Quench is commonly used in refrigeration applications as the liquid for quenching is produced by the refrigeration compressor. Simple quench controllers maintain temperature at a given set point using a standard PID loop and are slow to react to fast changes in recycle. This type of control does not account for pressure changes which affect the gas dew point and often have set points that are conservative which leads to excessive quenching.
The CCC Quench controller uses the saturation curve of the refrigerant gas and suction drum pressure to accurately determining a temperature set point. The set point is configured as an offset from the saturation curve as shown below.
Through coordinated control with CCC Antisurge control, the Quench controller will quickly add quench flow in anticipation of temperature increase when the recycle valve opens rapidly. This prevents large swings in suction drum temperature. In addition, the Quench controller will only add quench when the recycle valve is open which prevents liquid build up.
Some of the key features of the CCC Quench control application include: