Delayed coking process for producing anisotropic free-flowing shot coke

Abstract

A delayed coking process wherein substantially all of the coke produced is free-flowing anisotropic shot coke. A coker feedstock, such as a vacuum residuum, is treated with an oxidizing agent, such as air, to increase the level of one or more of asphaltenes, polars, and organically bound oxygen groups. The oxidized feedstock is then heated to coking temperatures and passed to a coker drum for an effective amount of time to allow volatiles to evolve and to produce a substantially free-flowing anisotropic shot coke.

1 . A delayed coking process wherein substantially all of the coke produced is substantially free-flowing anisotropic shot coke, which processes comprises: 
 a) contacting a vacuum residuum feed with an oxidizing agent at a temperature from about 150° C. to about 325° C. for an effective amount of time to significantly increase the amount of one or more of asphaltenes, polars, and organically bound oxygen groups in the resid;    b) heating said oxidized resid feed to a temperature effective for coking said feed;    c) charging said heated oxidized resid to a delayed coker drum at a pressure from about 15 to 50 psig for an effective amount of time to produce volatiles and anisotropic substantially free-flowing shot coke;    d) removing at least a portion of said volatiles overhead; and    e) removing the product anisotropic substantially free-flowing shot coke from the coker drum.    
     
     
         2 . The process of  claim 1  wherein the oxidizing agent is selected from air, oxygen, ozone, hydrogen peroxide, organic peroxides, hydroperoxides, inorganic peracids, inorganic oxides and peroxides and salts of oxides, sulfuric acid, and nitric acid.  
     
     
         3 . The process of  claim 2  wherein the oxidizing agent is selected from air, oxygen, and ozone.  
     
     
         4 . The process of  claim 3  wherein the oxidizing agent is air.  
     
     
         5 . The process of  claim 1  wherein the temperature at which the residuum is treated with the oxidizing agent is from about 185° C. to about 280° C.  
     
     
         6 . The process of  claim 1  wherein an aqueous caustic is added to the residuum before, during, or after being heated to coking temperatures.  
     
     
         7 . The process of  claim 6  wherein an aqueous caustic is added to the residuum after being heated to coking temperatures.  
     
     
         8 . The process of  claim 1  wherein the particle size of the shot coke is from about {fraction (1/16)} to ⅜ inch.  
     
     
         9 . The process of  claim 1  wherein the microstructure of the resulting substantially free-flowing anisotropic coke is characterized as being comprised of substantially discrete domains from about 1 to 10 μm in average size.  
     
     
         10 . A delayed coking process comprising: 
 a) contacting a vacuum residuum with an effective amount of air at a temperature from about 150° C. to about 325° C. for an effective amount of time to significantly increase the amount of one or more of asphaltenes, polars, and organically bound oxygen in the residuum;    b) heating said oxidized residuum to a temperature effective for coking said feed;    c) charging said heated oxidized residuum to a delayed coker drum at a pressure from about 15 to 50 psig for an effective amount of time to produce volatiles and a substantially free-flowing anisotropic shot coke;    d) removing at least a portion of the volatiles overhead;    e) quenching the remaining hot coke bed with water;    f) removing the resulting anisotropic substantially free-flowing shot coke product from the coker drum.    
     
     
         11 . The process of  claim 10  wherein the temperature at which the residuum is treated with the oxidizing agent is from about 185° C. to about 280° C.  
     
     
         12 . The process of  claim 10  wherein an aqueous caustic is added to the residuum before, during, or after being heated to coking temperatures.  
     
     
         13 . The process of  claim 12  wherein an aqueous caustic is added to the residuum after being heated to coking temperatures.  
     
     
         14 . The process of  claim 10  wherein the particle size of the shot coke is from about {fraction (1/16)} to ⅜ inch.  
     
     
         15 . The process of  claim 10  wherein the microstructure of the resulting substantially free-flowing anisotropic coke is characterized as being comprised of substantially discrete domains having an average size of about 1 to 10 μm.