Rendering of a prototype that would electrokinetically remove asphaltenes from crude oil near the point of production. Image credit: Yao et al., 2015, Department of Petroleum Engineering, University of Houston
The asphaltene fraction of crude oil tends to precipitate out of solution and deposit inside pipes, pumps and other production equipment. The resulting blockage is usually treated through the use of chemical dispersants and deployment of a ‘pig’ to remove deposited solids. A more efficient approach is being developed by University of Houston engineers: a device that removes asphaltenes from crude oil near the point of production.
A scaled-down prototype was assembled and tested to demonstrate the potential of using electrokinetics to prevent blockages. Two electrical plates, charged at 4,000 V, are inserted into the pipe. The model oil used consisted of a 30:70 mixture of heptane and toluene by volume, called “heptol-70,” to which asphaltenes were added (2 wt%).The plates attracted the asphaltene, removing it from the flowing oil. The efficiency of the electrokinetic process was judged to be high for the range of flow rates tested.
Future work will involve using a wider variety of solvents and, ultimately, a prototype that can be used with produced crude.
