WO2008015349A2

WO2008015349A2 - Method and device for feeding gas to an appartus

Info

Publication number: WO2008015349A2
Application number: PCT/FR2007/051544
Authority: WO
Inventors: Fabien Durand
Original assignee: L'air Liquide Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude
Priority date: 2006-07-31
Filing date: 2007-06-28
Publication date: 2008-02-07
Also published as: FR2904401A1; WO2008015349A3; FR2904401B1

Abstract

The invention concerns a method for feeding fluid in the gaseous state to an apparatus, comprising the following successive steps: a) admitting a fluid in the liquid state at an initial pressure into a downstream chamber (18); b) transferring the fluid in the liquid state contained in said downstream chamber (18), using a first end of a piston (3) to feed a regenerator (4) through an end of the latter maintained at a temperature lower than the evaporation point of the fluid; c) passing the fluid through the regenerator (4) and out a second end maintained at a temperature higher than the evaporation point of the fluid, so that the fluid leaves the regenerator (4) in the gaseous state, at a pressure higher than the initial pressure; d) feeding a second downstream chamber (22), maintained at a temperature higher than the evaporation point of the fluid, a part of said second downstream chamber (22) being delimited by a second end of the piston (3) of step c).

Description

METHOD AND DEVICE FOR GAS SUPPLYING AN INSTALLATION

The present invention relates to a method and a device for supplying gas, wherein a fluid in the liquid state supplies said device and is distributed in the gaseous state in the installation to be supplied.

This type of method and device are particularly suitable for supplying a gas installation from a liquid fluid stored at cryogenic temperatures, for example less than 150 degrees Kelvin, or even lower than 80 degrees Kelvin.

It is known to supply gas to facilities from a fluid in the liquid state at cryogenic temperature using a two-step process, using two independent devices.

At first, the fluid in the liquid state is pumped by a liquid volumetric pump, in particular from a reservoir. For this step, a cryogenic pump is used which allows the fluid to be transferred to the liquid state.

One can for example use a piston pump, which can provide very high pressures, such as in particular marketed by CRYOMEC or CRYOSTAR companies.

In a second step, the fluid in the liquid state is vaporized in a heater to produce the gas to be introduced into the plant to be fed.

Such heaters are in particular marketed by the company CRYOLOR under the commercial reference VAP CRYOLOR and allow to obtain gas flow rates suitable for many facilities to supply.

This mode of gas distribution, although very commonly used, has the following disadvantages:

it leads to a large consumption of mechanical energy to effect the compression of the fluid in the liquid state; - leaks in the volumetric compressor are frequently observed due to the fact that the pressure differences are very high;

dynamic seals are used to operate such installations, these seals require close monitoring and frequent maintenance and their service life is limited, imposing unwanted shutdowns of the installations; the large pressure differences in these installations lead to high stresses in the parts that compose them and therefore require a specific design of the parts and a choice of specific materials that lead to additional costs of these installations;

- It is difficult to obtain large flow variations with such facilities, because it is observed that leakage becomes predominant for low flow rates.

The object of the present invention is to overcome the above disadvantages.

Therefore, the object of the invention is to provide a method where the consumption of mechanical energy is greatly reduced compared with known methods for supplying gaseous fluid to an installation, from a fluid in the state liquid.

This object is achieved by a method for supplying gaseous fluid to an installation comprising the following successive steps: a) admission of a fluid in the liquid state to an initial pressure in a downstream chamber; b) transfer of the fluid to the liquid state contained in said downstream chamber with a first end of a piston so as to feed a regenerator by an end thereof maintained at a temperature below the evaporation point of the fluid; c) passage of the fluid in the regenerator and output by a second end maintained at a temperature above the point of evaporation of the fluid, so that the fluid exits the regenerator in the gaseous state, at a pressure greater than the pressure initial ; d) supplying a second downstream chamber maintained at a temperature higher than the point of evaporation of the fluid, a part of said second downstream chamber being delimited by a second end of the piston of step c).

Such a method implements a "thermal compressor" and no longer a mechanical compressor. This results in very low power consumption (especially electricity).

The term "regenerator" means a component capable of storing heat and returning it when it is traversed by a fluid. According to one embodiment, step a) comprises the following steps: a1) admission of a fluid in the liquid state by suction in a chamber; a2) compressing the fluid in the liquid state contained in said chamber and transferring the fluid into the downstream chamber.

Step a1) can be performed during step b). According to one embodiment, the method further comprises the following step, subsequent to step d): e) increasing the pressure of the fluid in the gaseous state to a threshold value corresponding to the supply pressure the plant to supply and release the fluid in the gaseous state in said installation. Typically, an initial pressure value of the fluid in the liquid state can be between 10 mbar and 15 bara, for example around 1 bara, and the gas supply pressure of a gas system can be respectively between 1 and 500 bara, for example around 150 bara.

According to one embodiment, the method further comprises the following steps subsequent to step e) when the pressure of the fluid in the gaseous state in the second downstream chamber is lower than that of the feed threshold: f) actuation of the piston so as to evacuate the fluid in the gaseous state of the second downstream chamber; g) passage of the fluid in the regenerator to supply the first downstream chamber; h) repeating steps a) to h) to constitute a gaseous fluid supply cycle of an installation.

It is thus possible to obtain a cycle of continuous supply of fluid in the gaseous state. The implementation of such a method does not require the use of high pressure dynamic seals. As a result, the service life of the installations to implement it is much greater than that of known installations, in particular using a cryogenic pump and then a heater.

Step a1) can be performed during step f) or step g).

According to one embodiment of the method, the fluid in the liquid state is at a cryogenic temperature. The fluid is then in particular chosen from the list comprising He, H ₂ , Ne, CO, Ar, N ₂ , O ₂ , CH ₄ , CO ₂ , NO, Kr, Xe or their mixture.

According to one embodiment of the present method, the second end of the regenerator and the second downstream chamber are maintained substantially at room temperature.

However, it should be noted that the invention is not limited to the fluid distribution whose liquid state corresponds to cryogenic temperatures, but that it would also be possible, for example, also to use such a method for dispensing steam. water under pressure from room temperature water and a heat source.

The invention also relates to a gaseous fluid supply device for an installation adapted to implement the method according to the invention which comprises:

a "cold" part comprising a cavity for sealingly receiving an end of a piston, so as to constitute a downstream chamber,

a "hot" part, comprising a cavity for sealingly receiving a second end of said piston, in order to constitute a second downstream chamber,

said piston provided with actuating means for moving in the cavity of the "cold" part and in the cavity of the "hot" part,

a regenerator in communication with the cavity of the "cold" part and the cavity of the "hot" part,

means for supplying the cavity of the "cold" part with fluid in the liquid state,

- Release means at a predetermined pressure of a fluid in the gaseous state in communication with the cavity of the "hot" part.

Said device is implemented with a very low energy consumption.

Outward leakage is very low. The device is likely to operate normally for a flow rate ranging from 0 to 100% of the flow rate nominal.

The displacement piston in the cavities of the parts

"cold" and "hot" can be operated with a weak force. It is possible to operate it with a conventional motor, but also to operate it with electromagnets or even with a superconducting device.

It is further noted that the parts needed to implement said device are of very simple design, thus leading to particularly advantageous manufacturing costs.

In the context of the invention, the term "part"

"cold" the part of the device which receives the fluid in the liquid state, and whose temperature is, when the installation is in operation, slightly less than the evaporation temperature of the fluid with which the compressor is supplied. The term "hot" part, the part of the device that receives the fluid in the gaseous state, after passing through the regenerator, and whose temperature is, when the installation operates, greater than the evaporation temperature of the fluid with which one wishes to supply an installation.

According to one embodiment of the device according to the invention, the components are chosen so that in operation, the "cold" part is at cryogenic temperature and the "hot" part is at room temperature.

According to one embodiment of said device, the fluid supply means in the liquid state of the cavity of the "cold" part comprise a chamber, in communication with a pipe with the outside of the device and capable of being connected to a fluid supply system in the liquid state, a system nonreturn located in said pipe between said chamber and the outside of the device, a piston provided with actuating means for moving in said chamber, a communication means comprising a non-return system between said chamber and the cavity of the "cold" part.

It is possible to use for this piston, a piston bellows or membrane. Such pistons can further limit the leakage of the device, or even to make them non-existent. According to one embodiment of said device, the means for releasing a fluid in the gaseous state in communication with the cavity of the "hot" part comprise a pipe connecting said cavity to the outside of the device, and an anti-condensation system. return allowing the fluid to escape when the pressure is greater than the pressure downstream of the device.

For example the anti-return system is a check valve.

According to one embodiment, the "cold" part is made of stainless steel and is isolated by a multilayer insulation comprising, for example, a gap between layers.

Such an insulation system can use insulators commonly called "vacuum super insulation".

According to one embodiment, the "hot" part is made of copper.

According to one embodiment, the "hot" part is surrounded by a system for circulating fluid, in particular air or water, making it possible to maintain it at a substantially constant temperature. According to one embodiment, the regenerator consists of a tube, in particular cylindrical, filled with a material capable of storing and returning the heat and allowing the fluid to pass to the liquid state and gaseous

The material capable of storing and returning heat may, for example, be in the form of stacked balls, stacked grids, or any other form that makes it possible to obtain large surfaces that allow heat exchange without thermally shorting the surface. hot part of the cold part. Said material may for example be made of stainless steel. According to one embodiment, the piston received by the cavities of the "hot" and "cold" parts is made of stainless steel.

The invention will be detailed hereinafter with the aid of non-limiting examples illustrated by the following figures:

- Figure 1: schematic sectional view of a device according to the invention,

- Figure 2 (a to d): schematic view of said device implemented according to different steps of the method according to the invention.

FIG. 1 shows a schematic sectional view of a device according to the invention. It comprises a cold part 1 of stainless steel, a hot part 2 of copper, connected by a regenerator 4. Each of the cold parts 1 and 2 hot comprise a cavity respectively 18 and 22 of cylindrical shape and hemispherical end. A piston 3 of cylindrical shape and hemispherical end, made of stainless steel, can move inside these cavities 18 and 22. This piston 3 can occupy the entire space of the cavity 22 or 18 and thus release a free space called respectively first and second downstream chamber.

The device can be connected to a fluid reservoir in the liquid state by a valve 11. A pipe 13, comprising a nonreturn valve 12, supplies a chamber 14 in which a piston 15 can be actuated by a motor or other suitable device. The chamber 14 is connected to the first downstream chamber by a pipe 16 comprising a non-return valve 17. The first downstream chamber is connected to a first end of the regenerator 4 via a pipe 19. The regenerator 4 is a stainless steel tube filled of stainless steel balls.

A pipe 21 connects the opposite end of the regenerator 4 to the second downstream chamber. The second downstream chamber may be placed in communication with the outside, in particular an installation to be powered, by a pipe 23 provided with a non-return valve 24. FIG. 2 represents the position of the various members of the device of FIG. four stages of operation of this device. FIG. 2a shows the phase of suction of the fluid in the liquid state, in particular from a reservoir, by displacement of the piston 15 along the arrow represented, to increase the volume of the chamber 14.

When the volume of the desired liquid is introduced into the chamber 14, the piston 15 is actuated, as represented by the arrow in FIG. 2b, in the direction opposite to that shown in FIG. 2a, and the fluid in the liquid state is introduced to the initial pressure in the first downstream chamber 18. The non-return valve 12 is oriented so that the fluid in the liquid state can not return to the reservoir.

After complete introduction of the fluid in the liquid state into the first downstream chamber 18, the piston 3 is moved in order to reflux the fluid in the liquid state in the pipe 19 to the regenerator 4, as shown in Figure 2c.

The nonreturn valve 17 is oriented so as to avoid any reflux towards the chamber 14.

During the passage in the regenerator 4, the fluid heats up and goes from the liquid state to the gaseous state, because the end of the regenerator 4 in connection with the pipe 19 is kept at a temperature below the temperature of evaporation of the fluid while the end of the regenerator 4 in connection with the pipe 21 is maintained at a temperature above the evaporation temperature of the fluid.

When the piston 3 reaches the end of its stroke in the first downstream chamber, most of the fluid is in the gaseous state in the second downstream chamber at a high pressure.

When, during the displacement of the piston 3 in the first downstream chamber, the gas pressure in the second downstream chamber reaches a pressure greater than the pressure in the outlet 25, the gas is released from the device by the valve 24 and the outlet 25.

FIG. 2d shows the subsequent step where, when the pressure of the fluid in the gaseous state is insufficient to escape from the device via the nonreturn valve 24, the piston 3 is moved into the second downstream chamber until recover its position shown in Figure 2a.

During this step, the gas remaining in the second downstream chamber reflux through the pipe 21 in the regenerator 4 and a portion of the fluid is converted from the gaseous state to the liquid state and fed through the pipe 19 the first downstream chamber This transformation is accompanied by a pressure drop in the first downstream chamber.

A new cycle can then be performed as previously described.

The invention is not limited to these types of embodiments and must be interpreted in a non-limiting manner, and encompassing any equivalent embodiment.

Claims

1. A method for supplying gaseous fluid to an installation comprising the following successive steps: a) admission of a fluid in the liquid state to an initial pressure in a downstream chamber (18); b) transferring the fluid in the liquid state contained in said downstream chamber (18) by means of a first end of a piston (3) so as to feed a regenerator (4) with one end thereof kept at a temperature below the point of evaporation of the fluid; c) passage of the fluid in the regenerator (4) and output by a second end maintained at a temperature above the point of evaporation of the fluid, so that the fluid exits the regenerator (4) in the gaseous state, a pressure higher than the initial pressure; d) supplying a second downstream chamber (22) maintained at a temperature higher than the point of evaporation of the fluid, a portion of said second downstream chamber (22) being delimited by a second end of the piston (3) of the step vs) .

2. Method according to the preceding claim wherein step a) comprises the following steps: al) admission of a fluid in the liquid state by suction in a chamber (14); a2) compressing the fluid in the liquid state contained in said chamber (14) and transferring the fluid into the downstream chamber (18).

3. Method according to the preceding claim wherein step a1) is carried out during step b).

4. A method according to any one of the preceding claims which further comprises the following step, subsequent to step d): e) increasing the pressure of the fluid in the gaseous state to a threshold value corresponding to the supply pressure of the installation to supply and release of the fluid in the gaseous state in said installation.

5. Method according to the preceding claim further comprising the following steps subsequent to step e) when the pressure of the fluid in the gaseous state in the second downstream chamber (22) is lower than that of the feed threshold: actuating the piston (3) so as to discharge the gaseous fluid from the second downstream chamber (22); g) passage of the fluid in the regenerator (4) to supply the first downstream chamber (18); h) repeating steps a) to h) to constitute a gaseous fluid supply cycle of an installation.

6. Method according to the preceding claim wherein step a1) is carried out during step f) or step g).

The method of any of the preceding claims wherein the fluid in the liquid state is at a cryogenic temperature.

8. The method of claim 7 wherein the fluid is selected from the list comprising He, H2, Ne, CO, Ar, N2, O2, _CH4, CO2, NO, Kr, Xe or a mixture thereof.

9. Method according to any one of the preceding claims characterized in that the second end of the regenerator (4) and the second downstream chamber (22) are maintained substantially at room temperature.

10. Fluid supply device in the state gaseous of an installation characterized in that it comprises:

a "cold" part (1) comprising a cavity (18) for sealingly receiving one end of a piston (3), in order to constitute a downstream chamber (18), a "hot" part (2), comprising a cavity (22) for sealingly receiving a second end of said piston (3) to form a second downstream chamber (22), - said piston (3) having actuating means for moving in the cavity (18). ) of the "cold" part and in the cavity of the "hot" part (22), a regenerator (4) in communication with the cavity (18) of the "cold" part and the cavity of the "hot" part ( 22)

feed means (14) for the cavity (18) of the "cold" part in fluid in the liquid state, means for releasing (24) at a determined pressure of a fluid in the gaseous state, communication with the cavity (22) of the "hot" part.

11. Device according to claim 10, characterized in that the two upper and lower ends of the regenerator are maintained at respectively higher and lower temperatures to the evaporation temperature of the fluid via pipes 19, 21 respectively.

12. Device according to claim 10 or 11 characterized in that the fluid supply means in the liquid state of the cavity of the "cold" part (18) comprise a chamber (14), in communication via a pipe ( 13) with the outside of the device and capable of being connected to a fluid supply system (11) in the liquid state, an anti-return system (12) located in said duct (13) between said chamber (14) and the outside of the device, a piston (15) provided with actuating means for moving in said chamber (14), a communication means comprising an anti-rotation system, return between said chamber and the cavity (18) of the "cold" part (1).

13. Device according to any one of claims 10 to 12, characterized in that the means for releasing a fluid in the gaseous state in communication with the cavity (22) of the "hot" part comprise a pipe (23). ) connecting this cavity (22) and the outside of the device, and a non-return system (24) allowing the fluid to escape preferably only when the pressure is greater than the downstream pressure.

14. Device according to claim 13 characterized in that the channel (23) of release is distinct and independent of conduits (19, 21) for placing the regenerator (4) in communication with the cavity of the cold part (18) and with the cavity of the hot part (22).

15. Device according to any one of claims 12 to 14 characterized in that said non-return system (12, 17, 24) is a non-return valve.

16. Device according to any one of claims 10 to 15 characterized in that the part

"Cold" (1) is made of stainless steel and is insulated by a multilayer insulation comprising for example vacuum between layers.

17. Device according to any one of claims 10 to 16 characterized in that the part

"Hot" (2) is copper.

18. Device according to any one of claims 10 to 17 characterized in that the part "Hot" (2) is surrounded by a fluid circulation system, in particular air or water, to maintain it at substantially constant temperature.

19. Device according to any one of claims 10 to 18 characterized in that the regenerator (4) consists of a tube, in particular cylindrical, filled with a material capable of storing and returning the heat and pass the fluid in the liquid and gaseous state.

20. Device according to claim 19 characterized in that said material is a stack of stainless steel balls.

21. Device according to any one of claims 10 to 20 characterized in that the piston received by the cavities of the "hot" and "cold" parts is made of stainless steel.