System and method for utilizing heat of wide-fraction hydrocarbon gas-liquid separation liquid-phase heavy components

Abstract

The invention belongs to the technical field of petrochemical engineering, and discloses a system and a method for utilizing heat of wide-fraction hydrocarbon gas-liquid separation liquid-phase heavy components. The system at least comprises a wide-fraction hydrocarbon feeding pipeline, a convection area, a gas-liquid separator, a radiation section, a combustor, a heat exchange medium supply device and a first-stage heavy component heat exchanger, and optionally comprises a wide-fraction hydrocarbon heat exchanger, an electric desalting device, an air preheater or a second-stage heavy component heat exchanger. According to the method, heat of liquid-phase heavy components obtained through gas-liquid separation is recycled to the maximum extent through a method of combining multiple heat exchange modes, the heat is integrated in a cracking furnace heat utilization system, fuel consumption of a cracking device is reduced, meanwhile, steam generated through heat exchange is further utilized, and finally the purpose of reducing energy consumption of an ethylene device is achieved. Through overall cooperation of the system, an electric desalting device, a tank field and a downstream device, the beneficial effects of reducing energy consumption and guaranteeing safety of storage and transportation facilities and the downstream device can be achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of petrochemical industry, and more specifically, relates to a system and method for utilizing heat of liquid phase heavy components in wide-fraction hydrocarbon gas-liquid separation. Background Art

[0002] Compared with traditional steam cracking, direct steam cracking of wide-fraction hydrocarbons, such as crude oil, can save the need for refining equipment such as atmospheric and vacuum distillation, and directly convert wide-fraction hydrocarbons into chemicals such as ethylene and propylene, greatly shortening the process flow, reducing production costs, and significantly reducing energy consumption and carbon emissions. Wide-fraction hydrocarbon cracking technology is of great significance in resolving the contradiction between excess refining capacity and insufficient chemical supply in my country.

[0003] Paraffin-based light low-sulfur wide-cut hydrocarbons (crude oil) have high paraffin content, low impurity content, and good cracking performance. Using them directly as steam cracking raw materials is a major research hotspot in the petrochemical industry. Since the heavy fractions of wide-cut hydrocarbons such as crude oil contain different proportions of non-volatile components such as colloids and asphaltene, when the convection section of the conventional cracking furnace is preheated, the vaporization process will move down to the high-temperature section of the furnace tube, creating conditions for the coking of these components. The non-volatile components that are not vaporized are entrained to the radiation section, which is easy to cause coking or even blockage in the radiation section under the action of high temperature, causing the device to shut down, thereby affecting the continuous production of the device and the yield of cracked olefin products. Therefore, conventional cracking furnaces do not have the flexibility to crack heavy hydrocarbon feedstocks containing a large proportion of heavy non-volatile components.

[0004] Existing technicians have conducted technical research and development to address the technical difficulties of heavy hydrocarbon cracking. Some technicians have added flash separators to the convection section of the cracking furnace to remove high-boiling point substances, so that wide-fraction hydrocarbons can be completely vaporized in the convection section, avoiding coking in the convection section gasification process and heavy components and impurities being brought into the radiation section to cause coking in the radiation section.

[0005] In order to achieve the effect of gas-liquid separation, the existing technical solutions include flash tanks and distillation towers with special flash structures to effectively control the entrainment of heavy components and impurities in the mixed materials entering the radiation section to avoid the problem of coking in the radiation section. The heat recovery of the heavy components after gas-liquid separation is beneficial to improving the energy utilization of the entire steam cracking process and reducing energy consumption, but the existing technologies fail to achieve complete heat recovery and are not flexible.

[0006] Therefore, in the current low-carbon context, it is very necessary to provide a method for effectively recovering heat from the heavy components in the liquid phase of gas-liquid separation during steam cracking of wide-fraction hydrocarbons, and effectively integrate this part of heat into the entire cracking furnace heat utilization system. Summary of the invention

[0007] The purpose of the present invention is to address the deficiencies of the prior art and propose a system and method for utilizing the heat of the liquid phase heavy component of wide-fraction hydrocarbon gas-liquid separation. The present invention recovers the heat of the liquid phase heavy component obtained by gas-liquid separation to the maximum extent through a combination of multiple heat exchange methods, and integrates it into the cracking furnace heat utilization system to reduce the energy consumption of the ethylene unit.

[0008] In order to achieve the above-mentioned object, the present invention provides, on one hand, a system for utilizing heat of a liquid phase heavy component by gas-liquid separation of wide-fraction hydrocarbons, the system comprising at least a wide-fraction hydrocarbon feed pipeline, a convection zone, a gas-liquid separator, a radiation section, a burner, a heat exchange medium supply device and a first-stage heavy component heat exchanger, and optionally a wide-fraction hydrocarbon heat exchanger, an electric desalter, an air preheater or a second-stage heavy component heat exchanger;

[0009] The liquid phase outlet of the gas-liquid separator is connected to the hot phase inlet and outlet of the first-stage heavy component heat exchanger; optionally, the hot phase outlet of the first-stage heavy component heat exchanger is connected to the hot phase inlet of the second-stage heavy component heat exchanger;

[0010] The cold phase medium of the first-stage heavy component heat exchanger is feed water for generating steam, optionally feed water for generating steam and / or the hot phase medium after heat exchange in the wide-fraction hydrocarbon heat exchanger heated by the second-stage heavy component heat exchanger;

[0011] The cold phase medium of the second-stage heavy component heat exchanger is the hot phase medium after heat exchange in the air preheater and / or the hot phase medium after heat exchange in the wide-fraction hydrocarbon heat exchanger.

[0012] In the present invention, the system further comprises a heavy component booster pump, and the liquid phase outlet of the gas-liquid separator is connected to the hot phase inlet and outlet of the first-stage heavy component heat exchanger through the heavy component booster pump.

[0013] According to the present invention, preferably, the convection zone at least includes a raw material preheating section, an upper mixed material superheating section, a dilution steam superheating section and a lower mixed material superheating section; the wide-fraction hydrocarbon feed pipeline, the cold phase inlet and outlet of the wide-fraction hydrocarbon heat exchanger, the electric desalting device, the raw material preheating section, the upper mixed material superheating section, the dilution steam superheating section, the inlet of the gas-liquid separator, the gas phase outlet of the gas-liquid separator, the lower mixed material superheating section and the radiation section are connected in sequence.

[0014] According to the present invention, preferably, the heat exchange medium supply device is connected to the quenching zone of the ethylene device.

[0015] According to the present invention, preferably, the first-stage heavy component heat exchanger is a combined structure of steam generation and superheating, preferably, the first-stage heavy component heat exchanger and the second-stage heavy component heat exchanger are heat exchangers known to those skilled in the art, and as a preferred solution, the first-stage heavy component heat exchanger and the second-stage heavy component heat exchanger are each independently a shell and tube heat exchanger and / or a sleeve and tube heat exchanger. In the present invention, as a further preferred solution, the first-stage heavy component heat exchanger and the second-stage heavy component heat exchanger are both shell and tube heat exchangers, in the first-stage heavy component heat exchanger, the liquid-phase heavy component is cooled on the tube side, and the boiler feed water is heated on the shell side to generate steam; in the second-stage heavy component heat exchanger, the liquid-phase heavy component is cooled on the shell side, and the quench water is heated on the tube side.

[0016] According to the present invention, preferably, the burner is arranged at the bottom and / or side wall of the furnace of the radiation section; the cold phase inlet of the air preheater is connected to a combustion air feed pipeline or is directly connected to the atmosphere, and the air preheater is used to preheat the combustion air entering the burner.

[0017] According to the present invention, preferably, Figure 1 As shown,

[0018] The cold phase inlet of the first-stage heavy component heat exchanger is connected to the boiler feed water equipment; the hot phase outlet of the air preheater, the cold phase inlet and outlet of the second-stage heavy component heat exchanger, the hot phase inlet and outlet of the wide-fraction hydrocarbon heat exchanger and the quench water return main pipe are connected in sequence;

[0019] The hot phase inlet of the air preheater is connected to the heat exchange medium supply device;

[0020] The cold phase outlet of the first-stage heavy component heat exchanger is connected to at least one of the dilution steam superheating section, the dilution steam main pipe of the cracking furnace, the dilution steam branch pipe of the cracking furnace and the pipe network of the ethylene device.

[0021] According to the present invention, preferably, Figure 2 As shown,

[0022] The cold phase inlet of the first-stage heavy component heat exchanger is connected to the boiler feed water equipment; the cold phase outlet of the first-stage heavy component heat exchanger is connected to at least one of the low-pressure steam pipeline network, the dilution steam superheating section, the dilution steam main pipe of the cracking furnace, the dilution steam branch pipe of the cracking furnace and the pipeline network of the ethylene device.

[0023] According to the present invention, preferably, Figure 3 As shown,

[0024] The heat exchange medium supply device, the hot phase inlet and outlet of the wide-fraction hydrocarbon heat exchanger, the cold phase inlet and outlet of the second-stage heavy component heat exchanger, the cold phase inlet and outlet of the first-stage heavy component heat exchanger, the hot phase inlet and outlet of the air preheater and the quench water return main pipe are connected in sequence.

[0025] Another aspect of the present invention provides a method for utilizing heat of a heavy component in a liquid phase of a wide-fraction hydrocarbon gas-liquid separation, the method using the system comprising:

[0026] The liquid phase heavy component obtained by the gas-liquid separator is sent to the first-stage heavy component heat exchanger. Optionally, the liquid phase heavy component after heat exchange in the first-stage heavy component heat exchanger is sent to the second-stage heavy component heat exchanger to recover and utilize the heat of the liquid phase heavy component; wherein:

[0027] The cold phase medium of the first-stage heavy component heat exchanger is feed water for generating steam, optionally feed water for generating steam and / or the hot phase medium after heat exchange in the wide-fraction hydrocarbon heat exchanger heated by the second-stage heavy component heat exchanger;

[0028] The cold phase medium of the second-stage heavy component heat exchanger is the hot phase medium after heat exchange in the air preheater and / or the hot phase medium after heat exchange in the wide-fraction hydrocarbon heat exchanger.

[0029] According to the present invention, preferably, the wide-fraction hydrocarbons subjected to the electrical desalting treatment are fed into the raw material preheating section for preheating to obtain preheated wide-fraction hydrocarbons; the preheated wide-fraction hydrocarbons are mixed and superheated with the steam of the upper mixed material superheating section and the dilution steam superheating section to obtain a mixed superheated material, which is fed into the gas-liquid separator to obtain a gas phase light component and the liquid phase heavy component; the gas phase light component is sequentially fed into the mixed material superheating section and the radiation section to be cracked to produce olefins.

[0030] According to the present invention, generally speaking, when the wide-cut hydrocarbon contains heavy components or impurities or components that cause coking, it is necessary to separate them. Usually, the wide-cut hydrocarbon is a wide-cut hydrocarbon containing a fraction with a real boiling point distillation of 540°C and above and / or a non-volatile component including a hydrocarbon mixture, impurities, etc. that are prone to produce coking components in a cracking furnace. In the present invention, it is well known to those skilled in the art that the wide-cut hydrocarbon usually contains non-volatile components. As a preferred embodiment, the wide-cut hydrocarbon is at least one of paraffin-based crude oil, intermediate-based crude oil, cycloalkyl crude oil and condensate oil, or contaminated diesel, hydrogenated tail oil, etc., or a mixture of multiple crude oils such as blended oil.

[0031] According to the present invention, preferably, the feed water for generating steam is boiler feed water and / or steam condensate; preferably, the temperature of the boiler feed water is 130-150°C.

[0032] According to the present invention, preferably, the generated steam is at least one of low-pressure steam, dilution steam and medium-pressure steam, and the temperature of the generated steam is 180-310°C. According to the temperature and pressure settings of the pipe network of different devices, a suitable generated steam temperature is selected. Preferably, the superheat of the generated dilution steam is at least 5°C, and the temperature of the dilution steam is 190-200°C.

[0033] According to the present invention, preferably, the hot phase medium of the wide-cut hydrocarbon heat exchanger is at least one of quench water, low-pressure steam, low-pressure condensate, medium-pressure steam and medium-pressure condensate from an ethylene device.

[0034] According to the present invention, preferably, the hot phase medium of the air preheater is at least one of quench water, low-pressure steam, low-pressure condensate, medium-pressure steam and medium-pressure condensate from an ethylene device.

[0035] According to the present invention, preferably,

[0036] The liquid phase heavy component is subjected to heat exchange with boiler feed water in the first-stage heavy component heat exchanger to obtain dilution steam and a first-stage cooled liquid phase heavy component; the dilution steam is used as dilution steam for the dilution steam superheating section and / or is incorporated into the pipe network of the ethylene device;

[0037] The liquid phase heavy component of the first stage cooling is heat exchanged with the quench water after heat exchange in the air preheater in the second stage heavy component heat exchanger to obtain heated quench water and the liquid phase heavy component of the second stage cooling;

[0038] The heated quench water is subjected to heat exchange with the wide-cut hydrocarbons before the electrical desalination treatment in the wide-cut hydrocarbon heat exchanger to obtain heated wide-cut hydrocarbons and cooled quench water; the heated wide-cut hydrocarbons are subjected to electrical desalination treatment; and the cooled quench water is sent to the quench water return main pipe;

[0039] Preferably, the temperature of the preheated combustion air is 50-75°C;

[0040] Preferably, the temperature of the secondary cooled liquid phase heavy component is 70-110°C, preferably 75-95°C.

[0041] In the present invention, the method of "using the dilution steam as the dilution steam of the dilution steam superheating section" includes: the dilution steam can enter the convection zone at any position, for example, it can be returned to the dilution steam main pipe, enter the dilution steam superheating section of the convection zone of the cracking furnace together and after being superheated, it is injected into the raw material pipeline before or after heating in the convection zone to form a mixed material.

[0042] According to the present invention, preferably,

[0043] The liquid phase heavy component is heat exchanged with boiler feed water in the first-stage heavy component heat exchanger to obtain low-pressure steam and cooled liquid phase heavy components; the low-pressure steam is introduced into the pipe network of the ethylene device;

[0044] Preferably, the temperature of the low pressure steam is 180-250°C.

[0045] Preferably, the temperature of the cooled liquid phase heavy component is 160-250°C.

[0046] According to the present invention, preferably,

[0047] exchanging heat between the quench water from the quench zone of the ethylene unit and the wide-cut hydrocarbons before the electrical desalination treatment in the wide-cut hydrocarbon heat exchanger to obtain heated wide-cut hydrocarbons and cooled quench water; and subjecting the heated wide-cut hydrocarbons to the electrical desalination treatment;

[0048] The cooled quench water and the first-stage cooled liquid-phase heavy component after heat exchange in the first-stage heavy component heat exchanger are heat exchanged in the second-stage heavy component heat exchanger to obtain heated quench water and the second-stage cooled liquid-phase heavy component;

[0049] Exchanging heat between the heated quench water and the liquid phase heavy component in the first-stage heavy component heat exchanger to obtain secondary heated quench water and the first-stage cooled liquid phase heavy component after heat exchange in the first-stage heavy component heat exchanger;

[0050] The secondary heated quench water and the combustion air are heat exchanged in the air preheater to obtain cooled quench water and preheated combustion air; the cooled quench water is sent to the quench water return main pipe; the preheated combustion air is sent to the burner;

[0051] Preferably, the temperature of the liquid phase heavy component of the secondary cooling is 70-110°C, preferably 75-95°C;

[0052] Preferably, the temperature of the preheated combustion air is 50-75°C.

[0053] In the present invention, the cooled liquid-phase heavy component obtained by heat exchange in the first-stage heavy component heat exchanger and optionally the second-stage heavy component heat exchanger is finally sent to a storage tank or a downstream device.

[0054] The beneficial effects of the technical solution of the present invention are as follows:

[0055] 1. The present invention recovers the heat of the liquid phase heavy component obtained by gas-liquid separation to the maximum extent through a combination of multiple heat exchange modes, and integrates it into the heat utilization system of the cracking furnace, thereby reducing the fuel consumption of the cracking device and ultimately achieving the purpose of reducing the energy consumption of the ethylene device.

[0056] 2. The present invention further utilizes the steam generated by heat exchange: the generated dilution steam enters the convection section of the cracking furnace for overheating; the generated low-pressure steam and medium-pressure steam can be incorporated into the corresponding pipeline network of the ethylene device to achieve the purpose of reducing the energy consumption of the ethylene device.

[0057] 3. Through this system and the overall coordination with the electric desalination device, tank area and downstream devices, it is possible to reduce energy consumption and ensure the safety of storage and transportation facilities and downstream devices.

[0058] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0060] Figure 1 A schematic diagram of a system for utilizing heat of liquid-phase heavy components in gas-liquid separation of wide-fraction hydrocarbons provided in Example 1 of the present invention is shown.

[0061] Figure 2 The schematic diagram of a system for utilizing heat of liquid phase heavy components in gas-liquid separation of wide-fraction hydrocarbons provided by the present invention is shown.

[0062] Figure 3 A schematic diagram of a system for utilizing heat of liquid-phase heavy components in gas-liquid separation of wide-fraction hydrocarbons provided in Example 2 of the present invention is shown.

[0063] The following are the descriptions of the reference numerals:

[0064] 1: gas-liquid separator, 2: heavy component booster pump, 3: first stage heavy component heat exchanger, 4: second stage heavy component heat exchanger, 5: burner, 6: air preheater, 7: convection zone, 8: radiation section, 9: wide-fraction hydrocarbon heat exchanger, 10: electric desalting device, 11: wide-fraction hydrocarbon feed pipeline, 12: heat exchange medium supply device, 13: raw material preheating section, 14-1: upper mixed material superheating section, 14-2: dilution steam superheating section, 15: lower mixed material superheating section, 16: gas-liquid separator inlet 17: gas phase outlet of gas-liquid separator, 18: liquid phase outlet of gas-liquid separator, 19: boiler feed water, 20: quench water return main pipe, 21: boiler feed water, 22: dilution steam, 23: primary dilution steam pipeline, 24: secondary dilution steam pipeline, 25: quench water from the quenching zone of ethylene unit, 26: quench water after heat exchange in the air preheater, 27: low-pressure steam, 28: quench water after heat exchange in the wide-cut hydrocarbon heat exchanger, 29: liquid phase heavy components of secondary cooling. DETAILED DESCRIPTION

[0065] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0066] Example 1

[0067] This embodiment provides a system for utilizing heat of a liquid phase heavy component in a wide-fraction hydrocarbon gas-liquid separation, such as Figure 1 As shown, the system includes a wide-fraction hydrocarbon feed pipeline 11, a wide-fraction hydrocarbon heat exchanger 9, an electric desalting device 10, a convection zone 7, a gas-liquid separator 1, a heavy component booster pump 2, a radiation section 8, a burner 5, an air preheater 6, a heat exchange medium supply device 12, a first-stage heavy component heat exchanger 3, and a second-stage heavy component heat exchanger 4;

[0068] The convection zone 7 includes a raw material preheating section 13, an upper mixed material superheating section 14-1, a dilution steam superheating section 14-2 and a lower mixed material superheating section 15; the wide-fraction hydrocarbon feed pipeline 11, the cold phase inlet and outlet of the wide-fraction hydrocarbon heat exchanger 9, the electric desalting device 10, the raw material preheating section 13, the upper mixed material superheating section 14-1, the dilution steam superheating section 14-2, the inlet 16 of the gas-liquid separator, the gas phase outlet 17 of the gas-liquid separator, the lower mixed material superheating section 15 and the radiation section 8 are connected in sequence;

[0069] The liquid phase outlet 18 of the gas-liquid separator, the heavy component booster pump 2, the hot phase inlet and outlet of the first-stage heavy component heat exchanger 3, and the hot phase inlet and outlet of the second-stage heavy component heat exchanger 4 are connected in sequence;

[0070] The cold phase inlet of the first-stage heavy component heat exchanger 3 is connected to the boiler feed water equipment (not shown); the hot phase outlet of the air preheater 6, the cold phase inlet and outlet of the second-stage heavy component heat exchanger 4, the hot phase inlet and outlet of the wide-fraction hydrocarbon heat exchanger 9 and the quench water return main pipe 20 are connected in sequence; the hot phase inlet of the air preheater 6 is connected to the heat exchange medium supply device 12;

[0071] The cold phase outlet of the first-stage heavy component heat exchanger 3 is connected to the dilution steam superheating section 14 - 2 .

[0072] The heat exchange medium supply device 12 is connected to the quenching zone (not shown) of the ethylene device;

[0073] The first-stage heavy component heat exchanger 3 and the second-stage heavy component heat exchanger 4 are both shell and tube heat exchangers;

[0074] The burner 5 is arranged at the bottom and / or side wall of the furnace of the radiation section 8; the cold phase inlet of the air preheater 6 is connected to a combustion air feed pipeline, and the air preheater 6 is used to preheat the combustion air entering the burner.

[0075] This embodiment also provides a method for utilizing heat of a liquid phase heavy component in a gas-liquid separation of a wide-cut hydrocarbon, wherein the API value of the wide-cut hydrocarbon is 43.9 and the flow rate is 250 t / h. The method uses the above-mentioned system and comprises the following steps:

[0076] S1: The wide-cut hydrocarbons treated by electric desalting are sent to the raw material preheating section 13 for preheating to obtain preheated wide-cut hydrocarbons; the preheated wide-cut hydrocarbons are mixed with the steam of the upper mixed material superheating section 14-1 and the dilution steam superheating section 14-2 and superheated to obtain a mixed superheated material, which is sent to the gas-liquid separator 1 to obtain a gas phase light component (temperature of 310°C, final distillation point of 456°C) and 50t / h liquid phase heavy component (temperature of 390°C, initial distillation point of 404°C, final distillation point of 655°C (98% distillation, ASTM D86 simulation data));

[0077] S2: The gas phase light component is sequentially sent to the lower mixed material superheating section 15 and the radiation section 8 to be cracked to produce olefins; the liquid phase heavy component is pressurized and drawn out by the heavy component booster pump 2, and sequentially sent to the first stage heavy component heat exchanger 3 and the second stage heavy component heat exchanger 4 to recover and utilize the heat of the liquid phase heavy component, specifically:

[0078] The liquid phase heavy component (temperature is 390°C, 50t / h) is heat exchanged with boiler feed water 19 (143.7°C, 6.2t / h) in the first-stage heavy component heat exchanger 3 to obtain dilution steam 22 (178°C, 0.76MPaG) and a first-stage cooled liquid phase heavy component (180°C), and 7.5MW of heat is recovered; the dilution steam is sent to the primary dilution steam pipeline 23 and injected into the raw material at the outlet of the raw material preheating section 13;

[0079] The quenching water 25 (82°C, 200t / h) from the quenching zone of the ethylene unit is heat exchanged with air in the bottom and side wall air preheaters 6 respectively to obtain preheated combustion air (62°C) and quenching water 26 (65°C) after heat exchange in the air preheater, and 4.55MW of heat is recovered; the preheated combustion air enters the cracking furnace through the burner and burns together with the fuel gas, and the fuel consumption of the cracking furnace can be reduced by 570kg / h;

[0080] The liquid phase heavy component (180°C) of the first-stage cooling is exchanged with the quench water 26 (65°C) after heat exchange in the air preheater in the second-stage heavy component heat exchanger 4 to obtain heated quench water (76°C) and the liquid phase heavy component (90°C) of the second-stage cooling, and 2.6MW of heat is recovered; the liquid phase heavy component (90°C) of the second-stage cooling is sent to the storage tank;

[0081] The heated quench water (76°C) is heat exchanged with the wide-cut hydrocarbons before electrical desalination treatment in the wide-cut hydrocarbon heat exchanger 9 to obtain heated wide-cut hydrocarbons (130°C) and cooled quench water (60°C), and 4.47MW of heat is recovered; the heated wide-cut hydrocarbons (130°C) are subjected to electrical desalination treatment (including desalination, dehydration and pretreatment for removal of non-metallic impurities); and the cooled quench water (60°C) is sent to the quench water return main pipe.

[0082] Example 2

[0083] This embodiment provides a system for utilizing heat of a liquid phase heavy component in a wide-fraction hydrocarbon gas-liquid separation, such as Figure 2 As shown, the system includes a wide-fraction hydrocarbon feed pipeline 11, an electric desalting device 10, a convection zone 7, a gas-liquid separator 1, a heavy component booster pump 2, a radiation section 8, and a first-stage heavy component heat exchanger 3;

[0084] The convection zone 7 includes a raw material preheating section 13, an upper mixed material superheating section 14-1, a dilution steam superheating section 14-2 and a lower mixed material superheating section 15; the wide-fraction hydrocarbon feed pipeline 11, the electric desalting device 10, the raw material preheating section 13, the upper mixed material superheating section 14-1, the dilution steam superheating section 14-2, the inlet 16 of the gas-liquid separator, the gas phase outlet 17 of the gas-liquid separator, the lower mixed material superheating section 15 and the radiation section 8 are connected in sequence;

[0085] The liquid phase outlet 18 of the gas-liquid separator, the heavy component booster pump 2, and the hot phase inlet and outlet of the first-stage heavy component heat exchanger 3 are connected in sequence;

[0086] The first-stage heavy component heat exchanger 3 is a shell and tube heat exchanger.

[0087] This embodiment also provides a method for utilizing heat of a heavy component in a liquid phase of a wide-cut hydrocarbon gas-liquid separation, wherein the API value of the wide-cut hydrocarbon is 44.5 and the flow rate is 73 t / h. The method uses the above-mentioned system and comprises the following steps:

[0088] S1: The wide-cut hydrocarbons (130° C.) treated by electric desalting are sent to the raw material preheating section 13 for preheating to obtain preheated wide-cut hydrocarbons; the preheated wide-cut hydrocarbons are mixed and superheated with the steam of the upper mixed material superheating section 14-1 and the dilution steam superheating section 14-2 to obtain a mixed superheated material, which is sent to the gas-liquid separator 1 to obtain a gas phase light component and 10 t / h liquid phase heavy component (temperature is 320° C., final distillation point is 750° C. (98% distillation, ASTM D86 simulation data));

[0089] S2: The gas phase light component is sequentially sent to the lower mixed material superheating section 15 and the radiation section 8 to be cracked to produce olefins; the liquid phase heavy component is pressurized and drawn out by the heavy component booster pump 2, and sent to the first stage heavy component heat exchanger 3 to recover and utilize the heat of the liquid phase heavy component, specifically:

[0090] The liquid phase heavy component (temperature is 320°C, 10t / h) is heat exchanged with boiler feed water 19 in the first-stage heavy component heat exchanger 3 to obtain low-pressure steam 27 (152°C, 0.4MpaG) and cooled liquid phase heavy components (160°C), and 1.2MW of heat is recovered; the low-pressure steam 27 is sent to the primary dilution steam pipeline 23, and the cooled liquid phase heavy components are sent to the downstream device for further recycling.

[0091] Example 3

[0092] This embodiment provides a system for utilizing heat of a liquid phase heavy component in a wide-fraction hydrocarbon gas-liquid separation, such as Figure 3 As shown, the system includes a wide-fraction hydrocarbon feed pipeline 11, a wide-fraction hydrocarbon heat exchanger 9, an electric desalting device 10, a convection zone 7, a gas-liquid separator 1, a heavy component booster pump 2, a radiation section 8, a burner 5, an air preheater 6, a heat exchange medium supply device 12, a first-stage heavy component heat exchanger 3, and a second-stage heavy component heat exchanger 4;

[0093] The convection zone 7 includes a raw material preheating section 13, an upper mixed material superheating section 14-1, a dilution steam superheating section 14-2 and a lower mixed material superheating section 15; the wide-fraction hydrocarbon feed pipeline 11, the cold phase inlet and outlet of the wide-fraction hydrocarbon heat exchanger 9, the electric desalting device 10, the raw material preheating section 13, the upper mixed material superheating section 14-1, the dilution steam superheating section 14-2, the inlet 16 of the gas-liquid separator, the gas phase outlet 17 of the gas-liquid separator, the lower mixed material superheating section 15 and the radiation section 8 are connected in sequence;

[0094] The liquid phase outlet 18 of the gas-liquid separator, the heavy component booster pump 2, the hot phase inlet and outlet of the first-stage heavy component heat exchanger 3, and the hot phase inlet and outlet of the second-stage heavy component heat exchanger 4 are connected in sequence;

[0095] The heat exchange medium supply device 12, the hot phase inlet and outlet of the wide-fraction hydrocarbon heat exchanger 9, the cold phase inlet and outlet of the second-stage heavy component heat exchanger 4, the cold phase inlet and outlet of the first-stage heavy component heat exchanger 3, the hot phase inlet and outlet of the air preheater 6 and the quench water return main pipe 20 are connected in sequence.

[0096] The heat exchange medium supply device 12 is connected to the quenching zone (not shown) of the ethylene device;

[0097] The first-stage heavy component heat exchanger 3 and the second-stage heavy component heat exchanger 4 are both shell and tube heat exchangers;

[0098] The burner 5 is arranged at the bottom and / or side wall of the furnace of the radiation section 8; the cold phase inlet of the air preheater 6 is connected to a combustion air feed pipeline, and the air preheater 6 is used to preheat the combustion air entering the burner.

[0099] This embodiment also provides a method for utilizing heat of a liquid phase heavy component in a gas-liquid separation of wide-cut hydrocarbons, wherein the API value of the wide-cut hydrocarbons is 43.9 and the flow rate is 250 t / h. The method uses the above-mentioned system and comprises the following steps:

[0100] S1: The wide-cut hydrocarbons (130°C) treated by electrical desalting are sent to the raw material preheating section 13 for preheating to obtain preheated wide-cut hydrocarbons; the preheated wide-cut hydrocarbons are mixed and superheated with the steam of the upper mixed material superheating section 14-1 and the dilution steam superheating section 14-2 to obtain a mixed superheated material, which is sent to the gas-liquid separator 1 to obtain a gas phase light component (temperature of 310°C, final distillation point of 456°C) and 50t / h liquid phase heavy component (temperature of 390°C, initial distillation point of 404°C, final distillation point of 655°C (ASTM D86 simulation data));

[0101] S2: The gas phase light component is sequentially sent to the lower mixed material superheating section 15 and the radiation section 8 to be cracked to produce olefins; the liquid phase heavy component is pressurized and drawn out by the heavy component booster pump 2, and sequentially sent to the first stage heavy component heat exchanger 3 and the second stage heavy component heat exchanger 4 to recover and utilize the heat of the liquid phase heavy component, specifically:

[0102] The quench water (82°C, 291 t / h) from the quench zone of the ethylene unit is heat exchanged with the wide-cut hydrocarbons before the electrical desalination treatment in the wide-cut hydrocarbon heat exchanger to obtain heated wide-cut hydrocarbons (130°C) and cooled quench water (70°C), and 4.5 MW of heat is recovered; the heated wide-cut hydrocarbons are desalted, dehydrated, and pre-treated to remove impurities such as non-metals, to obtain the wide-cut hydrocarbons after the electrical desalination treatment of step S1;

[0103] The cooled quench water and the first-stage cooled liquid phase heavy component after heat exchange in the first-stage heavy component heat exchanger are heat exchanged in the second-stage heavy component heat exchanger to obtain heated quench water and the second-stage cooled liquid phase heavy component (90° C.);

[0104] The heated quench water and the liquid phase heavy component are heat exchanged in the first-stage heavy component heat exchanger to obtain secondary heated quench water (94° C.) and the first-stage cooled liquid phase heavy component after heat exchange in the first-stage heavy component heat exchanger;

[0105] Recovered heat 7.7MW;

[0106] The secondary heated quench water and combustion air are heat exchanged in the air preheater to obtain cooled quench water (76°C) and preheated combustion air (72°C), and 6MW of heat is recovered; the cooled quench water is sent to the quench water return main pipe; the preheated combustion air is sent to the burner, and the fuel consumption of the cracking furnace can be reduced by 720kg / h.

[0107] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A system for utilizing heat of liquid phase heavy components in gas-liquid separation of wide-fraction hydrocarbons, characterized in that: The system comprises at least a wide-cut hydrocarbon feed line, a convection zone, a gas-liquid separator, a radiant section, a burner, a heat exchange medium supply device and a first-stage heavy component heat exchanger, and optionally a wide-cut hydrocarbon heat exchanger, an electric desalter, an air preheater or a second-stage heavy component heat exchanger; The liquid phase outlet of the gas-liquid separator is connected to the hot phase inlet and outlet of the first-stage heavy component heat exchanger; optionally, the hot phase outlet of the first-stage heavy component heat exchanger is connected to the hot phase inlet of the second-stage heavy component heat exchanger; The cold phase medium of the first-stage heavy component heat exchanger is feed water for generating steam, optionally feed water for generating steam and / or the hot phase medium after heat exchange in the wide-fraction hydrocarbon heat exchanger heated by the second-stage heavy component heat exchanger; The cold phase medium of the second-stage heavy component heat exchanger is the hot phase medium after heat exchange in the air preheater and / or the hot phase medium after heat exchange in the wide-fraction hydrocarbon heat exchanger.

2. The system for utilizing heat of liquid phase heavy components from gas-liquid separation of wide-cut hydrocarbons according to claim 1, wherein: The convection zone at least includes a raw material preheating section, an upper mixed material superheating section, a dilution steam superheating section and a lower mixed material superheating section; the wide-fraction hydrocarbon feed pipeline, the cold phase inlet and outlet of the wide-fraction hydrocarbon heat exchanger, the electric desalting device, the raw material preheating section, the upper mixed material superheating section, the dilution steam superheating section, the inlet of the gas-liquid separator, the gas phase outlet of the gas-liquid separator, the lower mixed material superheating section and the radiation section are connected in sequence; The heat exchange medium supply device is connected to the quenching zone of the ethylene device; The first-stage heavy component heat exchanger is a steam generation and superheating combined structure. Preferably, the first-stage heavy component heat exchanger and the second-stage heavy component heat exchanger are each independently a shell and tube heat exchanger and / or a sleeve and tube heat exchanger; The burner is arranged at the bottom and / or side wall of the furnace of the radiation section; the cold phase inlet of the air preheater is connected to a combustion air feed pipeline or is directly connected to the atmosphere, and the air preheater is used to preheat the combustion air entering the burner.

3. The system for utilizing heat of liquid phase heavy components from gas-liquid separation of wide-cut hydrocarbons according to claim 2, wherein: The cold phase inlet of the first-stage heavy component heat exchanger is connected to the boiler feed water equipment; the hot phase outlet of the air preheater, the cold phase inlet and outlet of the second-stage heavy component heat exchanger, the hot phase inlet and outlet of the wide-fraction hydrocarbon heat exchanger and the quench water return main pipe are connected in sequence; The hot phase inlet of the air preheater is connected to the heat exchange medium supply device; The cold phase outlet of the first-stage heavy component heat exchanger is connected to at least one of the dilution steam superheating section, the dilution steam main pipe of the cracking furnace, the dilution steam branch pipe of the cracking furnace and the pipe network of the ethylene device.

4. The system for utilizing heat of liquid phase heavy components from gas-liquid separation of wide-cut hydrocarbons according to claim 2, wherein: The cold phase inlet of the first-stage heavy component heat exchanger is connected to the boiler feed water equipment; The cold phase outlet of the first-stage heavy component heat exchanger is connected to at least one of the low-pressure steam network, the dilution steam superheating section, the dilution steam main pipe of the cracking furnace, the dilution steam branch pipe of the cracking furnace and the network of the ethylene device.

5. The system for utilizing heat of liquid phase heavy components from gas-liquid separation of wide-cut hydrocarbons according to claim 2, wherein: The heat exchange medium supply device, the hot phase inlet and outlet of the wide-fraction hydrocarbon heat exchanger, the cold phase inlet and outlet of the second-stage heavy component heat exchanger, the cold phase inlet and outlet of the first-stage heavy component heat exchanger, the hot phase inlet and outlet of the air preheater and the quench water return main pipe are connected in sequence.

6. A method for utilizing heat of heavy components in liquid phase of wide-fraction hydrocarbon gas-liquid separation, characterized in that: The method adopts the system according to any one of claims 1 to 5, comprising: The liquid phase heavy component obtained by the gas-liquid separator is sent to the first-stage heavy component heat exchanger. Optionally, the liquid phase heavy component after heat exchange in the first-stage heavy component heat exchanger is sent to the second-stage heavy component heat exchanger to recover and utilize the heat of the liquid phase heavy component; wherein: The cold phase medium of the first-stage heavy component heat exchanger is feed water for generating steam, optionally feed water for generating steam and / or the hot phase medium after heat exchange in the wide-fraction hydrocarbon heat exchanger heated by the second-stage heavy component heat exchanger; The cold phase medium of the second-stage heavy component heat exchanger is the hot phase medium after heat exchange in the air preheater and / or the hot phase medium after heat exchange in the wide-fraction hydrocarbon heat exchanger.

7. The method for utilizing heat of liquid phase heavy components in gas-liquid separation of wide-cut hydrocarbons according to claim 6, wherein: The wide-fraction hydrocarbons treated by electrical desalination are sent to the raw material preheating section for preheating to obtain preheated wide-fraction hydrocarbons; the preheated wide-fraction hydrocarbons are mixed with the steam of the upper mixed material superheating section and the dilution steam superheating section and superheated to obtain a mixed superheated material, which is sent to the gas-liquid separator to obtain a gas phase light component and the liquid phase heavy component; the gas phase light component is sent to the lower mixed material superheating section and the radiation section in sequence to be cracked to produce olefins; The feed water for generating steam is boiler feed water and / or steam condensate; preferably, the temperature of the boiler feed water is 130-150°C; The generated steam is at least one of low-pressure steam, dilution steam and medium-pressure steam, and the temperature of the generated steam is 180-310°C; preferably, the superheat of the generated dilution steam is at least 5°C, and the temperature of the dilution steam is 190-200°C; The hot phase medium of the wide-cut hydrocarbon heat exchanger is at least one of quench water, low-pressure steam, low-pressure condensate, medium-pressure steam and medium-pressure condensate from the ethylene device; The hot phase medium of the air preheater is at least one of quench water, low-pressure steam, low-pressure condensate, medium-pressure steam and medium-pressure condensate from the ethylene device.

8. The method for utilizing heat of liquid phase heavy components in gas-liquid separation of wide-cut hydrocarbons according to claim 7, wherein: The liquid phase heavy component is subjected to heat exchange with boiler feed water in the first-stage heavy component heat exchanger to obtain dilution steam and a first-stage cooled liquid phase heavy component; the dilution steam is used as dilution steam for the dilution steam superheating section and / or is incorporated into the pipe network of the ethylene device; The liquid phase heavy component of the first stage cooling is heat exchanged with the quench water after heat exchange in the air preheater in the second stage heavy component heat exchanger to obtain heated quench water and the liquid phase heavy component of the second stage cooling; The heated quench water is subjected to heat exchange with the wide-cut hydrocarbons before the electrical desalination treatment in the wide-cut hydrocarbon heat exchanger to obtain heated wide-cut hydrocarbons and cooled quench water; the heated wide-cut hydrocarbons are subjected to electrical desalination treatment; and the cooled quench water is sent to the quench water return main pipe; Preferably, the temperature of the preheated combustion air is 50-75°C.

9. The method for utilizing heat of liquid phase heavy components in gas-liquid separation of wide-cut hydrocarbons according to claim 7, wherein: The liquid phase heavy component is heat exchanged with boiler feed water in the first-stage heavy component heat exchanger to obtain low-pressure steam and cooled liquid phase heavy components; the low-pressure steam is introduced into the pipe network of the ethylene device.

10. The method for utilizing heat of liquid phase heavy components in gas-liquid separation of wide-cut hydrocarbons according to claim 7, wherein: exchanging heat between the quench water from the quench zone of the ethylene unit and the wide-cut hydrocarbons before the electrical desalination treatment in the wide-cut hydrocarbon heat exchanger to obtain heated wide-cut hydrocarbons and cooled quench water; and subjecting the heated wide-cut hydrocarbons to the electrical desalination treatment; The cooled quench water and the first-stage cooled liquid-phase heavy component after heat exchange in the first-stage heavy component heat exchanger are heat exchanged in the second-stage heavy component heat exchanger to obtain heated quench water and the second-stage cooled liquid-phase heavy component; Exchanging heat between the heated quench water and the liquid phase heavy component in the first-stage heavy component heat exchanger to obtain secondary heated quench water and the first-stage cooled liquid phase heavy component after heat exchange in the first-stage heavy component heat exchanger; The secondary heated quench water and the combustion air are heat exchanged in the air preheater to obtain cooled quench water and preheated combustion air; the cooled quench water is sent to the quench water return main pipe; the preheated combustion air is sent to the burner; Preferably, the temperature of the preheated combustion air is 50-75°C.

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