摘要:
A drive system for liquefied natural gas (LNG) refrigeration compressors in a LNG liquefaction plant. Each of three refrigeration compression strings include refrigeration compressors and a multi-shaft gas turbine capable of non-synchronous operation. The multi-shaft gas turbine is operationally connected to the refrigeration compressors and is configured to drive the one or more refrigeration compressors. The multi-shaft gas turbine uses its inherent speed turndown range to start the one or more refrigeration compressors from rest, bring the one or more refrigeration compressors up to an operating rotational speed, and adjust compressor operating points to maximize efficiency of the one or more refrigeration compressors, without assistance from electrical motors with drive-through capability and variable frequency drives.
摘要:
A method for handling the shutdown of a turbomachine string installed in a plant for the liquefaction of a gaseous product comprising at least two turbomachine strings comprises the steps of detecting the shutdown of a first turbomachine string; promptly increasing the driving torque on a shaft of a second turbomachine string when the shutdown is detected; maintaining the driving torque increase on the shaft of the second turbomachine string until a preset speed of the motor driver is reached or a predetermined period of time expires.
摘要:
A system for removing acid gases from a raw gas stream is provided. The system includes a cryogenic distillation column. The cryogenic distillation column receives a dehydrated and chilled sour gas stream, and separates the sour gas stream into an overhead gas stream comprised primarily of methane, and a bottom acid gas stream comprised primarily of carbon dioxide. The system also includes a series of co-current contactors. The co-current contactors may be placed in series to receive the bottom acid gas stream and recapture any entrained methane gas. Alternatively or in addition, the co-current contactors may be placed in series to receive the overhead gas stream, and sweeten it using a reflux liquid such as methane. In this instance, the sweetened gas is optionally liquefied and delivered for commercial sale, or is used as fuel gas on-site.
摘要:
An arrangement for liquefying natural gas is provided. The arrangement includes a gas turbine unit that includes a gas turbine compressor, a steam turbine unit, a first compressor unit, a shiftable clutch, a heated steam generator for supplying steam to the steam turbine unit, and a second compressor unit. The steam turbine unit and the first compressor unit have a common, rigidly connected first shaft assembly, while the gas turbine unit and the second compressor unit have a common, rigidly connected second shaft assembly. In order to increase economic efficiency, the first shaft assembly and the second shaft assembly are operable to be connected to and disconnected from each other using the clutch. A suitable method for starting said arrangement is also provided.
摘要:
At least one gaseous impurity, for example silane, is removed by absorption from a feed gas stream, for example a gas stream comprising nitrogen and hydrogen, the gaseous impurity being less volatile than the feed gas stream. The absorption is effected by a sub-cooled absorbent at a first cryogenic temperature and a first pressure. The absorbent is typically propane. The absorption may be conducted in a liquid-vapour contact column (130). Absorbent containing impurity may be regenerated in a regeneration vessel 150 and returned to the column (130).
摘要:
Apparatuses and methods are provided for producing liquefied gas, such as liquefied natural gas. In one embodiment, a liquefaction plant may be coupled to a source of unpurified natural gas, such as a natural gas pipeline at a pressure letdown station. A portion of the gas is drawn off and split into a process stream and a cooling stream. The cooling stream may sequentially pass through a compressor and an expander. The process stream may also pass through a compressor. The compressed process stream is cooled, such as by the expanded cooling stream. The cooled, compressed process stream is expanded to liquefy the natural gas. A gas-liquid separator separates the vapor from the liquid natural gas. A portion of the liquid gas may be used for additional cooling. Gas produced within the system may be recompressed for reintroduction into a receiving line.
摘要:
A drive system for a refrigeration compressor such as is used in a natural gas liquefaction plant, allowing the desired compressor speed and maximum turbine efficiency to be maintained throughout varying ambient temperature conditions. A gas turbine is used with an electric starter motor with drive-through capability located on a common drive shaft between the turbine and the compressor. A variable frequency drive (VFD) is connected between the electrical power grid and the electric motor for smooth startups, but also to allow excess turbine mechanical power to be converted to electrical power by the motor operating as a generator, and delivered to the grid at the grid frequency. Pulse width modulation technology may be used to reduce harmonic distortion in the VFD's output. The starter motor also functions as a helper motor when the turbine output is insufficient to drive the compressor at the rotational speed needed to meet throughput requirements.
摘要:
An improved system and methodology for starting up a gas-turbine driven multi-stage compressor. The improvement involves isolating individual compression stages and creating positive pressure in each stage prior to initiating rotation of the compressor/driver system. The isolation of individual compression stages allows the turbine to reach normal operating speeds with substantially no supplemental power from an auxiliary source.
摘要:
Improved methodology for starting up a LNG facility employing a refluxed heavies removal column. The improved methodology involves varying the temperature of the feed to the heavies removal column between start-up and normal operation. This allows a larger amount of the stream produced from the top of the heavies removal column during start-up to be used to more rapidly start up the LNG facility.
摘要:
Improved methodology for starting up a LNG facility employing a refluxed heavies removal column. The improved methodology involves varying the temperature of the feed to the heavies removal column between start-up and normal operation. This allows a larger amount of the stream produced from the top of the heavies removal column during start-up to be used to more rapidly start up the LNG facility.