Inhibiting corrosion caused by aqueous aldehyde solutions

Abstract

Aldehydes useful as H 2 S sulfide scavengers may be corrosive to some metals such as steel, iron and aluminum, but the corrosive effect of the aldehydes may be mitigated by employing a corrosion inhibitor selected from the group consisting of a di-basic soluble phosphate salt, a tri-basic soluble phosphate salt, and combinations thereof.

1 . A method for employing an aldehyde in an aqueous solution while mitigating corrosion of metal in contact with the aldehyde solution, the method comprising employing a corrosion inhibitor with the aldehyde wherein the corrosion inhibitor comprises a member selected from the group consisting of a mono-basic soluble phosphate salt, a di-basic soluble phosphate salt, a tri-basic soluble phosphate salt, and combinations thereof. 
     
     
         2 . The method of  claim 1  wherein the aldehyde is selected from the group consisting of glyoxal, acrolein, glutaraldehyde, formaldehyde, and combinations thereof. 
     
     
         3 . The method of  claim 1  wherein the member selected from the group consisting of a mono-basic soluble phosphate salt, a di-basic soluble phosphate salt, a tri-basic soluble phosphate salt, and combinations thereof is selected from the group consisting of LiH 2 PO 4 , NaH 2 PO 4 , Na 2 HPO 4 , Na 3 HPO 4 , KH 2 PO 4 , K 2 HPO 4 , K 3 HPO 4  and combinations thereof. 
     
     
         4 . The method of  claim 1  wherein the member selected from the group consisting of a mono-basic soluble phosphate salt, a di-basic soluble phosphate salt, a tri-basic soluble phosphate salt, and combinations thereof includes more than one cation. 
     
     
         5 . The method of  claim 4  wherein the member selected from the group consisting of a mono-basic soluble phosphate salt, di-basic soluble phosphate salt, a tri-basic soluble phosphate salt, and combinations thereof includes two or more cations selected from the group consisting of lithium, potassium, sodium and combinations thereof. 
     
     
         6 . The method of  claim 1  wherein the aqueous aldehyde solution has an aldehyde concentration of from about 20 to about 90 weight percent. 
     
     
         7 . The method of  claim 1  wherein the member selected from the group consisting of a mono-basic soluble phosphate salt, a di-basic soluble phosphate salt, a tri-basic soluble phosphate salt, and combinations thereof is present in the aqueous aldehyde solution at a concentration of from about 100 ppm to 30% (by wt.). 
     
     
         8 . The method of  claim 1  wherein the aldehyde and corrosion inhibitor solution is employed at a pH range of from about 4.0 to about 9.0. 
     
     
         9 . The method of  claim 8 , wherein the pH range may vary from about 4.5 to about 9. 
     
     
         10 . A process for exploring for or producing crude oil and/or natural gas comprising employing a H 2 S sulfide scavenger solution comprising an aldehyde and employing a corrosion inhibitor in the solution comprising a member selected from the group consisting of a mono-basic soluble phosphate salt, a di-basic soluble phosphate salt, a tri-basic soluble phosphate salt, and combinations thereof. 
     
     
         11 . The process of  claim 10  wherein the aldehyde is selected from the group consisting of glyoxal, acrolein, glutaraldehyde, formaldehyde, and combinations thereof. 
     
     
         12 . The process of  claim 10  wherein the member selected from the group consisting of a mono-basic soluble phosphate salt, a di-basic soluble phosphate salt, a tri-basic soluble phosphate salt, and combinations thereof is selected from the group consisting of LiH 2 PO 4 ; NaH 2 PO 4 , Na 2 HPO 4 ; Na 3 HPO 4 ; KH 2 PO 4 , K 2 HPO 4 ; K 3 HPO 4 ; and combinations thereof. 
     
     
         13 . The process of  claim 10  wherein the member selected from the group consisting of a mono-basic soluble phosphate salt, a di-basic soluble phosphate salt, a tri-basic soluble phosphate salt, and combinations thereof includes more than one cation. 
     
     
         14 . The process of  claim 13  wherein the member selected from the group consisting of a mono-basic soluble phosphate salt, a di-basic soluble phosphate salt, a tri-basic soluble phosphate salt, and combinations thereof includes two or more cations selected from the group consisting of lithium, potassium, sodium, and combinations thereof. 
     
     
         15 . The process of  claim 10  wherein the H 2 S sulfide scavenger solution has an aldehyde concentration of from about 20 to about 90 weight percent. 
     
     
         16 . The process of  claim 10  wherein the member selected from the group consisting of a mono-basic soluble phosphate salt, a di-basic soluble phosphate salt, a tri-basic soluble phosphate salt, and combinations thereof is present in the H 2 S sulfide scavenger solution at a concentration of from about 100 ppm to 30% (by wt.). 
     
     
         17 . The process of  claim 10  wherein the H 2 S sulfide scavenger solution comprising aldehyde and member selected from the group consisting of a mono-basic soluble phosphate salt, a di-basic soluble phosphate salt, a tri-basic soluble phosphate salt, and combinations thereof, has a pH range of from about 4.0 to about 9.0. 
     
     
         18 . The process of  claim 17 , wherein the pH range may vary from about 4.5 to about 9. 
     
     
         19 . The process of  claim 10  wherein the H 2 S sulfide scavenger and corrosion inhibitor is atomized and injected into a gas stream. 
     
     
         20 . The process of  claim 10  wherein the H 2 S sulfide scavenger and corrosion inhibitor is admixed with crude oil.