METHOD OF SCAVENGING ACID SULFIDE SPECIES

Abstract

A method of scavenging acid sulfide species from an industrial or environmental material, the method comprising contacting the material with: (a) propenal and/or maleimide and/or ethyl-2-chloroacetoacetate; and (b) a base.

Claims

1. A method of scavenging acid sulfide species from an industrial or environmental material, the method comprising contacting the material with: (a) propenal and/or maleimide and/or ethyl-2-chloroacetoacetate; and (b) a base.

2. The method according to claim 1 wherein component (a) comprises propenal and/or maleimide.

3. The method according to claim 1 wherein component (a) comprises propenal.

4. The method according to claim 1 wherein component (b) is selected from: (i) amino compounds; (ii) phosphorus containing bases; and (iii) inorganic bases.

5. The method according to claim 1 wherein component (b) is selected from: a triazine of formula (VA): ##STR00029## in which each of R.sup.a, R.sup.b and R.sup.c is an alkyl, hydroxyalkyl or alkoxyalkyl group; methylene bis(5-methyloxazolidine); an amine of formula R.sup.1R.sup.2R.sup.3N in which each of R.sup.1, R.sup.2 and R.sup.3 is independently hydrogen or an alkyl group which is optionally substituted with a group selected from hydroxy, alkoxy, amino, alkylamino, dialkylamino or aryl, provided that at least one of R.sup.1, R.sup.2 and R.sup.3 is not hydrogen; a trialkyl phosphine; and an alkali metal or ammonium hydroxide

6. The method according to claim 1 wherein component (b) comprises an amino compound selected from monoethanolamine triazine (MEA triazine), monomethylamine triazine (MMA triazine), methoxypropylamine triazine (MOPA triazine), methylene bis(5-methyloxazolidine), monoethanolamine, triethylamine, methoxypropylamine, cyclohexylamine, triethanolamine, 3-phenylpropylamine, diethanolamine, 2-aminopropylamine, tributylamine, N-(2-hydroxyethyl)ethylenediamine, N.sup.1,N.sup.1-bis(2-aminoethyl)-1,2-ethanediamine, 1-(2-aminoethyl)piperazine, 4-(2-aminoethyl)phenol, 2-amino-2-(hydroxymethyl)propane-1,3-diol, 4-(2-aminoethyl)morpholine, 2-(2-aminoethoxy)ethanol, dimethylaminopropylamine, ethylene diamine and 1,8-diazabicyclo(5.4.0)undec-7-ene (DBU).

7. The method according to claim 1 wherein component (a) is selected from MEA triazine, MMA triazine, MOPA triazine, monoethanolamine, methoxypropylamine, triethylamine, 2-aminoethoxyethanol, methylene bis(5-methyloxazolidine) and N-(2-hydroxyethyl) ethylene diamine.

8. The method according to claim 1 wherein component (a) is selected from monomethylamino triazine, monoethanolamine triazine and methoxypropylamine triazine.

9. The method according to claim 1 wherein component (a) and component (b) are added to the industrial or environmental material in a single composition or in separate compositions.

10. The method according to claim 9 wherein component (a) and component (b) are added to the industrial or environmental material in separate compositions.

11. The method according to claim 1 wherein the industrial or environmental material is selected from crude oil, produced water, petroleum refinery liquids, coke, asphalt or bitumen, used fracturing fluids, used water-flooding fluids, brines, geothermal fluids or sour gas.

12. The method according to claim 1 wherein the industrial or environmental material comprises water.

13. The method according to claim 1 wherein the acidic sulfide species is hydrogen sulfide.

14. A product for scavenging acid sulfide species, the product comprising: (a) a first composition comprising propenal and/or maleimide and/or ethyl-2-chloroacetoacetate; and (b) a second composition comprising a base.

15. The product according to claim 14 which further comprises (c) a scale inhibitor and/or a corrosion inhibitor.

16. The product according to claim 14 which further comprises one or more further components selected from biocides, friction reducers, drag reducing agents, surfactants, foaming agents, carbon dioxide scavengers, oxygen scavengers and metal scavengers

17. (canceled)

18. The product according to claim 14 wherein the first composition comprising propenal and/or maleimide and/or ethyl-2-chloroacetoacetate is an aqueous or organic composition.

19. The product according to claim 14 wherein the second composition comprising a base is an aqueous composition.

20. The product according to claim 14 which scavenges and retains hydrogen sulfide at temperatures in excess of 140° C.

21. (canceled)

22. The method according to claim 1 wherein the first composition comprising propenal and/or maleimide and/or ethyl-2-chloroacetoacetate is an aqueous or organic composition.

23. The method according to claim 1 wherein the second composition comprising a base is an aqueous composition.

24. The method according to claim 1 which scavenges and retains hydrogen sulfide at temperatures in excess of 140° C.

Description

EXAMPLE 1

[0227] The thermal stability of various combinations of propenal and/or maleimide (a) and a base (b) as hydrogen sulfide scavengers was tested according to the following procedure:

[0228] 2 ml of a stock solution containing 0.6 mg/ml of Na.sub.2S in water was added to water (8 ml) in a reaction vessel with stirrer bar. The vessel was tightly sealed and hydrogen sulfide was generated in situ by injecting HCl (0.07 ml of 0.5M solution, 2 molar equivalents relative to Na.sub.2S). Thus the solution contained approximately 50 mg/I of hydrogen sulfide. 5 molar equivalents relative to Na.sub.2S of propenal or maleimide or ethyl-2-chloroacetoacetate (a) and 5 molar equivalents relative to Na.sub.2S of a base (b) were then injected and the mixture heated to 75° C. for 30 minutes with stirring. After cooling to room temperature the scavenged mixture was poured into a transparent pressure vessel. An H.sub.2S indicator was placed inside the pressure vessel (not touching the liquid) and the system sealed. The pressure vessel was then heated (5° C. per minute) to a maximum temperature of 180° C. or until the indicator showed the presence of H.sub.2S in the gas phase. Results are shown in Table 1.

[0229] Examples 1 to 12 are of the invention. Example 13 is comparative.

TABLE-US-00001 TABLE 1 Propenal/ maleimide/ Temperature ethyl-2- at which Ex- chloroaceto- H.sub.2S is mple Base acetate Solvent re-released 1 MEAtriazine None Water 100° C. 2 None Propenal Water Does not fully scavenge after 30 minutes 3 MEAtriazine Propenal Water >180° C. 4 MEAtriazine Maleimide Water 170° C. 5 Monoethanolamine None Water Does not fully scavenge afer 30 minutes 6 Monoethanolamine Propenal Water >180° C. 7 Monoethanolamine Maleimide Water >180° C. 8 Triethylamine Propenal Water >180° C. 9 Triethylamine Maleimide Water 155° C. 10 PMe.sub.3 Propenal Water >180° C. 11 NaOH Propenal Water >180° C. 12 MEAtriazine ethyl-2- water 150° C. chloroaceto- acetate 13 MEAtriazine glyoxal water 95° C.

EXAMPLE 2

[0230] The thermal stability of a variety of amines in combination with propenal was tested according to the procedure of Example 1. The results are provided in Table 2:

TABLE-US-00002 TABLE 2 Tempera- ture at which Exam- H.sub.2S is ple Amine Media released 14 None Water Did not scavenge (sulfides remains) 15 [00013] Water   180° C. 16 [00014] Water   180 ° C. 17 [00015] Water >180° C. 18 [00016] Water   180° C. 19 [00017] Water   180° C. 20 [00018] Water   180° C. 21 [00019] Water   180° C. 22 [00020] Water   180° C. 23 [00021] Water   180° C. 24 [00022] Water >180° C. 25 [00023] Water >180° C. 26 [00024] Water   180° C. 27 [00025] Water >180° C. 28 [00026] Water   180° C. 29 [00027] Water >180° C. 30 [00028] Water   180° C.

EXAMPLE 3

[0231] A combination of MEA triazine and propenal or MEA triazine and ethyl-2-chloroacetoacetate was incubated for 30 minutes at 75° C. in a variety of brines using a procedure analogous to that described in Example 1. The temperature at which hydrogen sulfide is re-released was measured.

[0232] The results are shown in Table 3.

TABLE-US-00003 TABLE 3 Temperature at Scavenger Brine (% which H.sub.2S is Example COmbination dissolved salt) re-released 1B MEA triazine Deionised water 100° C. 2B MEA triazine and Deionised water >180° C. 2B Pro penal Deionised water >180° C. 3B MEA triazine and Bakken (25%) >180° C. Propenal 4B MEA triazine and IOC (11%) >180° C. Propenal 5B MEA triazine and Marcellus (8%) >180° C. Propenal 6B MEA triazine and Eagle Ford (2%) >180° C. Propenal 7B MEA triazine and ethyl- Deionised water 150° C. 2-chloroacetoacetate 8B MEA triazine and ethyl- Bakken (25%) 150° C. 2-chloroacetoacetate 9B MEA triazine and ethyl- IOC (11%) 150° C. 2-chloroacetoacetate 10B MEA triazine and ethyl- Marcellus (8%) 150° C. 2-chloroacetoacetate 11B MEA triazine and ethyl- Eagel Ford (2%) 150° C. 2-chloroacetoacetate

EXAMPLE 4

[0233] The rate at which compounds and combinations of compounds scavenge hydrogen sulfide was measured as follows:

[0234] 2 ml of a stock solution containing 0.6 mg/ml of Na.sub.2S in water was added to water (18 ml) in a reaction vessel with stirrer bar. The vessel was tightly sealed and hydrogen sulfide was generated in situ by injecting HCl (0.07 ml of 0.5M solution, 2 molar equivalents relative to Na.sub.2S). Thus the solution contained approximately 25 mg/I of hydrogen sulfide. The mixture was heated to 30° C. with stirring and an aliquot (0.3 ml) was removed via syringe and the liquid-phase H.sub.2S content determined using a colourimetric test. This is the time=0 reading. 5 molar equivalents relative to Na.sub.2S of propenal or maleimide (a) and 5 molar equivalents relative to Na.sub.2S of a base (b) were then injected and the scavenging monitored by testing aliquots of the mixture at set time intervals (typically 1, 5, 10 and 20 minutes).

[0235] Table 4 and FIG. 1 to show how the rate of combination of acrolein and MEA triazine scavenge hydrogen sulfide at much greater rate than MEA triazine alone.

TABLE-US-00004 TABLE 4 Average concentration of H.sub.2S (mg/L) after period of: Component 0 1 5 10 15 20 30 FIG. (b) Component (a) min min min min min min min number MEA triazine none 20.6 20.3 19.7 15.5 10.9 8.1 1 MEA triazine maleimide 22.3 0.1 0.2 0.2 0.2 2 None propenal 24.7 22.9 22.9 22.1 21.2 20.9 3 MEA triazine propenal 24.2 0.3 0.0 0.0 0.0 4 ethanolamine propenal 23.1 11.9 4.5 2.0 0.9 5 MBO None 19.1 16.8 13.3 9.3 7.1 5.7 6 MBO Propenal 16.4 0.0 0.0 0.0 0.0 7 MEA triazine Ethyl-2- 23.5 0.4 0.4 0.4 0.6 8 chloroacetoacetate NaOH Propenal 22.0 7.4 0.7 0.2 0.1 9 MBO is methylene bis(5-methyloxazolidine)

EXAMPLE 5

[0236] A range of scavengers and scavenger combinations were contacted in excess amounts with an aqueous composition comprising hydrogen sulfide at different temperatures. The results are shown in table 5:

TABLE-US-00005 TABLE 5 Molar H.sub.2C Solids remaining after ratio (to 1 detected scavenging: Scavenger eq H.sub.2C at end ? at 30° C.? at 80° C.? at 180° C.? MEA 5 yes no no no triazine MEA 2 yes no no yes triazine A 5 no no no no A 2 no no no no B 5 no no no no B 2 no no no no C 5 no no no no C 2 no no no no

[0237] Scavenger A contained 1 part MEA triazine and 2 parts maleimide.

[0238] Scavenger B contained 1 part MEA triazine and 4 parts maleimide.

[0239] Scavenger C contained 1 part MEA triazine and 2.7 parts ethyl-2-chloroacetoacetate.