PURPOSE: To enhance the separation efficiency of impurities and to shorten a separation time, by arranging plural pairs of electrode pairs each formed by opposing an earth electrode and a high voltage electrode one over the other in a desalting tank.
CONSTITUTION: Oil to be treated is supplied into a desalting tank 101 from a supply pipe 102 through a distribution pipe 103 and fine water droplets in oil are mutually coalesced in the electric field between upper electrode pair 105 to enlarge the diameter of each water droplet and further coalesced in the electric field between lower electrode pair 106 to form large diameter water droplets which are, in turn, precipitated by gravity. As mentioned above, because water droplets are separated over two stages, impurities can be separated with good efficiency within a short time and, because it is unnecessary to increase voltage applied between electrodes, no danger of spark discharge is generated.
MITSUTAKE HIDETO
ENDOU KATSUMI
