Liquid solids contacting

Claim 1

A CONTINUOUS PROCESS FOR THE COUNTERCURRENT CONTACTING OF LIQUID HYDROCARBON OILS WITH ABSORBENTS OF PALPABLE PARTCULATE FORM IN ORDER TO REMOVE SMALL AMOUNTS OF IMPURITIES FROM THE LIQUID OILS, WHICH COMPRISES: MAINTAINING A COLUMNAR MASS OF ADSORBENT WITHIN A CONFINED TREATING ZONE, SUPPLYING LIQUID OIL CHARGE TO THE LOWER SECTION OF THE MASS AND PASSING THE LIQUID OIL UPWARDLY THROUGH THE MASS AT A VELOCITY INSUFFICIENT TO SUBSTANTIALLY DISRUPT THE MASS AND THEREBY EFFECT THE DESIRED TREATMENT, REMOVING OIL FROM THE UPPER SECTION OF THE TREATING ZONE AT A LEVEL SUBSTANTIALLY ABOVE THE UPPER END OF THE MASS, WHEREBY A LIQUID SURFACE IS FORMED IN THE UPPER SECTION OF THE TREATING ZONE, SUPPLYING ADSORBENT TO THE UPPER SECTION OF THE CONTACTING ZONE THROUGH AN INLET FLOW PASSAGE AND WITHDRAWING ADSORBENT FROM THE LOWER SECTION OF THE TREATING ZONE THROUGH AN OUTLET FLOW PASSAGE, MEASURING THE PRESSURE DIFFERENTIAL DUE TO LIQUID FLOW THROUGH THE MASS BETWEEN A SELECTED LEVEL ABOVE THE UPPER SURFACE OF THE MASS BUT BELOW THE LIQUID SURFACE AND A SELECTED LEVEL BELOW THE UPPER SURFACE OF THE MASS, AND ADJUSTING THE FLOW OF ADSORBENT IN ONE OF SAID FLOW PASSAGES IN RESPONSE TO SAID PRESSURE DIFFERENTIAL MEASUREMENT TO MAINTAIN THE UPPER SURFACE OF THE MASS AT A SUBSTANTIALLY CONSTANT LEVEL WITHIN A PREDETERMINED NARROW RANGE BELOW THE LIQUID SURFACE.