Delayed coking process for producing free-flowing coke using an overbased metal detergent additive

Abstract

A delayed coking process for making substantially free-flowing coke, preferably shot coke. A coker feedstock, such as a vacuum residuum, is heated in a heating zone to coking temperatures then conducted to a coking zone wherein volatiles are collected overhead and coke is formed. An overbased alkaline earth metal detergent additive is added to the feedstock prior to it being heated in the heating zone, prior to its being conducted to the coking zone, or both.

1 . A delayed coking process comprising: 
 (a) heating a petroleum resid in a first heating zone, to a temperature below coking temperatures but to a temperature wherein the resid is a pumpable liquid;    (b) conducting said heated resid to a second heating zone wherein it is heated to coking temperatures;    (c) conducting said heated resid from said second heating zone to a coking zone wherein vapor products are collected overhead and a coke product is formed;    (d) introducing into said resid at least one overbased metal detergent additive that is effective for the formation of substantially free-flowing coke, wherein said overbased metal detergent additive is introduced into said resid at a point upstream of the second heating zone, upstream of said coking zone, or both.    
   
   
       2 . The process of  claim 1  wherein the residuum feedstock is vacuum resid.  
   
   
       3 . The process of  claim 2  wherein at least a portion of the additive is soluble in the feedstock.  
   
   
       4 . The process of  claim 1  wherein the additive is selected from the group consisting of calcium phenate, magnesium phenate, sulfurized calcium phenate, and magnesium phenate wherein each aromatic group has one or more aliphatic groups to impart hydrocarbon solubility.  
   
   
       5 . The process of  claim 1  wherein the additive is selected from calcium sulfonates, and magnesium sulfonates wherein each sulfonic acid moiety is attached to an aromatic nucleus which in turn usually contains one or more aliphatic substituents to impart hydrocarbon solubility.  
   
   
       6 . The process of  claim 1  wherein the additive is selected from calcium salicylates, and magnesium salicylates wherein the aromatic moiety is usually substituted by one or more aliphatic substituents to impart hydrocarbon solubility.  
   
   
       7 . The process of  claim 1  wherein the additive is selected from the calcium and magnesium salts of hydrolyzed phosphosulfurized olefins having 10 to 2,000 carbon atoms or of hydrolyzed phosphosulfurized alcohols and/or aliphatic-substituted phenolic compounds having 10 to 2,000 carbon atoms.  
   
   
       8 . The process of  claim 1  wherein the additive is selected from calcium and magnesium salts of aliphatic carboxylic acids and aliphatic-substituted cycloaliphatic carboxylic acids.  
   
   
       9 . The process of  claim 1  wherein the coke produced is substantially shot coke.  
   
   
       10 . The process of  claim 4  wherein the coke produced is substantially a shot coke.  
   
   
       11 . The process of  claim 1  wherein said overbased metal detergent additive is introduced into said vacuum resid at a point upstream of the first heating zone, upstream of the second heating zone, or both.  
   
   
       12 . A delayed coking process comprising: 
 (a) contacting a vacuum resid with an effective amount of at least one overbased alkaline earth metal detergent additive at a temperature from about 70° C. to about 370° C. for a time sufficient to disperse the agent uniformly into the feed;    (b) heating the treated resid to a temperature effective for coking said feed;    (c) charging said heated treated resid to a coking zone at a pressure from about 15 to 80 psig for a coking time to form a bed of hot coke; and    (d) quenching at least a portion of the bed of hot coke with water.    
   
   
       13 . The process of  claim 12  wherein at least a portion of the additive is soluble in the feedstock.  
   
   
       14 . The process of  claim 12  wherein the additive is selected from the group consisting of calcium phenate, magnesium phenate, sulfurized calcium phenate, and magnesium phenate wherein each aromatic group has one or more aliphatic groups to impart hydrocarbon solubility.  
   
   
       15 . The process of  claim 12  wherein the additive is selected from calcium sulfonates, and magnesium sulfonates wherein each sulfonic acid moiety is attached to an aromatic nucleus which in turn usually contains one or more aliphatic substituents to impart hydrocarbon solubility.  
   
   
       16 . The process of  claim 12  wherein the additive is selected from calcium salicylates, and magnesium salicylates wherein the aromatic moiety is usually substituted by one or more aliphatic substituents to impart hydrocarbon solubility.  
   
   
       17 . The process of  claim 12  wherein the additive is selected from the calcium and magnesium salts of hydrolyzed phosphosulfurized olefins having 10 to 2,000 carbon atoms or of hydrolyzed phosphosulfurized alcohols and/or aliphatic-substituted phenolic compounds having 10 to 2,000 carbon atoms.  
   
   
       18 . The process of  claim 12  wherein the additive is selected from calcium and magnesium salts of aliphatic carboxylic acids and aliphatic-substituted cycloaliphatic carboxylic acids.  
   
   
       19 . The process of  claim 12  wherein the coke produced is substantially a shot coke.