Generally,improvement of input power means that higher intensity of ultra-sound was introduced into the reactor,which would accelerate the reactions .
Thus sulfur removal was improved with increasing amplitude values.
However,the low volatile hydrocarbons suchas methane, ethylene,ethane,propylene, and C5+ hydrocarbons might be produced due to the cavitation effect and the extent of cracking of oil to produce gases is largely dependent on the ampli-
tude [21], resulting in loss of oil.
Moreover, high amplitude (highinput power) also represents high electricity consumption and leads to the rapid increase of probe temperature .
Therefore,the amplitude was not the higher the better in this UAOD system for treating real heavy oil.