U.S. patent application number 14/516731 was filed with the patent office on 2015-06-11 for method and device for separating hydrocarbons and contaminants with a surface treatment mechanism.
The applicant listed for this patent is Ransdall K. Smith, Jaime A. Valencia. Invention is credited to Ransdall K. Smith, Jaime A. Valencia.
Application Number | 20150159942 14/516731 |
Document ID | / |
Family ID | 51846989 |
Filed Date | 2015-06-11 |
United States Patent
Application |
20150159942 |
Kind Code |
A1 |
Valencia; Jaime A. ; et
al. |
June 11, 2015 |
METHOD AND DEVICE FOR SEPARATING HYDROCARBONS AND CONTAMINANTS WITH
A SURFACE TREATMENT MECHANISM
Abstract
The disclosure includes a method for separating a feed stream in
a distillation tower may comprise maintaining a controlled freeze
zone section in the distillation tower that forms solids from a
feed stream, wherein the controlled freeze zone section includes
one or more internally disposed elements and a controlled freeze
zone wall having an internal wall surface inside of the
distillation tower, modifying at least one of the internally
disposed elements, the internal wall surface, or both with a
treatment mechanism that includes at least one of (a) removing
portions of the internal wall surface and (b) applying a coating
surface, introducing the feed stream into the controlled freeze
zone section, forming the solids from the feed stream in the
controlled freeze zone section, and at least one of preventing and
destabilizing adhesion of the solids to the internal wall surface
with the treatment mechanism.
Inventors: |
Valencia; Jaime A.;
(Houston, TX) ; Smith; Ransdall K.; (Spring,
TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Valencia; Jaime A.
Smith; Ransdall K. |
Houston
Spring |
TX
TX |
US
US |
|
|
Family ID: |
51846989 |
Appl. No.: |
14/516731 |
Filed: |
October 17, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61912987 |
Dec 6, 2013 |
|
|
|
Current U.S.
Class: |
62/629 |
Current CPC
Class: |
F25J 3/08 20130101; F25J
2200/74 20130101; F25J 2290/40 20130101; F25J 3/0266 20130101; F25J
2200/30 20130101; F25J 3/0233 20130101; B01D 3/32 20130101; C10L
2290/38 20130101; Y02C 20/40 20200801; C10L 3/101 20130101; C10L
3/106 20130101; F25J 2220/66 20130101; C10L 3/107 20130101; F25J
2280/40 20130101; C10L 2290/543 20130101; F25J 3/0635 20130101;
F25J 3/061 20130101; C10L 3/102 20130101; F25J 2205/04 20130101;
F25J 2290/12 20130101; C10L 2290/28 20130101; F25J 2205/20
20130101; C10L 2290/58 20130101; Y02C 10/12 20130101; C07C 7/05
20130101; F25J 2200/50 20130101; F25J 1/0022 20130101; F25J 2290/44
20130101; F25J 2200/02 20130101; F25J 3/0209 20130101; F25J 2235/60
20130101; B01D 3/008 20130101 |
International
Class: |
F25J 3/02 20060101
F25J003/02 |
Claims
1. A method for separating a feed stream in a distillation tower
comprising: maintaining a controlled freeze zone section in the
distillation tower that forms solids from a feed stream, wherein
the controlled freeze zone section includes one or more internally
disposed elements and a controlled freeze zone wall having an
internal wall surface inside of the distillation tower; modifying
at least one of the internally disposed elements, the internal wall
surface, or both with a treatment mechanism that includes at least
one of (a) removing portions of the internal wall surface and (b)
applying a coating surface; introducing the feed stream into the
controlled freeze zone section; forming the solids from the feed
stream in the controlled freeze zone section; and at least one of
preventing and destabilizing adhesion of the solids to the internal
wall surface with the treatment mechanism.
2. The method of claim 1, wherein removing portions of the internal
wall surface comprises one of mechanically and electrochemically
removing material from the internal wall surface.
3. The method of claim 2, wherein mechanically removing material
comprises sanding, grinding, sandblasting, or mechanically
polishing the internal wall surface.
4. The method of claim 2, wherein electrochemically removing
material comprises electropolishing the internal wall surface.
5. The method of claim 1, wherein the coating surface comprises
polytetrafluoroethylene.
6. The method of claim 1, wherein the coating surface comprises an
innermost surface of the internal wall surface within the inside of
the distillation tower.
7. The method of claim 1, further comprising: modifying a surface
of at least one of at least two internally disposed elements with a
treatment mechanism, wherein the two internally disposed elements
comprise a melt tray assembly and a spray assembly, and wherein at
least one of the melt tray assembly and the spray assembly is
separate from the internal wall surface; and at least one of
preventing and destabilizing adhesion of the solids to the at least
one of the melt tray assembly and the spray assembly with the
treatment mechanism.
8. The method of claim 1, further comprising inserting a closing
element having a closing element inner surface into a wall opening
of the controlled freeze zone wall, wherein the inserted closing
element inner surface is substantially flush with the internal wall
surface.
9. A method for producing hydrocarbons comprising: maintaining a
controlled freeze zone section in the distillation tower that forms
solids from a feed stream, wherein the controlled freeze zone
section includes internally disposed elements and a controlled
freeze zone wall having an internal wall surface inside of the
distillation tower; modifying at least one of the elements, the
internal wall surface, or both with a treatment mechanism that
includes at least one of (a) removing portions of the internal wall
surface and (b) applying a coating surface; introducing the feed
stream into the controlled freeze zone section; forming solids from
the feed stream in the controlled freeze zone section; at least one
of preventing and destabilizing adhesion of the solids to the
internal wall surface with the treatment mechanism; and producing
hydrocarbons in the feed stream from the distillation tower.
10. The method of claim 9, wherein removing portions of the
internal wall surface comprises one of mechanically and
electrochemically removing material from the internal wall
surface.
11. The method of claim 10, wherein mechanically removing material
comprises sanding, grinding, sandblasting, or mechanically
polishing the internal wall surface.
12. The method of claim 10, wherein electrochemically removing
material comprises electropolishing the internal wall surface.
13. The method of claim 9, wherein the coating surface comprises
polytetrafluoroethylene.
14. The method of claim 9, wherein the coating surface comprises an
innermost surface of the internal wall surface within the inside of
the distillation tower.
15. The method of claim 9, further comprising: modifying a surface
of at least one of a melt tray assembly and a spray assembly within
the controlled freeze zone section with the treatment mechanism,
wherein at least one of the melt tray assembly and the spray
assembly is separate from the internal wall surface; and at least
one of preventing and destabilizing adhesion of the solids to the
at least one of the melt tray assembly and the spray assembly with
the treatment mechanism.
16. The method of claim 9, further comprising inserting a closing
element having a closing element inner surface into a wall opening
of the controlled freeze zone wall, wherein the inserted closing
element inner surface is substantially flush with the internal wall
surface.
17. A distillation tower that separates a contaminant in a feed
stream from a hydrocarbon in the feed stream, comprising: a
stripper section constructed and arranged to separate a feed
stream, comprising a contaminant and a hydrocarbon, into an
enriched contaminant bottom liquid stream, comprising the
contaminant, and a freezing zone vapor stream, comprising the
hydrocarbon, without forming solids; and a controlled freeze zone
comprising: a spray assembly constructed and arranged to form the
solid; a melt tray assembly constructed and arranged to melt the
solids; an internal wall surface, inside of the distillation tower,
at least one of having a substantially smooth surface and a coating
surface, wherein the coating surface is inside of the distillation
tower and is an outermost surface of the internal wall surface.
18. The distillation tower of claim 17, wherein the controlled
freeze zone wall includes a wall opening that protrudes away from
the inside of the distillation tower.
19. The distillation tower of claim 18, further comprising a
closing element within the wall opening, wherein the closing
element includes a closing element inner surface that is
substantially flush with the internal wall surface.
20. The distillation tower of claim 17, wherein the spray assembly
includes a spray head and a spray nozzle, and wherein at least one
of the spray head and the spray nozzle-have a substantially smooth
surface or a coating surface.
21. The distillation tower of claim 17, further comprising a
rectifier section constructed and arranged to separate the
feedstream without forming solids.
22. The distillation tower of claim 21, wherein at least one of the
stripping section, the controlled freeze zone section and the
rectifier section are in a first vessel and another of the at least
one of the stripping section, the controlled freeze zone section
and the rectifier section are in a second vessel that is separate
from the first vessel.
23. The distillation tower of claim 21, wherein the stripping
section and the controlled freeze zone section are in a first
vessel and the rectifier section is in a second vessel that is
separate from the first vessel.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the priority benefit of both U.S.
Provisional patent application No. 61/912,987 filed on Dec. 6, 2013
entitled METHOD AND DEVICE FOR SEPARATING HYDROCARBONS AND
CONTAMINANTS WITH A SURFACE TREATMENT MECHANISM, the entirety of
which is incorporated by reference herein.
[0002] This application is related to but does not claim priority
to U.S. Provisional patent application No.: 61/912,957 filed on
Dec. 6, 2013 entitled METHOD AND DEVICE FOR SEPARATING HYDROCARBONS
AND CONTAMINANTS WITH A SPRAY ASSEMBLY; 62/044,770 filed on Sep. 2,
2014 entitled METHOD AND DEVICE FOR SEPARATING HYDROCARBONS AND
CONTAMINANTS WITH A SPRAY ASSEMBLY; 61/912,959 filed on Dec. 6,
2013 entitled METHOD AND SYSTEM OF MAINTAINING A LIQUID LEVEL IN A
DISTILLATION TOWER; 61/912,964 filed on Dec. 6, 2013 entitled
METHOD AND DEVICE FOR SEPARATING A FEED STREAM USING RADIATION
DETECTORS; 61/912,970 filed on Dec. 6, 2013 entitled METHOD AND
SYSTEM OF DEHYDRATING A FEED STREAM PROCESSED IN A DISTILLATION
TOWER; 61/912,975 filed on Dec. 6, 2013 entitled METHOD AND SYSTEM
FOR SEPARATING A FEED STREAM WITH A FEED STREAM DISTRIBUTION
MECHANISM; 61/912,978 filed on Dec. 6, 2013 entitled METHOD AND
SYSTEM FOR PREVENTING ACCUMULATION OF SOLIDS IN A DISTILLATION
TOWER; 61/912,983 filed on Dec. 6, 2013 entitled METHOD OF REMOVING
SOLIDS BY MODIFYING A LIQUID LEVEL IN A DISTILLATION TOWER;
61/912,984 filed on Dec. 6, 2013 entitled METHOD AND SYSTEM OF
MODIFYING A LIQUID LEVEL DURING START-UP OPERATIONS; 61/912,986
filed on Dec. 6, 2013 entitled METHOD AND DEVICE FOR SEPARATING
HYDROCARBONS AND CONTAMINANTS WITH A HEATING MECHANISM TO
DESTABILIZE AND/OR PREVENT ADHESION OF SOLIDS.
BACKGROUND
[0003] 1. Fields of Disclosure
[0004] The disclosure relates generally to the field of fluid
separation. More specifically, the disclosure relates to the
cryogenic separation of contaminants, such as acid gas, from a
hydrocarbon.
[0005] 2. Description of Related Art
[0006] This section is intended to introduce various aspects of the
art, which may be associated with the present disclosure. This
discussion is intended to provide a framework to facilitate a
better understanding of particular aspects of the present
disclosure. Accordingly, it should be understood that this section
should be read in this light, and not necessarily as admissions of
prior art.
[0007] The production of natural gas hydrocarbons, such as methane
and ethane, from a reservoir oftentimes carries with it the
incidental production of non-hydrocarbon gases. Such gases include
contaminants, such as at least one of carbon dioxide ("CO.sub.2"),
hydrogen sulfide ("H.sub.2S"), carbonyl sulfide, carbon disulfide
and various mercaptans. When a feed stream being produced from a
reservoir includes these contaminants mixed with hydrocarbons, the
stream is oftentimes referred to as "sour gas."
[0008] Many natural gas reservoirs have relatively low percentages
of hydrocarbons and relatively high percentages of contaminants.
Contaminants may act as a diluent and lower the heat content of
hydrocarbons. Some contaminants, like sulfur-bearing compounds, are
noxious and may even be lethal. Additionally, in the presence of
water some contaminants can become quite corrosive.
[0009] It is desirable to remove contaminants from a stream
containing hydrocarbons to produce sweet and concentrated
hydrocarbons. Specifications for pipeline quality natural gas
typically call for a maximum of 2-4% CO.sub.2 and 1/4 grain
H.sub.2S per 100 scf (4 ppmv) or 5 mg/Nm3 H.sub.2S. Specifications
for lower temperature processes such as natural gas liquefaction
plants or nitrogen rejection units typically require less than 50
ppm CO.sub.2.
[0010] The separation of contaminants from hydrocarbons is
difficult and consequently significant work has been applied to the
development of hydrocarbon/contaminant separation methods. These
methods can be placed into three general classes: absorption by
solvents (physical, chemical and hybrids), adsorption by solids,
and distillation.
[0011] Separation by distillation of some mixtures can be
relatively simple and, as such, is widely used in the natural gas
industry. However, distillation of mixtures of natural gas
hydrocarbons, primarily methane, and one of the most common
contaminants in natural gas, carbon dioxide, can present
significant difficulties. Conventional distillation principles and
conventional distillation equipment are predicated on the presence
of only vapor and liquid phases throughout the distillation tower.
The separation of CO.sub.2 from methane by distillation involves
temperature and pressure conditions that result in solidification
of CO.sub.2 if a pipeline or better quality hydrocarbon product is
desired. The required temperatures are cold temperatures typically
referred to as cryogenic temperatures.
[0012] Certain cryogenic distillations can overcome the above
mentioned difficulties. These cryogenic distillations provide the
appropriate mechanism to handle the formation and subsequent
melting of solids during the separation of solid-forming
contaminants from hydrocarbons. The formation of solid contaminants
in equilibrium with vapor-liquid mixtures of hydrocarbons and
contaminants at particular conditions of temperature and pressure
takes place in a controlled freeze zone section.
[0013] Sometimes solids can adhere to an internal (e.g., controlled
freeze zone wall) of the controlled freeze zone section rather than
falling to the bottom of the controlled freeze zone section.
[0014] The adherence is disadvantageous. The adherence, if
uncontrolled, can interfere with the proper operation of the
controlled freeze zone and the effective separation of methane from
the contaminants.
[0015] A need exists for improved technology to prevent and/or
destabilize any adhesion of solids to surface(s) in the controlled
freeze zone section.
SUMMARY
[0016] The present disclosure provides a device and method for
separating contaminants from hydrocarbons and preventing and/or
destabilizing the adhesion of solids to surface(s) in the
controlled freeze zone section, among other things.
[0017] A method for separating a feed stream in a distillation
tower may comprise maintaining a controlled freeze zone section in
the distillation tower that forms solids from a feed stream,
wherein the controlled freeze zone section includes one or more
internally disposed elements and a controlled freeze zone wall
having an internal wall surface inside of the distillation tower,
modifying at least one of the internally disposed elements, the
internal wall surface, or both with a treatment mechanism that
includes at least one of (a) removing portions of the internal wall
surface and (b) applying a coating surface, introducing the feed
stream into the controlled freeze zone section, forming the solids
from the feed stream in the controlled freeze zone section, and at
least one of preventing and destabilizing adhesion of the solids to
the internal wall surface with the treatment mechanism.
[0018] A method for producing hydrocarbons may comprise maintaining
a controlled freeze zone section in the distillation tower that
forms solids from a feed stream, wherein the controlled freeze zone
section includes internally disposed elements and a controlled
freeze zone wall having an internal wall surface inside of the
distillation tower, modifying at least one of the elements, the
internal wall surface, or both with a treatment mechanism that
includes at least one of (a) removing portions of the internal wall
surface and (b) applying a coating surface, introducing the feed
stream into the controlled freeze zone section, forming solids from
the feed stream in the controlled freeze zone section, at least one
of preventing and destabilizing adhesion of the solids to the
internal wall surface with the treatment mechanism, and producing
hydrocarbons in the feed stream from the distillation tower.
[0019] A distillation tower that separates a contaminant in a feed
stream from a hydrocarbon in the feed stream may comprise a
stripper section constructed and arranged to separate a feed
stream, comprising a contaminant and a hydrocarbon, into an
enriched contaminant bottom liquid stream, comprising the
contaminant, and a freezing zone vapor stream, comprising the
hydrocarbon, without forming solids; and a controlled freeze zone
comprising: a spray assembly constructed and arranged to form the
solid; an internal wall surface, inside of the distillation tower,
at least one of having a substantially smooth surface and a coating
surface, wherein the coating surface is inside of the distillation
tower and is an outermost surface of the internal wall surface.
[0020] The foregoing has broadly outlined the features of the
present disclosure so that the detailed description that follows
may be better understood. Additional features will also be
described herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] These and other features, aspects and advantages of the
disclosure will become apparent from the following description,
appending claims and the accompanying drawings, which are briefly
described below.
[0022] FIG. 1 is a schematic diagram of a tower with sections
within a single vessel.
[0023] FIG. 2 is a schematic diagram of a tower with sections
within multiple vessels.
[0024] FIG. 3 is a schematic diagram of a tower with sections
within a single vessel.
[0025] FIG. 4 is a schematic diagram of a tower with sections
within multiple vessels.
[0026] FIG. 5 is a schematic, cross-sectional diagram of the
controlled freeze zone section of a distillation tower with a
treatment mechanism.
[0027] FIG. 6 is a schematic, cross-sectional diagram of the
controlled freeze zone section of a distillation tower with a
treatment mechanism.
[0028] FIG. 7 is a schematic, cross-section diagram of the
controlled freeze zone section of a distillation tower with a
treatment mechanism and a closing element.
[0029] FIG. 8 is a schematic, cross-section diagram of the
controlled freeze zone section of a distillation tower with a
treatment mechanism and a closing element.
[0030] FIG. 9 is a flowchart of a method within the scope of the
present disclosure.
[0031] It should be noted that the figures are merely examples and
no limitations on the scope of the present disclosure are intended
thereby. Further, the figures are generally not drawn to scale, but
are drafted for purposes of convenience and clarity in illustrating
various aspects of the disclosure.
DETAILED DESCRIPTION
[0032] For the purpose of promoting an understanding of the
principles of the disclosure, reference will now be made to the
features illustrated in the drawings and specific language will be
used to describe the same. It will nevertheless be understood that
no limitation of the scope of the disclosure is thereby intended.
Any alterations and further modifications, and any further
applications of the principles of the disclosure as described
herein are contemplated as would normally occur to one skilled in
the art to which the disclosure relates. It will be apparent to
those skilled in the relevant art that some features that are not
relevant to the present disclosure may not be shown in the drawings
for the sake of clarity.
[0033] As referenced in this application, the terms "stream," "gas
stream," "vapor stream," and "liquid stream" refer to different
stages of a feed stream as the feed stream is processed in a
distillation tower that separates methane, the primary hydrocarbon
in natural gas, from contaminants. Although the phrases "gas
stream," "vapor stream," and "liquid stream," refer to situations
where a gas, vapor, and liquid is mainly present in the stream,
respectively, there may be other phases also present within the
stream. For example, a gas may also be present in a "liquid
stream." In some instances, the terms "gas stream" and "vapor
stream" may be used interchangeably.
[0034] The disclosure relates to a system and method for separating
a feed stream in a distillation tower. The system and method helps
prevent and/or destabilize adhesion of solids in the controlled
freeze zone section of the distillation tower by at least one of
(a) removing portions of a surface within the controlled freeze
zone section and (b) applying a coating surface to surfaces within
the controlled freeze zone section. FIGS. 1-9 of the disclosure
display various aspects of the system and method
[0035] The system and method may separate a feed stream having
methane and contaminants. The system may comprise a distillation
tower 104, 204 (FIGS. 1-4). The distillation tower 104, 204 may
separate the contaminants from the methane.
[0036] The distillation tower 104, 204 may be separated into three
functional sections: a lower section 106, a middle controlled
freeze zone section 108 and an upper section 110. The distillation
tower 104, 204 may incorporate three functional sections when the
upper section 110 is needed and/or desired.
[0037] The distillation tower 104, 204 may incorporate only two
functional sections when the upper section 110 is not needed and/or
desired. When the distillation tower does not include an upper
section 110, a portion of vapor leaving the middle controlled
freeze zone section 108 may be condensed in a condenser 122 and
returned as a liquid stream via a spray assembly 129. Moreover,
lines 18 and 20 may be eliminated, elements 124 and 126 may be one
and the same, and elements 150 and 128 may be one and the same. The
stream in line 14, now taking the vapors leaving the middle
controlled freeze section 108, directs these vapors to the
condenser 122.
[0038] The lower section 106 may also be referred to as a stripper
section. The middle controlled freeze zone section 108 may also be
referred to as a controlled freeze zone section. The upper section
110 may also be referred to as a rectifier section.
[0039] The sections of the distillation tower 104 may be housed
within a single vessel (FIGS. 1 and 3). For example, the lower
section 106, the middle controlled freeze zone section 108, and the
upper section 110 may be housed within a single vessel 164.
[0040] The sections of the distillation tower 204 may be housed
within a plurality of vessels to form a split-tower configuration
(FIG. 2). Each of the vessels may be separate from the other
vessels. Piping and/or another suitable mechanism may connect one
vessel to another vessel. In this instance, the lower section 106,
middle controlled freeze zone section 108 and upper section 110 may
be housed within two or more vessels. For example, as shown in FIG.
2, the upper section 110 may be housed within a single vessel 254
and the lower and middle controlled freeze zone sections 106, 108
may be housed within a single vessel 264. When this is the case, a
liquid stream exiting the upper section 110, may exit through a
liquid outlet bottom 260. The liquid outlet bottom 260 is at the
bottom of the upper section 110. Although not shown, each of the
sections may be housed within its own separate vessel, or one or
more section may be housed within separate vessels, or the upper
and middle controlled freeze zone sections may be housed within a
single vessel and the lower section may be housed within a single
vessel, etc. When sections of the distillation tower are housed
within vessels, the vessels may be side-by-side along a horizontal
line and/or above each other along a vertical line.
[0041] The split-tower configuration may be beneficial in
situations where the height of the distillation tower, motion
considerations, and/or transportation issues, such as for remote
locations, need to be considered. This split-tower configuration
allows for the independent operation of one or more sections. For
example, when the upper section is housed within a single vessel
and the lower and middle controlled freeze zone sections are housed
within a single vessel, independent generation of reflux liquids
using a substantially contaminant-free, largely hydrocarbon stream
from a packed gas pipeline or an adjacent hydrocarbon line, may
occur in the upper section. And the reflux may be used to cool the
upper section, establish an appropriate temperature profile in the
upper section, and/or build up liquid inventory at the bottom of
the upper section to serve as an initial source of spray liquids
for the middle controlled freeze zone section. Moreover, the middle
controlled freeze zone and lower sections may be independently
prepared by chilling the feed stream, feeding it to the optimal
location be that in the lower section or in the middle controlled
freeze zone section, generating liquids for the lower and the
middle controlled freeze zone sections, and disposing the vapors
off the middle controlled freeze zone section while they are off
specification with too high a contaminant content. Also, liquid
from the upper section may be intermittently or continuously
sprayed, building up liquid level in the bottom of the middle
controlled freeze zone section and bringing the contaminant content
in the middle controlled freeze zone section down and near steady
state level so that the two vessels may be connected to send the
vapor stream from the middle controlled freeze zone section to the
upper section, continuously spraying liquid from the bottom of the
upper section into the middle controlled freeze zone section and
stabilizing operations into steady state conditions. The split
tower configuration may utilize a sump of the upper section as a
liquid receiver for the pump 128, therefore obviating the need for
a liquid receiver 126 in FIGS. 1 and 3.
[0042] The system may also include a heat exchanger 100 (FIGS.
1-2). The feed stream 10 may enter the heat exchanger 100 before
entering the distillation tower 104, 204. The feed stream 10 may be
cooled within the heat exchanger 100. The heat exchanger 100 helps
drop the temperature of the feed stream 10 to a level suitable for
introduction into the distillation tower 104, 204.
[0043] The system may include an expander device 102 (FIGS. 1-4).
The feed stream 10 may enter the expander device 102 before
entering the distillation tower 104, 204. The feed stream 10 may be
expanded in the expander device 102 after exiting the heat
exchanger 100. The expander device 102 helps drop the temperature
of the feed stream 10 to a level suitable for introduction into the
distillation tower 104, 204. The expander device 102 may be any
suitable device, such as a valve. If the expander device 102 is a
valve, the valve may be any suitable valve that may aid in cooling
the feed stream 10 before it enters the distillation tower 104,
204. For example, the valve 102 may comprise a Joule-Thompson (J-T)
valve.
[0044] The system may include a feed separator 103 (FIGS. 3-4). The
feed stream may enter the feed separator before entering the
distillation tower 104, 204. The feed separator may separate a feed
stream having a mixed liquid and vapor stream into a liquid stream
and a vapor stream. Lines 12 may extend from the feed separator to
the distillation tower 104, 204. One of the lines 12 may receive
the vapor stream from the feed separator. Another one of the lines
12 may receive the liquid stream from the feed separator. Each of
the lines 12 may extend to the same and/or different sections (i.e.
middle controlled freeze zone, and lower sections) of the
distillation tower 104, 204. The expander device 102 may or may not
be downstream of the feed separator 103. The expander device 102
may comprise a plurality of expander devices 102 such that each
line 12 has an expander device 102.
[0045] The system may include a dehydration unit 261 (FIGS. 1-4).
The feed stream 10 may enter the dehydration unit 261 before
entering the distillation tower 104, 204. The feed stream 10 enters
the dehydration unit 261 before entering the heat exchanger 100
and/or the expander device 102. The dehydration unit 261 removes
water from the feed stream 10 to prevent water from later
presenting a problem in the heat exchanger 100, expander device
102, feed separator 103, or distillation tower 104, 204. The water
can present a problem by forming a separate water phase (i.e., ice
and/or hydrate) that plugs lines, equipment or negatively affects
the distillation process. The dehydration unit 261 dehydrates the
feed stream to a dew point sufficiently low to ensure a separate
water phase does not form at any point downstream during the rest
of the process. The dehydration unit may be any suitable
dehydration mechanism, such as a molecular sieve or a glycol
dehydration unit.
[0046] The systems may include a filtering unit (not shown). The
feed stream 10 may enter the filtering unit before entering the
distillation tower 104, 204. The filtering unit may remove
undesirable contaminants from the feed stream before the feed
stream enters the distillation tower 104, 204. Depending on what
contaminants are to be removed, the filtering unit may be before or
after the dehydration unit 261 and/or before or after the heat
exchanger 100.
[0047] The system may include a line 12 (FIGS. 1-4). The line may
also be referred to as an inlet channel 12. The feed stream 10 may
be introduced into the distillation tower 104, 204 through the line
12. The line 12 may extend to the lower section 106 or the middle
controlled freeze zone section 108 of the distillation tower 104,
204. For example, the line 12 may extend to the lower section 106
such that the feed stream 10 may enter the lower section 106 of the
distillation tower 104, 204 (FIGS. 1-4). The line 12 may directly
or indirectly extend to the lower section 106 or the middle
controlled freeze zone section 108. The line 12 may extend to an
outer surface of the distillation tower 104, 204 before entering
the distillation tower.
[0048] If the system includes the feed separator 103 (FIGS. 3-4),
the line 12 may comprise a plurality of lines 12. Each line may be
the same line as one of the lines that extends from the feed
separator to a specific portion of the distillation tower 104,
204.
[0049] The lower section 106 is constructed and arranged to
separate the feed stream 10 into an enriched contaminant bottom
liquid stream (i.e., liquid stream) and a freezing zone vapor
stream (i.e., vapor stream). The lower section 106 separates the
feed stream at a temperature and pressure at which no solids form.
The liquid stream may comprise a greater quantity of contaminants
than of methane. The vapor stream may comprise a greater quantity
of methane than of contaminants. In any case, the vapor stream is
lighter than the liquid stream. As a result, the vapor stream rises
from the lower section 106 and the liquid stream falls to the
bottom of the lower section 106.
[0050] The lower section 106 may include and/or connect to
equipment that separates the feed stream. The equipment may
comprise any suitable equipment for separating methane from
contaminants, such as one or more packed sections 181, or one or
more distillation trays with perforations downcomers and weirs
(FIGS. 1-4).
[0051] The equipment may include components that apply heat to the
stream to form the vapor stream and the liquid stream. For example,
the equipment may comprise a first reboiler 112 that applies heat
to the stream. The first reboiler 112 may be located outside of the
distillation tower 104, 204. The equipment may also comprise a
second reboiler 172 that applies heat to the stream. The second
reboiler 172 may be located outside of the distillation tower 104,
204. Line 117 may lead from the distillation tower to the second
reboiler 172. Line 17 may lead from the second reboiler 172 to the
distillation tower. Additional reboilers, set up similarly to the
second reboiler described above, may also be used.
[0052] The first reboiler 112 may apply heat to the liquid stream
that exits the lower section 106 through a liquid outlet 160 of the
lower section 106. The liquid stream may travel from the liquid
outlet 160 through line 28 to reach the first reboiler 112 (FIGS.
1-4). The amount of heat applied to the liquid stream by the first
reboiler 112 can be increased to separate more methane from
contaminants. The more heat applied by the reboiler 112 to the
stream, the more methane separated from the liquid contaminants,
though more contaminants will also be vaporized.
[0053] The first reboiler 112 may also apply heat to the stream
within the distillation tower 104, 204. Specifically, the heat
applied by the first reboiler 112 warms up the lower section 106.
This heat travels up the lower section 106 and supplies heat to
warm solids entering a melt tray assembly 139 (FIGS. 1-4) of the
middle controlled freeze zone section 108 so that the solids form a
liquid and/or slurry mix.
[0054] The second reboiler 172 applies heat to the stream within
the lower section 106. This heat is applied closer to the middle
controlled freeze zone section 108 than the heat applied by the
first reboiler 112. As a result, the heat applied by the second
reboiler 172 reaches the middle controlled freeze zone section 108
faster than the heat applied by the first reboiler 112. The second
reboiler 172 also helps with energy integration.
[0055] As a result, the heat applied by the second reboiler 172
reaches the middle controlled freeze zone section 108 faster than
the heat applied by the first reboiler 112. The second reboiler 172
also helps with energy integration.
[0056] The equipment may include one or more chimney assemblies 135
(FIGS. 1-4). While falling to the bottom of the lower section 106,
the liquid stream may encounter one or more of the chimney
assemblies 135.
[0057] Each chimney assembly 135 includes a chimney tray 131 that
collects the liquid stream within the lower section 106. The liquid
stream that collects on the chimney tray 131 may be fed to the
second reboiler 172. After the liquid stream is heated in the
second reboiler 172, the stream may return to the middle controlled
freeze zone section 108 to supply heat to the middle controlled
freeze zone section 108 and/or the melt tray assembly 139.
Unvaporized stream exiting the second reboiler 172 may be fed back
to the distillation tower 104, 204 below the chimney tray 131.
Vapor stream exiting the second reboiler 172 may be routed under or
above the chimney tray 131 when the vapor stream enters the
distillation tower 104, 204.
[0058] The chimney tray 131 may include one or more chimneys 137.
The chimney 137 serves as a channel that the vapor stream in the
lower section 106 traverses. The vapor stream travels through an
opening in the chimney tray 131 at the bottom of the chimney 137 to
the top of the chimney 137. The opening is closer to the bottom of
the lower section 106 than it is to the bottom of the middle
controlled freeze zone section 108. The top is closer to the bottom
of the middle controlled freeze zone section 108 than it is to the
bottom of the lower section 106.
[0059] Each chimney 137 has attached to it a chimney cap 133. The
chimney cap 133 covers a chimney top opening 138 of the chimney
137. The chimney cap 133 prevents the liquid stream from entering
the chimney 137. The vapor stream exits the chimney assembly 135
via the chimney top opening 138.
[0060] After falling to the bottom of the lower section 106, the
liquid stream exits the distillation tower 104, 204 through the
liquid outlet 160. The liquid outlet 160 is within the lower
section 106 (FIGS. 1-2). The liquid outlet 160 may be located at
the bottom of the lower section 106.
[0061] After exiting through the liquid outlet 160, the feed stream
may travel via line 28 to the first reboiler 112. The feed stream
may be heated by the first reboiler 112 and vapor may then re-enter
the lower section 106 through line 30. Unvaporized liquid may
continue out of the distillation process via line 24.
[0062] The system may include an expander device 114 (FIGS. 1-4).
After entering line 24, the heated liquid stream may be expanded in
the expander device 114. The expander device 114 may be any
suitable device, such as a valve. The valve 114 may be any suitable
valve, such as a J-T valve.
[0063] The system may include a heat exchanger 116 (FIGS. 1-4). The
liquid stream heated by the first reboiler 112 may be cooled or
heated by the heat exchanger 116. The heat exchanger 116 may be a
direct heat exchanger or an indirect heat exchanger. The heat
exchanger 116 may comprise any suitable heat exchanger.
[0064] The vapor stream in the lower section 106 rises from the
lower section 106 to the middle controlled freeze zone section 108.
The middle controlled freeze zone section 108 is constructed and
arranged to separate the feed stream 10 introduced into the middle
controlled freeze zone section, or into the top of lower section
106, into a solid and a vapor stream. The solid may be comprised
more of contaminants than of methane. The vapor stream (i.e.,
methane-enriched vapor stream) may comprise more methane than
contaminants.
[0065] The middle controlled freeze zone section 108 includes a
lower section 40 and an upper section 39 (FIG. 5). The lower
section 40 is below the upper section 39. The lower section 40
directly abuts the upper section 39. The lower section 40 is
primarily but not exclusively a heating section of the middle
controlled freeze zone section 108. The upper section 39 is
primarily but not exclusively a cooling section of the middle
controlled freeze zone section 108. The temperature and pressure of
the upper section 39 are chosen so that the solid can form in the
middle controlled freeze zone section 108.
[0066] As shown in FIGS. 5-8, the middle controlled freeze zone
section 108 may comprise an internal wall surface 31. The internal
wall surface 31 is part of the controlled freeze zone wall 46.
[0067] The middle controlled freeze zone section 108 may also
comprise a spray assembly 129. The spray assembly 129 cools the
vapor stream that rises from the lower section 40. The spray
assembly 129 sprays liquid, which is cooler than the vapor stream,
on the vapor stream to cool the vapor stream. The spray assembly
129 is within the upper section 39. The spray assembly 129 is not
within the lower section 40.
[0068] The spray assembly 129 includes one or more spray nozzles
120 (FIGS. 1-4). Each spray nozzle 120 sprays liquid on the vapor
stream. The spray assembly 129 may also include a spray pump 128
(FIGS. 1-4) that pumps the liquid. The spray pump 128 pumps the
liquid to one or more spray heads of spray assembly 129 and/or
spray nozzles. Instead of a spray pump 128, gravity may induce flow
in the liquid.
[0069] The liquid sprayed by the spray assembly 129 contacts the
vapor stream at a temperature and pressure at which solids form.
Solids, containing mainly contaminants, form when the sprayed
liquid contacts the vapor stream. The solids fall toward the melt
tray assembly 139.
[0070] The spray assembly 129 includes the one or more spray heads
35. Each spray nozzle 120 is constructed and arranged to inject the
liquid from the spray assembly 129 into the middle controlled
freeze zone section 108. Each spray head 35 is coupled to one of
the spray nozzles 120.
[0071] The temperature in the middle controlled freeze zone section
108 cools down as the vapor stream travels from the bottom of the
middle controlled freeze zone section 108 to the top of the middle
controlled freeze zone section 108. The methane in the vapor stream
rises from the middle controlled freeze zone section 108 to the
upper section 110. Some contaminants may remain in the methane and
also rise. The contaminants in the vapor stream tend to condense or
solidify with the colder temperatures and fall to the bottom of the
middle controlled freeze zone section 108.
[0072] As shown in FIGS. 5-8, the internal wall surface 31 of the
middle controlled freeze zone section 108 may be modified with a
treatment mechanism 36, 136. The treatment mechanism 36, 136 is
constructed and arranged to prevent and/or destabilize adhesion of
the solid to the controlled freeze zone wall 46. The treatment
mechanism 36, 136 prevents and/or destabilizes adhesion of the
solid by making a surface of the controlled freeze zone wall 46
substantially smooth such that any solid in the middle controlled
freeze zone section 108 cannot adhere to the controlled freeze zone
wall 46. In other words, any protrusions previously on the
controlled freeze zone wall 46 that a solid may latch on to are
smoothed by the treatment mechanism to a point where it is
difficult to impossible for the solid to latch onto the internal
wall surface 31. The treatment mechanism may include at least one
of (a) removing portions of the internal wall surface to obtain a
substantially smooth surface 36 and (b) modifying the internal wall
surface 31 to include a coating surface 136.
[0073] Removing portions of the internal wall surface may include
any treatment mechanism that can obtain a substantially smooth
surface 36. For example, the treatment mechanism may include at
least one of mechanically and electrically removing material from
the internal wall surface 31. Mechanically removing material from
the internal wall surface 31 may, for example, include sanding,
grinding, sandblasting, and/or mechanically polishing the internal
wall surface 31. Electrically removing material from the internal
wall surface 31 may, for example, include electropolishing the
internal wall surface 31 and/or laser ablating the internal wall
surface 31. When the internal wall surface 31 is electropolished,
an electrically-conductive solution may be held against the
internal wall surface 31 while electric current passes through the
electrically-conductive solution. The electropolishing may remove
peaks of internal wall surface 31 from the internal wall surface 31
on a microscopic scale. Electrically removing the material may be
preferred to mechanically removing the material because it may be
easier to obtain a substantially smooth surface 36 that is a
homogenously smooth surface. Regardless of the mechanism, the
mechanism involves removing a fine layer of molecules, and
particularly protruding molecules, of the internal wall surface 31
to obtain an internal wall surface 31 that is smooth. The obtained
internal wall surface 31, such as in the case of electrically
removing the material, may also have a nearly mirror-finish
surface. The obtained smooth surface is so smooth that it is hard
for a solid to adhere to the internal wall surface 31.
[0074] The coating surface 136 is part of the internal wall surface
31. The coating surface 136 may be any suitable coating surface
that can withstand cryogenic temperatures. The coating surface 136
may be any suitable coating surface that provides non-stick
characteristics. For example, the coating surface 136 may be
polytetrafluoroethylene. Polytetrafluorethylene may be a good
coating surface because it's considered to be low energy and can be
made very smooth. Specifically, it does not easily attract to other
components so it's harder for other components to adhere to it.
Once applied, the coating surface 136 may be the innermost surface
of the internal wall surface 31 within the inside of the
distillation tower 104, 204. The coating surface 136 may be any
suitable thickness. For example, the coating thickness 136 may be
100 microns to 300 microns or about 100 microns to 300 microns.
Alternatively, the coating thickness 136 may be 100 microns to 1 mm
or about 100 microns to 1 mm.
[0075] As shown in FIGS. 7-8, the controlled freeze zone wall 46
may include a wall opening 57. The wall opening 57 may protrude
(i.e., extending away from the longitudinal axis of the
distillation tower 104, 204) away from the internal wall surface
31. Solids may build-up in and around the wall opening 57; solids
may latch onto the wall opening 57 and/or the area immediately
around the wall opening 57. To prevent the build-up of solids in
and around the wall opening 57, the middle controlled freeze zone
section 108 may include an insert or closing element 55.
[0076] The closing element 55 may be any suitable shape that can
fit within the wall opening 57 and whose closing element inner
surface 56 is substantially flush with the internal wall surface
31. The closing element inner surface 56 is the outermost surface
of the closing element 55 within the inside of the distillation
tower 104, 204. The closing element inner surface 56 is smooth
enough to prevent and/or destabilize the adhesion of a solid. To be
smooth enough, any suitable mechanism may be used on the closing
element inner surface 56. For example, the closing element inner
surface 56 may be coated with a coating surface, such as the
coating surface previously described, or portions of the closing
element inner surface 56 may be removed, such as by using any of
the mechanical and electrical surface treatment means previously
described.
[0077] In addition to including the internal wall surface 31
modified by the treatment mechanism, one or more internally
disposed elements within the middle controlled freeze zone section
108 may be modified with the treatment mechanism. Internally
disposed elements within the middle controlled freeze zone section
108 may include the spray assembly 129, the melt tray assembly 139,
instruments, sensors, etc. Internally disposed elements within the
middle controlled freeze zone section 108 are separate components
from the internal wall surface 31. To modify the one or more
internally disposed elements, an internally disposed element
surface of each internally disposed element may be modified by the
treatment mechanism. The internally disposed element surface may be
an outer surface of the internally disposed element. Once the
internally disposed element surface is modified, the internally
disposed element surface may be a substantially smooth surface such
that any solids in the middle controlled freeze zone section 108
cannot latch on to the internally disposed element. The
substantially smooth surface may be a homogenously smooth
surface.
[0078] When the internal wall surface 31 is modified by the
treatment mechanism, the middle controlled freeze zone section 108
may or may not include a heating mechanism, such as the heating
mechanism described in the application entitled "Method and Device
for Separating Hydrocarbons and Contaminants with a Heating
Mechanism to Destabilize and/or Prevent Adhesion of Solids" by
Jaime Valencia, et al. and filed on the same day as the instant
application. The modified internal wall surface 31 may adequately
prevent and/or destabilize the adhesion of solids to the controlled
freeze zone wall 46 without the heating mechanism. If the modified
internal wall surface 31 is modified by a treatment mechanism that
comprises a coating surface, the modified internal wall surface 31
may act as an insulator to the heat being conducted from outside of
the distillation tower 104, 204. Nevertheless, the heating
mechanism, in this instance, may be turned on if the surface
modified by the treatment mechanism does not prevent solid
build-up.
[0079] The middle controlled freeze zone section 108 may comprise a
melt tray assembly 139 that is maintained in the middle controlled
freeze zone section 108 (FIGS. 1-5). The melt tray assembly 139 is
within the lower section 40 of the middle controlled freeze zone
section 108. The melt tray assembly 139 is not within the upper
section 39 of the middle controlled freeze zone section 108.
[0080] The melt tray assembly 139 is constructed and arranged to
melt a solid formed in the middle controlled freeze zone section
108. When the warm vapor stream rises from the lower section 106 to
the middle controlled freeze zone section 108, the vapor stream
immediately encounters the melt tray assembly 139 and supplies heat
to melt the solid. The melt tray assembly 139 may comprise at least
one of a melt tray 118, a bubble cap 132, a liquid 130 and heat
mechanism(s) 134.
[0081] The melt tray 118 may collect a liquid and/or slurry mix.
The melt tray 118 divides at least a portion of the middle
controlled freeze zone section 108 from the lower section 106.
Consequently, the melt tray 118 is at the bottom 45 of the middle
controlled freeze zone section 108.
[0082] One or more bubble caps 132 may act as a channel for the
vapor stream rising from the lower section 106 to the middle
controlled freeze zone section 108. The bubble cap 132 may provide
a path for the vapor stream up the riser 140 and then down and
around the riser 140 to the melt tray 118. The riser 140 is covered
by a cap 141. The cap 141 prevents the liquid 130 from travelling
into the riser and it also helps prevent solids from travelling
into the riser 140. The vapor stream's traversal through the bubble
cap 132 allows the vapor stream to transfer heat to the liquid 130
within the melt tray assembly 139.
[0083] One or more heat mechanisms 134 may further heat up the
liquid 130 to facilitate melting of the solids into a liquid and/or
slurry mix. The heat mechanism(s) 134 may be located anywhere
within the melt tray assembly 139. For example, as shown in FIGS.
1-4, a heat mechanism 134 may be located around bubble caps 132.
The heat mechanism 134 may be any suitable mechanism, such as a
heat coil. The heat source of the heat mechanism 134 may be any
suitable heat source.
[0084] The liquid 130 in the melt tray assembly is heated by the
vapor stream. The liquid 130 may also be heated by the one or more
heat mechanisms 134. The liquid 130 helps melt the solids formed in
the middle controlled freeze zone section 108 into a liquid and/or
slurry mix. Specifically, the heat transferred by the vapor stream
heats up the liquid, thereby enabling the heat to melt the solids.
The liquid 130 is at a level sufficient to melt the solids.
[0085] The solids form the liquid and/or slurry mix when in the
liquid 130. The liquid and/or slurry mix flows from the middle
controlled freeze zone section 108 to the lower distillation
section 106. The liquid and/or slurry mix flows from the bottom of
the middle controlled freeze zone section 108 to the top of the
lower section 106 via a line 22 (FIGS. 1-4). The line 22 may be an
exterior line. The line 22 may extend from the distillation tower
104, 204. The line 22 may extend from the middle controlled freeze
zone section 108. The line may extend to the lower section 106. The
line 22 may extend from an outer surface of the distillation tower
104, 204.
[0086] The vapor stream that rises in the middle controlled freeze
zone section 108 and does not form solids or otherwise fall to the
bottom of the middle controlled freeze zone section 108, rises to
the upper section 110. The upper section 110 operates at a
temperature and pressure and contaminant concentration at which no
solid forms. The upper section 110 is constructed and arranged to
cool the vapor stream to separate the methane from the
contaminants. Reflux in the upper section 110 cools the vapor
stream. The reflux is introduced into the upper section 110 via
line 18. Line 18 may extend to the upper section 110. Line 18 may
extend from an outer surface of the distillation tower 104,
204.
[0087] After contacting the reflux in the upper section 110, the
feed stream forms a vapor stream and a liquid stream. The vapor
stream mainly comprises methane. The liquid stream comprises
relatively more contaminants. The vapor stream rises in the upper
section 110 and the liquid falls to a bottom of the upper section
110.
[0088] To facilitate separation of the methane from the
contaminants when the stream contacts the reflux, the upper section
110 may include one or more mass transfer devices 176. Each mass
transfer device 176 helps separate the methane from the
contaminants. Each mass transfer device 176 may comprise any
suitable separation device, such as a tray with perforations, or a
section of random or structured packing to facilitate contact of
the vapor and liquid phases.
[0089] After rising, the vapor stream may exit the distillation
tower 104, 204 through line 14. The line 14 may emanate from an
upper part of the upper section 110. The line 14 may extend from an
outer surface of the upper section 110.
[0090] From line 14, the vapor stream may enter a condenser 122.
The condenser 122 cools the vapor stream to form a cooled stream.
The condenser 122 at least partially condenses the stream.
[0091] After exiting the condenser 122, the cooled stream may enter
a separator 124. The separator 124 separates the vapor stream into
liquid and vapor streams. The separator may be any suitable
separator that can separate a stream into liquid and vapor streams,
such as a reflux drum.
[0092] Once separated, the vapor stream may exit the separator 124
as sales product. The sales product may travel through line 16 for
subsequent sale to a pipeline and/or condensation to be liquefied
natural gas.
[0093] Once separated, the liquid stream may return to the upper
section 110 through line 18 as the reflux. The reflux may travel to
the upper section 110 via any suitable mechanism, such as a reflux
pump 150 (FIGS. 1 and 3) or gravity (FIGS. 2 and 4).
[0094] The liquid stream (i.e., freezing zone liquid stream) that
falls to the bottom of the upper section 110 collects at the bottom
of the upper section 110. The liquid may collect on tray 183 (FIGS.
1 and 3) or at the bottom most portion of the upper section 110
(FIGS. 2 and 4). The collected liquid may exit the distillation
tower 104, 204 through line 20 (FIGS. 1 and 3) or outlet 260 (FIGS.
2 and 4). The line 20 may emanate from the upper section 110. The
line 20 may emanate from a bottom end of the upper section 110. The
line 20 may extend from an outer surface of the upper section
110.
[0095] The line 20 and/or outlet 260 connect to a line 41. The line
41 leads to the spray assembly 129 in the middle controlled freeze
zone section 108. The line 41 emanates from the holding vessel 126.
The line 41 may extend to an outer surface of the middle controlled
freeze zone section 108.
[0096] The line 20 and/or outlet 260 may directly or indirectly
(FIGS. 1-4) connect to the line 41. When the line 20 and/or outlet
260 directly connect to the line 41, the liquid spray may be sent
to the spray nozzle(s) 120 via any suitable mechanism, such as the
spray pump 128 or gravity. When the line 20 and/or outlet 260
indirectly connect to the line 41, the lines 20, 41 and/or outlet
260 and line 41 may directly connect to a holding vessel 126 (FIGS.
1 and 3). The holding vessel 126 may house at least some of the
liquid spray before it is sprayed by the nozzle(s). The liquid
spray may be sent from the holding vessel 126 to the spray
nozzle(s) 120 via any suitable mechanism, such as the spray pump
128 (FIGS. 1-4) or gravity. The holding vessel 126 may be needed
when there is not a sufficient amount of liquid stream at the
bottom of the upper section 110 to feed the spray nozzles 120.
[0097] A method for separating a feed stream 10 in the distillation
tower 104, 204 and/or producing hydrocarbons may include
maintaining the lower section 106 in the distillation tower that
separates the feed stream 10 into the enriched contaminant bottom
liquid stream and the freezing zone vapor stream; maintaining the
middle controlled freeze zone section 108 in the distillation tower
501 that applies the freezing zone liquid stream to form the solid
and the hydrocarbon-enriched vapor stream 501 (FIG. 9); and
modifying the internal wall surface 31 with the treatment mechanism
502 and preventing and/or destabilizing adhesion of the solid to
the internal wall surface 31, 506 (FIG. 9). The method may include
introducing 503 the feed stream 10 into a section 106, 108 of the
distillation tower 104, 204 (FIG. 9). As previously discussed in
the instant application, the feed stream 10 is introduced into one
of the sections 106, 108 via line 12. The method may include
separating the feed stream 10 in the lower section 106 into the
enriched contaminant bottom liquid stream and the freezing zone
vapor stream at a temperature and pressure at which substantially
no solid forms. The lower section 106 operates as previously
discussed in the instant application. The method may include
forming the solids 504 from the feed stream in the controlled
freeze zone section 108. The solids may form when the freezing zone
vapor stream and the freezing zone liquid stream are injected into
the middle controlled freeze zone section 108 at a temperature and
pressure at which the solid and the hydrocarbon-enriched vapor
stream form. The method may include mixing the freezing zone liquid
stream with the freezing zone vapor stream in the controlled freeze
zone section to form the solid and the hydrocarbon-enriched vapor
stream. The middle controlled freeze zone section 108 operates as
previously discussed in the instant application. The method may
include introducing the feed stream 503 into one of the lower
section 106 and the middle controlled freeze zone section 108. The
method may include separating the feed stream 504 in the lower
section 106 into the enriched contaminant bottom liquid stream and
the freezing zone vapor stream. The method may include injecting
the freezing zone vapor stream 505 into the middle controlled
freeze zone section 108 at a temperature and pressure at which the
solid and the hydrocarbon-enriched vapor stream form. The method
may include preventing and/or destabilizing adhesion of the solid
from the middle controlled freeze zone section 506 (FIG. 9).
[0098] The method may include maintaining an upper section 110. The
upper section 110 operates as previously discussed in the instant
application. The method may also include separating the feed stream
in the upper section 110 as previously discussed in the instant
application.
[0099] The method may include sending the hydrocarbon-enriched
stream to a pipeline for sale after it exits the distillation tower
104, 204 via the middle controlled freeze zone section 108 or upper
section 110. The method may include sending the
hydrocarbon-enriched stream to an LNG plant after the
hydrocarbon-enriched stream is processed to include less than 50
ppm of CO.sub.2 in the distillation tower 104, 204. This stream may
be sent to the LNG plant after exiting the distillation tower 104,
204 via the upper section. The method may include removing the
CO.sub.2 enriched stream from the lower section 106 and injecting
the CO.sub.2 enriched stream downhole for disposal, or selling the
CO.sub.2 enriched stream for EOR purposes assuming this stream does
not contain too much H.sub.2S.
[0100] It is important to note that the steps depicted in FIG. 9
are provided for illustrative purposes only and a particular step
may not be required to perform the inventive methodology. Moreover,
FIG. 9 may not illustrate all the steps that may be performed. The
claims, and only the claims, define the inventive system and
methodology.
[0101] Disclosed aspects may be used in hydrocarbon management
activities. As used herein, "hydrocarbon management" or "managing
hydrocarbons" includes hydrocarbon extraction, hydrocarbon
production, hydrocarbon exploration, identifying potential
hydrocarbon resources, identifying well locations, determining well
injection and/or extraction rates, identifying reservoir
connectivity, acquiring, disposing of and/or abandoning hydrocarbon
resources, reviewing prior hydrocarbon management decisions, and
any other hydrocarbon-related acts or activities. The term
"hydrocarbon management" is also used for the injection or storage
of hydrocarbons or CO.sub.2, for example the sequestration of
CO.sub.2, such as reservoir evaluation, development planning, and
reservoir management. The disclosed methodologies and techniques
may be used in extracting hydrocarbons from a subsurface region and
processing the hydrocarbons. Hydrocarbons and contaminants may be
extracted from a reservoir and processed. The hydrocarbons and
contaminants may be processed, for example, in the distillation
tower previously described. After the hydrocarbons and contaminants
are processed, the hydrocarbons may be extracted from the
processor, such as the distillation tower, and produced. The
contaminants may be discharged into the Earth, etc. For example,
the method for producing hydrocarbons may also include removing the
hydrocarbon-enriched vapor stream from the distillation tower. The
method may also include producing 508 hydrocarbons in the feed
stream from the distillation tower (FIG. 9). The initial
hydrocarbon extraction from the reservoir may be accomplished by
drilling a well using hydrocarbon drilling equipment. The equipment
and techniques used to drill a well and/or extract these
hydrocarbons are well known by those skilled in the relevant art.
Other hydrocarbon extraction activities and, more generally, other
hydrocarbon management activities, may be performed according to
known principles.
[0102] As utilized herein, the terms "approximately," "about,"
"substantially," and similar terms are intended to have a broad
meaning in harmony with the common and accepted usage by those of
ordinary skill in the art to which the subject matter of this
disclosure pertains. It should be understood by those of skill in
the art who review this disclosure that these terms are intended to
allow a description of certain features described and claimed
without restricting the scope of these features to the precise
numeral ranges provided. Accordingly, these terms should be
interpreted as indicating that insubstantial or inconsequential
modifications or alterations of the subject matter described are
considered to be within the scope of the disclosure.
[0103] For the purpose of this disclosure, the term "coupled" means
the joining of two members directly or indirectly to one another.
Such joining may be stationary or moveable in nature. Such joining
may be achieved with the two members or the two members and any
additional intermediate members being integrally formed as a single
unitary body with one another or with the two members or the two
members and any additional intermediate members being attached to
one another. Such joining may be permanent in nature or may be
removable or releasable in nature.
[0104] It should be understood that numerous changes,
modifications, and alternatives to the preceding disclosure can be
made without departing from the scope of the disclosure. The
preceding description, therefore, is not meant to limit the scope
of the disclosure. Rather, the scope of the disclosure is to be
determined only by the appended claims and their equivalents. It is
also contemplated that structures and features in the present
examples can be altered, rearranged, substituted, deleted,
duplicated, combined, or added to each other.
[0105] The articles "the", "a" and "an" are not necessarily limited
to mean only one, but rather are inclusive and open ended so as to
include, optionally, multiple such elements.
* * * * *