Oil field desulfurizer and preparation method thereof

Abstract

The invention discloses an oil field desulfurizer and a preparation method thereof. The preparation method comprises the following steps: dissolving 1, 3-propane sultone in toluene, dropwise adding equimolar 1-methylimidazole under an ice-water bath, and heating to room temperature for reaction after dropwise adding; separating out a product after the reaction is finished, and dropwise adding equimolar concentrated sulfuric acid to obtain imidazole ionic liquid; mixing the imidazole ionic liquid with a catalytic promoter to obtain a catalyst; the preparation method comprises the following steps: adding paraformaldehyde, a triazine compound and a catalyst into a solvent, heating to 50-90 DEG C, controlling a reflux reaction for 6-9 hours, and after the reaction is finished, carrying out reduced pressure distillation to remove the solvent and separate out the catalyst, thereby obtaining the oil field desulfurizer. The desulfurizer is a modified triazine compound with a novel structure, N and lateral branch functional groups on a triazine ring of the desulfurizer can react with hydrogen sulfide, and compared with a conventional triazine desulfurizer, a plurality of desulfurization points are added, so that the sulfur capacity is greatly improved.

Description

Technical Field

[0001] The present invention relates to the field of oilfield chemistry, and particularly to an oilfield desulfurizer and a preparation method thereof. Background Art

[0002] When hydrogen sulfide is encountered in oilfield exploitation, it will pose a corrosion risk to exploitation facilities, platform facilities, and transportation pipelines. Especially during long-distance transportation, hydrogen sulfide will enter production facilities through oil pipes and submarine pipes along with the produced liquid, causing corrosion. H 2 S has a wide source and can directly come from formations, later operations, bacteria, etc. during drilling, gathering and transportation, and purification processes, making it difficult to control. Moreover, the highly toxic, strongly polluting, and strongly corrosive nature of hydrogen sulfide will cause oil and gas acidification, metal corrosion, personnel injuries, etc. Currently, the most widely used desulfurizer in offshore oilfields is triazine liquid desulfurizer. Triazine has the characteristics of high absorption efficiency, fast speed, and thorough and irreversible reaction, and can avoid the temperature usage limitations and impacts of alkanolamine desulfurizers, so it is widely used.

[0003] However, with the increasingly widespread application of triazine desulfurizer, some defects have emerged. During the continuous removal of hydrogen sulfide by triazine, the N on the triazine ring is replaced by S to form soluble thiazine compounds. As the reaction energy decays, the other two Ns on the triazine ring are difficult to react with hydrogen sulfide again, resulting in the actual desulfurization ability of triazine being lower than the theoretical value. In addition, the desulfurizer first reacts with hydrogen sulfide dissolved in the liquid phase in the process and cannot fully react with hydrogen sulfide in the gas phase. When the proportion of carbon dioxide in the acidic gas is high and the hydrogen sulfide is lower than 100 ppm, due to the disruption of the kinetic equilibrium of gas diffusion in the liquid phase, further desulfurization cannot be carried out, and it is difficult to reduce hydrogen sulfide to below 20 ppm. Therefore, the low sulfur capacity of triazine limits the application of triazine desulfurizer in the deep removal of hydrogen sulfide. Summary of the Invention

[0004] In order to solve the problems of few desulfurization sites and low sulfur capacity of the existing triazine desulfurizer, the present invention provides a high-sulfur-capacity oilfield desulfurizer and a preparation method thereof, which can be used for the deep removal of hydrogen sulfide during offshore crude oil exploitation.

[0005] In the first aspect, the present invention provides an oilfield desulfurizer, which is achieved by the following technical solutions.

[0006] An oilfield desulfurizer, the structural formula of the desulfurizer is as follows:

[0007]

[0008] Wherein, x (=2 - 3), y (=2 - 3), n (=2 - 3).

[0009] In the second aspect, the present invention provides a preparation method of an oilfield desulfurizer, which is achieved by the following technical solutions.

[0010] A preparation method of the above-mentioned oilfield desulfurizer, comprising the following steps:

[0011] S1. Dissolve 1,3-propane sultone in toluene, and dropwise add an equimolar amount of 1-methylimidazole under an ice-water bath. After the addition is complete, raise the temperature to room temperature and react for 8 to 10 hours; after the reaction is complete, separate the product, dropwise add an equimolar amount of concentrated sulfuric acid, and react at 30°C to 50°C for 3 to 4 hours to obtain an imidazolium ionic liquid;

[0012] S2. Mix and stir the imidazolium ionic liquid prepared in step S1 with a catalytic assistant in a weight ratio of 1:0.5 to 1.0 to prepare a catalyst;

[0013] S3. Add paraformaldehyde, a triazine compound, and the catalyst prepared in step S2 to a solvent. The molar ratio of paraformaldehyde to the triazine compound is 2 to 4:1. Heat to 40 to 110°C, control the reflux reaction for 6 to 9 hours. After the reaction is over, distill off the solvent under reduced pressure, separate the catalyst, and obtain the oilfield desulfurizer.

[0014] Further, in step S2, the catalytic assistant is selected from any one or a mixture of any several of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium methoxide, sodium ethoxide, pyridine, hexamethylenetetramine, tert-butylamine, tert-hexylamine, and tert-pentylamine.

[0015] Further, in step S3, the triazine compound is selected from one or more of hexahydro-1,3,5-tris(hydroxyethyl)-s-triazine (CAS: 4719-04-4) and hexahydro-1,3,5-tris(isohydroxypropyl)-s-triazine (CAS: 25254-50-6).

[0016] Further, in step S3, the solvent is selected from one or more of acetone, butanone, toluene, chloroform, carbon tetrachloride, hexane, cyclohexane, heptane, octane, acetonitrile, tetrahydrofuran, and ethylene glycol dimethyl ether.

[0017] Further, in step S3, the catalyst dosage is 0.01 to 15% of the mass of the triazine compound, preferably 0.1% to 5%.

[0018] Further, in step S3, add paraformaldehyde, the triazine compound, and the catalyst prepared in step S2 to the solvent and heat to 70 to 90°C.

[0019] This application has the following beneficial effects.

[0020] (1) The desulfurizer prepared by the present invention is a novel structurally modified triazine compound. The N on the triazine ring and the side chain functional groups can all react with hydrogen sulfide. Compared with the conventional triazine desulfurizer, it has multiple additional desulfurization sites, greatly improving the sulfur capacity;

[0021] (2) The present invention uses ionic liquid as the reaction catalyst, making the preparation reaction conditions relatively mild, and the catalyst can be recycled and reused.

[0022] (3) The preparation method of the present invention has high yield and is environmentally friendly, and is suitable for large-scale production. Detailed implementation manners

[0023] The following further illustrates the present patent application in conjunction with embodiments.

[0024] In the following embodiments, the materials used in the preparation process are not further treated without special instructions and are all purchased through commercial channels.

[0025] Example 1

[0026] A preparation method of an oilfield desulfurizer includes the following steps:

[0027] Dissolve 1,3 - propane sultone in toluene, dropwise add equimolar 1 - methylimidazole under an ice - water bath, after the addition is complete, raise the temperature to room temperature and react for 10 hours. After the reaction is complete, separate the product, dropwise add equimolar concentrated sulfuric acid, and react at 40 °C for 3 h to obtain imidazole ionic liquid. Add 2 g of sodium hydroxide and 7 g of tert - butylamine to 10 g of imidazole ionic liquid, stir evenly to obtain the catalyst. Add 219 g of hexahydro - 1,3,5 - tris(hydroxyethyl) - s - triazine, 90 g of paraformaldehyde, 80 ml of ethylene glycol dimethyl ether, and 2.2 g of catalyst to a 500 - ml reactor equipped with a condensing device, turn on the stirring, raise the temperature to 85 °C, and react for 6 hours. After the reaction is over, distill off the solvent under reduced pressure, separate the catalyst, and obtain 295 g of desulfurizer S1.

[0028] Example 2

[0029] A preparation method of an oilfield desulfurizer includes the following steps:

[0030] Dissolve 1,3 - propane sultone in toluene, dropwise add equimolar 1 - methylimidazole under an ice - water bath, after the addition is complete, raise the temperature to room temperature and react for 10 hours. After the reaction is complete, separate the product, dropwise add equimolar concentrated sulfuric acid, and react at 40 °C for 3 h to obtain imidazole ionic liquid. Add 3 g of sodium methoxide and 5 g of tert - butylamine to 10 g of imidazole ionic liquid, stir evenly to obtain the catalyst. Add 110 g of hexahydro - 1,3,5 - tris(hydroxyethyl) - s - triazine, 117 g of hexahydro - 1,3,5 - tris(hydroxypropyl) - s - triazine, 90 g of paraformaldehyde, 80 ml of cyclohexane, and 2.3 g of catalyst to a 500 - ml reactor equipped with a condensing device, turn on the stirring, raise the temperature to 85 °C, and react for 6 hours. After the reaction is over, distill off the solvent under reduced pressure, separate the catalyst, and obtain 303 g of desulfurizer S2.

[0031] Example 3

[0032] A preparation method of an oilfield desulfurizer, comprising the following steps:

[0033] Dissolve 1,3-propane sultone in toluene, dropwise add an equimolar amount of 1-methylimidazole under an ice-water bath, and after the addition is complete, raise the temperature to room temperature and react for 10 hours. After the reaction is complete, separate the product, dropwise add an equimolar amount of concentrated sulfuric acid, and react at 40 °C for 3 h to obtain an imidazolium ionic liquid. Add 2 g of sodium hydroxide and 4 g of pyridine to 10 g of the imidazolium ionic liquid, and stir evenly to obtain a catalyst. Add 153 g of hexahydro-1,3,5-tris(hydroxyethyl)-s-triazine, 70 g of hexahydro-1,3,5-tris(hydroxypropyl)-s-triazine, 90 g of paraformaldehyde, 80 ml of solvent, and 2.7 g of catalyst to a 500 ml reactor equipped with a condensation device. Turn on the stirrer, raise the temperature to 85 °C, and react for 7 hours. After the reaction is over, distill off the solvent under reduced pressure, separate the catalyst, and obtain 298 g of desulfurizer S3.

[0034] Desulfurization performance test

[0035] Perform desulfurization performance tests on the desulfurizers S1-S3 prepared in Examples 1-3 of the present invention. The specific process is as follows: Add 10 g of the desulfurizers S1-S3 and a commercially available triazine desulfurizer to a desulfurizer desulfurization performance evaluation device respectively, and introduce a mixed gas with a hydrogen sulfide concentration of 800 mg / L. 2 S / N 2 After 360 min, use a hydrogen sulfide detection tube to measure the hydrogen sulfide concentration at the outlet, and then calculate the sulfur capacity according to the formula. The results are shown in Table 1.

[0036] Sulfur capacity calculation formula:

[0037]

[0038] P: Sulfur capacity of the desulfurizer, g / g;

[0039] c 1 : Hydrogen sulfide concentration at the inlet before the desulfurization experiment, ppm;

[0040] c 2 : Hydrogen sulfide concentration at the inlet after the desulfurization experiment, ppm;

[0041] L 1 : Nitrogen flow rate, L / min;

[0042] L 2 : Hydrogen sulfide mixed gas flow rate, L / min;

[0043] t: Breakthrough time, min;

[0044] m: Desulfurizer addition amount, g.

[0045] Table 1

[0046]

[0047] As can be seen from Table 1, the sulfur capacities of the desulfurizers S1 to S3 prepared in 1-3 in the embodiments of the present application are higher than those of the commercially available desulfurizers.

[0048] The embodiments of the present specific implementation manners are all preferred embodiments of the present invention, and do not limit the protection scope of the present invention accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of the present invention shall be covered within the protection scope of the present invention.

Claims

1. An oilfield desulfurizer, characterized in that: The structural formula of the desulfurizer is as follows: Among them, x(=2~3), y(=2~3), n(=2~3).

2. A method for preparing the oilfield desulfurizer according to claim 1, characterized in that: The following steps are involved: S1. Dissolve 1,3-propane sultone in toluene, add an equal mole of 1-methylimidazole dropwise under an ice-water bath, and heat to room temperature to react for 8 to 10 hours after the addition is complete; after the reaction is complete, separate the product, add an equal mole of concentrated sulfuric acid dropwise, and react at 30°C to 50°C for 3 to 4 hours to obtain an imidazole ionic liquid; S2. The imidazolium ionic liquid prepared in step S1 and the catalyst promoter are mixed and stirred in a weight ratio of 1:0.5 to 1.0 to prepare a catalyst; S3. Add polyformaldehyde, triazine compounds and the catalyst prepared in step S2 into a solvent, wherein the molar ratio of polyformaldehyde to triazine compounds is 2 to 4:1, heat to 40 to 110°C, control the reflux reaction for 6 to 9 hours, and after the reaction is completed, distill off the solvent under reduced pressure, separate the catalyst, and obtain an oilfield desulfurizer.

3. The method for preparing an oilfield desulfurizer according to claim 2, characterized in that: In step S2, the catalyst aid is selected from any one of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium methoxide, sodium ethoxide, pyridine, hexamethylenetetramine, tert-butylamine, tert-hexylamine, and tert-amylamine, or a mixture of any of them.

4. The method for preparing an oilfield desulfurizer according to claim 2, characterized in that: In step S3, the triazine compound is selected from one or more of hexahydro-1,3,5-tris(hydroxyethyl)-s-triazine and hexahydro-1,3,5-tris(isohydroxypropyl)-s-triazine.

5. The method for preparing an oilfield desulfurizer according to claim 2, characterized in that: In step S3, the solvent is selected from one or more of acetone, butanone, toluene, chloroform, carbon tetrachloride, hexane, cyclohexane, heptane, octane, acetonitrile, tetrahydrofuran, and ethylene glycol dimethyl ether.

6. The method for preparing an oilfield desulfurizer according to claim 2, characterized in that: In step S3, the amount of catalyst added is 0.01-15% of the mass of the triazine compound.

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