BACKGROUND

[0001] Embodiments of the present disclosure relate generally to systems and methods of recovering hydrocarbons, and more particularly to systems and methods of recovering hydrocarbons with supercritical CO2.

[0002] Supercritical CO2 is a fluid state of carbon dioxide where it is held at or above its critical temperature and critical pressure. Supercritical CO2 is becoming an important commercial and industrial solvent for oil extraction due to its good solubility with oil component in addition to its low toxicity and environmental impact. The relatively low temperature of the process and the stability of CO2 also allow most compounds to be extracted with little damage or denaturing.

[0003] In conventional methods for oil extraction with supercritical CO2, a mixture comprising the liquid CO2 and the extracted oil may be warm up to vaporize the liquid CO2, in order to separate the extracted oil. After the separation, the vaporized CO2 may be liquefied to produce liquid CO2. These repeated phase changes will consume a lot of energy. In addition, liquid CO2 may be pressurized in a preparation of the supercritical CO2, which also needs large amounts of energy. Therefore, high energy consumption has become one of the most serious issues in the conventional methods.

[0004] Therefore, it is desirable to provide new systems and methods of recovering hydrocarbons to solve the above-mentioned problems.

BRIEF DESCRIPTION

[0005] In one aspect, a system of recovering a hydrocarbon from an insoluble matrix comprises an extractor, a first separator, an expander and an energy transferring device. The extractor is configured to combine supercritical CO2 with a hydrocarbon-containing insoluble matrix material to form an extraction mixture. The first separator is configured to separate the extraction mixture into an extracted insoluble matrix material and an extract, wherein the extract comprises the supercritical CO2 and one or more hydrocarbons. The expander is configured to expand the extract to produce a C02-rich gaseous phase, a hydrocarbon-rich liquid phase and mechanical energy. The energy transferring device is coupled with the expander and configured to transfer at least a portion of the mechanical energy generated in the expander to a supercritical CO2 preparing device to produce supercritical CO2. [0006] In another aspect, a method of recovering a hydrocarbon from an insoluble matrix comprises combining supercritical CO2 with a hydrocarbon-containing insoluble matrix material to form an extraction mixture, and separating the extraction mixture into an extracted insoluble matrix material and an extract, wherein the extract comprises supercritical CO2 and one or more hydrocarbons. The extract is expanded to produce a CC -rich gaseous phase, a hydrocarbon-rich liquid phase, and mechanical energy. At least a portion of the mechanical energy generated in the expanding step is employed to produce supercritical CO2.

DRAWINGS

[0007] These and other features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:

[0008] Fig. 1 is a flowchart illustrating a method of recovering a hydrocarbon from an insoluble matrix in accordance with an exemplary embodiment of the present disclosure.

[0009] Fig. 2 is a flowchart illustrating a method of recovering a hydrocarbon from an insoluble matrix in accordance with another exemplary embodiment of the present disclosure.

[0010] Fig. 3 is a sketch view illustrating a system of recovering a hydrocarbon from an insoluble matrix in accordance with an exemplary embodiment of the present disclosure.

[0011] Fig. 4 is a sketch view illustrating a system of recovering a hydrocarbon from an insoluble matrix in accordance with another exemplary embodiment of the present disclosure.

[0012] Fig. 5 is a sketch view illustrating a system of recovering a hydrocarbon from an insoluble matrix in accordance with another exemplary embodiment of the present disclosure.

DETAILED DESCRIPTION

[0013] In an effort to provide a concise description of these embodiments, not all features of an actual implementation are described in one or more specific embodiments. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of the present disclosure. [0014] Unless defined otherwise, technical and scientific terms used herein have the same meaning as is commonly understood by one of ordinary skill in the art to which the present disclosure belongs. The terms "first," "second," "third," "fourth," and the like, as used herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. Also, the terms "a" and "an" do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced items. The term "or" is meant to be inclusive and mean either any, several, or all of the listed items. The use of "including," "comprising," or "having," and variations thereof herein are meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

[0015] Embodiments of the present disclosure refer to a system of recovering a hydrocarbon from an insoluble matrix with supercritical CO2, which can be widely applied in petroleum refining and petrochemical industries.

[0016] An exemplary system 3 of recovering a hydrocarbon from an insoluble matrix is illustrated in Fig.3. As shown in Fig. 3, the system 3 comprises an extractor 301, a first separator 303, an expander 305, a supercritical CO2 preparing device 313, an energy transferring device 311 coupled between the expander 305 and the supercritical CO2 preparing device 313.

[0017] The extractor 301 is configured to combine supercritical CO2 341 with a hydrocarbon- containing insoluble matrix material 342 to form an extraction mixture 343. The supercritical CO2 341 may come from the supercritical CO2 preparing device 313 or one or more supercritical CO2 sources which are not shown in the figure. The hydrocarbon-containing insoluble matrix material 342 may comprise an oil sand, a hydrocarbon-containing mud or a combination thereof. In some embodiments, the hydrocarbon-containing insoluble matrix material 342 may comprise an oil sand and an oil mud. The hydrocarbon-containing insoluble matrix material 342 may come from one or more feed devices capable of providing the hydrocarbon-containing insoluble matrix material.

[0018] The extraction mixture 343 formed by the extractor 301 flows to the first separator 303, which is configured to separate the extraction mixture 343 into an extracted insoluble matrix material 344 and an extract 345. The extracted insoluble matrix material 344 is substantially in a solid form and the extract 345 is substantially in a liquid form. Therefore, the first separator 303 may comprise a solid-liquid separator (not shown) for separating the extracted insoluble matrix material 344 from the extract 345. The extract 345 comprises supercritical CO2 and one or more hydrocarbons. [0019] The extract 345 from the first separator 303 is then transported to the expander 305, which is configured to expand the extract 345 to produce a CCh-rich gaseous phase 351, a hydrocarbon-rich liquid phase 352, and mechanical energy 353. The supercritical CCh in the extract 345 is vaporized to the CCh-rich gaseous phase in the expander 305, while the one or more hydrocarbons in the extract 345 remain in liquid. The system 3 may further comprise a second separator 307 for separating the hydrocarbon-rich liquid phase 352 from the CCh-rich gaseous phase 351. The hydrocarbon-rich liquid phase 352 flowing out of the second separator 307 may be further treated to obtain one or more hydrocarbons.

[0020] As used herein, the term "CCh-rich gaseous phase" refers to a gas comprising greater than 95 mole percentage of CCh relative to entire CCh-rich gaseous phase. The term "CCh-rich liquid phase" refers to a liquid comprising greater than 95 weight percentage of CCh relative to entire CCh-rich liquid phase. The term "hydrocarbon-rich liquid phase" refers to a liquid comprising greater than 95 weight percentage of hydrocarbons relative to entire hydrocarbon-rich liquid phase.

[0021] Referring again to Fig. 3, the energy transferring device 311 coupled between the expander 305 and the supercritical CCh preparing device 313 is configured to transfer at least a portion of the mechanical energy 353 to the supercritical CCh preparing device 313. The supercritical CCh preparing device 313 employs the at least a portion of mechanical energy 353 generated by the expander 305 to produce supercritical CCh, thus reducing external energy consumption. As such, the total energy consumption of the system 3 may be significantly reduced in compare with conventional systems in which the mechanical energy generated by the expander is wasted.

[0022] The supercritical CCh preparing device 313 is configured to produce supercritical CCh from a CCh-rich liquid phase. The CCh-rich liquid phase may come from a device which is a part of the system 3 and configured to produce the CCh-rich liquid phase, a source of CCh-rich liquid phase outside the system 3, or a combination thereof. As shown in the Fig.3, the CCh-rich liquid phase labeled as 354 comes from a second heat exchanger 309, which is configured to produce the CCh-rich liquid phase, and the CCh-rich liquid phase labeled as 355 flows from a source of CCh-rich liquid phase (not shown) outside the system 3.

[0023] The supercritical CCh preparing device 313 comprises at least one of a first pump 317 and a first heat exchanger 315. The first pump 317 is configured to pressurize the CCh-rich liquid phase, and the first heat exchanger 315 is configured to heat the CCh-rich liquid phase. In the embodiment shown in Fig.3, the supercritical CCh preparing device 313 comprises both of the first pump 317 and the first heat exchanger 315. In some embodiments, the CCh-rich liquid phase is firstly pressurized by the first pump 317 to a pressure in a range from about 7MPa to about 50MPa, and then heated by the first heat exchanger 315 to a temperature in a range from about 32 ^° C to about 100 ^° C to obtain the supercritical CCh.

[0024] In some embodiments, as shown in Fig.3, the energy transferring device 311 is coupled between the first pump 317 and the expander 305 for transferring the mechanical energy 353 to the first pump 317 directly. The energy transferring device 311 may comprise a shaft, a gear box or a combination thereof.

[0025] In some embodiments, the CCh-rich gaseous phase 351 flowing out of the second separator 307 may be recycled to the supercritical CCh preparing device 313 to produce the supercritical CCh. Therefore, the system 3 may further comprise at least one of a second heat exchanger 309 and a second pump (not shown). The at least one of the second heat exchanger 309 and the second pump are configured to liquefy at least a portion of the CC -rich gaseous phase 351 to a CCh-rich liquid phase 354, and then the CCh-rich liquid phase 354 is transported to the supercritical CCh preparing device 313 as a raw material for production of the supercritical CCh. Therefore, the system 3 may further comprise a first transporting device (not shown) for transporting the CCh-rich liquid phase 354 to the supercritical CCh preparing device 313 to produce the supercritical CCh. In some embodiments, the first transporting device may comprise a first pipe (not shown) coupled between the second heat exchanger 309 and the first pump 317 for transporting the CCh-rich liquid phase 354 to the first pump 317.

[0026] Fig. 4 shows another exemplary system 4 of recovering a hydrocarbon from an insoluble matrix of the present disclosure. Similar to the system 3 as shown in Fig.3, the system 4 comprises an extractor 401, a first separator 403, a first heat exchanger 415, a second separator 407, and a second heat exchanger 409, which are similar to the corresponding components of system 3 and description thereof will not be repeated here. The main difference is that, the expander 305, the first pump 317 and the energy transferring device 311 of the system 3 are integrated into a single pressure unit 421 in the system 4, thus reducing energy loss during transferring of the mechanical energy 353, and reducing a size of the system. The pressure unit 421 is capable of either increasing or decreasing a pressure of a material therein. When an extract 445 needs to be expanded, the pressure unit 421 may act as an expander to release a pressure of the extract 445 and generate the mechanical energy. When the CCh-rich liquid phase needs to be pressurized, the pressure unit 421 may act as a pump to treat the CCh-rich liquid phase. [0027] Referring to Fig. 4, a hydrocarbon-containing insoluble matrix material 442 is combined with supercritical CO2 441 by the extractor 401 to form an extraction mixture 443. The extraction mixture 443 is separated by the first separator 403 into an extracted insoluble matrix material 444 and the extract 445. The extract 445 is expanded by the pressure unit 421 to produce a CCh-rich gaseous phase 451, a hydrocarbon-rich liquid phase 452, and mechanical energy. At least a portion of the CCh-rich gaseous phase 451 is liquefied by the second heat exchanger 409 to produce a CCh-rich liquid phase 454. The CCh-rich liquid phase 454 is pressurized by the pressure unit 421 and then heated by the first heat exchanger 415 to produce supercritical CO2.

[0028] In some embodiments, referring to Fig.4, the system 4 further comprises a fourth heat exchanger 419 coupled between the first separator 403 and the pressure unit 421 for adjusting a temperature of the extract 445 before the extract 445 is expanded by the pressure unit 421.

[0029] In some embodiments, the system 4 further comprises a tank 423 coupled between the second heat exchanger 409 and the pressure unit 421 for storing the CCh-rich liquid phase 454 produced by the second heat exchanger 409. The tank 423 may be configured to further store a CCh-rich liquid phase 455 which comes from a source of CCh-rich liquid phase (not shown) outside the system 4.

[0030] Fig. 5 shows another exemplary system 5 of recovering a hydrocarbon from an insoluble matrix of the present disclosure. Similar to the system 3 which is shown in Fig.3, the system 5 comprises an extractor 501, a first separator 503, an expander 505, a supercritical CO2 preparing device 513, an energy transferring device 511, a second separator 507, and a second heat exchanger 509, wherein the supercritical CO2 preparing device 513 comprises a first heat exchanger 515 and a first pump 517. These components are similar to the corresponding components of system 3 and description thereof will not be repeated here. The main difference is that the system 5 further comprises a three-phase preparing device 525, configured to treat an extract 545 to obtain a three-phase mixture 546, wherein the three-phase mixture 546 comprises a CCh-rich liquid phase 547. At least a portion of the CCh-rich liquid phase 547 in the three-phase mixture 546 may be directly recycled to the supercritical CO2 preparing device 513 to produce the supercritical CCh, such that this portion of the CCh-rich liquid phase 547 does not need to be vaporized by the expander 505 and then liquefied by the second heat exchanger 509, thus reducing the energy consumption for phase change. Specifically, the CCh-rich liquid phase 547 is transported to the supercritical CCh preparing device 513 as a raw material for production of the supercritical CO2. Therefore, the system 5 may further comprise a second transporting device (not shown) for transporting the CCh-rich liquid phase 547 to the supercritical CO2 preparing device 513. In some embodiments, the second transporting device comprises a second pipe (not shown) configured to transport the CCh-rich liquid phase 547 to the first pump 517 of the supercritical CCh preparing device 513.

[0031] Referring to Fig.5, the three-phase preparing device 525 comprises at least one of a pressure regulator 527 and a third heat exchanger 529, wherein the pressure regulator 527 is configured to adjust a pressure of the extract 545, for example, to a range from about 4.5MPa to about 7.5MPa, and the third heat exchanger 529 is configured to adjust a temperature of the extract 545, for example, to a range from about 20 ^° C to about 32 ^° C . In the embodiment shown in Fig.5, the three-phase preparing device 525 comprises both of the pressure regulator 527 and the third heat exchanger 529 for treating the extract 545 to obtain the three-phase mixture 546.

[0032] Referring again to Fig. 5, a hydrocarbon-containing insoluble matrix material 542 is combined with supercritical CCh 541 by the extractor 501 to form an extraction mixture 543. The extraction mixture 543 is separated by the first separator 503 into an extracted insoluble matrix material 544 and the extract 545. The extract 545 is treated by the three-phase preparing device 525 to produce the three-phase mixture 546 comprising the CCh-rich liquid phase 547. At least a portion of the CCh-rich liquid phase 547 in the three-phase mixture 546 is transported to the first pump 517 to be pressurized. A remaining portion of the three-phase mixture 546 is expanded by the expander 505 to produce a CCh-rich gaseous phase 551, a hydrocarbon-rich liquid phase 552 and mechanical energy 553. At least of a portion of the mechanical energy 553 is transferred to the first pump 517 by the energy transferring device 511. At least a portion of the CCh-rich gaseous phase 551 is liquefied by the second heat exchanger 509 to produce a CCh-rich liquid phase 554. The CCh-rich liquid phase 554 is pressurized by the first pump 517 and then heated by the first heat exchanger 515 to produce supercritical CCh.

[0033] In some embodiments, the system 5 further comprises a liquid-liquid separator (not shown) for separating the at least a portion of the CCh-rich liquid phase 547 from the three-phase mixture 546.

[0034] In some embodiments, the system 5 further comprises a tank 523 coupled between the second heat exchanger 509 and the supercritical CCh preparing device 513 for storing the CCh- rich liquid phase 554 produced by the second heat exchanger 509. The tank 523 may be configured to further store a CCh-rich liquid phase 555 which comes from a source of CCh-rich liquid phase (not shown) outside the system 5.

[0035] Embodiments of the present disclosure also refer to a method of recovering a hydrocarbon from an insoluble matrix with supercritical CCh. While actions of the method are illustrated as functional blocks, the order of the blocks and the separation of the actions among the various blocks shown in Figs. 1 and 2 are not intended to be limiting. For example, the blocks may be performed in a different order and an action associated with one block may be combined with one or more other blocks or may be sub-divided into a number of blocks.

[0036] Fig. 1 is a flowchart of a method 1 of recovering a hydrocarbon from an insoluble matrix in accordance with an exemplary embodiment of the present disclosure. Referring to Fig. 1, the method 1 may comprise steps 11-15, which will be described in detail hereinafter.

[0037] At step 11, a hydrocarbon-containing insoluble matrix material is combined with supercritical CCh to form an extraction mixture. The supercritical CCh is used as a solvent for dissolving one or more hydrocarbons in the hydrocarbon-containing insoluble matrix material. In some embodiments, the hydrocarbon-containing insoluble matrix material may comprise an oil sand, a hydrocarbon-containing mud or a combination thereof. In some particular embodiments, the hydrocarbon-containing insoluble matrix material may comprise an oil sand and an oil mud.

[0038] At step 12, the extraction mixture is separated into an extracted insoluble matrix material and an extract, wherein the extract comprises supercritical CCh and one or more hydrocarbons. The step 12 may comprise a step of solid-liquid separation for separating the extracted insoluble matrix material from the extract, since the extracted insoluble matrix material is substantially in a solid form and the extract is substantially in a liquid form.

[0039] At step 13, the extract obtained in the step 12 is expanded to produce a CCh-rich gaseous phase, a hydrocarbon-rich liquid phase and mechanical energy. The supercritical CCh in the extract is gasified to CCh-rich gaseous phase because of pressure release, during which internal energy of the supercritical CCh is converted into the mechanical energy. The one or more hydrocarbons in the extract remain in liquid during the expanding. Therefore, the method may further comprise a step of gas-liquid separation for separating the CCh-rich gaseous phase from the hydrocarbon-rich liquid phase. Subsequently, the hydrocarbon-rich liquid phase may be treated to obtain one or more hydrocarbons. In some embodiments, a temperature of the extract is adjusted before the step 13 of expanding.

[0040] At step 14, at least a portion of the mechanical energy generated in the step 13 is employed to produce supercritical CCh. In some embodiments, at least a portion of the mechanical energy is recovered to compress the supercritical CCh, in order to reduce

consumption of external energy in the supercritical CCh compression process.

[0041] The supercritical CCh is produced from a CCh-rich liquid phase by at least one of pressurizing and heating the CCh-rich liquid phase. In some embodiments, the CCh-rich liquid phase is pressurized to a pressure in a range from about 7MPa to about 50MPa and then heated to a temperature in a range from about 32 ^° C to about 100 ^° Cto produce the supercritical CO2. The CCh-rich liquid phase may be pressurized with the mechanical energy generated in the step 13. The CCh-rich liquid phase may also be heated with the mechanical energy generated in the step 13.

[0042] At step 15, at least a portion of the CCh-rich gaseous phase obtained in the step 13 is liquefied to obtain a CCh-rich liquid phase, and then the CCh-rich liquid phase is recycled to, for example, a supercritical CCh preparing device as shown in Fig. 3, to produce the supercritical CO2. More specifically, the CCh-rich liquid phase is treated in the production of supercritical CO2. For example, the CCh-rich liquid phase may be pressurized to a pressure in the range from about 7MPa to about 50MPa and then heated to a temperature in the range from about 32 ^° C to about 100 ^° C .

[0043] In some embodiments, before the step 13 of expanding, the extract is treated to obtain a three-phase mixture comprising a CCh-rich liquid phase. At least a portion of the CCh-rich liquid phase in the three-phase mixture may be directly recycled to, for example, the supercritical CO2 preparing device as shown in the Fig. 3, to produce the supercritical CCh. Similar to the steps for producing the supercritical CO2 described above, the CCh-rich liquid phase may be pressurized and then heated in the production of supercritical CCh.

[0044] Fig. 2 shows another exemplary method 2 of recovering a hydrocarbon from an insoluble matrix in accordance with the embodiments as mentioned above, which comprises treating the extract to obtain a three-phase mixture, and recycling at least a portion of a CCh-rich liquid phase in the three-phase mixture. Similar to the method 1, the method 2 comprises combining supercritical CO2 with a hydrocarbon-containing insoluble matrix material to form an extraction mixture, and separating the extraction mixture into an extracted insoluble matrix material and an extract, which are respectively shown in step 21 and step 22.

[0045] At step 23, the extract is treated to obtain a three-phase mixture which comprises a CCh-rich liquid phase. In some embodiments, the three-phase mixture is obtained by adjusting a pressure of the extract to a range from about 4.5MPa to about 7.5MPa and adjusting a temperature of the extract to a range from about 20 ^° C to about 32 ^° C .

[0046] At step 24, at least a portion of the CCh-rich liquid phase is separated from the three- phase mixture. Thus, the step 24 may comprise a step of liquid-liquid separation for separating the at least a portion of the CCh-rich liquid phase from the three-phase mixture. The at least a portion of the CCh-rich liquid phase is then treated in the production of supercritical CO2 as illustrated in step 25. For example, the CCh-rich liquid phase is pressurized or heated to produce the supercritical CO2. In another example, the CCh-rich liquid phase is pressurized and then heated to produce the supercritical CO2.

[0047] At step 26, a remaining portion of the three-phase mixture is expanded to produce a CCh-rich gaseous phase, a hydrocarbon-rich liquid phase and mechanical energy. Subsequently, at least a portion of the mechanical energy is employed to produce supercritical CO2, as illustrated in step 27. Specifically, the mechanical energy is employed to compress supercritical CO2. After the step 27, the process may be repeated from step 21, and the produced supercritical CO2 may be used to combine with the hydrocarbon-containing insoluble matrix material in step 21.

[0048] As will be understood by those familiar with the art, the present disclosure may be embodied in other specific forms without depending from the spirit or essential characteristics thereof. Accordingly, the disclosures and descriptions herein are intended to be illustrative, but not limiting, of the scope of the disclosure which is set forth in the following claims.