KR20180105204A - Apparatus and method for compressing fluid - Google Patents

Abstract

The apparatus for compressing the first fluid 14 comprises a cylinder tube 6 and a piston assembly 7 slidably mounted therein. The piston assembly (7) includes a first member (10) and a second piston member (8) defining a space therebetween. This space is configured to receive a second fluid 16 that is used to compress the first fluid 14. The apparatus further comprises a pump (48) and a second fluid supply conduit (50, 38) for supplying a second fluid to the space between the first and second piston members, and the second piston member (8) And a valve (24) configured to control the flow of the second fluid through the fluid supply conduits (50, 38) into the space between the piston members.

Description

Apparatus and method for compressing fluid

The present invention relates to an apparatus for compressing a fluid. In particular, the present invention relates to compressors, and more particularly, but not exclusively, to vibration compressors, particularly hydraulically driven compressors. The present invention relates to a piston compressor or ion compressor, and a single-stage or multi-stage compressor. The present invention relates primarily to seals, in particular axial seals, in such compressors which can be carried out as stem seals or piston seals. The present invention further extends to methods of compressing fluids, especially gases.

A gas seal in a compressor in which a leakage relief is fitted receives the total gas pressure during the compression process (equivalent to the actual gas pressure), which inevitably leads to wear during continued use. In addition, as the back pressure for the seal increases within the compressor, the wear of the seal also increases as a result of the increased pre-stress. Experience has shown that the service life of these stressed gas seals is in the range of 2500-3000 km, considering the proper dimensions.

Therefore, there is a need to provide an improved compressor design that increases the service life of the seal. The present invention arises from the inventor's efforts to overcome the problems associated with the prior art.

According to a first aspect of the present invention there is provided an apparatus for compressing a first fluid, the apparatus comprising a piston cylinder and a compressor piston including a piston assembly slidably mounted within the piston cylinder, A first and a second spaced piston member defining a space defined between said first and second piston members for receiving a second fluid used to compress fluid; Means.

In prior art compressors, the fluid seal in contact with the pressurized fluid is exposed to a pressure equivalent to the actual gas-pressure, resulting in considerable wear to the seal. However, by contrast, in the apparatus of the present invention, by contrast, the piston assembly includes two spaced apart piston members, whereby the fluid seal of the compressor is exposed to a reduced pressure of only 2 bar. Thus, the device significantly reduces the load on the fluid seal, thereby reducing wear and tear. Advantageously, therefore, the device prolongs the wear time for the piston seal due to the excellent lubrication produced between the piston assembly and the cylinder tube. This provides mechanical protection against improved corrosion protection and compressor knocking and low noise emissions. An additional benefit is increased plant availability, including longer maintenance life, leading to lower maintenance costs.

Preferably, the apparatus includes a storage tank configured to store a second fluid therein. Preferably, the means for supplying the second fluid to the space between the first and second piston members comprises at least one member extending between the pump and, preferably, the space between the storage tank and the piston member to which the fluid is supplied, 2 fluid supply conduit.

Preferably, the first piston member (referred to herein as a " floating piston ") is configured to vibrate within the cylinder tube, and is preferably sealed together with the cylinder tube by a first radial seal. The first radial seal may be a stem seal or a piston seal. Preferably, the first piston member is mounted substantially centrally on the second piston member, thereby being guided concentrically. Preferably, the second piston member (referred to herein as the " main piston ") is configured to vibrate in the cylinder tube and is preferably sealed together with the cylinder tube by a second radial seal. The second radial seal may be a stem seal or a piston seal.

Preferably, the first fluid to be compressed is in contact with one side of the first piston member and the second fluid is in contact with the opposite side of the first piston member. Preferably, the second fluid acts as a lubricating fluid when disposed between the first and second piston members of the piston assembly, when acting to reduce friction between the first radial seal and the cylinder tube. Preferably, the second fluid acts as a drive fluid when disposed below the piston assembly, when the piston assembly vibrates in the cylinder tube and thereby serves to compress the first fluid.

Preferably, the second fluid disposed in the space between the first and second piston members is fluidly connected to the storage tank, preferably through at least one second fluid leakage conduit. Thus, any second fluid leaking through the second seal is supplied to the storage tank. Advantageously, therefore, the device is arranged such that, during use of the compressor piston, any leakage of the second fluid in the second seal is automatically balanced by the supplemental flow of the second fluid, Lt; RTI ID = 0.0 > leakage < / RTI > return line.

Preferably, the second piston member includes a valve configured to control the flow of the second fluid into the space between the piston members through the at least one second fluid supply conduit. Preferably, the valve includes biasing means configured to deflect the valve in a closed configuration in the second fluid supply conduit. The biasing means preferably comprises a spring, more preferably a helical spring or cup spring.

Preferably, the second piston member comprises actuating means configured to actuate the valve in response to a change in pressure for the first seal, or in response to the position of the first piston member relative to the actuation set point. Preferably, the actuation means is configured to activate the pump in response to a pressure change for the first seal, or in response to the position of the first piston member relative to the actuation set point. Preferably, the actuation means is configured to open the valve when the pressure for the first seal increases, and preferably activates the pump to pump the second fluid through the valve. Conversely, preferably, the actuation means is configured to close the valve when the pressure for the first seal decreases, preferably deactivating the pump to prevent pumping of the second fluid.

Thus, by way of example, when the pressure on the first fluid side of the first seal increases due to leakage of the second fluid through the second seal, the first piston member is preferably urged toward the second piston member, Whereby the actuating means is configured to open the valve.

In another preferred embodiment, the actuating means is configured to open the valve when the position of the first piston member reaches the operating set point, and / or the actuating means moves the position of the first piston member past the operating set point The valve is closed. It will be appreciated that the valve and pump may be activated by the actuation means when the position of the floating piston drops below the operating setpoint that may occur due to fluid loss or entrapped compressible gas. This may not necessarily result in a decrease or increase in pressure for the first seal.

Preferably, the pump is configured to pump the second fluid into the space between the first and second piston members along the at least one conduit through the open valve activated by the actuation means from the storage tank. Preferably, the second piston member includes at least one conduit extending radially outwardly from the valve into the space between the piston members. Preferably, the at least one conduit extends diagonally from the valve into the space between the piston members.

Advantageously, a substantially constant depth of the second fluid is maintained between the first and second piston members. The second fluid may be pumped into the space between the piston members at any stage of the compression process. Preferably, however, the pump is activated during the non-compression phase, i. E. When the piston assembly is located at the bottom of the cylinder tube or adjacent the bottom of the cylinder tube.

Preferably, the device is configured such that the pressure between the first fluid side of the first piston member and the second fluid is substantially balanced. Advantageously, the pre-stress tension of the deflection means applied to the actuating means substantially corresponds to the weight of the first piston member and the frictional force created between the cylinder tube and the first seal.

Preferably, the pressure differential between the side of the first piston member in contact with the first fluid and the side in contact with the second fluid is less than 75 Bar, more preferably less than 50 Bar, even more preferably less than 25 Bar, and even more More preferably less than 15 Bar. More preferably, the pressure difference between the side of the first piston member in contact with the first fluid and the side in contact with the second fluid is less than 10 Bar, preferably less than 5 Bar, and most preferably less than 3 Bar.

As a result, a small radial force between the first piston member and the first radial seal results in less wear and damage. Advantageously, the device is configured to receive only the pre-tension pressure defined by the seal to minimize wear on the seal.

Preferably, the compressor piston includes an inlet through which the uncompressed first fluid is fed into and an outlet through which the compressed first fluid exits. Preferably, the pressure of the inlet fluid is about 1-200 barg, more preferably about 1-30 barg, and most preferably about 3-10 barg.

Preferably, the compressor piston is configured to increase the pressure of the first fluid from 100 bara to 1500 bara. More preferably, the compressor piston is configured to increase the pressure of the first fluid from 150 bara to 1250 bara. Most preferably, the compressor piston is configured to increase the pressure of the first fluid from 300 bara to 1000 bara. Preferably, the pressure of the outlet fluid is about 350 Bar.

It may be appreciated that the desired pressure of the first fluid is dependent on the first fluid used. Thus, when the first fluid is hydrogen, the compressor piston is configured to increase the pressure of the first fluid from 500 bara to 1500 bara, more preferably from 700 bara to 1400 bara, and most preferably from 800 bara to 1300 bara .

Alternatively, when the first fluid is a natural gas, the compressor piston is configured to increase the pressure of the gas to 100 bara to 700 bara, more preferably 200 bara to 600 bara, and most preferably 300 bara to 500 bara .

The first fluid may comprise a liquid. Preferably, however, the first fluid comprises gases such as natural gas, fuel gas, hydrogen, gaseous hydrocarbons, liquefied combustion gases, inert gases such as nitrogen, helium, oxygen, and argon, or mixtures thereof. More preferably, the first fluid comprises a fuel gas, such as natural gas or hydrogen.

The second fluid may preferably comprise a liquid that is substantially incompressible. Preferably, the second fluid comprises an ionic liquid, LOHC (Liquid Organic Hydrogen Storage), semi-heavy water (HDO), oxidized deuterium (heavy water), water or hydraulic oil, or mixtures thereof. Most preferably, the second fluid comprises LOHC or an ionic liquid. An ionic liquid is a class of substances which are substantially solely composed of ions and which are liquid at temperatures below 100 ° C. LOHC is a carbon-based liquid with very similar properties to ionic liquids. The advantages of ionic liquids and LOHCs are that they have low or no vapor pressure, good lubricity, essentially gas dissolution, high thermal stability and high heat capacity.

In one embodiment, preferably an embodiment in which the second fluid is an ionic liquid, the apparatus is configured to use an ionic liquid cushion disposed between the piston assembly and the first fluid to be compressed. Preferably, the ionic liquid cushion is disposed on top of the first piston member (i. E., The floating piston member) in the compression phase and fills all dead spaces. The ionic liquid cushion preferably comprises a fluid having a low vapor pressure and may comprise or consist of a substantially pure ionic liquid, or a mixture of ionic liquid and LOHC.

Preferably, the apparatus comprises a vibratory compressor. Preferably, the apparatus comprises a hydraulically driven compressor. In a preferred embodiment, the apparatus comprises a piston compressor. Preferably, the apparatus comprises a liquid piston compressor in which a second fluid (preferably a liquid) is used to drive compression of the first fluid (preferably gas). In another preferred embodiment, the apparatus comprises an ion compressor.

In one embodiment, the apparatus includes a compressor. Preferably, the apparatus comprises at least one displacement piston configured to vibrate in the housing and configured to displace the second fluid to and from the compressor piston to compress the first fluid therein, Lt; RTI ID = 0.0 > functionally < / RTI > The displacement pistons may be connected in series. The vibration of the displacement piston or each displacement piston driven by the plunger is facilitated by the lubricant supplied through the at least one inlet into the housing. In some embodiments, the lubricant for the plunger may be hydraulic oil, LOHC or an ionic liquid, or a mixture thereof.

In another embodiment, the apparatus preferably includes a multi-stage compressor (e.g., two, three or four stages) comprising a plurality of compressor stages connected in series. Preferably, the apparatus comprises 1 to 20 compressor stages. More preferably, the apparatus comprises two to ten compressor stages. Most preferably, the apparatus comprises three to five compressor stages. In a most preferred embodiment, the apparatus comprises four compressor stages connected in series.

The apparatus may comprise a multi-stage compressor comprising a plurality of compressor stages connected in parallel. Advantageously, this increases the throughput of the compressor.

Thus, in one embodiment, the apparatus may comprise a plurality of series, each series comprising a plurality of compressor stages connected in series, the plurality of series being connected in parallel.

According to a second aspect of the present invention, there is provided a method of compressing a first fluid,

Supplying a first fluid to a compressor piston comprising a piston cylinder and a piston assembly slidably mounted therein, the piston assembly having a space configured to receive a second fluid used to compress the first fluid Said first and second spaced piston members defining between said first and second spaced piston members,

- supplying a second fluid to the space between the first and second piston members and compressing the first fluid

.

Preferably, the method of the second aspect includes use of the apparatus of the first aspect.

Preferably, the method preferably further comprises the step of applying a second fluid to the space between the first and second piston members along at least one second fluid supply conduit extending between the space between the piston members and the second fluid storage tank Lt; / RTI >

Preferably, the method includes supplying any of the second fluid leaking through the second radial seal disposed between the second piston member and the cylinder tube to the storage tank.

Preferably, the method includes controlling the flow of the second fluid through the at least one second fluid supply conduit into a space between the piston members through a valve disposed in the at least one second fluid supply conduit . Preferably, the method includes deflecting the valve in a closed configuration in a second fluid supply conduit. The biasing means preferably comprises a spring, more preferably a helical spring.

Preferably, the method includes activating the valve in response to a change in pressure for the first radial seal, or in response to the position of the first piston member relative to the set operating point. Advantageously, the method comprises activating the pump in response to a pressure change for the first radial seal, or in response to the position of the first piston member relative to the actuation set point. Preferably, the method includes opening the valve and preferably pumping the second fluid through the valve as the pressure for the first radial seal increases. Preferably, the method includes closing the valve when the pressure for the first radial seal decreases, and preferably deactivating the pump to prevent pumping of the second fluid.

In use, when the pressure on the first fluid side of the first radial seal increases due to leakage of the second fluid through the second radial seal, the method further comprises directing the first piston member toward the second piston member Thereby opening the valve.

The method may include opening the valve when the position of the first piston member reaches the operating set point, and / or closing the valve when the position of the first piston member moves past the operating set point.

Preferably, the method comprises pumping the second fluid from the storage tank through the open valve and into the space between the first and second piston members along the at least one conduit. Preferably, the method includes pumping a second fluid extending along the at least one conduit extending radially outwardly from the valve into the space between the piston members.

Preferably, the method includes maintaining a substantially constant depth of the second fluid between the first and second piston members. The method may include pumping the second fluid into the space between the piston members at any stage of the compression process. Preferably, however, the method includes activating the pump during the non-compression phase, i.e. when the piston assembly is disposed adjacent the bottom of the cylinder tube or the bottom of the cylinder tube.

Preferably, the method includes balancing the pressure between the first fluid side and the second fluid of the first piston member. Preferably, the pressure difference between the side of the first piston member in contact with the first fluid and the side in contact with the second fluid is less than 75 Bar, more preferably less than 50 Bar, even more preferably less than 25 Bar, and Even more preferably less than 15 Bar. More preferably, the pressure difference between the side of the first piston member in contact with the first fluid and the side in contact with the second fluid is less than 10 Bar, preferably less than 5 Bar, most preferably less than 3 Bar.

Preferably, the method includes feeding the uncompressed first fluid through the inlet into the compressor piston, and supplying the compressed fluid through the outlet. Preferably, the method includes the use of a liquid piston compressor in which a second fluid (preferably a liquid) is used to drive the compression of the first fluid (preferably a gas) . In another preferred embodiment, the apparatus comprises an ion compressor.

Preferably, the method includes moving a second fluid from the compressor piston to the compressor piston and compressing the first fluid therein by one or more displacement pistons configured to vibrate in the housing.

The first fluid may comprise a liquid. Preferably, the first fluid comprises gases such as natural gas, fuel gas, hydrogen, gaseous hydrocarbons, liquefied combustion gases, inert gases such as nitrogen, helium, oxygen, and argon, or mixtures thereof.

The second fluid may preferably comprise a liquid that is substantially incompressible. Preferably, the second fluid comprises an ionic liquid, LOHC (Liquid Organic Hydrogen Storage), semi-heavy water (HDO), deuterated hydrogen deuterium (heavy water), water or hydraulic oil, or mixtures thereof. Most preferably, the second fluid comprises LOHC or an ionic liquid.

In one embodiment and preferably in embodiments where the second fluid is an ionic liquid, the method includes the use of an ionic liquid cushion disposed between the piston and the first fluid to be compressed. Preferably, the ionic liquid cushion is disposed on top of the first piston member and fills all of the dead space in the compression phase. The ionic liquid cushion preferably comprises a fluid having a low vapor pressure and may comprise or consist of a substantially pure ionic liquid or a mixture of ionic liquid and LOHC.

It is to be understood that all features described herein (including any appended claims, abstract and drawings), and / or any steps or steps of any disclosed method or process described herein, May be combined with any of the above aspects of any combination, except for combinations.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings.

1 is a schematic view of a first embodiment of a gas compressor according to the invention with two spaced apart piston compressors (left and right) each having a piston assembly slidably mounted in a cylinder tube;
2 is a schematic diagram of a second embodiment of a gas compressor according to the invention with two spaced apart piston compressors (left and right) each having a slidably mounted piston assembly, wherein the piston assembly of each compressor has Using the ionic liquid cushion, the piston assembly of the piston compressor of the left side is moved to the top of the cylinder tube, thereby compressing the gas inside through the ion cushion, and the piston assembly of the piston compressor of the right side, And is positioned toward the middle of the cylinder tube so as to be maintained in an unstable state,
Fig. 3 is a side cross-sectional view of the compressor shown in Fig. 1, in which the piston assembly of the piston compressor of the left side is moved to the top of the cylinder tube, thereby compressing the gas therein, and the piston assembly of the piston compressor of the right side, Is placed at the base of the cylinder tube so that fresh gas is drawn towards the bottom dead center,
Figure 4 is an enlarged side cross-sectional view of the top portion of the left piston compressor shown in Figure 3, with the piston assembly located at the top of the cylinder tube having compressed gas,
5 is an enlarged side cross-sectional view of one piston assembly of a piston compressor present in a compressor of the present invention.

example

Referring to Figures 1 to 3, there is shown an apparatus for compressing a gas 14 such as natural gas (CNG), fuel gas, hydrogen, gaseous hydrocarbons, liquefied combustion gases, inert gases such as nitrogen, helium, oxygen, An embodiment of the compressor 2 is shown. For example, the compressor 2 may be used to compress hydrogen used as fuel in a hydrogen-powered vehicle. The compression is hydraulically driven, for example, by an ion compressor or a piston compressor, as shown in the figure. Therefore, it will be appreciated that the compressor 2 is a liquid piston compressor.

1 and 2 show the first and second embodiments of the compressor 2, respectively. In each embodiment, the compressor 2 comprises two parallel spaced apart piston compressors 4, in which uncompressed gas 14 is fed into the piston compressor 4 through an inlet 40, (14) is discharged from the piston compressor (4) through the outlet (41). The pressure of the inlet gas 14 is about 6 Bar and the pressure of the compressed gas 14 at the outlet is about 350 Bar. The inlet 40 and the outlet 41 are provided with a very low operating frequency of 0.1 Hz-5 Hz, more preferably 0.5 Hz -1.5 Hz for the valve 14, Channel valve 44 is fitted.

As can be seen in the figure, the illustrated compressor 2 is once a compressor (i.e., a 1-stage). The piston compressor 4 of the illustrated one-stage system is in parallel and is driven by a single plunger 30 which includes a piston 32 connected to a single plunger 30 within a housing 58, Thereby causing a reciprocating vibration of the motor. Each piston 32 is arranged to displace the hydraulic drive fluid 16 disposed in the reservoir 60 from the compressor piston 4 and from the compressor piston 4, (Not shown).

However, at least two of the compressors 2 of FIG. 3 are connected in series so that the discharge through the outlet 41 of two identical pressure stage compressors 4 is connected to the suction inlet port 40 of the high- Is also considered. For example, there may be four compressor (2) stages where the pressure of the inlet gas 14 into the first compressor 2 is 6 bara and the pressure of the compressed gas 14 at the outlet is 16.6 bara , The pressure of the inlet gas 14 into the second compressor 2 is 16.6 bara and the pressure of the outlet gas 14 is 45.7 bara and the pressure of the inlet gas 14 into the third compressor 2 is 45.7 bara bara, the pressure of the outlet gas 14 is 126 bara, the pressure of the inlet gas 14 into the fourth compressor 2 is 126 bara and the pressure of the outlet gas 14 is 350 bara.

The hydraulic drive fluid 16 is incompressible and may be any ionic liquid, LOHC (liquid organic hydrogen storage), heavy water, deuterated hydrogen, water, or hydraulic oil, or a mixture thereof. The entire hydraulic system needs to be designed for low lubricity of heavy water as compared to standard lubricants such as, for example, oil. The vibration of the piston 32 driven by the plunger 30 is facilitated by the lubricant 34 which is fed into the housing 58 through the inlet 54. In some embodiments, the lubricant 34 for the plunger 30 may be hydraulic oil 34, LOHC or an ionic liquid, or a mixture thereof. The lubricant 34 must be kept separate from the drive fluid 16 since it needs to have a different compression ratio.

In Figures 2 and 3 there is shown a left piston compressor 4 in a configuration for compressing gas 14 and a piston 14 for compressing the gas 14 after the fresh gas is sucked through the suction valve 40, There is shown a compressor 2 having a piston compressor 4 on the right side of the configuration that is maintained in a state of being maintained. A position sensor 46 connected to each pump 42 detects the configuration of each piston compressor 4 and facilitates its own oscillation within it so that gas 14 is supplied to the piston compressor 4), and then discharged at a high pressure through the outlet 41. [0064]

In prior art compressors, the gas seal places the gas 14 to be compressed, and the piston is subjected to total gas pressure which causes wear during continued use. 3 and 4, the compressor 2 of the present invention is provided with a mechanism (not shown) for substantially extending the life of the gas seal 18 in the piston compressor 4 by reducing wear and tear, the mechanism is fitted. 5, each piston compressor 4 includes a cylinder tube 6 in which a piston assembly 7 (also known as a " dummy " piston) is slidably mounted do. Each piston assembly 7 consists of a floating piston 10 connected to the main piston 8 spaced apart. The floating piston 10 is arranged to vibrate in the cylinder tube 6 and is sealed internally by a radial gas seal 18, such as a V-piston ring. One side of the floating piston 10 (i.e., the top side shown in Figures 1, 2 and 5) is in contact with the gas 14 to be compressed (e.g., hydrogen or compressed natural gas, CNG) have. On the other side (i.e., the lower side shown in Figs. 1, 2 and 5), the floating piston 10 is in contact with a thin layer of the incompressible hydraulic drive fluid 16, 16 are displaced by the piston 32 to cause the piston assembly 7 to vibrate in the cylinder tube 6. [

The floating piston (10) is centered in the main piston (8) and thereby guided concentrically. The main piston 8 is also slidably mounted within the cylinder tube 6 and sealed with the cylinder tube 6 by a radial hydraulic seal 20, such as a V-piston ring. The incompressible hydraulic drive fluid 16 disposed in the space between the floating piston 10 and the main piston 8 is passed through a duct 26 through which any leaked hydraulic fluid through the seal 20 is supplied, And a storage tank 28 in which the replenishment hydraulic drive fluid 16 shown in FIG. 2 is stored.

Referring to Figure 5, the storage tank 28 is configured so that any leakage of the hydraulic drive fluid 16 in the hydraulic seal 20 during use of the compressor piston 4 will cause the supplementary flow of the drive fluid 16 10 to create a leak cycle return line in the space between the pistons 8, The main piston 8 has a hydraulic fluid replenishing supply valve 24 fluidly connected to the reservoir tank 28 by conduits 38, The valve 24 is deflected to its closed position by a helical spring 22 or cup spring 22 acting thereon. However, if the pressure on the gas side of the first seal 18 increases due to the leakage of the drive fluid 16 through the seal 20, the floating piston 10 is pressed against the main piston 8 , A supplemental supply system is activated through the actuating unit 12 connected to the valve 24. [ The valve 24 is opened by the actuation unit 12 and the drive fluid 16 is pumped by the pump 48 from the reservoir 28 through the open valve 24 along the conduits 50 and 38, And is pumped along a diagonal conduit 36 that extends directly into the space between the main piston 8 and the floating piston 10. Thus, a constant depth of the hydraulic drive fluid 16 is maintained between the floating piston 10 and the main piston 8. The moving drive fluid 16 may be pumped back into the space between the floating piston 10 and the main piston 8 at any stage of the process. However, in the embodiment shown in the drawings, the pump 48 is activated when the piston assembly 7 is disposed below the cylinder tube 6, i.e., in the non-compression phase.

The pressure between the gas side of the floating piston 10 and the incompressible hydraulic fluid 16 is designed to be uniformly balanced. The pre-stress tension of the spring 22 on the operating unit 12 corresponds to the weight of the floating piston 10 and the frictional force generated between the cylinder tube 6 and the gas seal 18. [ The pressure difference between the side of the floating piston 10 in contact with the gas 14 and the side in contact with the hydraulic fluid 16 is less than 2 Bar and the small radial force between the floating piston 10 and the seal 18 Will cause less wear and tear.

Therefore, the above-described system always tries to allow the first gas seal 18 to receive only the pre-tension pressure defined by this seal 18, in order to minimize wear of the seal 18. In a conventional compressor, the gas seal in contact with the compressed gas 14 is exposed to a pressure equivalent to the gas pressure causing the wear, while the piston assembly 7 is divided into two (i.e., the floating piston 10 and the main Piston 8), the gas seal 18 in the compressor 2 of the present invention is exposed to a reduced pressure of only 2 bar. Thus, the present invention significantly reduces the load on the gas seal 18. The hydraulic seal 20 is exposed to pressures similar to the pressures experienced in the prior art compressors but any leakage of the hydraulic fluid 16 is transmitted from the storage tank 28 along the conduit 36 to the piston 8, Since it is re-injected immediately again into the space of the system. An embodiment of the compressor 2 shown in Fig. 3 is similar to that of Fig. 3 except that in Fig. 3 the ionic liquid cushion 56 is provided between the piston assembly 7 and the gas 14 to be compressed. Which is basically the same as that of This is useful in embodiments where the hydraulic drive fluid 16 itself is an ionic liquid and may not be needed if the drive fluid 16 is LOHC. The ionic liquid cushion 56 is on top of the floating piston 10 and fills all of the dead space during the compression phase. The ionic liquid cushion 56 comprises a low vapor pressure fluid, and may be composed of any pure ionic liquid, or a mixture of ionic liquid and LOHC.

The advantage of the compressor 2 lies in the extended wear time (> 20.000 h) for the piston seals 18, 20, due to the very good lubrication produced between the pistons 8, 10 and the cylinder tube 6. This provides excellent corrosion protection and mechanical protection against compressor knocking, thereby reducing noise emissions. Another benefit includes longer service life leading to lower maintenance costs. This improves plant availability, and the lower contact pressure forces further reduce the requirements for the opposite contact surfaces, again minimizing the maintenance cost.

Claims (15)

An apparatus for compressing a first fluid,
A piston assembly comprising a piston cylinder and a piston assembly slidably mounted therein, the piston assembly comprising a first piston defining a space defined therein for receiving a second fluid used to compress a first fluid, And a second spaced piston member and means for supplying a second fluid to a space between the first and second piston members
Fluid compression device. The method according to claim 1,
The apparatus includes a storage tank configured to store the second fluid therein, wherein the means for supplying the second fluid to a space between the first and second piston members comprises a pump and the first and second At least one second fluid supply conduit extending between a space between the piston members and the storage tank and to which the second fluid is supplied, preferably the pump is activated during the non-compression phase, And the second fluid disposed in the space between the first piston member and the second piston member is fluidly connected to the storage tank through at least one second fluid leakage conduit
Fluid compression device. 3. The method of claim 2,
Wherein the second piston member comprises a valve configured to control the flow of the second fluid into the space between the first and second piston members through the at least one second fluid supply conduit, The valve comprises deflecting means configured to deflect the valve in a closed configuration in the second fluid supply conduit, more preferably the deflecting means comprises a spring, optionally a spiral spring or cup spring
Fluid compression device. The method of claim 3,
Wherein the second piston member comprises actuating means configured to actuate the valve in response to a change in pressure for the first seal or in response to a position of the first piston member relative to an actuation setpoint, Wherein the pump is configured to pump the second fluid from the storage tank through an open valve activated by the actuating means and into a space between the first and second piston members along the at least one conduit
Fluid compression device. 5. The method of claim 4,
The actuating means is configured to open the valve when the pressure for the first seal increases and to activate the pump to pump the second fluid through the valve and / Closing the valve when the pressure on the seal decreases and deactivating the pump to prevent pumping of the second fluid; The first piston member is urged toward the second piston member when the pressure on the first fluid side of the first seal increases due to the leakage of the second fluid through the second seal and / The actuating means being configured to open the valve; And / or the pre-stress tension of the biasing means applied to said actuating means is substantially equal to the weight of said first piston member and the frictional force generated between said cylinder tube and said first seal
Fluid compression device. 5. The method of claim 4,
Wherein the actuating means is configured to open the valve when the position of the first piston member reaches the operating set point, and / or the actuating means moves the position of the first piston member past the operating set point Is configured to close the valve
Fluid compression device. 7. The method according to any one of claims 1 to 6,
Wherein the first piston member is configured to vibrate in the cylinder tube and is sealed together with the cylinder tube by a first radial seal, optionally a stem seal or a piston seal, And is sealed together with the cylinder tube by a second radial seal, alternatively a stem seal or a piston seal, said first piston member being mounted substantially centrally on said second piston member Thereby being guided in a concentric manner
Fluid compression device. 8. The method according to any one of claims 1 to 7,
The first fluid to be compressed is in contact with one side of the first piston member and the second fluid is in contact with the other side of the first piston member and preferably the device is in use during use of the compressor piston And wherein any leakage of the second fluid in the second seal is automatically balanced by the supplemental flow of the second fluid, so that a leakage cycle return line in the space between the first piston member and the second piston member
Fluid compression device. 9. The method according to any one of claims 1 to 8,
Wherein the second piston member comprises at least one conduit extending radially outwardly from the valve to a space between the first and second piston members, and preferably the at least one conduit extends from the valve to the first and second piston members, And extending diagonally into the space between the second piston members
Fluid compression device. 10. The method according to any one of claims 1 to 9,
Wherein the pressure difference between the side of the first piston member in contact with the first fluid and the side in contact with the second fluid is less than 75 Bar, 50 Bar, 25 Bar, 15 Bar, 10 Bar, 5 Bar or 3 Bar, The compressor piston is configured to increase the pressure of the first fluid from 100 bara to 1500 bara
Fluid compression device. 11. The method according to any one of claims 1 to 10,
Wherein the first fluid comprises a gas such as natural gas, fuel gas, hydrogen, gaseous hydrocarbons, liquefied combustion gases, inert gases such as nitrogen, helium, oxygen, and argon, or mixtures thereof, Wherein the second fluid comprises an ionic liquid, a LOHC (liquid organohydrogen storage material), semiheavy water (HDO), oxidized deuterium (heavy water), water or a hydraulic oil , Or a mixture thereof
Fluid compression device. 12. The method according to any one of claims 1 to 11,
The apparatus is configured to use an ionic liquid cushion disposed between the piston assembly and the first fluid to be compressed, and preferably the ionic liquid cushion comprises a substantially pure ionic liquid, or an ionic liquid and an LOHC Or a substantially pure ionic liquid, or a mixture of ionic liquid and LOHC
Fluid compression device. 13. The method according to any one of claims 1 to 12,
The apparatus comprises:
A vibration compressor and / or a hydraulically driven compressor, and / or
A liquid piston compressor and / or an ion compressor, and / or
Once the compressor or multistage compressor, and / or
A plunger configured to vibrate within the housing and operatively connected to the one or more displacement pistons configured to compress the first fluid therein by displacing the second fluid to and from the compressor piston, Wherein the vibration of the displacement piston or each displacement piston driven by the plunger is facilitated by a lubricant supplied through the at least one inlet into the housing, the lubricant being selected from the group consisting of hydraulic oil, LOHC or ionic liquid, Mixtures containing
Fluid compression device. A method for compressing a first fluid,
CLAIMS What is claimed is: 1. A method comprising: providing a first fluid into a piston of a compressor including a piston cylinder and a piston assembly slidably mounted therein, the piston assembly having a space configured to receive a second fluid used to compress the first fluid Said first and second spaced piston members defining between said first and second spaced piston members,
Supplying a second fluid to a space between the first and second piston members, and compressing the first fluid
Fluid compression method. 15. The method of claim 14,
The method comprises using an apparatus according to any one of claims 1 to 13
Fluid compression method.

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