Heavy oil upgrading experiments were conducted using a variable frequency microwave. While microwave energy itself is readily available as a laboratory technique, microwave ovens that produce frequencies other than 2450 MHz are not. We were able to determine the effect of frequency, by using a variable fre- quency unit at a facility in North Carolina.

Results were promising despite the rapid screening which was employed. Experimental variables included additives, reaction time, and frequency. The addition of activated carbon produced an oil that met pipeline specifications for viscosity and density.

Coke formation determined only on the molybdic acid–iron powder combination; was less than 2 wt.%. This encouraging coke finding may indicate a low coking propensity due to selective heating whereby the bulk of the sample remains at cooler temperatures and reactions are carried out very rapidly.

Overall, the experimental results emphasized that different combinations of material interacted differently at different frequencies. This finding is of utmost importance because the screening of additives has traditionally been focused on 2450 MHz and 915 MHz, which — depending upon the reactants — may not be appropriate for optimum interaction. Frequency was found to have a marked effect upon upgrading.

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