills the function of regulating the control variables of the combustion process, in particular the mass flows of fuel and oxidant, depending on the current power values of the generator of the power generation device.

[0041] In a further embodiment, the device for generating electrical energy further comprises an equalizing vessel for compensating pressure and / or volume fluctuations within flow-through components of the device for generating electrical energy.

[0042] The compensation vessel is preferably arranged in the flow direction of the liquid fluid between the condensation device and the device for generating steam.

[0043] The individual devices, which together form the electrical energy generation system, are connected to each other via a piping system. Within this overall system, the fluid flows in liquid and gaseous or vaporous states, preferably in a closed circuit. The function of the expansion tank is to compensate for pressure and volume fluctuations within this overall system and to ensure that all components carrying the fluid are filled at all times to the level required for proper operation. One advantage of this design is the compact structural design of the overall system.

[0044] According to the invention, a method for generating a gaseous fluid in the form of steam by converting thermal energy is further provided, in which a device according to the invention for generating a gaseous fluid in the form of steam is provided and steam is generated with this device.

[0045] Furthermore, a method for generating electrical energy is provided, in which a device according to the invention for generating electrical energy is provided and by means of this device the kinetic energy of the gaseous fluid and / or the internal energy of the gaseous fluid is converted into electrical energy.

[0046] The invention is explained below with reference to the embodiments shown in the accompanying drawings.

[0047] It shows Fig. 1: a schematic representation of an embodiment of the device for generating electrical energy including a device for generating a gaseous fluid in the form of steam as a process flow diagram and Fig. 2: a schematic representation of an embodiment of the device for generating a gaseous fluid in the form of steam as a process flow diagram.

[0048] Fig. Figure 1 shows a device for generating electrical energy 2 in the form of a process flow diagram. It can be seen that a fluid is circulated through the device as a liquid fluid 40 or a gaseous fluid 41. The flow direction is indicated by arrows.

[0049] The device comprises a device 1 for generating a gaseous fluid 41 in the form of steam. A fuel is supplied to a combustion system 20 via a fuel supply 21. The combustion system 20 comprises a burner and a combustion chamber (in Fig. 1 not shown). The flue gas produced during combustion is passed - in the illustration from left to right - through a heat transfer device 30. The heat transfer device 30 is located entirely in a thermally insulated space 10. By arranging the heat transfer device 30 in the thermally insulated space 10, heat output losses are reduced and the efficiency of the heat transfer process is increased. In the illustration, a liquid fluid 40 enters the heat transfer device from above and leaves the heat transfer device 30 downwards as a gaseous fluid 41. The gaseous fluid 41 is passed on to a turbine 51, which is part of a power generation device 50. The turbine 51 is connected to a generator 52. In the turbine 51, the gaseous fluid 41 is expanded.The energy of the gaseous fluid 41 is converted into mechanical work in the turbine 51, which in turn is converted into electrical energy by the generator 52. The generator is connected via a control device 55 to the fuel supply 21 and thus to the device 1 for generating a gaseous fluid 41 in the form of steam.

[0050] The gaseous fluid 41 is guided from the turbine 51 to the condensation device 53, where it condenses. The condensation device 53 is arranged entirely within the thermally insulated space 10. This arrangement of the condensation device 53 serves to utilize the condensation heat for converting a liquid fluid 40 into a gaseous fluid 41 in the heat transfer device 30. The fluid leaves the condensation device 53 as liquid fluid 40, then flows through a pump 60, which serves to convey the liquid fluid 40, and is then returned to the device for generating steam 1. The pump 60 is connected to the power generation device 50 so that it can be fed by it. An equalizing tank 54 is connected to the connection between the pump 60 and the device 1 for generating a gaseous fluid 41.

[0051] In the middle part of the process flow diagram, a bypass 34 is shown, with which the gaseous fluid 41 can be returned to the heat transfer device 30, bypassing the power generation device 50, the condenser 53, the pump 60 and the compensation vessel 54.

[0052] Fig.Figure 2 shows a specific embodiment of the device 1 for generating a gaseous fluid 41 in the form of steam. It shows the combustion system 20 and the heat transfer device 30, which is arranged within the thermally insulated space 10. The heat transfer device 30 comprises an evaporator 31, a superheater 32 and an economizer 33. The liquid fluid 40 flows, in the illustration coming from above, first through the economizer 33, then the evaporator 31 and finally the superheater 32 and leaves the device 1 to generate a gaseous fluid 41 in the form of steam as a gaseous fluid 41. The flue gas produced in the combustion system 22 flows from left to right first through the evaporator 31, then the superheater 32 and finally the economizer 33. The multi-stage design of the heat transfer device 30 serves to more efficiently use the heat of combustion or the thermal energy of the flue gas. List of reference symbols 1 Device for generating a gaseous fluid in the form of steam 2 Facility for generating electrical energy 10 thermally insulated rooms 20 incineration plant 21 Fuel supply 30 Heat transfer device 31 evaporators 32 superheaters 33 Economizer 34 Bypass 40 Fluid gaseous 41 Fluid liquid 50 power generation facility 51 turbines 52 Generator 53 Condensation device 54 Expansion tank 55 Control device 60 pump

Claims

[1] Device (1) for generating a gaseous fluid (41) in the form of steam by converting thermal energy, comprehensive an incineration plant (20) for releasing thermal energy and a heat transfer device (30) for at least partially converting a liquid fluid (40) into a gaseous fluid (41) by transferring released energy to the liquid fluid (40), wherein the device for generating a gaseous fluid comprises a thermally insulated space (10) and the heat transfer device (30) is arranged at least partially within the thermally insulated space (10), characterized by , that the device further comprises a condensation device (53) for at least partially condensing the gaseous fluid (41) into a liquid fluid (40), which is arranged at least partially within the thermally insulated space (10), wherein the heat released during the condensation can be supplied to the thermally insulated space (10) and can thus be used for converting the liquid fluid (40) into a gaseous fluid (41) in the heat transfer device (30). [2] Device (1) for generating a gaseous fluid (41) according to claim 1, characterized by that the combustion plant (20) for converting the chemical energy of a supplied fuel into thermal energy comprises at least one burner and at least one combustion chamber, wherein the combustion plant (20) is arranged at least partially, but at least the combustion chamber, within the thermally insulated space (10). [3] Device (1) for generating a gaseous fluid (41) according to at least one of the preceding claims, characterized by that the thermally insulated space (10) is insulated from its immediate spatial surroundings in such a way that the heat loss is less than 5%, in particular less than 2%, based on the heat output of the device (1) for generating a gaseous fluid (41) in the form of steam. [4] Device (1) for generating a gaseous fluid (41) according to at least one of the preceding claims, characterized by that the device is designed to carry out natural circulation processes, forced circulation processes or forced throughflow processes, wherein the device in the embodiment for carrying out forced circulation processes or forced throughflow processes additionally comprises at least one pump (60) for conveying the liquid fluid (40). [5] Device for generating electrical energy (2), comprehensive a device (1) for generating a gaseous fluid (41) in the form of steam according to at least one of claims 1 to 4 and a power generation device (50) for converting the kinetic energy of the gaseous fluid (41) and / or the internal energy of the gaseous fluid (41) into electrical energy, characterized by , that the power generation device (50) is fluidically coupled to the device (1) for generating a gaseous fluid (41) in the form of steam in such a way that the gaseous fluid (41) can be supplied to the power generation device (50). [6] Device for generating electrical energy (2) according to claim 5, characterized by that the power generation device (50) comprises at least one turbine (51) for converting the energy of the gaseous fluid into mechanical work and at least one generator (52) for converting the mechanical work into electrical energy. [7] Device for generating electrical energy (2) according to claim 5 or 6, characterized by that the device comprises an equalizing vessel (54) for compensating pressure and / or volume fluctuations within flow-through components of the device for generating electrical energy (2). [8] Method for producing a gaseous fluid (41) in the form of steam by converting thermal energy, in which a device (1) for producing a gaseous fluid (41) in the form of steam according to at least one of claims 1 to 4 is provided and a gaseous fluid (41) is produced with this device. [9] Method for generating electrical energy, in which a device for generating electrical energy (2) according to at least one of claims 5 to 7 is provided and by means of this device the kinetic energy of the gaseous fluid (41) and / or the internal energy of the gaseous fluid (41) is converted into electrical energy.

Images