ES2632109A1 - Device for the impulsion of fluids at a very high temperature (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

Device for driving fluids at a very high temperature. Device through which all the mass flow of a main pipe, or a fraction of said flow, circulates, and is cooled in a regenerative exchanger, and subcooled in an auxiliary cooler, after which it passes to a driving machine that raises the fluid pressure downstream of the device, after discharge of the device flow into the main pipeline. (Machine-translation by Google Translate, not legally binding)

Description

DEVICE FOR IMPULSION OF FLUIDS AT VERY HIGH TEMPERATURE

DESCRIPTION

SECTOR OF THE TECHNIQUE 5

The invention falls within the field of thermal engineering, particularly in applications that are based on circuits or conduits, through which a fluid circulates at a very high temperature, this term meaning a thermal level above what they can withstand, without loss of performance or loss of characteristics, common materials such as carbon steel, aluminum or copper. 10

TECHNICAL PROBLEM TO BE RESOLVED AND BACKGROUND OF THE INVENTION

The problem of boosting fluids at a very high temperature, which in general are in a gaseous state, comes from a double difficulty: on the one hand, the purely thermodynamic, since high temperatures are accompanied by high values in the specific volume, or molar volume , which forces very large machines; and the technical difficulty, because conventional or commercially available materials cannot be used in pumps or compressors, but rather very expensive alloys must be used, which also require careful control and maintenance, as is the case with motor compressors Aeronautical These are justified in price and requirements by the uniqueness of their mission, the environment in which they work, the importance of their safety and the service they provide. However, in a solar thermal power plant that uses gas as a heating fluid, a very high pumping power will be required, and the drive machines will be unacceptably expensive if the aeronautical compressor guidelines are to be followed. 25

The problem is generally addressed in thermal engineering with a recipe based on thermodynamics and fluid mechanics, but somewhat simplistic, which says that the driving machines have to be located, if no other restrictions appear, in the lower parts and cooler circuits or installations. This is because the 30 driving machines work better, and even much better, the more primed they are, that is, the more packed with molecules of the fluid in question, which is achieved with the aforementioned recipe, which logically does not constitute a documented precedent. , but a reference to how popular knowledge materializes what are actually properties of the fluid state equations.

As representative documents, which in themselves are not a direct precedent to the device presented here, but deal with related issues, one can cite precisely 5 grouped by themes. GB2366333 (A) and US3360193 (A) present regenerative multi-stage compressors. Although the device explained here also has a regenerative component (for obvious reasons of not wasting heat) this quality cannot be considered as the basis from which the device can be imagined. Thermal regeneration is a common arrangement in heat exchanges between the same fluid in two different thermodynamic situations, and is intended to recover the heat transmitted in an intermediate stage. As such, thermal regeneration is not the root of the invention, as will be seen.

There are, for example, refrigeration and air conditioning devices incorporating 15 compressors and thermal regeneration elements, such as JPH0926182 (A); JP2001227837 (A) and JP2001296068 (A). An interesting variant, but one that does not precede the invention of this application, is the regenerative heat pump of CN202613753 (U).

 twenty

Finally, the compressed air handling device of document US2011127004 (A) should be mentioned as an example of the state of the art for storing high pressure fluids (for energy storage, for example)

EXPLANATION OF THE INVENTION 25

The invention takes advantage of the thermodynamic properties of fluids, which are more pronounced in gases, for which it is relatively easy to compress a fluid substance when it is cold, and much more difficult when it is very hot. And the issue of difficulty can be measured in energy consumed for compression, and in shortage of used machinery. The invention is the materialization of a physical idea, which is to condition the fluid from its thermodynamic state, to another that is optimal for compression; make this one; and ensure its impulse effect on the fluid, without final depletion of its thermal conditions.

The invention is implanted in a pipe or conduit of fluid, to which an increase in pressure, also called manometric height, must be communicated, so that, maintaining its mass flow, or fluid expenditure, expressible in kilograms per second, the pressure of the fluid in the pipe downstream of the device is greater than the pressure of the fluid upstream of the device; for which the invention consists of:

- a fluid intake from inside the main pipe, said intake being made through the mouth of the device conduit in its first section, said conduit leaving the interior of the main pipe through a hermetic periphery hole, or fusing of the first stretch;

- a fluid flow control valve captured from the main pipeline, said valve being located in the first section of the device, said first section covering until it enters the regenerative exchanger, on the lower pressure side;

- a regenerative heat exchanger, in which there is a low pressure line, in which the primary fluid, coming from the main pipe, cools, releasing heat, through intermediate walls, to the higher pressure fluid, and lower temperature, which heats up, and comes from the drive mouth of the drive machine of the device; leaving the primary or lower pressure fluid from the regenerative exchanger, to go, through a second section of conduction to the auxiliary refrigerator; twenty

- said auxiliary refrigerator being an exchanger with a cold fluid current that comes from the outside of the device, and cools the fluid of the device to the temperature to which this auxiliary refrigerator is adjusted, from which the device fluid emerges at a temperature designated for the performance of the driving machine in which it enters from the exit of this auxiliary refrigerator; 25

- this driving machine being a pump, a compressor, or a circulator in general, which gives the device fluid greater pressure, greater speed, or both; said fluid emerging from a conduit that enters as a secondary fluid in the regenerative heat exchanger, heating;

- and its temperature is further increased after the previous step, by an auxiliary heating exchanger, whose heating fluid comes from a source of heat outside the device;

- the fluid of the device being channeled through a last section conduit, which enters the main tube through an airtight flush, reaching the device's fluid discharge mouth: 35

- in whose vicinity downstream there is a venturi, or reduced straight section passage with respect to the original of the main tube, after which passage the straight section is reopened until the original section of the main tube is recovered.

The fraction of the main fluid that is diverted towards the device of the invention can be any, always above zero, and reaching 1. Thus, as a singular variant, the device is completely in series between the upstream and downstream of the main line, passing all the main line fluid through the device.

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EXPLANATION OF THE FIGURES

The figures, in general, are not to scale, since the relative sizes of the elements are very different; but they are representative of the invention and its operating principles.

 fifteen

Figure 1 shows a longitudinal scheme of the device, which includes all the substantive elements of the invention.

Figure 2 shows the longitudinal scheme of an assembly that is the extreme case of the invention, in which all the flow of the fluid passes through the device. twenty

Figure 3 shows the thermodynamic graph of the evolutions that occur in an assumption with air, in a diagram in which the horizontal lines are isóbaras and the vertical ones are isálálpicas.

 25

In order to facilitate the understanding of the figures of the invention, and of their embodiments, the relevant elements thereof are listed below:

1. Main or original duct where a high temperature fluid circulates.

2. Straight section of the main duct 1, upstream of the device.

3. Fluid intake, in the main duct, to bring that fraction of fluid to the device.

4. Valve that regulates the passage of fluid to the device.

5. Regenerative heat exchanger, in which the fluid of the device passes twice, sequentially, first as a fluid at relatively low pressure, and hot, so it cools, and then at higher pressure, but colder, so It heats up. 5

6. Device fluid inlet tube in the regenerative heat exchanger. Figure 3 shows a thermodynamic diagram in which there are several labels, all finished in T, and are the concretion, in said diagram, of the thermodynamic conditions of said point or line; and in particular, the 6T label, which corresponds to item 6. 10

7. For the first time, the fluid from the device exits the regenerative heat exchanger, at a lower temperature than in the input 6. 7T represents the thermodynamic conditions of point 7.

8. Auxiliary cooling heat exchanger.

9. Fluid duct of the device, in which it is cooled further, as it passes through the auxiliary exchanger 8.

10. External auxiliary refrigerant inlet in exchanger 8.

11. External auxiliary refrigerant outlet from the exchanger 8.

12. Duct that carries the fluid from the device to the pump, compressor or circulator in general, at low temperature with respect to the original circulating fluid by 1. 20 point 12T represents the thermodynamic conditions of point 12.

13. Pump, compressor or circulator in general, which drives the fluid of the device, increasing its pressure, its speed, or both magnitudes.

14. Supply pipe through which the fluid flows out of the circulator 13 and crosses the regenerative exchanger 5, heating. Point 14T represents the 25 thermodynamic conditions of point 14. Point 14a marks the output of that exchanger, in the high pressure pipe. Point 14aT represents the thermodynamic conditions of point 14a.

15. Auxiliary heat exchanger for heating the fluid of the device.

16. External auxiliary heating fluid inlet in exchanger 15. 30

17. External auxiliary heating fluid outlet from the exchanger 15.

18. Device tube, continuation of 14, through which fluid flows from the device to be injected back into the main tube 1.

19. Device fluid discharge port in the main stream of the tube 1, downstream. Point 19T represents the thermodynamic conditions of point 19. 5

20. Main flow section, in tube 1, downstream of the device.

21. Flow stabilizing partition and support for the longitudinal mechanical reactions of the intake and discharge nozzles of the device.

22. Venturi for mixing the device flow with the rest of the original flow, downstream of the device. 10

23. Fogonadura or hermetic hole of passage through the wall of the main conduit (1) of the tube of the device in its first section.

24. Fogonadura or hermetic hole of passage through the wall of the main conduit (1) of the tube of the device in its last section.

25. Real compression on the drive machine (13). It is only represented as 25T, 15 in the diagram of Figure 3.

26. Cooling of the fluid in the regenerative exchanger. It is only represented as 26T.

27. Heating of the fluid in the regenerative exchanger, already at high pressure. It is only represented as 27T. twenty

28. Straight, which along with its parallel 29, marks the enthalpy transfer of the fluid that follows evolution 26 to that of 27. It is only represented as 28T.

29. Parallel to 28. It is only represented as 29T.

30. Hypothetical compression that would have happened if a driving machine had been applied to the original fluid. It is only represented as 30T. 25

31. End point of hypothetical compression 30. Only represented as 31T.

32. Vertical straight of equal enthalpy. It is only represented as 32T.

EMBODIMENT OF THE INVENTION

The invention is implanted in a conduit (1) of a very hot fluid which must be provided with a greater pressure so that it can complete its trajectory in any system. By very hot fluid it is to be understood that its temperature exceeds the conventional one of the driving machines of that fluid, which is mostly limited 5 so that they support the seals, especially around shafts.

To materialize the device there is a conventional driving machine (13), which is the center of the device; and it is connected by its entrance upstream of the main tube by the first section (3) of the device, which enters inside the main tube by means of a hermetic seal (23); said first section being provided with a valve (4) for regulating the passage of fluid to the device.

On the way from the first section to the entrance of the driving machine the fluid passes through the regenerative exchanger (5) in which it enters through a conduit (6) 15 that is at a temperature equal to that of the fluid in the main tube (1), and exits (5) through the conduit (7) at a lower temperature, for having transmitted heat to a secondary fluid, which is the device's own fluid at the outlet (14) of the driving machine (13).

To precisely adjust the temperature conditions of the fluid to the machine itself, an auxiliary cooler (8) is available that is cooled with an outside source (air, water, ...) that enters the duct (10) into the auxiliary cooling exchanger (8) and exits through (11) cooling the working fluid, which circulates through the internal conduit (9) of the refrigerator (8).

 25

The driving machine then works properly and provides a drive M, which is the difference in total pressures between its outlet (14) and its inlet (12) while also maintaining the same mass flow, or expense, that had been captured by the mouth of water above (3). The total pressure is the sum of the static pressure (the one marked by the pressure gauge) and the dynamic pressure, which is half the density multiplied by the 30 square of the velocity. The straight section of the output of the device (19) is reduced all the more the higher the speed through said output, which in turn implies a greater separation between said output (19) and the venturi (22).

The output speed can be kept equal to that of the drive machine, if the straight output section is reduced in the same proportion as the specific volume of the fluid is reduced. In this case, the entire drive will increase the outlet pressure in the tube (14) that we can consider in two mounting variants:

- That increases its straight section as its specific volume increases when the fluid is heated as it passes through the regenerative exchanger (5) and just after when it finishes heating to the same temperature as the main fluid in the tube (1) upstream (2).

- That does not vary in diameter until its exit to the flow of the main tube (1), whereby the fluid accelerates, due to an increase in its specific volume.

To accommodate the conversion of kinetic energy to pressure energy, accelerating the fluid that has remained in the main tube (1) before said conversion, a venturi (22) is available, the outlet of which leads to a main tube (20) of the same straight section as the upstream, with equal speed, but with greater pressure.

The type of driving machine and its working conditions will depend on the type of fluid considered, basically if it is incompressible or compressible; although the assembly of the device will be essentially the same. twenty

In the case of the incompressible, essentially liquid, the isentropic evolutions, which are those that theoretically describe the evolutions in the driving machines, are almost analogous to the isenthalic, so that in a compression of an incompressible fluid, the increase in pressure It involves a very small increase in temperature, and a negligible variation in density. On the contrary, compressible fluids, such as ideal gases, have isentropic lines that are very divergent from isenthalpy, so that when the gas is compressed from pressure level P1 to level P2, enthalpy (specific) increases by a ΔH value which is about 30 worth

ΔH = (P2-P1) / ρ

Where ρ is the value of the average density, which is approximately valid, depending on the specific volumes of the beginning of compression, V1, and the end, V2,

1 / ρ = 2 · V1 · V2 / (V1 + V2)

When the V2 at the end of the compression is much smaller than V1, the enthalpy increase equation is

ΔH = (P2-P1) · 2 · V2

In this compression if there is a significant increase in temperature, even 5 under ideal conditions, and it is

T2-T1 = ΔH / Cp

Cp being the specific heat at constant pressure. This coefficient does not depend on the pressure in the ideal gases, except when approaching the critical isobar, in which it exhibits a very unique behavior, which includes a Cp value that becomes asymptotically infinite at the critical point.

These thermodynamic accuracies are important for the selection of the driving machine, which must be coupled to the circuit of Figure 1, already described. In fluids with high compressibility, such as air, an interesting option is to pass through the device all the flow that circulates inside the tube 1. That leads to the assembly of Figure 2, on which a thermodynamically illustrative example, to show that the invented device makes sense. For this we rely on Figure 3, starting by giving the thermodynamically representative points, starting with the original flow upstream, which are the same conditions (very approximately 20) to those of 6T; indicated below, next to the others.

6T point, P = 1 MPa, T = 700 K

7T; 1 MPa 378.5 K

12T; 1 MPa 350 K

14T; 1.2 MPa 368.5 K 25

14aT 1.2 MPa 690 K

19T; 1.2 MPa 700 K

31T; 1.2 MPa 737 K

Since the specific heat at constant pressure is practically 1 kJ / kg · K, the enthalpy of the air (dry) is equal to the value of T, but expressed in kJ / kg

Hence it is seen that hot compression would have required 37 kJ / kg of dry air; and the performance would be low, 25% or so, which would make the Na power of that case be:

Na (kW) = (37 / 0.25) · m ’(kg / s) = 148m’

Where m ’is the mass air flow. 5

On the contrary, the one that is actually carried out starts with a temperature that is half the original of the air; and will have a much higher performance, of the order of 60%, so that the electric power consumed, Nb will be

Nb (kW) = (18.5 / 0.6) · m ’= 30.83m’

 10

Apart from being a lower power, the compressor will be much cheaper and more reliable. On the contrary, the invention requires a regenerative exchanger, with a power (thermal, non-electric) in kW, of 325m ’.

As for the characteristics of the three heat exchangers, they are 15 models and conventional features. The largest of the three is the regenerative one, with a thermal exchange power of 325m ’. It is a balanced exchanger, since the product m ’Cp is the same in the primary and secondary fluid, maintaining a temperature difference between the first and the second, of 10 ºC. twenty

The other two exchangers are smaller. The refrigerator has a power of 28.5m ’and the heater 10m’. In the latter there is the possibility of using smoke from a gas boiler for this purpose, and there would still be enthalpy in the fumes for other heating. The refrigerator is also simple, since in the previous example 25 the fluid must be cooled down to 77 ° C, which is easy to do with atmospheric air, even in summer.

Once the invention is clearly described, it is noted that the particular embodiments described above are subject to modifications in detail as long as they do not alter the fundamental principle and essence of the invention.

Claims (1)

1 - Fluid delivery device at very high temperature, applied to a main pipeline or conduction under pressure, characterized in that it consists of: - a fluid intake from inside the main pipe, said intake being made through the mouth of the device conduit in its first section, said conduit leaving the interior of the main pipe through a hermetic periphery hole, or fusing of the first stretch; - a fluid flow control valve captured from the main pipe, said valve being located in the first section of the device, said first section covering until it enters the regenerative exchanger, on the lower pressure side; - a regenerative heat exchanger, in which there is a low pressure conduit, in which the primary fluid, coming from the main pipe, cools, giving heat, through intermediate walls, to the fluid at higher pressure, and less temperature, which is heated, and comes from the drive mouth of the device driving machine; leaving the primary or lower pressure fluid from the regenerative exchanger, to go, through a second section of conduction to the auxiliary refrigerator; - said auxiliary refrigerator being an exchanger with a cold fluid current that comes from the outside of the device, and cools the fluid of the device to the temperature to which this auxiliary refrigerator is adjusted, from which the device fluid emerges at a temperature designated for the performance of the driving machine in which it enters from the exit of this auxiliary refrigerator; - this driving machine being a pump, a compressor, or a circulator in general, which gives the device fluid greater pressure, greater speed, or both; said fluid emerging from a conduit that enters as a secondary fluid in the regenerative heat exchanger, heating; - and its temperature is further increased after the previous step, by an auxiliary heating exchanger, whose heating fluid comes from a source of heat outside the device; - the fluid of the device is channeled through a last section conduit, which enters the main tube through an airtight flush, reaching the fluid discharge mouth of the device; in whose immediate vicinity downstream there is a venturi, or passage of reduced straight section with respect to the original of the main tube, after whose passage the straight section is reopened until the original section of the main tube is recovered. 2 - Fluid delivery device at a very high temperature, according to claim one, characterized in that, as a singular variant, the device is placed completely in series between the upstream and downstream parts of the main line, passing all the fluid from the main driving by the device. 3 - Fluid delivery device at a very high temperature, according to claim one, characterized in that the straight section of the output of the device (19) is reduced all the more the higher the speed through said output, which in turn leads to greater separation between said outlet (19) and the venturi (22).