Method for passing a fluid through a moving bed of particles

A process for passing a fluid through a bed of particulate material, the process comprising:

• a) maintaining particulate material in a vertically extended bed having a fluid inlet face, wherein the bed is maintained between the fluid inlet face and an outlet partition having a perforated section extending over at least part of its length, wherein the size of the perforations retains the particulate material while permitting fluid flow therethrough;
• b) passing an inlet fluid to the fluid inlet face and transversely through the bed;
• and
• c) withdrawing the particulate material from the bottom of the bed at a rate to achieve a desired solid fraction of the bed while recovering outlet fluid from the perforated section of the outlet partition at an operating flow rate that is not less than a stagnant bed pinning flow rate corresponding to the desired solid fraction of the bed.