Abstract :
Five years of operations have proved that absorption-refrigeration gas processing plants can be economically and successfully fully automated for unattended operations. The automation system protects plant equipment from damage, prevents undesirable operations, alarms personnel, and signals the cause of the alarm. The plant process is similar to other plants, and thus the instrumentation should be applicable to other plants. Dc 24-volt control systems have proved to be simpler and more flexible than 115-volt ac control circuits. Plant downtime from electric outage can be reduced by use of sequence starting of electric motors rather than five-second time delays. A solid-state relay of voltage divider system, gated transistor, and semiconductor diode are used to actuate controls and alarms. Future systems utilizing computers will require control circuits similar to those presented.
