Gas-liquid separation device for ebullated bed reactors

Abstract

A gas-liquid separator adapted to separate liquids and gases in an ebullated bed reactor under operating conditions is disclosed. The device can be used in the petroleum and chemical processing industries to separate gases and liquids from a gas-liquid mixture in the reactor during catalytic reactions of hydrocarbonaceous feedstocks at high temperatures and pressures in the presence of hydrogen. The device can be oriented generally vertically and installed in the flow-through pan of the ebullated bed reactor. The device includes a transfer conduit for transferring a gas-liquid mixture from a lower section of the ebullated bed reactor to an upper section of the reactor, a vortex separator having outlets for a gas-rich stream and a liquid-rich stream, and a gas-rich outlet conduit located adjacent to the top of the vortex separator. The transfer conduit includes an internal means for generating helical flow in the gas-liquid mixture, such as a helical insert or spiral insert. The vortex separator is located at the top of the transfer conduit and includes separation means for separating the gas-liquid mixture into a liquid-rich stream and a gas-rich stream. The separation means may be a separator conduit extending from the top of the vortex separator to the upper opening of the transfer conduit, aligned with the gas-rich outlet, and having substantially the same cross-sectional dimensions as that outlet. Advantages provided include improved efficiency of gas-liquid separation and reduced gas holdup within the reactor.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 426,031, entitled "GAS-LIQUID SEPARATION DEVICE FOR AN EBULLATED BED REACTOR," filed November 16, 2022, the disclosure of which is incorporated herein by reference in its entirety.

[0002] A gas-liquid separator for an ebullated bed hydroprocessing reactor is disclosed that can be used in the petroleum and chemical processing industries to separate gases and liquids from a gas-liquid mixture during catalytic reactions of hydrocarbonaceous feedstocks in the presence of hydrogen at high temperatures and pressures. [Background technology]

[0003] The ebullated bed (EB) reactor hydrogenation process involves passing a simultaneous flowing liquid stream or a slurry of liquid, solids, and gas through a vertical cylindrical vessel containing a catalyst. The catalyst is disposed in a random motion within the liquid, and the total volume dispersed in the liquid medium is greater than the volume of the mass at rest. EB technology has commercial applications in upgrading heavy liquid hydrocarbons or converting coal to synthetic oils. The process is generally described in U.S. Patent No. 25,770 to Johanson. Several other patent publications, such as U.S. Patent Nos. 4,221,653, 4,151,073, 4,354,852, 3,668,116, 4,012,314, 4,886,644, 5,066,467, 5,624,642, and 7,060,228, describe EB reactors and processes, as well as useful improvements. Generally, the mixture of hydrocarbon liquid and hydrogen is passed upward through the catalyst particle bed at a velocity such that the particles are put into random motion as the liquid and gas pass upward through the bed. The motion of the catalyst bed is controlled by the flow of circulating liquid so that, under steady state conditions, the majority of the catalyst does not exceed a specified level in the reactor. The vapor, along with the liquid, passes through the upper layer of the catalyst particles into a substantially catalyst-free zone and is removed at the top of the reactor.

[0004] During operation, substantial amounts of hydrogen gas and light hydrocarbon vapors present in the ebullated bed rise through the reaction zone into a catalyst-free zone. From this zone, liquid is recycled to the bottom of the reactor as product and removed from the reactor. The vapor is separated from the liquid circulation stream and travels through a circulation conduit to the circulation pump suction. The circulation pump (ebullation pump) maintains the expansion (boiling) and random motion of the catalyst particles at a constant, steady level. The presence of gas or vapor in the recycled liquid not only substantially reduces the capacity of the circulation pump, but also reduces the residence time of the liquid in the reactor, limiting the hydrogen partial pressure.

[0005] Reactors used in catalytic hydrogenation processes employing ebullated beds of catalyst particles are designed with a central vertical circulation downcomer that circulates liquid from a catalyst-free zone above the ebullated catalyst bed to the suction of a circulation pump for recirculation through the catalytic reaction zone. The circulation of liquid from the top of the reactor serves to boil the catalyst bed, maintain temperature uniformity throughout the reactor, and stabilize the catalyst bed.

[0006] The EB reactor process can present several operational technical challenges. For example, if hydrogen and other gases are not substantially removed from the liquid recycle stream via the recycle pump, the recycle gases can reduce conversion by occupying reactor volume that would otherwise be occupied by the liquid feed. Therefore, hydrogen and other gases must be separated from the recycle liquid before being reintroduced into the three-phase gas / liquid / catalyst reaction zone. Because the catalyst in the three-phase zone is primarily boiled by the upward flow of the liquid, a recycle stream with a high gas content will reduce the liquid velocity in the three-phase zone. As a result, the recycle pump must operate at a higher rotational speed to maintain a constant expanded catalyst bed height. When the pump speed reaches its maximum, the upward flow of liquid may not be strong enough to suspend the catalyst, causing it to settle onto the support grid. This can lead to hot spots in the settled catalyst bed, which can pose safety concerns.

[0007] Therefore, there is a continuing need for improvements in the operation and design of ebullated bed reactors, including improvements in gas-liquid separation in ebullated bed reactors. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] U.S. Patent No. 25,770 [Patent Document 2] U.S. Patent No. 4,221,653 [Patent Document 3] U.S. Patent No. 4,151,073 [Patent Document 4] U.S. Patent No. 4,354,852 [Patent Document 5] U.S. Patent No. 3,668,116 [Patent Document 6] U.S. Patent No. 4,012,314 [Patent Document 7] U.S. Patent No. 4,886,644 [Patent Document 8] U.S. Patent No. 5,066,467 [Patent Document 9] U.S. Patent No. 5,624,642 [Patent Document 10] U.S. Patent No. 7,060,228 Summary of the Invention

[0009] The present invention is directed to a gas-liquid separation device (also referred to herein as a "separator") adapted to separate gas and liquid in an ebullated bed reactor under operating conditions. The device, when installed in the flow-through pan of the ebullated bed reactor, effectively separates gas and liquid from a gas-liquid mixture. The device effectively separates gas and liquid while minimizing gas holdup within the reactor. The device is well suited for retrofit applications and can be used in new reactor designs to achieve efficient gas-liquid separation, resulting in improved operational performance of the ebullated bed reactor. Benefits provided include improved efficiency of gas-liquid separation and reduced gas holdup within the reactor. While generally intended for use in ebullated bed reactors, the device can also be used in other petroleum refining and chemical processing operations.

[0010] The gas-liquid separator device is oriented substantially vertically within the reactor and is typically installed in the flow-through (circulation) pan of an ebullated bed reactor. The device includes a transfer conduit for transferring a gas-liquid mixed stream from the lower section of the ebullated bed reactor to the upper section of the reactor, a vortex separator having outlets for a gas-rich stream and a liquid-rich stream and an upper plate, and a gas-rich outlet conduit located adjacent to the top of the vortex separator. The transfer conduit includes an internal means for generating a helical flow in the gas-liquid mixture, such as a helical insert or a spiral insert. The vortex separator is located at the top of the transfer conduit and includes a separation means for separating the gas-liquid mixed stream into a liquid-rich stream and a gas-rich stream. The separation means may be a separator conduit extending from the top of the vortex separator to the upper opening of the transfer conduit, aligned with the gas-rich outlet, and having substantially the same cross-sectional dimensions as the outlet.

[0011] The present invention also relates to a process for separating gas and liquid in a gas-liquid mixture. The process generally involves passing a gas-liquid mixture vertically through a conduit having an internal means for inducing a vertical helical flow in the gas-liquid mixture flowing through the conduit. The helical flow gas-liquid mixture is then fed into a vortex separator so that the helical flow gas-liquid mixture contacts a separation conduit. The separation conduit is aligned along its length substantially parallel to the vertical flow path of the helical flow gas-liquid mixture. The helical flow of the mixture causes liquid to be primarily located outside the helical flow path, while the interior of the helix is ​​primarily gas. The separation conduit separates a liquid-rich stream flowing outside the separation conduit from a gas-rich stream flowing inside the separation conduit. The liquid-rich stream is then directed to a liquid-rich outlet, and the gas-rich stream is directed to a separate gas-rich outlet.

[0012] 1-3 provide representative diagrams of a gas-liquid separation device and installation within an ebullated bed reactor according to embodiments of the present invention. It should be understood that the scope of the present invention is not limited by these representative diagrams, but is defined by the appended claims. [Brief explanation of the drawings]

[0013] [Figure 1]1 shows a vertical cross section of a separation device of the present invention. [Figure 2] 1 shows an isometric side view of a separation device of the present invention. [Figure 3] 1 shows the top of an ebullated bed reactor with multiple separation devices installed in a flow-through (circulation) pan according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] Certain embodiments and advantages are apparent from the detailed description provided herein. However, it should be understood that the detailed description, drawings, and any specific examples, including some preferred embodiments, are intended for illustrative purposes only and are not intended to limit the scope of the invention.

[0015] The present invention is generally directed to a separation device ("separator") for separating gas and liquid from a gas-liquid mixture. The separator is particularly adapted for use in hydroprocessing reactors, particularly ebullated bed reactors. When installed in the flow-through (circulation) pan of an ebullated bed reactor, the device effectively separates gas and liquid from the gas-liquid mixture while minimizing gas holdup within the reactor.

[0016] The separator includes a transfer conduit, a vortex separator (having a separation conduit located therein and gas and liquid outlets), and a gas conduit for flowing gas from the separator to the outside of the device. The transfer conduit includes an internal means for generating a helical flow in the gas-liquid mixture, such as a helical insert or a spiral insert. The vortex separator is located at the top of the transfer conduit and includes a separation means for separating the gas-liquid mixture into a liquid-rich stream and a gas-rich stream. The separation means may be a separator conduit that extends from the top of the vortex separator to the upper opening of the transfer conduit, is aligned with the gas-rich outlet, and has substantially the same cross-sectional dimensions as the outlet. The gas-rich outlet conduit is used to send the gas-rich stream to the outside of the device.

[0017] The transfer conduit generally may be of any cross-sectional shape, so long as the gas-liquid mixture flows vertically upward within the conduit. Convenient, available conduit shapes, such as reactor-grade piping, are suitable, preferably designed to allow for an adequate gas-liquid mixture flow rate and minimal pressure drop. Typical pipe diameters range from about 2 to 8 inches (about 5.1 to 20.3 cm), or 4 to 6 inches (about 10.2 to 15.2 cm), or even about 5 inches (about 12.7 cm). The transfer conduit may comprise a lower section and an upper section, which are open at both ends and configured to fit together at corresponding ends to form the conduit. In such cases, the upper section may comprise internal means for inducing a helical flow in the gas-liquid mixture flowing through the conduit, and the lower section is configured to allow the gas-liquid mixture to enter the lower opening, pass through the lower section, and enter the lower end of the upper section of the conduit. Typically, the internal means for inducing helical flow in the liquid-gas mixture can be a spiral or helical insert having a length substantially equal to the length of the upper section of the transfer conduit, the insert being disposed within the upper section from top to bottom of the upper section and having substantially the same dimensions as the internal cross section of the transfer conduit. Other structures or inserts for inducing helical flow within the transfer conduit can also be used. When the separator is installed within the flow-through pan of an ebullated bed reactor, the lower section of the transfer conduit is typically adapted to fit into a corresponding opening in the flow-through pan so that the gas-liquid mixture can enter the separation device from the lower section of the reactor.

[0018] The vortex separator is open at the bottom and has a larger cross-sectional area and dimensions than the transfer conduit so that the vortex separator can fit over the upper portion of the transfer conduit. Thus, the vortex separator can be positioned over the top (upper portion) of the transfer conduit and extend below the top of the transfer conduit. Generally, the vortex separator is sized to provide a liquid flow path between the exterior of the transfer conduit and the overlapping interior of the vortex separator. A separator having a circular vortex separator and a transfer conduit, when installed in a flow-through pan of an ebullated bed reactor, creates an annular liquid flow path between the exterior of the transfer conduit and the interior of the separator. The vortex separator may typically be a substantially circular section or tube section having a diameter in the range of about 4 to 12 inches (about 10.2 to 30.5 cm), or 6 to 10 inches (about 15.2 to 25.4 cm), or 6 to 9 inches (about 15.2 to 22.9 cm), or 7 to 9 inches (about 17.8 to 22.9 cm), or about 8 inches (about 20.3 cm). The term "substantially" in this context is intended to mean normal variations in dimensions expected by one of ordinary skill in the art.

[0019] The internal separation means for separating a gas-liquid mixture into a liquid-rich stream and a gas-rich stream within a vortex separator generally utilizes the separation of liquid and gas induced within the vortex to separate the two phases into a liquid-rich stream and a gas-rich stream. Each stream is directed to a corresponding gas-rich or liquid-rich outlet. In some cases, the gas-rich outlet may be located at the top of the vortex separator, e.g., the outlet may be an opening in the top plate. In that case, the internal separation means may include, for example, a separator conduit extending from the top of the vortex separator to the upper opening of the transfer conduit. In such a case, the separator conduit may be aligned with the gas-rich outlet in the top plate and have substantially the same cross-sectional dimensions as the gas-rich outlet.

[0020] A top plate is also present above the vortex separator. When the gas-rich stream flows vertically through the top of the vortex separator, the top plate includes a gas-rich outlet sized to allow the gas-rich stream to enter the gas-rich outlet conduit from the vortex separator. A separation means, such as a conduit or pipe section, is typically aligned with the gas-rich outlet of the top plate to allow gas separated in the vortex separator to enter the gas-rich outlet conduit. The gas-rich outlet and the conduit used as the separation means typically have substantially the same cross-sectional dimensions, or, in the case of a pipe, the same diameter. The separator conduit typically has a cross-sectional area and dimensions smaller than those of the transfer conduit. The internal separating means may typically be a substantially circular or tubular section having a diameter in the range of about 1 to 6 inches (about 2.5 to 15.2 cm), or 1 to 4 inches (about 2.5 to 10.2 cm), or 1 to 3 inches (about 2.5 to 7.6 cm), or 2 to 3 inches (about 5.1 to 7.6 cm), or a diameter of about 2.5 inches (about 6.4 cm). The term "substantially" in this context is intended to mean normal variations in dimensions expected by one of ordinary skill in the art.

[0021] The gas-rich outlet conduit generally has a larger cross-sectional area or diameter than the separator conduit and a smaller cross-sectional area or diameter than the vortex separator. The outlet conduit may be angled to direct the gas flow in a desired direction. In ebullated bed reactor systems, the outlet conduit may be an elbow, typically oriented at an angle of about 30 to 60 degrees from the horizontal. In flow-through pan systems, the outlet flow direction may also be oriented relative to the periphery of the pan; for example, the outlet elbow may be oriented at an angle of about 15 to 60 degrees from the radial direction of the separation device relative to the center of the reactor.

[0022] Generally, the transfer conduit, internal spiral flow means, vortex separator, internal separation means, gas-rich outlet, and gas-rich outlet conduit may all be aligned about the same vertical axis. For installation on the flow-through pan of an ebullated bed reactor, such an arrangement creates a substantially vertical flow path through the device to the separation means. The gas-rich stream continues vertically upward and exits the device through the gas-rich outlet conduit. The liquid-rich stream is diverted downward to the liquid outlet, flows onto the pan, and flows downward through the downcomer.

[0023] Various support structures can be used to support the separation device when it is installed in a reactor or when used in another application. For example, when installed in the flow-through pan of an ebullated bed reactor, the opening of the lower portion of the transfer conduit can be welded or otherwise supported on the flow-through pan, for example, by a brace mounted within the reactor.

[0024] The invention further relates to the use of the separation device in any application which may require separation of gas and liquid from a gas-liquid mixture, and to any apparatus in which the separation device is installed, such as a flow-through (circulating) pan or sprayed bed reactor.

[0025] The present invention further relates to a process for separating gas and liquid in a gas-liquid mixture. The process generally includes passing the gas-liquid mixture vertically through a conduit having an internal means to induce a vertical helical flow in the gas-liquid mixture flowing vertically through the conduit; passing the helical-flow gas-liquid mixture through a vortex separator, wherein the helical-flow gas-liquid mixture contacts a separation conduit aligned substantially parallel to the vertical flow path of the helical-flow gas-liquid mixture along its length, thereby forming a liquid-rich stream outside the separation conduit and a gas-rich stream inside the separation conduit; and directing the liquid-rich stream to a liquid-rich outlet and the gas-rich stream to a separate gas-rich outlet. This process can be used with one or more separators described herein to separate gas and liquid from the gas-liquid mixture, particularly in flow-through pan and ebullated bed reactor applications.

[0026] In an embodiment of the present invention, as represented by Figures 1-3, a separation device can have the cross-sectional view shown in Figure 1. The transfer conduit can include a transfer conduit lower section 10 and a transfer conduit upper section 20, which include a junction 25 between the lower and upper sections. The transfer conduit includes a lower opening outlet 30 and an upper opening outlet 40. An internal separation means, such as a spiral insert 50, is shown in the upper section. A vortex separator 60 is shown including an internal separation conduit 70, an upper plate 75, a liquid-rich outlet 80, and a gas-rich outlet 90. The gas-rich outlet conduit 100 is shown having an angular orientation of approximately 45 degrees relative to the horizontal and an outlet elbow orientation of approximately 30 degrees from the radial direction of the separation device relative to the center of the reactor.

[0027] Figure 2 shows an isometric view of the exterior of a separation device. As shown, the separation device includes the same transport conduit configuration of Figure 1, including a transport conduit lower section 10 and a transport conduit upper section 20, along with a junction 25 between the lower and upper sections. Also included in Figure 2 for illustrative purposes are a vortex separator 60, an upper plate 75, a liquid-rich outlet opening 80 (located in the annular region between the vortex separator and the exterior of the transport conduit), and a gas-rich outlet conduit 100. While Figures 1 and 2 show one embodiment of a possible device configuration, other configurations may be used.

[0028] 3 shows an embodiment of the invention in which multiple separation devices 110 are installed in a flow-through pan 120 above an ebullated bed reactor 130. A downcomer 140 and reactor effluent outlet 150 are also shown.

[0029] The separation devices and related aspects of the present invention, including the specific embodiments described herein, provide particular advantages and improvements in hydroprocessing applications, including improved gas-liquid separation and reduced gas entrainment in downcomer liquid streams in ebullated bed facilities.

[0030] The foregoing description of one or more embodiments of the invention is primarily for purposes of illustration, and it will be recognized that many variations may be used which still incorporate the essence of the invention. In determining the scope of the invention, reference should be made to the following claims.

[0031] All patents and publications cited in the foregoing description of the invention are hereby incorporated by reference.

Claims

1. 1. A gas-liquid separator adapted to separate liquid and gas in an ebullated bed reactor under operating conditions, the separation device comprising: a transfer conduit for transferring a gas-liquid mixture from a lower portion of an ebullated bed reactor to an upper portion of said reactor, said conduit being oriented vertically within said reactor during operation, said conduit having a lower opening and an upper opening, said conduit comprising internal means for inducing a helical flow in the liquid-gas mixture flowing vertically through said conduit; a vortex separator located adjacent to an upper portion of the upper opening of the transfer conduit, the vortex separator comprising: an internal separating means for separating the gas-liquid mixed stream into a liquid-rich stream and a gas-rich stream; an upper plate; an outlet for the liquid-rich stream; and an outlet for the gas-rich stream; a gas-rich outlet conduit located adjacent a top of the vortex separator and in fluid communication with the gas-rich outlet of the vortex separator; The gas-liquid separator.

2. 2. The separator of claim 1, wherein the transfer conduit comprises a lower section and an upper section, the lower section and the upper section being open at opposite ends and adapted to fit together at corresponding ends to form the conduit, the upper section comprising the internal means for imparting helical flow in a gas-liquid mixture flowing through the conduit, and the lower section being adapted to allow the gas-liquid mixture to enter the lower opening, pass through the lower section, and enter the lower end of the upper conduit section.

3. 3. The separator of claim 2, wherein the transfer conduit lower section is adapted to fit into a corresponding opening in a flow-through pan of an ebullated bed reactor so that a gas-liquid mixture can enter the separation device from the lower section of the reactor.

4. 4. The separator of claim 2, wherein the upper and lower portions of the transfer conduit are substantially circular or tubular sections having diameters in the range of about 2 to 8 inches (about 5.1 to 20.3 cm).

5. 5. A separator according to claim 2, wherein the internal means for inducing a spiral flow in the liquid-gas mixture is a spiral or helical insert having substantially the same length as the length of the upper section of the transfer conduit, the insert being disposed within the upper section of the transfer conduit from top to bottom of the upper section and having substantially the same dimensions as the internal cross section of the transfer conduit.

6. 6. The separator of claim 1, wherein the vortex separator is open at the bottom, has a cross-sectional area and dimensions larger than those of the transfer conduit, is positioned over the top of the transfer conduit, and extends below the top of the transfer conduit.

7. 7. The separator of claim 6, wherein the vortex separator is sized to provide a liquid flow path between an exterior of the conduit and an interior of the vortex separator.

8. 8. The separator of claim 1, wherein the vortex separator is a substantially circular section or tube section having a diameter in the range of about 4 to 12 inches (about 10.2 cm to 30.5 cm).

9. The separator of claim 7 , wherein the liquid-rich outlet comprises the liquid flow path.

10. The separator according to any one of claims 1 to 9, wherein the gas-rich outlet is located at the top of the vortex separator.

11. 11. A separator according to any preceding claim, wherein the internal separation means comprises a separator conduit extending from the upper portion of the vortex separator to an upper opening of the transfer conduit, the separator conduit being aligned with the gas-rich outlet and having substantially the same cross-sectional dimensions as the outlet.

12. A separator according to any preceding claim, wherein the internal separating means comprises a separator conduit having a cross-sectional area and dimensions smaller than those of the transfer conduit.

13. 13. The separator of any one of claims 1 to 12, wherein the internal separating means is a substantially circular section or tubular section having a diameter in the range of about 1 to 6 inches (about 2.5 cm to 15.2 cm).

14. 14. The separator of any one of claims 1 to 13, wherein the transfer conduit, the internal helical flow means, the vortex separator, the internal separation means, the gas-rich outlet, and the gas-rich outlet conduit are aligned about the same vertical axis.

15. A flow-through pan gas-liquid separator for an ebullated bed reactor, comprising a plurality of separators according to any one of claims 1 to 14.

16. 16. An ebullated bed reactor comprising the flow-through pan gas-liquid separator of claim 15.

17. 1. A process for separating gas and liquid in a gas-liquid mixture, comprising: passing a gas-liquid mixture vertically through a conduit having an internal means to induce a vertical helical flow in the gas-liquid mixture flowing vertically through the conduit; passing the spirally flowing gas-liquid mixture through a vortex separator, wherein the spirally flowing gas-liquid mixture contacts a separation conduit aligned substantially parallel to the vertical flow path of the spirally flowing gas-liquid mixture along its length, thereby forming a liquid-rich stream outside the separation conduit and a gas-rich stream inside the separation conduit; directing the liquid-rich stream to a liquid-rich outlet and directing the gas-rich stream to a separate gas-rich outlet; The process comprising:

18. 18. The process of claim 17, wherein a plurality of separators according to any one of claims 1 to 14 are used to separate the gas and the liquid from the gas-liquid mixture.

19. 20. The process of claim 18, wherein the process is carried out using a flow-through pan gas-liquid separator as defined in claim 15.

20. 19. The process of claim 18, wherein the process is carried out in an ebullated bed reactor of claim 16.

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