Cavitation enhanced liquid atomization

Abstract

A cavitation enhanced atomizing process comprises forming a flowing solution of the liquid to be atomized and a lower boiling cavitating liquid. This flowing solution is then contacted with a pressure reducing means, at a temperature below the bubble point of the cavitating liquid in the solution, to produce cavitation bubbles. These bubbles comprise cavitation liquid vapor and the bubble nucleation produces a two-phase fluid of the bubbles and liquid solution. The two-phase fluid is passed downstream into and through an atomizing means, such as an orifice, and into a lower pressure atomizing zone, in which the bubbles vaporize to form a spray of liquid droplets. The nucleated bubbles also grow in size as the so-formed two-phase fluid passes downstream to and through the atomizing means.

1 . A process for atomizing a liquid FCC feed comprises: 
 (a) contacting a flowing fluid, under pressure and comprising a solution of FCC feed oil and a cavitating liquid which comprises one or more hydrocarbon liquids or fractions containing material which boils below the boiling range of said oil feed, with a pressure drop means to reduce the pressure of said flowing fluid and produce nucleation of bubbles comprising vapor of said cavitating liquid at a temperature below the bubble point of said solution, to form a two-phase fluid comprising said bubbles and liquid solution;    (b) passing said two-phase fluid downstream into and through an atomizing means into an atomizing zone which is at a pressure lower than that of said fluid upstream of said atomizing means, to atomize said fluid and form a spray comprising liquid droplets of said feed oil, wherein said atomizing zone comprises a cat cracking reaction zone, and    (c) contacting said spray with a particulate, hot, regenerated cracking catalyst in said reaction zone at reaction conditions effective to catalytically crack said feed oil and produce lower boiling hydrocarbons.    
     
     
         2 . A process according to  claim 1  wherein said bubbles also grow in size upstream of said atomizing means.  
     
     
         3 . A process according to  claim 2  wherein said lower boiling hydrocarbons are separated from said spent catalyst particles and are recovered.  
     
     
         4 . A process according to  claim 3  wherein said cracking reaction also produces spent catalyst particles, which contain strippable hydrocarbons and coke.  
     
     
         5 . A process according to  claim 4  wherein said spent catalyst particles are stripped in a stripping zone, to remove said strippable hydrocarbons to produce stripped, coked catalyst particles.  
     
     
         6 . A process according to  claim 5  wherein said stripped, coked catalyst particles are passed into a regeneration zone, in which they are contacted with oxygen, at conditions effective to bum off said coke and produce said hot, regenerated catalyst particles.  
     
     
         7 . A process according to  claim 6  wherein said pressure drop produced by said pressure reducing means is less than 50 psi.  
     
     
         8 . A process according to  claim 7  wherein at least 0.5 wt. % of said flowing fluid is vaporized by said bubble nucleation and subsequent liquid atomization.  
     
     
         9 . A process according to  claim 8  wherein said hot, regenerated catalyst particles are passed into said cracking reaction zone in which they contact said spray to catalytically crack said feed oil.  
     
     
         10 . A process according to  claim 9  wherein said pressure reducing means comprises at least one static mixer means.  
     
     
         11 . A process according to  claim 9  wherein said atomizing means comprises an atomizing orifice.  
     
     
         12 . A process according to  claim 9  wherein said pressure reducing means reduces said pressure by less than 15 psi.  
     
     
         13 . A process according to  claim 12  wherein said recovered hydrocarbons are further processed.  
     
     
         14 . A process comprising the steps of: 
 (a) combining an FCC feed having a boiling range with a liquid cavitation fluid to form a liquid solution, the cavitation fluid having a boiling range less than the boiling range of the FCC feed;    (b) reducing the pressure of the liquid solution an amount sufficient to produce nucleation of bubbles, the bubbles comprising vapor of the cavitation fluid, thereby forming a two-phase fluid;    (c) flashing the cavitation fluid in the two-phase fluid, thereby atomizing the FCC feed;    (d) contacting the atomized FCC feed with a catalytic cracking catalyst in a reaction zone of an FCC unit.    
     
     
         15 . A process according to  claim 14  wherein the pressure of the liquid solution is reduced less than 50 psi.  
     
     
         16 . A process according to  claim 14  wherein the pressure of the liquid solution is reduced between about 1 and about 5 psi.  
     
     
         17 . A process according to  claim 14  wherein at least 0.5 wt % of the liquid solution has been vaporized before entering the reaction zone.  
     
     
         18 . A process according to  claim 14  wherein at least 1.0 wt % of the liquid solution has been vaporized before entering the reaction zone.  
     
     
         19 . A process according to  claim 14  wherein the pressure of the liquid solution is reduced in a static mixer.  
     
     
         20 . A fluid catalytic cracking process comprising the steps of: 
 (a) combining an FCC feed having a boiling range with a liquid cavitation fluid to form a solution, the cavitation fluid having a boiling range less than the boiling range of the FCC feed;    (b) reducing the pressure of the liquid solution between about 1 and about 5 psi to form bubbles comprising vapor of the cavitation fluid, thereby forming a two-phase fluid;    (c) flashing the cavitation fluid in the two-phase fluid, thereby atomizing the FCC feed;    (d) contacting the atomized FCC feed with a catalytic cracking catalyst in a reaction zone of an FCC unit to produce cracked products, vaporized cavitation fluid, and spent catalyst;    (e) separating the cracked products from the spent catalyst particles in a separation zone;    (f) stripping the spent catalyst particles in a stripping zone to remove the strippable hydrocarbons;    (g) recovering the cracked products, strippable hydrocarbons, and the vaporized cavitation fluid;    (h) passing the stripped, spent catalyst into a regeneration zone and contacting the catalyst particles with an oxygen-containing gas to produce regenerated catalyst particles; and,    (i) passing the regenerated catalyst particles to the reaction zone.    
     
     
         21 . A process comprising the steps of: 
 (a) combining an FCC feed having an initial boiling point above about 232° C. with a cavitation fluid to form a solution, the cavitation fluid having a boiling range less than about 232° C.;    (b) reducing the pressure of the solution an amount sufficient to form bubbles comprising vapor of the cavitation fluid, thereby forming a two-phase fluid;    (c) flashing the cavitation fluid in the two-phase fluid, thereby atomizing the FCC feed;    (d) contacting the atomized FCC feed with a catalytic cracking catalyst in a reaction zone of an FCC unit.    
     
     
         22 . A process according to  claim 14  wherein the amount of liquid solution is from 0.1 to 10 wt. %, based on flowing fluid.  
     
     
         23 . A process according to  claim 8  wherein the amount of cavitating liquid is from 0.1 to 10 wt. %, based on flowing fluid.