259035 Study of Heavy Crude Flows in Pipelines with Electromagnetic Heaters

Monday, October 29, 2012: 10:50 AM
301 (Convention Center )
Ricardo Dunia, Chemical Engineering Department, The University of Texas at Austin, Austin, TX and Thomas F. Edgar, McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX

The electromagnetic heating of heavy crude oil in cylindrical pipes represents a novel technique to reduce fluid viscosity and diminish the cost required for its transportation [1]. The efficiency of electromagnetic heaters (EH) depends of the material to be heated and the reflective electromagnetic properties of the enclosure. In that way losses can be minimized and the energy generated by the electromagnetic field source can be readily absorbed by the processing material. The distribution of electromagnetic heating devices in pipelines between oil producers and consumers may provide a considerable advantage when compared to the high operational costs of fired-heaters and heavy equipment pump stations [2]. Furthermore, electromagnetic heaters can be placed within pump stations to reduce the crude oil viscosity. The figure below illustrates the use of EH to increase the distance between oil pump stations. Notice how the pressure profile can be impacted by the placement of an electromagnetic heater to the point that fewer pumping stations may be required between producers and consumers of heavy oil.

Figure: Crude oil transportation diagram and pipe pressure profiles. Top diagram shows the case of no intermediate heating between pump-stations. The energy loss due to high viscosity at low temperatures forces a separation of only Y miles between stations. The installation of an electromagnetic heater (EH) between pump-stations (bottom diagram) allows an extra separation of DY miles between stations, reducing the number of stations and pump head required for significant transportation distances.

In this study the oil viscous fluid momentum and energy balances, which include the effects of electromagnetic heating, variable viscosity and fluid dielectric properties, are solved in cylindrical coordinates [3]. The electromagnetic energy absorbed by oil is converted into sensible heat, which could significantly reduce the viscosity of heavy crude fluids. This drop in fluid viscosity diminishes flow pressure losses in pipelines, which potentially reduces the number and size of pumping stations between oil producers and consumers.

Different pipe materials are considered here to determine the effect of their dielectric properties in the fluid flow. Simulation results show that pipe materials with large electromagnetic absorption tend to attenuate the pipe interior electromagnetic field, which reduces the direct warming of the fluid. This significant reduction in the direct fluid heating suggests that pipes made by transparent electromagnetic materials are preferred for this type of applications.

The simulations presented in this work provide a first step in the estimation of electromagnetic heating for heavy crude transportation. An economic analysis of using electromagnetic heaters was made to maximize the distance between pump stations in a long pipeline stretch. The simulation results demonstrate that the use of electromagnetic heaters increases by 30% the distance between pump stations.

References

[1] Carrizales, M.; Lake, L. W. Two-Dimensional COMSOL Simulation of Heavy-Oil Recovery by Electromagnetic Heating. 2009.

[2] Martinez-Palou, R.; Mosqueira, M. d. L.; Zapata-Rendon, B.; Mar-Juarez, E.; Bernal- Huicochea, C.; Clavel-Lopez, J. d. l. C.;

Aburto, J. Journal of Petroleum Science and Engineering 2011, 75, 274282.

[3] Dunia, R.; Edgar, T. Use of Electromagnetic Heaters for Heavy Crude Oil Transportation. Submitted to Energy & Fuels 2012.


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