Air Products and Chemicals, Inc.

Yu-Nan Liu

Charles L Newton

David Anthony Zagnoli

Glenn E Kinard

James W Pervier

Glenn Eugene Kinard

Charles Leo Newton

Timothy Truong

A method for controlling the operation of a liquefied natural gas (LNG) process which utilizes gas turbine-driven refrigeration compressors is disclosed. A feedforward control system compensates for the effects of changes in ambient air temperature on the plant operating efficiency by periodically predicting a new temperature and resetting the set points of key feedback controllers in anticipation of this new temperature, thereby optimizing the operation of the plant and minimizing the specific fuel consumption at a given LNG production rate.

Gas liquefaction process control system

A closed loop single component, e.g. propane or Freon refrigerant, refrigeration cycle is added to a single or dual mixed refrigerant natural gas liquefaction process to precool the natural gas prior to adsorptive drying. By means of pressure control, the single component refrigerant temperature can be accurately controlled to ensure against hydrate formation in the natural gas feed and to maximize the precooling of the natural gas feed prior to drying. The addition of the single component refrigeration cycle overcomes the difficulty of controlling the precooling temperature which occurs when cooling by a multicomponent refrigerant, and thus improves plant reliability and minimizes the equipment sizes associated with the drying operation.

Feed gas drier precooling in mixed refrigerant natural gas liquefaction

A process and apparatus is described for liquefying natural gas using two closed cycle, multicomponent refrigerants wherein a low level refrigerant cools and liquefies the gas by indirect heat exchange and a high level refrigerant cools and partially liquefies the low level refrigerant by indirect multistage heat exchange. The high level refrigerant is phase separated in order to use lighter refrigerant components to perform the final lowest level of refrigeration while the liquid phase of the separation is split and then expanded for refrigeration duty in order to avoid multiple flash separations wherein heavier components are used to provide the lower levels of refrigeration.

Dual mixed refrigerant natural gas liquefaction

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Whitehall, PA, United States of America

Yu-Nan Liu