Abstract: Measurements of process variables associated with a cracking furnace are utilized to calculate the actual maximum tube skin temperature for the cracking furnace. The thus calculated actual maximum tube skin temperature is then utilized to derive a control signal which may be utilized to manipulate the rate at which heat is supplied to the cracking furnace. The accurate prediction of the actual tube skin temperature based on actual process measurements enables the conversion rate for the cracking furnace to be substantially maximized while preventing damage to the cracking tubes.

Abstract: The heat provided to a cracking furnace is manipulated so as to substantially maximize the value of the product stream flowing from the cracking furnace. An analysis of the product stream may be utilized to measure the ratio of a first constituent in the product stream to a second constituent in the product stream (severity equivalent). The severity equivalent required to substantially maximize the value of the product stream may be calculated in response to process operating conditions. The heat supplied to the cracking furnace is manipulated in response to a comparison of the actual severity equivalent to the desired severity equivalent to thereby substantially maximize the value of the product stream.