Organic amine composite desulfurizer and preparation method thereof, and desulfurization method of fuel gas

Abstract

The invention provides an organic amine composite desulfurizer and a preparation method thereof, and a desulfurization method of fuel gas, the organic amine composite desulfurizer comprises the following raw materials by mass: 35-65% of s-triazine derivative, 0.1-2.0% of organic strong base, 1.0-5.0% of inorganic salt, and the balance of water; wherein the structural formula of the s-triazine derivative is shown as a formula I, and in the # imgabs0 # formula I, R1, R2 and R3 are respectively and independently selected from C1-C4 alkyl groups, C1-C4 hydroxyalkyl groups, C1-C4 alkoxy groups and C1-C4 alkenyl groups. According to the organic amine composite desulfurizer, the s-triazine derivative can be selectively subjected to nucleophilic substitution reaction with H2S under the condition of high pH value and does not react with CO2, and meanwhile, the nucleophilic substitution reaction product can continue to react with H2S, so that the desulfurization efficiency, selectivity and sulfur capacity of the composite desulfurizer are effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of gas desulfurization, and in particular to an organic amine composite desulfurizer and a preparation method thereof, and a fuel gas desulfurization method. Background Art

[0002] Currently, the energy consumption of heating furnaces in production units such as atmospheric and vacuum, catalytic cracking, and catalytic hydrogenation in refining and chemical enterprises is relatively high, and there is still significant room for improvement in the thermal efficiency of heating furnaces in various refining and chemical enterprises. The main factors affecting the thermal efficiency of heating furnaces are exhaust gas temperature, air oxygen content, excess air coefficient, and heat loss. Heat loss caused by high exhaust gas temperature accounts for approximately 70-80% of the total heat loss of the heating furnace. The current average exhaust gas temperature of heating furnaces is 120-160°C. The high total sulfur content in the fuel gas is a key factor restricting the efficiency and carbon reduction of the heating furnaces throughout the plant. This is because the sulfides in the fuel gas are burned to form sulfur dioxide, which then forms sulfur trioxide. During the exhaust process, sulfur trioxide combines with water vapor to form sulfuric acid. To avoid sulfuric acid dew point corrosion, the exhaust gas temperature must be controlled above the sulfuric acid dew point corrosion temperature. As a result, the excess heat in the flue gas cannot be recovered and reused, and the thermal efficiency of the heating furnace is reduced.

[0003] Sulfides in fuel gas include hydrogen sulfide, mercaptans, sulfides, carbonyl sulfide, and carbon disulfide, with hydrogen sulfide being the primary component. Furthermore, fuel gas contains 0.1-3.0% carbon dioxide, which can easily co-absorb with hydrogen sulfide and other compounds, hindering deep desulfurization effectiveness. Therefore, selective deep desulfurization of fuel gas is crucial for improving heating furnace efficiency, but it also presents significant challenges. Preventing co-absorption of carbon dioxide is a key technical challenge.

[0004] CN108097015A discloses an amine liquid desulfurization absorbent, its preparation method, and application. The desulfurization absorbent comprises an N-methyldiethanolamine (MDEA) aqueous solution and a modified metal-organic framework material. It can solve the foaming problem existing in the existing selective desulfurization process technology using amine liquid MDEA. However, the sulfur capacity of the desulfurization absorbent in this technology is relatively low, and the amine liquid needs to be frequently regenerated, resulting in high energy consumption of the treatment process technology.

[0005] CN111013368B discloses a reaction system, absorption liquid, and method for simultaneously absorbing multiple acidic gases. By adding N-methyldiethanolamine (MDEA), diethylenetriamine (DETA), and a small amount of piperazine to the absorption liquid to form a composite absorbent, the system can simultaneously absorb sulfur-containing gases and carbon-containing gases, thereby improving the absorption capacity and efficiency. However, this technology cannot achieve selective absorption of sulfur-containing gases.

[0006] CN105536437B discloses an MDEA composite absorbent and separation method for acid gas separation. The composite absorbent is composed of MDEA, water-immiscible chlorpyrifos, and water. Before absorbing the acid gas, it is a homogeneous phase. After absorbing the acid gas, it forms a liquid-liquid two-phase. The upper liquid phase is a lean liquid phase loaded with acid gas, and the lower liquid phase is a rich liquid phase loaded with acid gas. Only the rich liquid phase enters the desorption unit, which can reduce the desorption energy consumption. However, this technology cannot achieve selective absorption of sulfur-containing gases. Summary of the Invention

[0007] To solve the above technical problems, the purpose of the present invention is to provide an organic amine composite desulfurizer and its preparation method, and a fuel gas desulfurization method, so as to obtain an organic amine composite desulfurizer for selective deep desulfurization of refinery fuel gas.

[0008] To achieve the above object, the present invention provides an organic amine composite desulfurizer, the raw materials of which include, by mass percentage: 35-65% of s-triazine derivative, 0.1-2.0% of organic strong base, 1.0-5.0% of inorganic salt, and the balance of water;

[0009] Wherein, the structural formula of the s-triazine derivative is shown in Formula I,

[0010]

[0011] In formula I, R1, R2, and R3 are each independently selected from C1-C4 alkyl, C1-C4 hydroxyalkyl, C1-C4 alkoxy, and C1-C4 alkenyl.

[0012] Refinery fuel gas has a complex composition, including large amounts of hydrogen and low-carbon alkanes, as well as carbon dioxide, sulfides, and other inorganic gases. Carbon dioxide and hydrogen sulfide, a component of sulfides, are most similar in acidity, making them prone to co-absorption during absorption, severely impacting deep desulfurization effectiveness and sulfur capacity. The present invention's organic amine composite desulfurizer, whose primary components are s-triazine and its derivatives, can undergo selective nucleophilic substitution reactions with H2S at high pH values, while remaining unaffected by CO2. The resulting products of the nucleophilic substitution reactions are small-molecule organic amines that can continue to react with H2S, further increasing the sulfur capacity of the organic amine desulfurizer.

[0013] According to a specific embodiment of the present invention, preferably, R1, R2, and R3 are each independently selected from -CH(CH3)2, -C(CH3)3, -CH2CH2OH, -CH2CH(OH)CH3, -OCH2CH3, -OCH(CH3)2, -CH2CH=CH2 or -CH2CH2CH=CH2.

[0014] According to a specific embodiment of the present invention, preferably, R1, R2, and R3 are each independently selected from -CH(CH3)2, -C(CH3)3, -CH2CH(OH)CH3, -OCH2CH3, and -OCH(CH3)2.

[0015] The synthesis method of s-triazine derivatives is as follows: s-triazine derivatives of different structures are obtained by condensing corresponding organic amines containing substituents (R1, R2, R3) with formaldehyde in the presence of a catalyst. The ratio of organic amines of different structures can be adjusted to obtain s-triazine derivatives with different substituents.

[0016]

[0017] For example: a four-necked flask equipped with an electric stirrer and a condenser is placed in a microwave reactor, and then 405.81 g of a 37% formaldehyde aqueous solution (5 mol) is added to the four-necked flask, followed by slowly adding 305.6 g (5 mol) of ethoxyamine (CH3CH2ONH2) and 0.7 g of N,N-dimethylguanidine to the flask. The mixture is stirred and heated in a microwave for 1 hour, and the reaction temperature is controlled not to exceed 60°C. After the addition is completed, the mixture is kept warm at 60°C for 3 hours and cooled to room temperature to obtain a colorless, transparent, viscous s-triazine derivative product.

[0018] From the perspective of molecular structure, the strong electron-withdrawing effect of the N atom on the s-triazine ring makes the C atom on the ring electrophilic. After the N atom is protonated, the electrophilicity of the C atom on the ring is enhanced, which promotes the s-triazine derivative to S 2- Therefore, the substituents on the N atom on the s-triazine ring have an electron-donating effect, which promotes the protonation reaction of the N atom. The present invention uses 2-hydroxypropane and tert-butyl as substituents, which have a significant electron-donating effect, greatly promoting the nucleophilic reaction activity of the s-triazine derivatives with H2S, thereby significantly improving the desulfurization effect of the s-triazine derivatives.

[0019] According to a specific embodiment of the present invention, preferably, the pH value of the organic amine composite desulfurizer is 8-12, more preferably 9-11.

[0020] According to a specific embodiment of the present invention, preferably, the organic strong base includes a quaternary ammonium base and / or a guanidine compound.

[0021] According to a specific embodiment of the present invention, preferably, the quaternary ammonium base includes one or a combination of two or more of choline, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, and adamantyltrimethylammonium hydroxide.

[0022] According to a specific embodiment of the present invention, preferably, the guanidine compound includes one or a combination of two or more of N,N-dimethylguanidine, N-methyl-N-ethylguanidine, dimethylbiguanidine, phenformin, and butylbiguanide.

[0023] The nucleophilic substitution reaction between s-triazine organic amines and H2S requires a high pH in the solution system, generally between 8 and 12. This pH range ensures high activity in the reaction between s-triazine organic amines and hydrogen sulfide. The alkalinity generated by s-triazine derivatives decreases as the desulfurization reaction proceeds. At low pH values, s-triazine and its derivatives undergo significant hydrolysis, competing with the nucleophilic substitution reaction and severely impacting the deep desulfurization effect. Therefore, the present invention maintains a high pH in the solution system by adding a strong organic base, such as a quaternary ammonium base or a guanidine compound, to ensure the effective conduct of the nucleophilic substitution reaction.

[0024] According to a specific embodiment of the present invention, preferably, the inorganic salt includes one or a combination of two or more of NaCl, KCl, NaBr, KBr, NaF, KF, MgCl2, CaCl2, Na2SO4, K2SO4, NaNO3, and KNO3.

[0025] The product of the nucleophilic substitution reaction between s-triazine derivatives and H2S is a small molecule organic amine. This type of small molecule organic amine can undergo a non-selective acid-base neutralization reaction with H2S and CO2, thereby reducing the sulfur capacity of the organic amine composite desulfurizer. The present invention, by adding a certain amount of inorganic salt substances, can produce a significant salting-out effect on CO2, significantly reducing the solubility of CO2 in the solution and thus preventing its absorption, thereby effectively improving the sulfur absorption effect and sulfur capacity of the organic amine composite desulfurizer. At the same time, due to the salting-out effect of the inorganic salts, CO2 is basically not absorbed, the reaction of CO2 with the organic strong base is avoided, and the consumption of the organic strong base in the system by CO2 is significantly reduced, thereby effectively ensuring the high activity of the s-triazine derivative in the hydrogen sulfide reaction.

[0026] The present invention also provides a method for preparing the organic amine composite desulfurizer, which comprises the following steps: dissolving an s-triazine derivative in water, then sequentially adding an inorganic salt and an organic strong base, and adjusting the pH value of the solution to 8-12 to obtain the organic amine composite desulfurizer.

[0027] The total sulfur content in refinery fuel gas is 20.0-100.0 mg / m 3 If it can be reduced to 2.0 mg / m 3If the exhaust gas temperature is lower than 80-100°C, the exhaust gas temperature can be reduced to 80-100°C. At the same time, the auxiliary heating furnace waste heat recovery modification can increase the heating furnace efficiency to about 95%. However, in addition to sulfides (hydrogen sulfide, mercaptans, sulfides, carbonyl sulfide, and carbon disulfide), the fuel gas also contains 0.1-3.0% carbon dioxide, which is easily co-absorbed with hydrogen sulfide and other substances, seriously affecting the deep desulfurization effect.

[0028] The present invention also provides a method for desulfurizing fuel gas, which uses the above-mentioned organic amine composite desulfurizer, wherein the fuel gas contains sulfide and carbon dioxide; the desulfurization method comprises: performing gas-liquid mass transfer between the fuel gas and the organic amine composite desulfurizer to complete desulfurization; wherein the liquid-to-gas ratio of the organic amine composite desulfurizer to the fuel gas is 3-10 L / m 3 .

[0029] The organic amine composite desulfurizer of the present invention can selectively and deeply remove sulfides in the fuel gas under the condition that CO2 exists in the fuel gas, meeting the strict requirements of heating furnace efficiency improvement on the total sulfur content in the fuel gas.

[0030] In the above-mentioned fuel gas desulfurization method, preferably, the fuel gas further contains hydrogen and C1-C6 low-carbon alkanes.

[0031] In the above-mentioned desulfurization method of fuel gas, preferably, the total sulfur content of the fuel gas is 20-100 mg / m 3 .

[0032] In the above-mentioned fuel gas desulfurization method, preferably, the volume content of carbon dioxide in the fuel gas is 0.1-3.0% (V / V).

[0033] In the above-mentioned fuel gas desulfurization method, preferably, the gas-liquid mass transfer process is carried out at 15-45°C.

[0034] In the above-mentioned fuel gas desulfurization method, preferably, the gas-liquid mass transfer process is carried out in a high-gravity rotating packed bed, and the high-gravity factor is 70-110.

[0035] In the above-mentioned fuel gas desulfurization method, preferably, the high-gravity rotating packed bed is filled with a filler, and the surface area of ​​the filler is 1000-1200m 2 / m 3 ; The filler is stainless steel wire mesh and / or stainless steel corrugated plate.

[0036] According to a specific embodiment of the present invention, preferably, the method for desulfurizing fuel gas using a high-gravity rotating packed bed is as follows:

[0037] First, the fuel gas is introduced from the middle and lower part of the supergravity device through a fan, and the above-mentioned organic amine composite desulfurizer enters from the axial upper liquid inlet of the supergravity device. Under the action of centrifugal force, the organic amine composite desulfurizer absorption liquid is distributed on the packing surface along the radial direction of the rotating packing bed. The fuel gas and the organic amine absorbent are in countercurrent contact on the packing surface to carry out gas-liquid mass transfer. The sulfide in the fuel gas is selectively absorbed by the organic amine composite desulfurizer. The treated fuel gas is discharged from the gas outlet through the axial gas channel of the supergravity device.

[0038] The technical solution provided by the present invention has the following beneficial effects:

[0039] The organic amine composite desulfurizer of the present invention comprises an s-triazine derivative that can selectively undergo a nucleophilic substitution reaction with H2S under high pH conditions without reacting with CO2. The nucleophilic substitution reaction product can continue to react with H2S, thereby increasing the sulfur capacity of the organic amine composite desulfurizer. The present invention also maintains a high pH reaction environment in the solution system by adding a strong organic base such as a quaternary ammonium base or a guanidine compound, thereby ensuring the effective conduct of the nucleophilic substitution reaction. The present invention also adds an inorganic salt substance to produce a significant salting-out effect on CO2, significantly reducing its solubility in the solution and preventing its absorption. Since the sulfur capacity of a desulfurizer is positively correlated with its absorption efficiency, the above technical means can effectively improve the sulfur absorption effect and sulfur capacity of the organic amine composite desulfurizer. DETAILED DESCRIPTION

[0040] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be understood as limiting the scope of implementation of the present invention.

[0041] The general structural formula of the s-triazine derivatives used in the specific embodiments of the present invention is shown in Formula I.

[0042] Example 1

[0043] The present invention provides an organic amine composite desulfurizer, and the preparation method thereof is as follows:

[0044] 105 kg of s-triazine derivative (R1, R2, R3 are all -CH(CH3)2), 6 kg of Na2SO4, and 9 kg of tetraethylammonium hydroxide were added to 180 kg of tap water in sequence to form a homogeneous and stable organic amine composite desulfurizer. The pH value of the desulfurizer solution was 8.2.

[0045] This embodiment also provides a method for desulfurizing fuel gas, using the organic amine composite desulfurizer prepared in this embodiment, as follows:

[0046] A field test of deep desulfurization of fuel gas was carried out in a refinery. The prepared organic amine composite desulfurizer was added to the liquid storage tank of the supergravity absorption device to conduct gas-liquid mass transfer with the fuel gas. The fuel gas intake was controlled at 500Nm 3 / h, hypergravity factor is 50, liquid-gas ratio is 10L / m 3 , the absorption temperature is 15-25℃, and a selective absorption test of hydrogen sulfide is carried out.

[0047] The total sulfur content in the gas was determined according to "Determination of Sulfur Compounds in Natural Gas - Part 8: Determination of Total Sulfur Content by Ultraviolet Fluorescence Spectrophotometry" (GB / T 11060.8-2012) using a German Photon LAB TS total sulfur analyzer. The carbon dioxide content in the gas was determined according to "Stationary Source Exhaust Gas - Determination of Carbon Dioxide - Non-dispersive Infrared Absorption Method" (HJ 870-2017).

[0048] The calculation formula for fuel gas desulfurization selectivity is: Desulfurization selectivity = mass of desulfurizer consumed in desulfurization / total mass of desulfurizer consumed = mass of desulfurizer consumed in desulfurization / (mass of desulfurizer consumed in desulfurization + mass of desulfurizer consumed by self-hydrolysis). Since sulfide and desulfurizer react in equal amounts and the self-hydrolysis rate of desulfurizer is 1%, the calculation formula for desulfurization selectivity can be simplified as: Desulfurization selectivity = total sulfur absorption rate / (total sulfur absorption rate + 1).

[0049] The results of the fuel gas selective absorption test are shown in Table 1 below.

[0050] Table 1 Fuel gas selective absorption test results

[0051]

[0052]

[0053] Example 2

[0054] The present invention provides an organic amine composite desulfurizer, and the preparation method thereof is as follows:

[0055] 120 kg of s-triazine derivative (R1, R2, R3 are all -OCH2CH3), 7.5 kg of KNO3, and 4.5 kg of tetrabutylammonium hydroxide were added to 168 kg of tap water in sequence to form a homogeneous and stable organic amine composite desulfurizer. The pH value of the desulfurizer solution was 9.4.

[0056] This embodiment also provides a method for desulfurizing fuel gas, using the organic amine composite desulfurizer prepared in this embodiment, as follows:

[0057] A field test of deep desulfurization of fuel gas was carried out in a refinery. The prepared organic amine composite desulfurizer was added to the liquid storage tank of the supergravity absorption device to conduct gas-liquid mass transfer with the fuel gas. The fuel gas intake was controlled at 500Nm 3 / h, hypergravity factor is 85, liquid-gas ratio is 8L / m 3 , the absorption temperature is 30-45℃, and a selective absorption test of hydrogen sulfide is carried out.

[0058] The total sulfur content in the gas was determined according to "Determination of Sulfur Compounds in Natural Gas - Part 8: Determination of Total Sulfur Content by Ultraviolet Fluorescence Spectrophotometry" (GB / T 11060.8-2012) using a German Photon LAB TS total sulfur analyzer. The carbon dioxide content in the gas was determined according to "Stationary Source Exhaust Gas - Determination of Carbon Dioxide - Non-dispersive Infrared Absorption Method" (HJ 870-2017).

[0059] The results of the fuel gas selective absorption test are shown in Table 2.

[0060] Table 2 Fuel gas selective absorption test results

[0061]

[0062]

[0063] Example 3

[0064] The present invention provides an organic amine composite desulfurizer, and the preparation method thereof is as follows:

[0065] 195 kg of s-triazine derivatives (R1, R2, and R3 are all -CH2CH=CH2), 15 kg of KCl, and 0.3 kg of N,N-dimethylguanidine were sequentially added into 89.7 kg of tap water to form a homogeneous and stable organic amine composite desulfurizer. The pH value of the desulfurizer solution was 10.2.

[0066] This embodiment also provides a method for desulfurizing fuel gas, using the organic amine composite desulfurizer prepared in this embodiment, as follows:

[0067] A field test of deep desulfurization of fuel gas was carried out in a refinery. The prepared organic amine composite desulfurizer was added to the liquid storage tank of the supergravity absorption device to conduct gas-liquid mass transfer with the fuel gas. The fuel gas intake was controlled at 500Nm 3 / h, hypergravity factor is 130, liquid-gas ratio is 3L / m 3 , the absorption temperature is 25-35℃, and a selective absorption test of hydrogen sulfide is carried out.

[0068] The total sulfur content in the gas was determined according to "Determination of Sulfur Compounds in Natural Gas - Part 8: Determination of Total Sulfur Content by Ultraviolet Fluorescence Spectrophotometry" (GB / T 11060.8-2012) using a German Photon LAB TS total sulfur analyzer. The carbon dioxide content in the gas was determined according to "Stationary Source Exhaust Gas - Determination of Carbon Dioxide - Non-dispersive Infrared Absorption Method" (HJ 870-2017).

[0069] The results of the fuel gas selective absorption test are shown in Table 3.

[0070] Table 3 Fuel gas selective absorption test results

[0071]

[0072]

[0073] Example 4

[0074] The present invention provides an organic amine composite desulfurizer, and the preparation method thereof is as follows:

[0075] 150 kg of s-triazine derivative (R1, R2, and R3 are all -CH2CH2OH), 2 kg of KF, 1 kg of NaCl, and 1.5 kg of dimethylbiguanide were sequentially added into 145.5 kg of tap water to form a homogeneous and stable organic amine composite desulfurizer, and the pH value of the desulfurizer solution was 12.0.

[0076] This embodiment also provides a method for desulfurizing fuel gas, using the organic amine composite desulfurizer prepared in this embodiment, as follows:

[0077] A field test of deep desulfurization of fuel gas was carried out in a refinery. The prepared organic amine composite desulfurizer was added to the liquid storage tank of the supergravity absorption device to conduct gas-liquid mass transfer with the fuel gas. The fuel gas intake was controlled at 500Nm 3 / h, hypergravity factor is 95, liquid-gas ratio is 5L / m 3 , the absorption temperature is 20-25℃, and a selective absorption test of hydrogen sulfide is carried out.

[0078] The total sulfur content in the gas was determined according to "Determination of Sulfur Compounds in Natural Gas - Part 8: Determination of Total Sulfur Content by Ultraviolet Fluorescence Spectrophotometry" (GB / T 11060.8-2012) using a German Photon LAB TS total sulfur analyzer. The carbon dioxide content in the gas was determined according to "Stationary Source Exhaust Gas - Determination of Carbon Dioxide - Non-dispersive Infrared Absorption Method" (HJ 870-2017).

[0079] The results of the fuel gas selective absorption test are shown in Table 4.

[0080] Table 4 Fuel gas selective absorption test results

[0081]

[0082]

[0083] Example 5

[0084] The present invention provides an organic amine composite desulfurizer, and the preparation method thereof is as follows:

[0085] 144 kg of s-triazine derivative (two of R1, R2, and R3 are -CH2CH2OH and one is -CH(CH3)2), 2.5 kg of KCl, 8 kg of NaF, 1.6 kg of tetramethylammonium hydroxide, and 0.8 kg of butyl biguanide are successively added to 143.1 kg of tap water to form a homogeneous and stable organic amine composite desulfurizer, and the pH value of the desulfurizer solution is 9.5.

[0086] This embodiment also provides a method for desulfurizing fuel gas, using the organic amine composite desulfurizer prepared in this embodiment, as follows:

[0087] A field test of deep desulfurization of fuel gas was carried out in a refinery. The prepared organic amine composite desulfurizer was added to the liquid storage tank of the supergravity absorption device to conduct gas-liquid mass transfer with the fuel gas. The fuel gas intake was controlled at 500Nm 3 / h, hypergravity factor is 110, liquid-gas ratio is 7L / m 3 , the absorption temperature is 20-30℃, and a selective absorption test of hydrogen sulfide is carried out.

[0088] The total sulfur content in the gas was determined according to "Determination of Sulfur Compounds in Natural Gas - Part 8: Determination of Total Sulfur Content by Ultraviolet Fluorescence Spectrophotometry" (GB / T 11060.8-2012) using a German Photon LAB TS total sulfur analyzer. The carbon dioxide content in the gas was determined according to "Stationary Source Exhaust Gas - Determination of Carbon Dioxide - Non-dispersive Infrared Absorption Method" (HJ 870-2017).

[0089] The results of the fuel gas selective absorption test are shown in Table 5.

[0090] Table 5 Fuel gas selective absorption test results

[0091]

[0092]

[0093] Example 6

[0094] The present invention provides an organic amine composite desulfurizer, and the preparation method thereof is as follows:

[0095] 208 kg of s-triazine derivatives (two of R1, R2, and R3 are -CH2CH(OH)CH3, and one is -OCH2CH3), 9.1 kg of KF, 2.1 kg of Na2SO4, 9.1 kg of tetraethylammonium hydroxide, and 2.1 kg of N, N-dimethylguanidine were added sequentially into 176 kg of tap water to form a homogeneous and stable organic amine composite desulfurizer. The pH value of the desulfurizer solution was 10.5.

[0096] This embodiment also provides a method for desulfurizing fuel gas, using the organic amine composite desulfurizer prepared in this embodiment, as follows:

[0097] A field test of deep desulfurization of fuel gas was carried out in a refinery. The prepared organic amine composite desulfurizer was added to the liquid storage tank of the supergravity absorption device to conduct gas-liquid mass transfer with the fuel gas. The fuel gas intake was controlled at 1000 Nm 3 / h, hypergravity factor is 105, liquid-gas ratio is 6L / m 3 , the absorption temperature is 25-40℃, and a selective absorption test of hydrogen sulfide is carried out.

[0098] The total sulfur content in the gas was determined according to "Determination of Sulfur Compounds in Natural Gas - Part 8: Determination of Total Sulfur Content by Ultraviolet Fluorescence Spectrophotometry" (GB / T 11060.8-2012) using a German Photon LAB TS total sulfur analyzer. The carbon dioxide content in the gas was determined according to "Stationary Source Exhaust Gas - Determination of Carbon Dioxide - Non-dispersive Infrared Absorption Method" (HJ 870-2017).

[0099] The results of the fuel gas selective absorption test are shown in Table 6.

[0100] Table 6 Fuel gas selective absorption test results

[0101]

[0102]

[0103] Example 7

[0104] The present invention provides an organic amine composite desulfurizer, and the preparation method thereof is as follows:

[0105] 200 kg of s-triazine derivatives (one of R1, R2, and R3 is -CH2CH(OH)CH3, and two are -C(CH3)3), 13.1 kg of KF, 4.2 kg of KNO3, 4.3 kg of tetrabutylammonium hydroxide, and 1.8 kg of dimethylbiguanide were added sequentially to 176.8 kg of tap water to form a homogeneous and stable organic amine composite desulfurizer. The pH value of the desulfurizer solution was 10.6.

[0106] This embodiment also provides a method for desulfurizing fuel gas, using the organic amine composite desulfurizer prepared in this embodiment, as follows:

[0107] A field test of deep desulfurization of fuel gas was carried out in a refinery. The prepared organic amine composite desulfurizer was added to the liquid storage tank of the supergravity absorption device to conduct gas-liquid mass transfer with the fuel gas. The fuel gas intake was controlled at 1000 Nm 3 / h, hypergravity factor is 100, liquid-gas ratio is 5L / m 3 , the absorption temperature is 20-35℃, and a selective absorption test of hydrogen sulfide is carried out.

[0108] The total sulfur content in the gas was determined according to "Determination of Sulfur Compounds in Natural Gas - Part 8: Determination of Total Sulfur Content by Ultraviolet Fluorescence Spectrophotometry" (GB / T 11060.8-2012) using a German Photon LAB TS total sulfur analyzer. The carbon dioxide content in the gas was determined according to "Stationary Source Exhaust Gas - Determination of Carbon Dioxide - Non-dispersive Infrared Absorption Method" (HJ 870-2017).

[0109] The results of the fuel gas selective absorption test are shown in Table 7.

[0110] Table 7 Fuel gas selective absorption test results

[0111]

[0112]

[0113] Through the above examples, it can be found that the composite desulfurizer system formed by different combinations of substituents in s-triazine derivatives, especially substituents with strong electron-donating effects, different combinations of quaternary ammonium bases and organic guanidine strong bases, and different combinations of inorganic salts can achieve deep desulfurization of fuel gas while having good desulfurization selectivity, thereby effectively improving the desulfurization efficiency, selectivity and sulfur capacity of the desulfurizer.

[0114] Comparative Example 1: Influence of Substituents on Triazine Derivatives

[0115] Preparation of composite desulfurizer A1: 7.0 kg of s-triazine derivative (all substituted with 2-methylethane), 0.3 kg of NaF, 0.1 kg of KNO3, and 0.20 kg of tetraethylammonium hydroxide were added to 12.4 kg of tap water in sequence to form a homogeneous and stable organic amine composite desulfurizer A1. The pH value of the desulfurizer solution was 10.0.

[0116] Preparation of comparative desulfurizer B1: 7.0 kg of s-triazine, 0.3 kg of NaF, 0.1 kg of KNO3, and 0.20 kg of tetraethylammonium hydroxide were added sequentially into 12.4 kg of tap water to form a homogeneous and stable organic amine composite desulfurizer B1. The pH value of the desulfurizer solution was 10.0.

[0117] The prepared organic amine composite desulfurizer A1 and the comparative desulfurizer B1 were added to the liquid storage tanks of two high-gravity absorption devices in equal amounts to conduct gas-liquid mass transfer with the fuel gas. The simulated fuel gas was a mixed gas containing hydrogen sulfide and carbon dioxide. The air intake of the high-gravity absorption test device was controlled to be 20m 3 / h, hypergravity factor is 90, liquid-gas ratio is 5L / m 3 , the absorption temperature is 20-30℃, and a selective absorption test of hydrogen sulfide is carried out.

[0118] The total sulfur content in the gas was determined according to "Determination of Sulfur Compounds in Natural Gas - Part 8: Determination of Total Sulfur Content by Ultraviolet Fluorescence Spectrophotometry" (GB / T 11060.8-2012) using a German Photon LAB TS total sulfur analyzer. The results of the fuel gas absorption test are shown in Table 8.

[0119] Table 8 Fuel gas absorption test results

[0120]

[0121]

[0122] It can be seen from this that, compared with s-triazine, the s-triazine derivatives used in the present invention can better improve the desulfurization effect of the desulfurizer.

[0123] Comparative Example 2: Influence of Optimization of the Substituent Structure of Triazine Derivatives

[0124] Preparation of composite desulfurizer A2: 8.0 kg of s-triazine derivative (with two 2-hydroxypropane substituents and one tert-butyl group), 0.5 kg of KF, 0.2 kg of NaCl, and 0.3 kg of dimethylbiguanide were added to 11.0 kg of tap water in sequence to form a homogeneous and stable organic amine composite desulfurizer A2. The pH value of the desulfurizer solution was 10.5.

[0125] Preparation of comparative desulfurizer B2: 8.0 kg of s-triazine derivatives (all substituents are triethylenetetramine, derived from comparative patent CN107418641A), 0.5 kg of KF, 0.2 kg of NaCl, and 0.3 kg of dimethylbiguanide were sequentially added to 11.0 kg of tap water to form a homogeneous and stable organic amine composite desulfurizer B2. The pH value of the desulfurizer solution was 10.5.

[0126] The prepared organic amine composite desulfurizer A2 and the comparative desulfurizer B2 were added in equal amounts into the liquid storage tanks of two high-gravity absorption devices to conduct gas-liquid mass transfer with the fuel gas. The simulated fuel gas was a mixed gas containing hydrogen sulfide and carbon dioxide. The air intake of the high-gravity absorption test device was controlled to be 20m 3 / h, hypergravity factor is 80, liquid-gas ratio is 7L / m 3 , the absorption temperature is 25-35℃, and a selective absorption test of hydrogen sulfide is carried out.

[0127] The total sulfur content in the gas was determined according to the “Determination of sulfur compounds in natural gas - Part 8: Determination of total sulfur content by ultraviolet fluorescence spectrophotometry” (GB / T 11060.8-2012) using a German Photon LAB TS total sulfur analyzer.

[0128] The results of the fuel gas absorption test are shown in Table 9.

[0129] Table 9 Fuel gas absorption test results

[0130]

[0131]

[0132] This indicates that, because the s-triazine derivative in comparative desulfurizer B2 is substituted with triethylenetetramine, this substituent exhibits an electron-withdrawing effect, which weakens the nucleophilic reactivity of the s-triazine derivative toward hydrogen sulfide, resulting in reduced desulfurization efficiency. A stronger electron-donating effect on the s-triazine derivative substituent would enhance the nucleophilic reactivity of the s-triazine derivative toward hydrogen sulfide, further improving desulfurization efficiency. Therefore, the composite desulfurizer A2 prepared using the method of the present invention exhibits a more pronounced desulfurization effect.

[0133] Comparative Example 3: Influence of Organic Strong Base

[0134] Preparation of composite desulfurizer A3: 10.0 kg of s-triazine derivative (the substituents are one 2-hydroxypropane and two ethoxy groups), 0.5 kg of NaF, 0.12 kg of tetraethylammonium hydroxide, and 0.12 kg of N,N-dimethylguanidine were added sequentially to 9.26 kg of tap water to form a homogeneous and stable organic amine composite desulfurizer A3. The pH value of the desulfurizer solution was 11.0.

[0135] Preparation of comparative desulfurizer B3: 10.0 kg of s-triazine derivative (with one 2-hydroxypropane and two ethoxy groups as substituents) and 0.5 kg of NaF were sequentially added to 9.50 kg of tap water to form a homogeneous and stable organic amine composite desulfurizer B3. The pH value of the desulfurizer solution was 7.5.

[0136] The prepared organic amine composite desulfurizer A3 and comparative desulfurizer B3 were added to the liquid storage tanks of two high-gravity absorption devices in equal amounts to conduct gas-liquid mass transfer with the fuel gas. The simulated fuel gas was a mixed gas containing hydrogen sulfide and carbon dioxide. The air intake of the high-gravity absorption test device was controlled to be 20m 3 / h, hypergravity factor is 110, liquid-gas ratio is 10L / m 3 , the absorption temperature is 20-35℃, and a selective absorption test of hydrogen sulfide is carried out.

[0137] The total sulfur content in the gas was determined according to the “Determination of sulfur compounds in natural gas - Part 8: Determination of total sulfur content by ultraviolet fluorescence spectrophotometry” (GB / T 11060.8-2012) using a German Photon LAB TS total sulfur analyzer.

[0138] The results of the fuel gas absorption test are shown in Table 10.

[0139] Table 10 Fuel gas absorption test results

[0140]

[0141]

[0142] It can be seen from this that when the desulfurizer maintains appropriate alkalinity and its pH value is kept within an appropriate range, it is more conducive to improving the desulfurization efficiency.

[0143] Comparative Example 4 investigates the influence of inorganic salts

[0144] Preparation of composite desulfurizer A4: 9.0 kg of s-triazine derivative (all substituents are ethoxy), 0.64 kg of KF, and 0.16 kg of tetramethylammonium hydroxide were added to 10.2 kg of tap water in sequence to form a homogeneous and stable organic amine composite desulfurizer A4. The pH value of the desulfurizer solution was 9.5.

[0145] Preparation of comparative desulfurizer B4: 9.0 kg of s-triazine derivatives (all substituents are ethoxy) and 0.16 kg of tetramethylammonium hydroxide were sequentially added into 10.84 kg of tap water to form a homogeneous and stable organic amine composite desulfurizer B4. The pH value of the desulfurizer solution was 9.5.

[0146] The prepared organic amine composite desulfurizer A4 and the comparative desulfurizer B4 were added to the liquid storage tanks of two high-gravity absorption devices in equal amounts to conduct gas-liquid mass transfer with the fuel gas. The simulated fuel gas was a mixed gas containing hydrogen sulfide and carbon dioxide. The air intake of the high-gravity absorption test device was controlled to be 20m 3 / h, hypergravity factor is 130, liquid-gas ratio is 4L / m 3 , the absorption temperature is 15-30℃, and a selective absorption test of hydrogen sulfide is carried out.

[0147] The total sulfur content in the gas was determined according to the “Determination of sulfur compounds in natural gas - Part 8: Determination of total sulfur content by ultraviolet fluorescence spectrophotometry” (GB / T 11060.8-2012) using a German Photon LAB TS total sulfur analyzer.

[0148] The results of the fuel gas absorption test are shown in Table 11.

[0149] Table 11 Fuel gas absorption test results

[0150]

[0151]

[0152] It can be seen from this that the present invention adds inorganic salts and utilizes the salting-out effect to significantly reduce the solubility of CO2 in the solution to prevent it from being absorbed, thereby improving the sulfur absorption effect of the organic amine composite desulfurizer.

Claims

1. An organic amine composite desulfurizer, whose raw materials include, by mass percentage: 35-65% of s-triazine derivative, 0.1-2.0% of organic strong base, 1.0-5.0% of inorganic salt, and the balance is water; Wherein, the structural formula of the s-triazine derivative is as shown in Formula I, In formula I, R1, R2, and R3 are each independently selected from C1-C4 alkyl, C1-C4 hydroxyalkyl, C1-C4 alkoxy, and C1-C4 alkenyl.

2. The organic amine composite desulfurizing agent according to claim 1, wherein: R1, R2, R3 are each independently selected from -CH(CH3)2, -C(CH3)3, -CH2CH2OH, -CH2CH(OH)CH3, -OCH2CH3, -OCH(CH3)2, -CH2CH=CH2 or -CH2CH2CH=CH2.

3. The organic amine composite desulfurizing agent according to claim 1, wherein: R1, R2, and R3 are each independently selected from -CH(CH3)2, -C(CH3)3, -CH2CH(OH)CH3, -OCH2CH3, and -OCH(CH3)2.

4. The organic amine composite desulfurizing agent according to claim 1, wherein: The pH value of the organic amine composite desulfurizer is 8-12, preferably 9-11.

5. The organic amine composite desulfurizing agent according to claim 1, wherein: The organic strong base includes a quaternary ammonium base and / or a guanidine compound.

6. The organic amine composite desulfurizing agent according to claim 5, wherein: The quaternary ammonium base includes one or a combination of two or more of choline, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide and adamantyltrimethylammonium hydroxide.

7. The organic amine composite desulfurizing agent according to claim 5, wherein: The guanidine compound includes one or a combination of two or more of N,N-dimethylguanidine, N-methyl-N-ethylguanidine, dimethylbiguanidine, phenformin, and butylbiguanide.

8. The organic amine composite desulfurizing agent according to claim 1, wherein: The inorganic salt includes one or a combination of two or more of NaCl, KCl, NaBr, KBr, NaF, KF, MgCl2, CaCl2, Na2SO4, K2SO4, NaNO3, and KNO3.

9. A method for preparing the organic amine composite desulfurizer according to any one of claims 1 to 8, comprising the following steps: dissolving an s-triazine derivative in water, then sequentially adding an inorganic salt and an organic strong base, and adjusting the pH value of the solution to 8-12 to obtain the organic amine composite desulfurizer.

10. A method for desulfurizing fuel gas, which uses the organic amine composite desulfurizer according to any one of claims 1 to 8, wherein the fuel gas contains sulfide and carbon dioxide; The desulfurization method comprises: The fuel gas and the organic amine composite desulfurizer are subjected to gas-liquid mass transfer to complete desulfurization; wherein the liquid-gas ratio of the organic amine composite desulfurizer to the fuel gas is 3-10 L / m 3 .

11. The method for desulfurizing fuel gas according to claim 10, wherein: The total sulfur content of the fuel gas is 20-100 mg / m 3 ; Preferably, the volume content of carbon dioxide in the fuel gas is 0.1-3.0%; Preferably, the gas-liquid mass transfer process is carried out at 15-45°C.

12. The method for desulfurizing fuel gas according to claim 10, wherein: The gas-liquid mass transfer process is carried out in a high-gravity rotating packed bed with a high-gravity factor of 70-110; Preferably, the high gravity rotating packed bed is filled with a filler having a surface area of ​​1000-1200m 2 / m 3 ; Preferably, the filler is a stainless steel wire mesh and / or a stainless steel corrugated plate.

Images