Methods and systems for separating compounds

Abstract

A method and system for separating sublimable compounds from hydrocarbons are disclosed. A feed fluid stream consisting of hydrocarbons and sublimable compounds is introduced into the upper chamber of a vessel. The feed fluid stream is cooled in the upper chamber, causing a portion of the sublimable compounds in the feed liquid stream to sublimate to form a product gas stream and a sublimable compound snow-like substance, the latter of which is collected in the lower chamber of the vessel. The lower portion of the sublimable compound snow-like substance is melted to form a liquid sublimable compound stream, such that the upper portion of the solid sublimable compound snow-like substance remains as an insulating barrier between the upper chamber and the liquid sublimable compound stream. The sublimable compound stream is removed from the ore liquid at a rate matching the rate of formation of the solid sublimable compound snow-like substance, thereby maintaining the insulating barrier.

Description

[0001] Priority requirements

[0002] This application claims priority to U.S. Patent Application No. 16 / 834,927, filed March 30, 2020, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] The methods and processes described in this article generally involve fluid separation. Background Technology

[0004] Fluid component separation is typically energy-intensive or complex. Separating components is possible, but higher purity requirements usually necessitate more unit operations. Alternatives to traditional fluid separation techniques are needed. Summary of the Invention

[0005] In a first aspect, this disclosure provides a method for continuously separating a sublimable compound from a hydrocarbon. A container having an upper chamber and a lower chamber is provided. A feed fluid stream is introduced into the upper chamber. The feed fluid stream consists of a hydrocarbon and a sublimable compound. The feed fluid stream is cooled in the upper chamber, causing a portion of the sublimable compound to sublimate from the feed fluid stream, forming a solid sublimable compound snow and a product gas stream. The solid sublimable compound snow is collected in the lower chamber. The lower portion of the solid sublimable compound snow is melted to form a liquid sublimable compound stream, while the upper portion of the solid sublimable compound snow remains as an insulating barrier between the upper chamber and the liquid sublimable compound stream. The liquid sublimable compound stream is removed at a rate matching the rate of solid sublimable compound snow formation, thereby maintaining the insulating barrier. The product gas stream is removed from the upper chamber.

[0006] In a second aspect, this disclosure provides a method for continuously separating components. A container having an upper chamber and a lower chamber is provided. A feed fluid stream, consisting of methane and carbon dioxide, is introduced into the upper chamber. A cold liquid stream, consisting of methane, is flash-electrode into the upper chamber to lower its temperature. Carbon dioxide is sublimated from the feed fluid stream to form a solid carbon dioxide flake and a product gas stream. The solid carbon dioxide flake is collected in the lower chamber. The lower portion of the solid carbon dioxide flake is melted to form a liquid carbon dioxide stream, while the upper portion of the solid carbon dioxide flake remains as an insulating barrier between the upper chamber and the liquid carbon dioxide stream. The liquid carbon dioxide stream is removed at a rate matching the rate of solid carbon dioxide flake formation, thereby maintaining the insulating barrier. The product gas stream is removed from the upper chamber.

[0007] In a third aspect, this disclosure provides a system for the continuous separation of components. The container comprises an upper chamber and a lower chamber. The upper chamber comprises a feed gas inlet, a cooling source, and a product gas outlet. The lower chamber comprises a product liquid outlet and a heat source. The feed gas inlet is configured to allow a feed gas stream to enter the upper chamber. The feed gas stream consists of hydrocarbons and sublimable compounds. The cooling source cools the feed gas stream, causing a portion of the sublimable compounds to sublimate from the feed gas stream, forming a solid sublimable snow-like substance and the product gas stream. The solid sublimable compound snow-like substance falls into the lower chamber. The heat source melts the lower portion of the solid sublimable compound snow-like substance in the lower chamber to form a liquid sublimable compound stream, while the upper portion of the solid sublimable compound snow-like substance remains as an insulating barrier between the upper chamber and the liquid sublimable compound stream. The product liquid outlet is configured to remove the liquid sublimable compound stream at a rate matching the rate of solid sublimable compound snow formation, thereby maintaining the insulation barrier. The product gas outlet is configured to remove the product gas stream from the upper chamber.

[0008] Other aspects and embodiments are provided in the foregoing drawings, detailed descriptions and claims. Attached Figure Description

[0009] The following figures are provided to illustrate certain embodiments described herein. The figures are merely illustrative and are not intended to limit the scope of the claimed invention, nor are they intended to show every potential feature or embodiment of the claimed invention. The figures are not necessarily drawn to scale: in some cases, certain elements of the figures may be enlarged relative to other elements for illustrative purposes.

[0010] Figure 1 This is a flowchart showing a method for separating compounds.

[0011] Figure 2 This is a flowchart showing a method for separating compounds.

[0012] Figure 3 This is a flowchart showing a method for separating compounds.

[0013] Figure 4 It is an isometric sectional view showing the system used to separate compounds. Detailed Implementation

[0014] The following description illustrates various aspects and embodiments of the invention disclosed herein. No specific embodiments are intended to define the scope of the invention. Rather, the embodiments provide non-limiting examples of various compositions and methods that are included within the scope of the claimed invention. This specification is intended to be read by one of ordinary skill in the art. Therefore, information well-known to one of ordinary skill is not necessarily included.

[0015] definition

[0016] Unless otherwise provided herein, the following terms and phrases have the meanings indicated below. Other terms and phrases not expressly defined herein may be used in this disclosure. These other terms and phrases should be understood to have the meanings that a person skilled in the art would have in the context of this disclosure. In some cases, a term or phrase may be defined in either a singular or plural form. In such cases, it should be understood that any singular term may include its plural counterpart, and vice versa, unless the contrary is explicitly stated.

[0017] As used herein, the singular forms “a,” “an,” “the,” and “the” include plural referents unless the context clearly indicates otherwise. For example, references to “substitute” include a single substitute as well as two or more substitutes, etc.

[0018] As used herein, "for example," "such as," "like," or "including," "comprising," "containing," or "having" are intended to describe embodiments that further illustrate a more general subject matter. Unless otherwise expressly stated, these examples are provided merely to aid in understanding the embodiments shown in this disclosure and are not intended to be limiting in any way. These phrases also do not imply any type of preference for the disclosed embodiments.

[0019] As used in this article, "Cl" refers to methyl ...

[0020] As used in this article, "natural gas" refers to a gas that mainly contains methane and may also contain other components such as ethane, propane, butane, water, and carbon dioxide.

[0021] As used herein, "sublimate" refers to a compound that undergoes a direct phase transition from gas to solid. "Sublimable" means that the compound is capable of sublimation under pressure and temperature conditions within a container. In a preferred embodiment, "sublimable compound" includes carbon dioxide, sulfur oxides, nitrogen oxides, carbon monoxide, and combinations thereof.

[0022] The separation of components is often complicated by the presence of miscible or similarly boiling components. For example, propane has a certain solubility in water, and heptane has a boiling point almost identical to that of water. Hydrocarbon streams contaminated with carbon dioxide and water further increase the overall complexity. This invention discloses a method and system for separating sublimable compounds, such as carbon dioxide, from hydrocarbons such as natural gas. In one embodiment of the invention, a feed liquid or gas containing hydrocarbons and sublimable compounds is introduced into the upper chamber of a container. If the feed stream is liquid, it is passed into the upper chamber to flash into a gas. A second stream, primarily composed of hydrocarbons, is flashed into the container. The flashing of one or both streams cools the upper chamber, causing the sublimable compounds to cool and directly sublimate into a solid snow-like substance. This solid snow-like substance is collected in the lower chamber of the container, where it is melted. Melting occurs at the bottom of the lower chamber by means of a heating element or by the reinjection of a heated liquid sublimable compound stream. The solid snow-like material is melted at a rate that keeps the upper part of the material solid, providing an insulating barrier between the upper chamber and the resulting liquid. Furthermore, the liquid is removed at a rate that maintains the insulating barrier. Gases formed in the upper chamber are also removed from the container. This process allows compounds such as carbon dioxide to be removed from hydrocarbons such as natural gas in a single container. This eliminates any solids handling issues. Moreover, as the compound snow-like material descends and melts from the solid to the liquid, any hydrocarbons trapped in the snow-like material's void spaces are expelled as the void spaces collapse, thus driving the hydrocarbons out of the resulting liquid and upwards into the upper chamber, improving separation purity.

[0023] Now refer to Figure 1 , Figure 1 This is a flowchart illustrating a method for separating compounds that can be used in one embodiment of the present invention. Container 100 consists of an upper chamber 10 and a lower chamber 12. An induction heater 14 is installed in the lower part of the lower chamber 12. The upper chamber is maintained at a pressure of 6 bar. The feed fluid stream 30 is a natural gas stream and contains at least 20 wt% carbon dioxide. The feed fluid stream 30 is at a pressure of at least 25 bar and a temperature below -55°C. The cold liquid stream 38 is a natural gas stream containing no more than 3 wt% carbon dioxide, at a pressure of 50 bar and a temperature below -102°C. In other words, the cold liquid stream 38 meets the standards for pipeline natural gas delivery. The feed fluid stream 30 is introduced into the upper chamber 10, where any liquid present in the feed fluid stream 30 is flashed into vapor. Simultaneously, the cold liquid stream 38 is flashed into the upper chamber 10, generating further vapor. Vaporization requires heat absorbed from the vapor and causes carbon dioxide to sublimate to form solid carbon dioxide snow 31 in the upper chamber 10. The solid carbon dioxide snow-like substance 31 falls from the upper chamber 10 into the top 33 of the lower chamber 12.

[0024] Induction heater 14 heats the lower portion 35 of the lower chamber 12. This causes the solid carbon dioxide atomized material in the lower portion 35 to melt, forming a liquid carbon dioxide stream 34. Sufficiently low heat is maintained so that only the lower portion 35 melts, while the solid carbon dioxide atomized material deposited in the upper portion 33 remains as an insulating barrier between the upper chamber 10 and the liquid carbon dioxide stream. The term "insulating" firstly means that heat does not propagate back to the upper chamber 10, and secondly, that the vapor in the upper chamber 10 is physically separated from the liquid carbon dioxide stream 34, preventing the liquid from evaporating back into the vapor. The liquid carbon dioxide stream 34 is removed at a rate matching the rate of solid carbon dioxide atomized material 31 production, maintaining the insulating barrier in the upper portion 33.

[0025] Uncondensed vapor exits the upper chamber 10 as product gas stream 32. A portion of the product gas stream 36 is passed through the refrigeration circuit 16, where it is pressurized and cooled to produce a cold liquid stream 38. The remaining product gas stream 40 is a product stream that can be further processed to remove residual carbon dioxide, or it can be used as a product gas stream for natural gas without further processing.

[0026] In this embodiment, if the surface area surrounding the lower portion 35 is large enough, an induction heater 14 is not necessary. Simply removing any insulating layer from the lower portion of the lower chamber 12 would provide sufficient heat from the ambient air to melt the solid carbon dioxide snow.

[0027] Now refer to Figure 2 , Figure 2 This is a flowchart illustrating a method for separating compounds that can be used in one embodiment of the present invention. The container 200 consists of an upper chamber 10 and a lower chamber 12. The upper chamber includes an indirect contact heat exchanger 15 equipped with a vibrator. A feed gas stream 30, consisting of a sublimable compound and hydrocarbons, is introduced into the upper chamber 10. The sublimable compound sublimes onto the heat exchanger 15, causing the heat exchanger 15 to vibrate so that solids are shed as solid sublimable compound snowflakes 31, which fall from the upper chamber 10 into the top 33 of the lower chamber 12.

[0028] A warm liquid stream 42, consisting of sublimable compounds, is pumped into the lower section 35 of the lower segment 12, melting the solid sublimable compound snow-like material in the lower section 35 to form a liquid sublimable compound stream 34. The temperature and flow rate of the warm liquid stream 42 are kept sufficiently low to melt only the lower section 35, while the solid sublimable compound snow-like material deposited in the upper section 33 is retained as an insulating barrier between the upper chamber 10 and the liquid sublimable compound stream. The term "insulation" means that heat is not propagated back to the upper chamber 10, and the vapor in the upper chamber 10 is physically separated from the liquid sublimable compound stream 34, preventing the liquid from evaporating back into vapor. The liquid sublimable compound stream 34 is removed at a rate matching the rate of formation of the solid sublimable compound snow-like material 31, maintaining the insulating barrier in the upper section 33.

[0029] Uncondensed vapor exits the upper chamber 10 as product gas stream 32. A portion of the product gas stream 36 is passed through the refrigeration circuit 16, where it is pressurized and cooled to produce a cold liquid stream 38. The remaining product gas stream 40 is the product stream.

[0030] Now refer to Figure 3 , Figure 3 This is a flowchart illustrating a method for separating compounds that can be used in one embodiment of the present invention. The container 300 consists of an upper chamber 10 and a lower chamber 12. A screw conveyor 18 is installed in the lower chamber 12. A feed fluid stream 30, consisting of a sublimable compound and hydrocarbons, is introduced into the upper chamber 10, where any liquid present in the feed fluid stream 30 is flashed into vapor. Simultaneously, a cold liquid stream 38 is flashed into the upper chamber 10, generating further vapor. Evaporation requires heat absorbed from the vapor and causes the sublimable compound to sublimate, forming a solid sublimable compound snowflake 31 in the upper chamber 10. This solid sublimable compound snowflake 31 falls from the upper chamber 10 into the top 33 of the lower chamber 12.

[0031] A warm liquid stream 42, consisting of a sublimable compound, is pumped into the lower section 35 of the lower section 12, melting the solid sublimable compound snow-like material in the lower section 35 to form a liquid sublimable compound stream 34. The temperature and flow rate of the warm liquid stream 42 are kept sufficiently low to melt only the lower section 35 while allowing the solid sublimable compound snow-like material to deposit in the upper section 33, acting as an insulating barrier between the upper chamber 10 and the liquid sublimable compound stream. The term "insulating" means firstly that heat is not propagated back to the upper chamber 10, and secondly that the vapor in the upper chamber 10 is physically separated from the liquid sublimable compound stream 34, preventing the liquid from evaporating back into the vapor. The liquid sublimable compound stream 34 is removed at a rate matching the rate at which the solid sublimable compound snow-like material 31 is produced, maintaining the insulating barrier in the upper section 33. The solid sublimable compound is transported from the upper section 33 to the lower section 35 via a screw conveyor 18.

[0032] Uncondensed vapor exits the upper chamber 10 as product gas stream 32. A portion of the product gas stream 36 is passed through the refrigeration circuit 16, where it is pressurized and cooled to produce a cold liquid stream 38.

[0033] Now refer to Figure 4 , Figure 4 This is an isometric sectional view showing a system for separating compounds that can be used in one embodiment of the present invention. The container 400 consists of an upper chamber 10 and a lower chamber 12. The upper chamber has a feed gas inlet, a cooling source, and a product gas outlet. The lower chamber has a product liquid outlet and a heat source 14.

[0034] The feed fluid inlet is configured to allow the feed gas stream to enter the upper chamber. The feed fluid stream consists of hydrocarbons and sublimable compounds. A cooling source cools the feed fluid stream. In this embodiment, the cooling source is a cold liquid stream flashed into the upper chamber 10. Vaporization requires heat absorbed from the feed fluid stream and causes the sublimable compounds to sublimate, forming a snow-like substance of solid sublimable compounds and a product gas stream in the upper chamber 10. The solid sublimable compound snow-like substance falls into the lower chamber 12, forming an insulating barrier 33.

[0035] In this embodiment, the heat source 14 is a set of heating coils wound around the lower portion 35 of the lower chamber 12. The heat source 14 melts the lower portion of the solid sublimable compound snow in the lower chamber to form a liquid sublimable compound stream, while the upper portion of the solid sublimable compound snow remains as an insulating barrier between the upper chamber and the liquid sublimable compound stream. The product liquid outlet is configured to remove the liquid sublimable compound stream at a rate matching the generation rate of the solid sublimable compound snow, thereby maintaining the insulating barrier. The product gas outlet is configured to remove the product gas stream from the upper chamber.

[0036] In some embodiments, solids may form bridging when assembled as insulating barrier 33. Heating walls are not always necessary, but in some embodiments, heating will prevent bridging and create a suitable insulating barrier 33.

[0037] In some embodiments, the sublimable compound is selected from carbon dioxide, sulfur oxides, nitrogen oxides, carbon monoxide, and combinations thereof. In some embodiments, the hydrocarbon is selected from methane, ethane, propane, and combinations thereof.

[0038] The present invention has been described with reference to various specific and preferred embodiments and techniques. However, it should be understood that many changes and modifications can be made while remaining within the spirit and scope of the invention.

Claims

1. A method for the continuous separation of sublimable compounds from hydrocarbons, comprising: Provides a container comprising an upper chamber and a lower chamber; A feed fluid stream is introduced into the upper chamber, the feed fluid stream containing hydrocarbons and sublimable compounds; The feed fluid stream is cooled in the upper chamber, thereby causing a portion of the sublimable compound to sublimate from the feed fluid stream to form a solid sublimable compound snow-like substance and a product gas stream. The solid sublimable compound snow-like substance is collected in the lower chamber; The lower part of the solid sublimable compound snow-like material is melted to form a liquid sublimable compound stream, such that the upper part of the solid sublimable compound snow-like material remains as an insulating barrier between the upper chamber and the liquid sublimable compound stream. The liquid sublimable compound stream is removed at a rate matching the rate of formation of the solid sublimable compound snow, thereby maintaining the insulating barrier; and The product gas stream is removed from the upper chamber.

2. The method of claim 1, wherein the sublimable compound is selected from carbon dioxide, sulfur oxides, nitrogen oxides, carbon monoxide, and combinations thereof.

3. The method of claim 1, wherein the hydrocarbon is selected from methane, ethane, propane, and combinations thereof.

4. The method of claim 1, wherein cooling the feed fluid stream comprises flashing a cold liquid stream into the upper chamber to reduce the temperature of the upper chamber, the cold liquid stream comprising hydrocarbons.

5. The method of claim 4, further comprising passing a portion of the product gas stream through a refrigeration circuit to generate the cold liquid stream.

6. The method of claim 1, wherein melting comprises injecting a warm liquid sublimable compound stream into the lower chamber.

7. The method of claim 1, wherein melting includes heating the lower chamber with a heating element.

8. A method for continuous separation of components, comprising: Provides a container comprising an upper chamber and a lower chamber; A feed fluid stream containing methane and carbon dioxide is introduced into the upper chamber; A cold liquid stream is flashed into the upper chamber to reduce the temperature of the upper chamber, wherein the cold liquid stream contains methane; The carbon dioxide in the feed fluid stream is sublimated to form solid carbon dioxide snow and a product gas stream; The solid carbon dioxide snow-like substance is collected in the lower chamber; The lower part of the solid carbon dioxide snow-like substance is melted to form a liquid carbon dioxide stream, while the upper part of the solid carbon dioxide snow-like substance remains as an insulating barrier between the upper chamber and the liquid carbon dioxide stream. The liquid carbon dioxide stream is removed at a rate matching the rate of generation of the solid carbon dioxide snow, thereby maintaining the insulating barrier; and The product gas stream is removed from the upper chamber.

9. The method of claim 8, wherein the feed fluid stream comprises at least 20 wt% carbon dioxide, at least 25 bar, and below -55°C.

10. The method of claim 8, wherein the feed fluid stream comprises a C2+ natural gas component.

11. The method of claim 8, wherein the cold liquid stream comprises no more than 3 wt% carbon dioxide, at least 50 bar, and below -102°C.

12. The method of claim 8, further comprising passing a portion of the product gas stream through a refrigeration circuit to generate the cold liquid stream.

13. The method of claim 8, wherein melting comprises injecting a warm liquid carbon dioxide stream into the lower chamber.

14. The method of claim 8, wherein melting includes heating the lower chamber with a heating element.

15. A system for continuous separation of components, comprising: A container comprising an upper chamber and a lower chamber; The upper chamber includes a feed gas inlet, a cooling source, and a product gas outlet; The lower chamber includes a product liquid outlet and a heat source; The feed gas inlet is configured to allow a feed gas stream to enter the upper chamber through the feed gas inlet, the feed gas stream comprising hydrocarbons and sublimable compounds; The cooling source cools the feed gas stream, causing a portion of the sublimable compound to sublimate from the feed gas stream to form solid sublimable snow-like material and product gas stream, the solid sublimable compound snow-like material falling into the lower chamber; The heat source melts the lower part of the solid sublimable compound snow-like material in the lower chamber to form a liquid sublimable compound stream, while the upper part of the solid sublimable compound snow-like material remains as an insulating barrier between the upper chamber and the liquid sublimable compound stream. The product liquid outlet is configured to remove the liquid sublimable compound stream at a rate matching the rate of generation of the solid sublimable compound snow, thereby maintaining the insulating barrier; and The product gas outlet is configured to remove the product gas stream from the upper chamber.

16. The system of claim 15, further comprising a refrigerant circuit configured to receive, cool, and compress a portion of the product gas stream to form a cold liquid stream, wherein the cooling source is a result of flashing the cold liquid stream into the upper chamber.

17. The system of claim 15, wherein the heat source is an inductive resistor heater embedded in or attached to the wall of the lower chamber.

18. The system of claim 15, wherein the heat source is an indirect contact heat exchanger.

19. The system of claim 15, wherein the lower chamber includes a helical conveyor configured to deliver the solid sublimable compound snow toward the product liquid outlet as the solid sublimable compound snow melts.

20. The system of claim 15, wherein the sublimable compound is selected from carbon dioxide, sulfur oxides, nitrogen oxides, carbon monoxide, and combinations thereof.

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