Crude oil heat treatment apparatus, system and method

Abstract

A heating system, apparatus, and method for the heat treatment of crude oil including a heat exchanger having a plurality of heat exchanger tubes and an electric immersion vacuum steam heating system external to and fluidically coupled to the heat exchanger for providing a steam portion to the heat exchanger. The external electric immersion vacuum steam heating system includes a steam boiler enclosing an electric immersion element configured for generating, under vacuum or negative pressure, the steam portion having a first steam temperature lower than the 212° F. when power is selectively supplied to the electric immersion element immersed in water contained within the steam boiler. The heat exchanger is configured for transferring heat energy released from condensation of the steam portion to the crude oil via the plurality of heat exchanger tubes.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from U.S. Provisional Patent application No. 63 / 470,481 filed Jun. 2, 2023 titled CRUDE OIL HEAT TREATMENT APPARATUS, SYSTEM AND METHOD, which application is fully incorporated herein by reference.TECHNICAL FIELD

[0002] The present invention relates to the heat treatment of crude oil prior to its transport and further processing and more particularly, to the heat treatment of crude oil using a tubular heat exchanger, where steam is supplied from an external heat source including an electric immersion element.BACKGROUND INFORMATION

[0003] Crude oil requires treatment including the separation of water, sediment, and gas from the crude oil prior to transport or further use or processing of the crude oil. Typically, such treatment takes place at a location which is fed from a single or multiple oil wells. The crude oil or oil emulsion must be sufficiently treated to meet regulatory requirements including basic sediment and water standards, and vapor pressure requirements. The application of heat to the crude oil aids in the separation of water and sediment. Heating the crude oil also lowers the fluid vapor pressure by removing the free gas along with light ends components which are boiled off. Heating promotes the more volatile components in the crude oil to vaporize, exit the fluid and lowers the remaining fluid vapor pressure to the required value deemed safe for transport in for example, trucks, railcars, and pipelines.

[0004] Firetube heating systems have traditionally been used for such crude oil treatment. Traditional firetube heating systems include a heater treater vessel containing a water portion and a crude oil portion floating on the water portion. The heater treater vessel includes a generally u-shaped firetube which is submerged in the water portion of the heater treater vessel and is coupled to a gas fired burner disposed outside of the heater treater vessel. When fired, the burner projects a flame into the firetube. The flame directly impinges upon the surrounding firetube walls and heat is transferred from the gas flame to the walls of the firetube via radiant and convective heat transfer. Heat energy is then transferred via conduction and convection through the firetube to the water portion surrounding the firetube, and from the water portion to the crude oil portion at the oil / water interface through convective heat transfer.

[0005] The traditional firetube heating system operates at a heat transfer efficiency in a range of 70% to 85% and sometimes as low as 40%-45%. The low heat transfer efficiency of firetube heating systems means more fuel gas must be burned to raise the temperature of the crude oil to achieve the target oil quality and thus greater greenhouse gas emissions.

[0006] The relatively low heat transfer firetube heating system efficiency is due in part to the relatively inefficient heat transfer at the oil / water interface which relies upon the water portion to transfer heat to the oil portion through the water-oil boundary layer. In addition, heat loss occurs when hot combustion gases must be vented to the atmosphere and not all the heat generated by the flame is transferred to or absorbed by the firetube walls or the surrounding water portion. The heat transfer efficiency decreases over time when oil impurities and minerals become entrained in the water portion and build up or scale onto the firetube and other elements of the firetube heating system. Scaling may be exacerbated if / when the metal of the firetube becomes overheated and the water portion surrounding the firetube boils.

[0007] The direct contact of boiling water with the exterior firetube surface leads to further surface scaling where minerals from the water are deposited on the firetube exterior surface as the water changes from a liquid to a vapor phase. The mineral deposits accumulate over time, and such accumulation insulates or fouls the firetube exterior surface further decreasing effective heat transfer. Periodic cleaning of the scaled material or repair or replacement of the scaled system elements results in lost production time and increased production costs.

[0008] The continued accumulation of mineral scale deposits on the exterior surface of the firetube also leads to a potential for firetube overheating and the burning of corrosion inhibition coatings from the firetube exterior surface. With diminished or removed protection coatings, the firetube inevitably corrodes over time. Continued overheating may weaken the firetube to a point where the firetube will no longer support the pressures exerted on the firetube by the fluids contained in the heater treater vessel. The firetube may eventually rupture which may allow the oil and water mixture to contact directly the burner flame ending in a potentially catastrophic failure including environmental damage, fire or explosion, equipment and production losses and possibly even loss of human life.

[0009] The regulatory environment's movement towards increasingly stringent regulations which require lower vapor pressures for crude oil means that the conventional firetube heating systems must be fired for increasingly longer time periods in order to meet regulations, and the longer firing time periods increases the potential for firetube failure. Although the oil / water interface may be maintained at a level above the firetube as a mitigative safety effort, the firetube heating system design including water contact with the firetube contributes to mineral deposit scaling as discussed above, and such scaling lowers heat transfer efficiencies.

[0010] Thus, there is a need for safer, more energy efficient, and more environmentally protective apparatus, systems and methods for crude oil heat treatment. There is a particular need for the elimination of the potential risks and hazards associated with the traditional firetube heating systems for crude oil treatment and their potential for an oil-open flame direct path in the event of a firetube failure.SUMMARY OF THE INVENTION

[0011] The invention features crude oil heating apparatus, systems and methods for heating crude oil to achieve quality standards and regulatory requirements associated with crude oil transport and / or further processing. The crude oil heating system includes tubular heat exchangers configured for transferring heat energy from low temperature steam to crude oil. The low temperature steam is provided from an external steam source fluidically coupled to the tubular heat exchangers. The external steam source includes an electric immersion vacuum steam heating system configured for generating, under vacuum or negative pressure, steam at a temperature below the 212° F. boiling point temperature of water at atmospheric pressure.

[0012] The electric immersion vacuum steam heating system includes an electric immersion element configured for immersion into a surrounding water solution for heating the water solution to form steam under a vacuum or negative pressure. The crude oil heating system includes a control and monitoring system which enables control of the temperature of the steam through the control of the pressure in the electric immersion vacuum steam heating system. Corrosion in the crude oil heating system is minimized through the use of low temperature steam from an external steam source and the configuration of a closed or sealed system which uses a water solution including demineralized water.

[0013] The invention features an in-vessel heating system including a tubular heat exchanger fluidically coupled to an external electric immersion vacuum steam heating system. After heating in the heat exchanger, the heated crude oil is separated into a purified oil portion and a water-sediment-impurities portion within the same heating vessel in which the tubular heat exchanger is disposed.

[0014] The invention also features an in-line heating system where the tubular heat exchanger includes a shell and tube heat exchanger fluidically coupled to an external electric immersion vacuum steam heating system. After heating in the heat exchanger, the heated crude oil is directed into a subsequent separator or other processing vessel where the heated crude oil is separated into a purified oil portion and a water-sediment-impurities portion.

[0015] The crude oil heating system further features an electric immersion vacuum steam heating system, where the steam boiler is configured for producing, under vacuum or negative pressure, a first steam portion having a first steam temperature and subsequently, a second steam portion having a second steam temperature higher than the first steam temperature under a positive pressure. The first and the subsequent second steam portions are provided sequentially to a tubular heat exchanger. In one non-limiting embodiment, the tubular heat exchanger includes a shell and tube heat exchanger characteristic of an in-line heating system. In other non-limiting embodiments, the tubular heat exchanger includes a heat exchanger characteristic of an in-vessel heating system.

[0016] The inventive systems, apparatus and methods are safer than those of traditional firetube heating systems because the external steam source eliminates the potential for a direct path between the heat source for steam generation and the crude oil. The electric immersion vacuum steam heating system is more energy efficient than a traditional firetube heating system because the electrical element is inserted into and heats directly the surrounding water solution in contrast to traditional firetubes which rely on radiant and convective heat energy transfer from the flame to the firetube walls and conductive heat energy transfer therethrough. The burning of corrosion protective coatings from the heat exchanger tubes and the buildup of mineral scaling is minimized through the use of low temperature steam which does not result in water boiling and associated mineral deposit and scaling on the heat exchanger tubes. Mineral deposit scaling is also reduced through the configuration of a closed or sealed crude oil heating system which uses demineralized water. The crude oil heating system represents environmental protection advantages because the electric immersion element is a zero emissions source.

[0017] For purposes of the present application, term “heat duty” refers to the heat required added or removed from the process fluids to create the required change in temperature. It can be in the form of sensible heat, latent heat, or latent heat of vaporization; and

[0018] the phrase “heat transfer efficiency” refers to the percentage ratio of the amount of heat energy actually transferred to the amount of heat energy available for transfer from a first fluid to a second fluid.

[0019] In one embodiment, the invention features a heating system for the heat treatment of a crude oil portion. The heating system includes a heat exchanger including a plurality of heat exchanger tubes. The heating system also includes an electric immersion vacuum steam heating system external to and fluidically coupled to the heat exchanger and configured for providing the steam portion to the heat exchanger. The electric immersion vacuum steam heating system includes a steam boiler enclosing an electric immersion element and a first water portion, the electric immersion vacuum steam heating system being configured for generating, under vacuum or negative pressure, the steam portion having a steam temperature lower than the 212° F. when power is selectively supplied to the electric immersion element immersed in the first water portion contained within the steam boiler. The heat exchanger is configured for transferring heat energy released from condensation of the steam portion to the crude oil portion via the plurality of heat exchanger tubes.

[0020] In an embodiment, the crude oil heating system is configured such that the steam portion provided to the heat exchanger has a steam temperature in a range of 78° F. to 210° F.

[0021] In another embodiment, the heating system is configured enabling the crude oil portion to reach a heated oil temperature in a range of 100° F. to 150° F. after heat energy released from condensation of the steam portion is transferred to the crude oil portion via the plurality of heat exchanger tubes.

[0022] In yet another embodiment, the electric immersion vacuum steam heating system is configured for drawing a vacuum in a negative pressure range of −27 inches mercury gauge to −29 inches mercury gauge prior to sealing of the electric immersion vacuum steam heating system.

[0023] In a further embodiment, the electric immersion vacuum steam heating system is a closed system where no additional water is added to the system after the first water portion is supplied.

[0024] In yet a further embodiment, the first water portion includes demineralized water.

[0025] In an additional embodiment, a heat transfer efficiency of the electric immersion vacuum steam heating system is in a range of 80% to 98%.

[0026] In yet another additional embodiment, the steam boiler includes a vacuum boiler constructed in accordance with corresponding then current ASME standards.

[0027] In an embodiment, the heat exchanger is configured for receiving the steam portion inside the plurality of heat exchanger tubes and for the heat exchanger tubes being surrounded by the crude oil portion.

[0028] In a further embodiment, the heat exchanger is disposed in a heating vessel being configured for separation of the crude oil portion into a purified oil portion and a separated water portion optionally including sediment and / or other impurities after heat energy released from condensation of the steam portion is transferred to the crude oil portion.

[0029] In another embodiment, the heating system is configured such that a surface temperature of an exterior surface of each of the plurality of heat exchanger tubes is below a boiling temperature of water at an operating pressure of the heating vessel.

[0030] In yet another embodiment, each of the plurality of heat exchanger tubes has an exterior surface having at least a partial coating protective against corrosion, said partial coating having a coating working temperature. The heating system is configured such that an exterior surface temperature of each of the plurality of heat exchanger tubes at an operating pressure of the heating vessel is below the coating working temperature.

[0031] In an embodiment, the heat exchanger is configured for receiving the crude oil portion inside the plurality of heat exchanger tubes. The heat exchanger includes a shell having a shell internal volume enclosing the plurality of heat exchanger tubes. The heat exchanger is configured for receiving the steam portion inside the shell internal volume surrounding the plurality of heat exchanger tubes.

[0032] In a further embodiment, after heat energy released from condensation of the steam portion is transferred to the crude oil portion, the heating system is configured for delivery of the crude oil portion from the plurality of heat exchanger tubes to a separator vessel configured for separation of the crude oil portion into a purified oil portion and a separated water portion optionally including sediment and / or impurities.

[0033] In another embodiment, the heating system is configured such that a surface temperature of an interior surface of each of the plurality of heat exchanger tubes is below a boiling temperature of water at an operating pressure within the plurality of heat exchanger tubes.

[0034] In a further embodiment, the steam portion having the steam temperature includes a first steam portion having a first steam temperature lower than 212° F. The electric immersion vacuum steam heating system is configured for generating, a second steam portion having a second steam temperature higher than the first steam temperature under positive pressure. After heat energy released from condensation of the first steam portion is transferred to the crude oil portion, the electric immersion vacuum steam heating system is configured for providing the second steam portion to the shell internal volume and transferring heat energy released from condensation of the second steam portion to the crude oil portion via the plurality of heat exchanger tubes.

[0035] In an embodiment, the invention features a method for heating a crude oil portion. The method includes providing a heat exchanger having a plurality of heat exchanger tubes; and providing an electric immersion vacuum steam heating system external to and fluidically coupled to the heat exchanger, the electric immersion vacuum steam heating system including a steam boiler configured for enclosing an electric immersion element and a first water portion. The method includes generating, under vacuum or negative pressure, a steam portion having a steam temperature lower than the 212° F. when power is selectively supplied to the electric immersion element immersed in the first water portion contained within the steam boiler. The method also includes providing the steam portion to the heat exchanger; and transferring heat energy released from condensation of the steam portion to the crude oil portion via the plurality of heat exchanger tubes.

[0036] In another embodiment, after transferring heat energy, the method in the above embodiment includes separating the crude oil portion into a purified oil portion and a separated water portion optionally including sediment and / or other impurities.

[0037] In an embodiment, the invention features a heating system for the heat treatment of a crude oil portion. The system includes a steam tube heat exchanger including a plurality of heat exchanger tubes, the steam tube heat exchanger being configured for installation within a heating vessel and being surrounded by the crude oil portion contained within the heating vessel. The system also includes an electric immersion vacuum steam heating system external to and fluidically coupled to the steam tube heat exchanger and configured for providing a steam portion to the plurality of heat exchanger tubes. The electric immersion vacuum steam heating system includes a steam boiler enclosing an electric immersion element and a first water portion, the electric immersion vacuum steam heating system being configured for generating, under vacuum or negative pressure, the steam portion having a steam temperature lower than the 212° F. when power is selectively supplied to the electric immersion element immersed in the first water portion contained within the steam boiler. The steam tube heat exchanger is configured for transferring heat energy released from condensation of the steam portion within the plurality of heat exchanger tubes to the crude oil portion contained within the heating vessel.

[0038] In still another embodiment, the invention features another heating system for the heat treatment of a crude oil portion. The system includes a shell and tube heat exchanger including a plurality of heat exchanger tubes enclosed within an internal volume of a shell, the shell and tube heat exchanger being configured for receiving the crude oil portion in the plurality of heat exchanger tubes and for receiving a steam portion in the internal volume of the shell. The system also includes an electric immersion vacuum steam heating system external to and fluidically coupled to the shell and tube heat exchanger and configured for providing the steam portion to the internal volume of the shell. The electric immersion vacuum steam heating system includes a steam boiler enclosing an electric immersion element and a first water portion, the electric immersion vacuum steam heating system being configured for generating, under vacuum or negative pressure, the steam portion having a steam temperature lower than the 212° F. when power is selectively supplied to the electric immersion element immersed in the first water portion contained within the steam boiler. The shell and tube heat exchanger is configured for transferring heat energy released from condensation of the steam portion to the crude oil portion via the plurality of heat exchanger tubes.BRIEF DESCRIPTION OF THE DRAWINGS

[0039] These and other features and advantages of the present invention will be better understood by reading the following detailed description, taken together with the drawings wherein:

[0040] FIG. 1 is a diagram of a front view of a vertically configured prior art firetube heating system for comparative purposes;

[0041] FIG. 2 is a drawing of a side partially cut-away view of a vertically configured prior art firetube heating system contrasted with side partially cut-away view of a vertically configured in-vessel heating system according to one embodiment of the present invention;

[0042] FIG. 3A is a drawing of a partially see-through isometric view of an in-vessel heating system fluidically coupled to an electric immersion vacuum steam heating system according to one embodiment of the present invention;

[0043] FIG. 3B is a diagram of a side view of the in-vessel heating system fluidically coupled to the electric immersion vacuum steam heating system of FIG. 3A according to this embodiment of the invention;

[0044] FIG. 4A is a diagram of a side view of heat exchanger tubes according to one embodiment of the present invention;

[0045] FIG. 4B is a diagram of an isometric view of the heat exchanger tubes of FIG. 4A according to this embodiment of the present invention;

[0046] FIG. 4C is a diagram of a side view of heat exchanger tubes according to another embodiment of the present invention;

[0047] FIG. 4D is a diagram of an isometric view of the heat exchanger tubes of FIG. 4C according to this embodiment of the present invention;

[0048] FIG. 4E is a diagram of a side view of heat exchanger tubes according to yet another embodiment of the present invention;

[0049] FIG. 4F is a diagram of an isometric view of the heat exchanger tubes of FIG. 4E according to this embodiment of the present invention;

[0050] FIG. 4G is a diagram of a side view of heat exchanger tubes according to a further embodiment of the present invention;

[0051] FIG. 4H is a diagram of an isometric view of the heat exchanger tubes of FIG. 4G according to this embodiment of the present invention;

[0052] FIG. 5A is an isometric view of an in-line heating system fluidically coupled to an electric immersion vacuum steam heating system according to one embodiment of the present invention;

[0053] FIG. 5B is a diagram of a side view of the in-line heating system fluidically coupled to the electric immersion vacuum steam heating system of FIG. 5A according to this embodiment of the present invention;

[0054] FIG. 6A is an isometric view of a heat exchanger according to one embodiment of the present invention;

[0055] FIG. 6B is a diagram of a side view of the heat exchanger tubes of the heat exchanger of FIG. 6A according to this embodiment of the present invention;

[0056] FIG. 6C is a diagram of a front view of the heat exchanger of FIGS. 6A and 6B according to this embodiment of the present invention;

[0057] FIG. 6D is an isometric view of a shell and tube heat exchanger according to one embodiment of the present invention;

[0058] FIG. 6E is a diagram of a top view of the heat exchanger tubes of the shell and tube heat exchanger of FIG. 6D according to this embodiment of the present invention;

[0059] FIG. 6F is a diagram of a side view of the heat exchanger tubes of the shell and tube heat exchanger of FIG. 6D according to this embodiment of the present invention;

[0060] FIG. 6G is a diagram of a side view of the shell and tube heat exchanger of FIG. 6D according to this embodiment of the present invention;

[0061] FIG. 6H is a diagram of a front view of the shell and tube heat exchanger of FIG. 6D according to this embodiment of the present invention;

[0062] FIG. 7A is a drawing of an isometric view of an electric immersion vacuum steam heating system according to one embodiment of the present invention;

[0063] FIG. 7B is a diagram of a side view of an electric immersion vacuum steam heating system including process and monitoring controls according to one embodiment of the present invention;

[0064] FIG. 8 is a diagram of a side view of in-line heating system coupled to an electric immersion vacuum steam heating system configured for operating under negative and subsequently positive pressure according to one embodiment of the present invention; and

[0065] FIG. 9 is a block diagram showing the steps of a method according to one embodiment of the present invention.DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0066] The present invention features safer, and more energy efficient and environmentally protective apparatus, system and method for heating crude oil prior to its transport and / or further processing. The invention features a crude oil heating system including one or more in-vessel and / or an in-line heating system(s) each including one or more heat exchanger(s). Each heat exchanger includes a plurality of or multiple tubes. The heat exchanger(s) are fluidically coupled to one or more external steam source(s) each including one or more electric immersion steam heating system(s). Each electric immersion vacuum steam heating system is configured for generating, under a vacuum or negative pressure, low temperature steam having a boiling point below 212° F., the boiling point temperature of water at atmospheric pressure.

[0067] The embodiments of the inventive crude oil heating apparatus, system and method are shown and discussed below for illustrative purposes in terms a single in-vessel heating system including a single vessel including a single heat exchanger or a single in-line heating system including a single shell and tube heat exchanger fluidically coupled to a separator vessel. Each of the in-vessel heat exchanger and the in-line shell and tube heat exchanger are fluidically coupled to a single external steam source including, but not limited to, a single electric immersion steam heating system, and where the crude oil heating system is controlled and monitored by a single controlling and monitoring system. In other embodiments, the system may include one or more of each of these components based on the heat load, other requirements for crude oil heat treatment, and the possibility for alternative or additional steam generation components and / or other system components.

[0068] For comparative purposes, FIG. 1 shows a diagram of a conventional prior art firetube heating system 10 including a generally u-shaped firetube 12 inserted in a heater treater vessel 14 and directly coupled to a gas supply 16. The heater treater vessel 14 is supplied with a starter water portion 20 sufficient to submerge the firetube 12. A crude oil portion 22 including an oil emulsion containing water and sediment and / or other impurities is supplied to the heater treater vessel 14 through a port 24 and the crude oil portion 22 is directed through the heater treater vessel 14 to for example a spreader 26 proximate to the firetube 12 where the crude oil portion 22 is comingled with the starter water portion 20 forming a crude oil-water mixture 28.

[0069] Upon firing, the burner 16 projects a flame via coupling 18 onto the interior surface of the walls of the firetube 12 and heat is transferred from the flame to and through the firetube walls to the surrounding crude oil-water mixture 28. The heating process aids or assists the crude oil water mixture to separate into a lighter purified oil portion 30 which settles on top of a heavier water-sediment-impurities portion 32 where the oil / water interface 33 is disposed above the firetube 12. The heavier water-sediment-impurities portion 32 is drained from the vessel via a port 34 or drain 35. The heated liquid oil portion exits the heating vessel 14 via the exit port 36. The free gas and light ends vaporized during the heating process rise in the heater treater vessel 14 and exit through the vaporized gas exit port 38.

[0070] FIG. 2 shows vertical configurations of the typical prior art firetube heating vessel 14 contrasted with an in-vessel heating system including a heating vessel 46 enclosing a heat exchanger 42 according to one embodiment of the invention. FIG. 2 shows the starter water portion 20 disposed below the firetube 12, a comingled oil and water mixture 28 surrounding the fire tube, an oil / water interface 33 disposed above the firetube 12, and a purified oil portion 30 disposed above the oil / water interface 33. In contrast, FIG. 2 shows a separated water portion 62 and an oil / water interface 59 disposed below the heat exchanger 42, the crude oil surrounding the heat exchanger 42, and purified oil portion 58 rising to the top of the vertically configured heating vessel 46.

[0071] FIGS. 3A and 3B show respectively a partially see through isometric view and a diagram of a side view of a crude oil heating system including an in-vessel heating system 40 according to one embodiment of the invention. The in-vessel heating system 40 includes a heat exchanger 42 including a plurality or bundle of heat exchanger tubes 44 disposed within a heating vessel 46. FIGS. 3A and 3B show the heating vessel 46 configured in a horizontal configuration, but the heating vessel 46 alternatively may be configured in a vertical configuration as shown in FIG. 2 or in another configuration. Piping or line 52 is configured for providing steam 50 from an external steam source 48 to the heat exchanger tubes 44 of the heat exchanger 42 disposed within the heating vessel 46. Condensate 51 from the heat exchanger 42 is recycled back to the external steam source 48 via piping or line 53. Crude oil 54 including an oil emulsion containing water and sediment and / or possibly other impurities is provided to the heating vessel 46 via piping or line 56. After heating, the heated crude oil separates into a purified oil portion 58 and a water-sediment-impurities portion 62. The purified oil portion 58 is withdrawn from heating vessel 46 via piping or line 60. The water-sediment-impurities portion 62 is withdrawn from the heating vessel via port or line 64. FIG. 3B shows that free gas and light ends vaporized during the heating process exit via port 65 and are collected.

[0072] The in-vessel heating system 40 is configured such that the steam 50 is provided to the tubes 44 of the heat exchanger 42 at a temperature in a range of 78° F. to 210° F. and preferably in a range of 150° F. to 200° F. The heat exchanger 42 is configured for operation on the tube side (inside the tubes) in a range of −29 inches mercury gauge to −1 inch mercury gauge, and preferably in a range of −22 inches mercury gauge to −6 inches mercury gauge; and on the vessel side in a range of 0 psig (14.7 psia) to 250 psig, and preferably in a range of 20 psig to 50 psig.

[0073] The in-vessel heating system 40 is configured such that when crude oil is provided to the vessel, the heat exchanger 42 is submerged in the crude oil, and the crude oil is heated to a range of between 100° F.-150° F., the heat exchanger tubes 44 will have an exterior surface temperature which is in a range of 0° F. to 10° F. above or greater than the temperature of the surrounding heated crude oil.

[0074] The exterior surface 66 of each heat exchanger tube 44 may have a corrosion protective and / or other surface coating 68 selected for having a working temperature which exceeds the maximum tube exterior surface temperature. The tube exterior surface coatings 68 are selected for having a working temperature greater than 250° F. The in-vessel heating system 40 prolongs the life of the tube exterior surface coatings 68 where the maximum tube surface temperature does not exceed the working temperature of the selected tube surface coatings 68.

[0075] The exterior surface 66 of each tube 44 has a coating 68 containing one or more material(s) which may be selected from a group of materials including a polymer material, an epoxy material, and a combination of polymer and epoxy material. Preferably, the coating 68 is configured for providing protection against corrosion. Each tube coating 68 has a thickness in a range of 8 mils to 25 mils and preferably in a range of 12 mils to 16 mils.

[0076] The heat exchanger 42 has a plurality of heat exchanger tubes 44 having a total heat transfer surface area which is configured based on the required heat duty of the specific application and the physical constraints of the system including the size of the heating vessel. The heat duty takes into consideration factors such as the volumetric capacity of the heating vessel, the incoming temperature and target volumetric flow rate or throughput of the crude oil for heating, the incoming temperature and amount of the low temperature steam available for heating, and the target exit temperature for the heated oil. The heat exchanger tube heat transfer area depends upon the number, length, and inside diameter of the heat exchanger tubes. Typically, the heat transfer surface area of the heat exchanger is in a range of 25 ft2 to 250 ft2 and preferably in a range of 75 ft2 to 200 ft2. The heat exchanger tubes 44 include one or more material(s) including carbon steel, stainless steel, and a combination of carbon and stainless steel. Each heat exchanger tube 44 has a tube thickness in a range of 0.1 inch to 0.5 inch and preferably in a range of 0.2 inch to 0.3 inch.

[0077] The in-vessel heating system 40 is configured such that at the typical operating pressure of the heat exchanger 42, upon filling the heating vessel with crude oil, each of the heat exchanger tubes 44 has a maximum heat exchanger tube exterior surface temperature which remains below the boiling temperature of water at the operating pressure of the heating vessel. The maintenance of the heat exchanger tube exterior surface temperatures below the boiling temperature of water at the operating pressure of the heating vessel 46 prevents water in the crude oil from boiling and ensuant mineral deposit build up or scaling on the exterior surfaces 66 of the heat exchanger tubes 44. The minimization of mineral deposit accumulation or scaling on the heat exchanger tube surfaces 66 increases the efficiency of heat transfer from the low temperature steam through the heat exchanger tubes 44 to the surrounding crude oil. The minimization of scaling build-up on the exterior of the heat exchanger also reduces production costs associated with lost production time for cleaning, repair and / or replacement of scaled components. When the crude oil is heated, the crude oil separates into a lighter purified oil portion and a heavier water-sediment-impurities portion. An oil / water interface 59 develops. The in-vessel heating oil system 40 is configured that the oil / water interface 59 is below the heat exchanger and thus heat transfer to the surrounding crude oil is maximized. The water level and the oil / water interface 59 are controlled by the vessel control system which removes water as the water rises to a preset maximum height, preferably below the tube heat exchanger. Thus, absorption of heat by the liquid water condensate phase in the heat exchanger tubes 44 is minimized.

[0078] Depending upon a vertical or a horizontal configuration of the heating vessel, an in-vessel system heat exchanger occupies between 33% to 66% less volume than a firetube, where the in-vessel heating vessel and the firetube heater treater vessel have the same size. Thus, more volume is available for the crude oil in the in-vessel heating vessel as compared to the firetube heater treater vessel.

[0079] In contrast with the typical firetube including a u-shaped tube having a first hot end where the flame is projected and a second cold end where combustion gases exit, the entire surface of each heat exchanger tube 44 is available for heat transfer. The heat exchanger 42 provides a uniform heat profile including a uniform amount of heat transfer from the low temperature steam along the entire surface of the heat exchanger 42 as a function of the steam's latent heat of vaporization.

[0080] The number, length, number of layers, and arrangement or configuration of the heat exchanger tubes 44 are be selected based on the heat transfer coefficients, the size of the heating vessel 46, the volume of oil being heated, and the required heat duty, for maximizing heat transfer efficiencies. For a non-limiting example, the utilization of multiple small tubes promotes natural or free convection through the spaces between exchanger tubes instead of around the traditional firetube. This natural or free convection aids in increasing overall efficiency.

[0081] In non-limiting embodiments, the heat exchanger tubes 44 may be of variable lengths, as shown in FIGS. 4A and 4B, may be of equal lengths, as shown in FIGS. 4C and 4D, may be arranged in vertical configurations, as shown in FIGS. 4E-4H, horizonal configurations as shown in FIGS. 4A-4D, or in other configurations, and may be arranged in single (not shown) or multiple layers. In non-limiting embodiments not shown, the surface 66 of the heat exchanger tubes 44 may be corrugated or otherwise contoured also for maximizing heat transfer efficiencies. In other non-limiting embodiments not shown, the heat exchanger tubes 44 may be multiple pass tubes.

[0082] In another embodiment of the invention, FIGS. 5A and 5B show respectively an isometric view and a diagram including a side view of the crude oil heating system of the invention including an in-line heating system 70 including a shell and tube heat exchanger 71. The shell and tube heat exchanger 71 includes one or more tubes 72 disposed in a shell internal volume 73 enclosed by a shell 74. Steam 76 from an external steam source 78 is supplied via line or piping 80 to the shell internal volume 73 enclosed within the shell 74. Crude or oil for heating treatment 90 is supplied to the tubes 72 through piping or line 92. The heating system is configured such that when steam 76 condenses, the latent heat released through condensation of the steam is transferred to the crude oil 90 disposed in the tubes 72 thereby heating the crude oil 90. The condensation of the steam 76 produces a liquid water condensate 86 which is recycled via line or piping 88 back to the external steam source 78. The heated oil 94 exits the tubes 72 through exit port 96. In the event of a steam boiler over pressure / over temperature scenario, steam 82 is released via a pressure release valve and via line 84.

[0083] The in-line heating system 70 is configured such that the steam 76 is provided to the shell internal volume 73 at a temperature in a range of 78° F. to 210° F. and preferably in a range of 150° F. to 200° F. The shell and tube heat exchanger 71 is configured for operation on the tube side (inside the tubes 72) in a range of 0 psig (14.7 psia) to 250 psig, and preferably in a range of 20 psig to 50 psig; and on the shell side in a range of −29 inches mercury gauge and −1 inch mercury gauge, and preferably in a range of −22 inches mercury gauge to −6 inches mercury gauge.

[0084] The in-line heating system 70 is configured such that the crude oil crude oil is heated to a range of between 100° F.-150° F. When the crude oil is thus heated, the surface of the tubes 72 will have a temperature which is in a range of 0° F. to 10° F. above or greater than the temperature of the heated crude oil contained within.

[0085] The in-line heating system is configured such that heated oil 94 exiting the tubes 72 via line 96 is delivered to either a subsequent separator or other processing, treatment or holding vessel. In a non-limiting embodiment, FIG. 5B shows heated oil 94 is delivered to a separator vessel 130 where the heated crude oil 94 separates into a purified oil portion 132 and a water-sediment-impurities portion 134. The purified oil portion 132 then exits the separator vessel 130 via line 136 and the water-sediment-impurities portion exits the separator vessel 130 via line 138. The free gas and light ends vaporized during the heating process exit via port 135 and are collected.

[0086] The in-line heating system 70 provides an additional layer of safety where all heat sources are removed from the vessel 130 where separation of heated crude oil into a purified oil portion and a water-sediment-impurities portion occurs. Such a separator vessel 130 optionally may have a smaller volume as compared to the heating vessel 46 of the in-vessel heating system 40 which is sized for enclosure of the heat exchanger 42. Alternatively, the subsequent separator, processing, treatment or holding vessel may be sized similar to a traditional heater treater vessel thereby providing the option for longer retention time and increased system capacity.

[0087] The in-line heating system 70 including a shell and tube heat exchanger 71 may be particularly useful in applications involving vessel size constraints, where, for example, a heating or other specialized treatment vessel is not sufficiently large to accommodate the required heat transfer area of an in-vessel tube heat exchanger. Although the overall footprint of the in-line heating system may be larger than the in-vessel heating system where heating and oil / water separation take place in the same vessel, the shell and tube heat exchanger 71 may provide economic benefits in situations where the subsequent specialized treatment vessel may be replaced with a relatively more simplified and less costly holding vessel.

[0088] FIGS. 6A-6C show further exemplary configurations of the in-vessel tube heat exchanger. FIG. 6A shows a heat exchanger 100 including a plurality of or multiple heat exchanger tubes 102. The heat exchanger 100 has a steam supply nozzle 104 configured for receiving steam from the external steam source. The received steam passes to each of the heat exchanger tubes 102 via the steam throat 106. Condensate exits the heat exchanger through the condensate return nozzle 108 and is recycled back to the external steam source. FIG. 6B shows a side view of a single stack of heat exchanger tubes 102 and steam throat 106 of the in-vessel heat exchanger of FIG. 6A. The height H of the stack of heat exchanger tubes 102 corresponds to the total number of heat exchanger tubes in the stack. The height H of the heat exchanger tube stack and the length L of the heat exchanger tubes 110 are selected based on the heat load requirements of the system. FIG. 6C shows a front view of the in-vessel heat exchanger 100 and FIG. 6A including the steam receiving nozzle 104 and the condensate nozzle 108. Each of FIG. 6A and FIG. 6C identify exemplary first and second flanges or lifting lugs 109′, 109″ configured for the attachment or other installation of the heat exchanger 102 to the surrounding heating vessel as necessary.

[0089] FIG. 6D shows a view of a shell and tube heat exchanger 110 characteristic of an in-line heating system including a vacuum steam chamber 112, a steam supply nozzle 114, a condensate return nozzle 118, a crude oil inlet 116, and a process nozzle 119 for passing the heated oil to a subsequent separator, processing, treatment, separator, or holding vessel, or other downstream component.

[0090] FIG. 6E shows a side view and FIG. 6F a top view of the heat exchanger tubes 120 disposed in the shell and tube heat exchanger shown in FIG. 6D while FIG. 6G shows a diagram of an exterior side view of the shell and tube heat exchanger 110 of FIG. 6D including the vacuum steam chamber 112 and the steam supply nozzle 114. FIG. 6H includes a front view of the shell and tube heat exchanger 110 of FIG. 6D including process nozzle 116 configured for receiving crude oil for treatment and process nozzle 119 configured for passing the heated oil to subsequent treatment.

[0091] The external steam source corresponding to element 48 in FIGS. 3A and 3B or element 78 in FIGS. 5A and 5B includes an electric immersion vacuum steam heating system. The electric immersion vacuum steam heating system includes an electric immersion element configured for immersion in a water solution under a vacuum where the powered electric immersion element heats directly the surrounding water solution to form steam. The use of an electric immersion element contacted directly with the surrounding water solution ensures that all of the heat energy produced by passing electricity through a resistance element of the electric immersion element is absorbed by or transferred to the water solution surrounding the electric immersion element. The electric immersion vacuum heating system prevents or limits mineral deposit buildup or scaling on the electric immersion element and other water exposed elements of the system by including a water solution including demineralized water and by its configuration as a closed or sealed system where no additional water including possibly less pure water is added to the system.

[0092] The electric immersion vacuum steam heating system also operates with minimal system heat losses, where the system is configured for operation under vacuum and does not suffer combustion related heat losses. The electric immersion vacuum steam heating system is configured for operation with a heat transfer efficiency in a range of 80% to 98%, and preferably in a range of 92% to 95%, and most preferably at a heat transfer efficiency of 98%. The heat transfer efficiency electric immersion vacuum heating system is less than 100% because some ambient heat loss occurs through the walls or surface of the steam boiler of the electric immersion vacuum heating system. The walls or surface are insulated for minimization of such heat losses.

[0093] The electric immersion vacuum steam heating system is configured for operation under vacuum or negative pressure for production of steam at a temperature lower than the 212° F. boiling point temperature of water at atmospheric pressure. The temperature of the steam may be regulated by controlling the pressure of the system. The electric immersion vacuum heating system is configured for operation in an initial vacuum or negative pressure range upon sealing the system of −27 inches mercury gauge to −29 inches mercury gauge. Under the operating vacuum or negative pressure, the system is configured for the generation of steam at a steam temperature in a range of 78° F. to 210° F. and preferably in a range of 150° F. to 200° F. In a preferred embodiment, the electric immersion vacuum heating system forms part of a vacuum boiler meeting the requirements of one or more of ASME boiler design requirements.

[0094] The electric immersion vacuum heating system does not require the energy of a typical circulation type process because when the liquid water component changes phase from liquid water to vapor, the liquid water component expands by approximately 1600 times and fills every void in the system automatically eliminating the need for an external motive force. In a typical hot water circulation system, one pound of liquid water must give up one degree Fahrenheit to release 1 British thermal unit or btu of heat. In contrast, the condensation of one pound of steam into one pound of liquid water at the same temperature releases approximately 970 btu of heat. Makeup water is not required because the system is sealed or closed, the generated steam is delivered to the heat exchanger, and condensate therefrom is recirculated back to the electric immersion vacuum steam heating system.

[0095] Lack of additional makeup water eliminates or reduces the need or requirements for water quality monitoring and / or related chemical treatment. The vacuum system enables a quick response to heat load. Steam at a minimum temperature of 78° F. is available for the heating of crude oil. The electric immersion vacuum steam heating system does not require the system to heat up to or maintain a particular temperature in order to be ready or responsive to a heat load request thus saving energy and increasing efficiency. Electric immersion elements are considered as a SCOPE 1 zero-emission heat source. The operation of the system under vacuum is inherently safer than a positive pressure system.

[0096] The crude oil heating systems featured in FIGS. 3A and 5A include a respective electric immersion vacuum steam heating 48 and 78 system including a controlling and monitoring system 190 configured for controlling the power to the electric immersion element in response to the requested heat load, and for monitoring the corresponding in-vessel or in-line heating system. FIG. 7A shows a perspective or isometric view and FIG. 5B a process and instrumentation diagram of a side view of an electric immersion vacuum steam heating system 150 in according to one non-limiting embodiment. The electrical immersion vacuum heating system 150 includes a steam boiler 152, such as, for a non-limiting embodiment, a boiler vessel constructed according to appropriate ASME standards, and one or more electric immersion elements 154. Steam generated by the system exits through the steam port or line 156. Condensate recycled back from the heat exchanger is received in the gravity condensate return 158 and reintroduced back into the steam boiler 152 through the integrated Hartford loop 160. The electric immersion vacuum steam heating system 150 may also include one or more of a rupture disc 162, a temperature limit controller 164, a high temperature limit controller 166, a pressure limit controller or switch 168, a low fluid level switch 170, a pressure gauge 172, a temperature gauge 174, a site glass 176, a sample port or line 178, a drain port or line 180, and a vacuum port or line 182.

[0097] The control and monitoring system is configured such that a controller 192 selects the power transmitted from a power source 194 to the electric immersion element 154 based upon a temperature of the oil and / or the steam in the oil heating vessel which is communicated or transmitted to the controller as shown schematically by line 196 in FIG. 7B and / or based upon a steam temperature or negative pressure operating condition of the steam boiler 152. The control and monitoring system 190 is configured such that the controller 192 is in electronic communication with the temperature limit controller 164, the high temperature limit controller 166, the pressure limit controller 168 and the low fluid level switch 170. Element 197 corresponds to an optional control input for setting a remote crude oil temperature setpoint. Element 198 corresponds to an optional dry contact input for remotely starting or stopping the heating system The temperature limit controller 164 limits the boiler steam temperature to a nominal setting. When the boiler steam temperature reaches the nominal setting, the controller 164 stops or shuts off the power flow to the system. When the boiler steam temperature drops below the nominal setting, the power flow is resumed.

[0098] The high temperature limit controller 166 is a fail-safe high limit controller. In the event the controller 164 malfunctions, and the boiler steam temperatures reaches a temperature the high limit controller nominal setting which is typically 5° F.-10° F. higher than the nominal setting of the temperature limit controller 164, the high limit temperature controller 166 stops or shuts off the power flow to the system and effectively locks out the system. A manual intervention is then required to re-start the system.

[0099] The coupling of the electric immersion vacuum steam heating system to the heat exchangers of the in-vessel or in=line heating systems as featured in the invention thus provide many improvements over the conventional first firetube heating systems. The flame heat source is replaced with the low temperature heat exchanger. If a tube failure occurs, there is no direct path for the crude oil to reach an ignition source and as such, provides an inherently safer system. The sealed or closed electric immersion vacuum steam heating system coupled with the oil heating vessel and the use of demineralized water or water solution protects the water exposed elements of the electric immersion vacuum steam from corrosion. The electric immersion vacuum steam heating system acts as a passive differential pump. When the steam touches the cold surface of the heat exchangers, the steam condenses and contracts by the same 1600 times. The contraction creates a small pressure differential drawing new steam into the heat exchanger and allowing condensate to drain out of the heat exchanger by the force of gravity.

[0100] In a preferred embodiment, the heat exchanger is configured such that the condensate drains back to the electric immersion vacuum steam heating system including the electric immersion element heat source by gravity without the need for pumps or other fluid drivers. The condensate remixes with the water solution in the electric immersion vacuum steam heating system after which it is again heated and formed into steam. The process becomes a self-sustaining circulation loop which may continue even after the heat source is removed until the steam temperature drops to equal the crude oil temperature.

[0101] The crude oil is typically heated to a range of 100° F.-150° F. satisfying crude oil treatment regulatory requirements through the use of steam having a temperature in a range of 78° F. to 210° F., and preferably in a range of 150° F. to 200° F. produced under a vacuum thereby eliminating or reducing the hazards associated with the traditional crude oil heating systems.

[0102] The use of low temperature steam with tubular heat exchangers in lieu of the traditional firetubes reduces maintenance and lost production costs associated with changing firetubes and extends the operating life of the overall system. The use of SCOPE 1 zero emission electric heat reduces greenhouse emissions at the point of oil production and avoids the overall system maintenance costs associated with maintaining the necessary fuel quality for operating gas fired combustion associated with the standard firetube system.

[0103] In another embodiment, FIG. 8 shows a heating system 200 including an electric immersion vacuum steam heating system 201 including a steam boiler 202, where the steam boiler 202 is configured for generation of steam under vacuum and subsequently under positive pressure. The steam boiler 202 is configured for generating under vacuum or negative pressure steam having a first temperature and for subsequently allowing the steam to build pressure thereby raising the temperature of the steam to a second temperature higher than the first temperature. The steam having the second steam temperature may be used to increase heat transfer as necessary in particular applications. The shell and tube heat exchanger 204 includes one or more tubes 206 disposed within a shell internal volume 207 enclosed by a shell 208. The shell and tube heat exchanger 204 is fluidically coupled via line 210 to a subsequent processing tank 212. Although FIG. 8 shows the steam boiler 202 as fluidically coupled with a shell and tube heat exchanger 204 characteristic of an in-line heating system, in other non-limiting embodiments not shown, the steam boiler 202 may be coupled to a heat exchanger characteristic of an in-vessel heating system.

[0104] The steam boiler 202 includes an electric immersion element or elements 214 for generating under vacuum a steam portion 216 from liquid water, where the first steam portion has a first steam temperature in a range of 78° F. to 210° F., and preferably in a range of 150° F. to 200° F. The electric immersion vacuum heating system is configured for operation in an initial or first vacuum or negative pressure upon sealing the system in a range of −27 inches mercury gauge to −29 inches mercury gauge.

[0105] The system 200 is configured such that the steam 216 from the external steam boiler 202 is supplied via line or piping 217 to the shell internal volume 207 of the shell and tube heat exchanger 204. Crude oil or oil for heating treatment 218 is supplied to the tubes 206 of the shell and tube heat exchanger 204 through piping or line 219. The heating system is configured such that when steam 216 condenses, the latent heat released through condensation of the steam is transferred to the crude oil 218 disposed in the tubes 206 thereby heating the crude oil 218. The condensation of the steam 216 produces a liquid water condensate 220 which is recycled via line or piping 222 back to the external steam source 202. The heated oil 210 exits the tubes 206 via line 211. In the event of a steam boiler over pressure / over temperature scenario, steam is released via a pressure release valve and piping not shown.

[0106] The first steam portion is provided to the shell and tube heat exchanger 204 at a first steam temperature in a range of 78° F. to 210° F. and preferably in range of 150° F. to 200° F. The shell and tube heat exchanger 204 is configured for operation on the shell side at a first shell side pressure in a range of −29 inches mercury gauge to −1 inch mercury gauge, and preferably in a range of −22 inches mercury gauge to −6 inches mercury gauge and on the tube side (inside the tubes 206) at a pressure in a range of 0 psig (14.7 psia).

[0107] The system 200 is configured such that the crude oil crude oil is heated to a first crude oil temperature in a range of between 100° F.-150° F. When the crude oil is thus heated, the surface of the tubes 206 will have a temperature which is in a range of 0° F. to 10° F. above or greater than the temperature of the heated crude oil contained within the tubes 206. Heat transfer from the steam portion 216 at the first steam temperature to the oil crude portion 218 will occur at a first heat transfer rate based on the process conditions including the first temperature differential between the first steam temperature and the crude oil temperature.

[0108] When the rate of steam production in the electric immersion vacuum steam heating system 200 exceeds the rate of water condensation 220 exiting the heat exchanger via line 222, the system 200 is configured to enable pressure to build in the steam boiler 202 to a second boiler pressure in range of 0 psig and 150 psig, and preferably to a range of 25 psig to 140 psig. At the second boiler pressure, the pressurized steam in the boiler has a second steam temperature in a range of 212° F. to 366° F., and preferably in a range of 266° F. to 360° F.

[0109] The system 200 is configured such that the second steam portion including pressurized steam at the second steam temperature is then provided to the shell internal volume 207. When the second steam portion including the pressurized steam is provided, the shell and tube heat exchanger 204 is configured for operation on the shell side at a second shell side pressure in a range of 0 psig to 150 psig, and preferably in a range of 25 psig to 140 psig. The shell and tube heat exchanger is configured such that the pressure on the tube side (within the tubes) remains between 0 to 250 psig, and preferably between 20 psig to 50 psig, and the oil is heated to a range of 100° F. to 150° F. where the surface of the tubes is between 0° F. to 10° F. higher the temperature of the crude oil contained within the heat exchanger tubes. The second heat transfer rate is higher than the first heat transfer rate where the temperature differential between second steam temperature and the crude oil temperature is higher than the temperature differential between the first steam temperature and the crude oil temperature. A smaller shell and tube heat exchanger then may be used for the crude oil heat treatment where such a second higher heat transfer rate is available.

[0110] The system 200 is configured to allow the pressure to build in the steam boiler 202 until the steam boiler pressure reaches a nominal pressurized system set point. If the steam boiler pressure builds to the point of reaching a nominal pressurized system set point, the pressurized system controller 224 will shut off power flow from the power supply 226 to the electric immersion element 214 and the heating system will be temporarily shut down. When the steam boiler pressure falls back below the nominal pressurized system set point, the pressurized system controller 224 will resume power flow from the power supply 226 the electric immersion element for further steam generation. Thus, the electric immersion vacuum steam heating system 200 is configured for control based on pressure in the steam boiler 202 as well as by the temperature of the steam or the oil.

[0111] The heated crude oil 210 is then supplied via line 211 to a subsequent separator or other processing vessel 212 where the heated crude oil separates into a purified oil portion 230 and a water-sediment-impurities portion 234. The purified oil portion exits the vessel via line 232. The water-sediment-impurities portion 234 exits the processing vessel 212 via line 236.

[0112] In another embodiment, the invention features a method 250 for heating a portion of crude oil as shown in FIG. 9. The method 250 includes providing a heat exchanger having a plurality of heat exchanger tubes in step 252; and providing an electric immersion vacuum steam heating system external to and fluidically coupled to the heat exchanger, the electric immersion vacuum steam heating system including a steam boiler configured for enclosing an electric immersion element and a first water portion in step 254; generating, under vacuum or negative pressure, a steam portion having a steam temperature lower than the 212° F. when power is selectively supplied to the electric immersion element immersed in the first water portion contained within the steam boiler in step 256; providing the steam portion to the heat exchanger in step 258; and transferring heat energy from the steam portion to the crude oil portion via the plurality of heat exchanger tubes in step 260. In a further embodiment, the method 250 includes the additional step 262 including after transferring heat energy, separating the crude oil portion into a purified oil portion and a separated water portion optionally including sediment and / or other impurities.

[0113] Accordingly, the present invention provides a heating system, apparatus and method for the heat treatment of crude oil including a tubular heat exchanger and an electric immersion vacuum steam heating system external to and fluidically coupled to the tubular heat exchanger for providing steam portion to the heat exchanger to safely and efficiently heat the oil being processed.

[0114] The present invention is discussed in the context of the heat treatment of crude oil but may be applied to the heat treatment of other fluids as necessary. The present invention is not intended to be limited to a device or method which must satisfy one or more of any stated or implied objects or features of the invention and should not be limited to the preferred, exemplary, or primary embodiment(s) described herein.

[0115] Modifications and substitutions by one of ordinary skill in the art are considered to be within the scope of the present invention, which is not to be limited except by the allowed claims and their legal equivalents.

Claims

1. A heating system for the heat treatment of a crude oil portion comprising:a heat exchanger including a plurality of heat exchanger tubes; andan electric immersion vacuum steam heating system external to and fluidically coupled to the heat exchanger and configured for providing a steam portion to the heat exchanger;wherein the electric immersion vacuum steam heating system includes a steam boiler enclosing an electric immersion element and a first water portion, the electric immersion vacuum steam heating system being configured for generating, under vacuum or negative pressure, the steam portion having a steam temperature lower than the 212° F. when power is selectively supplied to the electric immersion element immersed in the first water portion contained within the steam boiler; andwherein the heat exchanger is configured for transferring heat energy released from condensation of the steam portion to the crude oil portion via the plurality of heat exchanger tubes.

2. The heating system of claim 1, wherein the crude oil heating system is configured such that the steam portion provided to the heat exchanger has a steam temperature in a range of 78° F. to 210° F.

3. The heating system of claim 1, wherein the heating system is configured enabling the crude oil portion to reach a heated oil temperature in a range of 100° F. to 150° F. after heat energy released from condensation of the steam portion is transferred to the crude oil portion via the plurality of heat exchanger tubes.

4. The heating system of claim 1, wherein the electric immersion vacuum steam heating system is configured for drawing a vacuum in a negative pressure range of −27 inches mercury gauge to −29 inches mercury gauge prior to sealing of the electric immersion steam heating system.

5. The heating system of claim 1, wherein the electric immersion vacuum steam heating system is a closed system where no additional water is added to the electric immersion vacuum steam heating system after the first water portion is supplied.

6. The heating system of claim 1, wherein the first water portion includes demineralized water.

7. The heating system of claim 1, wherein a heat transfer efficiency of the electric immersion vacuum steam heating system is in a range of 80% to 98%.

8. The heating system of claim 1, wherein the steam boiler includes a vacuum boiler constructed in accordance with corresponding then current ASME standards.

9. The heating system of claim 1, wherein the heat exchanger is configured for receiving the steam portion inside the plurality of heat exchanger tubes and for the heat exchanger tubes being surrounded by the crude oil portion.

10. The heating system of claim 9, wherein the heat exchanger is disposed in a heating vessel being configured for separation of the crude oil portion into a purified oil portion and a separated water portion optionally including sediment and / or other impurities after heat energy released from condensation of the steam portion is transferred to the crude oil portion.

11. The heating system of claim 10, wherein the heating system is configured such that a surface temperature of an exterior surface of each of the plurality of heat exchanger tubes is below a boiling temperature of water at an operating pressure of the heating vessel.

12. The heating system of claim 10,wherein each of the plurality of heat exchanger tubes has an exterior surface having at least a partial coating protective against corrosion, said partial coating having a coating working temperature; andwherein the heating system is configured such that an exterior surface temperature of each of the plurality of heat exchanger tubes at an operating pressure of the heating vessel is below the coating working temperature.

13. The heating system of claim 1,wherein the heat exchanger is configured for receiving the crude oil portion inside the plurality of heat exchanger tubes;wherein the heat exchanger includes a shell having a shell internal volume enclosing the plurality of heat exchanger tubes; andwherein the heat exchanger is configured for receiving the steam portion inside the shell internal volume surrounding the plurality of heat exchanger tubes.

14. The heating system of claim 13, wherein after heat energy released from condensation of the steam portion is transferred to the crude oil portion, the heating system is configured for delivery of the crude oil portion from the plurality of heat exchanger tubes to a separator vessel configured for separation of the crude oil portion into a purified oil portion and a separated water portion optionally including sediment and / or impurities.

15. The heating system of claim 13, wherein the heating system is configured such that a surface temperature of an interior surface of each of the plurality of heat exchanger tubes is below a boiling temperature of water at an operating pressure within the plurality of heat exchanger tubes.

16. A heating system according to claim 13,wherein the steam portion having the steam temperature comprises a first steam portion having a first steam temperature lower than 212° F.;wherein the electric immersion vacuum steam heating system is configured for generating, a second steam portion having a second steam temperature higher than the first steam temperature under positive pressure;wherein after heat energy released from condensation of the first steam portion is transferred to the crude oil portion, the electric immersion vacuum steam heating system is configured for providing the second steam portion to the shell internal volume and transferring heat energy released from condensation of the second steam portion to the crude oil portion via the plurality of heat exchanger tubes.

17. A method for heating a crude oil portion comprising:providing a heat exchanger having a plurality of heat exchanger tubes; andproviding an electric immersion vacuum steam heating system external to and fluidically coupled to the heat exchanger, the electric immersion vacuum steam heating system including a steam boiler configured for enclosing an electric immersion element and a first water portion;generating, under vacuum or negative pressure, a steam portion having a steam temperature lower than the 212° F. when power is selectively supplied to the electric immersion element immersed in the first water portion contained within the steam boiler;providing the steam portion to the heat exchanger; andtransferring heat energy released from condensation of the steam portion to the crude oil portion via the plurality of heat exchanger tubes.

18. The method of claim 17, further comprising:after transferring heat energy, separating the crude oil portion into a purified oil portion and a separated water portion optionally including sediment and / or other impurities.

19. A heating system for the heat treatment of a crude oil portion comprising:a steam tube heat exchanger including a plurality of heat exchanger tubes, the steam tube heat exchanger being configured for installation within a heating vessel and being surrounded by the crude oil portion contained within the heating vessel; andan electric immersion vacuum steam heating system external to and fluidically coupled to the steam tube heat exchanger and configured for providing a steam portion to the plurality of heat exchanger tubes;wherein the electric immersion vacuum steam heating system includes a steam boiler enclosing an electric immersion element and a first water portion, the electric immersion vacuum steam heating system being configured for generating, under vacuum or negative pressure, the steam portion having a steam temperature lower than the 212° F. when power is selectively supplied to the electric immersion element immersed in the first water portion contained within the steam boiler; andwherein the steam tube heat exchanger is configured for transferring heat energy released from condensation of the steam portion within the plurality of heat exchanger tubes to the crude oil portion contained within the heating vessel.

20. A heating system for the heat treatment of a crude oil portion comprising:a shell and tube heat exchanger including a plurality of heat exchanger tubes enclosed within an internal volume of a shell, the shell and tube heat exchanger being configured for receiving the crude oil portion in the plurality of heat exchanger tubes and for receiving a steam portion in the internal volume of the shell; andan electric immersion vacuum steam heating system external to and fluidically coupled to the shell and tube heat exchanger and configured for providing the steam portion to the internal volume of the shell;wherein the electric immersion vacuum steam heating system includes a steam boiler enclosing an electric immersion element and a first water portion, the electric immersion vacuum steam heating system being configured for generating, under vacuum or negative pressure, the steam portion having a steam temperature lower than the 212° F. when power is selectively supplied to the electric immersion element immersed in the first water portion contained within the steam boiler; andwherein the shell and tube heat exchanger is configured for transferring heat energy released from condensation of the steam portion to the crude oil portion via the plurality of heat exchanger tubes.

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