Composition useful in sulfate scale removal
The present invention discloses a novel aqueous composition for use in removing petroleum-contaminated barium sulfate scale from a surface contaminated with such, said composition comprising: a chelating agent and a counterion component selected from the group consisting of: Li 5 DTPA; Na 5 DTPA; K 5 DTPA; Cs 5 DTPA; Na 4 EDTA; K 4 EDTA; TEAH 4 DTPA; and TBAH 5 DTPA; a scale removal enhancer; a non-ionic surfactant; and a hydrotrope. There is also disclosed methods to use such compositions.
1. An aqueous composition for use in removing petroleum-contaminated barium sulfate scale from a surface contaminated with the same, said composition comprising:
a chelating agent and a counterion component selected from the group consisting of: Li 5 DTPA; Na 5 DTPA; K 5 DTPA; Cs 5 DTPA; Na 4 EDTA; K 4 EDTA; TEAH 4 DTPA; and TBAH 5 DTPA;
a scale removal enhancer;
a non-ionic surfactant; and
a hydrotrope,
wherein the composition has a pH ranging from 10 to 11.
2. The aqueous composition according to claim 1 , wherein the hydrotrope is selected from the group consisting of: alkyl glucosides and alkyldiphenyloxide disulfonates.
3. The aqueous composition according to claim 2 , wherein the alkyldiphenyloxide disulfonate is Disodium Hexyl Diphenyl Ether Disulfonate.
4. The aqueous composition according to claim 2 , wherein the alkyl glucoside is a C 6 -C 12 alkyl glucoside.
5. The aqueous composition according to claim 1 , wherein the hydrotrope is a C 6 -C 12 alkyl glucoside selected from the group consisting of: hexyl glucoside; octyl glucoside; decyl glucoside; dodecyl glucoside and combinations thereof.
6. The aqueous composition according to claim 1 , wherein the scale removal enhancer is selected from the group consisting of: potassium carbonate; potassium formate; cesium formate; cesium carbonate; and combinations thereof.
7. The aqueous composition according to claim 1 , wherein the non-ionic surfactant is selected from the group consisting of: linear alcohol ethoxylate surfactants and branched alcohol ethoxylate surfactants.
8. The aqueous composition according to claim 1 , wherein the non-ionic surfactant is a linear alcohol ethoxylate surfactant selected from the group consisting of: alcohol ethoxylate surfactants having a chain length of at least 6 carbon atoms.
9. The aqueous composition according to claim 1 , wherein the scale removal enhancer is present in the composition in an amount ranging from 5 to 20 wt % of the composition.
10. The aqueous composition according to claim 1 , wherein the chelating agent and counterion are present in the composition in an amount ranging from 5 to 40 wt % of the composition.
11. The aqueous composition according to claim 1 , wherein the scale removal enhancer is selected from the group consisting of: K 5 DTPA; Cs 5 DTPA; Na 4 EDTA; and K 4 EDTA.