Particle filter

Claim 1

A METHOD OF OPERATING A FLUIDIZED BED REACTOR, SAID REACTOR HAVING A REACTOR VESSEL, A BED OF PARTICULATE SOLIDS HAVING A PREDETERMINED MINIMUM PARTICLE SIZE CONTAINED IN THE VESSEL, A GAS INLET MEANS HAVING AN ORIFICE IN THE VESSEL, FIRST AND SECOND GAS OUTLET MEANS HAVING ORIFICES WITHIN THE VESSEL, THE ORIFICE OF THE SECOND GAS OUTLET MEANS BEING LOCATED AT AN INTERMEDIATE POSITION IN THE VESSEL BETWEEN THE ORIFICE OF THE FIRST GAS OUTLET MEANS AND THE GAS INLET MEANS, A POROUS MEMBRANE COVERING THE ORIFICE OF SAID GAS OUTLET MEANS HAVING A PORE SIZE WHICH IS SMALLER THAN THE MINIMUM PARTICLE SIZE OF THE SOLIDS; COMPRISING; THE STEP OF PASSING A GAS THROUGH SAID GAS INLET MEANS AND SAID SOLIDS WHILE REMOVING ALL OF SAID PASSED GAS FROM SAID VESSEL OUT THROUGH SAID FIRST GAS OUTLET MEANS AT A RATE SUFFICIENT TO CAUSE FLUIDIZATION OF SAID SOLIDS WHILE SIMULTANEOUSLY PREVENTING SAID PASSED GAS FROM PASSING THROUGH THE SECOND GAS OUTLET MEANS; ADJUSTING THE POSITION OF THE MEMBRANE COVERED ORIFICE OF THE SECOND GAS OUTLET MEANS SO AS TO CONTACT IT WITH THE FLUIDIZED SOLIDS; THEREAFTER CAUSING SAID PASSED GAS TO BE REMOVED FROM SAID VESSEL THROUGH SAID SECOND GAS OUTLET MEANS WHILE SIMULTANEOUSLY PREVENTING SAID GAS FROM PASSING THROUGH SAID FIRST GAS OUTLET MEANS SO AS TO CAUSE A STATIC BED OF AT LEAST A PORTION OF THE FLUIDIZED SOLIDS TO ADHERE TO SAID MEMBRANE.