WO2019138352A1

WO2019138352A1 - System for generating electricity that uses a magnetohydrodynamic assembly

Info

Publication number: WO2019138352A1
Application number: PCT/IB2019/050189
Authority: WO
Inventors: Daniel GASPERINI
Original assignee: Zuccato Energia S.R.L.
Priority date: 2018-01-11
Filing date: 2019-01-10
Publication date: 2019-07-18
Also published as: IT201800000756A1

Abstract

The system (1000) for generating electricity comprises a magnetohydrodynamic generator (100) assembly; the assembly (100) comprises: a magnetohydrodynamic generator (10) having a generator inlet (11) for fluid and a generator output (12) for fluid, an ioniser (20) having an ioniser inlet (21) for fluid and an ioniser outlet (22) for fluid, said ioniser outlet (22) being fluidically connected to said generator inlet (11), and a working fluid; the ioniser (20) is adapted to ionise said working fluid that flows from said ioniser inlet (21) to said ioniser outlet (22), and comprises at least one preferably supersonic convergent-divergent nozzle (23A... 23D) that is traversed by said working fluid; said working fluid contains water, in particular it is made of water or of an aqueous solution.

Description

System for generating electricity that uses a magnetohydrodynamic assembly

DESCRIPTION

FIELD OF THE INVENTION The present invention relates to a system for generating electricity that uses a magnetohydrodynamic assembly.

STATE OF THE ART

Magnetohydrodynamic generators have been known for quite some time. They are apparatuses which an ionised fluid enters; the ions of the fluid are deviated by a magnetic field and they end on electrodes, thus generating a potential difference and hence electricity.

However, magnetohydrodynamic generators have not become widely used because, in known solutions, creating an ionised fluid was a complicated and costly operation for various reasons. SUMMARY

The general purpose of the present invention is to provide a solution for creating an ionised fluid in a simple, effective and efficient way, in particular an ionised biphase fluid, more in particular a biphase fluid with both phases ionised.

The ionised fluid must be made of a substance (or of a mixture of substances) that is easy to find, economical and, possibly, non-toxic.

This purpose is achieved thanks to what is set forth in the claims that are an integral part of the present description.

A first important idea for the present invention is that the ionised fluid is obtained making a (non-ionised) fluid pass through at least one nozzle, in particular a preferably supersonic convergent-divergent nozzle.

A second important idea for the present invention is that the ionised fluid is made of water or contains water, in particular the water content is preponderant with respect to any other components (greater than 60%, more in particular greater than 70%, still more in particular greater than 80%, and yet more in particular greater than 90%).

LIST OF FIGURES

The present invention shall become more readily apparent from the detailed description that follows to be considered together with the accompanying drawings in which:

Fig. 1 shows a block diagram of an example of embodiment of a system according to the present invention,

Fig. 2 shows a schematic section view of an example of embodiment of an assembly according to the present invention,

Fig. 3 shows a simplified T-S diagram of a first possible thermodynamic cycle implementable by the system of Fig. 1,

Fig. 4 shows a simplified T-S diagram of a second possible thermodynamic cycle implementable by the system of Fig. 1,

Fig. 5 shows a simplified T-S diagram of a third possible thermodynamic cycle implementable by the system of Fig. 1, and

Fig. 6 shows a simplified T-S diagram of a fourth possible thermodynamic cycle implementable by the system of Fig. 1.

As is easily understandable, there are various ways of implementing in practice the present invention which is defined in its main advantageous aspects in the appended claims. The embodiment examples described below should not be considered limiting of the present invention. DETAILED DESCRIPTION

Fig. 1 shows an example of embodiment of the present invention, i.e. a system 1000 for generating electricity based on a magnetohydrodynamic assembly 100. The assembly 100 comprises a magnetohydrodynamic generator 10 and an ioniser 20.

The system 1000 further comprises, advantageously, a vapour generator 30 (more in general, a "heater"), a vapour condenser 40 (more in general, a "condenser") and a pump 50, connected in a loop with the assembly 100, as well as an electrical converter 60. In the system 1000 a working fluid circulates, that is subject to thermodynamic transformations in the components of the system 1000 that are connected in a loop, i.e. the magnetohydrodynamic generator 10, the ioniser 20, the vapour generator 30, the vapour condenser 40 and the pump 50.

During the operation of the system 1000, from an electrical output 13 of the magnetohydrodynamic generator 10 exits a direct current electrical signal that enters an electrical input 61 of the converter 60, for example an AFE (Active Front End) power converter; the converter 60 transforms the direct current electrical signal, for example, into an alternating current electrical signal and provides it to an electrical output 62 thereof. The voltage of the direct current electrical signal can vary over time and depends, inter alia, on the operation of the components of the system 1000 that are connected in a loop.

According to alternative embodiments of the system to that of Fig. 1, the system could, for example, not comprise an electrical converter if the electrical signal at the output of the magnetohydrodynamic generator is already suitable for powering the expected electrical user device.

Hereafter, the term "inlet" shall mean an "inlet for fluid", the term "outlet' shall mean an "outlet for fluid", and the term "connected" shall mean "fluidically connected".

The working fluid enters from an inlet 11 of the magnetohydrodynamic generator 10 and exits from an outlet 12 of the magnetohydrodynamic generator 10, enters from an inlet 41 of the vapour condenser 40 and exits from an outlet 42 of the vapour condenser 40, enters from an inlet 51 of the pump 50 and exits from an outlet 52 of the pump 50, enters from an inlet 31 of the vapour generator 30 and exits from an outlet 32 of the vapour generator BO, enters from an inlet 21 of the ioniser 20 and exits from an outlet 22 of the ioniser 20. The outlet 12 is fluidically connected to the inlet 41, the output 42 is fluidically connected to the input 51, the output 52 is fluidically connected to the inlet 31, the outlet 32 is fluidically connected to the inlet 21, the outlet 22 is fluidically connected to the inlet 11.

The vapour generator 30 is adapted to generate at the outlet 32 a working fluid typically at high temperature and at high pressure; more in general, the component 30 can be a "heater".

The component 40 is adapted to "condense" vapour contained in the working fluid that enters the component itself, i.e. to transform it into a liquid.

The ioniser 20 is adapted to ionise the working fluid that flows from the inlet 21 to the outlet 22 making it pass through at least one nozzle - Fig. 2 shows a particularly advantageous example of embodiment of said ioniser. The ioniser 20 exploits in particular the phenomenon called "steam electricity" or "spray charging". The ioniser 20 is adapted to generate at the output a biphase fluid typically at higher temperature and at high pressure. Typically, if the fluid is made of water (or almost totally of water) the temperature is lower than 192°C and the pressure is lower than 1.2 MPa.

Preferably, the working fluid is made of water or of an aqueous solution. In the system 1000 of Fig. 1, the vapour condenser is fluidically connected to the vapour generator 30 so as to accomplish a thermodynamic cycle. The figures Fig. 3, Fig. 4, Fig. 5 and Fig. 6 show T-S diagrams of four possible (realistic) thermodynamic cycles implementable by the system 1000 of Fig. 1.

Typically, the working fluid that enters the vapour generator 30 is all liquid. Typically, the working fluid that exits from the vapour condenser 40 is all liquid. As can be understood from Fig. 3, the working fluid that enters the ioniser can be all liquid - point 301 in the figure (limit case); in this case, the vapour generator 30 heats the incoming liquid until it starts its transformation from liquid to vapour. The output conditions from the ioniser correspond to point 302 in the figure and correspond to a biphase fluid.

As can be understood from Fig. 4, the working fluid that enters the ioniser can be all gas, in particular saturated vapour - point 401 in the figure (limit case); in this case, the vapour generator 30 heats the incoming liquid until it ends its transformation from liquid to vapour. The output conditions from the ioniser correspond to point 402 in the figure and correspond to a biphase fluid.

As can be understood from Fig. 5, the working fluid that enters the ioniser can be a mixture of liquid and gas - point 501 in the figure; naturally, the liquid/gas percentage can vary on a case by case basis. The output conditions from the ioniser correspond to point 502 in the figure and correspond to a biphase fluid. As can be understood from Fig. 6, the working fluid that enters the ioniser can be all gas, in particular superheated vapour - point 601 in the figure; in this case, the generator 30 superheats the incoming liquid until it ends its transformation from liquid to vapour. The output conditions from the ioniser correspond to point 602 in the figure and correspond to a biphase fluid. According to embodiments of the system alternative to that of Fig. 1, the system could, for example, not implement a thermodynamic cycle, i.e., in other words, implement an "open thermodynamic cycle"; this applies in particular if the system is used to exploit geothermal energy.

In the case of "open thermodynamic cycle", too, a first advantageous feature of the system is to comprise a vapour generator fluidically connected upstream of the ioniser. The generator could for example use a flow of energy and/or mass of geothermal nature. In the case of "open thermodynamic cycle", too, a second advantageous feature of the system is to comprise a vapour condenser fluidically connected downstream of the magnetohydrodynamic generator. In this way, no hot vapour is dispersed into the atmosphere. Below, with the aid of Fig. 2, is described an example of magnetohydrodynamic assembly 100 that is particularly advantageous to process a working fluid (see the arrows in the figure).

It should be noted that in the system 1000 of Fig. 1, a different assembly from that of Fig. 2 can be used. The assembly 100 comprises a ioniser 20 and a magnetohydrodynamic generator 10 fluidically connected downstream of the ioniser 20 through an exhaust diffuser 70; Fig. 2 shows that the ioniser 20 has an inlet 21 (for example with circular shape) and an outlet 22 (for example with circular shape), that the magnetohydrodynamic generator 10 has an inlet 11 (for example with rectangular shape) and an outlet 12 (for example with rectangular shape), and that the output 22 is fluidically connected to the inlet 11 through exhaust diffuser 70 having a duct 74 that also serves as a coupling (for example from the circular shape to the rectangular shape); preferably, the duct 74 is made of electrically insulating material.

The ioniser 20 comprises at least one nozzle, preferably a convergent-divergent nozzle, still more preferably a convergent-divergent supersonic nozzle; the working fluid traverses the nozzle and the ionisation of the fluid takes place in the terminal portion of the nozzle.

It should be noted that a convergent-divergent nozzle is conceptually divided in three portions: an initial portion that is convergent, a terminal portion that is divergent and an intermediate portion (that can be very short) with substantially constant section. In a nozzle according to the present invention, these three portions can be variously shaped (in particular they can have various lengths) and positioned (in particular, they can have various mutual distances). In a nozzle according to the present invention, for example, the convergent portion can consist of one or more components, the constant portion (if present) can consist of one or more components, the divergent portion can consist of one or more components. A nozzle according to the present invention, or an equivalent device, is adapted to accelerate the incoming fluid and then to expand it efficiently; in this way, in a fluid with humid isentropic expansion, for example water (or mixtures thereof), it is possible to obtain a fine nucleation and dispersion of the liquid phase. In the case of water (or mixtures thereof) for example, it is possible to obtain a transitional ionisation with charges of opposite signs distributed between the liquid phase and the gaseous phase, creating, de facto, a "cold plasma". The intensity of the ionisation is proportional to the enthalpic change processed by the nozzle (or an equivalent device) and to the expansion efficiency. Given the transitional nature of the ionisation (the charges naturally tend to cancel each other out), it is preferable that the ionisation system be positioned as close as possible to the magnetic charge separator.

In the example of Fig. 2, the ioniser 20 comprises, for example, four convergent-divergent nozzles 23A, 23B, 23C and 23D fluidically connected in series; in particular, all these nozzles are supersonic. It could be thought that the connection of multiple nozzles in series is needless because the ionisation caused with the expansion is cancelled out by the subsequent compression; however, the Applicant's experiments have shown that connecting multiple nozzles in series allows to obtain a greater ionisation with respect to a single nozzle.

In Fig. 2, the nozzles 23A, 23B, 23C and 23D are all identical; alternatively, they could be different, in particular all different. The nozzles of the ioniser are of electrical insulating material and they are inserted in a casing 24 that can be, for example, of metallic material.

The magnetohydrodynamic generator 10 comprises a plurality of permanent or electrical magnets (known as "electromagnets"); in Fig. 2, there is a first set of higher magnets 16A and a second set of lower magnets 16B. The magnets are outside a casing 14, of electrical insulating material, in which the working fluid flows.

Inside the casing 14, there is at least one pair of electrodes (only the electrode 15A is shown in the figure) on which the ions of the ionised fluid impact by effect of the magnetic field of the magnets 16A and 16B; in general, there can be various pairs of electrodes, variously shaped and arranged to optimise the generation function of the magnetohydrodynamic generator 10.

From the above, it is understood that the present invention achieves its set purposes.

Claims

1. System (1000) for generating electricity, comprising a magnetohydrodynamic assembly (100);

wherein said assembly comprises:

- a magnetohydrodynamic generator (10) having a generator inlet (11) for fluid and a generator outlet (12) for fluid,

an ioniser (20) having an ioniser inlet (21) for fluid and an ioniser outlet (22) for fluid, said ioniser outlet (22) being fluidically connected to said generator inlet (11), and

- a working fluid;

wherein said ioniser (20) is adapted to ionise said working fluid that flows from said ioniser inlet (21) to said ioniser outlet (22), and comprises at least one preferably supersonic convergent-divergent nozzle (23A ... 23D) that is traversed by said working fluid,

wherein said working fluid contains water, in particular it is made of water or of an aqueous solution.

2. System (1000) according to claim 1, wherein said magnetohydrodynamic generator (10) comprises a plurality of permanent magnets or of electromagnets (16A, 16B).

3. System (1000) according to claim 1 or 2, wherein said magnetohydrodynamic generator (10) comprises at least one pair of electrodes (15A).

4. System (1000) according to claim 1 or 2 or 3, comprising a plurality of convergent- divergent nozzles (23A ... 23D) fluidically connected in series, all the nozzles (23A ... 23D) of said plurality being preferably supersonic.

5. System (1000) according to claim 4, wherein the nozzles (23A ... 23D) of said plurality are equal to or different from each other.

6. System (1000) according to any of the claims from 1 to 5, wherein said working fluid is all liquid at said ioniser inlet (21) (Fig. S) and said ioniser (20) is adapted to provide at said ioniser outlet (22) an ionised biphase fluid, in particular with both phases ionised.

7. System (1000) according to any of the claims from 1 to 5, wherein said working fluid is all gas at said ioniser inlet (21) (Fig. 4) and said ioniser (20) is adapted to provide at said ioniser outlet (22) an ionised biphase fluid, in particular with both phases ionised.

8. System (1000) according to any of the claims from 1 to 5, wherein said working fluid is a mixture of liquid and gas at said ioniser inlet (21) (Fig. 5) and said ioniser (20) is adapted to provide at said ioniser outlet (22) an ionised biphase fluid, in particular with both phases ionised.

9. System (1000) according to any of the preceding claims, further comprising a heater (30) fluidically connected upstream of said ioniser (20) and adapted to generate at the outlet superheated working fluid and to provide it to said ioniser inlet (21), said heater being in particular a vapour generator (30).

10. System (1000) according to claim 9, in said ioniser (20) and adapted to generate at the outlet superheated working fluid at a temperature lower than 192°C.

11. System (1000) according to claim 10, in said ioniser (20) and adapted to generate at the outlet superheated working fluid at a pressure lower than 1.2 MPa.

12. System (1000) according to any of the preceding claims from 1 to 11, further comprising a vapour condenser (40) fluidically connected downstream of said magnetohydrodynamic generator (10).

13. System (1000) according to claims 9 and 12, wherein an outlet of said vapour condenser (40) is fluidically connected to an inlet of said heater (30) so as to accomplish a thermodynamic cycle.

14. System (1000) according to claim 13, wherein said thermodynamic cycle is closed.

15. System (1000) according to any of the preceding claims from 1 to 13, adapted to accomplish an open thermodynamic cycle.