Plant for producing electric energy
The ORC plant integrates a centrifugal conveyor to transfer fluid without pumps, reducing height and operational costs by using vacuum and kinetic energy, and lubricates turboalternators with the fluid, addressing height and lubrication challenges while maintaining low temperatures.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- EUDOSIA SISTEMI
- Filing Date
- 2026-01-07
- Publication Date
- 2026-07-23
Smart Images
Figure IB2026050097_23072026_PF_FP_ABST
Abstract
Description
Plant for producing electric energyBackground of the invention
[0001] This invention relates to a plant for producing electric energy that is based on a so-called closed Organic Rankine Cycle (ORC) thermodynamic cycle, i.e. a closed thermodynamic Rankine Cycle , in which an organic fluid, derived from petroleum, is vaporized in a steam generator and used to feed the turbine of a turbo alternator, to generate electric energy, and then returns to liquid state in the steam generator.Prior art
[0002] In the prior art, plants are known for producing electric energy based on an ORC cycle, which comprise:- a combustion system that feeds a steam generator, in which an organic fluid derived from petroleum is vaporized;- a turboalternator that is supplied with the steam produced in the steam generator and generates electric energy;- a condenser in which the steam that supplied the turboalternator is condensed, to return to the steam generator,- an electric control system that adjusts the parameters of the energy produced, like, for example, the output voltage of the alternator, and, if requested, rectifies said output voltage, wherein the electric control system controls the start-up step of the turbo alternator and a possible emergency stop step.
[0003] The components of the plant are generally arranged on top of one another, with the steam generator placed in the lower part of the plant, the turbo alternator placed above the steam generator and, lastly, the condenser placed at the top of the plant.
[0004] In order to send the organic fluid condensed by the condenser to the steam generator, a pressure difference has to be overcome that is due to the temperature difference between the condensed organic fluid and the temperature of the organic fluid steam produced in the steam generator, a temperature difference that can be 100 °C or more.
[0005] The pressure difference can be overcome by exploiting the energy of gravity, i.e. by placing the condenser at a height with respect to the steam generator that is sufficient for the organic fluid in liquid state to be able to descend by gravity from the condenser to the steamgenerator overcoming the pressure difference between themselves. But this entails significant overall height dimensions of the plant.
[0006] Alternatively, it is possible to equip the plant with a pump, for example an electric pump, inserted into the hydraulic circuit that connects the condenser to the steam generator. This solution nevertheless entails energy consumption and can be a source of faults that can entail interruptions to the operation of the plant, for example if the pump has to be repaired or replaced.Summary of the invention
[0007] One object of this invention is to provide a plant for producing electric energy, of the type mentioned initially, based on a thermodynamic cycle ORC, which has reduced overall height dimensions and does not require the use of a pump to transfer the condensed organic fluid from the condenser to the steam generator.
[0008] A further object of this invention is to lubricate the bearings of the turboalternator without using a lubricating means fed by a separate lubricating system.
[0009] A still further object of this invention is to maintain a maximum temperature of the organic fluid in the plant relatively low.
[0010] The objects of this invention are achieved with a plant according to claim 1 and claims 2 to 8.Brief description of the drawings
[0011] Further advantages and features of the invention will be clear from the description that follows, with reference to the attached drawings in which:figure l is a schematic overall view of a plant according to the invention;figure 2 is an operating diagram of the plant according to the invention;figure 3 is a perspective view of a plant according to the invention, in which some parts have been removed in order to show the components of the plant better;figure 4 is an elevation view of the plant of figure 3;figure 5 is an enlarged detail of the plant according to the invention, which shows the turboaltemator;figure 6 is a view of the detail of figure 5, rotated by 180° with respect to figure 5; figure 7 is an exploded view of a further detail of plant according to the invention.With reference to the figures, a plant 1 according to the invention comprises a support and containing structure 2, to which a combustion system 3 is fixed, comprising, for example, a gas burner, which feeds thermal energy to a steam generator 4 in which an organic fluid derived from petroleum is evaporated until it reaches steam state. The combustion system 3 is equipped with an exhaust flue 32 for the fumes produced by burning the fuel used.
[0012] The organic fluid exits the pressurized steam generator 4 in steam state and enters a first conduit 10 that conveys the organic fluid in overheated steam state to a turboalternator 5.
[0013] The turboaltemator 5 comprises a turbine 6, which is driven by the organic fluid in steam state, and an alternator 7, which is coaxial with the turbine 6, which is driven by the turbine 6, to produce electric energy.
[0014] The organic fluid in steam state, after traversing the turbine 6, is sent to a condenser 8, via a second conduit 11 that connects an outlet of the turbine 6 to an inlet of the condenser 8.
[0015] The organic fluid condenses in the condenser 8, passing from steam state to liquid state to then return to the steam generator 4. The condenser 8 is equipped with a collecting tank 23 for collecting the organic fluid.
[0016] The combustion system 3, the steam generator 4, the turboalternator 5 and the condenser 8 are arranged aligned vertically, i.e. in a direction parallel to the direction of the force of gravity.
[0017] All the components of the plant, except for the condenser 8, are enclosed in a casing 9.
[0018] In order to be able to return from the condenser 8 to the steam generator 4, the organic fluid in liquid state has to overcome a pressure difference that exists between the outlet of the condenser 8 and an inlet of the steam generator 4. This pressure difference is due to the temperature difference existing between the outlet of the condenser and the steam generator. For example, the temperature at the outlet of the condenser can be about 80 °C, whereas the temperature in the steam generator can reach 190 °C.
[0019] The organic fluid in liquid state, which on exiting the collecting tank 23 of the condenser 8 enters a third conduit 12, enters a first filter 21, which filters possible impurities present in the organic fluid, exits the first filter 21 and reaches an inlet connection 15 of a centrifugal conveyor 14 via a fourth conduit 13.
[0020] In the plant 1, a vacuum is created, in particular in the closed circuit of the organic fluid, and thus in the steam generator 4, in the turboalternator 5, in the condenser 8 and in the conduits 10-13, so as to make the plant 1 operate in a vacuum. This enables the maximum temperature of the organic fluid inside the plant 1, i.e. in the steam generator 4, to be kept low, for example not above about 200 °C.
[0021] The centrifugal conveyor 14 is integrated into the turboaltemator 5, wherein the centrifugal conveyor 14 comprises a first part 14a fixed to the rotor 26 of the turbine 6, and a second part 14b fixed to a frontal flange 28 of the turboaltemator 5.
[0022] Inside the first part 14a of the centrifugal conveyor 14 a chamber 29 is defined into which the organic fluid in liquid state is delivered, via the inlet connection 15, which engages a first inlet hole 15a obtained in the second part 14b of the centrifugal conveyor 14 and communicating with a second inlet hole 15b obtained in the frontal flange 28.
[0023] The organic fluid in liquid state delivered to the chamber 29 acquires kinetic energy, through the effect of the rotation of the first part 14a, fixed to the rotor 25 of the turbine 6, taking advantage of the rotation of the rotor 25.
[0024] The rotor 25, which is fixed to the shaft 24 of the turboalternator 5, is rotated by the organic fluid in steam state that, coming from the steam generator 4, hits the blades 26 of the rotor 25.
[0025] The organic fluid in liquid state, after acquiring kinetic energy, exits the chamber 29 by entering a first end 30 of a stationary outlet conduit 27, the second end 31 of which traverses a first outlet hole 16b, obtained in the frontal flange 28 of the turboalternator 5, and engages a second outlet hole 16a, obtained in the second part 14b of the centrifugal conveyor 14, wherein the outlet connection 16 also engages the second outlet hole 16a and is connected to a fifth conduit 17, which conveys the organic fluid to the steam generator 4.
[0026] The centrifugal conveyor 14, taking advantage of the rotation of the turboalternator 5, acts as a centrifugal pump, conferring energy to the organic fluid so that the organic fluid can overcome the pressure difference between the condenser 8 and the steam generator 4.
[0027] Using the centrifugal conveyor 14 enables the use to be avoided of an electric pump that is used in plants known from the prior art, which would entail energy consumption and would further require complex operations for possible repairs or replacements because the plant 1 according to the invention operates in a vacuum. Said operations would entail lengthy plant downtime and high costs.
[0028] Further, using the centrifugal conveyor 14 enables the overall height dimensions of the plant to be limited, which would be significant if it were desired to avoid using a pump by exploiting gravity energy to enable the condensed organic fluid in the condenser 8 to overcome the existing pressure difference between the condenser 8 and the steam generator 4.
[0029] The organic fluid in liquid state condensed in the condenser 8 is used to lubricate the bearings of the turboaltemator 5. For this purpose, the organic fluid in liquid state is bled from the collecting tank 23 of the condenser 8, by a bleed conduit 18, sent to a second filter 22, having a function that is similar to that of the first filter 21 and conveyed to the front and rear bearings of the shaft of the turboalternator 5 via a sixth conduit 19 and a seventh conduit 20, respectively.
[0030] The organic fluid forms, inside the aforesaid bearings, a hydrodynamic film between the bearings and the pins of the shaft of the turboaltemator 5 that are inserted into said bearings. During rotation of the shaft of the turboalternator 5, the pins fluctuate on the hydrodynamic film with negligible friction resistance. This makes high rotation speeds of the turboalternator with minimal pin wear possible.
[0031] The temperature of the organic fluid sent to the bearings of the turboaltemator 5 is monitored, for example by temperature sensors, to prevent the organic fluid being able to reach excessively high temperatures, which would cause the hydrodynamic film to evaporate. Also, the steam temperature inside the steam generator 4 is monitored, to prevent carbonization of the organic fluid.
[0032] Using the organic fluid to lubricate the bearings of the turboalternator enables the need for a lubricating means with a corresponding lubricating circuit to be eliminated, thus obtaining a reduction in the costs and constructional complexity of the plant 1 according to the invention.
[0033] The vacuum is also achieved inside the conduits 17-20, 27, because such conduits are part of the closed circuit of the organic fluid.
Claims
1. CLAIMS1. Plant for producing electric energy (1), comprising:- a combustion system (3), configured to produce thermal energy,- a steam generator (4) supplied by the thermal energy produced by the combustion system (3) and configured to produce steam from an organic fluid derived from petroleum,- a turboaltemator (5) that comprises a turbine (6), driven by said steam of said organic fluid, and an alternator (7) driven by the turbine (6) and configured to produce electric energy, and- a condenser (8) in which the organic fluid in steam state, coming from the turbine (6), condenses, passing from steam state to liquid state,characterized in that it further comprises a centrifugal conveyor (14), which is integrated into the turboaltemator (5), wherein the organic fluid in liquid state condensed in said condenser (8) is sent to said centrifugal conveyor (14), which confers energy to the organic fluid in liquid state, taking advantage of the rotation of the turboaltemator (5), and conveys the organic fluid in liquid state to said steam generator (4) overcoming a pressure difference between the condenser (8) and the steam generator (4).
2. Plant (1) according to claim 1, wherein the centrifugal conveyor (14) comprises a first part (14a), fixed to a rotor (25) of the turbine (6) of the turboaltemator (5) and a second part (14b) fixed to a frontal flange (28) of the turboalternator (5).
3. Plant (1) according to claim 2, wherein in said first part (14a) of the centrifugal conveyor (14) a chamber (29) is defined into which the organic fluid in liquid state coming from the condenser (8) is delivered and from which said organic fluid exits, after acquiring kinetic energy by taking advantage of the rotation of the turboaltemator (5), to be sent to the steam generator (4)4. Plant (1) according to one of claims 1 to 3, wherein a portion of said organic fluid in liquid state is bled from said condenser (8) and conveyed to bearings of a shaft (24) of the turboaltemator (5), to create a hydrodynamic film between the bearings and pins of the shaft (24) of the turboalternator (5) inserted into said bearings.
5. Plant (1) according to one of the preceding claims, further comprising a first filter (21) through which the organic fluid in liquid state coming from said condenser (8) is passed before reaching the centrifugal conveyor (14).
6. Plant (1) according to claim 4, or 5, further comprising a second filter (22) through which the portion of organic fluid bled from the condenser (8) is passed, before reaching the bearings of the shaft (24) of the turboalternator (5).
7. Plant (1) according to one of claims 4 to 6, further comprising temperature sensor means configured to measure a temperature of said portion of organic fluid.
8. Plant (1) according to one of the preceding claims, wherein the combustion system (3), the steam generator (4), the turboalternator (5) and the condenser (8) are aligned vertically.
9. Plant (1) according to one of the preceding claims, further comprising a support and containing structure (2), to which the combustion system (3), the steam generator (4), the turboalternator (5) and the condenser (8) are fixed.
10. Plant (1) according to one of the preceding claims, wherein the combustion system (3), the steam generator (4) and the turboalternator (5) are enclosed in a casing (9).
11. Plant (1) according to one of the preceding claims, wherein in a closed circuit of the organic fluid, comprising the steam generator (4), the turboalternator (5) and the condenser (8) a vacuum is created.