Exxonmobil Upstream Research Company

Exxonmobil Technology and Engineering Company

Christopher G Holt

Todd S Griffith

William L Martin

There is provided a system and method for producing liquefied natural gas (LNG). An exemplary method includes flowing a high-pressure stream of LNG through a first series of liquid turbines. The exemplary method also includes generating electricity by reducing the pressure of the high-pressure stream of LNG to form a low-pressure stream of LNG. The exemplary method additionally includes bypassing any one the liquid turbines that has a failure while continuing to produce electricity from the first series.

Systems and methods for using multiple cryogenic hydraulic turbines

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.

Multi-compressor string with multiple variable speed fluid drives

A compressor starting torque converter method and apparatus for high power rotating equipment strings includes a compressor starting torque converter (CSTC) () and gearing to make the input and output speed conform to the speed and power requirements of the at least one compressor () at the end of the string. The string also includes a prime mover (), either a motor or gas turbine with a starter motor. The CSTC is driven by a prime mover that has been geared down (via) to an appropriate speed for efficient power transfer, followed by a gear increasing unit () to allow the output of the CSTC to be increased to conform to the necessary requirements of a high speed compressor. The gearing can be two separate units with their own housings, or incorporated in a single housing with the CSTC. The CSTC may be a CSTC used in pressurized starts high compressor load strings for LNG refrigeration service.

Growing community of inventors

Montgomery, TX, United States of America

Christopher G Holt