Use of compositions having a content of 3,3′-methylenebis(5-methyloxazolidine) in the removal of sulphur compounds from process streams

Abstract

The invention relates to the use of a composition comprising a) 3,3-methylenebis(5-methyl oxazolidine) and b) one or more additives selected from among (i) urea, urea derivatives, amino acids, guanidine and guanidine derivatives and (ii) 1,2-diols in the removal of sulphur compounds from process streams. The composition is preferably used in the removal of hydrogen sulphide from process streams.

Claims

1. A method for removing sulphur compounds from liquid or gaseous process streams comprising a step of contacting the liquid or gaseous process stream with a composition comprising: a) 3,3-methylenebis(5-methyloxazolidine) and b) urea.

2. The method according to claim 1, characterized in that the composition is in the form of a concentrate and comprises from 60 to 99% by weight of 3,3-methylenebis(5-methyloxazolidine).

3. The method according to claim 2, characterized in that the composition is in the form of a concentrate and comprises from 70 to 97% by weight of 3,3-methylenebis(5-methyloxazolidine).

4. The method according to claim 3, characterized in that the composition is in the form of a concentrate and comprises from 80 to 92% by weight of 3,3-methylenebis(5-methyloxazolidine).

5. The method according to claim 1, characterized in that the composition is in the form of a concentrate and comprises from 1 to 20% by weight of urea.

6. The method according to claim 5, characterized in that the composition is in the form of a concentrate and comprises from 2 to 14% by weight of urea.

7. The method according to claim 6, characterized in that the composition is in the form of a concentrate and comprises from 2.5 to 8% by weight of urea.

8. The method according to claim 1, characterized in that the composition further comprises one or more 1,2-diols.

9. The method according to claim 8, characterized in that the composition is in the form of a concentrate and comprises from 1 to 25% by weight of 1,2-diol.

10. The method according to claim 9, characterized in that the composition is in the form of a concentrate and comprises from 3 to 20% by weight of 1,2-diol.

11. The method according to claim 10, characterized in that the composition is in the form of a concentrate and comprises from 5 to 15% by weight of 1,2-diol.

12. The method according to claim 8, characterized in that the 1,2-diol is selected from the group consisting of ethylene glycol, propylene glycol and mixtures thereof.

13. The method according to claim 12, characterized in that the 1,2-diol is ethylene glycol.

14. The method according to claim 1, characterized in that the composition further comprises c) N,N-dialkyl hydroxylamine of the formula RRNOH, where R and R are selected independently from among linear, branched and cyclic C.sub.1-C.sub.10-alkyl groups.

15. The method according to claim 14, characterized in that the N,N-dialkyl hydroxylamine is N,N-diethyl hydroxylamine.

16. The method according to claim 1, characterized in that the process stream contains not more than 40% by weight of water.

17. The method according to claim 1, characterized in that the process stream is a hydrocarbon stream.

18. The method according to claim 1, characterized in that the sulphur compound is selected from the group consisting of hydrogen sulphide, inorganic and organic sulphides, mercaptans and mercaptides.

19. The method according to claim 18, characterized in that the sulphur compound is hydrogen sulphide.

20. A method for removing sulphur compounds from process streams comprising a step of contacting the process stream with a composition comprising: a) 3,3-methylenebis(5-methyloxazolidine) and b) urea, wherein the process streams are selected from the group consisting of hydrocarbon streams, petroleum, crude oil, mineral oil, heating oil, diesel fuel, bitumen, distillation residues, drilling fluids and wastewater.

Description

DESCRIPTION OF PREFERRED EMBODIMENTS

(1) In a first aspect, the invention thus provides for the use of a composition comprising:

(2) a) 3,3-methylenebis(5-methyl oxazolidine) and

(3) b) one or more additives selected from among: (i) urea, urea derivatives, amino acids, guanidine and guanidine derivatives and (ii) 1,2-diols,
in the removal of sulphur compounds from process streams.

(4) The composition used according to the invention is preferably in the form of a concentrate and comprises from 60 to 99% by weight of 3,3-methylenebis(5-methyl oxazolidine), preferably from 70 to 97% by weight, in particular from 80 to 92% by weight.

(5) In a first preferred embodiment, the composition comprises:

(6) b) one or more additives selected from among urea, urea derivatives, amino acids, guanidine and guanidine derivatives. Examples of such additives are glycoluril, tetramethylolglycoluril, dimethylhydantoin, dimethyloldimethylhydantoin, dimethylolurea, tetramethylolurea, imidazolidinylurea and diazolidinylurea.

(7) The composition particularly preferably comprises b) urea. Here, preference is given to the composition being in the form of a concentrate and comprising b) from 1 to 20% by weight of urea, preferably from 2 to 14% by weight, in particular from 2.5 to 8% by weight, for example from 3 to 6% by weight, of urea.

(8) In a second preferred embodiment, a composition comprising b) one or more 1,2-diols is used. In this embodiment, preference is given to the composition being in the form of a concentrate and comprising b) from 1 to 25% by weight of 1,2-diol, preferably from 3 to 20% by weight, in particular from 5 to 15% by weight, of 1,2-diol. Preferred 1,2-diols used according to the invention are selected from among ethylene glycol, propyleneglycol and mixtures thereof, with component b) preferably being ethylene glycol.

(9) In a third preferred embodiment, the composition used according to the invention comprises b) at least one component (i) and at least one component (ii). In this embodiment, preference is again given to the composition being in the form of a concentrate and comprising b) (i) from 1 to 20% by weight of urea, preferably from 2 to 14% by weight, in particular from 2.5 to 8% by weight, for example from 3 to 6% by weight of urea. It is further preferred in this embodiment that the composition comprises b) (ii) from 1 to 25% by weight of 1,2-diol, preferably from 3 to 20% by weight, in articular from 5 to 15% by weight, of 1,2-diol.

(10) Particular preference is thus given according to the invention to using compositions comprising:

(11) a) from 60 to 99% by weight of 3,3-methylenebis(5-methyloxazolidine), (preferably from 70 to 97% by weight, in particular from 80 to 92% by weight, of 3,3-methylenebis(5-methyl oxazolidine)),

(12) b) (i) from 1 to 20% by weight of urea (preferably from 2 to 14% by weight, in particular from 2.5 to 8% by weight, for example from 3 to 6% by weight, of urea) and

(13) b) (ii) from 1 to 25% by weight of 1,2-diol (preferably from 3 to 20% by weight, in particular from 5 to 15% by weight, of 1,2-diol).

(14) Apart from the compulsory components a) 3,3-methylenebis(5-methyl oxazolidine) and b) one or more of the additives mentioned, the composition can further comprise c) N,N-dialkyl hydroxylamine of the formula RRNOH, where R and R are selected independently from among linear, branched and cyclic C.sub.1-C.sub.10-alkyl groups. A preferred N,N-dialkyl hydroxylamine is N, N-diethyl hydroxylamine.

(15) Process streams treated according to the invention are, for example, liquid and gaseous process streams.

(16) Exemplary process streams contain no more than 40% by weight of water, preferably not more than 35% by weight of water, particularly preferably not more than 30% by weight of water, for example not more than 25% by weight or not more than 20% by weight or not more than 15% by weight, for example not more than 10% by weight or not more than 5% by weight, for example not more than 1% by weight, of water.

(17) Fields of use are, inter alia, biogas plants, petroleum and natural gas extraction, processing, storage and transport of fossil energy carriers and the removal of H.sub.2S liberated by sulphate-reducing bacteria under anaerobic conditions. Examples of H.sub.2S-containing streams or products are petroleum, crude oil, mineral oil, heating oil, diesel fuel, bitumen, distillation residues, drilling fluids and wastewater. Particular preference is given to the use according to the invention of the compositions in process streams which are hydrocarbon streams.

(18) In a second embodiment, the invention relates to a process for removing one or more sulphur compounds from a process stream, wherein the process stream containing the sulphur compound or sulphur compounds is brought into contact with a composition comprising a) 3,3-methylenebis(5-methyl oxazolidine) and b) one or more additives selected from among (i) urea, urea derivatives, amino acids, guanidine and guanidine derivatives and (ii) 1,2-diols.

(19) The use is preferably at elevated temperature (for example 50 C. or above, e.g. 70 C. or above, 90 C. or even 150 C. or above). Subsequent liberation of H.sub.2S advantageously does not occur to the same extent as in the case of the sole use of 3,3-methylenebis(5-methyl oxazolidine). The compositions used according to the invention are better suited for binding the inherent H.sub.2S which is gradually formed subsequently during prolonged hot storage than is 3,3-methylenebis(5-methyl oxazolidine) alone.

(20) The constituents according to the invention can be introduced individually into the H.sub.2S-containing process streams, either within a short time interval or at different points in time. Surprisingly, there is reduced formation of troublesome insoluble deposits or precipitates, sometimes such precipitates are even dissolved. Compositions used according to the invention also have a very good short-term and in particular long-term action. Rapid and efficient lowering of the H.sub.2S content is achieved at short contact times.

(21) The advantages of the invention can be seen, in particular, from the following examples. Percentages are by weight, unless indicated otherwise.

Examples

(22) Composition OX (Comparison):

(23) The reaction product of isopropanolamine and paraformaldehyde (91% strength) in a molar ratio of 2:3 is formed. 3,3-Methylenebis(5-methyl oxazolidine) is formed here. The water of reaction and the water from the paraformaldehyde are distilled off.

(24) Composition OK (According to the Invention):

(25) The reaction product of isopropanolamine and paraformaldehyde (91% strength) in a molar ratio of 2:3 is formed. 3,3-Methylenebis(5-methyl oxazolidine) is formed here. The water of reaction and the water from the paraformaldehyde are distilled off. Urea and ethylene glycol are added (the mixture contains about 4.6% by weight of urea and about 9.5% by weight of ethylene glycol).

(26) Method of determining the sulphide concentration (based on IP 570, Determination of hydrogen sulphide in mineral oils) Contacting of the various sulphur-scavenging agents with the sample at various temperatures and for different times Dilution of the sample with alkylbenzene in order to bring it into the linear working range of the analytical system Injection of the test sample (including sulphur-scavenging agent) into the analytical system Addition of acid (2M H.sub.3PO.sub.4 in water) and optionally heating of the analytical sample in the analytical system Quantitative driving-off of the resulting hydrogen sulphide in the analytical system by means of air and transfer of the hydrogen sulphide to an electrochemical measuring electrode in the analytical instrument The hydrogen sulphide produces a measurement signal which is proportional to the respective amount of hydrogen sulphide at the electrochemical measuring electrode. The peak area formed (made up of measurement signal intensity versus time) is determined by means of evaluation software and converted into a sulphide content on the basis of a calibration line.
a) H.sub.2S in C.sub.10-13-alkylbenzene (sulphide concentration 200 ppm), 20 C., 2 h

(27) TABLE-US-00001 Lowering of the sulphide content % 1000 ppm OX 8.8 (comparison) 1000 ppm OK 11.6 (invention)
b) H.sub.2S in C.sub.10-13-alkylbenzene (sulphide concentration 100 ppm), 50 C.

(28) TABLE-US-00002 Lowering of the sulphide content % 1 h 2 h 3 h 1000 ppm OX 6.7 6.2 3.8 (comparison) 1000 ppm OK 9.6 10.2 11.4 (invention)
c) H.sub.2S in C.sub.10-13-alkylbenzene (sulphide concentration 200 ppm), 50 C., 2 h

(29) TABLE-US-00003 Lowering of the sulphide content % 1000 ppm OX 10.0 (comparison) 1000 ppm OK 15.4 (invention)

(30) These examples demonstrate that compositions used according to the invention not only decrease the sulphide content better than does 3,3-methylenebis(5-methyloxazolidine) alone, but that this improved effect is even more pronounced at an elevated use temperature.

(31) While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations as fall within the spirit and broad scope of the appended claims. The present invention may suitably comprise, consist or consist essentially of the elements disclosed and may be practiced in the absence of an element not disclosed. Furthermore, if there is language referring to order, such as first and second, it should be understood in an exemplary sense and not in a limiting sense. For example, it can be recognized by those skilled in the art that certain steps can be combined into a single step.

(32) The singular forms a, an and the include plural referents, unless the context clearly dictates otherwise.

(33) Comprising in a claim is an open transitional term which means the subsequently identified claim elements are a nonexclusive listing (i.e., anything else may be additionally included and remain within the scope of comprising). Comprising as used herein may be replaced by the more limited transitional terms consisting essentially of and consisting of unless otherwise indicated herein.

(34) Providing in a claim is defined to mean furnishing, supplying, making available, or preparing something. The step may be performed by any actor in the absence of express language in the claim to the contrary.

(35) Optional or optionally means that the subsequently described event or circumstances may or may not occur. The description includes instances where the event or circumstance occurs and instances where it does not occur.

(36) Ranges may be expressed herein as from about one particular value, and/or to about another particular value. When such a range is expressed, it is to be understood that another embodiment is from the one particular value and/or to the other particular value, along with all combinations within said range.

(37) All references identified herein are each hereby incorporated by reference into this application in their entireties, as well as for the specific information for which each is cited.