There are wide varieties of chemical processes which are conducted using particles of fluidized particle size suspended in a gaseous phase. Of particular importance in the petroleum industry is the well known fluidized catalytic cracking process (FCC) in which the particles that are fluidized and suspended in a gaseous phase are catalyst particles. In this typical hydroconversion process, it ultimately becomes necessary to separate the particulate material from the fluidizing gas and this is generally achieved in a catalyst separation zone equipped with cyclones.
Recent trends of fluidized catalytic cracking have tended toward operation of the process at higher temperatures with extremely active catalysts. The concomitant result is that there has been an everincreasing necessity to be able to efficiently separate the catalyst from the fluidizing media in an extremely rapid and efficient manner in order to minimize undesirable side reactions. Consequently, there has been a plethora of methods and apparatuses developed to achieve the separation of fluidized catalyst particles from the fluidizing gas.
The following U.S. Patents illustrate the number of apparatuses and methods employed: U.S. Pat. No. 4,070,159; U.S. Pat. No. 4,176,083; U.S. Pat. No. 4,572,780; U.S. Pat. No. 4,606,814; U.S. Pat. No. 4,629,552; U.S. Pat. No. 4,778,660; U.S. Pat. No. 4,792,437; U.S. Pat. No. 4,869,880 and U.S. Pat. No. 4,909,993.
The foregoing patents show various riser termination devices with internal vanes and the like used in an attempt to bring about satisfactory separation of fluidized particles from the entraining gas.
It is an object of the present invention to provide an improved method and an apparatus for removing fluidizable particles from a fluidizing gaseous stream.
It is another object of the present invention to provide an apparatus which will permit the fluidized solid fluid gas mixture to travel directly from a riser into a primary cyclone.
It is another object of the present invention to provide an apparatus which will channel the natural movement of the fluidized solids into the cyclone in such a way as to avoid abrupt diversion of the gas stream and changing of its essential flow pattern as it exits the riser and enters a primary cyclone.