Laser ultrasonic furnace tube coke monitor. Quarterly technical progress report No. 1, May 1--August 1, 1998

Abstract

The overall aim of the project is to demonstrate the performance and practical use of a laser ultrasonic probe for measuring the thickness of coke deposits located within the high temperature tubes of a thermal cracking furnace. This aim will be met by constructing an optical probe that will be tested using simulated coke deposits that are positioned inside of a bench-scale furnace. Successful development of the optical coke detector will provide industry with the only available method for on-line measurement of coke deposits. The optical coke detector will have numerous uses in the refining and petrochemical sectors including monitoring of visbreakers, hydrotreaters, delayed coking units, vacuum tower heaters, and various other heavy oil heating applications where coke formation is a problem. The coke detector will particularly benefit the olefins industry where high temperature thermal crackers are used to produce ethylene, propylene, butylene and other important olefin intermediates. The ethylene industry requires development of an on-line method for gauging the thickness of coke deposits in cracking furnaces because the current lack of detailed knowledge of coke deposition profiles introduces the single greatest uncertainty in the simulation and control of modern cracking furnaces. The laser ultrasonic coke detector will provide operators with valuable new information allowing them to better optimize the decoking turnaround schedule and therefore maximize production capacity.