Direct stripping cyclone
View Patent ↗Systems and methods for the separation of a particulate-fluid suspension are provided. An apparatus for the separation of a particulate-fluid suspension can include an enclosed vessel having two or more sections disposed coaxially along a common longitudinal centerline, wherein a first section has a first cross sectional area, and a second section has a second cross sectional area. A plurality of apertures can be disposed about the second section. The apparatus can have a cylindrical surface, parallel to the longitudinal centerline of the apparatus, disposed within the first section. A fluid distribution channel having a plurality of apertures can be disposed either about an exterior surface or an interior of the apparatus. A plurality of fluid conduits can provide fluid communication between the fluid distribution channel and the plurality of apertures distributed about the second section.
1. A method for stripping particulates from a particulate-fluid suspension, comprising:
introducing the particulate fluid-suspension to a vessel comprising two or more internal sections disposed coaxially along a common longitudinal centerline, wherein a first section has a first cross sectional area, and a second section has a second cross sectional area;
selectively separating the particulate fluid-suspension to provide an essentially particulate-free fluid fraction flowing in a first direction, and an essentially fluid-free particulate fraction flowing in a second direction within the first section, wherein the essentially particulate-free fluid fraction has a solids concentration of less than about 5wt % solids;
settling the essentially fluid-free particulate fraction into the second section to provide one or more settled particulates therein;
supplying one or more stripping fluids from an external fluid supply;
introducing the one or more stripping fluids to a distribution channel disposed about the second section;
flowing the one or more stripping fluids, via a plurality of fluid conduits, from the distribution channel to a plurality of apertures disposed on the second section; and
flowing the one or more stripping fluids through the second section to form therein a fluidized bed comprising the one or more stripping fluids and the one or more settled particulates,
wherein about 95% or more of any particulates in the particulate fluid-suspension are withdrawn from the second section when the stripping fluid has an upward velocity of about 0.9 m/s or more.
2. The method of claim 1 , wherein the first and second sections are maintained at an internal pressure equal to or greater than ambient, external, pressure.
3. The method of claim 1 , wherein at least 99% of the fluid in the particulate fluid-suspension introduced to the vessel is withdrawn from the first section.
4. The method of claim 1 , wherein the first cross sectional area is greater than the second cross sectional area.
5. The method of claim 1 , wherein at least a portion of the one or more settled particulates are withdrawn from the second section, and wherein the essentially fluid-free particulate fraction has a particulate concentration of about 90% or more.
6. The method of claim 5 , wherein the level of the fluidized bed in the second section is maintained by controlling the withdrawal rate of the one or more settled particulates from the second section.
7. The method of claim 1 , wherein the vessel is located within a fluid catalytic cracker (FCC) vessel and the particulate-fluid suspension comprises one or more cracking catalysts suspended in a gas comprising one or more cracked hydrocarbons.