Nonylphenol ethoxylate-free oil dispersant formulation

Abstract

Nonylphenol ethoxylates (NPEs) have been used as surfactants in a wide variety of household products and industrial applications. Despite their effectiveness as surfactants, NPEs can accumulate in the environment and adversely affect aquatic organisms. The dispersants of the present disclosure can be used to disperse oil and/or microbes while avoiding the adverse effects of NPEs. Oil and microbial fouling is of particular concern in refinery cooling towers where the water may be contaminated with oil and microbial growth can cause cooling inefficiencies among other problems. The dispersant may include an oil dispersant comprising a C.sub.6-C.sub.20 alcohol ethoxylate, a bio-dispersant comprising a copolymer of ethylene oxide and propylene oxide, and 2-butoxyethanol. The oil dispersant, the bio-dispersant, and the 2-butoxyethanol form a dispersant solution, and the solution does not include a nonylphenol ethoxylate.

Claims

1. A dispersant, consisting of: about 20% to about 50% by weight of an oil dispersant; about 25% to about 60% by weight of a bio-dispersant, wherein the bio-dispersant is a copolymer of ethylene oxide and propylene oxide; and about 15% by weight of 2-butoxyethanol, and water, wherein the oil dispersant, the bio-dispersant, the water, and the 2-butoxyethanol form a dispersant solution, and the dispersant solution does not include a nonylphenol ethoxylate, wherein the oil dispersant is a compound of formula (I) ##STR00003## where R.sub.1 is an unsubstituted linear C.sub.6-C.sub.20 alkyl group or an unsubstituted branched C.sub.6-C.sub.20 alkyl group, and n is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15.

2. The dispersant of claim 1, wherein R.sub.1 is an unsubstituted linear C.sub.12-C.sub.16 alkyl group.

3. The dispersant of claim 1, wherein R.sub.1 is an unsubstituted linear C.sub.12-C.sub.18 alkyl group.

4. The dispersant of claim 1, wherein n is 7.

5. The dispersant of claim 1, wherein R.sub.1 is an unsubstituted linear C.sub.12-C.sub.18 alkyl group and n is 5, 6, 7, 8, 9, or 10.

6. The dispersant of claim 1, wherein the dispersant solution comprises about 25% by weight of the bio-dispersant.

7. A method of dispersing hydrocarbons and microbes, comprising: adding a dispersant solution to water that is added to a cooling tower, the dispersant solution consisting of about 20% to about 50% by weight of an oil dispersant; about 25% to about 60% by weight of a bio-dispersant that is a copolymer of ethylene oxide and propylene oxide; a solvent; and about 15% by weight of 2-butoxyethanol, wherein the dispersant solution does not include a nonylphenol ethoxylate, and the solvent is water, wherein the oil dispersant is a compound of formula (I) ##STR00004## where R.sub.1 is an unsubstituted linear C.sub.6-C.sub.20 alkyl group or an unsubstituted branched C.sub.6-C.sub.20 alkyl group, and n is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15.

8. The method of claim 7, wherein the cooling tower is a refinery cooling tower.

9. The method of claim 7, wherein R.sub.1 is an unsubstituted linear C.sub.6-C.sub.20 alkyl group.

10. The method of claim 7, wherein n is 7.

11. The method of claim 7, wherein R.sub.1 is an unsubstituted linear C.sub.12-C.sub.18 alkyl group and n is 5, 6, 7, 8, 9, or 10.

12. A dispersant, consisting of: about 25% to about 35% by weight an oil dispersant; about 15% by weight of 2-butoxyethanol, and water, wherein the oil dispersant, the 2-butoxyethanol, and water form a dispersant solution, and the dispersant solution does not include a nonylphenol ethoxylate, wherein the oil dispersant is a compound of formula (I) ##STR00005## where R.sub.1 is an unsubstituted linear C.sub.6-C.sub.20 alkyl group or an unsubstituted branched C.sub.6-C.sub.20 alkyl group, and n is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15.

13. The dispersant of claim 12, wherein the solution is stable at about room temperature for at least 24 hours.

14. The dispersant of claim 12, wherein R.sub.1 is an unsubstituted linear C.sub.12-C.sub.16 alkyl group.

15. The dispersant of claim 12, wherein R.sub.1 is an unsubstituted linear C.sub.12-C.sub.18 alkyl group and n is 5, 6, 7, 8, 9, or 10.

16. The dispersant of claim 12, wherein n is 5, 6, 7, 8, 9, or 10.

17. The dispersant of claim 12, wherein n is 7.

18. The dispersant of claim 12, wherein R.sub.1 is an unsubstituted linear C.sub.10-C.sub.20 alkyl group and n is 5, 6, 7, 8, 9, or 10.

19. A method of dispersing hydrocarbons and microbes, comprising: adding the dispersant solution of claim 12 to water that is added to a cooling tower.

Description

DETAILED DESCRIPTION

(1) Various embodiments are described below. The relationship and functioning of the various elements of the embodiments may better be understood by reference to the following detailed description. However, embodiments are not limited to those illustrated below. In certain instances details may have been omitted that are not necessary for an understanding of embodiments disclosed herein.

(2) Dispersant formulations containing NPEs may be environmentally toxic and undesirably persistent. NPEs used in industrial applications can escape into the environment via discharged water that was exposed to the dispersant formulation. Biodegradable dispersants are needed that are more environmentally compatible. Some biodegradable dispersants could replace NPEs; however, the biodegradable dispersants may not form a stable solution with the other components of the formulation. The present disclosure relates to environmentally friendly dispersants that form a stable solution.

(3) The dispersants of the present disclosure can be used to disperse oil and/or microbes. Oil and microbial fouling is of particular concern in refinery cooling towers where the water may be contaminated with oil and microbial growth can cause cooling inefficiencies among other problems.

(4) In some embodiments, a dispersant may include an oil dispersant, a bio-dispersant, and 2-butoxyethanol. The oil dispersant may include a C.sub.6-C.sub.20 alcohol ethoxylate, and the bio-dispersant may include a copolymer of ethylene oxide and propylene oxide. The oil dispersant, bio-dispersant, and 2-butoxyethanol may form a dispersant solution, and the dispersant solution does not include a nonylphenol ethoxylate.

(5) For the purposes of this disclosure, “stable” describes solutions that do not phase separate or form a cloudy suspension within 24 hours at room temperature. Stable dispersant solutions have several advantages over dispersions or multi-phase compositions. Stable solutions can be precisely metered while being added into a process to effectively control the dose of the active components. Stable solutions more rapidly mix with the medium to which it is added ensuring contact with the oil or microbes in solution or in contact with the solution.

(6) In some embodiments, the oil dispersant may be a C.sub.12-C.sub.16 alcohol polyethoxylate. In some embodiments, the oil dispersant may be a C.sub.12-C.sub.18 alcohol ethoxylate. In some embodiments, the oil dispersant may be a C.sub.12-C.sub.18 alcohol ethoxylate with 7 mol ethylene oxide. In some embodiments, the oil dispersant may be a C.sub.12-C.sub.18 alcohol ethoxylate with 6 mol ethylene oxide. In some embodiments, the oil dispersant may be a C.sub.12-C.sub.18 alcohol ethoxylate with 8 mol ethylene oxide. In some embodiments, the oil dispersant may be a C.sub.12-C.sub.18 alcohol ethoxylate with 9 mol ethylene oxide. In some embodiments, the oil dispersant may be a C.sub.12-C.sub.18 alcohol ethoxylate with 5 mol ethylene oxide.

(7) In some embodiments, the oil dispersant may be a compound of formula (I)

(8) ##STR00001##
where R.sub.1 may be an unsubstituted C.sub.6-C.sub.20 alkyl group, and n may be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15. “Alkyl” refers to a linear or branched hydrocarbon radical. In some embodiments, R.sub.1 may be an unsubstituted C.sub.8-C.sub.20 alkyl group. In some embodiments, R.sub.1 may be an unsubstituted C.sub.10-C.sub.20 alkyl group. In some embodiments, R.sub.1 may be an unsubstituted C.sub.12-C.sub.20 alkyl group. In some embodiments, R.sub.1 may be an unsubstituted C.sub.13-C.sub.20 alkyl group. In some embodiments, R.sub.1 may be an unsubstituted C.sub.14-C.sub.20 alkyl group. In some embodiments, R.sub.1 may be an unsubstituted C.sub.15-C.sub.20 alkyl group. In some embodiments, R.sub.1 may be an unsubstituted C.sub.12-C.sub.18 alkyl group.

(9) In some embodiments, R.sub.1 of formula (I) may be an unsubstituted C.sub.12-C.sub.18 alkyl group and n may be 5, 6, 7, 8, 9, or 10. In some embodiments, n may be 7. In some embodiments, n may be 6. In some embodiments, n may be 5. In some embodiments, n may be 8. In some embodiments, n may be 9. In some embodiments, n may be 10.

(10) In some embodiments, the oil dispersant may be a C.sub.6-C.sub.20 alkyl having 1 to 15 polyalkylene oxide polymer substituents. In some embodiments, the C.sub.6-C.sub.20 alkyl may have 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 polyalkylene oxide polymer substituents. In some embodiments, the polyalkylene oxide polymer may have an n of from about 1 to about 20. In some embodiments, the polyalkylene oxide polymer may have an n of from about 5 to about 10. In some embodiments, the polyalkylene oxide polymer may have an n of about 7.

(11) In some embodiments, the oil dispersant may be a C.sub.6-C.sub.20 alkyl substituted with 1 to 6 groups of formula (II)

(12) ##STR00002##
where n is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15. In some embodiments, the oil dispersant may be a C.sub.8-C.sub.18 alkyl substituted with 1 to 6 groups of formula (II). In some embodiments, the oil dispersant may be a C.sub.10-C.sub.18 alkyl substituted with 1 to 6 groups of formula (II). In some embodiments, the oil dispersant may be a C.sub.12-C.sub.16 alkyl substituted with 1 to 6 groups of formula (II). The C.sub.8-C.sub.18 alkyl, C.sub.10-C.sub.18 alkyl, or C.sub.12-C.sub.16 alkyl may be substituted with 1, 2, 3, 4, 5, or 6 groups of formula (II).

(13) In some embodiments, the oil-dispersant solution may include a nonionic surfactant. Nonionic surfactants include, but are not limited to, alkanolamides, alkyl polyglycocides, and the like, or combinations thereof. Such nonionic surfactants include one or more polyalkylene oxide polymer as a portion of the surfactant molecule. Examples of nonionic surfactants include, without limitation, benzyl-, methyl-, ethyl-, propyl-, butyl- and other like alkyl-capped polyethylene glycol ethers of fatty alcohols, and the like, or combinations thereof; polyalkylene oxide free nonionics such as, without limitation, alkyl polyglycosides, and the like, or combinations thereof; sorbitan esters, sucrose esters, sorbitan esters ethoxylates, sucrose ester ethoxylates, and the like, or combinations thereof; alkoxylated ethylene diamine; alcohol alkoxylates such as, without limitation, alcohol ethoxylates (SURFONIC® L12-6 commercially available from Huntsman), alcohol ethoxylate propoxylates, alcohol propoxylates, alcohol propoxylate ethoxylate propoxylates, alcohol ethoxylate butoxylates, and the like, or combinations thereof; polyoxyethylene glycol ethers, and the like, or combinations thereof; amine oxides, and the like, or combinations thereof; carboxylic acid esters such as, without limitation, glycerol esters, polyoxyethylene esters, ethoxylated and glycol esters of fatty acids, and the like, or combinations thereof; carboxylic amides such as, without limitation, diethanolamine condensates, monoalkanolamine condensates, polyoxyethylene fatty acid amides, and the like, or combinations thereof; and polyalkylene oxide block copolymers including an ethylene oxide/propylene oxide block copolymer such as those commercially available under the trademark PLURONIC® (BASF), and the like, or combinations thereof; other like nonionic compounds; or combinations thereof.

(14) In some embodiments, the dispersant solution may include from about 20% to about 80% by weight of the oil dispersant. In some embodiments, the amount of oil dispersant in the dispersant solution may be from about 20% to about 60% by weight, about 30% to about 60% by weight, about 40% to about 60% by weight, or about 40% to about 55% by weight. In some embodiments, the amount of oil dispersant in the dispersant solution may be about 45% by weight. In some embodiments, the amount of oil dispersant in the dispersant solution may be about 50% by weight.

(15) A representative bio-dispersant may be the commercially marketed NALCO® 7348, a nonionic ethylene oxide/propylene oxide (EO/PO) block copolymer.

(16) In some embodiments, the dispersant may include a solvent. In some embodiments, the solvent may be water.

(17) Solvents may include lower alkanols, lower alkyl ethers, glycols, aryl glycol ethers and lower alkyl glycol ethers. Examples of useful solvents include methanol, ethanol, propanol, isopropanol and butanol, isobutanol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, mixed ethylene-propylene glycol ethers, ethylene glycol phenyl ether, and propylene glycol phenyl ether. Substantially water soluble glycol ether solvents include propylene glycol methyl ether, propylene glycol propyl ether, dipropylene glycol methyl ether, tripropylene glycol methyl ether, ethylene glycol butyl ether, diethylene glycol methyl ether, diethylene glycol butyl ether, ethylene glycol dimethyl ether, ethylene glycol propyl ether, diethylene glycol ethyl ether, triethylene glycol methyl ether, triethylene glycol ethyl ether, triethylene glycol butyl ether, and others. “Substantially water soluble” solvents are defined as being infinitely or 100% soluble by weight in water at 25 degrees C. “Substantially water insoluble” glycol ether solvents include propylene glycol butyl ether, dipropylene glycol butyl ether, dipropylene glycol propyl ether, tripropylene glycol butyl ether, dipropylene glycol dimethyl ether, propylene glycol phenyl ether, ethylene glycol hexyl ether, diethylene glycol hexyl ether, ethylene glycol phenyl ether, diethylene glycol phenyl ether, and others.

(18) In some embodiments, the dispersant solution may include from about 20% to about 80% by weight of the bio-dispersant. In some embodiments, the amount of bio-dispersant in the dispersant solution may be from about 20% to about 60% by weight, about 20% to about 50% by weight, about 30% to about 60% by weight, about 35% to about 55% by weight, about 5% to about 30% by weight, about 10% to about 30% by weight, or about 20% to about 30% by weight. In some embodiments, the amount of bio-dispersant in the dispersant solution may be about 45% by weight. In some embodiments, the amount of bio-dispersant in the dispersant solution may be about 25% by weight.

(19) In certain embodiments, the dispersant solution does not include diesters or diacids. In some embodiments, C.sub.5-C.sub.11, C.sub.7-C.sub.12, or C.sub.6-C.sub.13 alcohol ethoxylates may be excluded from the dispersant solution and are not added to the process water. Other compounds that may be excluded from the dispersant solution may include alkyd resins or the condensation products of polybasic acids and polyhydric alcohols. The condensation product of a monobasic acid and a polyhydric alcohol may also be excluded from the dispersant solution in some embodiments.

(20) In other embodiments, a method of dispersing hydrocarbons and microbes is provided. The method may include adding a dispersant solution to process water used in a cooling tower. The dispersant solution may include an oil dispersant, a bio-dispersant and a solvent. The dispersant solution does not include a nonylphenol ethoxylate. The oil dispersant and the bio-dispersant may be as described above.

(21) In some embodiments, the cooling tower may be a refinery cooling tower. Oil may accumulate or deposit on surfaces of the refinery cooling tower that are in contact with the process water. The dispersant solutions of the present disclosure are particularly effective at dispersing hydrocarbon that adheres to solid surfaces.

(22) In some embodiments, the dispersant solution that is added to process water in the cooling tower may also include 2-butoxyethanol.

(23) The amount of oil dispersant or bio-dispersant in the dispersant solution that is added to the process water in the cooling tower may be as described above. In some embodiments, an effective amount of oil dispersant and/or bio-dispersant may be added so that the desired anti-fouling effect is achieved.

(24) In other embodiments, a method of cleaning filters. The method may include adding the dispersant solution comprising an oil dispersant, a bio-dispersant, and 2-butoxyethanol to the filter to remove contaminants. The filter may be a backwash filter used in a steel mill. In some embodiments, the method may include adding the dispersant solution to process water and then passing the process water through the filter.

EXAMPLES

Example 1

(25) The neat dispersant T-Det A 267NR (CAS No. 68551-12-2), which is a C.sub.12-C.sub.16 poly(1-6) ethoxylate with 7 mol ethylene oxide was cloudy and underwent separation within about 24 hours at about room temperature. The neat dispersant Dehydol LT7 (CAS No. 68213-23-0), which is a C.sub.12-C.sub.18 with 7 mol ethylene oxide, also was cloudy and underwent phase separation within about 24 hours at about room temperature. T-Det A 267NR and Dehydol LT7 are commercially available compounds.

(26) Dispersant formulations were prepared and four formulations formed stable solutions. The formulations shown in Table 1 were clear, free flowing, and stable (no phase separation) at about room temperature.

(27) TABLE-US-00001 TABLE 1 Stable Dispersant Solutions Dispersant ID Dispersant contents (% by weight) 1 45% T-Det A267NR + 45% 7348* + 10% water 2 50% Dehydol LT7 + 25% 7348 + 15% R-1171** + 10% water 3 50% Dehydol LT7 + 15% R-1171 + 35% water 4 35% T-Det A267NR + 50% water + 15% R-1171 *7348 is NALCO ® 7348, a nonionic ethylene oxide/propylene oxide (EO/PO) block copolymer **R-1171 is 2-butoxyethanol

(28) Other dispersant formulations were prepared using different proportions of Dehydol LT7, NALCO® 7348, and 2-butoxyethanol. Table 2 shows that at different proportions or temperatures the formulation can phase separate or become cloudy and viscous.

(29) TABLE-US-00002 TABLE 2 Dispersant Solutions Dispersant Dispersant contents (% by ID weight) Observations 5 75% Dehydol LT7 + 10% water + Formulation was clear at 15% R-1171** room temperature but phase separated at 4° C. 6 50% Dehydol LT7 + 25% 7348 + Slightly cloudy and 10% water viscous at room temperature *7348 is NALCO ® 7348, a nonionic ethylene oxide/propylene oxide (EO/PO) block copolymer **R-1171 is 2-butoxyethanol

Example 2

(30) Oil dispersion performance was measured using stainless steel 316 metal plates (5 cm×12 cm) with 40 mg of gas oil coated on one side of the metal plate. The weight of the clean metal plate was recorded, W.sub.0. The weight of the coated metal plate was recorded, W.sub.1. The coated plate was immersed in a test solution for about 4 hours at about room temperature (22° C.). The plate was stirred at a fixed rpm of about 750 or 1250. At the end of 4 hours the plates were removed from the respective solutions and allowed to dry for about 30 minutes. The weight of the treated plate was recorded, W.sub.2. The percentage of oil removal was calculated as (W.sub.1−W.sub.2)*100/(W.sub.1−W.sub.0).

(31) Table 3 shows the effectiveness of several compositions in removing oil from the metal plates. EO-PO refers to a block copolymer of ethylene oxide and propylene oxide.

(32) TABLE-US-00003 TABLE 3 Oil dispersant performance of various surfactants and formulations % Oil Test Application removal @ ID Composition Dose (ppm) 1250 rpm 1 45% nonylphenol ethoxylate, 45% 200 90 EO-PO block copolymer, 10% water 2 C12-C18 with 7 moles EO 150 >95 (Dehydol LT7) 3 C12-C16 poly(1-6) ethoxylate 7 150 94 moles EO (T-Det A267NR) 4 45% T-Det A267NR, 45% EO-PO 200 81 block copolymer, 10% water 5 50% Dehydol LT7, 25% EO-PO 300 83 block copolymer, 15% 2- butoxyethanol, 10% water 6 50% Dehydol LT7, 15% 2- 300 N/A butoxyethanol, 35% water 7 35% T-Det A267NR, 15% 2- 300 80 butoxyethanol, 50% water

(33) All of the compositions and methods disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. While this invention may be embodied in many different forms, there are described in detail herein specific preferred embodiments of the invention. The present disclosure is an exemplification of the principles of the invention and is not intended to limit the invention to the particular embodiments illustrated. In addition, unless expressly stated to the contrary, use of the term “a” is intended to include “at least one” or “one or more.” For example, “a device” is intended to include “at least one device” or “one or more devices.”

(34) Any ranges given either in absolute terms or in approximate terms are intended to encompass both, and any definitions used herein are intended to be clarifying and not limiting. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. Moreover, all ranges disclosed herein are to be understood to encompass any and all subranges (including all fractional and whole values) subsumed therein.

(35) Furthermore, the invention encompasses any and all possible combinations of some or all of the various embodiments described herein. It should also be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the invention and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.