Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
  • F04D27/02—Surge control
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
  • F04D27/02—Surge control
  • F04D27/0261—Surge control by varying driving speed
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D7/00—Pumps adapted for handling specific fluids, e.g. by selection of specific materials for pumps or pump parts
  • F04D7/02—Pumps adapted for handling specific fluids, e.g. by selection of specific materials for pumps or pump parts of centrifugal type
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D13/00—Pumping installations or systems
  • F04D13/02—Units comprising pumps and their driving means
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D25/00—Pumping installations or systems
  • F04D25/02—Units comprising pumps and their driving means
  • F04D25/028—Units comprising pumps and their driving means the driving means being a planetary gear
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D25/00—Pumping installations or systems
  • F04D25/16—Combinations of two or more pumps ; Producing two or more separate gas flows
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
  • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
  • Y02B30/70—Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Definitions

• Embodiments of the subject matter disclosed herein generally relate to a compressor system for natural gas, a method of compressing natural gas and a plant using such a compressor and/or method.
• process gas This happens, for example, in downstream plants wherein the gas comes typically from a pipeline or from another plant (so called "process gas").
• a traditional centrifugal compressor TCC is connected to the output of a traditional parallel-axes gearbox PAGB that is connected to the output of a traditional driver machine TDR; gearbox PAGB increases the rotation speed from input to output and this is schematically represented by the different number of arcs at its input and at its output.
• Fig. 1 highlights that the axes of the input shaft and the output shaft of the gearbox are parallel and at a distance from each other.
• a traditional electric power generator TEPG is connected to the output of a traditional epicyclic gearbox TEGB that is connected to the output of a traditional turbine TTB; gearbox TEGB decreases the rotation speed from input to output and this is schematically represented by the different number of arcs at its input and at its output; Fig. 2 highlights that the axes of the input shaft and the output shaft of the gearbox are coincident.
• a first aspect of the present invention is a compressor system for natural gas.
• a compressor system for natural gas comprises:
• an epicyclic gearbox comprising an input rotary member and an output rotary member, and having a gear ratio greater than one thus increasing the rotation speed from input to output, and
• centrifugal compressor for compressing natural gas comprising an input rotary member
• the output rotary member of said driver machine is coupled to the input rotary member of said epicyclic gearbox, and the output rotary member of said epicyclic gearbox is coupled to the input rotary member of said centrifugal compressor.
• Said epicyclic gearbox may be multi-stage and preferably two-stage.
• Said epicyclic gearbox may comprise at least two (preferably at least three) intermediate shafts transmitting rotation from said input rotary member to said output rotary member, and integrating or mounting one toothed member or two toothed members of different diameters.
• the axes of said at least two intermediate shafts may be arranged to rotate around the axis of the input rotary member of the epicyclic gearbox.
• Said driver machine may be an electric motor.
• Said driver machine may be a gas turbine.
• Said driver machine may be a steam turbine.
• Said gearbox may be mounted on the driver machine.
• Said gearbox may be mounted on foot.
• Said gearbox may be mounted both on the driver machine and on foot.
• the compressor system may comprise further a single baseplate; in this case, said driver machine and said centrifugal compressor are mounted on said single baseplate.
• Said centrifugal compressor may have a rated power in the range from 2 MW to 40
• Said driver machine may comprise two output rotary members; in this case, the compressor system comprises an epicyclic gearbox and a centrifugal compressor for each of said two output rotary members.
• the compressor system may comprise at least one centrifugal compressor in addition to the one already considered; different arrangements are possible.
• said centrifugal compressor may comprise an output rotary member; in this case, the compressor system may comprise further:
• the output rotary member of said centrifugal compressor is coupled to the input rotary member of said another gearbox, and the output rotary member of said another gearbox is coupled to the input rotary member of said another centrifugal compressor.
• another centrifugal compressor is coupled between said driver machine and said epicyclic gearbox.
• the compressor system may comprise further a variable-speed drive system coupled to said driver machine and arranged to vary the rotation speed of said centrifugal compressor.
• a second aspect of the present invention is a method of compressing natural gas.
• a method of compressing natural gas through a centrifugal compressor provides that said centrifugal compressor is driven by a driver machine through an epicyclic gearbox having a gear ratio greater then one.
• the gear ratio of said gearbox may be in the range from 5 to 20.
• Said centrifugal compressor may be operated at a maximum rotation speed in the range from 14000 rpm to 28000 rpm.
• Said centrifugal compressor may be operated at a pressure ratio in the range from 1.5 to 40.
• Said centrifugal compressor may be operated so to provide an maximum output gas pressure in the range from 30 bar to 600 bar.
• Said centrifugal compressor may be operated so to treat a maximum gas flow in the range from 1500 m3/hr to 100000 m3/hr.
• said output rotary member may be used for driving two or more centrifugal compressors at different rotation speeds.
• a third aspect of the present invention is a plant, i.e. an upstream or a downstream plant.
• a plant comprises a compressor system for gas and this compressor system comprises:
• an epicyclic gearbox comprising an input rotary member and an output rotary member, and having a gear ratio greater than one thus increasing the rotation speed from input to output, and
• centrifugal compressor for compressing gas comprising an input rotary member
• the plant may be of the upstream type, in particular of the offshore upstream type.
• the plant may be of the downstream type.
• Said compressor system may comprise one or more of the technical features set out above.
• Fig. 1 shows schematically a prior art solution for compressing natural gas using a parallel-axes gearbox
• Fig. 2 shows schematically a prior art solution for generating electric power using an epicyclic gearbox
• FIG. 3 shows schematically the principle of the compressor systems disclosed herein
• Fig. 4 shows schematically a first embodiment of a compressor system
• Fig. 5 shows schematically a second embodiment of a compressor system
• Fig. 6 shows schematically a third embodiment of a compressor system
• Fig. 7 shows a schematic side view of a fourth embodiment of a compressor system
• Fig. 8 shows a schematic side view of a fifth embodiment of a compressor system
• Fig. 9 shows a schematic side view of a sixth embodiment of a compressor system
• Fig. 10 shows schematically a seventh embodiment of a compressor system
• FIG. 11 shows schematically a eighth embodiment of a compressor system
• Fig. 12 shows schematically a ninth embodiment of a compressor system
• Fig. 13 shows a graph corresponding to a reasonable limit for using parallel-axes gearboxes in combination with gas turbines
• Fig. 14 shows two graphs corresponding to a reasonable limit for using respectively parallel-axes gearboxes and epicyclic gearboxes in combination with electric motors
• Fig. 15 shows a conceptual flowchart of a method for compressing natural gas
• Fig. 16 shows schematically an offshore platform.
• FIG. 3 shows schematically the principle of the compressor systems disclosed herein. This compressor system comprises:
• Driver machine DR comprises a output rotary member DO;
• the epicyclic gearbox EGB comprises an input rotary member GI and an output rotary member GO;
• the centrifugal compressor CC comprises an input rotary member CI.
• the output rotary member DO of the driver machine DR is coupled to the input rotary member GI of the epicyclic gearbox EGB; the output rotary member GO of the epicyclic gearbox EGB is coupled to the input rotary member CI of the centrifugal compressor CC.
• the gear ratio of the epicyclic gearbox EGB is greater than one (typically much greater than one) thus increasing the rotation speed from input to output; this is schematically represented by the different number of arcs at its input, i.e. the member GI, and at its output, i.e. the member GO; specifically, next to the input rotary member GI there is one arc, meaning low rotation speed, and next to the output rotary member GO there are three arcs, meaning high rotation speed.
• centrifugal compressors to be considered for the present patent application in the field of "Oil & Gas", such as those labeled CC, CC1, CC2, CC3, CCA, CCB, CCC in the figures, have typically a rated power in the range from 2 MW to 40 MW.
• the centrifugal compressor rotates at high rotation speed; this is achieved by an epicyclic gearbox with a (relatively) high gear ratio.
• the gear ratio of the epicyclic gearbox is in the range from 5 to 20.
• multi-stage epicyclic gearing may be used.
• Two-stage epicyclic gearing may be a good compromise in terms of radial size, axial size, weight and gear ratio of the gearbox.
• the epicyclic gearbox comprises at least two intermediate shafts transmitting rotation from the input rotary member to the output rotary member of the gearbox; each of these intermediate shafts may integrate or mount two toothed members of different diameters located at opposite sides of the intermediate shaft so that gear ratio is increased in a limited space; these intermediate shafts may be arranged to rotate around the axis of the input rotary member of the epicyclic gearbox; advantageously, three or five intermediate shafts, symmetrically located around the input rotary member, are used.
• the solution of gearbox just described may be considered a specific type of two-stage epicyclic gearbox, the two stages being integrated in a single arrangement, and is called "compound gearing".
• an electric motor EM is used as a driver machine; using electric motor for compressing natural gas is typical of upstream applications particularly for offshore platforms.
• the compressor system of Fig. 4 comprises the electric motor EM, an epicyclic gearbox EGB1 and a centrifugal compressor CC1 connected in train configuration.
• a gas turbine GT is used as a driver machine.
• the compressor system of Fig. 5 comprises the gas turbine GT, an epicyclic gearbox EGB2 and a centrifugal compressor CC2 connected in train configuration.
• a steam turbine ST is used as a driver machine.
• the compressor system of Fig. 6 comprises the steam turbine ST, an epicyclic gearbox EGB3 and a centrifugal compressor CC3 connected in train configuration.
• Fig. 7 and Fig. 8 and Fig. 9 emphasizes the construction of the compressor system even if in a very schematic way. These figures do not specify the kind of driver machine used, and they show simply a driver machine DR, an epicyclic gearbox EGB and a centrifugal compressor CC connected in train configuration.
• Fig. 7 and Fig. 8 and Fig. 9 comprises a single baseplate BP and provide that the driver machine DR and the centrifugal compressor CC are mounted on the baseplate BP.
• the epicyclic gearbox EGB is mounted only on the baseplate BP.
• the epicyclic gearbox EGB is mounted partially on the baseplate BP and partially on the driver machine DR.
• Fig. 7 and Fig. 8 and Fig. 9 mounting directly the epicyclic gearbox on the driver machine (typically on an electric motor) leads to a very compact arrangement, i.e. with a small footprint.
• a double mounting may be a compromise between size of the footprint and mechanical complication of the design of the flanges of the driver machine and the gearbox.
• the choice of the mounting of the epicyclic gearbox is influenced by many factors. Mounting of the gearbox directly on the driver machine allows to save substantial (longitudinal) space, particularly in terms of footprint of the compressor system.
• Other embodiments of the compressor system comprise a number of machines higher than three connected in train configuration as shown for example in Fig. 10, Fig. 11, Fig. 12.
• the driver machine DR comprises two output rotary members, in particular on opposite sides, and there is an epicyclic gearbox (EGBA and EGBB) and a centrifugal compressor (CCA and CCB) for each of the two output rotary members; this may be considered a double-train configuration.
• the compressor system comprises, in addition to the centrifugal compressor CC, another centrifugal compressor CCC; in this case, the compressor CC has an output rotary member (not shown in the figure).
• Another gearbox GB is advantageously provided so that the two compressors CC and CCC may rotate at different rotation speeds.
• the mechanical connection is a single-train configuration; the rotary members of the machines are not shown in the figure.
• the output rotary member of the driver machine DR is connected to the input rotary member of the epicyclic gearbox EGB, the output rotary member of the epicyclic gearbox EGB is connected to the input rotary member of the compressor CC, the output rotary member of the compressor CC is connected to the input rotary member of the gearbox GB; the output rotary member of the gearbox GB is connected to the input rotary member of the compressor CCC. Comparing Fig. 11 with Fig. 1, one can realize that other machines are mechanically connected downstream to compressor CC, and as part of the same train.
• the compressor system comprises, in addition to the centrifugal compressor CC, another centrifugal compressor CCC.
• Another gearbox GB might also be provided.
• the mechanical connection is a single-train configuration; the rotary members of the machines are not shown in the figure.
• the output rotary member of the driver machine DR is connected to the input rotary member of the gearbox GB
• the output rotary member of the gearbox GB is connected to the input rotary member of the compressor CCC
• the output rotary member of the compressor CCC is connected to the input rotary member of the epicyclic gearbox EGB
• the output rotary member of the epicyclic gearbox EGB is connected to the input rotary member of the compressor CC. Comparing Fig. 12 with Fig. 1, one can realize that other machines are mechanically connected between the epicyclic gearbox EGB and the driver machine DR, and as part of the same train.
• the fluid connection in the embodiment of Fig. 12 provides that the gas compressed by compressor CCC is further compressed by compressor CC.
• the rotation speed of compressor CC is much higher than the rotation speed of compressor CCC due to the presence of the epicyclic gearbox EGB; therefore, gearbox GB may also be omitted or, if present (as in Fig. 12), gearbox GB does not need to be an epicyclic gearbox (having a high gear ratio), although it might be.
• VSD variable-speed drive
• a reliable four-poles AC induction electric motor operating at a frequency of 50 Hz may be combined with a reliable VSD system able to vary the frequency from 0 Hz up to 75 Hz; this result in a rotation speed from 0 rpm to 2250 rpm.
• the graph of Fig. 13, labeled PAGB, has been derived by the Inventors and corresponds to a reasonable limit for using parallel-axes gearboxes in combination with gas turbines; this graph assumes a rotation speed of the gas turbine acting as a driver machine of about 6000 rpm; above this limit, parallel-axes gearboxes can not be used and epicyclic gearboxes have to be contemplated.
• a similar graph may be provided for steam turbines.
• the graphs of Fig. 14, labeled PAGB and EGB, have been derived by the Inventors and correspond to a reasonable limit for using respectively parallel-axes gearboxes and epicyclic gearboxes in combination with electric motors; these graphs assume a rotation speed of the electric motor acting as a driver machine of about 1500 rpm (50 Hz operation); very similar graphs may be provided for a rotation speed of about 1800 rpm (60 Hz operation); the best area of application (according to the current technologies) of the combination of a four-poles AC induction electric motor and an epicyclic gearbox is comprised between these two graphs; it is to be considered that four-poles AC induction electric motors are certified to be used for very high power applications (for example 2-40 MW) even in environments with risks of explosions due to a specific gas mixture being compressed.
• Fig. 14 refers to use of four-poles motors, the present invention does not exclude the use of two-poles motors.
• Fig. 14 refers to the compound epicyclic gearboxes (i.e. having a gear ratio greater than about 10 or 11), the present invention does not exclude the use of "simple" (i.e. not compound) epicyclic gearboxes when the required gear ratio is lower (for example lower than 10 or 11).
• the compression of gas in the above described embodiments is carried out, at least partially, by means of a centrifugal compressor driven by a driver machine through an epicyclic gearbox having a gear ratio greater then one.
• a centrifugal compressor CC is arranged (step 1610) according to an appropriate design and/or choice
• a driver machine DR is arranged (step 1620) according to an appropriate design and/or choice
• an epicyclic gearbox EGB is arranged (step 1630) according to an appropriate design and/or choice; by rotating the driver machine DR (step 1640) also the centrifugal compressor CC is rotated by means of the epicyclic gearbox EGB; clearly, the gas is provided to the inlet of the centrifugal compressor CC before starting the driver machine DR.
• the epicyclic gearbox is used for reaching a high rotation speed of the compressor; therefore, preferably, the gear ratio of said epicyclic gearbox is in the range from 5 to 20, depending on the application; the epicyclic gearbox is designed accordingly.
• the centrifugal compressor is operated at a maximum rotation speed in the range from 14000 rpm to 28000 rpm, depending on the application; with present technologies, the upper limit is chosen at about 22000 rpm; the centrifugal compressor is designed accordingly.
• a high rotation speed allows to use more compact and more efficient centrifugal compressors.
• the centrifugal compressor is operated at a pressure ratio in the range from 1.5 to 40, depending on the application.
• the mixture of the gas influence the choice of the pressure ratio: for example, if a natural gas is rich of hydrogen, the lower part of the above mentioned range is preferable due to the risk of explosions.
• the centrifugal compressor is operated so to provide an maximum output gas pressure in the range from 30 bar to 600 bar, depending on the application.
• the centrifugal compressor is operated so to treat a maximum gas flow in the range from 1500 m3/hr to 100000 m3/hr, depending on the application.
• Step 1640 provides to rotate the driver machine of the compressor system and consequently any centrifugal compressor of the compressor system connected or coupled thereto.
• the rotation speed is often constant during stable operation, i.e. regime.
• centrifugal compressors there are more than one centrifugal compressors and the method provides to drive by means of the same driver machine two or more centrifugal compressors at different rotation speeds. This is useful for example when driving two cascaded compression stages.
• FIG. 16 shows an offshore platform OP comprising a compressor system CS feeding compressed natural gas to a pipeline PL; this is an example of an "upstream” application.
• the compressor system CS may be used at an offshore platform to produce compressed gas, to be injected into a well.
• An particular example of a "downstream" application may be the compression of ammonia.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Structures Of Non-Positive Displacement Pumps (AREA)
• Control Of Positive-Displacement Air Blowers (AREA)
• Separation By Low-Temperature Treatments (AREA)

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Citations (4)

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• 2012
  • 2012-01-27 IT IT000002A patent/ITCO20120002A1/it unknown
• 2013
  • 2013-01-24 WO PCT/EP2013/051384 patent/WO2013110733A1/en active Application Filing
  • 2013-01-24 MX MX2014008601A patent/MX2014008601A/es unknown
  • 2013-01-24 US US14/374,590 patent/US20140377083A1/en not_active Abandoned
  • 2013-01-24 ES ES13701100T patent/ES2895980T3/es active Active
  • 2013-01-24 CN CN201380006745.2A patent/CN104487710A/zh active Pending
  • 2013-01-24 AU AU2013213569A patent/AU2013213569A1/en not_active Abandoned
  • 2013-01-24 CA CA2861960A patent/CA2861960C/en active Active
  • 2013-01-24 KR KR1020147023086A patent/KR102051047B1/ko active Active
  • 2013-01-24 EP EP13701100.3A patent/EP2807379B1/en active Active
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  • 2013-01-24 JP JP2014553724A patent/JP6405241B2/ja active Active
  • 2013-01-24 RU RU2014129396A patent/RU2631578C9/ru active
  • 2013-01-24 BR BR112014017629A patent/BR112014017629B8/pt active IP Right Grant
• 2017
  • 2017-03-17 AU AU2017201857A patent/AU2017201857A1/en not_active Abandoned
• 2019
  • 2019-05-01 AU AU2019203084A patent/AU2019203084B2/en active Active

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