TECHNICAL FIELD
The present disclosure relates to the refining of crude oil. Specifically, the present disclosure is directed towards an improved desalting vessel for refining of crude oil. More specifically, the present disclosure is directed towards the construction and mechanism of an inlet distributor in the desalting vessel for separation of crude oil and water.
BACKGROUND OF THE PRESENT DISCLOSURE
The information in this section merely provides background information related to the present disclosure and may not constitute prior art(s).
Generally, crude oil, when extracted from an oil reservoir, contains water, salts and suspended solids, collectively termed as impurities. These undesired impurities may vary in quantity and quality depending upon the oil reservoir. Further, water is mixed thoroughly with crude oil before introducing the same in the desalting vessel to improve the separation of impurities from the crude oil.
Water may be present in large quantities in crude oil extracted from older reservoirs or if crude oil extraction is enhanced using water injection technology. Also, the impurities in crude oil can adversely affect downstream refining processes by causing fouling, increasing corrosion rates, poisoning catalysts and increasing environmental concerns. The salts that are most frequently present in crude oil are sodium chlorides, calcium chlorides and magnesium chlorides. The salts, at high temperatures in the downstream processing, could form hydrochloric acids, which can corrode the downstream equipment such as heat exchangers. Suspended solid particles and salts may get deposited in heat exchangers causing fouling and reducing the pre-heat capacities of the Heat Exchangers. Sodium, Arsenics and other metals may cause poisoning of catalysts. These solid particles may get carried to the burners and eventually flue gas, where they would cause problems with environmental compliance of refineries.
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With on-going efforts to provide, a number of arrangements have been proposed for separation of impurities in crude oil. One such separation device is a desalting vessel for separating crude oil (referred to as crude hereinafter) and impurities. Generally, a desalting vessel comprises mainly of the four internals: an inlet distributor, an outlet collector, an effluent collector and a set of electric grids. The desalting vessel provides distribution of crude-water mixture uniformly along the length of the vessel with uniform velocity. The said crude-water mixture is then distributed in the interface zone (the injection velocity of the mixture from the individual holes in the inlet distributor (also called as, hole velocity) should be less than 1 m/s). The laminar flow pattern of the crude-water mixture inside the vessel enhances the gravity separation of the crude-water mixture.
However, there is one major drawback associated with such desalting vessels. As the refiners increase the flow rates of the crude to meet their product demand, the hole velocity is bound to increase. This creates a turbulent zone near the inlet distributor, which affects the gravity separation of the crude and water. Thus, decreasing the efficiency of the desalting vessel.
In light of the foregoing discussion, there is a need to provide an improved desalting vessel for separation of crude and water to overcome one or more limitations stated above.
SUMMARY
One or more drawbacks of conventional desalting vessels as described in the prior art are overcome and additional advantages are provided through the desalting vessel for crude-water mixture as claimed in the present disclosure. Additional features and advantages are realized through the technicalities of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered to be a part of the claimed disclosure.
In one non-limiting embodiment of the present disclosure, there is provided a desalting vessel for crude-water mixture comprising an inlet header, a crude outlet, an effluent outlet collector, a plurality of electric grids disposed in the vessel. A plurality of horizontal inlet distributor headers for distributing the crude-water mixture
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horizontally along the length of the vessel. Each of the distributor header comprises pipes with a plurality of holes and centrifugal channels, co-axial with the pipes. Each of the distributor pipe is encapsulated by an envelope for receiving the mixture from the inlet pipe. The distributor pipe is encapsulated by a centrifuge channel, coaxial with the distributor pipe, for receiving the mixture from the pipe. A centrifugal channel comprising an inlet for receiving the mixture from the holes of the distributor pipe and an outlet for ejecting the mixture through the flow channel is configured to impart a centrifugal motion to the mixture as it passes through the channel.
In an embodiment of the present disclosure, the vessel comprises a vertical inlet pipe for distribution of crude-water mixture which extends from a bottom center of the vessel to a height equal to/above the liquid interface of the vessel.
In another embodiment of the present disclosure, the vessel comprises a plurality of horizontal pipes, for distribution of crude-water mixture from the vertical inlet pipes, which divert flows towards the dish ends of the vessel.
In a further embodiment of the present disclosure, the horizontal pipes comprise a plurality of holes distributing the crude-water mixture on to the diverting plates.
In one more embodiment of the disclosure, the diverting plates receiving crude-water mixture deviates the mixture into the envelop smoothly.
In a still further embodiment of the present disclosure, the envelopes provide centrifugal effect to the crude-water mixture before ejecting the mixture into the desalter vessel.
In another embodiment, the ratio of the inside diameters of inlet distributor pipes and its envelop shall be in the range of 1.5-2.0.
The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described
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above, further aspects, embodiments, and features will become apparent with reference to the drawings and the following detailed description.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The novel features and characteristics of the disclosure are set forth in the appended description. The disclosure itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying figures. One or more embodiments are now described, by way of example only, with reference to the accompanying figures wherein like reference numerals represent like elements and in which:
Figure 1 shows a perspective view of the present desalter vessel according to an embodiment of the present disclosure.
Figure 2 depicts an isometric view of the present desalter vessel, according to an embodiment of the present disclosure.
Figure 3 depicts an isometric view of the present desalter vessel, according to an embodiment of the present disclosure.
Figure 4 shows a sectional view of the centrifugal channel of the present desalter vessel, according to an embodiment of the present disclosure.
The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the assemblies and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION
While the invention is subject to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the figures and will be
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described below. It should be understood, however that it is not intended to limit the invention to the particular forms disclosed, but on the contrary, the invention is to cover all modifications, equivalents, and alternative falling within the spirit and scope of the invention as defined by the appended claims.
Before describing in detail the various embodiments of the present disclosure it may be observed that the novelty and inventive step that are in accordance with a desalting vessel for crude-water mixture. It is to be noted that a person skilled in the art can be motivated from the present disclosure and can perform various modifications. However, such modifications should be construed within the scope of the invention.
Accordingly, the drawings are showing only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having benefit of the description herein.
The terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non-exclusive inclusion, such that an assembly, setup, system, device that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such system or device or setup. In other words, one or more elements in the system or apparatus or device proceeded by “comprises a” does not, without more constraints, preclude the existence of other elements or additional elements in the assembly or system or apparatus. The following paragraphs explain present disclosure. The invention in respect of the same may be deduced accordingly.
Accordingly, it is an aim of the present disclosure to provide an improved desalter vessel for the separation of water from a crude-water mixture.
One more aim of the present disclosure is to provide a desalter vessel which provides centrifugal separation prior to gravity separation.
Accordingly, the present disclosure provides a desalting vessel for crude-water mixture comprising an inlet header, a crude outlet, an effluent outlet collector, a
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plurality of electric grids disposed in the vessel. A plurality of horizontal inlet distributor headers for distributing the crude-water mixture horizontally along the length of the vessel. Each of the distributor header comprises pipes with a plurality of holes and centrifugal channels, co-axial with the pipes. Each of the distributor pipe is encapsulated by an envelope for receiving the mixture from the inlet pipe. Each of the distributor pipe is encapsulated in an outer casing co-axial with the distributor pipe. A centrifugal channel comprising an inlet for receiving the mixture from the holes of the distributor pipes and an outlet for ejecting the mixture from the flow channel is configured to impart a centrifugal motion to the mixture as it passes through the channel. The vessel comprises a vertical inlet pipe for distribution of crude-water mixture which extends from a bottom centre of the vessel to a height equal to/above the liquid interface of the vessel. The vessel comprises a plurality of horizontal pipes, for distribution of crude-water mixture from the vertical inlet pipes, which divert flows towards the dish ends of the vessel. The horizontal pipes comprise a plurality of holes distributing the crude-water mixture on to the diverting plates. The diverting plates receiving crude-water mixture deviates the mixture into the envelop smoothly. The envelopes provide centrifugal effect to the crude-water mixture before ejecting the mixture into the desalter vessel. The ratio of the inside diameters of inlet distributor pipes and its envelop shall be in the range of 1.5-2.0.
Reference will now be made to a desalter vessel which is explained with the help of figures. The figures are for the purpose of illustration only and should not be construed as limitations on the assembly and mechanism of the present disclosure. Wherever possible, reference numerals will be used to refer to the same or like parts.
Accordingly, figures 1 to 4 illustrate a desalting vessel (100) for crude-water mixture. As shown in figures 1 and 2, the said desalting vessel (100) has a generally cylindrical configuration comprising a hollow internal space for storage of crude-water mixture. The desalter vessel (100) comprises an inlet header (1) having vertical inlet pipe (1a) extending longitudinally towards the hollow internal space from a base region of the said desalter vessel (100). The crude-water mixture enters into the vessel through the inlet header (1). The length and configuration of the inlet header (1) is such that the inlet header (1) extends longitudinally upwards from the bottom centre of the vessel
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to an elevation equal to or just above a pre-defined normal interface level of the desalter vessel. It is known to a skilled person in the art the normal interface level of the desalter vessel can be variable according to different embodiments of the present disclosure. The desalter vessel (100) further comprises a plurality of horizontal inlet distributor headers (2). The said horizontal inlet distributor headers (2) have a plurality of horizontal pipes (2a, 2b) being configured with the inlet header (1) at right angles such that the horizontal pipes (2a, 2b) extend oppositely with respect to each other. The said horizontal pipes (2a, 2b) are configured to distribute the crude-water mixture from the vertical inlet pipe, towards the sides of the desalter vessel (100). The desalter vessel (100) further comprises distributor pipes (3a, 3b) encapsulated by an envelope for receiving the crude-water mixture from the inlet pipe. In a non-limiting embodiment of the present disclosure, the ratio of the inside diameters of the inlet distributor pipes and its envelop shall be in the range of 1.5-2.0. The said distributor pipes (3a, 3b) are configured with the respective horizontal pipes (2a, 2b) respectively at right angles in the same horizontal plane. The said distributor pipes (3a, 3b) are encapsulated in an outer casing co-axial with the distributor pipe. Each of the said distributor pipes (3a, 3b) comprise a plurality of holes (4) for distributing the crude-water mixture from the respective horizontal pipes (2a, 2b) on to respective diverting plates (5a, 5b).
Referring to figures 3 and 4, the desalter vessel comprises centrifugal channels (6a, 6b) corresponding to the diverting plates (5a, 5b). Each of the centrifugal channels (6a, 6b) comprises an inlet for receiving the mixture from the plurality of holes (4) of the distributor pipe and an outlet for ejecting the mixture from the channel. The said desalter vessel (100) further comprises a plurality of electric grids (7) being disposed above the distributor headers (2). A crude outlet (8) for extraction of crude from the vessel is provided in the desalter vessel. The said crude outlet (8) is located at the top centre of the vessel. For the purpose of removal of water from the desalter vessel (100), effluent outlet collector (9) is provided in at the bottom of the desalter vessel.
In an embodiment of the present disclosure, referring to figures 1 to 4, during operation of the said desalter vessel (100), the flow of the crude-water mixture from the vertical pipe (1a) is divided into two parts in the horizontal pipes (2a, 2b) diverting the flow towards the sides of the vessel. The said crude-water mixture is further
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distributed towards the dish ends of the vessels by the horizontaldistributor pipes (3a, 3b), which consist of a plurality of holes (4) to eject the mixture horizontally towards the diverting plates (5a, 5b). In an embodiment, the holes are disposed parallel to the centre line of the vessel and the diverting plates are approximately at an angle of 45 degrees with the holes. Upon discharge from the said holes, the crude-water mixture travels through the centrifugal channel in a circular path creating centrifuge force in the flow. To avoid the crude-water mixture from flowing out of the circular envelop through the ends of the centrifugal channel, end plates (10) are provided. The centrifuge force assists the separation of the different density liquids (i.e. crude and water). Water being heavier is forced towards the wall of centrifugal channels (6a, 6b). This force provides initial separation, in addition to the gravity separation inside the desalter vessel (100). This initial separation increases the overall separation efficiency of the desalter vessel (100).
In another embodiment of the present disclosure, the centrifugal channel shall have an exit angle of X degrees from the vertical axis of the desalter vessel (100). However, the exit angle can be variable in different embodiments of the present disclosure as per the requirements of the user/manufacturer.
List of reference numerals:
100
Desalter Vessel
1
Inlet Header
1a
Vertical Inlet Pipe
2
Distributor Headers
2a, 2b
Horizontal Pipes
3a, 3b
Distributor Pipes
4
Plurality of Holes
5a, 5b
Diverting Plates
6a, 6b
Centrifugal Channels
7
Plurality of Electric Grids
8
Crude Outlet
9
Effluent Outlet Collector
10
End Plates of Centrifugal Channel
9
Equivalents:
With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.
It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “having” should be interpreted as “having at least,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.”
While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and
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embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.
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We Claim:
1. A desalting vessel (100) for crude-water mixture comprising:
an inlet header (1), a crude outlet (8), effluent outlet collector (9), a plurality of electric grids (7) disposed in the vessel;
a plurality of horizontal inlet distributor headers (2) for distributing the crude-water mixture horizontally along the length of the vessel; each of the distributor header comprising of distributor pipes (3a, 3b) with a plurality of holes (4) and centrifugal channels (6a, 6b) and diverting plates (8a, 8b), co-axial with the pipes;
wherein each of the distributor pipe (3a, 3b) is encapsulated by a centrifuge channel, coaxial with the distributor pipe, for receiving the mixture from the inlet pipe;
centrifugal channel (6a, 6b) comprising an inlet for receiving the mixture from the holes (4) of the distributor pipes (3a, 3b) and an outlet for ejecting the mixture through the flow channel is configured to impart a centrifugal motion to the mixture as it passes through the channel.
2. The desalting vessel (100) as claimed in claim 1, wherein the vessel comprises a vertical inlet pipe (1a) for distribution of crude-water mixture which extends from a bottom centre of the vessel to a height equal to/above the liquid interface of the vessel.
3. The desalting vessel (100) as claimed in claim 1, wherein the vessel comprises a plurality of horizontal pipes (2a, 2b), for distribution of crude-water mixture from the vertical inlet pipes, which divert flows towards sides of the vessel.
4. The desalting vessel (100) as claimed in claim 1, wherein the distributor pipes (3a, 3b) comprise the plurality of holes (4) distributing the crude-water mixture on to the diverting plates (5a, 5b).
5. The desalting vessel (100) as claimed in claim 1, wherein the diverting plates (5a, 5b) receiving crude-water mixture deviates the mixture into the envelop smoothly.
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6. The desalting vessel (100) as claimed in claim 1, wherein the centrifugal channels (6a, 6b) provide centrifugal effect to the crude-water mixture before ejecting the mixture into the desalter vessel.
7. The desalting vessel as claimed in claim 1, wherein the ratio of the inside diameters of inlet distributor pipes (3a, 3b) and its envelop shall be in the range of 1.5-2.0.