Ethylene gasification heat utilization system

Abstract

The invention provides an ethylene gasification heat utilization system which comprises an ethylene gasification subsystem and an oil gas condensation recovery subsystem in heat transfer connection with the ethylene gasification subsystem, the ethylene gasification subsystem absorbs heat of oil gas of the oil gas condensation recovery subsystem when gasifying ethylene, so that the oil gas is cooled to form a liquid-phase organic working medium and waste gas, the oil gas condensation recovery subsystem comprises an oil gas source, a heat exchange assembly, a gas-liquid separator and a condensate collector, the heat exchange assembly is connected with the ethylene gasification subsystem, oil gas of the oil gas source is introduced into the heat exchange assembly, and the ethylene gasification subsystem absorbs heat of the oil gas through the heat exchange assembly, so that the oil gas is cooled; the cooled oil gas is subjected to gas-liquid separation through a gas-liquid separator, the separated condensed liquid-phase organic working medium is introduced into a condensate collector, and the separated waste gas is discharged into the atmosphere; regasification cold energy of external liquid ethylene is adopted for condensation recovery of oil gas, exhaust pollution is avoided, active refrigeration does not need to consume electric energy, and economic losses are reduced.

Description

Technical Field

[0001] The present invention relates to the technical fields of the utilization of the regasification cold energy of liquid ethylene and oil and gas recovery, and particularly relates to an ethylene gasification heat utilization system. Background Art

[0002] In the chemical industries such as petroleum and pharmaceuticals, there are a large number of oil and gas emissions containing volatile organic compounds. The volatile organic compounds in the oil and gas pollute the environment and cannot be directly discharged. Therefore, there is a need and necessity to treat the oil and gas. The existing treatment methods include direct combustion and recovery treatment. Among them, the direct combustion schemes include RTO, catalytic combustion, etc., which have the disadvantages of high combustion energy consumption, dependence on catalysts, a large amount of carbon dioxide in the combustion exhaust gas aggravating the greenhouse effect, and the waste of the relatively high economic value of the organic working medium. The oil and gas recovery treatment technology has emerged as the times require. The oil and gas recovery treatment methods include adsorption, absorption, and condensation recovery, etc. The adsorption and absorption methods require additional equipment such as adsorbers and absorption towers, while the traditional condensation recovery requires refrigeration by a refrigerator, consuming a large amount of electric energy.

[0003] Ethylene is a cornerstone product in the petrochemical industry. Many downstream chemical products are produced with ethylene as the raw material, including polyethylene (PE), ethylene glycol, ethylene oxide, styrene, polyvinyl chloride, etc. Ethylene is stored and transported in a low-temperature liquid state under near-atmospheric pressure and at -104 to -100 °C, and before being sent to downstream ethylene users, it needs to be pressurized and heated to a high-pressure normal-temperature gas state. The gasification of liquid ethylene requires heat absorption, and the conventional gasification process of liquid ethylene is usually achieved by direct heating with low-temperature steam. In this process, the regasification cold energy of liquid ethylene is not reasonably utilized, and this part of the cold energy is wasted in large quantities. At the same time, a large amount of steam heat is consumed, resulting in a double loss of cold energy and heat energy. Summary of the Invention

[0004] The purpose of the present invention is to solve the technical problems in the prior art that the gasification process of liquid ethylene requires the consumption of steam heat and the regasification cold energy of ethylene is wasted in large quantities, while the traditional condensation recovery requires refrigeration by a refrigerator, consuming a large amount of electric energy.

[0005] To solve the above technical problems, the present invention provides an ethylene gasification heat utilization system, which includes: an ethylene gasification subsystem and an oil-gas condensation recovery subsystem heat-transfer connected to the ethylene gasification subsystem. When the ethylene gasification subsystem gasifies ethylene, it absorbs the heat of the oil-gas in the oil-gas condensation recovery subsystem, cooling the oil-gas to form a liquid-phase organic working medium and waste gas. Among them, the oil-gas condensation recovery subsystem includes an oil-gas source, a heat exchange component, a gas-liquid separator, and a condensate collector. The heat exchange component is connected to the ethylene gasification subsystem. The oil-gas from the oil-gas source is introduced into the heat exchange component. The ethylene gasification subsystem absorbs the heat of the oil-gas through the heat exchange component, cooling the oil-gas. The cooled oil-gas is subjected to gas-liquid separation through the gas-liquid separator. The separated condensed liquid-phase organic working medium is introduced into the condensate collector, and the separated waste gas is discharged into the atmosphere.

[0006] Furthermore, the ethylene gasification subsystem includes an ethylene source and an intermediate heat exchanger. The intermediate heat exchanger has a first heat exchange side and a second heat exchange side. The ethylene source is connected to the input end of the first heat exchange side. The heat exchange component is connected to the input end and the output end of the second heat exchange side through pipelines. The heat exchange component and the second heat exchange side form a first circulation loop, and an intermediate heat exchange medium circulates in the first circulation loop. When liquid ethylene is introduced into the intermediate heat exchanger, the intermediate heat exchange medium exchanges heat with the liquid ethylene in the intermediate heat exchanger, gasifying the liquid ethylene and releasing high-grade cold energy. The intermediate heat exchange medium absorbs the cold energy and cools down to a low temperature state. The intermediate heat exchange medium in the low temperature state is introduced into the heat exchange component to exchange heat with the oil-gas, cooling the oil-gas. The liquid ethylene after heat exchange is transformed into gaseous ethylene, and the gaseous ethylene is output outward through the output end of the first heat exchange side.

[0007] Furthermore, the heat exchange component includes a cryogenic heat exchanger and an intermediate heat exchanger connected in series. The intermediate heat exchange medium cooled to the low temperature state passes through the cryogenic heat exchanger and the intermediate heat exchanger in sequence. The oil-gas from the oil-gas source is sequentially transported to the intermediate heat exchanger and the cryogenic heat exchanger through pressurization.

[0008] Furthermore, it also includes a pre-cooling heat exchanger connected in series with the cryogenic heat exchanger and the intermediate heat exchanger. The intermediate heat exchange medium cooled to the low temperature state passes through the cryogenic heat exchanger, the intermediate heat exchanger, and the pre-cooling heat exchanger in sequence. The oil-gas from the oil-gas source is sequentially transported to the pre-cooling heat exchanger, the intermediate heat exchanger, and the cryogenic heat exchanger through pressurization.

[0009] Furthermore, the gas-liquid separator includes a cryogenic separator and an intermediate separator. The oil-gas cooled by the intermediate separator enters the intermediate separator for gas-liquid separation. The separated liquid-phase organic working medium is introduced into the condensate collector. The separated gaseous oil-gas is introduced into the cryogenic heat exchanger and cooled to the cryogenic state by the cryogenic heat exchanger. The oil-gas in the cryogenic state enters the cryogenic separator for gas-liquid separation. The separated liquid-phase organic working medium is introduced into the condensate collector, and the separated waste gas is discharged into the atmosphere.

[0010] Further, the gas-liquid separator includes a cryogenic separator, an intermediate cooler separator, and a precooling separator. The oil and gas cooled by the precooling separator enters the precooling separator for gas-liquid separation. The separated liquid-phase organic working medium is introduced into the condensate collector, and the separated gas-phase oil and gas is introduced into the intermediate cooler separator. The oil and gas cooled by the intermediate cooler separator enters the intermediate cooler separator for gas-liquid separation. The separated liquid-phase organic working medium is introduced into the condensate collector, and the separated gas-phase oil and gas is introduced into the cryogenic heat exchanger and cooled to the cryogenic state by the cryogenic heat exchanger. The oil and gas in the cryogenic state enters the cryogenic separator for gas-liquid separation. The separated liquid-phase organic working medium is introduced into the condensate collector, and the exhausted gas separated is discharged into the atmosphere.

[0011] Further, the exhausted gas separated by the cryogenic separator is introduced into the precooling heat exchanger. The exhausted gas exchanges heat with the oil and gas in the precooling heat exchanger, and the exhausted gas releases the remaining cold energy and is discharged into the atmosphere through the precooling heat exchanger.

[0012] Further, it also includes a low-grade cold energy heat exchanger and a cold user. The low-grade cold energy heat exchanger is connected to the first heat exchange side pipeline of the intermediate heat exchanger. The intermediate cold gaseous ethylene is introduced into the low-grade cold energy heat exchanger. The intermediate cold gaseous ethylene exchanges heat with the cold user through the low-grade cold energy heat exchanger to release low-grade cold energy, and the intermediate cold gaseous ethylene after heat exchange is heated to normal temperature gaseous ethylene.

[0013] Further, the low-grade cold energy heat exchanger has a third heat exchange side and a fourth heat exchange side. The output end of the first heat exchange side of the intermediate heat exchanger is connected to the input end of the third heat exchange side through a pipeline, and the cold user is connected to the output end and the input end of the fourth heat exchange side through pipelines. The cold user and the fourth heat exchange side form a second circulation loop, and a cold delivery working medium circulates in the second circulation loop.

[0014] Further, it also includes an ethylene pump. The input end of the ethylene pump is connected to the ethylene source through a pipeline, and the output end of the ethylene pump is connected to the input end of the first heat exchange side through a pipeline. The ethylene pump drives the liquid ethylene to flow towards the intermediate heat exchanger, so that the pressure of the liquid ethylene is increased to the target gasification pressure.

[0015] As can be seen from the above technical solutions, the beneficial effects of the present invention are as follows: The re-gasification cold energy of external liquid ethylene is used for the condensation recovery of oil and gas, which not only has no exhaust gas pollution, but also does not require active refrigeration by consuming electric energy. It reasonably utilizes the gasification cold energy of ethylene, reduces cold energy waste, and recovers the economic loss caused by the emission of organic working medium. Description of the Drawings

[0017] Figure 1 is a schematic diagram of the ethylene gasification heat utilization system provided by this application. Detailed Embodiments

[0018] Typical embodiments embodying the features and advantages of the present invention will be described in detail in the following description. It should be understood that the present invention can have various variations in different embodiments, all of which do not depart from the scope of the present invention, and the descriptions and illustrations therein are for illustrative purposes in nature and not intended to limit the present invention.

[0019] In the description of the present application, it should be understood that the orientation or positional relationship indicated by terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present application. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present application, "a plurality" means two or more, unless otherwise specifically defined.

[0020] To further illustrate the principle and structure of the present invention, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0021] Please refer to Figure 1 , a system for utilizing the heat of ethylene gasification provided in this embodiment, includes: an ethylene gasification subsystem 100, an oil and gas fractional condensation and recovery subsystem (oil and gas condensation and recovery subsystem) 200.

[0022] The ethylene gasification subsystem 100 includes a cryogenic liquid ethylene source 1, an ethylene pump 2, an intermediate heat exchanger 3, an intermediate heat transfer medium 8, a low-grade cold energy recovery heat exchanger 4, normal-temperature gaseous ethylene 5, a cold delivery working fluid 6, and a cold user 7. The cryogenic liquid ethylene source 1 is used to store liquid ethylene, and the outlet of the cryogenic liquid ethylene source 1 is connected to the inlet of the ethylene pump 2. The ethylene pump 2 is used to increase the pressure of the incoming liquid ethylene to the target gasification pressure, and the outlet of the ethylene pump 2 is connected to the inlet of the first heat transfer side 191 of the intermediate heat exchanger 3. The intermediate heat exchanger 3 includes a first heat transfer side 191 and a second heat transfer side 192. The intermediate heat transfer medium 8 and the liquid ethylene exchange heat in the intermediate heat exchanger 3. The intermediate heat transfer medium 8 absorbs the high-grade cold energy of the liquid ethylene and releases cold energy in the pre-cooling heat exchanger 11, the intermediate-cooling heat exchanger 13, and the deep-cooling heat exchanger 15 to condense the oil and gas. The first heat transfer side 191 is the heat absorption side of the pressurized liquid ethylene. The inlet of the first heat transfer side 191 is connected to the outlet of the ethylene pump 2. The inlet stream of the first heat transfer side 191 is the pressurized liquid ethylene. The outlet of the first heat transfer side 191 is connected to the inlet of the third heat transfer side 193 of the low-grade cold energy recovery heat exchanger 4. The outlet stream of the first heat transfer side 191 is the intermediate-cooling gaseous ethylene. The second heat transfer side 192 is the heat release side of the intermediate heat transfer medium 8. The inlet stream of the second heat transfer side 192 is the normal-temperature intermediate heat transfer medium 8. The inlet of the second heat transfer side 192 is connected to the outlet of the sixth heat transfer side 196 of the oil and gas staged condensation recovery subsystem (oil and gas condensation recovery subsystem) 200. The outlet stream of the second heat transfer side 192 is the low-temperature intermediate heat transfer medium 8. The outlet of the second heat transfer side 192 is connected to the inlet of the tenth heat transfer side 1910 of the oil and gas staged condensation recovery subsystem (oil and gas condensation recovery subsystem) 200. The low-grade cold energy recovery heat exchanger 4 is used to recover the low-grade cold energy of ethylene. The low-grade cold energy recovery heat exchanger 4 includes a third heat transfer side 193 and a fourth heat transfer side 194. The third heat transfer side 193 is the heat absorption side of ethylene. The inlet of the third heat transfer side 193 is connected to the outlet of the first heat transfer side 191 of the intermediate heat exchanger 3. The inlet of the third heat transfer side 193 is the intermediate-cooling gaseous ethylene. The outlet of the third heat transfer side 193 is the normal-temperature gaseous ethylene 5. The fourth heat transfer side 194 is the heat release side of the cold delivery medium. The inlet stream of the fourth heat transfer side 194 is the high-temperature cold delivery medium. The outlet stream of the fourth heat transfer side 194 is the low-temperature cold delivery medium. The fourth heat transfer side 194 is connected to the cold user 7. The cold delivery medium provides cold energy to the cold user 7 after absorbing the low-grade cold energy of ethylene.

[0023] Optionally, the type of the above-mentioned ethylene pump 2 can be reciprocating, rotary, centrifugal, mixed flow, axial flow, vortex type, etc. The ethylene pump 2 can be one or more in series, parallel, or combined connection, all within the protection scope of the present invention.

[0024] Optionally, the number of the above-mentioned intermediate heat exchangers 3 can be a single-stage intermediate heat exchanger 3 or a multi-stage intermediate heat exchanger 3, both belonging to the scope of the present invention.

[0025] Optionally, the above heat exchanger type can be various tubular heat exchangers, various plate heat exchangers, various heat pipes, various direct contact heat exchangers, various regenerative heat exchangers, and the heat exchange mode of the heat exchanger is not limited. Whether it is countercurrent arrangement, co-current arrangement or other arrangement modes, they are all within the protection scope of the present invention.

[0026] Optionally, the above-mentioned cold working medium 6 can be a gaseous working medium such as pressurized air, nitrogen, or a liquid working medium such as methanol aqueous solution with any concentration, or a combination of one or more of them, which are all within the protection scope of the present invention.

[0027] Optionally, the above-mentioned cold user 7 can be various cold users 7 such as fresh food cold storage, database cooling, industrial cooling, etc., which are all within the protection scope of the present invention.

[0028] Oil and gas staged condensation recovery subsystem (oil and gas condensation recovery subsystem) 200 includes an oil and gas source 9, an oil and gas induced draft fan 10, a precooling heat exchanger 11, a precooling separator 12, an intermediate cooling heat exchanger 13, an intermediate cooling separator 14, a cryogenic heat exchanger 15, a cryogenic separator 16, an exhaust gas outlet 17, and a condensate collector 18. The oil and gas source 9 is used to store oil and gas, and the oil and gas induced draft fan 10 is used to provide the pressure for the flow of oil and gas. The outlet of the oil and gas induced draft fan 10 is connected to the inlet of the seventh heat exchange side 197 of the precooling heat exchanger 11. The function of the precooling heat exchanger 11 is to precool the oil and gas with the cold energy of the reflux low-temperature exhaust gas and the circulating intermediate heat exchange medium 8. The precooling heat exchanger 11 includes a fifth heat exchange side 195, a sixth heat exchange side 196, and a seventh heat exchange side 197. The fifth heat exchange side 195 is the heat absorption side of the reflux low-temperature exhaust gas outlet 17. The inlet of the fifth heat exchange side 195 is connected to the gas phase outlet of the cryogenic separator 16. The inlet stream of the fifth heat exchange side 195 is the low-temperature reflux exhaust gas outlet 17, and the outlet stream of the fifth heat exchange side 195 is the normal-temperature reflux exhaust gas outlet 17. The outlet of the fifth heat exchange side 195 leads to the ambient atmosphere. The sixth heat exchange side 196 is the heat absorption side of the circulating intermediate heat exchange medium 8. The inlet of the sixth heat exchange side 196 is connected to the outlet of the eighth heat exchange side 198 of the intermediate cooling heat exchanger 13. The inlet stream of the sixth heat exchange side 196 is the nearly normal-temperature intermediate heat exchange medium 8. The outlet of the sixth heat exchange side 196 is connected to the inlet of the second heat exchange side 192 of the intermediate heat exchanger 3. The outlet stream of the sixth heat exchange side 196 is the normal-temperature intermediate heat exchange medium 8. The seventh heat exchange side 197 is the precooling and condensation heat exchange side of the oil and gas. The inlet of the seventh heat exchange side 197 is connected to the outlet of the oil and gas supply fan. The inlet stream of the seventh heat exchange side 197 is the oil and gas. The outlet of the seventh heat exchange side 197 is connected to the inlet of the precooling separator 12. The outlet stream of the seventh heat exchange side 197 is the precooled gas-liquid two-phase oil and gas containing liquid organic working medium. The function of the precooling separator 12 is to separate the gas-phase oil and gas and the liquid-phase organic working medium. The precooling separator 12 includes an inlet, a gas phase outlet, and a liquid phase outlet. The inlet of the precooling separator 12 is connected to the outlet of the seventh heat exchange side 197. The gas phase outlet of the precooling separator 12 is connected to the inlet of the ninth heat exchange side 199 of the intermediate cooling heat exchanger 13. The gas phase outlet stream of the precooling separator 12 is the oil and gas from which heavier molecular weight organic working medium has been partially removed. The liquid phase outlet of the precooling separator 12 is connected to the condensate collector 18. The liquid phase outlet stream of the precooling separator 12 is the liquid-phase organic working medium mainly composed of heavier molecular weight components. The intermediate cooling heat exchanger 13 includes an eighth heat exchange side 198 and a ninth heat exchange side 199. The eighth heat exchange side 198 is the heat absorption side of the circulating intermediate heat exchange medium 8. The inlet of the eighth heat exchange side 198 is connected to the outlet of the tenth heat exchange side 1910 of the cryogenic heat exchanger 15. The inlet stream of the eighth heat exchange side 198 is the circulating intermediate heat exchange medium 8 at the intermediate cooling temperature. The outlet of the eighth heat exchange side 198 is connected to the inlet of the sixth heat exchange side 196 of the precooling heat exchanger 11. The outlet stream of the eighth heat exchange side 198 is the nearly normal-temperature intermediate heat exchange medium 8.The ninth heat exchange side 199 is the intermediate cooling and condensation heat exchange side for oil and gas. The inlet of the ninth heat exchange side 199 is connected to the gas phase outlet of the precooling heat exchanger 11. The inlet stream of the ninth heat exchange side 199 is the oil and gas from which heavier molecular weight organic working fluids have been removed and are precooled. The outlet of the ninth heat exchange side 199 is connected to the inlet of the intermediate cooling separator 14. The outlet stream of the ninth heat exchange side 199 is the gas-liquid two-phase oil and gas at the intermediate cooling temperature containing liquid organic working fluids. The function of the intermediate cooling separator 14 is to separate the gas phase oil and gas and the liquid phase organic working fluids. The intermediate cooling separator 14 includes an inlet, a gas phase outlet, and a liquid phase outlet. The inlet of the intermediate cooling separator 14 is connected to the outlet of the ninth heat exchange side 199. The gas phase outlet of the intermediate cooling separator 14 is connected to the inlet of the eleventh heat exchange side 1911 of the cryogenic heat exchanger 15. The gas phase outlet stream of the intermediate cooling separator 14 is the oil and gas at the intermediate cooling temperature from which most of the heavier molecular weight organic working fluids have been separated. The liquid phase outlet of the intermediate cooling separator 14 is connected to the condensate collector 18. The liquid phase outlet stream of the intermediate cooling separator 14 is the liquid phase organic working fluids mainly composed of heavier molecular weight components at the intermediate cooling temperature. The cryogenic heat exchanger 15 includes a tenth heat exchange side 1910 and an eleventh heat exchange side 1911. The tenth heat exchange side 1910 is the heat absorption side of the circulating intermediate heat exchange medium 8 at the cryogenic temperature. The eleventh heat exchange side 1911 is the cryogenic cooling and condensation heat exchange side for the oil and gas from which most of the heavier molecular weight organic working fluids have been separated. The inlet of the tenth heat exchange side 1910 is connected to the outlet of the second heat exchange side 192 of the intermediate heat exchanger 3. The inlet stream of the tenth heat exchange side 1910 is the intermediate heat exchange medium 8 at the cryogenic temperature. The outlet of the tenth heat exchange side 1910 is connected to the inlet of the eighth heat exchange side 198. The outlet stream of the tenth heat exchange side 1910 is the intermediate heat exchange medium 8 at the intermediate cooling temperature. The inlet of the eleventh heat exchange side 1911 is connected to the gas phase outlet of the intermediate cooling separator 14. The inlet stream of the eleventh heat exchange side 1911 is the oil and gas at the intermediate cooling temperature from which most of the heavier molecular weight organic working fluids have been separated. The outlet of the eleventh heat exchange side 1911 is connected to the inlet of the cryogenic separator 16. The outlet stream of the eleventh heat exchange side 1911 is the gas-liquid two-phase oil and gas at the cryogenic temperature containing liquid organic working fluids. The function of the cryogenic separator 16 is to separate the gas phase oil and gas and the liquid phase organic working fluids. The cryogenic separator 16 includes an inlet, a gas phase outlet, and a liquid phase outlet. The inlet of the cryogenic separator 16 is connected to the outlet of the eleventh heat exchange side 1911. The inlet stream of the cryogenic separator 16 is the gas-liquid two-phase oil and gas at the cryogenic temperature containing liquid organic working fluids. The gas phase outlet of the cryogenic separator 16 is connected to the fifth heat exchange side 195 of the precooling heat exchanger 11. The gas phase outlet stream of the cryogenic separator 16 is the cryogenic temperature waste gas that can be directly discharged and basically does not contain organic working fluids. The liquid phase outlet of the cryogenic separator 16 is connected to the condensate collector 18. The liquid phase outlet stream of the cryogenic separator 16 is the liquid phase organic working fluids containing lighter and heavier molecular weight components at the cryogenic temperature.

[0029] Optionally, the cold-carrying method in the above intermediate heat transfer medium 8 is not limited. It can not only use water, methanol, methanol aqueous solutions with any concentration, R600, R160, R290, R11, R123, R610, R601, ethanol, ethanol aqueous solutions with any concentration, isopropane, acetone and other organic, inorganic or mixed liquid-phase working fluids, or gaseous working fluids such as pressurized air and pressurized nitrogen, and combinations of one or more of them are all within the protection scope of the present invention.

[0030] The above oil and gas source 9 can be an oil and gas storage tank, and the oil and gas storage tank can be a spherical tank, a horizontal tank, a domed tank or a floating roof tank, all of which are within the protection scope of the present invention.

[0031] Optionally, the type of the above oil and gas induced draft fan 10 can be centrifugal, axial, diagonal (mixed flow) and cross-flow types, etc., all of which are within the protection scope of the present invention. The oil and gas induced draft fan 10 can be connected in series, in parallel or in a combined form with one or more units.

[0032] Optionally, the above oil and gas cooling heat exchanger is divided into a pre-cooling heat exchanger 11, an intermediate cooling heat exchanger 13 and a cryogenic heat exchanger 15, and the corresponding pre-cooling separator 12, intermediate cooling separator 14 and cryogenic separator 16 for three-stage heat exchange and separation. It can be replaced by a two-stage heat exchange and separation of the pre-cooling heat exchanger 11 and the cryogenic heat exchanger 15 and the corresponding pre-cooling separator 12 and cryogenic separator 16, or replaced by a one-stage heat exchange and separation of the cryogenic heat exchanger 15 and the cryogenic separator 16, all of which are within the protection scope of the present invention.

[0033] Optionally, the type of the above gas-liquid separator can be microporous filtration separation, wire mesh separation, packing separation, centrifugal separation, baffle separation (baffle separation) or gravity sedimentation separation, etc., and combinations of one or more of them are all within the protection scope of the present invention.

[0034] Optionally, the low-temperature waste gas discharged from the gas phase outlet of the above cryogenic separator 16 recovers cold energy by exchanging heat in the pre-cooling separator 12, and can be replaced by exchanging heat in the pre-cooling separator 12 and the intermediate cooling heat exchanger 13 to recover cold energy, or exchanging heat in the pre-cooling separator 12, the intermediate cooling heat exchanger 13 and the cryogenic heat exchanger 15 to recover cold energy, or in a combined form based on the above methods, all of which are within the protection scope of the present invention.

[0035] The process flow of an ethylene gasification heat utilization system provided by the present invention is as follows:

[0036] The cryogenic liquid ethylene in the cryogenic liquid ethylene source 1 is pressurized by the ethylene pump 2 and sent to the intermediate heat exchanger 3. The cryogenic liquid ethylene exchanges heat with the intermediate heat exchange medium 8 in the intermediate heat exchanger 3. The ethylene releases high-grade cold energy and gasifies and heats up, while the intermediate heat exchange medium 8 absorbs the cold energy and cools down to a low temperature state. Part of the warmed intermediate-cooled gaseous ethylene releases low-grade cold energy through heat exchange with the cold energy recovery heat exchanger 4 and the cold delivery working fluid 6. After that, the normal-temperature gaseous ethylene 5 heated up to normal temperature is sent to ethylene users through the ethylene pipeline network. And the cold delivery working fluid 6 that has absorbed the low-grade cold energy of ethylene is sent to the cold user 77 to release cold energy. The intermediate heat exchange medium 8 cooled to a low temperature by the liquid ethylene gradually passes through the cryogenic heat exchanger 15, the intermediate-cooled heat exchanger 13, and the precooling heat exchanger 11 to release cold energy to cool the oil and gas, and then returns to the intermediate heat exchanger 3 to absorb the cold energy of the re-gasification of the liquid ethylene again. The oil and gas in the oil and gas source 9 is pressurized and transported to the precooling heat exchanger 11 by the oil and gas induced draft fan 10. Then, after being cooled by the intermediate heat exchange medium 8 and the reflux cryogenic exhaust gas, the precooled oil and gas is subjected to gas-liquid separation by the precooling separator 12. Among them, the condensed liquid-phase organic working medium separated out is introduced into the condensate collector 18, and the gaseous oil and gas separated out is introduced into the intermediate-cooled heat exchanger 13 to further absorb the cold energy of the intermediate heat exchange medium 8 and be cooled to an intermediate-cooled state. Then, the intermediate-cooled oil and gas is subjected to gas-liquid separation by the intermediate-cooled separator 14. Among them, the condensed liquid-phase organic working medium separated out by the intermediate-cooled separator 14 is introduced into the condensate collector 18, and the gaseous oil and gas separated out by the intermediate-cooled separator 14 is introduced into the cryogenic heat exchanger 15 to be cooled to a cryogenic state. Then, the cryogenic oil and gas cooled by the cryogenic heat exchanger 15 is introduced into the cryogenic separator 16 for gas-liquid separation. The condensed liquid-phase organic working medium separated out by the cryogenic separator 16 is introduced into the condensate collector 18, and the cryogenic exhaust gas containing almost no organic working medium separated out by the cryogenic separator 16 flows back to the precooling heat exchanger 11 to recover cold energy to cool the incoming oil and gas. Due to the high degree of separation, the content of the organic working medium in the gaseous exhaust gas of the cryogenic separator 16 has reached the standard. Therefore, the reflux exhaust gas 17 after releasing the cold energy is directly discharged into the atmosphere.

[0037] Compared with the prior art, the advantages of an ethylene gasification heat utilization system provided by the present invention are as follows:

[0038] The ethylene gasification heat utilization system of the present invention avoids the disadvantages such as economic loss of organic working medium, exhaust pollution, and high energy consumption in direct combustion treatment, and adopts the recovery method to condense and recover the organic working medium to obtain better economy.

[0039] The ethylene gasification heat utilization system of the present invention innovatively introduces the re-gasification waste cold of liquid ethylene, replaces the refrigerating machine in the traditional condensation recovery process, and saves the electricity cost for driving the refrigerating machine.

[0040] The ethylene gasification heat utilization system of the present invention provides a high-value cold energy utilization method for the waste cold of the regasification of liquid ethylene, eliminates the cost of purchasing a large amount of thermal steam for heating and gasifying ethylene, and improves economic benefits.

[0041] The ethylene gasification heat utilization system of the present invention uses an intermediate heat exchange medium 8 to absorb the cold energy of liquid ethylene all-weather, ensuring the uninterrupted gasification of liquid ethylene and the supply to ethylene users. Moreover, the liquid ethylene does not enter the internal oil and gas system, eliminating the potential safety risk of combustion and explosion of ethylene and oil and gas.

[0042] The cold energy introduced by the ethylene gasification heat utilization system of the present invention comes from liquid ethylene, which is common in chemical industrial parks, easy to obtain, and has extremely low additional transportation costs.

[0043] The ethylene gasification heat utilization system of the present invention reasonably utilizes the low-grade cold energy of ethylene to supply cold users 7, realizes the cascade utilization of cold energy, and avoids the waste of cold energy.

[0044] The ethylene gasification heat utilization system proposed by the present invention uses a circulating intermediate heat exchange medium 8 to absorb the waste cold of the regasification of liquid ethylene all-weather and use it for the condensation process of oil and gas, ensuring the uninterrupted gasification of liquid ethylene and eliminating the combustion and explosion risk of direct heat exchange between ethylene and air.

[0045] The gas-phase exhaust of the final-stage deep cold separator 16 of the ethylene gasification heat utilization system of the present invention flows back through the oil and gas cooling heat exchanger to further recover cold energy.

[0046] Although the present invention has been described with reference to several exemplary embodiments, it should be understood that the terms used are illustrative and exemplary, rather than restrictive. Since the present invention can be embodied in many forms without departing from the spirit or essence of the invention, it should be understood that the above-described embodiments are not limited to any of the foregoing details, but should be broadly construed within the spirit and scope defined by the appended claims. Therefore, all changes and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. An ethylene gasification heat utilization system, characterized in that, It includes an ethylene gasification subsystem and an oil-gas condensation recovery subsystem that is heat-transfer connected to the ethylene gasification subsystem. When the ethylene gasification subsystem gasifies ethylene, it absorbs the heat of the oil-gas in the oil-gas condensation recovery subsystem, cooling the oil-gas to form a liquid-phase organic working medium and waste gas. Among them, the oil-gas condensation recovery subsystem includes an oil-gas source, a heat exchange component, a gas-liquid separator, and a condensate collector. The heat exchange component is connected to the ethylene gasification subsystem. The oil-gas from the oil-gas source is introduced into the heat exchange component. The ethylene gasification subsystem absorbs the heat of the oil-gas through the heat exchange component to cool the oil-gas. The cooled oil-gas is subjected to gas-liquid separation by the gas-liquid separator. The condensed liquid-phase organic working medium separated is introduced into the condensate collector, and the separated waste gas is discharged into the atmosphere.

2. The ethylene gasification heat utilization system according to claim 1, wherein The ethylene gasification subsystem includes an ethylene source and an intermediate heat exchanger. The intermediate heat exchanger has a first heat exchange side and a second heat exchange side. The ethylene source is connected to the input end of the first heat exchange side. The heat exchange component is connected to the input end and the output end of the second heat exchange side through pipelines. The heat exchange component and the second heat exchange side form a first circulation loop, and an intermediate heat exchange medium circulates in the first circulation loop. When liquid ethylene is introduced into the intermediate heat exchanger, the intermediate heat exchange medium exchanges heat with the liquid ethylene in the intermediate heat exchanger, gasifying the liquid ethylene and releasing high-grade cold energy. The intermediate heat exchange medium absorbs the cold energy and cools down to a low temperature state. The intermediate heat exchange medium in the low temperature state is introduced into the heat exchange component to exchange heat with the oil-gas, cooling the oil-gas. After heat exchange, the liquid ethylene is transformed into gaseous ethylene, and the gaseous ethylene is output outward through the output end of the first heat exchange side.

3. The ethylene gasification heat utilization system according to claim 2, characterized in that The heat exchange component includes a cryogenic heat exchanger and an intermediate heat exchanger connected in series. The intermediate heat exchange medium cooled to a low temperature state sequentially passes through the cryogenic heat exchanger and the intermediate heat exchanger. The oil-gas from the oil-gas source is sequentially transported to the intermediate heat exchanger and the cryogenic heat exchanger through pressurization.

4. The ethylene gasification heat utilization system according to claim 3, wherein, It also includes a pre-cooling heat exchanger connected in series with the cryogenic heat exchanger and the intermediate heat exchanger. The intermediate heat exchange medium cooled to a low temperature state sequentially passes through the cryogenic heat exchanger, the intermediate heat exchanger, and the pre-cooling heat exchanger. The oil-gas from the oil-gas source is sequentially transported to the pre-cooling heat exchanger, the intermediate heat exchanger, and the cryogenic heat exchanger through pressurization.

5. The ethylene gasification heat utilization system according to claim 3, characterized in that, The gas-liquid separator includes a cryogenic separator and an intermediate separator. The oil-gas cooled by the intermediate separator enters the intermediate separator for gas-liquid separation. The separated liquid-phase organic working medium is introduced into the condensate collector. The separated gaseous oil-gas enters the cryogenic heat exchanger and is cooled to a cryogenic state by the cryogenic heat exchanger. The oil-gas in the cryogenic state enters the cryogenic separator for gas-liquid separation. The separated liquid-phase organic working medium is introduced into the condensate collector, and the separated waste gas is discharged into the atmosphere.

6. The ethylene gasification heat utilization system according to claim 4, characterized in that, The gas-liquid separator includes a cryogenic separator, an intermediate separator, and a pre-cooling separator. The oil-gas cooled by the pre-cooling separator enters the pre-cooling separator for gas-liquid separation. The separated liquid-phase organic working medium is introduced into the condensate collector. The separated gaseous oil-gas enters the intermediate separator. The oil-gas cooled by the intermediate separator enters the intermediate separator for gas-liquid separation. The separated liquid-phase organic working medium is introduced into the condensate collector. The separated gaseous oil-gas enters the cryogenic heat exchanger and is cooled to a cryogenic state by the cryogenic heat exchanger. The oil-gas in the cryogenic state enters the cryogenic separator for gas-liquid separation. The separated liquid-phase organic working medium is introduced into the condensate collector, and the separated waste gas is discharged into the atmosphere.

7. The ethylene gasification heat utilization system according to claim 6, characterized in that, The waste gas separated by the cryogenic separator is introduced into the pre-cooling heat exchanger, where the waste gas exchanges heat with the oil and gas. After the waste gas releases the remaining cold energy, it is discharged into the atmosphere through the pre-cooling heat exchanger.

8. The ethylene gasification heat utilization system according to claim 2, characterized in that It also includes a low-grade cold energy heat exchanger and a cold user. The low-grade cold energy heat exchanger is connected to the first heat exchange side pipeline of the intermediate heat exchanger. The medium-cooled gaseous ethylene is introduced into the low-grade cold energy heat exchanger, where the medium-cooled gaseous ethylene exchanges heat with the cold user through the low-grade cold energy heat exchanger to release low-grade cold energy. After heat exchange, the medium-cooled gaseous ethylene is heated to normal temperature gaseous ethylene.

9. The ethylene gasification heat utilization system according to claim 4, characterized in that, The low-grade cold energy heat exchanger has a third heat exchange side and a fourth heat exchange side. The output end of the first heat exchange side of the intermediate heat exchanger is connected to the input end of the third heat exchange side through a pipeline. The cold user is connected to the output end and the input end of the fourth heat exchange side through pipelines. The cold user and the fourth heat exchange side form a second circulation loop, and a cold delivery working medium circulates inside the second circulation loop.

10. The ethylene gasification heat utilization system according to claim 2, characterized in that, It also includes an ethylene pump. The input end of the ethylene pump is connected to the ethylene source through a pipeline, and the output end of the ethylene pump is connected to the input end of the first heat exchange side through a pipeline. The ethylene pump drives the liquid ethylene to flow towards the intermediate heat exchanger, raising the pressure of the liquid ethylene to the target vaporization pressure.

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