(242f) A Tool for Understanding Foaming Tendencies, Coke Morphology, and Quench Effectiveness - Real Time Visualization into Pilot Delayed Coker Drum

Authors: 
Waturuocha, A., University of Tulsa
Banerjee, D., University of Tulsa
Volk, M., University of Tulsa
Mavarez Nava, G., University of Tulsa
Wisecarver, K., University of Tulsa
Bitumen and extra heavy oils are a major source of unconventional oils. The challenge with processing these types of oils is the high proportion of components boiling at greater than 1000°F i.e. the un-distillable vacuum residue. This un-distillable fraction is typically sent to the delayed coker. During the delayed coking process operators face problems such as foaming, changing coke morphology, or hot spots during decoking that can adversely affect the profitability and safety of the process. In commercial operations, the sources of these problems are difficult to identify. Industry is thus in need of quality data related to these problems to optimize their coke drum performance which may be otherwise costly and time consuming to obtain.

This paper will discuss how a real-time tool, a moving gamma-ray densitometer, attached to a pilot scale delayed coker is used in conjunction with other information obtained from the same unit for investigating and understanding foaming tendencies in the coke drum, coke morphology and quench effectiveness which is related to hot spot formation. This direct measurement device; a gamma-ray densitometer coupled with an automatic lifting system provides the density of the coke drum contents along its length every 1.5 minutes. It allows for real time visualization of the changes occurring inside the drum as the thermal reactions progress. From these time-dependent density scans, foaming events, foam collapse, and re-foam are easily identified and modeled as a function of operating conditions and feed properties. The effectiveness of antifoam agents are also evaluated using this tool. Mesophase to coke transitions, as well as coke densification (which is predominant in mixed morphology coke) are also modeled using data obtained from this densitometer along with pressure drop data and capillary pressure measurements on coke samples. Real-time quench effectiveness is evaluated using a combination of the temperature profile of the drum and the density scans which gives an indication for dense regions in the coke bed.

This continuously moving and scanning vertical gamma densitometer attached to a delayed coker pilot, providing real time visualization has proved to be a versatile and useful research tool that aids in understanding and modeling events that occur while changing operating parameters in a delayed coke drum. The data may be able to predict previously un-predictable events which could increase safety of operation and/or lower Capex and Opex.

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