REMOVAL OF ORGANIC DEPOSITS

Abstract

Disclosed is a cleaning composition for removing organic deposits. The cleaning composition comprises a salt of the monoconjugate base of an aliphatic phosphate monoester and a salt of the conjugate base of an aliphatic phosphate diester in a hydrocarbon-based solvent system. The cleaning composition has been found to be effective in use together with an aqueous phase in mobilizing or dissolving organic deposits, without forming persistent emulsions, suspensions or the like. Accordingly following its use phase separation between a hydrocarbon-based phase and an aqueous phase occurs following a settling period.

Claims

1.-49. (canceled)

50. A cleaning composition for removing organic deposits, the cleaning composition comprising a first salt that is a salt of a conjugate base of an aliphatic phosphate diester; a second salt that is a salt of a monoconjugate base of an aliphatic phosphate monoester; and a hydrocarbon-based solvent system.

51. The cleaning composition of claim 50 wherein the first and second salts are present in approximately equimolar amounts.

52. The cleaning composition of claim 50 wherein the cleaning composition comprises about 0.1 weight % to 80 weight % of the combined first and second salts.

53. The cleaning composition of claim 50 wherein the first salt and/or the second salt comprises an alkali metal salt, an ammonium salt, an alkylammonium salt or a hydroxyalkylammonium salt.

54. The cleaning composition of claim 50 wherein the first salt has structure (A) and the second salt has structure (B), ##STR00003## wherein R.sub.1, R.sub.2 and R.sub.3 are independently C.sub.4-C.sub.12 aliphatic groups; n and m are independently 1 or 2; and X and Y are independently monovalent or divalent cations.

55. The cleaning composition of claim 54, wherein X and Y are independently selected from Na.sup.+, NH.sub.4.sup.+, and HOCH.sub.2CH.sub.2NH.sub.3.sup.+.

56. A cleaning formulation comprising the cleaning composition of claim 50 and water, wherein the ratio by volume of the cleaning composition to the water is between 1:1 and 1:5.

57. A method of removing organic deposits from an article, comprising providing a cleaning composition, the composition comprising a first salt that is the salt of the conjugate base of an aliphatic phosphate diester, and a second salt that is the salt of the monoconjugate base of an aliphatic phosphate monoester, a hydrocarbon-based solvent system; and applying the cleaning composition to an article comprising an organic deposit.

58. The method of claim 57, further comprising applying water to the article.

59. The method of claim 58, comprising applying the cleaning composition to the article before applying the water to the article.

60. The method of claim 58, comprising combining the cleaning composition and the water and applying the combination to the article.

61. The method of claim 58 further comprising separating an aqueous phase and a hydrocarbon-based phase after applying the cleaning composition to the article.

62. The method of claim 61 wherein the separating comprises allowing a settling period of 1 to 1000 hours.

63. The method of claim 57 wherein the applying is mixing the cleaning composition with a fluid flowing through a fluid flow system.

64. The method of claim 63 wherein the mixing is mixing about 0.01% to 2% of the cleaning composition by volume of the fluid flowing through the fluid flow system.

65. The method of claim 63 further comprising separating an aqueous phase and a hydrocarbon-based phase after the mixing.

66. A method of preparing a cleaning composition, the method comprising: providing a first solution comprising an aliphatic phosphate monoester and an aliphatic phosphate diester; adding a base to the first solution in an amount sufficient to form a second solution comprising a salt of the monoconjugate base of the aliphatic phosphate monoester; and a salt of the conjugate base of the aliphatic phosphate diester; and adding at least one hydrocarbon solvent to the second solution to form the cleaning composition.

67. The method of claim 66 wherein the base is a basic solution.

68. The method of claim 66 wherein the base comprises ammonia.

69. The method of claim 57 further comprising adding water to the cleaning composition to form a cleaning formulation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0150] Non-limiting example embodiments will now be described with reference to the following figures in which:

[0151] FIG. 1 shows tabulated results for Test A conducted on examples 1-18 (see Table 1 below), in which the wt % of wax ball dissolution is plotted, together with the relative proportions of oil and water phases observed.

[0152] FIG. 2 shows photographs of sample bottles following Test B conducted on examples 1-18 (see Table 1 below).

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0153] Phosphate esters were obtained by reacting appropriate alcohols with phosphorus pentoxide (in a 3:1 molar ratio) to give an approximately equimolar mixture of the corresponding alkyl mono- and di-alkyl esters of phosphoric acid.

[0154] This mixture was used as such to prepare a mixture of salts. Salts of such alkyl phosphate mono- and di-esters were produced by reacting with either ammonia, sodium hydroxide, or monoethanolamine in a mixture of solvents using conventional methods.

[0155] Details of example cleaning compositions 1-18 are presented in Table 1.

TABLE-US-00001 TABLE 1 [00002] Phosphate esters (PEs) Component (wt-%) Ehtylene Heavy glycol aromatic monobutyl A R1 R2 PEs Kerosene naphtha ether Water 1 NH.sub.4 2-Ethylhexyl R1 and H, ratio 1/1 10.6 80.0 0 6.5 2.9 2 Na 2-Ethylhexyl R1 and H, ratio 1/1 10.8 79.3 0 6.5 3.4 3 H.sub.3NC.sub.2H.sub.4OH 2-Ethylhexyl R1 and H, ratio 1/1 12.2 80.0 0 6.5 1.3 4 NH.sub.4 iso-Tridecyl R1 and H, ratio 1/1 10.5 80.6 0 6.5 2.4 5 Na iso-Tridecyl R1 and H, ratio 1/1 10.6 80.0 0 6.5 2.9 6 H.sub.3NC.sub.2H.sub.4OH iso-Tridecyl R1 and H, ratio 1/1 11.6 80.0 0 6.5 1.9 7 NH.sub.4 n-Butyl R1 and H, ratio 1/1 10.9 79.2 0 6.5 3.4 8 Na n-Butyl R1 and H, ratio 1/1 11.1 77.5 0 6.5 4.9 9 H.sub.3NC.sub.2H.sub.4OH n-Butyl R1 and H, ratio 1/1 13.2 80.0 0 6.5 0.3 10 NH.sub.4 2-Ethylhexyl R1 and H, ratio 1/1 10.6 0 80 6.5 2.9 11 NH.sub.4 2-Ethylhexyl R1 and H, ratio 1/1 10.6 0 0 86.5 2.9 12 NH.sub.4 2-Ethylhexyl R1 and H, ratio 1/1 10.6 0 0 6.5 82.9 13 NH.sub.4 2-Ethylhexyl R1 and NH4, ratio 1/1 10.9 80.0 0 6.5 2.6 14 Na 2-Ethylhexyl R1 and Na, ratio 1/1 11.3 76.8 0 6.5 5.4 15 NH.sub.4 iso-Tridecyl R1 and NH4, ratio 1/1 10.6 80.0 0 6.5 2.9 16 Na iso-Tridecyl R1 and Na, ratio 1/1 10.9 79.0 0 6.5 3.6 17 NH.sub.4 n-Butyl R1 and NH4, ratio 1/1 11.4 79.2 0 6.5 2.9 18 Na n-Butyl R1 and Na, ratio 1/1 11.8 76.9 0 6.5 4.8

[0156] Examples 1-18 were evaluated for cleaning efficiency (Test A) and emulsion forming tendency (Test B) as follows.

[0157] Test A: Wax Ball Dissolution Test

[0158] An amount of 2.50 grams of a waxy deposit isolated from a crude oil production facility was shaped into a ball. The ball was placed in a 100 ml bottle and 40 ml of tap water and 10 ml of an example product formulation (Table 1) was added. The bottle was closed and shaken one time by hand, whereafter the wax ball was located at the oil-water interface. The bottle was stored for 48 hours at 20 C.

[0159] Following the storage period, the appearance of the liquid(s) was recorded. Results are summarised in Table 2 and FIG. 1.

[0160] Each sample was assessed for the presence of separate a separate hydrocarbon-based phase (Oil phase, table 2) and an aqueous phase (Water phase, table 2). In addition, each phase was assessed for turbidity; i.e. whether clear, hazy (i.e. partially clear) or milky.

[0161] In addition, following separation (by decanting) of the liquid portion, the undissolved remainder of the wax ball dried for 3 hours at 95 C. on a petri dish.

[0162] The weight of the dried wax was then determined, and the weight percentage of dissolution of the wax ball was calculated as follows: wt %=(remaining weight (g)/2.50)100%. Results are presented in Table 2 and FIG. 1.

TABLE-US-00002 TABLE 2 Wax Example dissolved Appearance liquids 48 h # (Wt %) Oil phase Water phase 1 37.2 Clear Clear 2 15.6 Clear Clear 3 19.6 Clear Clear 4 2.4 Milky Milky 5 3.2 Hazy Milky 6 3.2 Milky Milky 7 16.0 Clear Hazy 8 17.1 Clear Clear 9 26.8 Clear Hazy 10 39.2 Clear Clear 11 3.2 One phase = clear 12 4.0 One phase = Milky 13 12.0 Hazy Clear 14 8.0 Clear Clear 15 3.2 Milky Milky 16 2.8 Hazy Milky 17 7.2 Hazy Hazy 18 5.6 Hazy Hazy

[0163] Example B: Removal of Crude Oil

[0164] An amount of 10.0 grams of crude oil sample with 20 API gravity were weighed into each of 9 100 ml bottles at 20 C.

[0165] Each bottle was capped and shaken by hand to in order to completely coat the inside of the bottle with crude oil. Each bottle was then immediately opened and inverted to allow the crude oil to drain for 10 minutes.

[0166] 10 gram of each of examples 1-9 (see Table 1) was added to the bottles. The bottles were capped and shaken by hand, opened and inverted to allow the contents to drain for 10 minutes.

[0167] Once drained, 15 grams of tap water was add to each of the bottles. The bottles were again capped and shaken by hand, opened and inverted and allowed to drain.

[0168] The appearance of the inside of the bottles was photographically recorded as presented in FIG. 2. The appearance of the water phase after 24 hours was visually recorded and is presented in Table 3.

TABLE-US-00003 TABLE 3 Example # Appearance water phase 24 h 1 Clear 2 Clear 3 Clear 4 Milky 5 Milky 6 Milky 7 Hazy 8 Clear 9 Hazy

[0169] Discussion

[0170] Results of Test A (Table 2 and FIG. 1)

[0171] Examples 1-3, 8, 10 and 14 resulted in clearly separated oil and water phases.

[0172] Examples 1-3, 7-10, 13-14 and 17-18 resulted in significant dissolution of the wax ball; above around 5 wt %

[0173] The largest amount of wax dissolved and lowest emulsion forming tendency, as indicated by clear oil and water phases obtained, was observed for Examples 1-3 and 10 with A=NH.sub.4, Na and H.sub.3NCH.sub.2CH.sub.2OH, R.sub.1=2-ethylhexyl, and R.sub.2=2-ethylhexyl/H (1/1).

[0174] The largest amount of wax was dissolved for Examples 1 and 10 with A=NH.sub.4, R.sub.1=2-ethylhexyl, and R.sub.2=2-ethylhexyl/H (1/1).

[0175] Comparatively low percentages of the wax ball was dissolved by examples 4-6 and 15-16; each of which were based on salts of C13 aliphatic (iso-tridecyl) phosphate mono- and di-esters.

[0176] Example 11 was based on an organic solvent system (the major solvent being ethylene glycol monobutyl ether, with around 3 wt % water as co-solvent). Example 12 was based on an aqueous solvent system (water with around 6 wt % ethylene glycol monobutyl ether). Neither of these examples 11-12 comprised a hydrocarbon-based solvent system. Examples 11 and 12 also resulted in low percentage wax ball dissolution, in test A.

[0177] Results Example B (Table 3 and FIG. 2)

[0178] The results obtained for Examples 1-3 clearly demonstrate that best cleaning efficiency combined with lowest emulsion forming tendency, as indicated by clear water phase obtained, was observed for Example 1-3 with A=NH.sub.4, Na and H.sub.3NCH.sub.2CH.sub.2OH, R.sub.1=2-ethylhexyl, and R.sub.2=2-ethylhexyl/H (1/1).

[0179] It is noted that for the lighter crude samples (as compared to the wall ball samples of test A) good results are also obtained for example 7, comprising salts of n-butyl phosphate mono-and di-esters.

[0180] Basicity

[0181] The compositions of Examples 1-8 have a pH (measured at 5 wt % in water) of approximately 5-6, and have each been neutralized to their intermediate equivalence points (as determined by standard titration methods).

[0182] The compositions of Examples 13-18 have a pH (measured at 5 wt % in water) of approximately 7 and have been neutralized to around the upper equivalence point.

[0183] In Table 2 (and FIG. 1) the performance of the compositions at their intermediate equivalence point can be compared against the corresponding compositions neutralized to the upper equivalence point.

[0184] Specifically, by comparing Example 1 vs. Example13, Example 2 vs. Example 14, Example 7 vs. Example 17 and Example 8 vs. Example 18 shows that the best performance is obtained for Examples 1, 2, 7 and 8, all of which have been neutralized to the intermediate equivalence point. Whereas, equivalent compositions 13, 14, 17 and 18 which have a higher basicity (upper equivalence points) have markedly worse performance.

[0185] Examples 4, 5, 15 and 16 demonstrate poor performance regardless of basicity.

[0186] Example 19. Procedure for the preparation of the concentrated formulation for Example 1 from ammonia gas

[0187] In a 500 ml glass reactor equipped with a stirrer and gas inlet tube 211.5 gram of 2-ethylhexyl phosphate ester (monoester: diester mole ratio=1:1), 46.5 gram of ethylene glycol monobutyl ether and 28.5 gram of deionized water where brought together. To this stirred mixture 13.5 gram of ammonia gas was bubbled in through the gas inlet tube which was positioned below the liquid level of the stirred mixture. The ammonia gas was introduced over a period of 2 hours while maintaining a temperature of 20 to 30 C. by external cooling. The product was a clear liquid with a pH of 4.8 (measured as a 5 wt % solution in deionized water).

[0188] Example 20: Preparation of the composition of Example 1 from Example 19

[0189] To 14.2 gram of product from Example 19 was added 80.0 gram of kerosene, 4.3 gram of ethylene glycol monobutyl ether and 1.5 gram of deionized water. The components were mixed well to give the composition of Example 1 as a clear liquid with a pH of 5.5 (measured as a 5 wt % solution in deionized water).