(29h) Study of Heavy Crude Flows in Pipelines with Electromagnetic Heaters

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, 274?282.

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