(431a) Design Insights for a Thermal Visbreaking Pilot Based on Microwave Heating

The transport of heavy oil by pipeline typically requires a significant reduction in the oil viscosity, which is often accomplished with a diluent. It is tempting to reduce or eliminate the need for diluent by performing some form of mild thermal cracking or viscosity breaking (visbreaking) of the heavy oil at the well-site prior to transport. The objective of this study was to evaluate the application of electromagnetic (EM) energy to a typical visbreaking (heater-soaker) reactor design where flowing heavy oil was heated in a microwave resonant cavity. The design concept was tested on laboratory scale reactor and it was demonstrated that the microwave resonant cavity could heat the heavy oil while maintaining efficient transfer of microwave energy to heating (over 80%). This heating significantly changed the oil composition and properties, including an order of magnitude reduction in viscosity [1,2].

The study also addressed two unique challenges in scaling results from the laboratory scale microwave reactor to a 1000 bbl/day pilot design: i) defining the dimensions of the resonant cavity to handle the 1000 bbl/day flow rate while maintaining the desired heating efficiency, and ii) identifying the tolerance of the microwave resonant cavity performance to produced water in the heavy oil feed (measured by resonance frequency and energy adsorption distribution). The first challenge was met by reducing the resonant frequency of the reactor by increasing the reactor tube diameter and using a modular heater-soaker unit design [3]. The second challenge was tackled using CST^TM simulation to model the EM behavior in the presence of water saturated heavy oil, emulsion and steam at reactor conditions. It was demonstrated that the reactor could tolerate a maximum water content in the range of 1 wt% before the reactor performance degraded.

[1] Taylor S.D., Andersen, S.I., Tam, W.M., Neitz, T., O’Brien, D., Pulikkathara, M., and Saeedfar, A., “A Thermal Visbreaking Prototype Based on Microwave Heating”, 65th Canadian Chemical Engineering Conference, Calgary, Canada, 4-7 October 2015.

[2] T. Neitz, W-M. Tam, B. Clark, S.D. Taylor, D. O'Brien, Y. Cheng, A. Saeedfar, "Apparatus and Method Employing Microwave Resonant Cavity Heating of Hydrocarbon Fluid", (2013) WO 2014/189533.

[3] D. O'Brien, A. Saeedfar, S.D. Taylor, B. Clark, W.-M. Tam, M. Pulikkathara, T. Neitz, S. Andersen "Apparatus and Method Employing Microwave Resonant Cavity Heating for Visbreaking of Hydrocarbon Fluid", (2013) WO 2014/171960.