# US 2009/0260367 A1 · Multi-Compressor String With Multiple Variable Speed Fluid Drives

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- Number: US 2009/0260367 A1
- Document ID: US20090260367A1
- Status: Published application
- Kind: A1
- Application number: 12/085,047
- Filed: 2006-11-08
- Published: 2009-10-22
- Earliest claimed: 2005-12-23
- Assignees: ExxonMobil Upstream Research Company
- Inventors: William L. Martin; Christopher G. Holt
- Web page: https://patentgrep.com/patent/US20090260367A1

## CPC

- F04D 25/06: the pump being electrically driven (F04D25/08 takes precedence)
- F02C 6/06: providing compressed gas (F02C6/10 takes precedence)
- F04D 25/02: Units comprising pumps and their driving means
- F04D 25/04: the pump being fluid-driven {(pumps driven by exhaust gases F02B37/00, F02B39/00; turbochargers F02C6/12)}
- F25J 1/0022: {Hydrocarbons, e.g. natural gas}
- F25J 1/0283: {Gas turbine as the prime mechanical driver}
- F25J 1/0284: {Electrical motor as the prime mechanical driver}
- F25J 1/0287: {including an electrical motor}
- F25J 1/029: {Mechanically coupling of different refrigerant compressors in a cascade refrigeration system to a common driver}
- F25J 1/0294: {Multiple compressor casings/strings in parallel, e.g. split arrangement}
- F25J 1/0298: {Safety aspects and control of the refrigerant compression system, e.g. anti-surge control}
- F25J 2280/10: Control for or during start-up and cooling down of the installation
- Y10T 29/49245: Vane type or other rotary, e.g., fan
- F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02)
- F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00)
- F25J: LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS {OR LIQUEFIED GASEOUS} MIXTURES BY PRESSURE AND COLD TREATMENT {OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE (cryogenic pumps F04B37/08; gas storage vessels, gas holders F17; filing vessels with, or discharging from vessels, compressed, liquefied or solidified gases F17C; refrigeration machines, plants, or systems F25B)}
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

Starter arrangement for high power rotating equipment strings with multiple compressors driven by a single turbine or motor includes multiple variable fluid drive torque converters (CSTCs) to start the compressors in a pressurized start. The string can use a single CSTC for each compressor or a single CSTC for more than one compressor with at least two CSTCs for a given string. The starting procedure is sequential. After the turbine or motor is started and brought up to speed, successive CSTCs are operated from zero to lock-up speed sequentially to start each compressor or group of compressors in turn. In order to cool the working fluid of the CSTCs, a single heat exchanger is provided and the working fluid of each CSTC in turn is circulated through the heat exchanger as they are sequentially started. At lock-up speed, the CSTC is locked up, the working fluid is drained, and the working fluid of the active CSTC is isolated from the heat exchanger and the next succeeding CSTC in the start sequence is in turn, filled with the working fluid and connected to the heat exchanger. At full start, with all compressors operating at full speed, no working fluid is present in the CSTCs, and no working fluid is circulated through the heat exchangers from the locked-up CSTCs. A single heat exchanger may also be used for multiple strings, each having multiple CSTCs for multiple compressors. The starter arrangement is useful in high compressor load strings for LNG refrigeration service.

## Claims

### Claim 1

A compressor starting arrangement for a string of rotating equipment, the string including a prime mover and a plurality of compressors to be driven by the prime mover, the starting arrangement comprising:
a first variable speed fluid drive torque converter interposed in said string after said prime mover and before a first compressor; and
a second variable speed fluid drive torque converter interposed in said string before a second of said compressors,
whereby said first and said second compressors are started by said first and second variable speed fluid drive torque converters.

### Claim 2 (depends on 1)

The compressor starting arrangement according to claim 1, wherein said prime mover is a turbine.

### Claim 3 (depends on 1)

The compressor starting arrangement according to claim 1, wherein said prime mover is a motor.

### Claim 4 (depends on 2)

The compressor starting arrangement according to claim 2, wherein said turbine is a single shaft turbine.

### Claim 5 (depends on 2)

The compressor starting arrangement according to claim 2, further including a starter motor and a hydraulic clutch for initiating operation of said turbine.

### Claim 6 (depends on 2)

The compressor starting arrangement according to claim 2, further including a starter motor and a starter motor variable frequency drive for initiating operation of said turbine

### Claim 7 (depends on 3)

The compressor starting arrangement according to claim 3 further including a starter motor and a starting motor VFD for initiating operation of said motor.

### Claim 8 (depends on 3)

The compressor starting arrangement according to claim 3 further including a starter motor and a hydraulic clutch for initiating operation of said motor.

### Claim 9 (depends on 1)

The compressor starting arrangement according to claim 1, wherein each of said first variable speed fluid drive torque converter and said second variable speed fluid drive torque converter is a compressor starting torque converter that uses a working fluid to transmit power from zero output to a lock-up speed at which point the input speed is synchronized to output speed.

### Claim 10 (depends on 1)

The compressor starting arrangement according to claim 1, wherein said compressors are pressurized at start up.

### Claim 11 (depends on 1)

The compressor starting arrangement according to claim 1, further comprising a third compressor and a fourth compressor.

### Claim 12 (depends on 11)

The compressor starting arrangement according to claim 11, further comprising a third variable speed fluid drive torque converter and a fourth variable speed fluid drive torque converter, wherein each of said first, second, third and fourth torque converters is interposed before each of said first, second, third and fourth compressors, respectively.

### Claim 13 (depends on 12)

The compressor starting arrangement according to claim 12, further comprising a fifth compressor in said string connected directly with one of said first, second, third, or fourth compressors, such that a single torque converter starts one of said compressors and said fifth compressor.

### Claim 14 (depends on 5, 6, 7)

The compressor starting arrangement according to claim 5, 6, 7, or 8, further comprising at least one heat exchanger supplied with an external cooling fluid for cooling said working fluids.

### Claim 15 (depends on 14)

The compressor starting arrangement according to claim 14, wherein the working fluids of said first and second variable speed fluid drive torque converters are transmitted through a single heat exchanger.

### Claim 16 (depends on 15)

The compressor starting arrangement according to claim 15, wherein each of said torque converters is connected to said single heat exchanger by a discharge conduit including a discharge valve.

### Claim 17 (depends on 16)

The compressor starting arrangement according to claim 16, further comprising a supply valve in a supply conduit to each of said torque converters.

### Claim 18 (depends on 16)

The compressor starting arrangement according to claim 16, wherein said discharge conduit for each of said torque converters is connected to a common hot manifold, said hot manifold being connected to said single heat exchanger.

### Claim 19 (depends on 17)

The compressor starting arrangement according to claim 17, wherein said supply conduit for each of said torque converters is connected to a common cold manifold, said cold manifold being connected to said single heat exchanger.

### Claim 20

A heat exchanger system for use with a plurality of variable speed hydraulic torque converters in a rotating equipment power string, said torque converters utilizing a hydraulic working fluid, the system comprising:
a single heat exchanger including an external supply of cooling fluid; and
each of said torque converters including a supply conduit for cooled working fluid, and a discharge conduit for the heated working fluid, said supply conduit and said discharge conduit for each of said torque converters being connected to said single heat exchanger, whereby the working fluid for multiple torque converters can be cooled by a single heat exchanger.

### Claim 21 (depends on 20)

The heat exchanger system according to claim 20, further comprising for each of said plurality of torque converters,
a discharge valve in each said discharge conduits, whereby each of said torque converters may be isolated from said single heat exchanger.

### Claim 22 (depends on 21)

The heat exchanger system according to claim 21, further comprising a supply valve in each of said supply conduits, whereby each of said torque converters can be isolated from said single heat exchanger.

### Claim 23 (depends on 20)

The heat exchanger system according to claim 20, further comprising:
a hot manifold;
said hot manifold being connected to said heat exchanger,
wherein said discharge conduits for each of said plurality of torque converters are connected to said hot manifold.

### Claim 24 (depends on 20)

The heat exchanger system according to claim 20, and further comprising:
a cold manifold;
said cold manifold being connected to receive cooled working fluid from said heat exchanger,
wherein said supply conduits for each of said variable speed torque converters are connected to said cold manifold.

### Claim 25 (depends on 21)

The heat exchanger system according to claim 21, further comprising:
a hot manifold;
said hot manifold being connected to said heat exchanger,
wherein said discharge conduits for each of said plurality of torque converters are connected to said hot manifold.

### Claim 26 (depends on 22)

The heat exchanger system according to claim 22, further comprising:
a cold manifold;
said cold manifold being connected to receive cooled working fluid from said heat exchanger,
wherein said supply conduits for each of said variable speed torque converters are connected to said cold manifold.

### Claim 27 (depends on 20)

The heat exchanger system according to claim 20, further comprising for each of said plurality of torque converters:
a cold manifold, said cold manifold being connected to receive cooled working fluid from said heat exchanger, wherein said supply conduits for each of said variable speed torque converters are connected to said cold manifold;
a hot manifold, said hot manifold being connected to said heat exchanger, wherein said discharge conduits for each of said plurality of torque converters are connected to said hot manifold;
a discharge valve in each said discharge conduits, whereby the working fluid discharged form each of said torque converters can be isolated from said single heat exchanger; and
a supply valve in each of said supply conduits, whereby each of said torque converters can be isolated from the cooled working fluid from said single heat exchanger.

### Claim 28 (depends on 20)

The heat exchanger system according to claim 20, further comprising a pump for circulating working fluid through said single heat exchanger.

### Claim 29 (depends on 20)

The heat exchanger system according to claim 20, wherein said string includes a prime mover and multiple compressors.

### Claim 30 (depends on 20)

The heat exchanger system according to claim 20 wherein said string includes a motor and multiple compressors.

### Claim 31 (depends on 20)

The heat exchanger system according to claim 20, further comprising:
a second string of rotating equipment including a plurality of variable speed fluid torque converters,
wherein each of said torque converters of said second string are connected to said single heat exchanger.

### Claim 32

A method for starting a string of rotating power equipment including a prime mover driving multiple compressors, and multiple variable speed fluid torque converters for starting at least a first of said compressors followed by other torque converters starting other compressors, in succession, said prime mover being connected to a first variable speed fluid drive torque converter, and said first torque converter being connected to said first compressor, and at least a second torque converter being connected to said first compressor and in turn connected to a second of said compressors, each of said torque converters providing an output from zero to full speed, the method comprising:
starting the prime mover and bringing it to full speed;
starting said first compressor by increasing the output speed of said first torque converter to full speed; and
starting said second compressor by increasing the output speed of said at least second torque converter to full speed,
whereby the power necessary to start each compressor is supplied successively and in turn by each torque converter.

### Claim 33 (depends on 32)

The method according to claim 32, further comprising a third and a fourth compressor and third and fourth torque converters, and wherein the method further comprises:
increasing the speed of said third torque converter to full speed and starting said third compressor; and
increasing the speed of said fourth torque converter to full speed to start said fourth compressor.

### Claim 34 (depends on 32)

The method according to claim 32, further comprising a third compressor, and wherein
increasing the output speed of said second torque converter starts said second and third compressors.

### Claim 35 (depends on 32)

The method according to claim 32, wherein each torque converter includes a lock-up mechanism engaged at full speed, whereby all power is transmitted mechanically and an input and output speed is synchronized, and wherein the method includes:
locking up each of the torque converters at full speed successively to enable full power transmission.

### Claim 36 (depends on 32)

The method according to claim 32, wherein said prime mover is a turbine and said string includes a starter motor and a hydraulic clutch or starter variable frequency drive connected to said turbine, wherein starting said turbine includes;
starting said starter motor; and
engaging said hydraulic clutch.

### Claim 37 (depends on 32)

The method according to claim 32 wherein said prime mover is a motor and said string includes a starter motor and a hydraulic clutch or starter variable frequency drive connected to said motor, wherein starting said motor includes; starting said starter motor with said variable frequency drive.

### Claim 38

A method of cooling the working fluid of multiple variable speed hydraulic torque converters in a string of rotating power equipment including a prime mover driving multiple compressors, and multiple variable speed fluid torque converters for starting at least one of said compressors followed by other torque converters starting other compressors, in succession, said prime mover being connected to a first variable speed fluid drive torque converter, and said first torque converter being connected to a first compressor, and at least a second torque converter connected to said first compressor and in turn connected to a second of said compressors, each of said torque converters providing an output from zero to full speed, each of said torque converters including a supply conduit for cooled working fluid, and a discharge conduit for the heated working fluid, said supply conduit and said discharge conduit for each of said torque converters being connected to a single heat exchanger, and including a discharge valve in each of said discharge conduits and a supply valve in each of said supply conduits, wherein the method comprises:
starting the prime mover;
opening the supply and discharge valves of said first torque converter while keeping all other valves to said second torque converter closed to permit the working fluid to flow through said first converter and said single heat exchanger;
starting said first compressor and increasing the speed up to full speed;
closing the supply and discharge valves to said first torque converter;
opening the supply and discharge valves to said second torque converter while keeping all other valves closed to permit the working fluid to flow through said second torque converter and said single heat exchanger;
starting said second compressor and increasing its speed to full speed; and
closing the supply and discharge valves to said second torque converter, whereby each of said torque converters can be successively isolated from said single heat exchanger in turn.

### Claim 39 (depends on 38)

The method according to claim 38, wherein said first and second variable speed hydraulic torque converters have different cooling needs and further comprising: providing a heat exchanger with a capacity to satisfy the greater cooling needs.

### Claim 40 (depends on 38)

The method according to claim 38, wherein the heat exchanger is supplied with working fluid from a hot manifold and discharges working fluid to a cold manifold, and wherein the method further comprises:
supplying working fluid through said discharge valves to said hot manifold, and
supplying fluid through said supply valves from said cold manifold to each torque converter.

### Claim 41 (depends on 38)

The method according to claim 38, further comprising a third and a fourth compressor and third and fourth torque converters, and wherein the method further comprises:
opening the supply and discharge valves to said third torque converter while keeping all other valves closed to permit the working fluid to flow through said third torque converter and said single heat exchanger;
starting said third compressor and increasing the speed up to full speed;
closing the supply and discharge valves to said third torque converter;
opening the supply and discharge valves to said fourth torque converter while keeping all other valves closed to permit the working fluid to flow through said fourth torque converter and said single heat exchanger; and
starting said fourth compressor and increasing its speed to full speed.

### Claim 42 (depends on 38)

The method according to claim 38, wherein a second string of equipment is provided, said second string including a plurality of variable speed fluid torque converters and a plurality of compressors, and wherein the method comprises:
providing the torque converters of said second string with supply and discharge conduits for the working fluid; and
connecting said supply and discharge conduit to said single heat exchanger,
whereby said single heat exchanger is usable by more than one string of equipment.

### Claim 43 (depends on 38)

The method according to claim 38, wherein each torque converter includes a lock-up mechanism, engaged at full speed, whereby all power is transmitted mechanically and the input and output speed is synchronized, the method further comprising:
locking up each of the torque converters at full speed, successively, to enable full power transmission mechanically such that working fluid is no longer required.

### Claim 44 (depends on 38)

The method according to claim 38 wherein said prime mover is a turbine.

### Claim 45 (depends on 44)

The method according to claim 44 comprising a starting package having a starting motor and a starting VFD.

### Claim 46 (depends on 44)

The method according to claim 44 comprising a starting package having a starting motor and a starting hydraulic clutch.

### Claim 47 (depends on 38)

The method according to claim 38 wherein said prime mover is a motor.

### Claim 48 (depends on 47)

The method according to claim 47 comprising a starting package having a starting motor and a starting VFD.

### Claim 49 (depends on 47)

The method according to claim 47 comprising a starting package having a starting motor and a starting VFD.

### Claim 50

A compressor starting arrangement for a string of rotating equipment, the string including a turbine or motor, and a plurality of pressurized compressors to be driven by one of said turbine or motor, the arrangement comprising:
a starter motor and a hydraulic clutch for initiating operation of said one of, a turbine or a motor;
a first variable speed fluid drive torque converter interposed in said string after said one of, a turbine or a motor, and before a first compressor;
a second variable speed fluid drive torque converter interposed in said string before a second compressor;
a third variable speed fluid drive torque converter interposed in said string before a third compressor;
a fourth variable speed fluid drive torque converter interposed in said string before a fourth compressor;
each of said variable speed fluid drive torque converters comprising a compressor starting torque converter that uses a working fluid to transmit power from zero output to a lock-up speed at which point the input speed is synchronized to output speed and a torque converter lock up device is engaged and the power is transmitted mechanically;
a single heat exchanger including an external supply of cooling fluid;
a pump for circulating said working fluid through said heat exchanger;
each of said torque converters including a supply conduit for cooled working fluid, and a discharge conduit for the heated working fluid;
a cold manifold being connected to receive cooled working fluid from said heat exchanger, and wherein said supply conduits for each of said variable speed torque converters are connected to said cold manifold;
a hot manifold being connected to said heat exchanger, and wherein said discharge conduits for each of said plurality of torque converters are connected to said hot manifold;
a discharge valve in each of said discharge conduits, whereby the working fluid discharged form each of said torque converters can be isolated from said single heat exchanger; and
a supply valve in each of said supply conduits, whereby each of said torque converters can be isolated from the cooled working fluid from said single heat exchanger,
whereby said compressors are started by said variable speed fluid drive torque converters successively and in turn, and the working fluid for multiple torque converters is cooled by a single heat exchanger.

### Claim 51

A method for manufacturing liquefied natural gas using rotating power equipment including a prime mover driving multiple compressors, said compressors compressing a refrigerant, said compressed refrigerant being used to cool natural gas to a liquid state, and multiple variable speed fluid torque converters for starting at least a first of said compressors followed by other torque converters starting other compressors, in succession, said prime mover being connected to a first variable speed fluid drive torque converter, and said first torque converter being connected to said first compressor, and at least a second torque converter being connected to said first compressor and in turn connected to a second of said compressors, each of said torque converters providing an output from zero to full speed, said method comprising:
starting the prime mover and bringing it to full speed;
starting said first compressor by increasing the output speed of said first torque converter to full speed; and
starting said second compressor by increasing the output speed of said at least second torque converter to full speed,
whereby the power necessary to start each compressor is supplied successively and in turn by each torque converter.