Study on the synergistic effect of NaOH and CuSO4 in aquathermolysis upgrading

The development of heavy oil has become increasingly important due to the demand of human society for energy. The in-situ upgrading is a technology using transition metal catalyst to reduce heavy oil viscosity to enhance oil recovery. This work revealed the Cu atoms of CuSO4 entered the heavy oil molecules to increase viscosity, and the NaOH can inhibit this viscosity increasing effect to improve the catalyst activity of CuSO4. The composite catalyst NaOH/CuSO4 was proved to decrease the viscosity by 81.43% at 300 degrees C. The further analysis showed that the effect of NaOH was attributed to the competitive reaction mechanism and production of the Cu and CuOx. These conclusions are helpful to understand the aquathermolysis upgrading mechanism and develop the inexpensive and efficient composite catalyst.