Abstract: A method and apparatus is provided for controlling the operation of a reforming furnace used to decompose at least a portion of a feed stream. A byproduct fuel from subsequent process steps, which is a result of decomposition of the feed in the reforming furnace, is used as one fuel source to fire the reforming furnace. A supplemental fuel such as natural gas is used as a supplemental fuel source to fire the furnace. The control system provides a prediction of the heat required to decompose the feed in the furnace. The amount of heat which can be supplied by the byproduct fuel stream is then determined. This amount of heat is subtracted from the total predicted heat required and sufficient supplemental fuel is supplied to make up the difference between the predicted required heat and the heat which can be supplied by the byproduct fuel stream.The control system also monitors the temperature of the effluent flowing from the reforming furnace.

Abstract: In the measurement of a variable process parameter and control of the process in response thereto, a transform of a process parameter measurement signal that can be described as the time derivative of a second order or higher lagged process parameter measurement signal is utilized to provide predictive capability. This transform is combined with the output of a PI controller to the input of which the process parameter measurement signal has been fed, thereby generating a process variable signal that either directly or after passing through another controller is utilized as a process control signal for controlling the process in response to the measured parameter. The system is particularly well adapted to control of a non-self-regulating process.