EA020177B1 - Method of removing carbon dioxide from a fluid stream and fluid separation assembly - Google Patents

Abstract

The invention relates to a method of removing carbon dioxide from a fluid stream by a fluid separation assembly. The fluid separation assembly has a cyclonic fluid separator with a tubular throat portion arranged between a converging fluid inlet section and a diverging fluid outlet section and a swirl creating device. The separation vessel has a tubular section positioned on and in connection with a collecting tank. In the method, a fluid stream with carbon dioxide is provided. Subsequently, a swirling motion is imparted to the fluid stream so as to induce outward movement. The swirling fluid stream is then expanded such that components of carbon dioxide in a meta-stable state within the fluid stream are formed. Subsequently, the outward fluid stream with the components of carbon dioxide is extracted from the cyclonic fluid separator and provided as a mixture to the separation vessel. The mixture is then guided through the tubular section towards the collecting tank while providing processing conditions such that solid carbon dioxide is formed. Finally, solidified carbon dioxide is extracted.

Description

The invention relates to a method for removing carbon dioxide from a fluid stream. In particular, embodiments of the present invention relate to a method for removing carbon dioxide from a natural gas stream. The invention also relates to a device for separating a fluid.

Natural gas from a storage or production tank typically contains carbon dioxide (CO ₂ ). Such natural gas is referred to as acid gas. Another component designated as acidic in the fluid stream is hydrogen sulfide (H ₂ §). A fluid stream without any of the above acidic components is referred to as a neutral fluid.

CO ₂ contributes to corrosion inside pipelines. In addition, legal and commercial requirements regarding the maximum concentration of CO ₂ in a fluid stream may be applicable in some areas. Therefore, it is desirable to remove CO ₂ from the acidic fluid stream.

Fluid neutralization processes, i.e. the process of removing acidic components like carbon dioxide from a fluid stream is known in the art. Such processes typically include at least one process of chemical absorption, physical absorption, adsorption, low temperature distillation, referred to as cryogenic separation and membrane separation.

The use of such methods to remove carbon dioxide from a fluid stream is complex and expensive.

The objective of the invention is to provide a method for removing carbon dioxide from a fluid stream, which acts more efficiently than the methods mentioned above. To solve this problem, an embodiment of the invention is proposed, which is a method of removing carbon dioxide from a fluid stream by means of a fluid separation device including a cyclone fluid separator comprising a neck portion located between a tapering section for receiving a fluid and an expanding section for a fluid outlet, and a turbulence assembly configured to create a vortex motion of a carbon dioxide-containing fluid yes, inside at least a portion of the cyclone fluid separator, the tapering fluid receiving section comprises a first inlet for fluid components, and the expanding fluid discharge section contains a first carbon dioxide depleted fluid outlet and a second outlet for carbon dioxide enriched fluid;

a separation tank having a first section associated with the collection tank, the first section is provided with a second inlet connected to the second outlet of the cyclone fluid separator, and the collection tank is provided with a third outlet for hardened carbon dioxide, wherein said separation tank operates with a combination of pressure and temperature, which is located at or near the interface between the region of the coexistence of vapor / liquid / solid phase (1Yb) and the region of coexistence (1Ya ) vapor / solid phase;

in the method, a fluid stream is directed to the first inlet channel, the fluid stream contains carbon dioxide;

imparting a swirling motion to the fluid stream in such a way as to stimulate the removal of at least one component from the condensed components and the cured components in the fluid stream in the lower flow of the assembly to create turbulences and to form an outgoing fluid stream;

expanding the vortex fluid stream in such a way as to form liquefied carbon dioxide components in a metastable state in the fluid stream and stimulate the removal of liquefied carbon dioxide components in a metastable state under the influence of vortex motion;

extracting a fluid outlet stream containing liquefied carbon dioxide components in a metastable state from said cyclone fluid separator through a second outlet channel;

directing the extracted fluid exit stream as a mixture to the separation tank through a second inlet;

directing the mixture through the first section of the separation tank to the collection tank, while providing the processing conditions in the first section so that the hardened carbon dioxide is formed from the components of liquefied carbon dioxide in a metastable state;

hardened carbon dioxide recovery through a third exhaust channel.

Another aspect of the invention is also a fluid separation device that removes carbon dioxide from a fluid stream; this fluid separation device comprises a cyclone fluid separator comprising a neck portion located between a tapering section for receiving a fluid and an expanding section for discharging a fluid environment and node

- 1 020177 to create vortices, configured to create a vortex of a fluid containing carbon dioxide inside at least a portion of the separator, the tapering section for receiving fluid contains a first inlet for fluid components, and an expanding section for releasing fluid the medium comprises a first carbon dioxide depleted fluid outlet and a carbon dioxide enriched fluid outlet;

a separation tank having a first section associated with a collection tank, this section is provided with a second inlet connected to a second outlet of a cyclone fluid separator, and a collection tank is provided with a third outlet for hardened carbon dioxide, wherein said separation tank is operated under a combination of pressure and temperature, which is located at or near the interface between the region of the coexistence of vapor / liquid / solid phase (1Yb) and the region of coexistence (1Ya ) vapor / solid phase;

wherein the fluid separation apparatus is adapted to receive a fluid stream containing carbon dioxide into the first inlet;

impart a swirling motion to the fluid stream in such a way as to stimulate the removal of at least one component from the condensed components and the cured components in the fluid stream in the lower flow of the assembly to create turbulences and to form an effluent fluid stream;

expand the vortex fluid stream in such a way as to form liquefied carbon dioxide components in a metastable state in the fluid stream and to stimulate the removal of liquefied carbon dioxide components in a metastable state under the influence of vortex motion;

extract a fluid outlet stream containing the indicated components of liquefied carbon dioxide in a metastable state from the cyclone fluid separator through a second outlet channel;

provide the recovered fluid exit stream as a mixture to the separation tank through a second inlet;

to direct the mixture through the first section of the separation tank to the collection tank, while providing the processing conditions in the first section so that the hardened carbon dioxide is formed from the components of liquefied carbon dioxide in a metastable state;

make it possible to recover the hardened carbon dioxide through the third exhaust channel.

Throughout the description, the term fluid is used. This term is used to refer to a liquid and / or gas.

Below will be described, by way of example only, embodiments of the invention with reference to the accompanying schematic drawings, in which the corresponding symbols indicate the corresponding details, where:

FIG. 1 schematically depicts a longitudinal sectional view of a cyclone fluid separator that may be used in embodiments;

FIG. 2 schematically depicts a cross-section of a separation tank that can be used in embodiments;

FIG. 3a, 3b depict an example phase diagram of natural gas containing carbon dioxide, which schematically shows various embodiments of the method;

FIG. 4-7, 8a and 8b schematically depict other embodiments.

In FIG. 1 is a schematic longitudinal sectional view of a cyclone fluid separator 1 that can be used in embodiments of the present invention. Such a cyclone fluid separator is described in more detail in international patent application AO 03/029739. It should be understood that various types of cyclone fluid separators can be used in embodiments of the invention, for example a cyclone fluid separator described in AO 99/01194, AO 2006/070019 and AO 00/23757.

The cyclone fluid separator 1 comprises a tapering fluid receiving section 3, an expanding fluid discharge section 5 and a tubular neck portion 4 located between the tapering fluid receiving section 3 and the expanding fluid discharge section 5. The cyclone fluid separator 1 also includes a turbulence assembly, for example a significant number of turbulence blades 2, configured to create a vortex fluid motion within at least a portion of the cyclone fluid separator 1.

The cyclone fluid separator 1 contains a pear-shaped central element 11 on which blades 2 are mounted to create a swirl and which is located coaxially with the central axis I of the cyclone separator 1 and inside the cyclone separator so that an annular path for flowing between the central element 11 and the housing 20 is created separator.

The width of the annular gap is designed so that the cross-sectional area of the annular gap gradually decreases in the lower flow of the blades 2 to create a swirl,

- 2 020177 so that when applied, the fluid velocity in the annular gap gradually increases and reaches supersonic speed in the lower flow of the blades 2 to create a vortex.

The cyclone separator 1 also contains a tubular neck portion 4, from which, when applied, a vortex fluid stream is discharged into an expanding fluid separation chamber 5, which is provided with a central primary outlet 6 for gaseous components and an external secondary outlet 7 for fluid components capable of condensation. The central element 1 has a substantially cylindrical elongated tail section 8 on which the assembly of the blades 19 is mounted to straighten the flow. The central element 11 has the largest external width or diameter 2K _{O max} , which is greater than the smallest internal width, or the diameter 2K _{P t1P of the} tubular _neck portion 4.

The tubular neck portion 4 comprises a portion of an annular gap 3 having the smallest cross-sectional area. The maximum diameter of the central element 1 is greater than the minimum diameter of the tubular neck portion 4.

The tapering section 3 for receiving fluid contains a first inlet channel 10. The expanding section 5 for discharging a fluid contains a first outlet channel 6 and a second outlet channel 7.

Below, the purpose of the various components of the cyclone fluid separator 1 with respect to the case in which the cyclone fluid separator 1 is used to separate carbon dioxide from a fluid stream containing carbon dioxide in accordance with an embodiment of the invention will be explained.

A fluid stream containing carbon dioxide is supplied through a first inlet channel 10 to a tapering section 3 for receiving a fluid. In an embodiment of the invention, the fluid stream contains a proportion of carbon dioxide in mole percent of more than 10%. Swirl blades 2 create circulation in the fluid stream and are oriented at an angle α with respect to the central axis of the cyclone fluid separator 1, i.e. an axis around which the cyclone fluid separator 1 is almost axisymmetric. The vortex fluid stream then expands to high speeds. In embodiments of the invention, a series of blades 2 for creating a swirl is located in the neck portion 4. In other embodiments of the invention, a series of blades 2 for creating a swirl is located in the tapering section 3 for receiving fluid. On the other hand, the central element 11 has the largest external width or diameter 2K _{O max} , which is greater than the smallest internal width, or the diameter 2K _{P t1P of the} tubular _neck portion 4.

In embodiments of the invention, the vortex fluid stream has a transonic velocity. In other embodiments of the invention, the vortex fluid flow can achieve supersonic speed. Expansion is fast. With respect to expansion, two timelines can be defined.

The first timeline relates to the mass transfer time of Ts, i.e. to the time that is associated with a return to equilibrium conditions. _1ch depends on the density of the interphase surface in a two-phase system, the diffusion coefficient between two phases, and the magnitude of the deviation from equilibrium. One _time for a liquid-to-solid transition is usually two orders of magnitude larger than for a vapor-to-liquid transition.

The second timeline refers to the duration of the expansion of 1 _{| her} , the fluid in the device. 1 _{| its} , is associated with the average fluid velocity in the device and the length along the axis of the device along which the fluid moves. The extension is designated as fast when D / 1 _ge8 > 1.

Due to the rapid expansion, which causes a high fluid flow rate, the vortex fluid flow can reach a temperature below 200 K and a pressure below 50% of the pressure in the first inlet channel 10 of the tapering section 3 for receiving the fluid. As a result of the above expansion, carbon dioxide components are formed in a metastable state in a fluid stream. In the case where the fluid stream in the receiving section 3 is a gas stream, carbon dioxide components will form as liquefied carbon dioxide components. In the case where the fluid stream in the receiving section 3 is a liquid stream, hydrocarbon vapors will form, while most of the carbon dioxide components remain in liquid form. In the tubular neck portion 4, the fluid stream may be stimulated to expand further to achieve a higher speed, or may be maintained at substantially constant speed.

In the first case, i.e. as the fluid flow expands to a higher speed, the aforementioned formation of carbon dioxide components continues, and the particles will increase mass. Preferably, the extension is extended to the region of coexistence of the solid state (region 1Aa or 1Yb in Figs. 3a, 3b). However, curing will be delayed with respect to the equilibrium state, since the phase transition from a liquid to a solid state is associated with a barrier of free energy of formation. As will be further discussed with reference to FIG. 3a, 3b, part of the carbon dioxide may solidify.

- 3 020177

In the case where the fluid flow is maintained essentially at a constant speed, the formation of the carbon dioxide component practically ceases after a certain relaxation time has passed. In both cases, namely, by expanding the fluid flow to a higher speed and maintaining the fluid flow at a substantially constant speed, centrifugal action causes carbon dioxide particles to shift to the outer circumference of the flow cross section adjacent to the inner wall of the cyclone separator body 1 fluid, so as to form an effluent of the fluid. In this case, the fluid outlet stream is a carbon dioxide enriched fluid stream, the carbon dioxide components in it are liquefied and / or partially cured.

In the lower flow of the tubular neck portion 4, an effluent of a fluid containing carbon dioxide components in the aforementioned metastable state is recovered from the cyclone fluid separator 1 through a second outlet 7 of the cyclone fluid separator 1. Other components in the fluid stream that is not part of the above fluid outlet stream are removed from the cyclone fluid separator 1 through the first outlet 6 of the cyclone separator = cyclone fluid separator 1.

In FIG. 2 is a schematic cross-sectional view of a separation tank 21 that can be used in embodiments of the invention. The separation tank 21 has a first section, which is then referred to as a tubular section 22, which, when used, is positioned essentially vertically on the collection tank 23 and connected to it. The collection tank 23 is provided with a third outlet channel 28 and a fourth outlet channel 26. The tubular section 22 is provided with a second inlet channel 25 and a fifth outlet channel 29. The second inlet channel 25 is connected to the second outlet channel 7 of the cyclone fluid separator 1. In an embodiment, the second inlet channel 25 is adapted to provide a tangential fluid flow to the separation tank 21, for example, the second inlet channel 25 is tangential to the circumference of the separation tank 21. The separation tank 21 also comprises a cooling unit, in FIG. 2 schematically represented by numeral 31, and a separation unit, in FIG. 2 is schematically represented by numeral 33.

Below, the purpose of the various components of the separation tank 21 will be explained with respect to the case in which the separation tank 21 is used in a method for removing carbon dioxide from a fluid stream in accordance with an embodiment of the invention.

The cooling unit 31 is configured to provide predetermined temperature conditions in the separation tank 21. The temperature conditions are such that they allow solidification of the carbon dioxide-rich fluid that is introduced into the separation tank 21 through the second inlet channel 25 as a mixture. In other words, the temperature inside the separation tank 21 should remain below the solidification temperature of carbon dioxide, which depends on the pressure in the separation tank 21.

Inside the separation tank 21, the mixture containing carbon dioxide coming from the second outlet channel 7 of the cyclone fluid separator 1 is separated into at least three fractions. These fractions are the first fraction of gaseous components, the second fraction of hydrocarbons, mainly in the liquid state, and the third fraction of carbon dioxide, mainly in the solid state.

The first fraction is formed by gaseous components that are drawn together with liquids flowing from the second outlet channel 7. The cooling unit 31 is configured to maintain the temperature inside the separation tank 21 below the solidification temperature of the fluid. The gaseous components do not contain much carbon dioxide, since most carbon dioxide will be dissolved in the mixed liquid, as will be explained in more detail when referring to FIG. 3. Gaseous components depleted in carbon dioxide can leave the separation tank 21 through the fifth exhaust channel 29.

The tank 21 may be provided with one or more inlet channels 25, which are located tangentially to the perimeter of the vertical section 22, so that a rotational flow occurs in section 22. In addition, the upper vent pipe 29 can be elongated in the form of a vertical pipe in the specified vertical section 22 in such a way that it forms the so-called discharge nozzle. The end of said discharge nozzle is in a lower vertical position compared to the vertical position of one or more inlet channels 25. This will be explained in more detail below with reference to FIG. 7.

The end of the discharge nozzle (i.e., the lowermost part of the exhaust pipe 29) is below the inlet channel 25, which allows the components that are introduced through the inlet channel 25 to separate before reaching the end of the discharge nozzle. So this distance is provided to prevent liquids and solid particles from entering the discharge nozzle. Liquids and solid particles will be forced to deflect to the outer perimeter due to rotational forces and will not be introduced into the vent pipe 29.

- 4 020177

Sections 22 and 23 of reservoir 21 can be physically separated by a conical turbulence damper, the outer perimeter of which has a gap C with respect to the inner perimeter of the vertical section 22. The size of this gap C can usually be in the range from 0.05 to 0.3 of the inner diameter of the section 22. This will be explained in more detail below with reference to FIG. 7.

As a result of the hardening of carbon dioxide from the liquid inside the mixture, phenomena that will be explained in more detail with respect to FIG. 3, a mixture that no longer holds gaseous components can be separated into a liquid component containing a hydrocarbon and a solid state carbon dioxide component through a separation unit 33. Possible separation nodes 33 include a gravity separator, centrifuge and hydrocyclone. In the case where a gravity separator is used, it preferably contains a significant number of plates arranged in a stack. In the case where a centrifuge is used, it preferably comprises a stack of conical baffles in the rotor. The separation unit 33 in the separation tank 21 is configured to allow the hydrocarbon liquid components enriched in carbon dioxide to leave the separation tank 21 through the fourth exhaust channel 26 and allows the hardened carbon dioxide to leave the separation tank 21 through the third exhaust channel 28.

In an embodiment, the fluid separation apparatus also comprises a screw conveyor or screw discharge unit 35 connected to the third outlet channel 28. The screw discharge unit 35 is configured to recover solidified carbon dioxide from the separation tank 21.

In yet another embodiment, the inner surfaces of the elements of a device for separating a fluid open to a fluid, i.e. the cyclone fluid separator 1, the separation reservoir 21 and one or more pipes or the like connected to the second outlet channel 7 of the cyclone fluid separator 1 and the second inlet channel 25 of the separation reservoir 21 are provided with a release coating. The release coating prevents adhesion of the cured fluid components, i.e. carbon dioxide, on the above internal surfaces. Such adhesion would reduce the efficiency of the fluid separation device.

In FIG. 3a, 3b shows an example phase diagram of natural gas containing carbon dioxide, which schematically shows various embodiments of the method in accordance with this invention. Phases are presented as a function of pressure in bars (1 bar = 100 kPa) and temperature in degrees Celsius. In this particular case, natural gas contains 71 mol.% CO ₂ . In addition, natural gas contains 0.5 mol.% Nitrogen (Ν ₂ ), 0.5 mol.% Hydrogen sulfide (H ₂ §), 27 mol.% C1, i.e. hydrocarbons with a single carbon atom in their molecules, and 1 mol.% C2, i.e. hydrocarbons with two carbon atoms in their molecules. The phases are indicated as follows: V = steam, b = liquid, C = solid state CO ₂ . The regions of different coexisting phases are separated by the calculated interphase boundaries.

In FIG. 3a, the fluid flow conditions in the first inlet channel 10 of the cyclone fluid separator 1, shown schematically in FIG. 1 correspond to the coordinates of 80 bar (8 MPa) and -40 ° C, denoted as [8TAKT] in the diagram of FIG. 3a. The isentrop along arrow A is in the liquid region (II), while the isentrop along arrow B is in the vapor / liquid coexistence region (III). As a result of expansion in the region of coexistence (III), a metastable state in the liquid / vapor mode can be achieved when following arrow B until a phase transition occurs under certain conditions of supersaturation. The resulting evaporation process will then restore equilibrium conditions. An additional expansion of the fluid flow along arrow C may cause the fluid to achieve a metastable state in the coexistence region (I vapor / liquid / solid phase or in the coexistence region (Sha) vapor / solid phase. Even if there is a phase transition along the expansion path indicated by arrow C for the formation of solid-state carbon dioxide will not occur immediately, the proportion of carbon dioxide in the vapor will decrease, along with the fact that more carbon dioxide dissolves in the liquid. According to the invention, the fluid stream can be separated by a cyclone fluid separator, for example, such a cyclone fluid separator as described in international patent application UO 2006/070019, into a carbon dioxide enriched fluid stream and a dioxide depleted fluid stream carbon, at the end of the expansion trajectory indicated by arrow C. The separated fluid enriched in carbon dioxide is in a nonequilibrium state that will only last for a limited period of time, oryadka 10 ms. Therefore, the carbon dioxide enriched fluid is re-compressed in the second outlet channel 7 of the expanding outlet section 5 of the cyclone fluid separator 1 and is discharged through the second outlet channel 7 into the separation tank 21, preferably within a specified period of time during which the metastable state exists. Interruption of the indicated metastable state leads to the formation of a solid, which in practice means that the dissolved carbon dioxide in the liquid solidifies. Hardening of carbon dioxide releases latent heat, causing an increase in the temperature of the fluid. Therefore, the separated carbon dioxide enriched fluid that is introduced into the separation tank 21 can be cooled.

- 5 020177 den, in order to ensure that the fluid remains in the area of coexistence of vapor / solid phase or vapor / liquid / solid phase. The indicated process of cooling and re-compressing a carbon dioxide-enriched fluid is indicated by an arrow Ώ. In embodiments of the invention, the additional solidification process takes place in the separation tank 21. The state of the fluid when the equilibrium is again reached inside the separation tank 21 is indicated as [ΕΝΏ]. The hardened carbon dioxide is removed through the third exhaust channel 28, as described above.

In FIG. 3b, the fluid flow conditions in the first inlet 10 of the cyclone fluid separator 1, shown schematically in FIG. 1 correspond to coordinates of approximately 85 bar (8.5 MPa) and approximately 18 ° C, denoted as [8TAK.T] in the diagram of FIG. 3b. An isentrop along arrow A 'is in the region (I) of the vapor, while an isentrop along arrow B' is in the region of (III) vapor / liquid coexistence. As a result of expansion in the region of coexistence (III), a metastable state in the liquid / vapor mode can be achieved when following arrow B ', until a phase transition occurs under certain conditions of supercooling.

The resulting condensation process will then restore equilibrium conditions. An additional expansion of the fluid flow along arrow C 'can cause the fluid to reach a metastable state in the coexistence region ALC (vapor / liquid / solid phase) or in the coexistence region CSa) vapor / solid phase. Even along the expansion trajectory indicated by arrow C ', a phase transition for the formation of solid state carbon dioxide will not occur immediately. In embodiments of the invention, the fluid stream is separated by a carbon dioxide enriched fluid separator 1 into a carbon dioxide rich fluid stream and a carbon dioxide depleted fluid stream at the end of the expansion path indicated by arrow C ', the process described above with reference to FIG. 1. In addition, further details regarding such a process can be found in international patent application νθ 03/029739. The separated fluid enriched in carbon dioxide is in a nonequilibrium state that will only persist for a limited period of time, on the order of 10 ms. Therefore, the carbon dioxide enriched fluid is re-compressed in the expanding outlet section 5 of the cyclone fluid separator 1 and discharged through the second outlet channel 7 into the separation tank 21, preferably within a specified period of time during which the metastable state exists. Interruption of this metastable state results in the formation of solid-state carbon dioxide from the liquefied portion of the fluid stream. Hardening of carbon dioxide releases latent heat, causing an increase in the temperature of the fluid. Therefore, the separated carbon dioxide-enriched fluid that is introduced into the separation tank 21 can be cooled in order to ensure that the fluid remains in the vapor / solid phase or vapor / liquid / solid phase coexistence region. The specified process of cooling and re-compressing a fluid enriched in carbon dioxide is indicated by an arrow Ώ '.

In embodiments of the invention, the solidification process takes place in the separation tank 21. The state of the fluid when the equilibrium is again reached inside the separation tank 21 is indicated as [ΕΝΏ]. Again, the hardened carbon dioxide is removed through the third exhaust channel 28, as described above.

For the examples presented above with reference to FIG. 3a and 3b, the maximum solid-state fraction of carbon dioxide for a given temperature T is obtained at a pressure P crossing the interphase boundary between the regions LUS СУЬ) and УС СУа).

As explained above, the purpose of the separation tank 21 is to remove the maximum amount of carbon dioxide in the solid phase. Therefore, in accordance with an embodiment, the separation tank 21 operates at or near the pressure P and the temperature T at the interface between the regions LUS DUL) and SUS CUa). This interface is shown in FIG. 3a and 3b.

In the example of FIG. 3a and 3b, this interphase boundary is intersected by an arrow которая, which represents the process of cooling and re-compressing a carbon dioxide-enriched fluid, as occurs in the separation tank 21. As shown, the state of the fluid at the newly reached equilibrium inside the separation tank 21 is denoted by [ ΕΝΏ]. In accordance with the embodiment described here, [ΕΝΏ] is selected at or near the interface between the regions LUS (GUY) and USS SUA). This is done for the reason that the amount of solid-state carbon dioxide is maximum at this interface.

In this embodiment, the term near the interface is used to indicate a possible deviation in temperature of ± 5 ° C with respect to the indicated interphase boundary and a possible deviation in pressure of ± 2 or ± 5 bar (200 or 500 kPa) or a deviation of 10 or 20% by relative to the indicated interphase boundary.

Thus, in accordance with an embodiment, the separation tank 21 operates at a pressure P within 5 bar (500 kPa) and a temperature T within 5 ° C. from the interphase between the regions LUS DUL) and US (GUa).

These conditions can be controlled by controlling the pressure and temperature inside.

- 6 020177 of the separation tank 21. The temperature in the separation tank 21 can be controlled by applying a cooling unit 31. The pressure in the separation tank 21 can be controlled by a pressure control valve that is located in the gas pipe 29.

In accordance with an embodiment, the separation tank 21 operates at a combination of pressure and temperature that occurs at the interface between or near the coexistence region (IV) of the vapor / liquid / solid phase and the region of coexistence (IV) of the vapor / solid phase.

In accordance with the examples given with reference to FIG. 3a and 3b, the separation tank 21 can operate at a pressure in the range of 5-25 bar (0.5-2.5 MPa). The estimated temperature range for these examples is in the range of -70 to -90 ° C.

In FIG. 4-6 schematically depict another embodiment in which a screw conveyor or screw discharge unit 35 is replaced by a perforated screen 40. In FIG. 4 shows a side view of such a perforated screen 40, while in FIG. 5 shows a top view of such a perforated screen in accordance with a possible embodiment. FIG. 6 schematically depicts such a perforated screen 40 in combination with a separation tank 21.

According to this embodiment, the hardened carbon dioxide is removed from the separation tank 21 by means of a perforated screen 40 having conical openings / slots or conical openings. The perforated screen 41 may be heated, and a pressure difference between the supply side 42 and the withdrawal side 43 can be maintained so that the pressure on the supply side is always higher than or equal to the pressure on the withdrawal side.

The perforated screen 40 may be provided with a plurality of perforations or holes 41. The holes 41 may be rectangular holes, holes formed in the form of slots, or may be circular holes, as shown in FIG. 5.

The hardened carbon dioxide particles that are discharged from the separation tank 21 through the third exhaust channel 28 are transported to the supply side 42 of the perforated screen 40, as shown in FIG. 4. The hardened carbon dioxide particles move through the openings 41 from the supply side 42 to the withdrawal side 43 of the perforated screen 40. The size and shape of the holes 41 are such that when using the hardened carbon dioxide particles fill the holes 41 and form a layer of hardened carbon dioxide, thereby preventing movement gases and liquids from the supply side 42 to the selection side 43.

In order to form such a layer of hardened carbon dioxide and thereby avoid leakage of liquid or gas through the openings 41 from the supply side 42 to the extraction side 43, the openings 41 may have a narrowed or conical shape, i.e. the holes 41 have a cross section on the supply side 41 larger than the cross section of the hole 41 on the withdrawal side 43. This is shown in FIG. 4.

The convergence angle α of these holes 41 may be in the range between 5 and 30 ° with respect to the longitudinal axis 44 of the hole 41. According to another embodiment, the convergence angle α of the holes 41 is in the range between 10 and 20 °. A typical inlet size Ό42 of the hole 41 (for example, the diameter of the circular holes 41) on the supply side 42 of the perforated screen 40 may be at least 2 times larger than the typical grain size of the hardened carbon dioxide.

A typical exit dimension Ό43 of the hole 41 (for example, the diameter of the circular holes 41) on the sampling side 43 may be approximately equal to the average grain size of the hardened carbon dioxide. However, in accordance with another embodiment, a typical exit dimension Ό43 of the hole 41 on the extraction side 43 is substantially smaller than the average grain size of the hardened carbon dioxide. The diameter Ό43 of the circular hole 41 on the outlet side may be in the range from 0.5 to 5 mm, although preferably between 1 and 3 mm.

The depth Ό41 of the holes 41, measured in the direction of the longitudinal axis 44, typically can be twice as large as the input size Ό42 of the hole 41. However, the depth Ό41 of the holes 41 can more than double the input size Ό42 of the hole 41. Preferably, the depth глуб41 is less than 5 times the input size Ό42.

The narrowed shape and dimensions of the holes 41 provide the opportunity for the formation of a dense packing of particles of hardened carbon dioxide particles in the holes 41 and possibly above them. When applied, hardened carbon dioxide particles will be present in the openings 41 and on the upper side of the perforated screen 40. The dense packing of the hardened carbon dioxide particles has a relatively low porosity and ensures that there are no flow paths for gases or liquids to leak through. through particles from the supply side 42 to the selection side 43.

In addition, blocking these flow paths in order to obtain an impermeable layer of hardened carbon dioxide on the perforated screen 40 can be created by providing means for applying a static pressure to the grains of hardened carbon dioxide. The term head is used to refer to a column or layer of liquid and solid particles that

- 7 020177 leads to the creation of pressure on solid particles on the perforated screen 40.

This increases the mutual contact pressure between the carbon dioxide grains and the carbon dioxide grains and the side walls of the openings 41. By increasing the cohesive and adhesive forces, the carbon dioxide layer becomes denser.

In order to allow the hardened carbon dioxide particles to travel through the openings 41 to the bleed side 43, the hardened carbon dioxide particles are melted on the bleed side 43. This can be done by maintaining a suitable temperature T43 on the bleeding side 43 and / or maintaining a suitable pressure P43 on the side selection 43.

The withdrawal pressure P43 on the withdrawal side 43 is controlled at a value that is typically 2 bar (200 kPa) lower than the pressure P42 on the supply side 42 and in the separation tank 21. Therefore, in the case where the separation tank 21 operates at a pressure of 20 bar (2 MPa) ), the pressure P42 on the supply side is approximately 20 bar (2 MPa), and the pressure P43 on the extraction side can be adjusted in such a way that it is approximately 10-18 bar (1.0-1.8 MPa).

The temperature T43 on the withdrawal side 43 of the perforated screen 40 can be selected in such a way that when the corresponding pressure is set, carbon dioxide is in the liquid phase. For example, for a typical pressure of 10-18 bar (1.0-1.8 MPa), the temperature can be selected between about -55 and 0 ° C.

The temperature on the bleed side can be adjusted by a temperature maintaining unit (not shown) or a unit that heats the perforated screen to a desired temperature inside the liquid phase of carbon dioxide to separate liquid carbon dioxide from the perforated screen 40 during melting.

As a result of temperature and pressure T43, P43 on the withdrawal side 43, the lower side of the formed carbon dioxide layer will melt, and the carbon dioxide will drip and can be collected in a suitable tank or the like.

The above embodiment provides an effective way of separating carbon dioxide. By finding carbon dioxide in the solid state inside the separation tank 21, carbon dioxide is separated, for example, from methane (which would otherwise be mixed with carbon dioxide in the liquid phase). At the same time, on the withdrawal side 43 of the perforated screen 40, carbon dioxide is provided in the liquid phase, allowing easy subsequent transportation and processing.

By using a perforated screen 40, a barrier for solid-state carbon dioxide is provided between the supply side 42 and the withdrawal side 43, allowing the creation and control of different conditions (pressure / temperature) on the withdrawal side and the separation side.

In FIG. 7 shows yet another embodiment.

The tank 21 may be provided with one or more inlet channels 25, which are located tangentially to the perimeter of the vertical section 22, so that a rotational flow occurs in section 22. In addition, the upper vent pipe 29 can be elongated in the form of a vertical pipe in the specified vertical section 22 in such a way that it forms the so-called discharge nozzle. The end of said discharge nozzle is in a lower vertical position compared to the vertical position of one or more inlet channels 25.

Sections 22 and 23 of the reservoir 21 can be physically separated by a conical deflector plate or a conical turbulence damper 30, the outer perimeter of which has a clearance C with respect to the inner perimeter of the vertical section 22. The size of this gap C can usually be in the range from 0.05 to 0, 3 from the inner diameter of section 22.

A conical turbulence suppressor 30 destroys the rotational flow from the first section 22 to the collection tank 23 to prevent turbulence in the collection tank

23.

Also, a conical turbulence suppressor can prevent the movement of gaseous components from the vertical section 22 to the collection tank 23 and deflects these gaseous components to the upper vent pipe 29.

A perforated screen 40 is now provided as part of the collection tank 23. When applied, a CO ₂ layer will be formed on the upper side of the perforated screen 40. The overflow wall 34 is formed to provide an overflow connection. The overflow connection allows liquids that will typically form on top of the CO ₂ layer to pass through the overflow wall 34 and to be discharged from the collection tank 23 through the fourth outlet channel 26.

In FIG. 8a schematically shows another embodiment. In FIG. 8a shows a reservoir 21 and two cyclone fluid separators 1 described above. However, it should be understood that instead of two, any suitable number of cyclone fluid separators 1 may be provided.

According to this embodiment, the fluid separation apparatus also includes a feedback line 81 which is connected on one side to the fourth outlet 26 and the other side is connected to an inlet of the feedback line of the cyclone fluid separator 1. The feedback pipe 81 also includes a pump Ρϋ.

- 8 020177

The carbon dioxide-rich hydrocarbon liquids that flow through the fourth exhaust channel 26 are pumped through the RI pump through a pipe 81 for feedback into the inlet of the feedback line of one or more cyclone fluid separators 1. In accordance with FIG. 8a, the inlet channel of the feedback line is located in the upper stream with respect to the pear-shaped central element 11 and is aligned with the normal inlet channel 82 of the cyclone fluid separators 1. However, the inlet of the feedback line may also be provided elsewhere, for example, in the middle of the cyclone fluid separator 1.

By providing such a pipe 81 for feedback, it is possible to achieve partial or even complete solidification of CO ₂ , without the need for additional cooling in the tank 21, where the temperature reaches its lowest value. Instead, the carbon dioxide enriched liquid hydrocarbon stream is first pumped to the supply pressure and combined with the stream in line 82 to create a new feed stream that is denoted as channel 81 + 82, and then the combined feed stream can be cooled to new temperature, which is lower than the temperature in the pipe 82, and higher than the temperature level in the tank 21. Typically, the difference between the temperature of the feed stream in the pipe 81 + 82 and the temperature in the tank 21 was 25 ° C. In order to perform cooling, a cooling unit 85 may be provided in conduit 81 + 82, as shown in FIG. 8b.

The first exhaust ports 6 of the cyclone fluid separators 1 may be combined with the fifth exhaust port 2 of the 9 tubular sections 22 to form an exhaust port 83. The fluid passing through the inlet port 81 of the cyclone fluid separator 1 may contain about 70% CO ₂ and 30% C _X H _U , while the fluid in the exhaust channel 83 may contain about 15% CO ₂ and 85% C _X H _U.

Additional remarks.

In accordance with an embodiment, a method is provided for removing carbon dioxide from a fluid stream by a fluid separation apparatus comprising a cyclone fluid separator comprising a neck portion located between a tapering fluid receiving section and an expanding fluid discharge section, and an assembly for create vortices, configured to create a vortex motion of a fluid containing carbon dioxide, inside at least part of the cyclone of the fluid separator, the tapering section for receiving the fluid contains a first inlet for fluid components, and the expanding section for discharging a fluid contains a first outlet for carbon depleted fluid and a second outlet for carbon dioxide enriched ;

a separation tank having a first section associated with the collection tank, said first section is provided with a second inlet channel associated with said second outlet channel of said cyclone fluid separator, and said collection tank is provided with a third outlet channel for hardened carbon dioxide.

The method includes providing a fluid stream to said inlet, said fluid stream comprising carbon dioxide;

imparting a swirling motion to the fluid stream in such a way as to stimulate the removal of at least one component from the condensed components and the cured components in the fluid stream in the lower flow of the assembly to create turbulences and to form an effluent fluid stream;

expanding the vortex fluid stream in such a way as to form the components of the liquefied carbon dioxide in a metastable state in the specified fluid stream and to stimulate the removal of these components of the liquefied carbon dioxide in the specified metastable state under the influence of the specified vortex motion;

extracting a fluid outlet stream containing said liquefied carbon dioxide components in said metastable state from said cyclone fluid separator through said second outlet channel;

providing said recovered fluid exit stream as a mixture to said separation tank through said second inlet;

directing said mixture through said first section of said separation tank to said collection tank, while providing processing conditions in said first section such that hardened carbon dioxide is formed from said liquefied carbon dioxide components in said metastable state;

recovering the hardened carbon dioxide through said third exhaust channel, the method also comprising forming a layer of hardened carbon dioxide extracted from the third exhaust channel 28, on the supply side 42 of the perforated screen 40 containing holes 41 elongated to the side

- 9 020177 selection 43;

applying such temperature and pressure conditions on the withdrawal side 43 of the perforated screen 40 to melt the carbon dioxide from the layer and collect the molten carbon dioxide through the openings 41 on the withdrawal side 43.

Extraction side 43 may operate under a combination of temperature and pressure at which carbon dioxide is a liquid. The supply side 42 may function at a first pressure, and the extraction side 43 may function at a second pressure, the second pressure is equal to or lower than the first pressure. The temperature on the extraction side 43 can be in the range from minus 55 to 0 ° C and can be higher than on the supply side 42. The holes 41 have an input size на42 on the supply side 42, which is larger than the output size Ό43 on the selection side 43. Output the size of может43 may be approximately equal to or substantially smaller than the grain size of the hardened carbon dioxide.

Although particular embodiments of the invention have been described above, it should be appreciated that the invention may be practiced in a manner other than that described. The description is intended to be illustrative and not restrictive. Accordingly, it will be apparent to those skilled in the art that modifications to the described embodiments of the invention can be made without departing from the scope of the claims presented below.

Claims (31)

CLAIM 1. A method of removing carbon dioxide from a fluid stream by means of a fluid separation device including a cyclone fluid separator (1) comprising a neck portion located between a tapering section for receiving a fluid and an expanding section for discharging a fluid, and an assembly to create vortices, made with the possibility of creating a vortex motion of a fluid containing carbon dioxide, inside at least part of the cyclone fluid separator, and the tapering section for iema fluid comprises a first inlet for fluid components and the expanding section of the fluid outlet comprises a first outlet for fluid depleted in carbon dioxide and a second outlet for the fluid rich in carbon dioxide; a separation tank (21) having a first section connected to the collection tank (23), wherein the first section is provided with a second inlet channel connected to said second outlet channel of the cyclone fluid separator, wherein the collection tank is provided with a third outlet channel for hardened carbon dioxide, In this case, the separation tank operates at a combination of pressure and temperature, which is located at or near the interface between the vapor / liquid / solid phase coexistence region for natural gas containing carbon dioxide (1U region 3a and in Fig 3.), and the coexistence region vapor / solid phase for natural gas containing carbon dioxide (area 1Ua Figure 3 a and 3.); wherein preparing a fluid stream into the inlet, the fluid stream comprising carbon dioxide; impart a swirling motion to the fluid flow in such a way as to stimulate the removal of at least one component from the condensed components and the cured components in the fluid flow in the lower flow of the assembly to create turbulences and to form an outgoing fluid flow; expanding the vortex fluid stream in such a way as to form liquefied carbon dioxide components in a metastable state in said fluid stream and stimulate the removal of said liquefied carbon dioxide components in a metastable state under the influence of vortex movement; extracting a fluid outlet stream containing the indicated components of liquefied carbon dioxide in a metastable state from the cyclone fluid separator through a second outlet channel; feeding the recovered fluid stream as a mixture to a separation tank through a second inlet; directing the specified mixture through the first section of the separation tank to the collection tank while ensuring the processing conditions in the first section so that the hardened carbon dioxide is formed from these components of the liquefied carbon dioxide in a metastable state; forming a layer of hardened carbon dioxide on the supply side (42) of the perforated screen (40) located in the collection tank (23) and containing holes (41) extended to the selection side (43); provide such temperature and pressure conditions on the withdrawal side (43) of the perforated screen (40) in order to separate the carbon dioxide from the layer by melting and to collect the molten carbon dioxide through the openings (41) on the withdrawal side (43). 2. The method according to claim 1, in which the side of the selection (43) operates with a combination of temperature and pressure, for which carbon dioxide is a liquid. 3. The method according to claim 2, in which the combination of temperature and pressure, for which carbon dioxide is a liquid, is selected from the range of 10-18 bar (1.0-1.8 MPa) and -55-0 ° C. 4. The method according to any one of claims 1 to 3, in which the supply side (42) operates at a first pressure, and the withdrawal side (43) operates at a second pressure, said second pressure being equal to or lower than the first pressure. 5. The method according to any one of the preceding paragraphs, in which the separation tank (21) operates at a pressure in the range of 5-25 bar (0.5-2.5 MPa) and a temperature range of (70-90) ° C. 6. The method according to any one of claims 1 to 5, in which the holes (41) have an input size (Ό42) on the supply side (42), which is larger than the output size (E43) on the selection side (43). 7. The method according to claim 6, in which the output size (E43) is equal to or less than the average grain size of the hardened carbon dioxide. 8. The method according to any one of the preceding paragraphs, in which the extracted fluid exit stream is supplied to the separation tank (21) tangentially to the perimeter of the first section (22), so that a rotational flow is formed in the first section (22). 9. The method according to any one of the preceding paragraphs, in which the first section (22) of the separation tank is also provided with a fifth exhaust channel (29), and the gaseous components depleted of carbon dioxide are recovered through the fifth exhaust channel (29). 10. The method according to claim 9, in which the fifth outlet channel is formed by a discharge nozzle containing a substantially vertical pipe elongated into the first section through the upper part of the first section in the lower direction, while the lower end of the pipe is lower in the vertical direction than second inlet channel. 11. The method according to any one of the preceding paragraphs, in which a conical turbulence damper (30) is placed between the first section and the collection tank (23). 12. The method according to any one of the preceding paragraphs, in which the collection tank is also provided with a fourth outlet channel (26), the hydrocarbon liquid components being recovered through the fourth outlet channel (26). 13. The method according to item 12, in which the hydrocarbon liquid components through the fourth exhaust channel (26) is returned to the cyclone fluid separator. 14. The method according to any one of the preceding paragraphs, in which the separation tank also comprises a cooling unit configured to provide predetermined temperature conditions therein, wherein the temperature conditions allow solidification of the carbon dioxide rich fluid. 15. The method according to any one of the preceding paragraphs, in which the fluid stream contains a molar concentration of carbon dioxide of more than 10%. 16. The method according to any one of the preceding paragraphs, in which the expansion of the vortex fluid flow is such that the vortex fluid flow reaches a supersonic speed. 17. The method according to clause 16, in which the expansion is also such that it reaches a temperature below 200 K. 18. The method according to clause 16 or 17, in which the expansion is also such that a pressure is achieved below 50% of the pressure in the first inlet channel of the cyclone fluid separator. 19. A fluid separation device that removes carbon dioxide from a fluid stream, including a cyclone fluid separator (1) comprising a neck portion (4) located between a tapering fluid receiving section and an expanding fluid discharge section and a swirl assembly configured to swirl a fluid containing carbon dioxide inside at least a portion of the separator, wherein the tapering fluid receiving section comprises a first an inlet for fluid components and an expanding section for discharging a fluid comprising: a first outlet for a carbon depleted fluid and a second outlet for a carbon enriched fluid; a separation tank (21) having a first section connected to the collection tank, the section being provided with a second inlet channel connected to the second outlet channel of the cyclone fluid separator, wherein the collection tank is provided with a third outlet channel (28) for hardened carbon dioxide, wherein The separation tank operates at a combination of pressure and temperature, which is at or near the interface between the vapor / liquid / solid phase coexistence region for natural gas, containing its carbon dioxide (1U region 3a and in Fig 3.), and the coexistence region of the steam / solid phase for natural gas containing carbon dioxide (area 1Ua Figure 3 a and 3.); - 11 020177 a perforated screen (40) having a supply side (42) and a withdrawal side (43), the supply side (42) being arranged so as to accumulate hardened carbon dioxide and form a layer of hardened carbon dioxide on the supply side (42), when this perforated screen is located in the collection tank (23) and contains holes (41), elongated to the side of the selection (42), while the specified device for separating a fluid made with the possibility of receiving a fluid stream containing carbon dioxide into the specified first inlet channel ; receiving the vortex movement of the fluid stream in such a way as to stimulate the removal of at least one component from the condensed components and the cured components in the fluid stream in the lower flow of the node to create turbulences and to form an outgoing fluid stream; expanding the vortex fluid stream in such a way as to form liquefied carbon dioxide components in a metastable state in said fluid stream and stimulate the removal of said liquefied carbon dioxide components in a metastable state under the influence of vortex movement; extracting a fluid outlet stream containing said metastable liquefied carbon dioxide components from a cyclone fluid separator through a second outlet; feeding the recovered fluid exit stream as a mixture to the separation tank through a second inlet; directing the specified mixture through the first section of the separation tank to the collection tank while ensuring the processing conditions in the first section so that the hardened carbon dioxide is formed from these components of the liquefied carbon dioxide in a metastable state; providing such temperature and pressure conditions on the withdrawal side (43) of the perforated screen (40) in order to separate the carbon dioxide from the layer by melting and collect the molten carbon dioxide through openings (41) on the withdrawal side (43). 20. A device for separating a fluid according to claim 19, also containing a temperature maintaining unit that maintains a suitable temperature on the withdrawal side (43) of the perforated screen (40), for fusing carbon dioxide in liquid form from the perforated screen (40). 21. A device for separating a fluid according to claim 19 or 20, in which the central element (11) has the largest external width 2K _max , which is greater than the smallest internal width 2K _{P t1P of the} tubular _neck portion (4). 22. A device for separating a fluid according to any one of paragraphs.19-21, in which the holes (41) have an input size (Ό42) on the supply side (42), which is larger than the output size (Ό43) on the selection side (43) . 23. The fluid separation apparatus of claim 22, wherein the output size (Ό43) is equal to or less than the average grain size of the hardened carbon dioxide. 24. A device for separating a fluid according to claim 22 or 23, in which the holes (41) are circular with a diameter on the selection side (43) in the range from 0.5 to 5 mm. 25. A fluid separation apparatus according to any one of claims 19-24, wherein the second inlet channel is a tangential inlet channel with respect to the perimeter of the first section, so that a rotational flow is generated in the first section (22). 26. A device for separating a fluid according to any one of paragraphs.19-25, in which the first section is also provided with a fifth outlet channel, configured to extract gaseous components depleted in carbon dioxide. 27. The fluid separation apparatus of claim 26, wherein the fifth outlet is formed by a discharge nozzle comprising a substantially vertical pipe extending into the first section through the upper portion of the first section in a lower direction, with the lower end of the pipe being lower vertical direction than the second inlet. 28. A fluid separation device according to any one of claims 19-27, wherein the conical turbulence damper (30) is located between the first section and the collection tank. 29. A device for separating a fluid according to any one of paragraphs.19-28, in which the collection tank is also equipped with a fourth outlet channel (26), configured to extract hydrocarbon liquid components. 30. A device for separating a fluid according to clause 29, containing a pipe (81) for feedback, and the pipe (81) for feedback is configured to return hydrocarbon liquid components from the fourth exhaust channel (26) to a cyclone fluid separator. 31. A device for separating a fluid according to any one of paragraphs.19-30, in which the separation tank also contains a cooling unit configured to provide specified temperature conditions, wherein the temperature conditions allow the solidification of the carbon dioxide-enriched fluid.