Note: Descriptions are shown in the official language in which they were submitted.
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MODULARIZATION OF A HYDROCARBON PROCESSING PLANT
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the priority benefit of United States
Patent Application
62/237,838 filed October 6, 2015 entitled MODULARLIZATION OF A HYDROCARBON
PROCESSING PLANT, the entirety of which is incorporated by reference herein.
BACKGROUND
Field of Disclosure
[0002] The disclosure relates generally to the field of hydrocarbon
processing plants. More
specifically, the disclosure relates to the efficient design, construction and
operation of
hydrocarbon processing plants, such as LNG processing plants.
Description of Related Art
[0003] 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.
[0004] In a time when competition for LNG production contracts is
increasing, there is a
tremendous need to enhance the profitability of future LNG projects. To do so,
LNG producers
may identify and optimize the key cost drivers and efficiencies applicable to
each project.
Rendering projects economical in locations with high costs and low on-site
labor productivity
may require minimizing the scope and extent of site labor required to
construct and commission
the LNG plant. Modularization techniques are being employed to tackle this
challenge by
shifting scope from being built on-site to being built in specialized
fabrication yards. However,
for large scale LNG projects the modularization of construction scope can
still result in
significant site integration costs. Accordingly, there is a recognized need in
the plant
construction industry to remove additional work scope from the plant site
compared to other
modularization methods currently deployed by industry.
[0005] Figures 1 and 2 depict a known layout of an LNG producing
facility, which may be
termed an LNG train 10. The LNG train 10 includes multiple processing units
disposed along
a central piperack 12. The processing units are connected to each other and to
any functional
units within the piperack via multiple pipes and conduits that direct utility
streams, feed gas 14
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and resulting products and side-products as desired. In the example shown in
Figure 1, the
LNG train 10 includes an acid gas removal (AGR) unit 16 that removes CO2 and
H2S molecules
from the feed gas 14 down to the very low levels required to prevent freezing
in the downstream
refrigeration and liquefaction units. A dehydration unit 18 removes water
molecules from the
feed gas down to the very low levels required to prevent freezing in the
downstream
refrigeration and liquefaction units. A Heavy Hydrocarbon Capture (HHC) or
heavy
hydrocarbon removal unit 20 removes C6+ molecules from the feed gas below
levels necessary
to prevent freezing in the downstream refrigeration and liquefaction units.
The dehydration
unit 18 and the HHC unit 20 may be separate, or as shown in Figure 1, may be
combined into
a single module. Other processing units, such as a cryogenic heat exchanger
and end-flash gas
equipment 22, refrigeration compressors 24 and 26, and a C3 chiller unit 28,
are also included.
Refrigeration and liquefaction of the feed gas are achieved using any of the
various known
refrigeration circuits. As an example, mechanical refrigeration coolers 30, 32
are included in
or on the piperack 12 and the resulting extracted enthalpy is rejected using
ambient cooled heat
exchangers, such as air fin coolers 34 (Figure 2) arranged in, or preferably
on, the piperack 12.
Mechanical power is delivered by one or more drivers (not shown) to the
refrigeration
compressors 24, 26. The multiple drivers may be gas-fired turbines, electric
motors, or the
like. A refrigerant desuperheater and subcooler unit 36 and a refrigerant
condenser unit 38 are
used to desuperheat, condense, and subcool spent refrigerant (such as propane)
according to
known principles, to reject enthalpy using ambient cooled heat exchangers,
such as air fin
coolers. The LNG train 10 may be further modularized by dividing the piperack
12 into
modules 12a, 12b, 12c, 12d, and 12e. Each of the processing units and the
piperack modules
may be pre-assembled at a fabrication yard or other off-site manufacturing
location, transported
to the operating site of the LNG train, and connected together to construct
the completed LNG
train.
[0006] The LNG train 10 shown in Figure 1 represents known attempts to
modularize gas
processing plant design, and is characterized by installing process units
(such as the AGR unit,
dehydration unit and/or the HHC unit) along the central piperack 12, and
piping connections
between separate units are routed through the central piperack 12. However,
this
modularization strategy results in a significant number of piping connections
at the interfaces
between the process units and the piperack modules. Connecting the piping
connections onsite
is a labor-intensive activity. Furthermore, every line 33 connecting two
process modules, such
as the AGR unit 16 and the dehydration unit 18, must pass through the piperack
to do so, and
there will be a minimum of two site connections at interfaces with each
central piperack
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segment installed individually at site which is traversed by the line.
[0007] Additionally, in ambient air-cooled LNG train designs the air-
cooled heat
exchangers 34 are generally installed in a bank or banks on top of the central
piperack structure.
The size and number of these heat exchangers may establish the length and
width of the central
piperack 12 and, as a result, the overall footprint of the LNG train. This
layout results in a
significant number of labor-intensive large bore piping connections at the
interfaces between
air cooler piperack modules and pipe segments running through the piperack
modules, and
these connections usually are finished at an operating site rather than a
manufacturing site.
[0008] Another attempt to modularize the design of an LNG train uses
small capacity LNG
trains (-2 MTA) and uses a single natural gas treatment module that performs
the functions of
the AGR unit, the dehydration unit, and the HHC unit. However, if a higher
capacity of LNG
is required to be processed, multiple identical modular trains must be used,
which results in the
duplication of module interconnections and associated work scope at the LNG
site. Therefore,
a need exists for a modularized design for a high-capacity hydrocarbons
processing plant, such
as an LNG train, in which the amount of work to assemble modular parts thereof
at an operating
site is minimized.
SUMMARY
[0009] In an aspect, a hydrocarbon processing plant is disclosed. A
piperack structure has
a major axis parallel to the major axis of the train with which it is
associated. A first
multipurpose module, substantially pre-assembled prior to being transported to
an operating
site, has a major axis that is parallel to the major axis of the piperack. The
first multipurpose
module contains: process components that perform a function related to
hydrocarbon
processing or handling; piping systems that connect the process components
directly to a
second, where the second multipurpose module is adjacent the first
multipurpose module, and
wherein at least part of the piping systems are aligned with the major axis of
the piperack
structure; and at least one heat exchanger located in the first multipurpose
module and
operationally connected to process components in the hydrocarbon processing
plant.
[0010] The present disclosure also provides a method of hydrocarbon
processing plant. A
piperack structure has a major axis parallel to the major axis of the train
with which it is
associated. A first multipurpose module, substantially pre-assembled prior to
being transported
to an operating site, has a major axis that is perpendicular or substantially
perpendicular to the
major axis of the piperack. The first multipurpose module contains: process
components that
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perform a function related to hydrocarbon processing or handling; piping
systems that connect
the process components directly to a second module, where the second module is
adjacent the
first multipurpose module, and wherein at least part of the piping systems are
aligned with the
major axis of the piperack structure; and a plurality of heat exchangers
located in the first
multipurpose module and operationally connected to process components located
in the
hydrocarbon processing plant. The plurality of heat exchangers are aligned
with the major axis
of the first multipurpose module.
[0011] The present disclosure further provides a method of constructing a
hydrocarbon
processing plant. A train is provided at an operating site. The train has a
major axis. A
piperack structure is provided at the operating site. The piperack structure
has a major axis
that is parallel to the major axis of the train. A heat exchanger bank is
provided that runs along
the major axis of the train. A first multipurpose module is substantially pre-
assembled at a
manufacturing site that is separate from the operating site. The first
multipurpose module
includes: process components that perform a function related to hydrocarbon
processing or
handling; piping systems; and a plurality of heat exchangers operationally
connected to process
components in the train, wherein the plurality of heat exchangers are aligned
with the major
axis of the first multipurpose module. The first multipurpose module is
transported to the
operating site. The first multipurpose module is operationally connected, at
the operating site,
to the train such that (a) the major axis of the first multipurpose module is
either parallel or
substantially perpendicular to the major axis of the piperack, (b) the piping
systems connect
the process components directly to a second module that is adjacent the first
multipurpose
module, and (c) at least part of the piping systems are aligned with the major
axis of the
piperack structure.
[0012] 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
[0013] 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.
[0014] Figure 1 is a schematic diagram of an LNG train according to known
principles.
[0015] Figure 2 is a top plan view of an LNG train according to known
principles.
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[0016] Figure 3 is a schematic diagram of an LNG train.
[0017] Figure 4 is a schematic diagram of an LNG train.
[0018] Figure 5 is a top plan view of an LNG train.
[0019] Figure 6 is a top plan view of an LNG train.
[0020] Figure 7 is a top plan view of an LNG train.
[0021] Figure 8 is a flowchart of a method according to aspects of the
disclosure.
[0022] 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
[0023] 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.
[0024] At the outset, for ease of reference, certain terms used in this
application and their
meanings as used in this context are set forth. To the extent a term used
herein is not defined
below, it should be given the broadest definition persons in the pertinent art
have given that
term as reflected in at least one printed publication or issued patent.
Further, the present
techniques are not limited by the usage of the terms shown below, as all
equivalents, synonyms,
new developments, and terms or techniques that serve the same or a similar
purpose are
considered to be within the scope of the present claims.
[0025] As one of ordinary skill would appreciate, different persons may
refer to the same
feature or component by different names. This document does not intend to
distinguish
between components or features that differ in name only. The figures are not
necessarily to
scale. Certain features and components herein may be shown exaggerated in
scale or in
schematic form and some details of conventional elements may not be shown in
the interest of
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clarity and conciseness. When referring to the Figures described herein, the
same reference
numerals may be referenced in multiple figures for the sake of simplicity. In
the following
description and in the claims, the terms "including" and "comprising" are used
in an open-
ended fashion, and thus, should be interpreted to mean "including, but not
limited to."
[0026] 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.
[0027] 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 and are considered to be within
the scope of the
disclosure. Nevertheless, an element is "substantially perpendicular" to a
reference element
when the element is oriented at an angle of between 80 degrees and 100 degrees
to the reference
element.
[0028] The term "acid gas" and "sour gas" refers to any gas that
dissolves in water to
produce an acidic solution. Non-limiting examples of acid gases include
hydrogen sulfide
(H2S), carbon dioxide (CO2), or sulfur dioxide (S02), or mixtures thereof
[0029] The term "heat exchanger" refers to a device designed to
efficiently transfer or
"exchange" heat from one matter to another. Exemplary heat exchanger types
include a co-
current or counter-current heat exchanger, an indirect heat exchanger (e.g.
spiral wound heat
exchanger, plate-fin heat exchanger such as a brazed aluminum plate fin type,
shell-and-tube
heat exchanger, etc.), direct contact heat exchanger, or some combination of
these, and so on.
[0030] The "major axis" of an element refers to a line of symmetry
parallel to the
predominant linear dimension of the element. In other words, an element is
longest in a
direction of its major axis than along any other axis perpendicular or
substantially
perpendicular thereto.
[0031] The term "piperack" refers to a structural system that supports
pipes, conduits tubes,
and the like.
[0032] Although the phrases "gas stream," "vapor stream," and "liquid
stream," refer to
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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.
[0033] The disclosure relates to a system and method for the standardized
design and
construction of a hydrocarbon processing plant, such as an LNG train. In an
aspect, a
significant number of connections between modules and/or processing units may
be eliminated
by integrating process equipment and piperack components in multipurpose
modules that are
connected to other distinct abutting modules. Additionally, ambient cooled
heat exchangers,
such as air fin coolers, can be located in the multipurpose modules. This is
in contrast to the
traditional LNG train design where (1) all process units and modules are
arranged around a
central piperack and (2) ambient cooled heat exchangers rejecting heat from
the process units
are located in or on the central piperack.
[0034] Figures 3-7 of the disclosure display various aspects of the
system and method in
comparison with known LNG plant layouts. Figure 3 depicts a hydrocarbon
processing plant,
and specifically depicts an LNG train 300. The LNG train may have a major axis
302. The
LNG train 300 may include multiple processing units disposed along a central
piperack 312.
The central piperack 312 may have a major axis 304. In an aspect, the major
axis 302 of the
LNG train 300 and the major axis 304 of the central piperack 312 are parallel
to each other. In
a further aspect, the major axis 302 and the major axis 304 overlay each
other, or in other
words, are co-incident. The central piperack 312 may be divided into multiple
piperack
modules. The processing units may be connected other processing units, to
adjacent piperack
modules, and/or to any functional units within or co-located with the central
piperack 312, via
multiple pipes and conduits that direct a feed gas stream 314 and resulting
products and side-
products as desired. In an aspect shown in Figure 3, the processing units may
include a
dehydration unit 318, which may be included to remove water molecules from the
feed gas
down to the very low levels required to prevent freezing in the downstream
refrigeration and
liquefaction units. Another processing unit may be a heavy hydrocarbon capture
(HHC) or
heavy hydrocarbon removal unit 320, which may be included to remove C6+
molecules from
the feed gas below levels necessary to prevent freezing in the downstream
refrigeration and
liquefaction units. The dehydration unit 318 and the HHC unit 320 may be
separate, or as
shown in Figure 3, may be combined into a single module. Other processing
units, such as a
cryogenic heat exchanger and end-flash gas equipment 322, refrigeration
compressors 324 and
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326, and a C3 chiller unit 328, may also be included. Refrigeration and
liquefaction of the feed
gas are achieved using any of the various known refrigeration circuits. As an
example,
mechanical refrigeration coolers 330, 332 are included in or on the piperack
312 and the
resulting extracted enthalpy is rejected using ambient cooled heat exchangers,
such as air fin
coolers arranged in, or preferably on, the piperack 312. Mechanical power is
delivered by one
or more drivers (not shown) to the refrigeration compressors 324, 326. The
multiple drivers
may be gas-fired turbines, electric motors, or the like. A refrigerant
desuperheater and
subcooler unit 336 and a refrigerant condenser unit (not shown) are used to
desuperheat,
condense, and subcool spent refrigerant (such as propane) according to known
principles, to
reject enthalpy using ambient cooled heat exchangers, such as air fin coolers.
Each of the
processing units and the piperack modules may be pre-assembled at
manufacturing site such
as a fabrication yard or other off-site location, transported to an assembly
site such as the
expected operating site or location of the LNG train, and connected together
to construct the
completed LNG train.
[0035] The LNG train 300 may also include acid gas removal (AGR) equipment
or
components that remove CO2 and H2S molecules from the feed gas 314 down to the
very low
levels required to prevent freezing in the downstream refrigeration and
liquefaction units. As
shown in Figure 3, the AGR equipment or components are modularized to form a
multipurpose
AGR module 316. The AGR module is termed 'multipurpose' because it includes
process
components that perform the AGR function, piping systems that connect the AGR
components
to other multipurpose modules or to the central piperack, and at least one
heat exchanger
(preferably an ambient cooled heat exchanger) operationally connected to the
AGR
components or to other processing components elsewhere in the LNG train 300.
Other
processing units may also be defined as multipurpose processing units as
desired. The
multipurpose AGR module 316 is located at the front end of the LNG train 300,
and piping
connections from the remainder of the central piperack 312 to the multipurpose
AGR module
316 and/or to other processing units may be routed through the multipurpose
AGR module 316.
All ambient cooled heat exchangers used by the AGR process, such as a lean
amine cooler (not
shown) and/or a regenerator overhead cooler (not shown) are located in or on
the multipurpose
AGR module 316. This configuration eliminates multiple connections between the
multipurpose AGR module 316 and the central piperack 312 that were required in
the
conventional layout configuration described and shown in Figures 1 and 2. For
example,
installation site labor cost savings are realized by eliminating four or more
large bore
connections (greater than 12 inches or about 0.3 meters) and ten or more small
bore connections
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(less than 12 inches or about 0.3 meters). As another example, the AGR module
may comprise
an amine solvent unit used for the removal of acid gas from the natural gas
stream. As a further
example, amine-based AGR may use two large columns: an amine absorber and an
amine
regenerator. These two columns may be included in the multipurpose AGR module
316.
Alternatively, these two columns may be erected and connected to the
multipurpose AGR
module 316 at the operating site.
[0036] Another aspect is shown in the LNG train 400 of Figure 4. The LNG
train may
have a major axis 402. The LNG train 400 may include multiple processing units
disposed
along a central piperack 412. The central piperack 412 may have a major axis
404. In an
aspect, the major axis 402 of the LNG train 400 and the major axis 404 of the
central piperack
412 are parallel to each other. In a further aspect, the major axis 402 and
the major axis 404
overlay each other or are co-incident with each other. The central piperack
412 may be divided
into multiple piperack modules. The processing units may be connected to each
other and to
any functional units within or co-located with the central piperack 412 via
multiple pipes and
conduits that direct a feed gas stream and resulting products and side-
products as desired. In
an aspect shown in Figure 4, the processing units may include an AGR
processing module 416,
which may be an multipurpose AGR processing module as previously described.
The AGR
processing module 416 is disposed along the central piperack 412 but separate
from the major
axis 404 of the central piperack 412. Other processing units or modules may be
included as
previously described, such as: a cryogenic heat exchanger and end-flash gas
equipment 422;
refrigeration compressors 424 and 426; a C3 chiller unit 428; mechanical
refrigeration coolers
430, 432; a refrigerant desuperheater and subcooler unit 436; and a
refrigerant condenser unit
438.
[0037] Equipment that performs the dehydration process may be modularized
and
integrated with a piperack section or module to form a multipurpose
dehydration/HHC module
418. The multipurpose dehydration/HHC module 418 may be located at the
appropriate
location for LNG processing, which as shown in Figure 4 is toward the front
end 406 of the
LNG train 400 and downstream of the multipurpose AGR module 416. For the
purpose of
removing heavy hydrocarbons from the natural gas stream, the multipurpose
dehydration/HI-IC
module 418 may include one or more of a scrub column, a molecular sieve
adsorption bed, and
a Joule-Thompson assembly. The multipurpose dehydration/HHC module 418 may
include a
molecular sieve adsorption bed for dehydration, which may be located in a
sequence that is
parallel to the central piperack. In another aspect, the molecular sieve
adsorption bed
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associated with dehydration is located in the same multipurpose module with
the molecular
sieve adsorption bed associated with extraction of heavy hydrocarbons (i.e.,
C6+ components)
from a natural gas stream, and wherein both molecular sieve adsorption beds
are located in a
sequence that is parallel to the piperack assembly.
[0038] Piping connections from the piperack 412 and the multipurpose AGR
module 416
connecting to other downstream processing units or piperack modules in the LNG
train are
routed through the multipurpose dehydration/HHC module 418. All or
substantially all
ambient cooled heat exchangers used in the dehydration and HHC processes, such
as a
regeneration gas cooler, are located on or in the multipurpose dehydration/HHC
module. This
solution eliminates multiple connections between the multipurpose
dehydration/HHC module
418 and the piperack 412 that were required in known LNG layout configurations
as previously
described.
[0039] Figure 5 shows other aspects of the disclosed invention. LNG train
500 includes a
central piperack 512 that has a major axis 504 that overlays or is co-incident
with the major
axis 502 of the LNG train 500. The central piperack 512 comprises piperack
modules 512a,
512b, 512c, 512d, and 512e. Each of the piperack modules 512a-e may be
manufactured at a
manufacturing site and transported to an assembly site, which may be the
operating location of
the LNG train, to be assembled together. Other processing units of LNG train
500 may include
a cryogenic heat exchanger and end-flash gas equipment 522, refrigeration
compressors 524
and 526, and a C3 chiller unit 528, all as previously described herein. The
other processing
units previously described (i.e., mechanical refrigeration coolers,
refrigerant desuperheater and
subcooler unit, and refrigerant condenser unit) form part of the LNG train 500
along its major
axis 502. A plurality of heat exchanger units 534, which may be termed a heat
exchanger bank,
are disposed in or on the central piperack 512 along its major axis 504. The
heat exchanger
units 534 may be ambient heat exchanger units, and may be ambient air fin heat
exchanger
units. As shown in Figure 5, the heat exchanger units 534 may be arrayed in
two parallel lines
534a, 534b.
[0040] A multipurpose AGR module 516 is disposed along the major axis 502
of the LNG
train 500. The multipurpose AGR module 516 has a major axis 506. In an aspect,
the major
axis 506 is parallel to, and/or co-incident with, the major axes 502, 504. The
multipurpose
AGR module 516 includes heat exchanger units 540 that provide some or all of
the required
cooling for the AGR equipment or components thereon. The heat exchanger units
540 may be
ambient heat exchanger units, and may be ambient air fin heat exchanger units.
While the heat
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exchanger units 540 may be disposed along the major axis 506 and therefore are
at least parallel
to the disposition of the heat exchanger units 534 associated with the central
piperack 512, the
heat exchanger units may be designed and configured to provide a heat exchange
function only
for the equipment or components in the multipurpose AGR module 516, and
therefore may not
be considered to be part of the heat exchanger units 534, which are designed
to provide a heat
exchange function for other processing units of the LNG train 500.
[0041] A multipurpose dehydration/HHC module 518 is also disposed along
the major axis
502 of the LNG train 500. The multipurpose dehydration/HHC module 518 has a
major axis
508. The multipurpose dehydration/HHC module 518 includes ambient air fin heat
exchangers
542 that provide some or all of the required cooling for the dehydration/HHC
equipment or
components thereon. The heat exchanger units 542 may be ambient heat exchanger
units, and
may be ambient air fin heat exchanger units. While the heat exchanger units
542 may be
disposed along the major axis 508 and therefore are at least parallel to the
disposition of the
heat exchanger units 534 associated with the central piperack 512, the heat
exchanger units 542
may be designed and configured to provide a heat exchange function only for
the equipment
or components in the multipurpose dehydration/HHC module 518, and therefore
may not be
considered to be part of the heat exchanger units 534, which are designed to
provide a heat
exchange function for other processing units of the LNG train 500.
[0042] Another aspect is shown in the LNG train 600 of Figure 6, which is
similar to LNG
train 500. LNG train 600 includes a multipurpose AGR module 616 and a
multipurpose
dehydration/HHC module 618 having major axes 606, 608 parallel but not co-
incident with the
major axis 604 of the central piperack 612. The multipurpose AGR module 616
and/or the
multipurpose dehydration/HHC module 618 may be positioned such that rows of
heat
exchanger units 640, 642 respectively associated therewith are aligned with
one of the parallel
lines 634a, 634b of the heat exchangers 634 associated with the central
piperack 612.
[0043] Another aspect is shown in the LNG train 700, which is similar to
LNG trains 500
and 600. LNG train 700 includes a multipurpose AGR module 716 having a major
axis 706,
and a multipurpose dehydration/HHC module 718 having a major axis 708. The
multipurpose
AGR module 716 is positioned so that its major axis 706 is perpendicular or
substantially
perpendicular to the major axis 704 of the piperack. Rows of heat exchanger
units 740
associated therewith are aligned with major axis 706. The multipurpose
dehydration/HHC
module 718 is positioned so that its major axis 708 is parallel and/or co-
incident with the major
axis 704 of the central piperack 712. The multipurpose dehydration/HHC module
718 may be
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positioned such that rows of heat exchanger units 742 associated therewith are
aligned with
one of the parallel lines 734a, 734b of the heat exchangers 734 associated
with the central
piperack 712.
[0044] In another aspect, the function performed by a multipurpose module
may include
the mechanical refrigeration of the natural gas stream, which may be
accomplished in part by
rejecting heat to an ambient (i.e., to the environment at the operating site)
using one or more
air and/or water- cooled heat exchangers. The mechanical refrigeration may be
accomplished
in part by a refrigerant comprising propane and/or propylene. Alternatively or
additionally, the
mechanical refrigeration may be accomplished in part by a mixed refrigerant
comprising
methane, ethane and/or ethylene, propane and/or propylene, and/or butane.
[0045] The disclosed aspects discuss one or more multipurpose modules
that are assembled
at a manufacturing site that is separate from or distant from the operating
site of a hydrocarbon
processing facility (such as an LNG plant), transported to the operating site,
and connected to
parts of the hydrocarbon processing facility. As discussed herein, it may not
be feasible to
assemble all parts or components of a multipurpose module at a manufacturing
site. According
to disclosed aspects, a multipurpose module may include components built or
assembled on or
adjacent the multipurpose module but transported to the operating site
separate from the
multipurpose module. Such components may be considered to be part of the
multipurpose
module because the components perform part of the function associated with the
remaining
components on the multipurpose module. Additionally, while the disclosed
aspects have been
described as being part of an LNG plant, the aspects may be advantageously
used in the
construction of other hydrocarbon processing plants.
[0046] Another aspect uses refrigerant driver and compressor string
modules that include
the interstage and discharge coolers for refrigerant compressors. The
compressor discharge
streams are cooled directly by air cooled heat exchangers installed on the top
of the
compression string module or by a recirculating or once-through water cooling
system with
heat exchangers installed within the compression modules. This disclosed
aspect can be
deployed with either electric motor, gas turbine or steam compressor drivers.
The benefits of
the disclosed aspects include a decrease in the size of the central piperack
and the footprint of
the LNG train, a decrease in the number of process streams (e.g. compressor
discharge streams)
requiring site piping connections to the central piperack, and the cost
savings associated with
these benefits. Additional benefits are realized by schedule and logistics
synergies associated
with the reconfigured layout and the opportunity to conduct more pre-
commissioning of the
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refrigerant driver and compressor systems in the fabrication yard. In one
example, it is
estimated that modularizing the compressors as disclosed herein eliminates
approximately 20%
of the required man-hours for construction of a single LNG train. With LNG
processing plants
having three or more LNG trains, the savings in construction costs can be
significant.
Furthermore, locating air fin coolers on top of the compressor modules has the
potential of
removing two piperack modules and may eliminate as much as 60 large-bore
connections that
would otherwise be required to be completed at the assembly site.
Additionally, approximately
25% of the high reliability welds (i.e., "golden welds") are eliminated as
well. The cost savings
associated with the reduced number of connections and welds is anticipated to
be significant.
[0047] Figure 8 depicts a method 800 of constructing a hydrocarbon
processing plant
according to aspects disclosed herein. At step 802 a train is provided at an
operating site. The
train has a major axis. At step 804 a piperack structure is provided at the
operating site. The
piperack structure has a major axis that is parallel to the major axis of the
train. At step 806 a
heat exchanger bank is provided that runs along the major axis of the train.
At step 808 a first
multipurpose module is substantially pre-assembled at a manufacturing site
that is separate
from the operating site. The first multipurpose module includes: process
components that
perform a function related to hydrocarbon processing or handling; piping
systems; and a
plurality of heat exchangers operationally connected to process components
located therein,
wherein the plurality of heat exchangers are aligned with the major axis of
the first
multipurpose module. At step 810 the first multipurpose module is transported
to the operating
site. At step 812 the first multipurpose module is operationally connected, at
the operating site,
to the train such that (a) the major axis of the first multipurpose module is
either parallel or
substantially perpendicular to the major axis of the piperack, (b) the piping
systems connect
the process components directly to a second module that is adjacent the first
multipurpose
module, and (c) at least part of the piping systems are aligned with the major
axis of the
piperack structure.
[0048] The steps depicted in Figure 8 are provided for illustrative
purposes only and a
particular step may not be required to perform the inventive methodology.
Moreover, Figure
8 may not illustrate all the steps that may be performed. The claims, and only
the claims, define
the inventive system and methodology.
[0049] 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
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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 CO2, for example the sequestration
of CO2, 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/or 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 LNG plant or other processing plant as described herein. Other
hydrocarbon
extraction activities and, more generally, other hydrocarbon management
activities, may be
performed according to known principles.
[0050] It should be understood that the 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.
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