A heat recovery unit and method for a light hydrocarbon deep recovery system

Abstract

The application provides a light hydrocarbon deep recovery system temperature recovery device and method, which comprises a temperature recovery assembly, wherein the light hydrocarbon deep recovery system is provided with one temperature recovery assembly; the inlet of the temperature recovery assembly is connected with the outlet of an external delivery natural gas compressor on the light hydrocarbon deep recovery system, and the outlet of the temperature recovery assembly is connected with the inlet of a component to be temperature recovered in the light hydrocarbon deep recovery system; the device can solve the temperature recovery difficulty of the light hydrocarbon deep recovery device, so that the natural gas is not vented during the temperature recovery process, air pollution is avoided, and the effects of large temperature recovery gas amount, fast temperature recovery speed and high temperature recovery temperature are achieved.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas field development technology, and particularly relates to a reheating device and method for a light hydrocarbon deep recovery system. Background Technology

[0002] During shutdown and maintenance of light hydrocarbon deep recovery units, a large amount of non-volatile cryogenic liquid hydrocarbons accumulate at low temperatures in the cryogenic towers, packing, equipment, and pipelines. To accelerate the nitrogen purging effect and speed before maintenance, and to prevent freezing blockages and frostbite to personnel during the maintenance process, the containers, equipment, and pipelines must be heated to a higher temperature before maintenance. This forced acceleration of cryogenic liquid hydrocarbon volatilization ensures safety during maintenance and shortens nitrogen purging time. Traditional heating methods are divided into natural heating and forced heating. Small processing units generally use natural heating, while large processing units, due to their large towers, extensive internal packing, large pipeline diameters, and long pipeline distances, mostly use forced heating to save time on heating operations during maintenance.

[0003] Because there is no fixed reheating process for light hydrocarbon recovery units, most oil and gas field light hydrocarbon recovery units currently use a method where the dehydrated feed gas is heated with heat transfer oil and then purged through a low-temperature light hydrocarbon recovery unit. This purging process is done while simultaneously venting the gas to reheat the unit and evaporate the accumulated low-temperature liquid hydrocarbons. However, this reheating method results in significant waste of natural gas and environmental pollution. When using heat transfer oil as the heating medium, the method of simultaneous purging and venting necessitates controlling the feed gas flow rate to improve the reheating effect. A large flow rate makes it difficult to reach the target temperature, and also results in a larger vented natural gas volume. Conversely, a small flow rate makes it difficult to control the heating temperature, increasing operational risks (the cold box requires the medium temperature not to exceed 60 degrees Celsius). Therefore, intermittent heating is necessary, leading to a very slow reheating rate, poor reheating effect, and long recovery time. Summary of the Invention

[0004] The purpose of this invention is to provide a reheating device and method for a light hydrocarbon deep recovery system, which solves the defects of poor reheating effect and long time in existing light hydrocarbon deep recovery device reheating methods.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The present invention provides a reheating device for a light hydrocarbon deep recovery system, comprising a reheating component, wherein the light hydrocarbon deep recovery system is configured with a reheating component; The inlet of the reheating component is connected to the outlet of the natural gas compressor on the light hydrocarbon deep recovery system, and the outlet of the reheating component is connected to the inlet of the component to be reheated in the light hydrocarbon deep recovery system.

[0006] Preferably, the component to be reheated in the light hydrocarbon deep recovery system includes a mercury removal and dehydration device and a light hydrocarbon deep recovery device, wherein the outlet of the reheating component is sequentially connected to the mercury removal and dehydration device and the light hydrocarbon deep recovery device.

[0007] Preferably, the reheating assembly includes an outlet pipeline of an external natural gas compressor and an inlet pipeline of a regenerated gas compressor, wherein the inlet of the external natural gas compressor outlet pipeline is connected to the external natural gas outlet of the light hydrocarbon deep recovery system, and the outlet of the external natural gas compressor outlet pipeline is connected to the inlet of the mercury removal and dehydration device via the regenerated gas compressor inlet pipeline.

[0008] Preferably, the inlet pipeline of the regenerated gas compressor is connected to the inlet of the regenerated gas compressor in the mercury removal and dehydration device.

[0009] Preferably, a flow regulating valve assembly is provided on the inlet pipeline of the regenerated gas compressor.

[0010] Preferably, the inlet of the reheating component is connected to the outlet of the external natural gas compressor in the light hydrocarbon deep recovery system.

[0011] A method for reheating a light hydrocarbon deep recovery device includes the following steps: First, adjust the pressure in the light hydrocarbon deep recovery system to the preset range value; Secondly, the natural gas output from the light hydrocarbon deep recovery system is fed into the reheating component, and the pressure of the natural gas at the outlet of the reheating component is adjusted to the preset range; Finally, the natural gas at the outlet of the reheating component is led to the inlet of the component to be reheated in the light hydrocarbon deep recovery system, thereby achieving the reheating treatment of the light hydrocarbon deep recovery system.

[0012] Preferably, the pressure in the light hydrocarbon deep recovery system is adjusted to a preset range value. Specifically, the method is as follows: The pressure in the light hydrocarbon deep recovery system is reduced to 4.2MPa-4.5MPa by using the vent valve installed at the inlet of the cold box in the light hydrocarbon deep recovery device, and the inlet temperature of the cold box in the light hydrocarbon deep recovery device is greater than or equal to minus 10 degrees Celsius. Gradually open the JT valve to increase the pressure of the DHX tower and the deethaner tower. Use the vent valve at the top of the DHX tower in the light hydrocarbon deep recovery unit to reduce the pressure in the light hydrocarbon deep recovery system to 3.6 MPa-3.8 MPa, and then close the JT valve.

[0013] Preferably, a regenerated gas compressor is used to pressurize the natural gas at the outlet of the reheating unit to 4.0 MPa-4.2 MPa.

[0014] Preferably, during the reheating process, if the pressure in the light hydrocarbon deep recovery system is insufficient, the system is pressurized using natural gas at the inlet of the light hydrocarbon deep recovery system so that the pressure of the light hydrocarbon deep recovery system meets the requirements of 3.6MPa to 3.8MPa.

[0015] Compared with the prior art, the beneficial effects of the present invention are: This invention provides a reheating device for a light hydrocarbon deep recovery system. The reheating component transports natural gas from the system to a mercury removal and dehydration unit for dehydration and heating. The heated natural gas then enters the light hydrocarbon deep recovery unit through the discharge valve of the mercury removal and dehydration unit, reheating various parts of the low-temperature system. Afterward, it is fed into the external natural gas compressor, ultimately forming a closed-loop reheating process to complete the reheating of the light hydrocarbon deep recovery system. This device solves the problem of difficult reheating in light hydrocarbon deep recovery units, ensuring that natural gas is not vented during the reheating process, thus avoiding air pollution. It also achieves the effects of large reheating volume, fast reheating speed, and high reheating temperature. This invention can shorten the reheating time of the light hydrocarbon deep recovery unit before maintenance by more than half, reduce the unit maintenance time by nearly one day, and reduce the natural gas venting by more than 1 million cubic meters. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the reheating device of a light hydrocarbon deep recovery system provided in an embodiment of the present invention; Figure 2 A schematic diagram of the reheating device of a light hydrocarbon deep recovery system provided in another embodiment of the present invention; Figure 3 This is a schematic diagram of the mercury removal and dehydration device structure of the reheating unit of a light hydrocarbon deep recovery system provided in an embodiment of the present invention; Among them, 11 (21) Pipeline cleaning unit; 12 (22) Separation and metering area; 13 (23) Mercury removal and dehydration unit; 14 (24) Light hydrocarbon deep recovery unit; 15 (25) Natural gas compressor for external transmission; 16 (26) Regeneration component; 131, Raw material separator; 132, Raw material gas filter separator; 133, Mercury removal tower; 134, Mercury removal agent dust filter; 135, Molecular sieve dehydration and regeneration unit; 1351, First molecular sieve tower; 1352, Second molecular sieve tower; 1353, Third molecular sieve tower; 1354, Regeneration gas heater; 1355, Regeneration gas Heat exchanger; 1356, regenerated gas air cooler; 1357, regenerated gas separator; 1358 (2358), regenerated gas compressor; 1359 (2359), flow regulating valve assembly; 141 (241), cold box; 142 (242), cryogenic separator; 143 (243), expander; 144 (244), DHX tower; 145 (245), deethaner; 146 (246), inlet vent valve; 161 (261), outlet pipeline of natural gas compressor; 162 (262), inlet pipeline of regenerated gas compressor; 147 (247), JT valve. Detailed Implementation

[0017] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0018] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0019] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0020] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrases "if determined" or "if detected [the described condition or event]" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once detected [the described condition or event]," or "in response to detection [the described condition or event]."

[0021] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0022] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0023] Example 1 See appendix Figure 1 This embodiment provides a reheating device for a light hydrocarbon deep recovery system, including a reheating component, wherein the light hydrocarbon deep recovery system is equipped with a reheating component; The inlet of the reheating component is connected to the natural gas outlet of the light hydrocarbon deep recovery system, and the outlet of the reheating component is connected to the inlet of the component to be reheated in the light hydrocarbon deep recovery system.

[0024] Example 2 This embodiment provides a reheating device for a light hydrocarbon deep recovery system, including a reheating component, wherein the light hydrocarbon deep recovery system is equipped with a reheating component; The inlet of the reheating component is connected to the natural gas outlet of the light hydrocarbon deep recovery system, and the outlet of the reheating component is connected to the inlet of the component to be reheated in the light hydrocarbon deep recovery system.

[0025] The light hydrocarbon deep recovery system includes a pigging device 11, a separation and metering zone 12, a mercury removal and dehydration device 13, a light hydrocarbon deep recovery device 14, an external natural gas compressor 15, and an external downstream pipeline network, all connected in sequence.

[0026] The outlet of the natural gas compressor 15 is provided with a bypass, which is connected to the inlet of the reheating component, and the outlet of the reheating component is connected to the inlet of the mercury removal and dehydration device 13.

[0027] Example 3 This embodiment provides a reheating device for a light hydrocarbon deep recovery system, including a reheating component, wherein the light hydrocarbon deep recovery system is equipped with a reheating component; The inlet of the reheating component is connected to the natural gas outlet of the light hydrocarbon deep recovery system, and the outlet of the reheating component is connected to the inlet of the component to be reheated in the light hydrocarbon deep recovery system.

[0028] The light hydrocarbon deep recovery system includes a pigging device 11, a separation and metering zone 12, a mercury removal and dehydration device 13, a light hydrocarbon deep recovery device 14, an external natural gas compressor 15, and an external downstream pipeline network, all connected in sequence.

[0029] The outlet of the natural gas compressor 15 is provided with a bypass, which is connected to the inlet of the reheating component, and the outlet of the reheating component is connected to the inlet of the mercury removal and dehydration device 13.

[0030] The reheating assembly 16 includes an outlet pipeline 161 of the external natural gas compressor and an inlet pipeline 162 of the regenerated gas compressor. The outlet pipeline 161 of the external natural gas compressor is connected to a bypass, and the outlet pipeline 161 of the external natural gas compressor is connected to the inlet of the mercury removal and dehydration device 13 via the inlet pipeline 162 of the regenerated gas compressor.

[0031] Example 4 This embodiment provides a reheating device for a light hydrocarbon deep recovery system, including a reheating component, wherein the light hydrocarbon deep recovery system is equipped with a reheating component; The inlet of the reheating component is connected to the natural gas outlet of the light hydrocarbon deep recovery system, and the outlet of the reheating component is connected to the inlet of the component to be reheated in the light hydrocarbon deep recovery system.

[0032] The light hydrocarbon deep recovery system includes a pigging device 11, a separation and metering zone 12, a mercury removal and dehydration device 13, a light hydrocarbon deep recovery device 14, an external natural gas compressor 15, and an external downstream pipeline network, all connected in sequence.

[0033] The outlet of the natural gas compressor 15 is provided with a bypass, which is connected to the inlet of the reheating component, and the outlet of the reheating component is connected to the inlet of the mercury removal and dehydration device 13.

[0034] like Figure 3As shown, the mercury removal and dehydration device 13 includes at least a raw material separator 131, a raw material gas filter separator 132, a mercury removal tower 133, a mercury removal agent dust filter 134, and a molecular sieve dehydration and regeneration device 135 connected in sequence.

[0035] The molecular sieve dehydration and regeneration device 135 includes a molecular sieve tower, a regeneration gas heater 1354, a regeneration gas heat exchanger 1355, a regeneration gas air cooler 1356, a regeneration gas separator 1357, and a regeneration gas compressor 1358 connected in sequence.

[0036] The molecular sieve tower includes a first molecular sieve tower 1351, a second molecular sieve tower 1352, and a third molecular sieve tower 1353. Natural gas can be dehydrated through one of the first molecular sieve tower 1351, the second molecular sieve tower 1352, and the third molecular sieve tower 1353, which can improve the efficiency of dehydration treatment.

[0037] The working process of the mercury removal and dehydration device in this embodiment is as follows: Natural gas is pretreated by a raw material separator 131, a raw material gas filter separator 132, a mercury removal tower 133, and a mercury removal agent dust filter 134 before entering a molecular sieve dehydration and regeneration unit 135. A regeneration gas heater 1354 and a regeneration gas air cooler 1356 are used to regulate the temperature of the natural gas. The natural gas undergoes dehydration treatment in the molecular sieve tower and then enters the regeneration gas heater 1354 for heating. The regeneration gas heater 1354 is also connected to a heat source inlet pipeline and a heat source outlet pipeline. The heat source can be heat transfer oil. The heat transfer oil heats the natural gas via the heat source inlet pipeline, the regeneration gas heater, and the heat source outlet pipeline. The natural gas then enters the light hydrocarbon deep recovery unit via the regeneration gas heat exchanger 1355 and the outlet valve.

[0038] Example 5 This embodiment provides a reheating device for a light hydrocarbon deep recovery system, including a reheating component, wherein the light hydrocarbon deep recovery system is equipped with a reheating component; The inlet of the reheating component is connected to the natural gas outlet of the light hydrocarbon deep recovery system, and the outlet of the reheating component is connected to the inlet of the component to be reheated in the light hydrocarbon deep recovery system.

[0039] The light hydrocarbon deep recovery system includes a pigging device 11, a separation and metering zone 12, a mercury removal and dehydration device 13, a light hydrocarbon deep recovery device 14, an external natural gas compressor 15, and an external downstream pipeline network, all connected in sequence.

[0040] The outlet of the natural gas compressor 15 is provided with a bypass, which is connected to the inlet of the reheating component, and the outlet of the reheating component is connected to the inlet of the mercury removal and dehydration device 13.

[0041] The light hydrocarbon deep recovery unit 14 includes at least a cold box 141, a cryogenic separator 142, an expander 143, a DHX tower 144, and a deethanizer 145. The outlet of the cold box 141 is connected to the inlet of the cryogenic separator 142. The top outlet of the cryogenic separator 142 is divided into two paths: one connected to the inlet of the expander 143, and the other connected to the inlet of the DHX tower 144. The expander 143 is also connected to the inlet of the DHX tower 144. The top outlet of the DHX tower 144 is connected to the inlet of the expander 143. The bottom outlet of the DHX tower 144 is connected to the inlet of the deethanizer 145 via the cold box 141. The bottom outlet of the cryogenic separator 142 is connected to the inlet of the deethanizer 145 via the cold box 141, and the outlet of the deethanizer 145 is connected to the inlet of the DHX tower 144 via the cold box 141.

[0042] An inlet vent valve 146 is provided at the inlet of the cold box 141.

[0043] A JT valve 147 is installed at the inlet of the DHX tower 144. Pipelines 142 and 144 are directly connected. Example 6 The reheating method for a light hydrocarbon deep recovery device proposed in this embodiment includes the following steps: After the light hydrocarbon deep recovery system is shut down, firstly, the pressure of the low-temperature system of the mercury removal and dehydration unit 13 and the light hydrocarbon deep recovery unit 14 is reduced to 4.2MPa-4.5MPa through the inlet vent valve 146 of the light hydrocarbon deep recovery unit, and it is important to note that the inlet temperature of the cold box 141 must not be lower than -10 degrees Celsius. Next, gradually open JT valve 147 to increase the pressure of DHX tower 144 and deethaner 145. Adjust the overall system pressure to 3.6 MPa-3.8 MPa through the vent valve at the top of DHX tower 144, and then close JT valve 147.

[0044] Next, ensure that the processes of the mercury removal and dehydration unit 13, the light hydrocarbon deep recovery unit 14, and the external natural gas compressor 15 are connected.

[0045] Finally, start the regeneration gas compressor 1358 to establish the reheat cycle of the light hydrocarbon deep recovery system. The specific cycle process is as follows: Natural gas in the system enters the regenerator 1358 through the discharge valve at the outlet of the external natural gas compressor 15, via the external natural gas compressor outlet pipeline 161 and the regenerator inlet pipeline 162. The natural gas is then pressurized to 4.0 MPa-4.2 MPa by the regenerator 1358. The pressure is adjusted to 36,000 Nm3 / hour to 38,000 Nm3 / hour via the pipeline at the outlet of the regenerated gas compressor and the outlet regulating valve at the outlet. Then, it enters the mercury removal and dehydration unit 13 for dehydration and heating. After heating, the natural gas enters the light hydrocarbon deep recovery unit through the discharge valve of the mercury removal and dehydration unit 13 to reheat the various parts of the low-temperature system. After being reheated through the cold box 141, low-temperature separator 142, expander 143, DHX tower 144, and deethaner 145, the natural gas enters the regenerated gas compressor 1358 through the external natural gas compressor 15, the external natural gas compressor outlet pipeline 161, and the regenerated gas compressor inlet pipeline 162, finally forming a closed-loop reheating process to complete the reheating of the light hydrocarbon deep recovery system.

[0046] During the reheating process, if the system pressure is insufficient, the system can be pressurized through the natural gas inlet valve 111 at the front end of the pigging device 11 and the natural gas inlet valve 121 after the separation metering zone 1212 to maintain the system within the range of 3.6MPa to 3.8MPa.

[0047] In this recirculation process, the heat source flow rate of the regenerated gas heater 1354 is adjusted to control the temperature of the regenerated gas air cooler 1356 to be no higher than 100℃. The regenerated gas air cooler 1356 is adjusted to control the inlet temperature of the regenerated gas compressor 1358 within the range of 55℃ to 60℃, so that the outlet temperature of the regenerated gas compressor 1358 can be controlled within the range of 60℃ to 70℃.

[0048] Example 7 like Figure 2 As shown in the figure, this embodiment provides a reheating device for a light hydrocarbon deep recovery system. The light hydrocarbon deep recovery system is provided in two rows, and each row of light hydrocarbon deep recovery system is equipped with a reheating component. The inlet of the reheating component is connected to the natural gas outlet of the light hydrocarbon deep recovery system, and the outlet of the reheating component is connected to the inlet of the component to be reheated in the light hydrocarbon deep recovery system.

[0049] The two light hydrocarbon deep recovery systems are connected by a connecting component 3.

[0050] Example 8 This embodiment provides a reheating device for a light hydrocarbon deep recovery system. The light hydrocarbon deep recovery system is provided in two rows, and each row of the light hydrocarbon deep recovery system is equipped with a reheating component. The inlet of the reheating component is connected to the natural gas outlet of the light hydrocarbon deep recovery system, and the outlet of the reheating component is connected to the inlet of the component to be reheated in the light hydrocarbon deep recovery system.

[0051] The two light hydrocarbon deep recovery systems are connected by a connecting component 3.

[0052] The connecting component 3 includes a connecting pipeline 31, the two ends of which are respectively installed between the light hydrocarbon deep recovery device and the external natural gas compressor in the two light hydrocarbon deep recovery systems.

[0053] A valve 32 is installed on the connecting pipeline 31.

[0054] The working process of this embodiment: Two light hydrocarbon deep recovery systems can be connected by the connecting component 3. The two light hydrocarbon deep recovery systems can be the first light hydrocarbon deep recovery system 1 and the second light hydrocarbon deep recovery system 2. The first light hydrocarbon deep recovery system 1 forms a closed-loop reheating process. After the natural gas from the second light hydrocarbon deep recovery system 2 is reheated by the light hydrocarbon deep recovery device 24, it can enter the external natural gas compressor 15 of the first light hydrocarbon deep recovery system through the connecting component 3, and finally enter the reheating system 26 of the second light hydrocarbon deep recovery system 2 through the reheating connection pipeline, forming a complete closed-loop reheating process and completing the reheating of the second light hydrocarbon deep recovery system.

[0055] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method for reheating a light hydrocarbon deep recovery system, the light hydrocarbon deep recovery system comprising a mercury removal and dehydration unit (13), a light hydrocarbon deep recovery unit (14), and an external natural gas compressor (15) connected in sequence, wherein the light hydrocarbon deep recovery unit (14) comprises at least a cold box (141), a cryogenic separator (142), an expander (143), a DHX tower (144), and an ethane removal tower (145), wherein, The outlet of the cold box (141) is connected to the inlet of the cryogenic separator (142). The top outlet of the cryogenic separator (142) is divided into two paths: one path goes through the expander (143) and connects to the inlet of the DHX tower (144), and the other path goes through the JT valve (147) and connects to the inlet of the DHX tower (144). The top outlet of the DHX tower (144) is connected to the inlet of the expander (143), and the bottom outlet of the DHX tower (144) goes through the cold box (141) and connects to the inlet of the deethaner (145). The bottom outlet of the cryogenic separator (142) goes through the cold box (141) and connects to the inlet of the deethaner (145). The outlet of the deethaner (145) goes through the cold box (141) and connects to the inlet of the DHX tower (144). The outlet of the expander (143) is connected to the external natural gas compressor (15). The characteristic feature is that the temperature recovery method includes the following steps: First, adjust the pressure in the light hydrocarbon deep recovery system to the preset range value; Secondly, the natural gas output from the light hydrocarbon deep recovery system is fed into the reheating component, and the pressure of the natural gas at the outlet of the reheating component is adjusted to the preset range; Finally, the natural gas at the outlet of the reheating component is led to the mercury removal and dehydration unit in the light hydrocarbon deep recovery system for dehydration and heating, thereby achieving the reheating treatment of the light hydrocarbon deep recovery system; then it is fed into the external natural gas compressor to form a closed-loop reheating process. Adjusting the pressure in the light hydrocarbon deep recovery system to the preset range is done as follows: The pressure in the light hydrocarbon deep recovery system is reduced to 4.2MPa-4.5MPa by using the vent valve installed at the inlet of the cold box in the light hydrocarbon deep recovery device, and the inlet temperature of the cold box in the light hydrocarbon deep recovery device is greater than or equal to minus 10 degrees Celsius. Gradually open the JT valve (147) set at the inlet of the DHX tower (144) to increase the pressure of the DHX tower (144) and the deethaner tower (145). Use the vent valve set at the top of the DHX tower (144) in the light hydrocarbon deep recovery unit to reduce the pressure in the light hydrocarbon deep recovery system to 3.6 MPa-3.8 MPa, and close the JT valve (147).

2. The temperature recovery method for a light hydrocarbon deep recovery system according to claim 1, characterized in that, At the outlet of the regenerated gas unit, a regenerated gas compressor (1358) is used to boost the pressure of natural gas to 4.0 MPa-4.2 MPa.

3. The temperature recovery method for a light hydrocarbon deep recovery system according to claim 1, characterized in that, During the reheating process, if the pressure in the light hydrocarbon deep recovery system is insufficient, the system is pressurized using natural gas at the inlet to ensure that the pressure of the light hydrocarbon deep recovery system meets the requirements of 3.6MPa to 3.8MPa.

4. The temperature recovery method for a light hydrocarbon deep recovery system according to claim 1, characterized in that, The inlet of the reheating component is connected to the outlet of the natural gas compressor on the light hydrocarbon deep recovery system.

5. The temperature recovery method for a light hydrocarbon deep recovery system according to claim 1, characterized in that, The regeneration assembly includes an outlet pipeline (161) for the external natural gas compressor and an inlet pipeline (162) for the regenerated gas compressor. The inlet of the outlet pipeline (161) for the external natural gas compressor is connected to the outlet of the external natural gas on the light hydrocarbon deep recovery system, and the outlet of the outlet pipeline (161) for the external natural gas compressor is connected to the inlet of the mercury removal and dehydration device (13) via the inlet pipeline (162) for the regenerated gas compressor.

6. The temperature recovery method for a light hydrocarbon deep recovery system according to claim 5, characterized in that, The inlet pipeline (162) of the regenerated gas compressor is connected to the inlet of the regenerated gas compressor (1358) in the mercury removal and dehydration device (13).

7. The temperature recovery method for a light hydrocarbon deep recovery system according to claim 5, characterized in that, A flow regulating valve assembly is installed on the inlet pipeline (162) of the regenerated gas compressor.

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