Preparation method of triazine desulfurizer

Abstract

The invention discloses a preparation method of a triazine desulfurizer. The method comprises the following steps: 1, adding primary amine into a three-neck round-bottom flask, and stirring; 2, slowly dropwise adding a formaldehyde aqueous solution in a stirring state, carrying out a constant-temperature reaction, and carrying out reduced pressure distillation purification to obtain a triazine desulfurizer main body; and 3, uniformly stirring and mixing the triazine desulfurizer main body, peracetic acid, polyethylene glycol and ethylenediamine to obtain the triazine desulfurizer. The triazine desulfurizing agent is prepared by compounding the triazine desulfurizing agent main body with the peracetic acid, the polyethylene glycol and the ethylenediamine, so that hydrogen sulfide in a sulfur-containing system is effectively removed, organic sulfur benzothiophene substances which are difficult to remove are converted into sulfoxide and sulfone which are easy to remove, and the compatibility of the triazine desulfurizing agent and the sulfur-containing system is improved; therefore, the desulfurization rate is greatly improved, the sulfur content in a sulfur-containing system is remarkably reduced, and the method is suitable for the field of desulfurization.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental protection, and particularly relates to a method for preparing a triazine desulfurizing agent. Background Art

[0002] Hydrogen sulfide is widely present in natural gas and biogas, and has a pungent and foul smell. It is not only highly toxic to the human body, but also flammable and explosive, and is extremely easy to corrode metals and clog pipelines. Even if the exhaust gas and natural gas discharged by factories contain a small amount of hydrogen sulfide, it will cause great pollution to the environment. Sometimes, a lot of resources are wasted because of the presence of low concentrations of hydrogen sulfide. All sulfur-containing compounds have the possibility of generating hydrogen sulfide through various reactions. The hydrogen sulfide in industrial waste gas mainly comes from refineries, natural gas purification plants, coal gas purification plants, smelters, tanneries, nitrogen fertilizer plants, pesticide plants, etc., but in terms of quantity, it is mainly sulfur-containing gases in refineries, natural gas purification plants, coal gas purification plants and synthetic nitrogen fertilizer raw gas in nitrogen fertilizer plants. Over the years, researchers at home and abroad have conducted a lot of research on the desulfurization of sulfur-containing gases such as natural gas, coalbed methane and biogas.

[0003] In traditional desulfurization processes, using solid desulfurizers to remove sulfides is a common method. Commonly used ones include zinc oxide, activated carbon, molecular sieves, etc. However, due to the small specific surface area of ​​these materials and poor adsorption performance, the desulfurization efficiency is low. In addition, since solid desulfurizers are usually not recyclable, the overall cost remains high. In recent years, liquid desulfurizers represented by alcoholamines and sulfoneamines have become an emerging technology. This type of desulfurizer has the advantage of low cost, most of which can be regenerated and are suitable for desulfurization treatment in high-concentration hydrogen sulfide environments. However, they also have the problem of low desulfurization efficiency, high equipment requirements, and large initial investment. At the same time, residual substances may cause greater environmental pollution.

[0004] For natural gas purification plants, the H2S concentration is generally not high, mostly below 1000mg / L. Combined with the harsh on-site production conditions, it is more economical and practical to use non-renewable liquid desulfurizers that are affordable and have strong absorption capacity. Among them, triazine compounds, as a widely used liquid desulfurizer, especially water-soluble triazine, stand out for its fast reaction speed, high-efficiency desulfurization ability and convenient operation. It can be directly injected into the pipeline for desulfurization operations. At the same time, it has the advantages of low cost, easy acquisition and easy treatment of residues, which is very suitable for the desulfurization tasks of oil fields and gas fields with low H2S content. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a method for preparing a triazine desulfurizer in view of the above-mentioned deficiencies of the prior art. The method compounds the triazine desulfurizer main body with peracetic acid, polyethylene glycol and ethylenediamine to form a triazine desulfurizer, which can effectively remove hydrogen sulfide in a sulfur-containing system, and convert organic sulfur benzothiophene substances that are difficult to remove into sulfoxides and sulfones that are easy to remove, and increases the compatibility of the triazine desulfurizer with the sulfur-containing system, thereby greatly improving the desulfurization rate, significantly reducing the sulfur content in the sulfur-containing system, and solving the problem of low desulfurization efficiency in the prior art.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for preparing a triazine desulfurization agent, characterized in that the method comprises the following steps:

[0007] Step 1: Place a three-necked round-bottom flask in an ice bath thermostat, and connect a condenser, a liquid dropper, and an electric stirring device, then add the primary amine into the three-necked round-bottom flask, and turn on the electric stirring device for stirring;

[0008] Step 2: Open the liquid dropper in the stirring state in step 1, and then slowly drop the formaldehyde aqueous solution, after the dropwise addition is completed, perform a constant temperature reaction, and then perform vacuum distillation and purification to obtain the main body of the triazine desulfurizer;

[0009] Step 3: Mix the triazine desulfurization agent obtained in step 2, peracetic acid, polyethylene glycol and ethylenediamine, and then stir and mix them to obtain a triazine desulfurization agent.

[0010] The above-mentioned method for preparing a triazine desulfurizer is characterized in that the stirring speed in step 1 is 600 rpm.

[0011] The above-mentioned method for preparing a triazine desulfurizing agent is characterized in that the primary amine in step 1 is ethanolamine, methylamine or methoxypropylamine. More preferably, the primary amine is ethanolamine.

[0012] The above-mentioned method for preparing a triazine desulfurizer is characterized in that the dripping speed of the formaldehyde aqueous solution in step 2 is 1 mL / min. Since the isothermal reaction between primary amine and formaldehyde releases a large amount of heat, and the anti-product will decompose at 75°C, the reaction is carried out under electric stirring to dissipate heat in time, and the dripping speed of the formaldehyde aqueous solution is controlled to control the reaction speed, the temperature is controlled at 50°C, and the temperature change is observed at all times. If the temperature rises too fast, the dripping speed of the formaldehyde aqueous solution needs to be slowed down or the dripping needs to be stopped, and the ice bath is used to cool down.

[0013] The above-mentioned method for preparing a triazine desulfurizer is characterized in that the mass concentration of the formaldehyde aqueous solution in step 2 is 35% to 37%, and the molar ratio of the primary amine to the formaldehyde in the formaldehyde aqueous solution in step 1 is 0.8 to 1.2:1.

[0014] The above-mentioned method for preparing a triazine desulfurizing agent is characterized in that the temperature of the isothermal reaction in step 2 is 30° C. to 50° C., and the reaction time is 2 h to 4 h.

[0015] The above-mentioned method for preparing a triazine desulfurizer is characterized in that, in step three, the triazine desulfurizer body comprises 85 to 100 parts by mass, 8 to 12 parts by mass peracetic acid, 1 to 3 parts by mass polyethylene glycol, and 1 to 3 parts by mass ethylenediamine.

[0016] The above-mentioned method for preparing a triazine desulfurizing agent is characterized in that the stirring temperature in step 3 is 30° C. to 50° C. and the stirring time is 30 minutes.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] 1. The present invention first uses primary amine and formaldehyde as raw materials to prepare a triazine desulfurizer body, then compound the triazine desulfurizer body with peracetic acid, polyethylene glycol and ethylenediamine to form a triazine desulfurizer, and utilizes the triazine desulfurizer body and ethylenediamine to remove hydrogen sulfide in a sulfur-containing system, and peracetic acid helps to improve the desulfurization rate of the triazine desulfurizer body and ethylenediamine, and the peracetic acid can also act on organic sulfur benzothiophene substances that are difficult to remove in a sulfur-containing system such as oxidized crude oil, so that benzothiophene is converted into sulfoxide and sulfone that are easy to remove, thereby greatly improving the desulfurization rate and significantly reducing the sulfur content in the sulfur-containing system, especially in the oxidized crude oil.

[0019] 2. The present invention adds a nonionic surfactant polyethylene glycol to the triazine desulfurizer system, utilizes the nonionic surfactant polyethylene glycol to reduce the surface tension of the system, further increases the compatibility of the triazine desulfurizer with the sulfur-containing system such as oxidized crude oil, enables the triazine desulfurizer to achieve homogeneous desulfurization in the oxidized crude oil, and further improves the desulfurization rate.

[0020] The technical solution of the present invention is further described in detail below through embodiments. DETAILED DESCRIPTION

[0021] Example 1

[0022] This embodiment includes the following steps:

[0023] Step 1: Place a 250 mL three-necked round-bottom flask in an ice bath thermostat, and connect a condenser, a liquid dropper, and an electric stirring device, then add ethanolamine to the three-necked round-bottom flask, turn on the electric stirring device, and adjust the speed to 600 rpm for stirring;

[0024] Step 2: in the stirring state in step 1, open the liquid dropper, and then slowly drop a formaldehyde aqueous solution with a mass concentration of 35%, and the molar ratio of the primary amine to the formaldehyde in the formaldehyde aqueous solution in step 1 is 0.8:1, and the drop rate of the formaldehyde aqueous solution is controlled to be 1 mL / min. After the dropwise addition is completed, a constant temperature reaction is carried out at 30° C. for 2 hours, and then a reduced pressure distillation is performed for purification to obtain a triazine desulfurization agent body;

[0025] Step 3: Mix 85 parts of the triazine desulfurization agent obtained in step 2, 8 parts of peracetic acid, 1 part of polyethylene glycol, and 1 part of ethylenediamine by mass, and then stir and mix at 30° C. for 30 minutes to obtain a triazine desulfurization agent.

[0026] Example 2

[0027] This embodiment includes the following steps:

[0028] Step 1: Place a 250 mL three-necked round-bottom flask in an ice bath thermostat, and connect a condenser, a liquid dropper, and an electric stirring device, then add ethanolamine to the three-necked round-bottom flask, turn on the electric stirring device, and adjust the speed to 600 rpm for stirring;

[0029] Step 2: in the stirring state in step 1, open the liquid dropper, and then slowly drop a formaldehyde aqueous solution with a mass concentration of 35%, and the molar ratio of the primary amine to the formaldehyde in the formaldehyde aqueous solution in step 1 is 1:1, and the drop rate of the formaldehyde aqueous solution is controlled to be 1 mL / min. After the dropwise addition is completed, a constant temperature reaction is carried out at 40° C. for 3 hours, and then a reduced pressure distillation is performed for purification to obtain a triazine desulfurization agent body;

[0030] Step 3: Mix 90 parts of the triazine desulfurization agent obtained in step 2, 10 parts of peracetic acid, 2 parts of polyethylene glycol, and 2 parts of ethylenediamine by mass, and then stir and mix at 40° C. for 30 minutes to obtain a triazine desulfurization agent.

[0031] Example 3

[0032] This embodiment includes the following steps:

[0033] Step 1: Place a 250 mL three-necked round-bottom flask in an ice bath thermostat, and connect a condenser, a liquid dropper, and an electric stirring device, then add ethanolamine to the three-necked round-bottom flask, turn on the electric stirring device, and adjust the speed to 600 rpm for stirring;

[0034] Step 2: in the stirring state in step 1, open the liquid dropper, and then slowly drop a formaldehyde aqueous solution with a mass concentration of 35%, and the molar ratio of the primary amine to the formaldehyde in the formaldehyde aqueous solution in step 1 is 1.2:1, and the drop rate of the formaldehyde aqueous solution is controlled to be 1 mL / min. After the dropwise addition is completed, a constant temperature reaction is carried out at 50° C. for 4 hours, and then a reduced pressure distillation is performed for purification to obtain a triazine desulfurization agent body;

[0035] Step 3: Mix 100 parts of the triazine desulfurization agent obtained in step 2, 12 parts of peracetic acid, 3 parts of polyethylene glycol, and 3 parts of ethylenediamine by mass, and then stir and mix at 50° C. for 30 minutes to obtain a triazine desulfurization agent.

[0036] Example 4

[0037] The difference between this embodiment and embodiment 1 is that ethanolamine is replaced by methylamine in step 1.

[0038] Example 5

[0039] The difference between this embodiment and embodiment 1 is that in step 1, ethanolamine is replaced by methoxypropylamine.

[0040] Comparative Example 1

[0041] The difference between this embodiment and embodiment 1 is that no peracetic acid is added in step 3.

[0042] Comparative Example 2

[0043] The difference between this embodiment and embodiment 1 is that ethylenediamine is not added in step 3.

[0044] The desulfurization performance of the triazine desulfurizer prepared in Examples 1 to 5 of the present invention and Comparative Examples 1 to 2 was tested. The specific process was as follows: 10 mL of triazine desulfurizer was loaded into a U-shaped tube with a support and 100 ppm of hydrogen sulfide standard gas was introduced. The flow rate of hydrogen sulfide standard gas was 0.6 L / min. The TYBX31C pump-suction gas detector produced by Shanghai Tangyi Electronic Technology Co., Ltd. was used to detect the hydrogen sulfide concentration at the outlet of the U-shaped tube and start timing. When the timing started, the hydrogen sulfide concentration in the outlet gas flow of the U-shaped tube was 100 ppm, and the remaining balance gas was nitrogen. When the hydrogen sulfide concentration at the outlet reached 1 ppm, the timing was stopped. The time used in the process of starting and stopping the timing was the penetration time. The penetration time and the capacity of the adsorbent to absorb hydrogen sulfide were calculated. The results are shown in Table 1 below.

[0045] The calculation formula of sulfur capacity is:

[0046]

[0047] Table 1 Desulfurization performance of triazine desulfurizers prepared in Examples 1 to 5 of the present invention and Comparative Examples 1 to 2

[0048]

[0049] As can be seen from Table 1, the triazine desulfurizer prepared in Examples 1 to 5 of the present invention has a high hydrogen sulfide absorption capacity, indicating that the present invention compounded the triazine desulfurizer body with peracetic acid, polyethylene glycol, and ethylenediamine to form a triazine desulfurizer, used the triazine desulfurizer body and ethylenediamine to remove hydrogen sulfide in the sulfur-containing system, and used peracetic acid to activate the nitrogen atoms on the triazine desulfurizer body, so that the nitrogen atoms on the triazine ring body are more likely to react with hydrogen sulfide by nucleophilic substitution, thereby improving the desulfurization rate, and compounding the nonionic surfactant polyethylene glycol increases the compatibility of the triazine desulfurizer with the sulfur-containing system, so that the triazine desulfurizer achieves homogeneous desulfurization in the oxidized crude oil, further improving the desulfurization rate. At the same time, compared with Comparative Examples 1 to 2, since no peracetic acid is added in Comparative Example 1 and no ethylenediamine is added in Comparative Example 2, the desulfurization rate and desulfurization performance of the corresponding triazine desulfurizer are significantly reduced.

[0050] Compared with Examples 4 to 5, Examples 1 to 3 of the present invention use ethanolamine as a raw material to prepare the triazine desulfurizer body, and introduce hydroxyl groups into the triazine desulfurizer body, so that the hydrogen sulfide capacity of the triazine desulfurizer is higher, and the compatibility with the sulfur-containing system is better, thereby improving the desulfurization rate; whereas in Examples 4 to 5, since hydroxyl groups are not introduced into the triazine desulfurizer body, the compatibility of the triazine desulfurizer with the sulfur-containing substances in the sulfur-containing system is poor, and the desulfurization rate decreases.

[0051] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent change made to the above embodiment according to the technical essence of the invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing a triazine desulfurizing agent, characterized in that: The method comprises the following steps: Step 1: Place a three-necked round-bottom flask in an ice bath thermostat, and connect a condenser, a liquid dropper, and an electric stirring device, then add the primary amine into the three-necked round-bottom flask, and turn on the electric stirring device for stirring; Step 2: in the stirring state in step 1, open the liquid dropper, and then slowly drop the formaldehyde aqueous solution, after the dropwise addition is completed, perform a constant temperature reaction, and then perform vacuum distillation and purification to obtain the main body of the triazine desulfurizer; Step 3: Mix the triazine desulfurization agent obtained in step 2, peracetic acid, polyethylene glycol and ethylenediamine, and then stir and mix them to obtain a triazine desulfurization agent.

2. The method for preparing a triazine desulfurization agent according to claim 1, characterized in that: The stirring speed in step 1 is 600 rpm.

3. The method for preparing a triazine desulfurizing agent according to claim 1, characterized in that: The primary amine in step 1 is ethanolamine, methylamine or methoxypropylamine.

4. The method for preparing a triazine desulfurizing agent according to claim 1, characterized in that: The dropping speed of the formaldehyde aqueous solution in step 2 is 1 mL / min.

5. The method for preparing a triazine desulfurizing agent according to claim 1, characterized in that: The mass concentration of the formaldehyde aqueous solution in step 2 is 35% to 37%, and the molar ratio of the primary amine to the formaldehyde in the formaldehyde aqueous solution in step 1 is 0.8 to 1.2:

1.

6. The method for preparing a triazine desulfurizing agent according to claim 1, characterized in that: The temperature of the isothermal reaction in step 2 is 30° C. to 50° C., and the reaction time is 2 h to 4 h.

7. The method for preparing a triazine desulfurizing agent according to claim 1, characterized in that: In step 3, the triazine desulfurization agent main body is 85-100 parts, peracetic acid is 8-12 parts, polyethylene glycol is 1-3 parts, and ethylenediamine is 1-3 parts by mass.

8. The method for preparing a triazine desulfurizing agent according to claim 1, characterized in that: The stirring temperature in step 3 is 30°C to 50°C, and the stirring time is 30 minutes.

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