Environmentally preferable microemulsion composition

1. A microemulsion composition comprising:

a glycol ether in an amount of 2 to 30% by weight, wherein the glycol ether is a compound according to Formula I:

R 1 O[(C m H 2m )O] n H  (Formula I)

wherein R 1 is a C 1 -C 12 straight or branched alkyl, m is 2 to 10, n is 1 to 10, and at least one of hydrogens on any carbon may be optionally substituted with —OR 2 , Cl, or F, wherein (C m H 2m ) may be a straight or branched alkyl chain, and R 2 is H or a C 1 -C 6 straight or branched alkyl;

a terpene in an amount of 0.1 to 20% by weight;

an ethoxylated alcohol in an amount of 0.5 to 20% by weight;

a polyoxyethylene sorbitan ester in an amount of 0.5 to 20% by weight; and

a carrier fluid in an amount of 10 to 95% by weight.

2. The microemulsion composition according to claim 1 , wherein said glycol ether is selected from the group consisting of CH 3 O[CH 2 CH(CH 3 )O] 2 H, CH 3 O[CH(CH 3 )CH 2 O] 2 H, CH 3 O(CH 2 CH 2 CH 2 O) 2 H, and any combination thereof.

3. The microemulsion composition according to claim 1 , wherein said terpene is D-Limonene.

4. The microemulsion composition according to claim 1 , wherein said polyoxyethylene sorbitan ester is selected from the group consisting of polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan dioleate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan dipalmitate, polyoxyethylene sorbitan tripalmitate, and any combination thereof.

5. The microemulsion composition according to claim 4 , wherein said polyoxyethylene sorbitan ester is polyoxyethylene sorbitan trioleate.

6. The microemulsion composition according to claim 1 , wherein said carrier fluid comprises water or brine.

7. The microemulsion composition according to claim 1 , comprising a glycol ether selected from the group consisting of CH 3 O[CH 2 CH(CH 3 )O] 2 H, CH 3 O[CH(CH 3 )CH 2 O] 2 H, CH 3 O(CH 2 CH 2 CH 2 O) 2 H, and any combination thereof; D-Limonene; an ethoxylated alcohol; polyoxyethylene sorbitan trioleate; and water.

8. The microemulsion composition according to claim 1 , further comprising a scale inhibitor, wherein said scale inhibitor is selected from the group consisting of amino-tris-(methylenephosphonate) (AMP), 2-hydroxyethyl-amino-bis(methylenephosphonate) (HEABMP), ethylene-diamine-tetrakis (methylene-phosphonate) (EDTMP), tetramethylenediamine-tetrakis-(methylenephosphonate) (TDTMP), hexamethylenediamine-tetrakis(methylene-phosphonate) (HDTMP), 2-phosphonobutane-1,2,4-tricarboxylate (PBTC), hydroxyethylydene-1,1-diphosphonate (HEDP), diethylenetriamine-pentakis(methylenephosphonate) (DETPMP), acrylic acid (AA), 2-acrylamido-2-methylpropane sulfonic acid (AMPS), a copolymer of acrylamide and sodium acrylate, a copolymer made by maleic anhydride and a copolymer of acrylic acid (AA) and AMPS, 2-hydroxy phosphonoacetic acid (HPAA), sodium polycarboxylate, and any combination thereof.

9. The microemulsion composition according to claim 1 , further comprising a superwetting surfactant, wherein said superwetting surfactant is selected from the group consisting of di- or tri-siloxane glycol ethers, amine glycol ethers of the formula H 2 N(CH 2 ) x —(OCH 2 CH 2 ) y —OH, where x=2-4 and y=4-10, low volatile organic content acetylenic diols, di- or tri-siloxane glycerol polymers with a glycerol based hydrophilic head, amine glycerol polymers with a glycerol based hydrophilic head, siloxane-based surfactant, and any combination thereof.

10. The microemulsion composition according to claim 1 , further comprising a low hydrophile-lipophile balance (HLB) surfactant, wherein said low hydrophile-lipophile balance (HLB) surfactant is selected from the group consisting of sodium lauryl sulfate, naphthalene, N,N-dimethyl-9-decenamide, isopropyl alcohol, 2-butoxyethanol, cocoamidopropyl betaine, decyl glucoside, coco-glucoside, and lauryl glucoside.

11. The microemulsion composition according to claim 1 , further comprising a corrosion inhibitor, wherein said corrosion inhibitor is selected from the group consisting of isopropanol, methanol, formic acid, propanetricarboxylic acid, butanetricarboxylic acid, polyaspartic acid, lactic acid, 4-hydroxybenzoic acid, hydroxyethane-diphosphonic acid, hydroxyphosphonoacetic acid, acetaldehyde, citric acid, aluminum bisulfite, and N,N-dimethyl formaldehyde.

12. The microemulsion composition according to claim 1 , wherein the weight percentage of said carrier fluid is in the range of 50 to 90%, and said carrier fluid comprises water or brine.

13. The microemulsion composition according to claim 1 , wherein the microemulsion composition has a flash point of at least 50° C.