U.S. patent application number 17/224682 was filed with the patent office on 2021-10-07 for flexible installation of a hydrocarbon liquefaction unit.
The applicant listed for this patent is L'Air Liquide, Societe Anonyme pour l'Etude et l'Exploitation des Procedes Georges Claude. Invention is credited to Oriane FARGES, Yoland PLAMONDON, Christophe SZAMLEWSKI.
Application Number | 20210310731 17/224682 |
Document ID | / |
Family ID | 1000005585389 |
Filed Date | 2021-10-07 |
United States Patent
Application |
20210310731 |
Kind Code |
A1 |
FARGES; Oriane ; et
al. |
October 7, 2021 |
FLEXIBLE INSTALLATION OF A HYDROCARBON LIQUEFACTION UNIT
Abstract
Natural gas liquefaction unit including at least one cryogenic
cold box having at least one heat exchanger; a fixed assembly zone
on its outer wall; at least one closed loop nitrogen refrigeration
cycle; at least one device for equipment required for implementing
the liquefaction of a natural gas stream from a hydrocarbon supply
stream; at least one interconnection module comprising a pipe
holder means and a set of pipes and valves, designed to connect
said at least one cold box to at least one equipment device for the
cycle for refrigerating and/or separating C6+ type hydrocarbon
elements contained in the natural gas, wherein the interconnection
module rests on a frame allowing it to be handled and is connected
to the cold box and to the other method or equipment sub-assemblies
located around said fixed assembly zone.
Inventors: |
FARGES; Oriane; (Houston,
TX) ; PLAMONDON; Yoland; (Montreal, CA) ;
SZAMLEWSKI; Christophe; (Combs la Ville, FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
L'Air Liquide, Societe Anonyme pour l'Etude et l'Exploitation des
Procedes Georges Claude |
Paris |
|
FR |
|
|
Family ID: |
1000005585389 |
Appl. No.: |
17/224682 |
Filed: |
April 7, 2021 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F25J 1/0022 20130101;
F25J 3/0247 20130101; F25J 2240/40 20130101; F25J 2230/32 20130101;
F25J 1/0238 20130101; F25J 2230/60 20130101; F25J 2230/24 20130101;
F25J 1/0259 20130101; F25J 1/0222 20130101 |
International
Class: |
F25J 1/02 20060101
F25J001/02; F25J 1/00 20060101 F25J001/00; F25J 3/02 20060101
F25J003/02 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 7, 2020 |
FR |
2003456 |
Claims
1. Natural gas liquefaction unit comprising: at least one cryogenic
cold box (2) comprising: at least one heat exchanger; a fixed
assembly zone (8) on its outer wall; at least one closed loop
nitrogen refrigeration cycle; at least one device (3) for equipment
required for implementing the liquefaction of a natural gas stream
from a hydrocarbon supply stream; at least one interconnection
module (4) comprising a pipe holder means and a set of pipes and
valves (5, 6, 7), designed to connect said at least one cold box
(2) to at least one equipment device for the cycle for
refrigerating and/or separating C6+ type hydrocarbon elements
contained in the natural gas, characterized in that the
interconnection module (4) rests on a frame allowing it to be
handled and is connected to the cold box (2) and to the other
method or equipment sub-assemblies (3) located around said fixed
assembly zone (8).
2. Unit according to the preceding claim, characterized in that the
interconnection module (4) particularly comprises one or more
elements selected from among control valves, manual valves, sample
connections, pipes, pre-cut panels with valve actuators,
instruments, vapour sources, lighting, ladders and platforms,
pre-wired junction boxes, platforms for instrument/electric cables,
pipe supports, channeling.
3. Unit according to claim 2, characterized in that the
interconnection module (4) comprises one or more elements selected
from among control valves, manual valves, valve actuators.
4. Unit according to one of the preceding claims, characterized in
that said other method or equipment sub-assemblies (3) are required
to implement at least one method function selected from among the
compression of the nitrogen of the refrigeration cycle, the
overpressurization of the nitrogen of the refrigeration cycle, the
expansion of the nitrogen of the refrigeration cycle, the cooling
of the nitrogen of the refrigeration cycle, the liquefaction of the
natural gas stream, the separation of the C6+ type hydrocarbons
contained in the natural gas, the interconnection module (4) being
devoid of such method or equipment sub-assemblies.
5. Unit according to one of the preceding claims, characterized in
that the refrigeration cycle comprises a first means for
compressing the nitrogen of the refrigeration cycle, a means for
cooling the nitrogen of the refrigeration cycle, a second means for
compressing the nitrogen of the refrigeration cycle, said second
compression means comprising two booster compressors coupled to two
respective expansion means, said booster compressors being
configured to compress the nitrogen of the refrigeration cycle at
an identical pressure.
6. Unit according to one of the preceding claims, characterized in
that said frame has a metal structure.
7. Unit according to one of the preceding claims, characterized in
that said at least one heat exchanger is a brazed aluminium heat
exchanger.
8. Use of a unit as defined in one of the preceding claims for
liquefying a natural gas stream.
9. Method for starting a liquefaction unit as defined in claims 1
to 6, comprising the following steps: on-site installation of a
closed loop nitrogen refrigeration cycle and of a cold box (2)
comprising: at least one heat exchanger; a fixed assembly zone (8)
on its outer wall; on-site installation of an interconnection
module (4) comprising a pipe holder means and a set of pipes and
valves (5, 6, 7), designed to connect said at least one cold box
(2) to at least one equipment device (3) for the cycle for
refrigerating and/or separating C6+ type hydrocarbon elements
contained in the natural gas; fixing said interconnection module
(4) to the cold box (2) and to at least one equipment device (3),
allowing the implementation of the liquefaction method using said
cold box (2), already available on the site.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of priority under 35
U.S.C. .sctn. 119 (a) and (b) to French Patent Application No.
2003456, filed Apr. 7, 2020, the entire contents of which are
incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The technical field of the invention is that of the
liquefaction of natural gas using a nitrogen refrigeration
cycle.
[0003] The present invention relates to an installation of a
natural gas liquefaction unit using a nitrogen refrigeration cycle
and its unit.
BACKGROUND OF THE INVENTION
[0004] Natural gas liquefaction methods need to be used in order to
reduce the environmental impact. Market developments promote the
use of liquefiers close to public areas in order to ensure more
efficient management of deliveries. The available land is generally
small and must meet strict environmental restrictions.
[0005] Commonly, this type of unit uses mixed coolants that are
mixtures of gas with high yields for the liquefaction of natural
gas. However, their hazardousness results in factory configurations
that are very spread out with a very high societal risk. The
invention defines the design of Natural Gas liquefiers using a
nitrogen refrigeration cycle called Turbofin.TM..
SUMMARY OF THE INVENTION
[0006] The invention offers a solution to the aforementioned
problems. An aspect of the invention relates to a natural gas
liquefaction unit comprising: [0007] at least one cryogenic cold
box comprising: [0008] at least one heat exchanger; [0009] a fixed
assembly zone on its outer wall; [0010] at least one closed loop
nitrogen refrigeration cycle; [0011] at least one device for
equipment required for implementing the liquefaction of a natural
gas stream from a hydrocarbon supply stream; [0012] at least one
interconnection module comprising a pipe holder means and a set of
pipes and valves, designed to connect said at least one cold box to
at least one equipment device for the cycle for refrigerating
and/or separating C6+ type hydrocarbon elements contained in the
natural gas; characterized in that the interconnection module rests
on a frame allowing it to be handled and is connected to the cold
box and to the other method or equipment sub-assemblies located
around said fixed assembly zone.
[0013] According to other embodiments, the present invention also
relates to: [0014] a unit as defined above, characterized in that
the interconnection module particularly comprises one or more
elements selected from among control valves, manual valves, sample
connections, pipes, pre-cut panels with valve actuators,
instruments, vapour sources, lighting, ladders and platforms,
pre-wired junction boxes, platforms for instrument/electric cables,
pipe supports, channeling; [0015] a unit as defined above,
characterized in that the interconnection module comprises one or
more elements selected from among control valves; manual valves,
valve actuators; [0016] a unit as defined above, characterized in
that said other method or equipment sub-assemblies are required to
implement at least one method function selected from among the
compression of the nitrogen of the refrigeration cycle, the
overpressurization of the nitrogen of the refrigeration cycle, the
expansion of the nitrogen of the refrigeration cycle, the cooling
of the nitrogen of the refrigeration cycle, the liquefaction of the
natural gas stream, the separation of the C6+ type hydrocarbons
contained in the natural gas, the interconnection module being
devoid of such method or equipment sub-assemblies. In other words,
the interconnection module does not comprise any method or
equipment sub-assembly as defined above. In particular, the
interconnection module is devoid of a separator module; [0017] a
unit as defined above, characterized in that the refrigeration
cycle comprises a first means for compressing the nitrogen of the
refrigeration cycle, a means for cooling the nitrogen of the
refrigeration cycle, a second means for compressing the nitrogen of
the refrigeration cycle, said second compression means comprising
two booster compressors coupled to two respective expansion means,
said booster compressors being configured to compress the nitrogen
of the refrigeration cycle at an identical pressure; [0018] a unit
as defined above, characterized in that said frame has a metal
structure; [0019] a unit as defined above, characterized in that
said at least one heat exchanger is a brazed aluminium heat
exchanger; [0020] the use of a unit as defined above for liquefying
a natural gas stream.
[0021] A method for starting a liquefaction unit as defined above,
comprising the following steps: [0022] on-site installation of a
closed loop nitrogen refrigeration cycle and of a cold box
comprising: [0023] at least one heat exchanger; [0024] a fixed
assembly zone on its outer wall; [0025] on-site installation of an
interconnection module comprising a pipe holder means and a set of
pipes and valves, designed to connect said at least one cold box to
at least one equipment device for the cycle for refrigerating
and/or separating C6+ type hydrocarbon elements contained in the
natural gas, [0026] fixing said interconnection module to the cold
box and to at least one equipment device, allowing the
implementation of the liquefaction method using said cold box,
already available on the site.
[0027] The natural gas is composed of different gases with
different physical features, Nitrogen is a pure substance and does
not allow all the compounds of the natural gas to be tracked for
the liquefaction thereof. However, the method allows the use of the
"compression-expansion" principle and therefore allows cold
production with high liquefaction yields.
[0028] The method is composed of two main parts. The cold creation
part identified by the name `nitrogen cycle` and the natural gas
liquefaction part. A nitrogen refrigeration cycle is understood to
be a cycle in which the coolant is nitrogen, contrary to the cycles
with mixed coolants, in which the coolant is a mixture of different
constituent elements, in particular a mixture of hydrocarbons.
[0029] The nitrogen cycle is a closed loop. The natural gas only
passes through the liquefaction zone, called cold box. The nitrogen
of the cycle is compressed in a compressor, then cooled, before
being compressed a second time, by two boosters, or booster
compressors, coupled to two separate turbines.
[0030] Preferably, the output pressure of the two boosters of the
turbines is identical. Contrary to the configurations in which the
outputs of the cold and hot turbines have different pressures and
are therefore compressed at two different stages of the cycle
compressor, this allows only a single suction pressure to be
processed, which simplifies the architecture of the unit and
improves its operational efficiency, by simplifying the operating
and maintenance operations.
[0031] The nitrogen is then pre-cooled before being expanded to
create two different cold temperatures. These two latter
temperatures correspond to two liquefaction temperatures. Said
temperatures themselves correspond to two average temperatures for
liquefaction of the gases composed of the natural gas.
[0032] Each compression stage corresponds to the heating of the
gas. In order to optimize the next compression, the gas must be
pre-cooled using equipment called "refrigerators", operating by
exchanging with air or with water.
[0033] The consequence of this type of liquefaction is the
significant number of connections connecting the equipment to each
other. This configuration results in a significant cost compared to
the size of the liquefaction cycle.
[0034] The liquefaction comprises one or more exchangers, as well
as, in general, an element allowing separation of the heavy C6+
type hydrocarbon components contained in the natural gas. The gas
that is thus purified, basically composed of methane, is recovered
in order to be liquefied through exchangers located in said cold
box. The aforementioned separation equipment is located in the same
insulating assembly, called cold box.
[0035] The liquefaction assembly called cold box can, as a function
of the liquefaction volumes, be composed of one or more cold boxes.
These can be vertical or horizontal.
[0036] The aforementioned equipment and/or sub-assemblies are
located around a distribution module comprising all the connections
between all the equipment that are required for the method, as well
as the connections to the outside of the liquefaction assembly. AH
the elements allowing the measurements and the liquefaction
assembly to be controlled are also located in this sub-assembly,
called central module.
[0037] The machines called turbine/booster machines may or may not
be, as a function of their capacities, located on the same support
structure.
[0038] Each of these satellite modules comprises the method
function for which it has been identified, as well as the elements
allowing it to be controlled and enabling its intrinsic safety.
[0039] The connection between the central module and the satellites
is adapted for each project condition and/or for each physical
variation of each of these satellite modules.
[0040] The present invention allows the interconnection zone to be
defined as a central distribution module between all the method
modules. This can cover the equipment associated with the method or
other modules comprising method sub-assemblies. These other method
or equipment sub-assemblies are those that are configured to
implement method functions that are required for implementing the
cold fluid required for the liquefaction of a natural gas stream.
The method functions are clearly separate from each other, as well
as from those that are associated with the designs of each
supplier, and the interconnection allows the possibility of
changing suppliers without necessarily changing the circulation of
the fluids. The connections are adapted to the modules during the
on-site assembly.
[0041] In order to meet this requirement, the sub-assemblies and
satellite equipment are designed to be autonomous and independent
from a method perspective, but also to be mechanical.
[0042] The present invention allows a natural gas liquefaction
installation to be provided using a nitrogen cooling cycle that
adapts to the environment in a manner that is simple and is the
least expensive, By virtue of the invention, the system allows a
flexible arrangement to be proposed for the installation as a
function of the environment.
[0043] This also makes it possible to ensure the effectiveness of
the method irrespective of the type of hydrocarbon, in particular
natural gas.
[0044] This also makes it possible to guarantee construction with a
manageable cost, since the modules can be constructed in the
factory and delivered directly to the site, while being able to be
adapted to the environment of the site.
[0045] A cold box integrates one or more heat exchangers in an
insulating enclosure that is generally made of steel or of carbon.
The cold box combines the exchangers with their associated
cryogenic equipment: separator tanks, two-phase supply tanks,
distillation columns, connection pipes, valves and
instrumentation.
[0046] Therefore, the present invention allows the aforementioned
problem to be resolved in at least two points: [0047] The number of
pipes forming the connection between equipment leads to an assembly
cost and a significant impact on the overall cost of the
installation. [0048] a. The present invention allows the
interconnection zone to be defined as a central distribution module
between all the modules required for the method. [0049] b. This
separation between the "method functions" (Compression,
Overpressure, Expansion, Cooling, Liquefaction), which are
associated with the designs of each supplier, and the
interconnection enables the possibility of changing suppliers
without necessarily changing the circulation of the fluids. The
connections are adapted to the modules during on-site assembly.
[0050] In order to monitor the evolution that is desired by the
user without having to modify the general design of the path of the
fluids, each module must be able to have an acceptance threshold
for the external stresses.
[0051] The present invention will basically cover the cryogenic
part of the method. It forms the liquefaction area thereof. In
order to limit thermal losses, this part of the method is installed
in an insulating box, called cold box. The temperatures vary
between +20.degree. C. to -196.degree. C. The equipment is
therefore subject to significant mechanical stresses. In order to
reduce the mechanical effects, it is common to distribute the
stresses over the whole of the relevant method line. The solution
implemented in the present invention allows an approach for
managing stresses to be provided by defining the cold box as being
autonomous. The stresses inside the cold box will be managed by
placing a fixed point at the limit of the cold box or by providing
permissible stresses for other parts.
[0052] This installation allows the cold-part modules
(heat-exchange module and separator module) to be aligned together
and allows the hot part (compressor module) to be added in line
with or perpendicular to this alignment, thus reducing the ground
footprint and also reducing the lengths of the
interconnections.
[0053] The invention and the various applications thereof will be
better understood from reading the following description and from
studying the accompanying FIGURES.
BRIEF DESCRIPTION OF THE FIGURES
[0054] For a further understanding of the nature and objects for
the present invention, reference should be made to the following
detailed description, taken in conjunction with the accompanying
drawings, in which like elements are given the same or analogous
reference numbers and wherein:
[0055] The FIGURE shows a representation of a schematic diagram of
a liquefaction system according to one embodiment of the
invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0056] FIG. 1 shows a representation of a schematic diagram of a
liquefaction unit according to one embodiment of the invention.
[0057] In FIG. 1, the hydrocarbon fluid liquefaction unit 1
comprises: [0058] at least one cryogenic cold box 2 comprising:
[0059] at least one heat exchanger; [0060] a fixed assembly zone 8
on its outer wall; [0061] a device 3 for the various equipment
required for implementing the cold fluid required for the
liquefaction of a natural gas stream from a hydrocarbon supply
stream; [0062] an interconnection module 4 comprising a pipe holder
means and a set of pipes, control valves, and electricity
connection and instrumentation 5, 6, 7, designed to connect said at
least one cold box 2 to the at least one equipment device 3 for the
cycle for refrigerating and/or separating C6+ type hydrocarbon
elements contained in the natural gas.
[0063] The interconnection module 4 rests on a frame that allows it
to be handled and is connected to the cold box in the vicinity of
said assembly zone.
[0064] Advantageously, the interconnection module comprises one or
more elements selected from among control valves, manual valves,
valve actuators. Thus, the important elements for controlling the
liquefaction assembly are arranged in the interconnection module,
the assembly and the on-site handling of which are simpler and
safer, which facilitates the assembly of these elements and
facilitates access for maintenance. The safety of the unit is
improved. In particular, one or more valves are of the Pressure
Safety Valve (PSV) type. According to a particular embodiment, the
unit comprises one or more pressure safety valves, all of which are
arranged in the interconnection module.
[0065] The feed stream NG can be a stream of natural gas, which can
be pre-treated, in which one or several substances, such as
sulphur, carbon dioxide, water, are reduced, so as to be compatible
with cryogenic temperatures, as is known in the prior art.
[0066] The heat exchangers are known from the prior art and can
have various arrangements of their feed flows and refrigerant
streams.
[0067] When the flow of liquefied, or at least partially liquefied,
hydrocarbons is liquefied natural gas (LNG), the temperature can be
approximately -150.degree. C. to -160.degree. C.
[0068] The liquefaction of the feed stream NG is carried out by
virtue of a fluid or an expanded cooling nitrogen current in one or
more coolant circuits for pre-cooling the feed stream NG.
[0069] A heat exchange module comprises walls for thermally
insulating the heat exchanger from the outside and comprises a
framework allowing the heat exchange module to be transported so
that it can be fixed.
[0070] The framework can be made of stainless steel bars in order
to reduce the effects of thermal diffusion. Furthermore, this
framework can assume the form of a container, thus forming the
edges of a rectangular parallelepiped, also referred to as a right
cuboid. Thus, it is simple to transport. The framework of the heat
exchange module can also comprise means for facilitating
installation.
[0071] An element is understood to be a module, or a compressor, or
an expansion device or a circuit of a module, or a cooler, or a
separator.
[0072] Connections are understood to be a tube or pipe that may or
may not be insulated and that can comprise valves or
restrictors.
[0073] A stream is understood to be one or more fluids, that may be
in the liquid phase or in the gaseous phase or both, circulating
through elements of the system.
[0074] An inlet is understood to be a point at which the fluid
enters, therefore giving the stream a direction of circulation. In
other words, an inlet of a first element is connected downstream of
an outlet of a second element.
[0075] An outlet is understood to mean that the fluid exits an
element and therefore provides a direction of circulation for the
stream. In other words, an outlet of a first element is connected
upstream of an inlet of a second element.
[0076] Connected means connected for transporting a fluid, for
example, an inlet connected to an element implies that a fluid can
transition from the element to the inlet either directly or via
other elements.
[0077] Connected is understood to mean the connection of two
elements (the outlet of one element to an inlet of another element)
for transporting fluid using connections or connected directly to
one another (an outlet directly connected to an inlet of an element
(without pipe)). In other words, there are no other elements
between the two elements.
[0078] Fixed is understood to mean the physical assembly of one
element to another element in order to secure them together.
[0079] An expanded stream is understood to mean the stream
downstream of an expansion circuit and upstream of a
compressor.
[0080] A compressed stream is understood to mean the stream
upstream of an expansion circuit and downstream of a
compressor.
[0081] The liquefied natural gas resulting from the method that is
the subject matter of the present invention subsequently can be,
for example, transferred to a storage or transportation device.
[0082] The method that is the subject matter of the present
invention particularly enables the investment expenditure to be
optimized. Indeed, having a modular system allows several
arrangements of the modules to be proposed and thus allows the
installation research costs, as well as the manufacturing cost, to
be reduced.
[0083] It will be understood that many additional changes in the
details, materials, steps and arrangement of parts, which have been
herein described in order to explain the nature of the invention,
may be made by those skilled in the art within the principle and
scope of the invention as expressed in the appended claims. Thus;
the present invention is not intended to be limited to the specific
embodiments in the examples given above.
* * * * *