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JP-7855529-B2 - System and method for selective extraction of viscous hydrocarbons from tanks and other containers

JP7855529B2JP 7855529 B2JP7855529 B2JP 7855529B2JP-7855529-B2

Inventors

  • フォンテチャ クエトス，エヴァリスト

Assignees

  • フォンテチャ クエトス，エヴァリスト
  • カレレス イ アソシアドス ゲストラ エン インモビラリア イ メディオ アンビエンテ エスエル

Dates

Publication Date
20260508
Application Date
20210602
Priority Date
20200603

Claims (14)

  1. A system for extracting viscous hydrocarbons from storage tanks and other containers, - A steam boiler (4) having control means configured to adjust the amount and temperature of the steam it supplies, wherein the temperature of the supplied water is between 120 and 200°C, - An apparatus for homogenizing the steam supplied by the steam boiler with a gas flow configured to recirculate gas from the steam boiler itself, injecting the resulting homogeneous gas mixture into the tank or container (1), and heating the surface layer of the extracted hydrocarbon, - At least one first pump (7) for selectively extracting the hydrocarbons from the surface layer heated by an injected homogeneous gas mixture, wherein the first pump (7) has a first pump suction duct (7a) connected in a peripheral region to the tank or container (1) for extracting the heated hydrocarbons from the surface layer therein. It has, The apparatus for homogenizing the gas flow and injecting it into the tank or container (1) comprises at least one steam ejector (3) arranged to provide vortex diffusion of the driving steam supplied by the steam boiler (4) and the recirculated gas from the tank or container (1), wherein the steam ejector (3) - The driving steam connected to the steam boiler (4), - A vapor ejector gas intake duct (3a) connected to a point in the tank or container (1) on the surface layer of the hydrocarbon to be extracted, - A steam ejector gas discharge duct (3b) through which the homogeneous gas mixture is injected into the tank or container (1). The diffuser of the steam ejector (3) has a vortex diffusion that occurs in the diffuser of the steam ejector (3) of the driving steam supplied by the steam boiler (4) and the gas that the steam ejector (3) draws in through the steam ejector gas intake duct (3a) by the Venturi effect, gas arriving from the tank or container (1) itself, from the atmosphere, from the steam boiler (4), or a combination thereof, and at the discharge port of the steam ejector gas discharge duct (3b) of the steam ejector (3), the homogeneous mixture of high-temperature gas obtained as a result of the vortex diffusion is injected into the tank or container (1) to heat the surface layer of hydrocarbons. As a result, such vortex diffusion prevents the steam injected into the tank or container (1) from moving freely upward, and consequently, most of the injected driving steam condenses on the surface layer of the hydrocarbon, and its latent heat is transferred to the surface layer. A system characterized by the following features.
  2. - A peripheral conduit (5) externally attached to a portion of the metal wall of the tank or container (1) located below a level determined by the hydrocarbon being extracted, for the purpose of localized heating of the hydrocarbon, wherein a portion of the peripheral conduit (5) is made up of the portion of the metal wall of the tank or container (1) to which it is attached, and the high-temperature gas circulating through the peripheral conduit (5) comes into direct contact with the portion of the metal wall, thereby locally heating the hydrocarbon adjacent to the tank or container (1), - At least one second pump (8) for extracting sediment from the tank or container (1), wherein the first pump suction duct (7a) and the second pump suction duct (8a) are connected to the tank or container (1) in a peripheral region close to the region heated by the peripheral conduit (5), - The system according to claim 1, further comprising a gas duct connected to two different points around the tank or container (1) which are located above a level determined by the hydrocarbons being extracted, wherein at least one of the two different points of the gas duct of the ejector is in close proximity to the surrounding area.
  3. The system according to claim 2, wherein the first pump suction duct (7a) is connected at one end to an oil suction device (7c) with its suction opening directed upward, and the second pump suction duct (8a) is connected at one end to a sediment water suction device (8c) with its suction opening directed toward the bottom of the tank or container.
  4. The system according to claim 2, wherein the surrounding conduit (5) is made of a synthetic fiber cover supported by semicircular arches distributed along the entire length of the surrounding conduit (5), thereby obtaining a semi-cylindrical shape having a flat portion that matches the portion of the metal wall of the tank or container (1) to which it is attached and sealed by two straps, and the semicircular arches have support plates at their two ends having rings welded to them for guiding and holding the two straps passing through them.
  5. The system according to claim 4, wherein the high-temperature gas circulating through the surrounding conduit (5) is supplied by a second steam ejector (6), the gas discharge opening of which is connected to an inlet opening for the high-temperature gas in the surrounding conduit (5), the driving steam nozzle of which is connected to the steam boiler (4), and the gas intake opening of which draws in air from the atmosphere by the Venturi effect, thereby homogeneously mixing the inhaled air with the driving steam and injecting it into the inlet opening for the high-temperature gas in the surrounding conduit (5) by the second steam ejector (6) itself.
  6. The system according to claim 1, wherein the steam ejector gas intake duct (3a) has within it at least one gas circulator configured to increase the flow rate of gas that the steam ejector (3) injects into the tank or container (1).
  7. The system according to claim 1, wherein the steam ejector gas intake duct (3a) has at least one connection point therein for injecting another steam ejector or depressurized steam.
  8. A system according to any one of claims 1 to 7, configured to process hydrocarbons having a flash point of 55°C or higher, which are Class C and Class D hydrocarbons.
  9. It is configured to process Class B hydrocarbons with a flash point below 55°C. The system according to any one of claims 1 to 7, wherein the vapor ejector gas intake duct (3a) for injecting the gas into the tank or container (1) is connected to a nitrogen tank having a control means configured to adjust the amount of nitrogen supplied.
  10. A method for extracting viscous hydrocarbons from storage tanks and other containers, particularly tanks or containers (1) having a floating roof and metal walls, - A steam ejector (3) connected to a steam boiler (4) that supplies steam at a temperature of 120 to 200°C heats the surface layer of the hydrocarbon to be extracted. - The steam ejector (3) draws in gas arriving from the tank or container (1) itself, from the atmosphere, from the steam boiler (4), or a combination thereof, through its intake opening using the Venturi effect. - The steps of vortex-diffusing the aspirated gas with the driving steam supplied by the steam boiler (4), - A step of injecting the resulting homogeneous mixture of high-temperature gas into another point in the tank or container (1), A method comprising the step of adjusting the amount of steam supplied to the steam ejector (3) to produce a selective flow of high-temperature hydrocarbons for selective extraction of hydrocarbons from the surface layer to the first pump suction duct (7a) of the first pump (7).
  11. - An operation in which a high-temperature gas circulates in a tank or container (1) through a peripheral conduit (5) externally attached to the tank or container (1) to locally heat the hydrocarbons selectively flowing from the surface layer, wherein during extraction, sedimentation of non-emulsified water occurs, and a selective flow of heated hydrocarbons is generated by the peripheral conduit (5) toward an oil suction device (7c) connected to a first pump (7) for selective extraction of hydrocarbons by a first pump suction duct (7a), and The method according to claim 10, further comprising the operation of selectively extracting hydrocarbons heated by a surrounding conduit (5) using a first pump (7), and periodic extraction of precipitated water using a second pump (8), wherein the first pump suction duct (7a) is connected at one end to an oil suction device (7c) with its suction port facing upward, and the second pump suction duct (8a) is connected at one end to a precipitated water suction device (8c) with its suction port facing the bottom of the tank or container (1).
  12. The method according to claim 11, wherein the high-temperature gas circulating through the surrounding conduit (5) is supplied by a second steam ejector (6), the gas discharge opening (6b) of which is connected to an inlet opening for the high-temperature gas in the surrounding conduit (5), the driving steam nozzle of which is connected to the steam boiler (4), and the gas suction opening of which draws in air from the atmosphere by the Venturi effect, thereby homogeneously mixing the drawn air with the driving steam and injecting it into the inlet opening for the gas in the surrounding conduit (5) by the second steam ejector (6) itself.
  13. A method according to any one of claims 10 to 12, used for processing Class C and Class D hydrocarbons having a flash point of 55°C or higher.
  14. - The operation of initial nitrogen injection from the nitrogen tank (9) to the tank or container (1) until the oxygen concentration reaches less than 8%, The method according to any one of claims 10 to 12, further comprising the operation of a controlled supply of nitrogen to keep the oxygen concentration in the tank or container (1) always below 8%, for use in processing a Class B hydrocarbon with a flash point below 55°C.

Description

This invention relates to a system and method for selectively extracting viscous hydrocarbons from storage tanks and other containers that must be periodically emptied and cleaned for periodic inspection, repair, load changes, dismantling, etc. The system and method of the present invention are applicable to storage tanks and other containers containing viscous hydrocarbons found in oil refineries, petrochemical plants, thermal power plants, port terminals, and the like. A floating-roof (or floating-roof type) oil tank and hydrocarbon process unit, including a distillation column, reactor, fan cooler, container having a gaseous hydrocarbon "demister," and interconnecting pipes, constitutes a typical example of the application of the present invention. Among the viscous hydrocarbons to which this system and selective extraction method can be applied, the hydrocarbons that accumulate at the bottom of oil tanks (Class B, flash point < 55°C), heavy oil (Class C, flash point between 55°C and 100°C), and asphalt (Class D, flash point > 100°C) must be identified. US3874399A discloses a method for discharging high-viscosity hydrocarbons from a tank by recirculating preheated discharge hydrocarbons within the tank to reduce the viscosity of the tank's contents and facilitate their discharge. ES417373A1 describes a method for purging combustible waste from a container, comprising passing a gas stream containing water vapor and an inert gas such as nitrogen through the container, wherein the gas stream introduced into the container has a water vapor content of 4-50% by volume and introduces enough heat into the container to reach a temperature of at least 50°C. U.S. Patent Application Publication No. 5085242A discloses a method and apparatus for removing residue from a storage tank by locally heating the tank with steam, water vapor, or electricity and introducing hydrocarbons into the heated area. GB2101475A describes a method of cleaning a storage tank with sludge by bringing it into contact with hot water (hot water injection and recirculation). This process reaches 70°C, reducing viscosity and allowing for the removal of residual material. ES2391183B1 (P201100464), belonging to the same inventors as the present application, discloses a method for selectively extracting high-viscosity hydrocarbons using the following steps: applying safety measures (measuring the explosiveness inside the tank for a floating-roof oil tank); heating the contents of the tank with a flexible coil slightly immersed in hydrocarbons; and heating the surface layer of hydrocarbons by injecting hot air into the tank. Similarly, ES2544575B1 (P201400060), belonging to the same inventors as this application, discloses a method for the selective extraction of residual viscous hydrocarbons in a storage tank. This method includes measuring the explosiveness of the tank, heating the hydrocarbons with a device placed inside the tank, and heating the surface of the hydrocarbons by injecting hot air. As a further step, after the hydrocarbon extraction and the maintenance of hot air injection, hot water is injected onto the residual hydrocarbons to facilitate subsequent extraction. Patent document WO2017118766A1 (P201600007), belonging to the same inventors as this application, discloses a method for extracting viscous hydrocarbons from a tank by injecting a flow of hot air and steam into the tank. A centrifugal fan or gas circulator is used for injection, passing the flow through an electric heater equipped with a deflector that generates a vortex. This heats the air, absorbs moisture into the air, superheats the steam, and extracts the hydrocarbons. Furthermore, the hydrocarbons can be further heated by a device for local heating near the intake pipe. Patent document WO2019197690 (P201800095), belonging to the same inventors as this application, describes a method for extracting viscous hydrocarbons from storage tanks and process equipment. This method proposes injecting an inert gas into a portion of the tank or equipment until an oxygen concentration is achieved that guarantees a range of zero flammability; and then injecting a gas stream homogenized by an irreversible vortex diffusion process into the tank or equipment. This gas stream consists of gas recirculated from the tank or equipment, and amounts of water vapor and inert gas always required to maintain the oxygen concentration at a value that guarantees a range of flammability and to deliver hydrocarbons in an amount equivalent to that required by an extraction pump suitable for use in potentially explosive atmospheres. Utility Model No. RU25176U discloses a device for washing viscous oil and sediment of petroleum products from a tank or for washing sediment, the device comprising means for heating, liquefying, moving, and mixing the sediment, the sediment comprising a hollow bar through which steam, gas, or liquid circulates, the hollow bar positioned above the bottom of the sediment and c