Methods and compositions for reducing stress corrosion cracking

Abstract

Compositions and methods for reducing stress corrosion cracking in steel vessels used for storing and/or transporting ethanol-containing fluids. Additives including oxygen scavengers and film-forming additives can be employed together in such ethanol-containing fluids (e.g., fuel grade ethanol) to mitigate stress corrosion cracking in steel vessels, such as pipelines, storage tanks, rail cars, and/or tanker trucks.

1 . A composition for reducing stress corrosion cracking in steel vessels used for storing and/or transporting ethanol-containing fluids, said composition comprising: an oxygen scavenger and a film-forming additive, wherein said film-forming additive is selected from the group consisting of dipropanol amine, diisopropanol amine, dibutanol amine, and diisobutanol amine. 
     
     
         2 . The composition of  claim 1 , wherein said oxygen scavenger is selected from the group consisting of carbohydrazide, erythorbate, methylethylketoxime, N,N″-diethylhydroxylamine, hydroquinone, acetone oxime, diethyl sulfite, ascorbic acid, acetone azine, urea, biruet, 2,6-di-tert-butyl phenol, butylated hydroxytoluene, and mixtures thereof. 
     
     
         3 . The composition of  claim 1 , wherein said oxygen scavenger comprises ascorbic acid, carbohydrazide, and/or N,N′-diethylhydroxylamine. 
     
     
         4 . (canceled) 
     
     
         5 . The composition of  claim 1 , wherein said film-forming additive comprises diisopropanol amine. 
     
     
         6 . The composition of  claim 1 , wherein said oxygen scavenger and said film-forming additive are present in a weight ratio in the range of from about 1:5 to about 1:10 oxygen scavenger-to-film-forming additive. 
     
     
         7 . The composition of  claim 1 , wherein said oxygen scavenger and said film-forming additive are each substantially soluble in ethanol. 
     
     
         8 . The composition of  claim 1 , wherein said composition is present in the form of a solution of said oxygen scavenger and said film-forming additive dissolved in fuel grade ethanol. 
     
     
         9 . A composition for reducing stress corrosion cracking in steel vessels used for storing and/or transporting ethanol-containing fluids, said composition consisting essentially of: an oxygen scavenger and a film-forming additive, wherein said film-forming additive is selected from the group consisting of dipropanol amine, diisopropanol amine, dibutanol amine, and diisobutanol amine. 
     
     
         10 . The composition of  claim 9 , wherein said oxygen scavenger is selected from the group consisting of carbohydrazide, erythorbate, methylethylketoxime, N,N′-diethylhydroxylamine, hydroquinone, acetone oxime, diethyl sulfite, ascorbic acid, acetone azine, urea, biruet, 2,6-di-tert-butyl phenol, butylated hydroxytoluene, and mixtures thereof; wherein said film-forming additive is selected from the group consisting of diethanol amine, diisopropanol amine, and mixtures thereof. 
     
     
         11 . A method for reducing stress corrosion cracking in a steel vessel used for storing and/or transporting an ethanol-containing fluid, said method comprising: introducing an oxygen scavenger and a film-forming additive into said vessel either concurrently or sequentially with said ethanol-containing fluid. 
     
     
         12 . The method of  claim 11 , wherein said method comprises the step of pretreating said steel vessel by introducing said oxygen scavenger and said film-forming additive into said vessel either concurrently or sequentially with said ethanol-containing fluid in a combined concentration of at least 1,000 parts per million by weight (“ppmw”) based on the weight of said ethanol-containing fluid, thereby forming a pretreated vessel. 
     
     
         13 . The method of  claim 12 , said method further comprising maintaining said pretreated vessel by adding additional oxygen scavenger and additional film-forming additive to said pretreated vessel, wherein said additional oxygen scavenger and said additional film-forming additive are present in a combined amount in the range of from about 1 to about 1,000 ppmw based on the weight of said ethanol-containing fluid. 
     
     
         14 . The method of  claim 11 , wherein said ethanol-containing fluid comprises dissolved oxygen, wherein said oxygen scavenger is added to said ethanol-containing fluid in an amount sufficient to reduce the dissolved oxygen concentration of said ethanol-containing fluid by at least 50 mole percent. 
     
     
         15 . The method of  claim 11 , wherein said oxygen scavenger is added to said ethanol-containing fluid in an amount sufficient to create a molar ratio of said oxygen scavenger to said dissolved oxygen in the range of from about 0.1:1 to about 10:1 oxygen scavenger-to-dissolved oxygen. 
     
     
         16 . The method of  claim 11 , wherein said oxygen scavenger and said film-forming additive are introduced to said vessel substantially simultaneously, wherein said oxygen scavenger and said film-forming additive are present in a molar ratio in the range of from about 1:5 to about 1:10 oxygen scavenger-to-film-forming additive. 
     
     
         17 . The method of  claim 11 , wherein said vessel is selected from the group consisting of a storage tank, a rail car, a pipeline, and a tanker truck; wherein said vessel comprises greater than 50 weight percent steel. 
     
     
         18 . The method of  claim 11 , wherein said oxygen scavenger is selected from the group consisting of carbohydrazide, erythorbate, methylethylketoxime, N,N′-diethylhydroxylamine, hydroquinone, acetone oxime, diethyl sulfite, ascorbic acid, acetone azine, urea, biruet, 2,6-di-tert-butyl phenol, butylated hydroxytoluene, and mixtures thereof; wherein said film-forming additive is selected from the group consisting of diethanol amine, diisopropanol amine, and mixtures thereof. 
     
     
         19 . The method of  claim 11 , wherein said ethanol-containing fluid is fuel grade ethanol, wherein said ethanol-containing fluid comprises a total amount of hydrocarbons in a concentration of less than 5 weight percent, wherein said ethanol-containing fluid comprises water in an amount of less than 3 weight percent, wherein said ethanol-containing fluid comprises dissolved oxygen in an amount in the range of from about 1 to about 50 ppmw. 
     
     
         20 . The method of  claim 11 , wherein said vessel comprises a pipeline, wherein said ethanol-containing fluid is substantially continuously flowing through said pipeline, wherein said method comprises substantially continuously introducing said oxygen scavenger and said film-forming additive to said vessel at a rate sufficient to produce a treated ethanol-containing fluid having a combined concentration of oxygen scavenger and film-forming additive in the range of from about 1 to about 1,000 ppmw. 
     
     
         21 . A composition for reducing stress corrosion cracking in steel vessels used for storing and/or transporting ethanol-containing fluids, said composition comprising: an oxygen scavenger and a film-forming additive, wherein at least a portion of said oxygen scavenger and at least a portion of said film-forming additive are dissolved in an ethanol-containing fluid, wherein said ethanol-containing fluid comprises ethanol in an amount of at least 50 weight percent. 
     
     
         22 . The composition of  claim 21 , wherein said ethanol-containing fluid is fuel grade ethanol. 
     
     
         23 . The composition of  claim 21 , wherein said film-forming additive has the following structure:
 formula (I):   
       
         
           
           
               
               
           
         
         wherein R 1  and R 2  of formula (I) can independently be any substituted or unsubstituted, saturated or unsaturated, straight-chain or branched alkylene or arylene groups having a carbon number of from 1 to 20, and may include heteroatoms. 
       
     
     
         24 . The composition of  claim 21 , wherein said film-forming additive is selected from the group consisting of dipropanol amine, diisopropanol amine, dibutanol amine, and diisobutanol amine. 
     
     
         25 . The composition of  claim 21 , wherein said film-forming additive comprises diisopropanol amine. 
     
     
         26 . The composition of  claim 21 , wherein said oxygen scavenger is selected from the group consisting of carbohydrazide, erythorbate, methylethylketoxime, N,N″-diethylhydroxylamine, hydroquinone, acetone oxime, diethyl sulfite, ascorbic acid, acetone azine, urea, biruet, 2,6-di-tert-butyl phenol, butylated hydroxytoluene, and mixtures thereof. 
     
     
         27 . The composition of  claim 21 , wherein said oxygen scavenger comprises ascorbic acid, carbohydrazide, and/or N,N′-diethylhydroxylamine.