| cycling [`sīk·liŋ] CHEMICAL ENGINEERING A series of operations in petroleum refining or natural-gas processing in which the steps are repeated periodically in the same sequence. CONTROL SYSTEMS A periodic change of the controlled variable from one value to another in an automatic control system. PETROLEUM ENGINEERING An operation in which gas flowing from a gas reservoir is passed through a processing plant or separation system, with the gas remaining being returned to the reservoir. Also known as oscillation. |