Light hydrocarbon separation combined with cold energy power generation system

Abstract

The application discloses a light hydrocarbon separation and cold energy power generation combined system, which comprises a separation tank, a heat exchange flow channel of the separation tank, a conveying pipeline, a separation gas pipeline, a light hydrocarbon product pipeline and a cold energy power generation unit, wherein the heat exchange flow channel is capable of exchanging heat with the tank body shell of the separation tank; the outlet of the conveying pipeline is communicated with the inlet of the separation tank; the inlet of the separation gas pipeline is communicated with the gas outlet of the separation tank; the inlet of the light hydrocarbon product pipeline is communicated with the material outlet of the separation tank; the high-temperature working medium outlet of the cold energy power generation unit is communicated with the inlet end of the heat exchange flow channel, and the outlet end of the heat exchange flow channel is communicated with the low-temperature working medium inlet of the cold energy power generation unit. The light hydrocarbon separation and cold energy power generation combined system provided by the application improves the efficiency of light hydrocarbon separation.

Description

Technical Field

[0001] This invention relates to the field of power generation equipment technology, and in particular to a combined system for light hydrocarbon separation and cold energy power generation. Background Technology

[0002] LNG (liquefied natural gas) is natural gas that exists in a liquid form at low temperatures and usually needs to be regasified before it can be used. The cold energy released during LNG regasification is approximately 840 kJ / kg, and recovering this energy has considerable economic and social benefits.

[0003] Currently, much of the LNG traded globally is in the form of wet gases (ethane, propane, etc.). (The molar content of light hydrocarbons is above 10%), in moisture Light hydrocarbons are high-quality and clean feedstock for ethylene cracking. Using them to replace naphtha in ethylene production can save 30% on plant investment, reduce energy consumption by 30%, and lower overall costs by 10%. Utilizing the cold energy of LNG to separate light hydrocarbon resources can also eliminate the need for refrigeration equipment, obtaining high-value-added ethane and other hydrocarbons with very low energy consumption. The combination of liquefied petroleum gas (LPG) and LNG vaporization is an effective way to utilize LNG cold energy.

[0004] In the separation system, deethaners and demethanizers are generally used to separate light hydrocarbons. The temperature of the reboiler in the demethanizer is about 50 to 70°C, and its heat consumption can be provided by the combustion of natural gas after the light hydrocarbon separation. The cooling capacity required for the condenser in the deethaner is provided by LNG, and the temperature of the reboiler is about -20 to -35°C, which can be directly heated by air or water.

[0005] Currently, systems combining light hydrocarbon separation units and cold energy power generation primarily utilize cold energy before LNG enters the separation tower. This combined process, which utilizes cold energy before LNG enters the separation tower, can impact the operation of separation tanks such as flash tanks. To maintain certain parameters in these tanks, adjustments to the operating conditions of the cold energy power generation system are necessary. Since the temperature control module (LNG cold energy power generation system) is separate from the light hydrocarbon separation unit, system adjustments are delayed and more complex. Furthermore, the separation of the heat exchange and flash processes negatively affects the light hydrocarbon separation efficiency, thus impacting the overall light hydrocarbon separation process.

[0006] Therefore, how to improve the efficiency of light hydrocarbon separation is a problem that urgently needs to be solved by those in this technical field. Summary of the Invention

[0007] In view of this, the present invention provides a combined system for light hydrocarbon separation and cold energy power generation to improve the efficiency of light hydrocarbon separation.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A combined system for light hydrocarbon separation and cold energy power generation, comprising:

[0010] A separation tank having a heat exchange channel capable of exchanging heat with its outer shell;

[0011] A conveying pipeline, the outlet of which is connected to the inlet of the separation tank;

[0012] A gas separation pipeline, the inlet of which is connected to the gas outlet of the separation tank;

[0013] A light hydrocarbon product pipeline, the inlet of which is connected to the material outlet of the separation tank;

[0014] A cold-energy generator set, wherein the high-temperature working fluid outlet of the cold-energy generator set is connected to the inlet end of the heat exchange channel, and the outlet end of the heat exchange channel is connected to the low-temperature working fluid inlet of the cold-energy generator set.

[0015] Optionally, in the above-mentioned light hydrocarbon separation and cold energy power generation combined system, the power generation working fluid of the cold energy generator unit flows from the low-temperature working fluid inlet to the high-temperature working fluid outlet.

[0016] Optionally, in the above-mentioned light hydrocarbon separation and cold energy power generation combined system, the separation tank includes a flash tank and a demethanizing tank;

[0017] The outlet of the conveying pipeline is connected to the flash inlet of the flash tank, the material outlet of the flash tank is connected to the separation inlet of the demethanizing tank, and the material outlet of the demethanizing tank is connected to the inlet of the light hydrocarbon product pipeline.

[0018] Optionally, in the above-mentioned light hydrocarbon separation and cold energy power generation combined system, the flash tank has a first heat exchange channel that can exchange heat with its outer shell;

[0019] The demethanizing tank has a second heat exchange channel that can exchange heat with its outer shell.

[0020] The high-temperature working fluid outlet of the cold energy generator set is connected to the inlet end of the first heat exchange channel and the second heat exchange channel, and the low-temperature working fluid inlet of the cold energy generator set is connected to the outlet end of the first heat exchange channel and the second heat exchange channel.

[0021] Optionally, in the above-mentioned light hydrocarbon separation and cold energy power generation combined system, the cold energy generator set includes a first cold energy generator set and a second cold energy generator set.

[0022] The high-temperature working fluid outlet of the first cold energy generator set is connected to the inlet end of the first heat exchange channel through a first high-temperature working fluid pipeline, and the low-temperature working fluid inlet of the first cold energy generator set is connected to the outlet end of the second heat exchange channel through a first low-temperature working fluid pipeline.

[0023] The high-temperature working fluid outlet of the second cold energy generator set is connected to the inlet end of the second heat exchange channel through a second high-temperature working fluid pipeline, and the low-temperature working fluid inlet of the second cold energy generator set is connected to the outlet end of the second heat exchange channel through a second low-temperature working fluid pipeline.

[0024] Optionally, in the above-mentioned light hydrocarbon separation and cold energy power generation combined system, the outer shell of the separation tank has a double-layered cavity, and the double-layered cavity has the heat exchange channel.

[0025] Optionally, the above-mentioned light hydrocarbon separation and cold energy power generation combined system also includes an auxiliary pipeline connecting the high-temperature working fluid outlet and the low-temperature working fluid inlet.

[0026] Optionally, the above-mentioned light hydrocarbon separation and cold energy power generation combined system also includes a first booster pump and a supply pipeline for connecting to the outlet of the LING storage tank.

[0027] The inlet of the first booster pump is connected to the outlet of the supply pipeline, and the outlet of the first booster pump is connected to the delivery pipeline.

[0028] Optionally, the above-mentioned light hydrocarbon separation and cold energy power generation combined system also includes a second booster pump and a methane delivery pipeline;

[0029] The inlet of the second booster pump is connected to the outlet of the separated gas pipeline, and the outlet of the second booster pump is connected to the methane delivery pipeline.

[0030] Optionally, in the above-mentioned light hydrocarbon separation and cold energy power generation combined system, a heater and a working fluid booster pump are connected in series on the low-temperature working fluid pipeline connecting the outlet end of the heat exchange channel and the low-temperature working fluid inlet of the cold energy generator set.

[0031] As can be seen from the above technical solution, the light hydrocarbon separation and cold energy power generation combined system provided by the present invention heats the outer shell of the separation tank by using the working fluid of the cold energy generator set, ensuring the stable operation of the separation tank. It eliminates the need for the temperature control module in the entire system to adjust the operating temperature of the separation tank, making it convenient to control the temperature change during the use of the separation tank, improving the response speed of temperature regulation, and thus improving the efficiency of light hydrocarbon separation. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the structure of the light hydrocarbon separation and cold energy power generation combined system provided in an embodiment of the present invention. Detailed Implementation

[0034] This invention discloses a combined system for light hydrocarbon separation and cold energy power generation to improve the efficiency of light hydrocarbon separation.

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] like Figure 1 As shown, this embodiment of the invention provides a combined system for light hydrocarbon separation and cold energy power generation, including a separation tank, a conveying pipeline 3, a separation gas pipeline, a light hydrocarbon product pipeline 18, and a cold energy generator set.

[0037] The separator has a heat exchange channel that can exchange heat with its outer shell; the outlet of the conveying pipe 3 is connected to the inlet of the separator; the inlet of the separated gas pipe is connected to the gas outlet of the separator; the inlet of the light hydrocarbon product pipe 18 is connected to the material outlet of the separator; the high-temperature working fluid outlet of the cold energy generator set is connected to the inlet end of the heat exchange channel, and the outlet end of the heat exchange channel is connected to the low-temperature working fluid inlet of the cold energy generator set.

[0038] The light hydrocarbon separation and cold energy power generation combined system provided in this embodiment of the invention heats the outer shell of the separation tank by using the working fluid of the cold energy generator set, ensuring the stable operation of the separation tank. It eliminates the need for a temperature control module in the entire system to adjust the operating temperature of the separation tank, making it convenient to control the temperature changes during the use of the separation tank, improving the response speed of temperature regulation, and thus improving the efficiency of light hydrocarbon separation.

[0039] Preferably, the working fluid of the cold-energy generator set flows from the low-temperature working fluid inlet to the high-temperature working fluid outlet. That is, the working fluid is cooled in the heat exchange channel of the separator and then re-enters the cold-energy power generation system. During this process, the separator absorbs heat from the working fluid, completing the separation operation.

[0040] Of course, a heat exchanger can also be installed to exchange heat with the cold energy generator set, and the heat exchange working medium in the heat exchanger can be used as the working medium flowing into the heat exchange channel of the separator.

[0041] In the light hydrocarbon separation and cold energy power generation combined system provided in this embodiment of the invention, the separation tank includes a flash tank 5 and a demethanizing tank 11; the outlet of the conveying pipeline 3 is connected to the flash inlet of the flash tank 5, the material outlet of the flash tank 5 is connected to the separation inlet of the demethanizing tank 11, and the material outlet of the demethanizing tank 11 is connected to the inlet of the light hydrocarbon product pipeline 18.

[0042] That is, flash tank 5 is connected in series with demethanizing tank 11. The substance to be separated (LNG) enters flash tank 5 through pipeline 3 for initial separation; after flashing in flash tank 5, it becomes rich in... Light hydrocarbons are fed into the demethanizing tank 11 through the intermediate pipe 6 for methane removal.

[0043] The substance transported by intermediate pipeline 6 is rich in... Light hydrocarbons.

[0044] Of course, you can also set up only flash tank 5 or demethanizer 11, or even deethaner, etc.

[0045] Furthermore, the flash tank 5 has a first heat exchange channel 4 that can exchange heat with its outer shell; the demethanizer 11 has a second heat exchange channel 12 that can exchange heat with its outer shell.

[0046] The high-temperature working fluid outlet of the cold energy generator set is connected to the inlet end of the first heat exchange channel 4 and the second heat exchange channel 12, and the low-temperature working fluid inlet of the cold energy generator set is connected to the outlet end of the first heat exchange channel 4 and the second heat exchange channel 12.

[0047] With the above setup, the substance to be separated (LNG) enters the flash tank 5 through the transport pipeline 3 for initial separation. During the flash separation process, heat energy (heat from the power generation working fluid) is provided by the working fluid flowing out of the high-temperature working fluid outlet of the cold energy generator set. After flash separation occurs in the flash tank 5, the LNG-rich liquid is transported through the intermediate pipeline 6. Light hydrocarbons are fed into demethanizing tank 11 for methane removal. Light hydrocarbon products are removed through the demethanizing tank 11. The heat required during the methane removal process is provided by the working fluid flowing out from the high-temperature working fluid outlet (heat in the power generation working fluid).

[0048] To further facilitate control, the cold energy generator set includes a first cold energy generator set 20 and a second cold energy generator set 14.

[0049] The high-temperature working fluid outlet of the first cold energy generator set 20 is connected to the inlet end of the first heat exchange channel 4 through the first high-temperature working fluid pipe 19, and the low-temperature working fluid inlet of the first cold energy generator set 20 is connected to the outlet end of the second heat exchange channel 12 through the first low-temperature working fluid pipe 23.

[0050] The high-temperature working fluid outlet of the second cold energy generator set 14 is connected to the inlet end of the second heat exchange channel 12 through the second high-temperature working fluid pipe 13, and the low-temperature working fluid inlet of the second cold energy generator set 14 is connected to the outlet end of the second heat exchange channel 12 through the second low-temperature working fluid pipe 17.

[0051] That is, the flash tank 5 and the demethanizer 11 have relatively independent cold energy generator sets that provide heat energy.

[0052] Preferably, the first cold energy generator set 20 and the second cold energy generator set 14 are turbine generator sets. Of course, other types of generators can also be selected, and no specific restrictions are imposed here, all of which are within the scope of protection.

[0053] Specifically, the power generation medium of the first cold energy generator set 20 flows from the high temperature medium outlet into the inlet end of the first heat exchange channel 4 through the first high temperature medium pipe 19. After being cooled in the first heat exchange channel 4, the power generation medium re-enters the first cold energy generator set 20 through the first low temperature medium pipe 23 from the low temperature medium inlet.

[0054] Similarly, the power generation medium of the second cold energy generator set 14 flows from the high temperature medium outlet into the inlet end of the second heat exchange channel 12 through the second high temperature medium pipe 13. After being cooled in the second heat exchange channel 12, the power generation medium re-enters the second cold energy generator set 14 through the second low temperature medium pipe 17 from the low temperature medium inlet.

[0055] Furthermore, the separator has a double-layered cavity inside its outer shell, and the double-layered cavity has heat exchange channels.

[0056] Specifically, the flash tank 5 has a first interlayer cavity inside its outer shell, and the first interlayer cavity has a first heat exchange channel 4. The demethanizer 11 has a second interlayer cavity inside its outer shell, and the second interlayer cavity has a second heat exchange channel 12.

[0057] The first heat exchange channel 4 and the second heat exchange channel 12 can be internal channels of the heat exchange pipe or channels directly machined inside the outer shell of the tank.

[0058] The light hydrocarbon separation and cold energy power generation combined system provided in this embodiment of the invention also includes an auxiliary pipeline connecting the high-temperature working fluid outlet and the low-temperature working fluid inlet.

[0059] The amount of working fluid flowing into the heat exchange channel can be controlled by adjusting the opening and closing of the auxiliary pipes and the fluid flow rate, thus facilitating specific adjustments based on actual needs.

[0060] The light hydrocarbon separation and cold energy power generation combined system provided in this embodiment of the invention also includes a first booster pump 2 and a supply pipeline 1 for connecting to the outlet of the LING storage tank; the inlet of the first booster pump 2 is connected to the outlet of the supply pipeline 1, and the outlet of the first booster pump 2 is connected to the delivery pipeline 3. Specifically, the substance to be separated (LNG) enters the first booster pump 2 through the supply pipeline 1 from the outlet of the LING storage tank for pressurization, and after pressurization, it enters the separation tank (flash tank 5) through the delivery pipeline 3 for separation.

[0061] Of course, the first booster pump 2 can be omitted, and the output fluid can be pressurized directly through external equipment (LING storage tank).

[0062] Furthermore, the light hydrocarbon separation and cold energy power generation combined system also includes a second booster pump 9 and a methane delivery pipeline 10; the inlet of the second booster pump 9 is connected to the outlet of the separated gas pipeline, and the outlet of the second booster pump 9 is connected to the methane delivery pipeline 10.

[0063] The gas separated in the separator is transported from the separator's gas outlet to the second booster pump 9 for pressurization via the gas separation pipeline, and then enters the methane delivery pipeline 10 for delivery to subsequent processes, such as storage in appropriate containers.

[0064] Specifically, the gas separation pipeline includes a first methane pipeline 8 and a second methane pipeline 7. The gas outlet of the flash tank 5 is connected to the inlet of the first methane pipeline 8, and the gas outlet of the demethanizer 11 is connected to the inlet of the second methane pipeline 7.

[0065] Preferably, the methane from the first methane pipeline 8 and the second methane pipeline 7 are mixed and then enter the second booster pump 9, and finally enter the methane delivery pipeline 10 after being pressurized.

[0066] In this embodiment, a heater and a working fluid booster pump are connected in series on the low-temperature working fluid pipeline connecting the outlet end of the heat exchange channel and the low-temperature working fluid inlet of the cold energy generator set. The heater heats the working fluid flowing back to the cold energy generator set, preventing it from being too cold and affecting the operation of the cold energy generator set; furthermore, the working fluid booster pump pressurizes the working fluid flowing back to the cold energy generator set. These features further ensure the temperature operation of the cold energy generator set.

[0067] In this embodiment, a first heater 21 and a first working fluid booster pump 22 are connected in series on the first cryogenic working fluid pipeline 23; a second heater 15 and a second working fluid booster pump 16 are connected in series on the second cryogenic working fluid pipeline 17.

[0068] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0069] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A combined system for light hydrocarbon separation and cold energy power generation, characterized in that, include: A separation tank having a heat exchange channel capable of exchanging heat with its outer shell; The outlet of the conveying pipeline (3) is connected to the inlet of the separation tank; A gas separation pipeline, the inlet of which is connected to the gas outlet of the separation tank; A light hydrocarbon product pipeline (18) is connected at its inlet to the material outlet of the separator. A cold energy generator set, wherein the high-temperature working fluid outlet of the cold energy generator set is connected to the inlet end of the heat exchange channel, and the outlet end of the heat exchange channel is connected to the low-temperature working fluid inlet of the cold energy generator set. in, The separation tank includes a flash tank (5) and a demethanizing tank (11); the outlet of the conveying pipeline (3) is connected to the flash inlet of the flash tank (5), the material outlet of the flash tank (5) is connected to the separation inlet of the demethanizing tank (11), and the material outlet of the demethanizing tank (11) is connected to the inlet of the light hydrocarbon product pipeline (18). A heater and a working fluid booster pump are connected in series on the low-temperature working fluid pipeline connecting the outlet end of the heat exchange channel and the low-temperature working fluid inlet of the cold energy generator set.

2. The light hydrocarbon separation and cold energy power generation combined system as described in claim 1, characterized in that, The power generation medium of the cold energy generator unit flows from the low-temperature working medium inlet to the high-temperature working medium outlet.

3. The light hydrocarbon separation and cold energy power generation combined system as described in claim 1, characterized in that, The flash tank (5) has a first heat exchange channel (4) that can exchange heat with its outer shell. The demethanizing tank (11) has a second heat exchange channel (12) that can exchange heat with its outer shell. The high-temperature working fluid outlet of the cold energy generator set is connected to the inlet end of the first heat exchange channel (4) and the second heat exchange channel (12), and the low-temperature working fluid inlet of the cold energy generator set is connected to the outlet end of the first heat exchange channel (4) and the second heat exchange channel (12).

4. The light hydrocarbon separation and cold energy power generation combined system as described in claim 3, characterized in that, The cold energy generator set includes a first cold energy generator set (20) and a second cold energy generator set (14). The high-temperature working fluid outlet of the first cold energy generator set (20) is connected to the inlet end of the first heat exchange channel (4) through the first high-temperature working fluid pipeline (19), and the low-temperature working fluid inlet of the first cold energy generator set (20) is connected to the outlet end of the second heat exchange channel (12) through the first low-temperature working fluid pipeline (23). The high-temperature working fluid outlet of the second cold energy generator set (14) is connected to the inlet end of the second heat exchange channel (12) through the second high-temperature working fluid pipeline (13), and the low-temperature working fluid inlet of the second cold energy generator set (14) is connected to the outlet end of the second heat exchange channel (12) through the second low-temperature working fluid pipeline (17).

5. The light hydrocarbon separation and cold energy power generation combined system as described in any one of claims 1-4, characterized in that, The separator has a double-layered cavity inside its outer shell, and the double-layered cavity has the heat exchange channel.

6. The light hydrocarbon separation and cold energy power generation combined system as described in claim 1, characterized in that, It also includes an auxiliary pipeline connecting the high-temperature working medium outlet and the low-temperature working medium inlet.

7. The light hydrocarbon separation and cold energy power generation combined system as described in claim 1, characterized in that, It also includes a first booster pump (2) and a supply pipe (1) for connecting to the outlet of the LING tank. The inlet of the first booster pump (2) is connected to the outlet of the supply pipe (1), and the outlet of the first booster pump (2) is connected to the delivery pipe (3).

8. The light hydrocarbon separation and cold energy power generation combined system as described in claim 1, characterized in that, It also includes a second booster pump (9) and a methane delivery pipeline (10); The inlet of the second booster pump (9) is connected to the outlet of the gas separation pipeline, and the outlet of the second booster pump (9) is connected to the methane delivery pipeline (10).

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