In transitive terms the difference between percolate and circulate
is that
percolate is to make (coffee) in a percolator while
circulate is to cause (a person or thing) to move in circles or through a circuit.
In intransitive terms the difference between percolate and circulate
is that
percolate is to drain or seep through a porous substance while
circulate is to move in circles or through a circuit.
As a noun percolate
is a liquid that has been percolated.