USE OF COMPOSITIONS HAVING A CONTENT OF CONDENSATION PRODUCT OF 1-AMINOPROPAN-2-OL AND FORMALDEHYDE IN THE REMOVAL OF SULPHUR COMPOUNDS FROM PROCESS STREAMS

Abstract

The invention relates to the use of a composition that comprises a) one or more condensation products of 1-amino-propan-2-ol and formaldehyde and b) monoethylene glycol, wherein component a) is present in an amount from 5 to 70% by weight and component b) is present in an amount from 30 to 95% by weight, in each case based on the weight of the composition, in the removal of sulphur compounds from process streams.

Claims

1. Use of a composition that comprises a) one or more condensation products of 1-aminopropan-2-ol and formaldehyde and b) monoethylene glycol, wherein component a) is present in an amount from 5 to 70% by weight and component b) is present in an amount from 30 to 95% by weight, in each case based on the weight of the composition, in the removal of sulphur compounds from process streams.

2. Use according to claim 1, characterized in that the condensation product is produced by reacting 1-aminopropan-2-ol and formaldehyde in the molar ratio 1:0.8 to 1:1.8, preferably in the molar ratio 1:0.9 to 1:1.6.

3. Use according to claim 2, characterized in that the component a) is 3,3-methylenebis[5-methyloxazolidine].

4. Use according to claim 3, characterized in that component a) is present in an amount from 20 to 60% by weight, and component b) is present in an amount from 40 to 80% by weight, wherein preferably component a) is present in an amount from 30 to 50% by weight, and component b) is present in an amount from 50 to 70% by weight, wherein, in particular component a) is present in an amount of about 40% by weight and component b) is present in an amount of about 60% by weight.

5. Use according to claim 4, characterized in that the composition comprises less than 10% by weight of water, preferably less than 5% by weight of water, in particular less than 2% by weight of water, such as less than 1% by weight of water.

6. Use according to claim 2, characterized in that component a) is N,N,N-tris(2-hydroxypropyl)hexahydrotriazine.

7. Use according to claim 6, characterized in that the composition comprises 2 to 25% by weight of water, preferably 5 to 20% by weight of water, in particular 10 to 15% by weight of water, such as 12% by weight of water.

8. Use according to claim 6, characterized in that component a) is present in an amount from 35 to 60% by weight and component b) is present in an amount from 30 to 50% by weight, wherein preferably component a) is present in an amount from 40 to 55% by weight and component b) is present in an amount from 35 to 45% by weight, wherein, in particular component a) is present in an amount of about 48% by weight and component b) is present in an amount of about 40% by weight.

9. Use according to claim 1, characterized in that the composition does not comprise a dialkylhydroxylamine of the formula RRNOH, wherein R and R independently of one another are selected from linear, branched and cyclic C.sub.1 to C.sub.10 alkyl groups.

10. Use according to claim 1, characterized in that the composition does not comprise an additive selected from urea, urea derivatives, amino acids, guanidine and guanidine derivatives.

11. Use according to claim 1, characterized in that the process stream is selected from liquid and gaseous process streams.

12. Use according to claim 1, characterized in that the process stream contains at most 40% by weight of water, preferably at most 35% by weight of water, particularly preferably at most 30% by weight of water, such as at most 25% by weight of water, or at most 20% by weight, or at most 15% by weight, for instance at most 10% by weight, or at most 5% by weight, for example at most 1% by weight, of water.

13. Use according to claim 1, characterized in that the process stream is a hydrocarbon stream.

14. Use according to claim 1, characterized in that the sulphur compound is selected from hydrogen sulphide, inorganic and organic sulphides, mercaptans and mercaptides, wherein the composition is preferably used in the removal of hydrogen sulphide from process streams.

15. Method for removing one or more sulphur compounds from a process stream, in which the process stream that contains the sulphur compound or sulphur compounds is contacted with a composition that comprises a) one or more condensation products of 1-aminopropan-2-ol and formaldehyde and b) monoethylene glycol, wherein component a) is present in an amount from 15 to 70% by weight and component b) is present in an amount from 30 to 85% by weight, in each case based on the weight of the composition.

16. Use of a) one or more condensation products of 1-aminopropan-2-ol and formaldehyde and b) monoethylene glycol, wherein the weight ratio used of a):b) is in the range from 5:95 to 70:30, in the removal of sulphur compounds from process streams.

Description

EXAMPLES

[0034] 1. Condensation Products Used

[0035] Grotan? OX:

[0036] The reaction product of isopropanolamine and paraformaldehyde (91%) is formed in the molar ratio 2:3. In this case 3,3-methylenebis(5-methyloxazolidine) is formed. The reaction water and the water from the paraformaldehyde are distilled off.

[0037] Grotan? WS:

[0038] The reaction product is formed from isopropanolamine and paraformaldehyde (91%) in the molar ratio 3:3 (1:1). This forms ?,?,?-trimethyl-1,3,5-triazine-1,3,5-(2H,4H,6H)-triethanol (N,N,N-tris(2-hydroxypropyl)hexahydrotriazine, TTT). The reaction water and the water from the paraformaldehyde remain in the product. The TTT content is about 80% by weight.

[0039] 2. Method: Determination of the Sulphide Concentration (Based on IP 570, Determination of Hydrogen Sulphide in Mineral Oils) [0040] Action of the differing sulphur capturing agents on the sample at various temperatures and for differing times [0041] Dilution of the sample with alkylbenzene in order to arrive at the linear working range of the analysis system [0042] Injection of the sample under investigation (including sulphur capturing agent) into the analysis system [0043] Addition of acid (2M H.sub.3PO.sub.4 in water) and optionally heating the analytical sample in the analysis system [0044] Quantitative expulsion of the resultant hydrogen sulphide in the analysis system by means of air and transfer of the hydrogen sulphide to an electrochemical measuring electrode in the analysis apparatus [0045] The hydrogen sulphide generates, at the electrochemical measurement electrode, a measurement signal that is proportional to the respective hydrogen sulphide amount [0046] By means of evaluation software, the resultant peak area (composed of measured signal intensity against time) is determined and converted to a sulphide content, on the basis of a calibration line

[0047] 3. Study of Various Formaldehyde Condensation Products, Glycols and Mixtures Thereof

[0048] In order to show the advantages of the compositions used according to the invention, a test was made as to what action various compositions have on the removal of H.sub.2S in C.sub.10-13 alkyl benzene (sulphide concentration 200 ppm). The samples were heated for this purpose to 50? C. and the compositions were used in an amount in each case of 1000 ppm, wherein in the table hereinafter, for the mixtures of condensation product and glycol (monoethylene glycol and propylene glycol) in each case the weight ratio is stated. The results in the case of percentage reduction of H.sub.2S content after exposure for 2 or 24 hours are given in Tab. 1.

TABLE-US-00001 TABLE 1 No. Composition 2 h 24 h 1* Monoethylene glycol 2.3% 5.8% 2* Grotan? OX 7.9% 17.8% 3* Grotan? OX + Monoethylene 9.7% 24.5% glycol (9:1) 4* Grotan? OX + Monoethylene 18.7% glycol (8:2) 5 Grotan? OX + Monoethylene 21.9% 82.6% glycol (6:4) 6 Grotan? OX + Monoethylene 23.3% 86.1% glycol (1:1) 7 Grotan? OX + Monoethylene 25.4% 88.0% glycol (4:6) 8 Grotan? OX + Monoethylene 21.5% 93.6% glycol (3:7) 9 Grotan? OX + Monoethylene 22.3% 97.5% glycol (2:8) 10 Grotan? OX + Monoethylene 14.6% 99.4% glycol (1:9) 11* Grotan? OX + Propylene 13.8% 34.0% glycol (4:6) 12* Grotan? WS 14.0% 72.4% 13 Grotan? WS + Monoethylene 25.0% 88.9% glycol (6:4) *Comparison Experiment not carried out

[0049] The results verify that monoethylene glycol and the condensation products of 1-aminopropan-2-ol and formaldehyde (Grotan? OX and Groton? WS) in each case alone reduce the H.sub.2S content only insufficiently, and more precisely not only for the exposure time of 2 h, but also for the exposure time of 24 h (comparative experiments 1, 2 and 12). The same applies to compositions consisting of Grotan? OX and monoethylene glycol in the weight ratios 9:1 and 8:2 (comparative experiments 3 and 4), that is to say having a small fraction of monoethylene glycol, and also to compositions consisting of Grotan? OX and propylene glycol (comparative experiment 11).

[0050] In contrast, the compositions according to the invention consisting of i) condensation product of 1-aminopropan-2-ol and formaldehyde (Grotan? OX or Grotan? WS) and ii) monoethylene glycol surprisingly act considerably better when the content of monoethylene glycol is higher than 20% by weight (experiments 5 to 10 and 13). In the case of compositions according to the invention consisting of i) Grotan? OX and ii) monoethylene glycol, for an exposure time of only 2 h, it is shown that a composition consisting of Grotan? OX and monoethylene glycol in the weight ratio 4:6 (experiment 7) already acts well (reducing the H.sub.2S content by 25.4%), and for an exposure time of 24 h, the reduction is even 88%. In the case of the markedly longer exposure time of 24 h, in contrast, a mixture consisting of Grotan? OX and monoethylene glycol in the weight ratio 1:9 (experiment 10) acts excellently (reduction by 99.4%).

[0051] 4. Particularly Preferred Composition

[0052] For production of the particularly preferred composition consisting of a) 40% by weight of 3,3-methylenebis-[5-methyloxazolidine] and b) 60% by weight of monoethylene glycol, monoethylene glycol is charged and Grotan? OX is added. After brief stirring, a clear, colourless solution is obtained having the following properties (Tab. 2).

TABLE-US-00002 TABLE 2 Appearance clear, colourless solution Hazen colour number 11 Density at 20? C., g/ml 1.108 Refraction at 20? C. 1.457 Cleavable HCHO, % 17.9

[0053] The storage stability of this composition was studied by storing samples for 1 month at 25? C. or 40? C. in PE bottles (Tab. 3):

TABLE-US-00003 TABLE 3 After 1 month of storage at 25? C. 40? C. Appearance clear, slightly light yellow yellowish Hazen colour number 29 70 Density at 20? C., g/ml 1.108 1.108 Refraction at 20? C. 1.457 1.457 Cleavable HCHO, % 17.7 17.8 Reduction of H.sub.2S content, 2 h, % 26.0 27.9 Reduction of H.sub.2S content, 24 h, % 87.5 87.4

[0054] The results in Tab. 3 verify that this particularly preferred composition has not lost the activity in the reduction of H.sub.2S content even after storage for one month at an elevated temperature of 40? C.