(30d) An Innovative Control Acheme of a C3/MR Lng Plant

A new approach to control of a LNG plant utilizing a C3/MR process was developed and tested using a proprietary dynamic simulator. The system employs flow ratios to manipulate the refrigeration supply and monitors system constraints to maintain conditions within a safe operational envelope. The set points for the control system are fundamental to the operation of the process and therefore intuitive to the operator. The system enables the operator to independently specify the desired LNG production and the LNG temperature exit the refrigeration unit, i.e. MCHE, to satisfy the facility fuel balances. This paper describes the key control pairings, constraints and process responses to various potential disturbances and set point changes.