Top-reduced gas desulfurization system

Abstract

The utility model relates to the technical field of petrochemical engineering, in particular to a vacuum top gas desulfurization system, which comprises an absorption tank, a first desulfurization ejector, a circulating pump, a vacuum top oil tank and a first gas delivery pipe, a liquid inlet end of the circulating pump is communicated with the absorption tank, and a liquid outlet end of the circulating pump is communicated with a liquid inlet of the desulfurization ejector. One end of the first gas conveying pipe is connected with a gas outlet of the vacuum oil tank, the other end of the first gas conveying pipe is connected with a gas inlet of the first desulfurization ejector, the middle of the first gas conveying pipe is provided with a bent section protruding upwards, and the bent section protruding upwards can prevent absorption liquid in the ejector from reversely flowing into the vacuum oil tank, so that the absorption liquid is prevented from flowing into the vacuum oil tank. And the quality of oil products produced by the oil refining system is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of petrochemical industry, in particular to a top-reducing gas desulfurization system. Background Art

[0002] Crude oil processing produces high sulfur gas, with the hydrogen sulfide content in top-cut gas reaching as high as 30%. Top-cut gas is typically burned as fuel in heating furnaces or, due to its small volume, vented directly. To meet environmental emission requirements, it must be desulfurized.

[0003] Chinese invention patent publication number CN102061206A discloses a method for desulfurizing vacuum gas. A circulating pump draws absorption liquid from a suction recovery tank into the liquid inlet of an ejector. The desulfurized gas flowing from the desulfurizing tank flows through a gas pipeline into the ejector's air inlet. The desulfurized gas and absorption liquid are thoroughly mixed within the ejector, absorbing the hydrogen sulfide in the desulfurized gas. When the desulfurized gas and liquid absorption liquid are mixed using an ejector, a small amount of absorption liquid can flow back from the ejector's air inlet into the gas pipeline used to transport the desulfurized gas. This can affect the smooth operation of the desulfurizing tank and adversely affect the quality of the oil produced by the refining system. Utility Model Content

[0004] The technical problem to be solved by the utility model is that in the existing identification gas desulfurization method, the absorption liquid in the ejector will flow back into the reduced-top oil tank, which has an adverse effect on the quality of the oil produced by the oil refining system.

[0005] In order to solve the above technical problems, the purpose of the present utility model is to provide a top-reducing gas desulfurization system, including an absorption tank, a first desulfurization ejector, a circulation pump, a top-reducing oil tank and a first gas pipe, the liquid inlet end of the circulation pump is connected to the absorption tank, the liquid outlet end of the circulation pump is connected to the liquid inlet of the desulfurization ejector, one end of the first gas pipe is connected to the gas outlet of the top-reducing oil tank, and the other end of the first gas pipe is connected to the air inlet of the first desulfurization ejector. The middle part of the first gas pipe is provided with a bent section protruding upward.

[0006] As a preferred solution, the bending section is an inverted U-shaped structure.

[0007] As a preferred solution, the top-reduced gas desulfurization system includes a cooler, a first end of the cooler is connected to the liquid outlet of the circulation pump, and a second end of the cooler is connected to the liquid inlet of the first desulfurization ejector.

[0008] As a preferred solution, the liquid outlet end of the circulation pump is connected to a spare pipe in parallel with the cooler, the end of the spare pipe away from the circulation pump is connected to the liquid inlet of the first desulfurization injector, and a first control valve is provided in the spare pipe; the first end of the cooler is connected to a first pipe body in parallel with the spare pipe, the end of the first pipe body away from the cooler is connected to the liquid outlet of the circulation pump, and a second control valve is provided in the first pipe body.

[0009] As a preferred solution, the second end of the cooler is connected to a second pipe body in parallel with the backup pipe, the end of the second pipe body away from the cooler is connected to the liquid inlet of the first desulfurization injector, and a third control valve is provided in the second pipe body.

[0010] As a preferred solution, the top-reducing gas desulfurization system includes a third pipe body, a fourth pipe body, a fifth pipe body, a second gas pipe and a second desulfurization injector, one end of the second gas pipe is connected to the gas outlet of the top-reducing oil tank, and the other end of the second gas pipe is connected to the air inlet of the second desulfurization injector; the first end of the third pipe body is connected to the liquid outlet of the circulating pump, the second end of the third pipe body is connected to the first end of the fourth pipe body and the first end of the fifth pipe body, the second end of the fourth pipe body is connected to the liquid inlet of the first desulfurization injector, and the second end of the fifth pipe body is connected to the liquid inlet of the second desulfurization injector. A fourth control valve is provided in the first gas pipe, a fifth control valve is provided in the second gas pipe, a sixth control valve is provided in the fourth pipe body, and a seventh control valve is provided in the fifth pipe body.

[0011] As a preferred solution, a flow regulating valve is provided in the third pipe body.

[0012] As a preferred solution, the top-reduced gas desulfurization system includes an absorption liquid supply device and an absorption liquid treatment device. A first cavity and a second cavity are provided in the absorption tank. The first cavity is connected to the absorption liquid supply device, and the liquid inlet end of the circulation pump is connected to the first cavity; the liquid outlet end of the first desulfurization ejector is connected to the second cavity, and the absorption liquid treatment device is connected to the second cavity.

[0013] As a preferred solution, the top-reduced gas desulfurization system includes a controller and a liquid pump, the liquid inlet of the liquid pump is connected to the bottom of the second cavity, a liquid level gauge is provided in the second cavity, and the liquid level gauge and the liquid pump are both electrically connected to the controller.

[0014] As a preferred solution, a vent is provided on the top of the second cavity, the vent is connected to a sixth tube, and one end of the sixth tube away from the absorption tank is connected to the pressure reducing furnace.

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] The utility model discloses a degassing gas desulfurization system, comprising an absorption tank, a first desulfurization ejector, a circulation pump, a degassing oil tank and a first gas pipeline, wherein the liquid inlet end of the circulation pump is connected to the absorption tank, the liquid outlet end of the circulation pump is connected to the liquid inlet of the desulfurization ejector, one end of the first gas pipeline is connected to the gas outlet of the degassing oil tank, and the other end of the first gas pipeline is connected to the gas inlet of the first desulfurization ejector, and the middle part of the first gas pipeline is provided with an upwardly protruding bent section, and the upwardly protruding bent end can prevent the absorption liquid in the ejector from flowing back into the degassing oil tank, thereby avoiding the liquid soap from flowing into the degassing oil tank and ensuring the quality of the oil products produced by the refining system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic structural diagram of the top-reducing gas desulfurization system of the present invention;

[0018] In the figure, 1. absorption tank, 21. first desulfurization ejector, 22. second desulfurization ejector, 3. circulation pump, 41. first gas pipeline, 42. second gas pipeline, 411. bending section, 5. cooler, 6. spare pipe, 71. first control valve, 72. second control valve, 73. third control valve, 74. fourth control valve, 75. fifth control valve, 76. sixth control valve, 77. seventh control valve, 81. first pipe body, 82. second pipe body, 83. third pipe body, 84. fourth pipe body, 85. fifth pipe body, 86. sixth pipe body, 87. seventh pipe body, 91. flow regulating valve, 92. absorption liquid supply device, 93. absorption liquid treatment device, 94. liquid pump, 95. liquid level meter. DETAILED DESCRIPTION

[0019] The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0020] In the description of the present invention, it should be understood that the terms "upper", "lower", "left", "right", "top", "bottom", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. It should be understood that the terms "first", "second", etc. are used in the present invention to describe various information, but such information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of the present invention, "first" information may also be referred to as "second" information, and similarly, "second" information may also be referred to as "first" information.

[0021] like Figure 1 As shown, a preferred embodiment of the degassing gas desulfurization system of the present invention includes an absorption tank 1, a first desulfurization ejector 21, a circulating pump 3, a degassing oil tank and a first gas pipe 41, the liquid inlet end of the circulating pump 3 is connected to the absorption tank 1, the liquid outlet end of the circulating pump 3 is connected to the liquid inlet of the desulfurization ejector, one end of the first gas pipe 41 is connected to the gas outlet of the degassing oil tank, and the other end of the first gas pipe 41 is connected to the gas inlet of the first desulfurization ejector 21, and the middle part of the first gas pipe 41 is provided with an upwardly protruding bent section 411; the upwardly protruding bent end can prevent the absorption liquid in the ejector from flowing back into the degassing oil tank, thereby avoiding the absorption liquid from flowing into the degassing oil tank and ensuring the quality of the oil products produced by the refining system.

[0022] Specifically, the bending section 411 is an inverted U-shaped structure; the U-shaped structure can not only prevent the backflow of the absorption liquid, but also ensure the smooth flow of the top-reducing gas airflow in the gas pipeline, and avoid excessive airflow resistance generated by the bending section 411. In other embodiments of the present invention, the bending section 411 can be V-shaped.

[0023] In this embodiment, the absorption liquid is a methyldiethanolamine solution. Hydrogen sulfide is a proton-donating acid. When reacting with methyldiethanolamine, hydrogen sulfide ions are formed via a proton transfer reaction. This reaction is very fast, almost instantaneous, and is a condensation reaction.

[0024] The reaction formula is as follows:

[0025] (CH3)N(CH2CH2OH)2+H2S=(CH3)N.H2S.(CH2CH2OH)2

[0026] From the above reaction equation, we can see that methyldiethanolamine absorbs hydrogen sulfide at a rate of 1 mol per mol of methyldiethanolamine. Utilizing this mechanism, a methyldiethanolamine solution serves as the working medium of the pressurized desulfurization ejector. Circulating pump 3 pressurizes the methyldiethanolamine solution to 1.9 MPa, serving as the motive medium for the desulfurization ejector. The high-pressure methyldiethanolamine solution flows through a nozzle at high velocity into the mixing chamber, where it mixes thoroughly with the top-cut gas at approximately 40°C to 80°C, exchanging energy. After thorough contact and reaction, the desulfurizer absorbs the hydrogen sulfide from the top-cut gas. The top-cut gas is then pressurized to 200 kPa, allowing it to be better absorbed by the desulfurizer at this higher pressure. Simultaneously, the top-cut gas is pressurized to the required discharge pressure. The hydrogen sulfide-rich methyldiethanolamine solution is then heated to 120°C with steam under low acid gas partial pressure for stripping and regeneration, releasing the absorbed hydrogen sulfide. The separated methyldiethanolamine solution can be reused as fresh liquid for regeneration.

[0027] In this embodiment, the top gas desulfurization system includes a cooler 5, a first end of the cooler 5 is connected to the liquid outlet of the circulation pump 3, and a second end of the cooler 5 is connected to the liquid inlet of the first desulfurization ejector 21. Specifically, the cooler 5 is a water cooler, and the cooler 5 cools the methyldiethanolamine solution to about 35°C. To avoid the impact of the maintenance of the cooler 5 on the top gas desulfurization system, in this embodiment, the liquid outlet of the circulation pump 3 is connected to a spare pipe 6 in parallel with the cooler 5, and the end of the spare pipe 6 away from the circulation pump 3 is connected to the liquid inlet of the first desulfurization ejector 21, and a first control valve 71 is provided in the spare pipe 6; the first end of the cooler 5 is connected to a first pipe body 81 in parallel with the spare pipe 6, and the end of the first pipe body 81 away from the cooler 5 is connected to the liquid outlet of the circulation pump 3, and a second control valve 72 is provided in the first pipe body 81. Specifically, when the cooler 5 needs to be repaired or maintained, the first control valve 71 is opened and the second control valve 72 is closed, and the circulation pump 3 is connected to the desulfurization ejector through the spare pipe 6, so that the top gas desulfurization system can be kept running without cooling the absorption liquid.

[0028] Furthermore, a second pipe 82 is connected to the second end of the cooler 5 in parallel with the backup pipe 6. The end of the second pipe 82 away from the cooler 5 is connected to the liquid inlet of the first desulfurization injector 21. A third control valve 73 is installed in the second pipe 82. When the cooler 5 needs to be repaired or maintained, the second and third control valves 72 and 73 are closed simultaneously.

[0029] The current top-removal gas desulfurization system mostly uses a single desulfurization injector, which cannot be individually cut out for processing and maintenance. When the desulfurization injector needs to be cut out for maintenance due to blockage or other reasons, the entire top-removal gas desulfurization system needs to be washed and replaced with water, which increases the unit consumption of desalted water and the workload of the device. In this embodiment, the top-reducing gas desulfurization system includes a third pipe body 83, a fourth pipe body 84, a fifth pipe body 85, a second gas pipe 42 and a second desulfurization injector 22. One end of the second gas pipe 42 is connected to the gas outlet of the top-reducing oil tank, and the other end of the second gas pipe 42 is connected to the air inlet of the second desulfurization injector 22; the first end of the third pipe body 83 is connected to the liquid outlet of the circulating pump 3, the second end of the third pipe body 83 is connected to the first end of the fourth pipe body 84 and the first end of the fifth pipe body 85, the second end of the fourth pipe body 84 is connected to the liquid inlet of the first desulfurization injector 21, and the second end of the fifth pipe body 85 is connected to the liquid inlet of the second desulfurization injector 22. A fourth control valve 74 is provided in the first gas pipe 41, a fifth control valve 75 is provided in the second gas pipe 42, a sixth control valve 76 is provided in the fourth pipe body 84, and a seventh control valve 77 is provided in the fifth pipe body 85. When the first desulfurization injector 21 needs to be repaired, the second desulfurization injector 22 is switched to an operational state, while the first desulfurization injector 21 is switched to an inoperative state. This does not affect the normal operation of the top-reducing gas desulfurization system, and there is no need to perform water washing and replacement of the entire top-reducing gas desulfurization system. Furthermore, to facilitate control of the flow of absorption liquid into the first and second desulfurization injectors 21, 22, a flow regulating valve 91 is provided in the third pipe body 83 in this embodiment.

[0030] In this embodiment, the top gas desulfurization system includes an absorption liquid supply device 92 and an absorption liquid recovery device. A first cavity and a second cavity are provided in the absorption tank 1. The first cavity is connected to the absorption liquid supply device 92, and the liquid inlet end of the circulation pump 3 is connected to the first cavity; the liquid outlet end of the first desulfurization ejector 21 is connected to the second cavity, and the absorption liquid recovery device is connected to the second cavity.

[0031] The top-removal gas desulfurization system includes a controller and a liquid pump 94. The liquid inlet of liquid pump 94 is connected to the bottom of the second chamber, and the liquid outlet of liquid pump 94 is connected to the liquid inlet of the absorption liquid recovery device. A liquid level gauge 95 is provided in the second chamber. Both liquid level gauge 95 and liquid pump 94 are electrically connected to the controller. When the liquid level in the second chamber is higher than the position of liquid level gauge 95, liquid pump 94 discharges the liquid in the second chamber to the absorption liquid recovery device, thereby preventing the adverse effects of excessively high liquid levels in the second chamber on the top-removal gas desulfurization system.

[0032] In this embodiment, a vent is provided at the top of the second chamber. This vent is connected to a sixth tube 86. The end of the sixth tube 86, remote from the absorption tank 1, is connected to a pressure-reducing furnace. The treated top-reducing gas entering the pressure-reducing furnace flows into the furnace for combustion. In other embodiments of the present invention, the vent is further connected to a seventh tube 87, which is used to transport the treated top-reducing gas to the flare line.

[0033] In summary, the degassing gas desulfurization system of the present invention includes an absorption tank 1, a first desulfurization ejector 21, a circulating pump 3, a degassing oil tank and a first gas pipe 41. The liquid inlet end of the circulating pump 3 is connected to the absorption tank 1, and the liquid outlet end of the circulating pump 3 is connected to the liquid inlet of the desulfurization ejector. One end of the first gas pipe 41 is connected to the gas outlet of the degassing oil tank, and the other end of the first gas pipe 41 is connected to the gas inlet of the first desulfurization ejector 21. The middle part of the first gas pipe 41 is provided with an upwardly protruding bent section 411. The upwardly protruding bent end can prevent the absorption liquid in the ejector from flowing back into the degassing oil tank, thereby avoiding the absorption liquid from flowing into the degassing oil tank and ensuring the quality of the oil products produced by the refining system.

[0034] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and replacements can be made without departing from the technical principles of the present invention. These improvements and replacements should also be regarded as the scope of protection of the present invention.

Claims

1. A top-reducing gas desulfurization system, characterized in that: The invention comprises an absorption tank (1), a first desulfurization ejector (21), a circulation pump (3), a degassing oil tank and a first gas pipe (41), wherein the liquid inlet end of the circulation pump (3) is connected to the absorption tank (1), the liquid outlet end of the circulation pump (3) is connected to the liquid inlet of the desulfurization ejector, one end of the first gas pipe (41) is connected to the gas outlet of the degassing oil tank, the other end of the first gas pipe (41) is connected to the gas inlet of the first desulfurization ejector (21), and the middle part of the first gas pipe (41) is provided with a bent section (411) protruding upward.

2. The top-reduced gas desulfurization system according to claim 1, characterized in that: The bending section (411) is an inverted U-shaped structure.

3. The top-removal gas desulfurization system according to claim 1, characterized in that: The top-reduced gas desulfurization system comprises a cooler (5), a first end of the cooler (5) being connected to the liquid outlet of the circulation pump (3), and a second end of the cooler (5) being connected to the liquid inlet of the first desulfurization ejector (21).

4. The top-removal gas desulfurization system according to claim 3, characterized in that: The liquid outlet end of the circulation pump (3) is connected to a spare pipe (6) in parallel with the cooler (5), and one end of the spare pipe (6) away from the circulation pump (3) is communicated with the liquid inlet of the first desulfurization ejector (21), and a first control valve (71) is provided in the spare pipe (6); the first end of the cooler (5) is connected to a first pipe body (81) in parallel with the spare pipe (6), and one end of the first pipe body (81) away from the cooler (5) is communicated with the liquid outlet of the circulation pump (3), and a second control valve (72) is provided in the first pipe body (81).

5. The top-removed gas desulfurization system according to claim 4, characterized in that: The second end of the cooler (5) is connected to a second pipe body (82) in parallel with the standby pipe (6); the end of the second pipe body (82) away from the cooler (5) is connected to the liquid inlet of the first desulfurization injector (21); and a third control valve (73) is provided in the second pipe body (82).

6. The top-removal gas desulfurization system according to claim 1, characterized in that: The degassing gas desulfurization system comprises a third pipe body (83), a fourth pipe body (84), a fifth pipe body (85), a second gas pipeline (42) and a second desulfurization ejector (22), one end of the second gas pipeline (42) is connected to the gas outlet of the degassing oil tank, and the other end of the second gas pipeline (42) is connected to the gas inlet of the second desulfurization ejector (22); the first end of the third pipe body (83) is connected to the liquid outlet of the circulation pump (3), and the second end of the third pipe body (83) is connected to the liquid outlet of the fourth pipe body (84). The first end and the first end of the fifth tube body (85), the second end of the fourth tube body (84) are connected to the liquid inlet of the first desulfurization injector (21), the second end of the fifth tube body (85) is connected to the liquid inlet of the second desulfurization injector (22), a fourth control valve (74) is provided in the first gas pipeline (41), a fifth control valve (75) is provided in the second gas pipeline (42), a sixth control valve (76) is provided in the fourth tube body (84), and a seventh control valve (77) is provided in the fifth tube body (85).

7. The top-removed gas desulfurization system according to claim 6, characterized in that: A flow regulating valve (91) is provided in the third tube body (83).

8. The top-removal gas desulfurization system according to claim 1, characterized in that: The top-reduced gas desulfurization system includes an absorption liquid supply device (92) and an absorption liquid treatment device (93). A first cavity and a second cavity are provided in the absorption tank (1). The first cavity is connected to the absorption liquid supply device (92), and the liquid inlet end of the circulation pump (3) is connected to the first cavity; the liquid outlet end of the first desulfurization ejector (21) is connected to the second cavity, and the absorption liquid treatment device (93) is connected to the second cavity.

9. The top-removed gas desulfurization system according to claim 8, characterized in that: The top-reduced gas desulfurization system includes a controller and a liquid pump (94), wherein the liquid inlet of the liquid pump (94) is connected to the bottom of the second cavity, and a liquid level meter (95) is provided in the second cavity. The liquid level meter (95) and the liquid pump (94) are both electrically connected to the controller.

10. The top-removed gas desulfurization system according to claim 8, characterized in that: A vent is provided at the top of the second cavity, and the vent is connected to a sixth tube (86). An end of the sixth tube (86) away from the absorption tank (1) is connected to the pressure reducing furnace.

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