Device for reducing energy consumption of reciprocating compressor of light hydrocarbon recovery device

Abstract

The invention relates to a device for reducing energy consumption of a reciprocating compressor of a light hydrocarbon recovery device, which comprises a feed gas compressor, the feed gas compressor is connected with a desulfurization tower and a molecular sieve tower, the molecular sieve tower is connected with a first expansion machine, one side of the first expansion machine is connected with a first cold box, and the other side of the first expansion machine is connected with a second cold box. A second expansion machine is arranged between the feed gas compressor and the desulfurizing tower, the feed gas compressor is oppositely communicated with the pressurizing end of the second expansion machine, and a circulating cooling device is further arranged between the feed gas compressor and the desulfurizing tower. The application has the effects of reducing the outlet pressure of the reciprocating compressor and reducing the feed gas inlet temperature of the cold box I of the light hydrocarbon recovery device, thereby achieving the effects of reducing the energy consumption of the reciprocating compressor and improving the operation efficiency and yield of the light hydrocarbon recovery device.

Description

Technical Field

[0001] The present application relates to the field of light hydrocarbon separation and purification technology in the petrochemical production process, and in particular to a device for reducing the energy consumption of a reciprocating compressor of a light hydrocarbon recovery device. Background Art

[0002] Light hydrocarbon recovery equipment is generally divided into a raw gas boosting unit, a desulfurization unit, a molecular sieve dehydration unit, an expansion refrigeration unit, and a distillation unit, which separates the raw natural gas into three products: purified natural gas, liquefied petroleum gas, and stable light hydrocarbons.

[0003] The raw gas boosting unit generally uses a motor-driven reciprocating compressor for boosting. The reciprocating compressor is the main power-consuming equipment of the whole device. The outlet pressure of the reciprocating compressor determines the power of the reciprocating compressor. The higher the outlet pressure, the greater the power and energy consumption of the reciprocating compressor; the lower the reciprocating outlet pressure, the smaller the power and energy consumption of the reciprocating compressor.

[0004] The light hydrocarbon recovery unit uses a cryogenic condensation process to separate heavy components above C3 in natural gas. It is necessary to reduce the refrigeration temperature of the unit as much as possible to improve the operating efficiency and yield of the unit. Referring to the accompanying figure 1, the raw gas inlet temperature of the cold box 1 is the main factor restricting the yield of the light hydrocarbon recovery unit. The lower the raw gas inlet temperature of the cold box 1, the higher the yield of the light hydrocarbon recovery unit. The higher the raw gas inlet temperature of the cold box 1, the lower the yield of the light hydrocarbon recovery unit.

[0005] With respect to the above-mentioned related technologies, the inventors believe that during summer, affected by the ambient temperature, the raw gas inlet temperature of cold box 1 will rise to 40°C, and the efficiency and yield of the light hydrocarbon recovery device will drop significantly. Summary of the invention

[0006] In order to reduce the outlet pressure of the reciprocating compressor and the inlet temperature of the raw gas of the cold box of the light hydrocarbon recovery device, thereby reducing the energy consumption of the reciprocating compressor and improving the operating efficiency and yield of the light hydrocarbon recovery device, the present application provides a device for reducing the energy consumption of the reciprocating compressor of the light hydrocarbon recovery device.

[0007] The present application provides a device for reducing the energy consumption of a reciprocating compressor of a light hydrocarbon recovery device, which adopts the following technical solution:

[0008] A device for reducing the energy consumption of a reciprocating compressor of a light hydrocarbon recovery device, comprising a raw gas compressor, to which a desulfurization tower and a molecular sieve tower are connected, to which a first expander is connected, and a cold box is connected on one side of the first expander, a second expander is arranged between the raw gas compressor and the desulfurization tower, the raw gas compressor and the boosting end of the second expander are relatively connected, and a circulating cooling device is also arranged between the raw gas compressor and the desulfurization tower.

[0009] By adopting the above technical solution, the expander can perform secondary pressurization on the natural gas at the outlet of the raw gas compressor, thereby reducing the outlet pressure of the raw gas compressor. The temperature of the pressurized natural gas can be reduced by the circulating cooling device, thereby reducing the outlet pressure of the reciprocating compressor and the inlet temperature of the raw gas of the cold box of the light hydrocarbon recovery device, thereby reducing the energy consumption of the reciprocating compressor and improving the operating efficiency and yield of the light hydrocarbon recovery device.

[0010] Optionally, the circulating cooling device includes a circulating water cooler, one end of the circulating water cooler is provided with a circulating cooling water inlet, and the other end of the circulating water cooler is provided with a circulating cooling water outlet.

[0011] By adopting the above technical scheme, the cooling liquid is introduced into the interior of the circulating water cooler from the circulating cooling water inlet, and the cooled liquid is discharged from the circulating cooling water outlet position, so that the gas discharged from the raw gas compressor is cooled by the circulating water cooler, the energy consumption of the compressor is reduced, and the operating efficiency and yield of the light hydrocarbon recovery device are improved.

[0012] Optionally, a heat exchange cold box is fixedly connected to the raw material gas flow channel inlet pipeline of the cold box one, and the heat exchange cold box is relatively connected to the cold box one.

[0013] Optionally, the second expansion end of the second expander is connected to a high-pressure natural gas inlet, and the high-pressure natural gas inlet can drive the impeller of the second expansion end of the second expander to rotate.

[0014] By adopting the above technical solution, a high-pressure natural gas is transmitted from the outside to blow the impeller of the second expansion end, and the high-speed rotation of the impeller of the second expansion end drives the rotation of the impeller of the second boosting end, thereby realizing secondary boosting of the natural gas in the outlet pipeline of the reciprocating compressor of the light hydrocarbon recovery device, reducing the pressure at the outlet of the reciprocating compressor, thereby reducing the energy consumption of the reciprocating compressor.

[0015] Optionally, the first boost end pipeline of the first expander extends into the interior of the heat exchange cold box.

[0016] By adopting the above technical solution, the cold energy generated by the expansion of the gas at the second expansion end is exchanged with the newly added heat exchange cold box, thereby reducing the temperature of the natural gas entering the cold box 1 of the light hydrocarbon recovery device and improving the operating efficiency and yield of the light hydrocarbon recovery device.

[0017] Optionally, the second expansion end of the second expander is connected to a heat exchange pipeline, which is relatively connected to the heat exchange cold box. The gas at the second expansion end of the second expander can exchange heat with the gas at the boost end of the first expander inside the heat exchange box.

[0018] Optionally, an air cooler is provided between the first boosting end of the first expander and the heat exchange cold box.

[0019] Optionally, an oil remover is provided between the circulating cooling device and the desulfurization tower.

[0020] In summary, the present application includes at least one of the following beneficial technical effects:

[0021] 1. The power generated by the pressure reduction process of an external high-pressure gas is used to drive the impeller at the second boosting end to achieve secondary boosting of the outlet pressure of the reciprocating compressor of the light hydrocarbon recovery device, which can reduce the outlet pressure of the reciprocating compressor, thereby reducing the energy consumption of the reciprocating compressor. The cooling capacity generated by the second expansion end of the newly added second expander can also be used to reduce the temperature of the raw gas of the light hydrocarbon recovery device, thereby improving the operating efficiency of the light hydrocarbon recovery device.

[0022] 2. The second expander is used to realize secondary pressurization of the natural gas at the outlet of the reciprocating compressor, thereby achieving the purpose of reducing the outlet pressure of the reciprocating compressor.

[0023] 3. A new heat exchange cold box is installed on the inlet pipeline of the raw gas flow channel of the cold box of the light hydrocarbon recovery unit. The cold energy generated during the pressure reduction process of the high-pressure natural gas through the second expansion end of the second expander is used to cool the raw natural gas at the inlet of the cold box, so as to reduce the refrigeration temperature of the device and improve the operating efficiency of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a drawing description of the prior art.

[0025] Figure 2 It is a structural schematic diagram of a device for reducing the energy consumption of a reciprocating compressor of a light hydrocarbon recovery device in an embodiment of the present application.

[0026] Explanation of the reference numerals in the accompanying drawings: 1. Raw gas compressor; 2. Second expansion machine; 21. Second boosting end; 22. Second expansion end; 3. Circulating water cooler; 31. Circulating cooling water inlet; 32. Circulating cooling water outlet; 4. Deoiler; 5. Desulfurization tower; 6. Molecular sieve tower; 7. First expansion machine; 71. First boosting end; 72. First expansion end; 8. Air cooler; 9. Heat exchange cold box; 10. Cold box one. DETAILED DESCRIPTION

[0027] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0028] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0029] The following is combined with Figure 2 This application is described in further detail.

[0030] The present application embodiment discloses a device for reducing the energy consumption of a reciprocating compressor of a light hydrocarbon recovery device. Figure 2 A device for reducing the energy consumption of a reciprocating compressor of a light hydrocarbon recovery device includes a raw gas compressor 1, the gas outlet end of the raw gas compressor 1 is connected to a second expander 2, and the gas outlet end of the raw gas compressor 1 is relatively connected to a second boosting end 21 of the second expander 2, so that the outlet gas of the raw gas compressor 1 enters the second boosting end 21 of the second expander 2.

[0031] The second expansion end 22 of the second expander 2 is connected to high-pressure natural gas, and the high-pressure natural gas blows the impeller of the second expansion end 22 of the second expander 2 to rotate, so that the impeller of the second expansion end 22 rotates at a high speed, driving the impeller of the second boosting end 21 to rotate, so that the gas generated by the raw gas compressor 1 is secondary boosted, reducing the outlet pressure, thereby reducing the energy consumption of the compressor.

[0032] The outlet of the second boosting end 21 of the second expander 2 is connected to a circulating water cooler 3, one end of the circulating water cooler 3 is provided with a circulating cooling water inlet 31, and the other end of the circulating water cooler 3 is provided with a circulating cooling water outlet 32. The boosted gas can be cooled by the circulating water cooler 3, and the cooled gas is then connected to the inlet pipeline of the light hydrocarbon recovery device deoiler 4.

[0033] The light hydrocarbon recovery device oil remover 4 includes an oil remover 4 , the inlet end of the oil remover 4 is relatively connected to the outlet end of the circulating water cooler 3 , so that the natural gas discharged from the outlet end of the circulating water cooler 3 enters the interior of the oil remover 4 .

[0034] The outlet end of the de-oiler 4 is connected to a desulfurization tower 5, and the outlet end of the desulfurization tower 5 is connected to a molecular sieve tower 6, so that the natural gas discharged from the de-oiler 4 can enter the desulfurization tower 5 and the molecular sieve tower 6 in sequence for treatment.

[0035] The outlet end of the molecular sieve tower 6 is connected to the first expansion machine 7, and the first boosting end 71 of the first expansion machine 7 is relatively connected to the outlet end of the molecular sieve tower 6, and the first boosting end 71 of the first expansion machine 7 is also connected to the air cooler 8, so that the natural gas discharged from the molecular sieve tower 6 can enter the interior of the first expansion machine 7 and then enter the air cooler 8.

[0036] A heat exchange cold box 9 is provided between the outlet end of the air cooler 8 and the inlet end of the cold box 10, and the gas discharged from the air cooler 8 can enter the heat exchange cold box 9 through a pipeline.

[0037] The inlet pipeline of the second expansion end 22 of the second expansion machine 2 is connected to the external high-pressure natural gas, and the outlet pipeline of the second expansion end 22 of the second expansion machine 2 extends into the interior of the heat exchange cold box 9 and is connected to the cold box 10, so that the high-pressure natural gas is depressurized by the second expansion machine 2, and the depressurized gas is input from the pipeline into the interior of the heat exchange cold box 9, so that heat exchange is performed inside the heat exchange cold box 9, and the low-pressure and low-temperature natural gas enters the heat exchange cold box 9, exchanges heat with the natural gas at the outlet of the first boosting end 71 of the first expansion machine 7, and enters the downstream low-pressure external transmission pipeline network.

[0038] In the present invention, the term "plurality" means at least two or more than two, unless otherwise clearly defined. The terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0039] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

Claims

1. A device for reducing energy consumption of a reciprocating compressor of a light hydrocarbon recovery device, comprising a raw gas compressor (1), the raw gas compressor (1) being connected to a desulfurization tower (5) and a molecular sieve tower (6), the molecular sieve tower (6) being connected to a first expander (7), one side of the first expander (7) being connected to a cold box (10), characterized in that: A second expander (2) is provided between the raw gas compressor (1) and the desulfurization tower (5); the raw gas compressor (1) and the boosting end of the second expander (2) are relatively connected; and a circulating cooling device is also provided between the raw gas compressor (1) and the desulfurization tower (5).

2. According to claim 1, a device for reducing energy consumption of a reciprocating compressor of a light hydrocarbon recovery device is characterized in that: The circulating cooling device comprises a circulating water cooler (3), one end of the circulating water cooler (3) is provided with a circulating cooling water inlet (31), and the other end of the circulating water cooler (3) is provided with a circulating cooling water outlet (32).

3. The device for reducing energy consumption of a reciprocating compressor of a light hydrocarbon recovery device according to claim 1, characterized in that: A heat exchange cold box (9) is fixedly connected to the raw material gas flow channel inlet pipeline of the cold box one (10), and the heat exchange cold box (9) is relatively connected to the cold box one (10).

4. The device for reducing energy consumption of a reciprocating compressor of a light hydrocarbon recovery device according to claim 3, characterized in that: The second expansion end (22) of the second expansion machine (2) is connected to a high-pressure natural gas inlet, and the high-pressure natural gas inlet can drive the impeller of the second expansion end (22) of the second expansion machine (2) to rotate.

5. The device for reducing energy consumption of a reciprocating compressor of a light hydrocarbon recovery device according to claim 3, characterized in that: The pipeline of the first boosting end (71) of the first expander (7) extends into the interior of the heat exchange cold box (9).

6. The device for reducing energy consumption of a reciprocating compressor of a light hydrocarbon recovery device according to claim 4, characterized in that: The second expansion end (22) of the second expansion machine (2) is connected to a heat exchange pipeline, and the heat exchange pipeline is relatively connected to the heat exchange cold box (9). The gas at the second expansion end (22) of the second expansion machine (2) can exchange heat with the gas at the boost end of the first expansion machine (7) inside the heat exchange cold box (9).

7. The device for reducing energy consumption of a reciprocating compressor of a light hydrocarbon recovery device according to claim 5, characterized in that: An air cooler (8) is provided between the first boosting end (71) of the first expander (7) and the heat exchange cold box (9).

8. The device for reducing energy consumption of a reciprocating compressor of a light hydrocarbon recovery device according to claim 1, characterized in that: An oil remover (4) is provided between the circulating cooling device and the desulfurization tower (5).

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