Selective absorbent of hydrogen sulfide, preparation method of selective absorbent and treatment method of sulfide in fuel gas

Abstract

The invention discloses a hydrogen sulfide selective absorbent which comprises the following components in percentage by mass: 40%-60% of homogeneous nitrogen compounds, 0.5%-2.0% of an activating agent, 1.5%-4.0% of a degradation inhibitor and the balance of water, the selective absorbent has high hydrogen sulfide selectivity and does not absorb carbon dioxide. The invention also provides a method for treating the sulfides in the fuel gas, the low-concentration fuel gas mainly containing carbonyl sulfide and carbon disulfide sulfides in an oil refinery is subjected to deep desulfurization treatment by adopting normal-temperature and low-temperature organic sulfur hydrolysis combined with supergravity absorption and the selective absorbent, the total sulfur content is reduced to 2 mg / m < 3 > or below, and the sulfur content is reduced to 2 mg / m < 3 > or below. Therefore, the exhaust gas temperature of the heating furnace is reduced, the heat efficiency of the heating furnace is improved, the absorption liquid circulation volume and the energy consumption of the heating furnace are reduced, and both the investment cost and the operation cost are low.

Description

Technical Field

[0001] The present invention relates to the field of energy conservation and environmental protection in refining and chemical enterprises, and in particular to a selective absorbent for hydrogen sulfide and a preparation method thereof, and a method for treating sulfides in fuel gas. Background Art

[0002] Crude oil processing processes such as atmospheric and vacuum distillation, catalytic cracking, catalytic reforming, hydrocracking, and delayed coking produce large amounts of gaseous hydrocarbons, known as refinery gas. Refinery gas primarily consists of H2, C1-C4 alkanes, and C2-C4 olefins, along with small amounts of C5 hydrocarbons, sulfide gases, carbon monoxide, and carbon dioxide. After gas separation and alcoholamine desulfurization, most refinery gas is used as fuel for heating furnaces.

[0003] The sulfur content of fuel gas is generally between 20 and 100 mg / m 3 , with hydrogen sulfide, methyl mercaptan, ethyl mercaptan, carbonyl sulfide and carbon disulfide as the main sulfur-containing substances. When the fuel gas is burned in the heating furnace, the sulfide is oxidized to form SO2, and part of the SO2 will be further oxidized to form SO3. SO3 will generate sulfuric acid vapor when it meets water vapor. When the flue gas temperature drops to the sulfuric acid dew point, the sulfuric acid vapor will condense on the metal surface of the furnace body and the air preheater of the heating furnace, forming sulfuric acid dew point corrosion. The acid dew point of the flue gas is related to the excess air coefficient of combustion, the water vapor content and the sulfur content in the fuel gas, among which the sulfur content in the fuel gas is the most critical influencing factor. Therefore, reducing the sulfide content in the fuel gas, reducing the sulfuric acid vapor content in the flue gas, and then reducing the acid dew point temperature of the flue gas is one of the effective means to reduce the exhaust temperature and improve the efficiency of the heating furnace.

[0004] To improve the thermal efficiency of heating furnaces, large furnaces are equipped with air preheaters. These preheat the air by exchanging heat with the flue gas, simultaneously lowering the flue gas temperature and recovering the flue gas heat. Lower flue gas temperatures increase heat recovery, improving furnace efficiency. However, excessively low flue gas temperatures can lead to acid dew point corrosion. Therefore, the exhaust gas temperature must be designed to be at least 15°C above the flue gas dew point. Currently, the exhaust gas temperature of refinery furnaces is generally controlled between 120°C and 160°C, resulting in a thermal efficiency of 91% to 93%.

[0005] Sulfides in refinery fuel gas include inorganic sulfur and organic sulfur. Inorganic sulfur is primarily treated using the conventional MDEA (N-methyldiethanolamine) absorption method. However, since fuel gas contains 0.1% to 3.0% carbon dioxide, this leads to problems such as high carbon dioxide co-absorption rates, high MDEA consumption, and high regeneration energy consumption. Organic sulfide gases, primarily containing carbonyl sulfide and carbon disulfide, are difficult to remove using conventional alkaline solution absorption methods because both have linear structures and stable properties in their gaseous state. Generally, the organic sulfur must first be converted into inorganic sulfur before treatment with solid adsorbents or alkaline solutions. However, this also results in high adsorbent or alkaline solution consumption and high carbon dioxide co-absorption rates. Alternatively, strong oxidants can be used for oxidation and absorption treatment, which also presents numerous problems.

[0006] For example, Chinese patent document CN104548926A discloses a process for removing organic sulfur. This process first involves treating a carbonyl sulfide-containing gas in a hydrogen atmosphere using an organic sulfur hydrogenation catalyst to convert the carbonyl sulfide into hydrogen sulfide. The hydrogen sulfide is then removed using a desulfurizer, thereby achieving efficient removal of sulfides. However, this organic sulfur hydrogenation catalyst cannot hydrolyze carbonyl sulfide and carbon disulfide in the fuel gas into hydrogen sulfide and carbon dioxide at room temperature. This means that the carbonyl sulfide conversion process requires high temperature and pressure, harsh and complex operating conditions, and high energy consumption. Furthermore, the hydrogen sulfide product is removed using a desulfurizer in a conventional desulfurization tower, resulting in high equipment investment and operating costs and requiring a large amount of desulfurizer.

[0007] Chinese patent document CN110982566A discloses a process for removing organic sulfur from natural gas. The organic sulfur, such as carbonyl sulfide, mercaptans, or sulfides, is catalytically hydrolyzed or thermally cracked using a catalytic adsorption-type organic sulfur desulfurizer to convert it into hydrogen sulfide. The hydrogen sulfide then reacts with the active components of the catalytic adsorption-type organic sulfur desulfurizer to form metal sulfides, which are then removed. This process is simple, highly efficient, and produces no waste liquid or gas emissions. However, the catalyst cannot hydrolyze carbonyl sulfide and carbon disulfide in the fuel gas into hydrogen sulfide and carbon dioxide at room temperature. This means that carbonyl sulfide hydrolysis requires high temperatures, and the desulfurization tower is a conventional packed tower, occupying a large area. The formation of metal sulfides can also cause secondary pollution.

[0008] Chinese patent document CN111826215A discloses a dry purification device and process for removing total sulfur from blast furnace gas. The device comprises a catalytic hydrolysis tower, a desulfurization tower, a pneumatic conveying device, and a gas replacement system. After dust removal and waste heat and pressure power generation, the blast furnace gas passes through the catalytic hydrolysis tower and the desulfurization tower in sequence. Organic sulfur species such as carbonyl sulfide and carbon disulfide are catalytically hydrolyzed and converted into hydrogen sulfide in the catalytic hydrolysis tower. A desulfurizer is supplied to the desulfurization tower via the pneumatic conveying device, absorbing hydrogen sulfide, sulfur dioxide, hydrogen chloride, and other acidic gases, thereby removing sulfur-containing substances from the blast furnace gas. Carbonyl sulfide and carbon disulfide cannot be converted into hydrogen sulfide in the catalytic hydrolysis tower at room temperature. Since blast furnace gas contains approximately 10% carbon dioxide, subsequent acid gas treatment also presents problems such as high carbon dioxide co-absorption, high desulfurizer consumption, and secondary pollution.

[0009] Chinese patent document CN108641764A discloses a device and method for removing organic sulfur from gaseous materials. The sulfur-containing gaseous materials pass through a gas distributor and enter a desulfurization extraction tower. The desulfurizer is pressurized by a desulfurizer circulation pump and enters the desulfurization extraction tower from a liquid distributor. The gas and liquid phases flow in opposite directions and contact through the extraction tower fillers in the desulfurization extraction tower. The carbonyl sulfide in the sulfur-containing gaseous materials is hydrolyzed in the desulfurization extraction tower to generate hydrogen sulfide and carbon dioxide. The generated hydrogen sulfide and the original hydrogen sulfide in the sulfur-containing gaseous materials are absorbed in the desulfurizer. The hydrogen sulfide-rich desulfurizer is partially self-circulated and partially sent to a regeneration unit. The desulfurized gaseous materials are sent out from a gas material discharge pipe at the top of the desulfurization extraction tower. The gaseous materials and the desulfurizer flow in opposite directions and contact each other in the desulfurization extraction tower. The carbonyl sulfide in the gaseous materials can be removed to 10 mg / Nm 3 Below, the total sulfur can be removed to 20mg / Nm 3 Although the organic sulfur hydrolysis catalyst in this method is a low-temperature catalyst and the desulfurizer can be regenerated and recycled, the use of a conventional tower for organic sulfur conversion, absorption, and desulfurizer regeneration, with conversion and absorption occurring within the same extraction tower, presents drawbacks such as large floor space, high investment costs, and the potential for loss of the organic sulfur hydrolysis catalyst. Furthermore, since the desulfurizer is a primary, tertiary, or secondary amine compound, there are also issues such as a high carbon dioxide co-absorption rate and high absorption liquid consumption.

[0010] Chinese patent document CN102641654B discloses a method and apparatus for treating malodorous gas. The malodorous gas mainly comprises a mixture of one or more of hydrogen sulfide, carbon disulfide, methyl mercaptan, dimethyl sulfide, acrolein, and ammonia. A gas collection device introduces the malodorous gas through an air inlet at the bottom of a deodorizing tower. Simultaneously, an oxidant is introduced through an oxidant inlet at the top of the deodorizing tower by an oxidant supply device. The oxidant is prepared by mixing 2% by mass hydrogen peroxide and ferrous sulfate in a molar ratio of 10:1, and then adjusting the pH to 2 with sulfuric acid. The malodorous gas and oxidant react in the main body of the deodorizing tower. The reacted gas is discharged through a gas outlet. The reacted oxidant collects at the bottom of the deodorizing tower and is introduced into a residual liquid treatment device through the oxidant outlet. This method has high deodorization efficiency, and the treated gas can meet the national secondary emission standard. The method is mainly used for treating high-concentration carbon disulfide. Since this method can only be implemented under acidic conditions, the equipment must be corrosion-resistant; since the deodorization tower uses a conventional tower, the equipment occupies a large area and has a high investment cost; in addition, iron salts will produce flocs after the reaction, causing secondary pollution, which may cause pipe blockage and require regular cleaning.

[0011] Chinese patent document CN112574788B discloses a method for purifying blast furnace gas, which adjusts CO2, H2S, and COS to the required product specifications. The initial blast furnace gas temperature is 80-200°C, and COS is first quenched and hydrolyzed into CO2 and H2S during the quenching process, so that the residual COS is less than 5 mg / Nm 3 Then, the H2S in the mixed gas after cooling is removed by a highly selective non-regenerative desulfurization solvent, or H2S is selectively removed and converted into elemental sulfur, so that the total sulfur in the exhaust gas is less than 10mg / Nm 3 ; Finally, the amine absorption method is used to adjust the CO2 in the blast furnace gas from the ordinary level to the chemical synthesis application level with a volume fraction as low as 0.001%; ​​when COS is hydrolyzed, a catalyst area that can be equipped with a COS hydrolysis catalyst is set at a height of 600 to 1000 mm at the top of the air inlet of the quenching equipment, and the gas can only pass through the catalyst area. The non-regenerative liquid desulfurizer is a liquid containing alkaline substances such as sodium hydroxide or sodium carbonate, or a triazine desulfurizer; the regenerative desulfurization method is an absorption process consisting of an amine solvent and a supergravity rotating bed or a micro-cyclone absorber or a dynamic wave scrubber. The regenerated H2S-rich gas enters the sulfur recovery reaction system, and the H2S content in the exhaust gas after sulfur recovery is less than 10 mg / Nm 3 Although this method can treat H2S and COS, the total sulfur content after treatment is only less than 10 mg / Nm 3 In addition, it is necessary to treat CO2 with a content of 15% to 35%, which requires the consumption of a large amount of alcohol amine, and the alcohol amine needs to be regenerated in time. Summary of the Invention

[0012] In response to the urgent need to improve the thermal efficiency of heating furnaces in oil refineries and the shortcomings of existing technologies for treating carbonyl sulfide and carbon disulfide sulfides, the present invention provides a selective absorbent for hydrogen sulfide and a preparation method. The absorbent can absorb hydrogen sulfide with high selectivity and does not absorb carbon dioxide, requires a small amount of water, and does not cause secondary pollution.

[0013] To achieve the above object, the present invention provides the following technical solutions:

[0014] A selective absorbent for hydrogen sulfide, comprising the following components, calculated by mass percentage: 40% to 60% of a nitrogen compound, 0.5% to 2.0% of an activator, 1.5% to 4.0% of a degradation inhibitor, and the balance being water;

[0015] The isocyanate compound has the following structure:

[0016]

[0017] Wherein, R' is selected from acyloxy-OCOR, and R is selected from C1-C3 linear or branched alkyl.

[0018] Optionally, in the selective absorbent for hydrogen sulfide provided by the present invention, R' is selected from any one of -OCOCH3, -OCOCH2CH3, -OCOCH2CH2CH3, and -OCOCH(CH3)2.

[0019] Optionally, in the selective absorbent for hydrogen sulfide provided by the present invention, the activator is selected from ethylenediaminetetraacetic acid or sodium ethylenediaminetetraacetate;

[0020] The degradation inhibitor is an acetic acid-sodium acetate buffer solution with a pH of 5.0 to 5.5.

[0021] Preferably, the pH value of the selective absorbent for hydrogen sulfide provided by the present invention is 9.0 to 11.0.

[0022] The present invention also provides a method for preparing the above-mentioned selective absorbent for hydrogen sulfide, comprising the following steps:

[0023] The iso-nitrogen compound is dissolved in water, and then an activator and a degradation inhibitor are added in sequence to obtain the selective absorbent for hydrogen sulfide; preferably, the pH value of the selective absorbent for hydrogen sulfide is 9.0-11.0.

[0024] The present invention also provides a method for treating sulfides in fuel gas. This method hydrolyzes carbonyl sulfide and carbon disulfide-type sulfides in refinery fuel gas into CO2 and H2S at room temperature, reducing energy consumption. The method then selectively absorbs hydrogen sulfide while excluding carbon dioxide using the aforementioned absorbent, thereby reducing absorbent usage and preventing secondary pollution. The method comprises the following steps:

[0025] 1) hydrolyzing carbonyl sulfide and carbon disulfide in the fuel gas into hydrogen sulfide and carbon dioxide at a temperature of less than 50° C. in the presence of an organic sulfur hydrolysis catalyst to obtain a mixed gas; preferably, the conversion rate of carbonyl sulfide and carbon disulfide is ≥96%;

[0026] 2) selectively absorbing hydrogen sulfide in the mixed gas without absorbing carbon dioxide using a desulfurizing agent under the action of supergravity to obtain treated fuel gas;

[0027] Wherein, the desulfurizing agent is selected from the above-mentioned selective absorbent of hydrogen sulfide.

[0028] Optionally, in the method for treating sulfides in the above-mentioned fuel gas provided by the present invention, the organic sulfur hydrolysis catalyst includes a carrier and an active component, the carrier includes activated alumina with a porosity greater than 0.7, and the active component includes an alkali metal (at least one of lithium, sodium, potassium, rubidium, cesium, etc.) and a transition metal (at least one of chromium, manganese, iron, cobalt, nickel, copper, zinc, palladium, silver, platinum, gold, etc.).

[0029] Optionally, in the above-mentioned method for treating sulfides in fuel gas provided by the present invention, any organic sulfur hydrolysis catalyst that can hydrolyze carbonyl sulfide and carbon disulfide into hydrogen sulfide and carbon dioxide at a temperature of <50°C can meet the implementation of the scheme of the present invention. The organic sulfur hydrolysis catalyst recommended by the present invention is spherical particles with a diameter of 3 to 5 mm, a crushing strength of ≥50N / particle, and a bulk density of 0.7 to 0.8 kg / L.

[0030] Optionally, in the above-mentioned method for treating sulfides in fuel gas provided by the present invention, the sulfides in the fuel gas are mainly carbonyl sulfide and carbon disulfide sulfides, and a small amount of hydrogen sulfide, and the total sulfide concentration is 20-100 mg / m 3 ;

[0031] The temperature of the fuel gas is less than 50°C, the pressure is 0.5-0.8 MPa, and the flow rate is 50-100 m 3 / h.

[0032] Optionally, in the above-mentioned method for treating sulfides in fuel gas provided by the present invention, step 1) is carried out in an organic sulfur hydrolysis tower. The organic sulfur hydrolysis tower recommended by the present invention is provided with a fuel gas inlet on the lower side wall, an exhaust port on the top, and a fixed perforated support plate and an annular gas distribution pipe composed of a series of concentric circles in sequence from top to bottom inside; an annular sealing ring is provided between the fixed perforated support plate and the inner wall of the organic sulfur hydrolysis tower; an organic sulfur hydrolysis catalyst is provided on the upper part of the fixed perforated support plate, and the particle size of the organic sulfur hydrolysis catalyst is larger than the aperture of the holes on the support plate to prevent the loss of the organic sulfur hydrolysis catalyst. An annular sealing ring is provided to prevent the organic sulfur hydrolysis catalyst from losing from the inner side wall of the organic sulfur hydrolysis tower; an annular gas distribution pipe composed of a series of concentric circles is provided to ensure sufficient and uniform contact between the fuel gas and the organic sulfur hydrolysis catalyst. Preferably, the fuel gas inlet and the exhaust port are both provided with flow control devices (such as flow regulating valves, etc.); the bottom of the organic sulfur hydrolysis tower is provided with a drainage valve to discharge wastewater when cleaning the organic sulfur hydrolysis tower.

[0033] Optionally, in the method for treating sulfides in fuel gas provided by the present invention, there are at least two organic sulfur hydrolysis towers connected in parallel, so that during operation, one is in use and the other is in standby (i.e., one organic sulfur hydrolysis tower performs organic sulfur hydrolysis, while the other is in standby). This is intended to allow automatic program-controlled valves to automatically switch to the standby tower when one organic sulfur hydrolysis tower malfunctions or requires replacement due to insufficient hydrolysis performance. This avoids production downtime during maintenance and replacement of the organic sulfur hydrolysis tower, thereby ensuring continuous and efficient operation of the organic sulfur hydrolysis towers.

[0034] Optionally, in the method for treating sulfides in fuel gas provided by the present invention, step 2) is performed in a supergravity absorption device (such as a supergravity machine) with a packing layer, and the organic sulfur hydrolysis tower is connected to the supergravity absorption device;

[0035] The packing of the packing layer is a structured stainless steel wire mesh packing or a stainless steel corrugated plate packing; preferably, the packing is a structured stainless steel wire mesh packing with a specific surface area of ​​800 to 1500 m 2 / m 3 , more preferably 1000 to 1200 m 2 / m 3 .

[0036] Optionally, in the above-mentioned method for treating sulfides in fuel gas provided by the present invention, in step 2), the mixed gas and the desulfurizer are in reverse contact with the packing layer in the supergravity absorption device; preferably, the conditions of the reverse contact are as follows: the supergravity factor is 30 to 150, the operating pressure is 0.5 to 0.8 MPa, and the liquid-gas ratio is 2.0 to 20.0 L / m 3 .

[0037] Optionally, in the above-mentioned method for treating sulfides in fuel gas provided by the present invention, the supergravity absorption device recommended by the present invention includes a drum cavity and an exchange cavity that are sequentially arranged and connected from top to bottom, the top of the drum cavity is provided with a liquid inlet, the top side wall is provided with a gas outlet, and the interior is provided with a liquid distributor; the bottom (non-center position) of the exchange cavity is provided with a liquid outlet, the side wall is provided with a gas inlet, the packing layer is located in the exchange cavity, and the exhaust port of the organic sulfur hydrolysis tower is connected to the gas inlet on the exchange cavity of the supergravity absorption device. Specifically, after the selective absorbent enters the drum cavity through the liquid inlet, it is evenly sprayed on the packing layer located in the exchange cavity through the liquid distributor, the mixed gas enters the exchange cavity from the gas inlet, and contacts with the selective absorbent in reverse to absorb hydrogen sulfide, and is then discharged from the liquid outlet located at the bottom of the exchange cavity, and the treated mixed gas is discharged from the gas outlet to the heating furnace device.

[0038] Specifically, in the above-mentioned method for treating sulfides in fuel gas provided by the present invention, the fuel gas enters from the fuel gas inlet on the lower side of the organic sulfur hydrolysis tower, and then flows from bottom to top in the organic sulfur hydrolysis tower, and uses the organic sulfur hydrolysis catalyst fixed on the perforated support plate above the annular gas distribution pipe to hydrolyze carbonyl sulfide and carbon disulfide in the fuel gas to generate hydrogen sulfide and carbon dioxide at a temperature below 50°C, especially at room temperature; the obtained mixed gas is discharged from the exhaust port of the organic sulfur hydrolysis tower, and flows through the gas inlet into the exchange chamber of the supergravity absorption device equipped with an absorbent, and passes through the packing layer in the exchange chamber under pressure to enter the exchange chamber, and the entire gas passes through the gas outlet. In the process, the mixed gas contacts and transfers mass in reverse with the absorbent which enters the inner cavity of the drum from the liquid inlet and is evenly sprayed on the packing layer in the exchange chamber by the liquid distributor. The absorbent selectively absorbs the hydrogen sulfide therein (i.e., the hydrogen sulfide molecules are dissolved and absorbed by the absorbent, and the absorbent is recycled) without absorbing carbon dioxide. The treated mixed gas is discharged from the gas outlet located in the center of the entire supergravity absorption device. The absorbent after selectively absorbing hydrogen sulfide flows radially outward under the action of the centrifugal force generated by the high-speed rotation, hits the inner wall of the stationary exchange chamber, and falls down, and is discharged from the liquid outlet located at a non-central position at the bottom of the exchange chamber to the absorbent storage tank.

[0039] In the method for treating sulfides in the above-mentioned fuel gas provided by the present invention, carbonyl sulfide and carbon disulfide sulfides are further hydrolyzed into CO2 and H2S at a temperature lower than 50°C (i.e., normal and low temperatures) in the above-mentioned organic sulfur hydrolysis tower, and then the above-mentioned absorbent is used to selectively absorb hydrogen sulfide in the above-mentioned supergravity absorption device. The various steps in the entire treatment method cooperate with each other. On the one hand, it can solve the shortcomings of the existing treatment methods such as large equipment footprint, high investment cost, and easy loss of organic sulfur hydrolysis catalyst; on the other hand, it can deeply remove carbonyl sulfide and carbon disulfide sulfides in the fuel gas used for the refinery heating furnace. When the total sulfur content of the inlet gas is 20-100 mg / m 3 The total sulfur content of the outlet gas is 2㎎ / m 3 The following reduces the dew point of sulfuric acid vapor in the flue gas of the heating furnace, reduces the exhaust temperature of the heating furnace, and improves the thermal efficiency of the heating furnace.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] 1. The selective absorbent for hydrogen sulfide provided by the present invention comprises a nitrogen compound which is a cyclic amine having the basic characteristics of an amine. The strong electron-withdrawing effect of the nitrogen atom on the ring makes the carbon on the ring electrophilic. When the nitrogen atom is protonated, the electrophilicity of the carbon atom on the ring is enhanced, thereby enhancing its nucleophilic attack reaction activity against hydrogen sulfide and other nucleophilic reagents, thereby making the nitrogen compound a good hydrogen sulfide removal agent. Under the action of the electron-pushing group on the nitrogen atom, when the pH is 9.0 to 11.0, it can efficiently undergo a selective nucleophilic substitution reaction with H2S, and the main product generated is a thiadiazine compound, which is easily biodegradable and does not cause secondary pollution. In addition, the nitrogen compound does not react with CO2, which greatly reduces the amount of absorbent used when treating fuel gas and ensures the sulfur capacity of the absorbent. The addition of an activator can promote the activation of unhydrolyzed carbonyl sulfide and carbon disulfide, thereby increasing the reaction rate of the nitrogen compounds with unhydrolyzed carbonyl sulfide and carbon disulfide, and promoting the dissolution and absorption of unhydrolyzed carbonyl sulfide and carbon disulfide in the absorbent. The addition of a degradation inhibitor can significantly slow the degradation rate of nitrogen compounds at pH < 9, ensuring their continuous and efficient nucleophilic substitution reaction with hydrogen sulfide, thereby greatly broadening the pH range in which nitrogen compounds maintain high activity and increasing sulfur capacity.

[0042] 2. In the organic sulfur hydrolysis catalyst used in the method for treating sulfides in fuel gas provided by the present invention, activated alumina with a porosity greater than 0.7 is used as a carrier, which reduces sulfur deposition on the carrier surface, thereby ensuring good catalytic performance of the catalyst; the dual active components of the alkali metal and transition metal are loaded, which changes the acidity and alkalinity of the catalyst, not only increases the activity of the catalyst, but also greatly increases the hydrolysis performance of the catalyst at lower temperatures. Carbonyl sulfide and carbon disulfide in the fuel gas can be converted into hydrogen sulfide and carbon dioxide at temperatures less than 50°C (normal and low temperatures). The process is simple to operate, has a low reaction temperature, low energy consumption, does not consume a hydrogen source, and is easily absorbed by subsequent absorbents. Specifically, the organic sulfur hydrolysis catalyst can hydrolyze carbonyl sulfide and carbon disulfide into hydrogen sulfide and carbon dioxide at normal and low temperatures, 0.1 to 8.0 MPa. It is simple to operate, has no energy consumption, and is easily absorbed by subsequent absorbents.

[0043] 3. In the method for treating sulfides in fuel gas provided by the present invention, the low-concentration fuel gas containing mainly carbonyl sulfide and carbon disulfide is subjected to deep desulfurization treatment by combining normal and low-temperature organic sulfur hydrolysis with high-gravity absorption, and the sulfur content is reduced to 2 mg / m 3 The exhaust gas temperature of the heating furnace is reduced, the thermal efficiency of the heating furnace is improved, and the absorption liquid circulation volume and the energy consumption of the heating furnace are reduced, so that the investment cost and the operation cost are relatively low. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a front view of the organic sulfur hydrolysis tower used in Example 1 of the present invention;

[0045] Figure 2 2 is a cross-sectional view of the annular gas distribution pipe in the organic sulfur hydrolysis tower used in Example 1 of the present invention;

[0046] Figure 3 This is a schematic structural diagram of the hypergravity machine used in Example 1 of the present invention.

[0047] In the figure, 1. Air inlet pipe; 2. Drain pipe; 3. Annular air distribution pipe; 4. Fixed support plate with holes; 5. Annular sealing ring; 6. Manhole; 7. Organic sulfur hydrolysis catalyst; 8. Air outlet pipe; 9. Air distribution holes; 10. Gas inlet; 11. Liquid inlet; 12. Gas outlet; 13. Liquid outlet. DETAILED DESCRIPTION

[0048] The present invention is described in detail below by way of examples. It is necessary to point out that the following examples are only used to further illustrate the present invention and are not to be construed as limiting the scope of protection of the present invention. Those skilled in the art may make some non-essential improvements and adjustments to the present invention based on the above disclosure.

[0049] If no specific experimental steps or conditions are specified in the Examples and Comparative Examples, the conventional experimental steps or conditions described in the literature in the field can be used. If the manufacturer of the reagents or instruments is not specified, they are all commercially available conventional reagents.

[0050] Source of raw materials:

[0051] Acetic anhydride was purchased from Nanjing Oriental Pearl Industry and Trade Co., Ltd.;

[0052] Sodium EDTA was purchased from Hubei Shiteng Chemical Technology Co., Ltd.

[0053] Ethylenediaminetetraacetic acid was purchased from Shandong Longhui Chemical Co., Ltd.;

[0054] Acetic acid was purchased from Yangzhou Longfei Environmental Protection New Materials Co., Ltd.

[0055] Sodium acetate was purchased from Wuxi Xiongxiong Fine Technology Co., Ltd.;

[0056] The organosulfur hydrolysis catalyst was purchased from Liaoning Haitai Technology Development Co., Ltd.;

[0057] Methyldiethanolamine was purchased from Shandong Huibang New Material Technology Co., Ltd.;

[0058] 1,3,5-Tris(2-hydroxyethyl)-hexahydro-s-triazine was purchased from Tianjin Kewei Jinhong Co., Ltd.

[0059] The nitrogen compounds used in each embodiment were prepared according to the following method:

[0060] 1) Preparation of 1,3,5-trihydroxy-s-triazine

[0061]

[0062] Hydroxylamine hydrochloride was added to the formaldehyde solution at 0°C with stirring. After the addition was complete, the mixture was stirred at 0°C for 5 minutes and then warmed to room temperature. The mixture was stirred at room temperature for 2 hours. The reaction system was then concentrated under vacuum (10.67KPa, 40°C) to remove the solvent. 5mL of ethanol was then added to the concentrated residue, which was placed in a refrigerator at 4°C for 24 hours before being added with 10mL of ethanol. The solid matter was filtered out and dried under vacuum (26.67Pa, 25°C) to obtain 1,3,5-trihydroxy-s-triazine (TfOH3) as a white solid.

[0063] The structural characterization of TfOH3 is as follows: 1 H NMR (300MHz, HSQC, D2O) δ, ppm: 4.53 (s, 6H, 3CH2). 13 C NMR (75MHz, HSQC, D2O), δ, ppm: 74.3 (CH2).

[0064] ESI-HRMS m / z[M-Cl] + calcd for[C3H 10 N3O3] + :136.0717.Found:136.0718.

[0065] 2) Preparation of nitrogen compounds

[0066] After stirring an organic anhydride (formic anhydride, acetic anhydride, propionic anhydride, butyric anhydride, or isobutyric anhydride), TfOH3, and sulfuric acid at room temperature for 10 hours, the excess anhydride is evaporated under reduced pressure, and finally crystallized from ethyl acetate to obtain an acyloxy-type iso-nitrogen compound (the corresponding iso-nitrogen compounds were identified by NMR and MS and showed correct structures). The synthetic route is as follows:

[0067]

[0068] Example 1

[0069] This embodiment provides a method for treating sulfides in fuel gas, wherein the device used is an organic sulfur hydrolysis tower and a super gravity machine connected to each other. The organic sulfur hydrolysis tower is as follows: Figure 1 and Figure 2 As shown, the supergravity machine is as follows Figure 3 shown.

[0070] like Figure 1 and Figure 2 As shown, the organic sulfur hydrolysis tower has a fuel gas inlet (equipped with an air inlet pipe 1 equipped with a flow control valve) on its lower sidewall and an exhaust port (equipped with an air outlet pipe 8 equipped with a flow control valve) on its top. Inside, from top to bottom, are a fixed perforated support plate 4 and an annular air distribution pipe 3 formed by a series of concentric circles. An annular sealing ring 5 is installed between the fixed perforated support plate 4 and the inner wall of the organic sulfur hydrolysis tower. The annular air distribution pipe is provided with air distribution holes 9. An organic sulfur hydrolysis catalyst 7 is installed above the fixed perforated support plate 4. A manhole 6 is provided on the sidewall of the organic sulfur hydrolysis tower above the fixed perforated support plate 4 to facilitate catalyst installation and inspection and maintenance of the organic sulfur hydrolysis tower.

[0071] like Figure 3 As shown, the supergravity machine includes a drum cavity and an exchange cavity which are sequentially connected from top to bottom. A liquid inlet 11 is provided at the top of the drum cavity, a gas outlet 12 is provided on the top side wall, and a liquid distributor is provided inside; a liquid outlet 13 is provided at the bottom (non-center position) of the exchange cavity, a gas inlet 10 is provided on the side wall, a packing layer is located in the exchange cavity, and the exhaust port of the organic sulfur hydrolysis tower is connected to the gas inlet 10 on the exchange cavity of the supergravity machine.

[0072] The specific steps include:

[0073] 1) Dissolve the isocyanate compound (R' is -OCOCH3) in desalted water, then add the activator sodium ethylenediaminetetraacetate, stir evenly, add the degradation inhibitor acetic acid-sodium acetate (pH 5.3), and control the pH of the system to 10.95 to obtain a selective absorbent, which is placed in a storage tank for later use;

[0074] Calculated by mass percentage, the selective absorbent comprises 45 wt% of azo compounds, 0.5 wt% of sodium ethylenediaminetetraacetate, 2 wt% of acetic acid-sodium acetate, and 52.5 wt% of desalted water.

[0075] 2) At room temperature, the pressure is 0.7Mpa and the flow rate is 100m 3 / h of fuel gas enters from the fuel gas inlet on the lower side of the organic sulfur hydrolysis tower, and then flows from bottom to top, passing through a ring-shaped gas distribution pipe composed of a series of concentric circles, so that the fuel gas is fully and evenly contacted with the organic sulfur hydrolysis catalyst, and the carbonyl sulfide and carbon disulfide in the fuel gas are hydrolyzed to produce hydrogen sulfide and carbon dioxide, and the obtained mixed gas is discharged from the exhaust port on the top.

[0076] 3) The mixed gas discharged from the exhaust port at the top of the organic sulfur hydrolysis tower enters the supergravity absorption machine through the gas inlet on the bottom side wall of the exchange chamber under its own pressure. At the same time, the above-mentioned selective absorbent is pumped from the storage tank into the liquid inlet at the top of the drum chamber through a centrifugal pump, and then distributed on the packing layer of the exchange chamber through the liquid distributor. The packing is a stainless steel wire mesh with a specific surface area of ​​1100m 2 / m 3 The mixed gas and selective absorbent are heated at a high gravity factor of 40, an operating pressure of 0.68 MPa, and a liquid-gas ratio of 18 L / m 3 The selective absorbent after selectively absorbing hydrogen sulfide is discharged from the liquid outlet at the bottom of the exchange chamber to the absorbent storage tank, and the treated mixed gas is discharged from the gas outlet on the top side wall of the inner cavity of the drum to enter the heating furnace device.

[0077] Example 2

[0078] This embodiment provides a method for treating sulfides in fuel gas, using the same apparatus as in Example 1, and specifically comprising the following steps:

[0079] 1) Dissolve the isocyanate compound (the substituent R' is -OCOCH3) in desalted water, then add the activator ethylenediaminetetraacetic acid, stir evenly, add the degradation inhibitor acetic acid-sodium acetate (pH 5.3), and control the pH of the system to 9.36 to obtain a selective absorbent; place the mixture in a storage tank for later use;

[0080] Calculated by mass percentage, the selective absorbent comprises 55 wt% of iso-nitrogen compounds, 1.5 wt% of ethylenediaminetetraacetic acid, 3.5 wt% of acetic acid-sodium acetate, and 40 wt% of desalted water.

[0081] 2) At 40°C, the pressure is 0.7 MPa and the flow rate is 80 m 3 / h of fuel gas enters from the fuel gas inlet on the lower side of the organic sulfur hydrolysis tower, and then flows from bottom to top, passing through a ring-shaped gas distribution pipe composed of a series of concentric circles, so that the fuel gas is fully and evenly contacted with the organic sulfur hydrolysis catalyst, and the carbonyl sulfide and carbon disulfide in the fuel gas are hydrolyzed to produce hydrogen sulfide and carbon dioxide, and the obtained mixed gas is discharged from the exhaust port on the top.

[0082] 3) The mixed gas discharged from the exhaust port at the top of the organic sulfur hydrolysis tower enters the supergravity absorption machine through the gas inlet on the bottom side wall of the exchange chamber under its own pressure. At the same time, the above-mentioned selective absorbent is fed from the storage tank through the liquid inlet at the top of the drum chamber via a centrifugal pump and then distributed on the packing layer of the exchange chamber through the liquid distributor. The packing is a stainless steel wire mesh with a specific surface area of ​​1000m 2 / m 3 The mixed gas and selective absorbent are heated at a high gravity factor of 120, an operating pressure of 0.68 MPa, and a liquid-gas ratio of 18 L / m 3 The selective absorbent after selectively absorbing hydrogen sulfide is discharged from the liquid outlet at the bottom of the exchange chamber to the absorbent storage tank, and the treated fuel gas is discharged from the gas outlet on the top side wall of the drum cavity and enters the heating furnace device.

[0083] Example 3

[0084] This embodiment provides a method for treating sulfides in fuel gas, using the same apparatus as in Example 1, and specifically comprising the following steps:

[0085] 1) Dissolve the isocyanate compound (the substituent R' is -OCOCH3) in desalted water, then add the activator sodium ethylenediaminetetraacetate, stir evenly, add the degradation inhibitor acetic acid-sodium acetate (pH 5.3), and control the pH of the system to 10.23 to obtain a selective absorbent; place the mixture in a storage tank for later use;

[0086] Calculated by mass percentage, the selective absorbent comprises 45 wt% of azo compounds, 2 wt% of sodium ethylenediaminetetraacetate, 4 wt% of acetic acid-sodium acetate, and 49 wt% of desalted water.

[0087] 2) At room temperature, the pressure is 0.8Mpa and the flow rate is 50m 3 / h of fuel gas enters from the fuel gas inlet on the lower side of the organic sulfur hydrolysis tower, and then flows from bottom to top, passing through a ring-shaped gas distribution pipe composed of a series of concentric circles, so that the fuel gas is fully and evenly contacted with the organic sulfur hydrolysis catalyst, and the carbonyl sulfide and carbon disulfide in the fuel gas are hydrolyzed to produce hydrogen sulfide and carbon dioxide, and the obtained mixed gas is discharged from the exhaust port on the top.

[0088] 3) The mixed gas discharged from the exhaust port at the top of the organic sulfur hydrolysis tower enters the supergravity absorption machine through the gas inlet on the bottom side wall of the exchange chamber under its own pressure. At the same time, the above-mentioned selective absorbent is fed from the storage tank through the liquid inlet at the top of the drum chamber via a centrifugal pump and then distributed on the packing layer of the exchange chamber through the liquid distributor. The packing is a stainless steel wire mesh with a specific surface area of ​​1200m 2 / m 3 The mixed gas and selective absorbent are heated at a high gravity factor of 60, an operating pressure of 0.78 MPa, and a liquid-gas ratio of 18 L / m 3 Article

[0089] The selective absorbent after selectively absorbing hydrogen sulfide is discharged from the liquid outlet at the bottom of the exchange chamber to the absorbent storage tank, and the treated fuel gas is discharged from the gas outlet on the top side wall of the inner cavity of the drum to enter the heating furnace device.

[0090] Example 4

[0091] This embodiment provides a method for treating sulfides in fuel gas, using the same apparatus as in Example 1, and specifically comprising the following steps:

[0092] 1) Dissolve the isocyanate compound (the substituent R' is -OCOCH2CH3) in desalted water, then add the activator sodium ethylenediaminetetraacetate, stir evenly, add the degradation inhibitor acetic acid-sodium acetate (pH 5.3), and control the pH of the system to 10.87 to obtain a selective absorbent; place the mixture in a storage tank for later use;

[0093] Calculated by mass percentage, the selective absorbent comprises 58 wt% of iso-nitrogen compounds, 2 wt% of sodium ethylenediaminetetraacetate, 4 wt% of acetic acid-sodium acetate, and 36 wt% of desalted water.

[0094] 2) At 40°C, the pressure is 0.52 MPa and the flow rate is 90 m 3 / h of fuel gas enters from the fuel gas inlet on the lower side of the organic sulfur hydrolysis tower, and then flows from bottom to top, passing through a ring-shaped gas distribution pipe composed of a series of concentric circles, so that the fuel gas is fully and evenly contacted with the organic sulfur hydrolysis catalyst, and the carbonyl sulfide and carbon disulfide in the fuel gas are hydrolyzed to produce hydrogen sulfide and carbon dioxide, and the obtained mixed gas is discharged from the exhaust port on the top.

[0095] 3) The mixed gas discharged from the exhaust port at the top of the organic sulfur hydrolysis tower enters the supergravity absorption machine through the gas inlet on the bottom side wall of the exchange chamber under its own pressure. At the same time, the above-mentioned selective absorbent is pumped from the storage tank into the liquid inlet at the top of the drum chamber through a centrifugal pump, and then distributed on the packing layer of the exchange chamber through the liquid distributor. The packing is a stainless steel wire mesh with a specific surface area of ​​1100m 2 / m 3 The mixed gas and selective absorbent are heated at a high gravity factor of 60, an operating pressure of 0.5 MPa, and a liquid-gas ratio of 8 L / m 3 The selective absorbent after selectively absorbing hydrogen sulfide is discharged from the liquid outlet at the bottom of the exchange chamber to the absorbent storage tank, and the treated fuel gas is discharged from the gas outlet on the top side wall of the drum cavity and enters the heating furnace device.

[0096] Example 5

[0097] This embodiment provides a method for treating sulfides in fuel gas, using the same apparatus as in Example 1, and specifically comprising the following steps:

[0098] 1) Dissolve the isocyanate compound (the substituent R' is -OCOCH2CH3) in desalted water, then add the activator sodium ethylenediaminetetraacetate, stir evenly, add the degradation inhibitor acetic acid-sodium acetate (pH 5.3), and control the pH of the system to 9.93 to obtain a selective absorbent; place the mixture in a storage tank for later use;

[0099] Calculated by mass percentage, the selective absorbent comprises 45 wt% of azo compounds, 0.5 wt% of sodium ethylenediaminetetraacetate, 1.5 wt% of acetic acid-sodium acetate, and 53 wt% of desalted water.

[0100] 2) At room temperature, the pressure is 0.7Mpa and the flow rate is 80m 3 / h of fuel gas enters from the fuel gas inlet on the lower side of the organic sulfur hydrolysis tower, and then flows from bottom to top, passing through a ring-shaped gas distribution pipe composed of a series of concentric circles, so that the fuel gas is fully and evenly contacted with the organic sulfur hydrolysis catalyst, and the carbonyl sulfide and carbon disulfide in the fuel gas are hydrolyzed to produce hydrogen sulfide and carbon dioxide, and the obtained mixed gas is discharged from the exhaust port on the top.

[0101] 3) The mixed gas discharged from the exhaust port at the top of the organic sulfur hydrolysis tower enters the supergravity absorption machine through the gas inlet on the bottom side wall of the exchange chamber under its own pressure. At the same time, the above-mentioned selective absorbent is pumped from the storage tank into the liquid inlet at the top of the drum chamber through a centrifugal pump, and then distributed on the packing layer of the exchange chamber through the liquid distributor. The packing is a stainless steel wire mesh with a specific surface area of ​​1100m 2 / m3 The mixed gas and selective absorbent are heated at a high gravity factor of 40, an operating pressure of 0.68 MPa, and a liquid-gas ratio of 4 L / m 3 The selective absorbent after selectively absorbing hydrogen sulfide is discharged from the liquid outlet at the bottom of the exchange chamber to the absorbent storage tank, and the treated fuel gas is discharged from the gas outlet on the top side wall of the drum cavity and enters the heating furnace device.

[0102] Example 6

[0103] This embodiment provides a method for treating sulfides in fuel gas, using the same apparatus as in Example 1, and specifically comprising the following steps:

[0104] 1) Dissolve the isocyanate compound (the substituent R' is -OCOCH2CH3) in desalted water, then add the activator sodium ethylenediaminetetraacetate, stir evenly, add the degradation inhibitor acetic acid-sodium acetate (pH 5.3), and control the pH of the system to 9.36 to obtain a selective absorbent; place the mixture in a storage tank for later use;

[0105] Calculated by mass percentage, the selective absorbent comprises 60 wt% of a nitrogen compound, 1.8 wt% of ethylenediaminetetraacetic acid, 3.2 wt% of acetic acid-sodium acetate, and 35 wt% of desalted water.

[0106] 2) At 40°C, the pressure is 0.6 MPa and the flow rate is 90 m 3 / h of fuel gas enters from the fuel gas inlet on the lower side of the organic sulfur hydrolysis tower, and then flows from bottom to top, passing through a ring-shaped gas distribution pipe composed of a series of concentric circles, so that the fuel gas is fully and evenly contacted with the organic sulfur hydrolysis catalyst, and the carbonyl sulfide and carbon disulfide in the fuel gas are hydrolyzed to produce hydrogen sulfide and carbon dioxide, and the obtained mixed gas is discharged from the exhaust port on the top.

[0107] 3) The mixed gas discharged from the exhaust port at the top of the organic sulfur hydrolysis tower enters the supergravity absorption machine through the gas inlet on the bottom side wall of the exchange chamber under its own pressure. At the same time, the above-mentioned selective absorbent is fed from the storage tank through the liquid inlet at the top of the drum chamber via a centrifugal pump and then distributed on the packing layer of the exchange chamber through the liquid distributor. The packing is a stainless steel wire mesh with a specific surface area of ​​1000m 2 / m 3 The mixed gas and selective absorbent are in the condition of super gravity factor of 100, operating pressure of 0.6Mpa, liquid-gas ratio of 16L / m 3 The selective absorbent after selectively absorbing hydrogen sulfide is discharged from the liquid outlet at the bottom of the exchange chamber to the absorbent storage tank, and the treated fuel gas is discharged from the gas outlet on the top side wall of the drum cavity and enters the heating furnace device.

[0108] Example 7

[0109] This embodiment provides a method for treating sulfides in fuel gas, using the same apparatus as in Example 1, and specifically comprising the following steps:

[0110] 1) A nitrogen compound (the substituent R' is -OCOCH2CH2CH3) is dissolved in desalted water, and then an activator, sodium ethylenediaminetetraacetate, is added. After stirring evenly, a degradation inhibitor, acetic acid-sodium acetate (pH 5.3), is added, and the pH of the system is controlled to 10.16 to obtain a selective absorbent; the selective absorbent is placed in a storage tank for later use;

[0111] Calculated by mass percentage, the selective absorbent comprises 45 wt% of azo compounds, 0.5 wt% of ethylenediaminetetraacetic acid, 2 wt% of acetic acid-sodium acetate, and 52.5 wt% of desalted water.

[0112] 2) At room temperature, the pressure is 0.6Mpa and the flow rate is 80m 3 / h of fuel gas enters from the fuel gas inlet on the lower side of the organic sulfur hydrolysis tower, and then flows from bottom to top, passing through a ring-shaped gas distribution pipe composed of a series of concentric circles, so that the fuel gas is fully and evenly contacted with the organic sulfur hydrolysis catalyst, and the carbonyl sulfide and carbon disulfide in the fuel gas are hydrolyzed to produce hydrogen sulfide and carbon dioxide, and the obtained mixed gas is discharged from the exhaust port on the top.

[0113] 3) The mixed gas discharged from the exhaust port at the top of the organic sulfur hydrolysis tower enters the supergravity absorption machine through the gas inlet on the bottom side wall of the exchange chamber under its own pressure. At the same time, the above-mentioned selective absorbent is fed from the storage tank through the liquid inlet at the top of the drum chamber via a centrifugal pump and then distributed on the packing layer of the exchange chamber through the liquid distributor. The packing is a stainless steel wire mesh with a specific surface area of ​​1000m 2 / m 3 The mixed gas and selective absorbent have a liquid-gas ratio of 16L / m at a supergravity factor of 140 and an operating pressure of 0.58Mpa. 3 The selective absorbent after selectively absorbing hydrogen sulfide is discharged from the liquid outlet at the bottom of the exchange chamber to the absorbent storage tank, and the treated fuel gas is discharged from the gas outlet on the top side wall of the drum cavity and enters the heating furnace device.

[0114] Example 8

[0115] This embodiment provides a method for treating sulfides in fuel gas, using the same apparatus as in Example 1, and specifically comprising the following steps:

[0116] 1) Dissolve the isocyanate compound (the substituent R' is -OCOCH2CH2CH3) in desalted water, then add the activator sodium ethylenediaminetetraacetate, stir evenly, add the degradation inhibitor acetic acid-sodium acetate (pH 5.3), and control the pH of the system to 9.08 to obtain a selective absorbent; place the mixture in a storage tank for later use;

[0117] Calculated by mass percentage, the selective absorbent comprises 55 wt% of iso-nitrogen compounds, 1.5 wt% of sodium ethylenediaminetetraacetate, 3.5 wt% of acetic acid-sodium acetate, and 40 wt% of desalted water.

[0118] 2) At 40°C, the pressure is 0.8 MPa and the flow rate is 60 m 3 / h of fuel gas enters from the fuel gas inlet on the lower side of the organic sulfur hydrolysis tower, and then flows from bottom to top, passing through a ring-shaped gas distribution pipe composed of a series of concentric circles, so that the fuel gas is fully and evenly contacted with the organic sulfur hydrolysis catalyst, and the carbonyl sulfide and carbon disulfide in the fuel gas are hydrolyzed to produce hydrogen sulfide and carbon dioxide, and the obtained mixed gas is discharged from the exhaust port on the top.

[0119] 3) The mixed gas discharged from the exhaust port at the top of the organic sulfur hydrolysis tower enters the supergravity absorption machine through the gas inlet on the bottom side wall of the exchange chamber under its own pressure. At the same time, the above-mentioned selective absorbent is pumped from the storage tank into the liquid inlet at the top of the drum chamber through a centrifugal pump, and then distributed on the packing layer of the exchange chamber through the liquid distributor. The packing is a stainless steel wire mesh with a specific surface area of ​​1100m 2 / m 3 The mixed gas and selective absorbent are heated at a high gravity factor of 60, an operating pressure of 0.78 MPa, and a liquid-gas ratio of 6 L / m 3 The selective absorbent after selectively absorbing hydrogen sulfide is discharged from the liquid outlet at the bottom of the exchange chamber to the absorbent storage tank, and the treated fuel gas is discharged from the gas outlet on the top side wall of the drum cavity and enters the heating furnace device.

[0120] Example 9

[0121] This embodiment provides a method for treating sulfides in fuel gas, using the same apparatus as in Example 1, and specifically comprising the following steps:

[0122] Dissolve the isocyanate compound (the substituent R' is -OCOCH(CH3)2) in desalted water, then add the activator sodium ethylenediaminetetraacetate, stir evenly, add the degradation inhibitor acetic acid-sodium acetate (pH 5.3), and control the pH of the system to 9.93 to obtain a selective absorbent; place it in a storage tank for later use;

[0123] Calculated by mass percentage, the selective absorbent comprises 50 wt% of azo compounds, 1.5 wt% of ethylenediaminetetraacetic acid, 2.5 wt% of acetic acid-sodium acetate, and 46 wt% of desalted water.

[0124] 2) At room temperature, the pressure is 0.6Mpa and the flow rate is 100m 3 / h of fuel gas enters from the fuel gas inlet on the lower side of the organic sulfur hydrolysis tower, and then flows from bottom to top, passing through a ring-shaped gas distribution pipe composed of a series of concentric circles, so that the fuel gas is fully and evenly contacted with the organic sulfur hydrolysis catalyst, and the carbonyl sulfide and carbon disulfide in the fuel gas are hydrolyzed to produce hydrogen sulfide and carbon dioxide, and the obtained mixed gas is discharged from the exhaust port on the top.

[0125] 3) The mixed gas discharged from the exhaust port at the top of the organic sulfur hydrolysis tower enters the supergravity absorption machine through the gas inlet on the bottom side wall of the exchange chamber under its own pressure. At the same time, the above-mentioned selective absorbent is pumped from the storage tank into the liquid inlet at the top of the drum chamber through a centrifugal pump, and then distributed on the packing layer of the exchange chamber through the liquid distributor. The packing is a stainless steel wire mesh with a specific surface area of ​​1100m 2 / m 3 The mixed gas and selective absorbent are heated at a high gravity factor of 40, an operating pressure of 0.58 MPa, and a liquid-gas ratio of 4 L / m 3 The selective absorbent after selectively absorbing hydrogen sulfide is discharged from the liquid outlet at the bottom of the exchange chamber to the absorbent storage tank, and the treated fuel gas is discharged from the gas outlet on the top side wall of the drum cavity and enters the heating furnace device.

[0126] Example 10

[0127] This embodiment provides a method for treating sulfides in fuel gas, using the same apparatus as in Example 1, and specifically comprising the following steps:

[0128] 1) Dissolving a nitrogen compound (the substituent R' is -OCOCH(CH3)2) in desalted water, then adding an activator, sodium ethylenediaminetetraacetate, and stirring evenly. Then, adding a degradation inhibitor, acetic acid-sodium acetate (pH 5.3), and controlling the pH of the system to 10.98, to obtain a selective absorbent; and placing the mixture in a storage tank for later use;

[0129] Calculated by mass percentage, the selective absorbent comprises 45 wt% of azo compounds, 0.5 wt% of ethylenediaminetetraacetic acid, 2 wt% of acetic acid-sodium acetate, and 52.5 wt% of desalted water.

[0130] 2) At 40°C, the pressure is 0.6 MPa and the flow rate is 100 m 3 / h of fuel gas enters from the fuel gas inlet on the lower side of the organic sulfur hydrolysis tower, and then flows from bottom to top, passing through a ring-shaped gas distribution pipe composed of a series of concentric circles, so that the fuel gas is fully and evenly contacted with the organic sulfur hydrolysis catalyst, and the carbonyl sulfide and carbon disulfide in the fuel gas are hydrolyzed to produce hydrogen sulfide and carbon dioxide, and the obtained mixed gas is discharged from the exhaust port on the top.

[0131] 3) The mixed gas discharged from the exhaust port at the top of the organic sulfur hydrolysis tower enters the supergravity absorption machine through the gas inlet on the bottom side wall of the exchange chamber under its own pressure. At the same time, the above-mentioned selective absorbent is pumped from the storage tank into the liquid inlet at the top of the drum chamber through a centrifugal pump, and then distributed on the packing layer of the exchange chamber through the liquid distributor. The packing is a stainless steel wire mesh with a specific surface area of ​​1100m 2 / m 3 The mixed gas and selective absorbent are heated at a high gravity factor of 40, an operating pressure of 0.58 MPa, and a liquid-gas ratio of 4 L / m 3 The selective absorbent after selectively absorbing hydrogen sulfide is discharged from the liquid outlet at the bottom of the exchange chamber to the absorbent storage tank, and the treated fuel gas is discharged from the gas outlet on the top side wall of the drum cavity and enters the heating furnace device.

[0132] Example 11

[0133] This embodiment provides a method for treating sulfides in fuel gas. The device used is the same as that in Example 1, and the specific steps and operating parameters are the same as those in Example 1. The difference is that the effect of this embodiment is the result obtained by analyzing and evaluating the absorbent in Example 1 after continuous operation for one month.

[0134] Comparative Example 1

[0135] The method for treating sulfides in fuel gas provided in this comparative example is similar to that in Example 1, except that a different selective absorbent is used. The preparation method of the selective absorbent used in this comparative example is as follows:

[0136] 1) dissolving methyldiethanolamine (MDEA) in desalted water, then adding an activator, sodium ethylenediaminetetraacetate, stirring evenly, adding a degradation inhibitor, acetic acid-sodium acetate, and controlling the pH value of the system to 10.95 to obtain a selective absorbent; and setting aside.

[0137] Calculated by mass percentage, the selective absorbent comprises 45 wt% of methyldiethanolamine, 0.5 wt% of sodium ethylenediaminetetraacetate, 2 wt% of acetic acid-sodium acetate, and 52.5 wt% of desalted water.

[0138] Comparative Example 2

[0139] This comparative example is similar to comparative example 1, except that the step of hydrolyzing carbonyl sulfide and carbon disulfide in the fuel gas to generate hydrogen sulfide and carbon dioxide in the organic sulfur hydrolysis tower is omitted. Figure 2 The specific steps of the hypergravity machine shown in this comparative example are as follows:

[0140] 1) dissolving methyldiethanolamine (MDEA) in desalted water, then adding an activator, sodium ethylenediaminetetraacetate, stirring evenly, adding a degradation inhibitor, acetic acid-sodium acetate, and controlling the pH value of the system to 10.95 to obtain a selective absorbent; and setting aside;

[0141] Calculated by mass percentage, the selective absorbent comprises 45 wt% of methyldiethanolamine, 0.5 wt% of sodium ethylenediaminetetraacetate, 2 wt% of acetic acid-sodium acetate, and 52.5 wt% of desalted water.

[0142] 2) At room temperature, the pressure is 0.7Mpa and the flow rate is 100m 3 / h fuel gas enters the supergravity absorption machine from the gas inlet on the bottom side wall of the exchange chamber. At the same time, the above selective absorbent enters the liquid inlet on the top of the drum chamber from the storage tank through a centrifugal pump and is then distributed on the packing layer of the exchange chamber through a liquid distributor. The packing is a stainless steel wire mesh with a specific surface area of ​​1100m 2 / m 3 The mixed gas and selective absorbent are heated at a high gravity factor of 40, an operating pressure of 0.7 MPa, and a liquid-gas ratio of 18 L / m 3 The selective absorbent after selectively absorbing hydrogen sulfide is discharged from the liquid outlet at the bottom of the exchange chamber to the absorbent storage tank, and the treated fuel gas is discharged from the gas outlet on the top side wall of the drum cavity and enters the heating furnace device.

[0143] Comparative Example 3

[0144] This comparative example is similar to Example 1, except that a different selective absorbent is used. The preparation method of the selective absorbent used in this comparative example is as follows:

[0145] 1) dissolving 1,3,5-tris(2-hydroxyethyl)-hexahydro-s-triazine in desalted water, then adding an activator, sodium ethylenediaminetetraacetate, stirring evenly, adding a degradation inhibitor, acetic acid-sodium acetate, and controlling the pH value of the system to 10.95 to obtain a selective absorbent; and setting aside.

[0146] Calculated by mass percentage, the selective absorbent comprises 45 wt% of 1,3,5-tris(2-hydroxyethyl)-hexahydro-s-triazine, 0.5 wt% of sodium ethylenediaminetetraacetate, 2 wt% of acetic acid-sodium acetate, and 52.5 wt% of desalted water.

[0147] Effect evaluation

[0148] Fuel gas before and after treatment in each example and comparative example was sampled from the fuel gas inlet on the lower side of the organic sulfur hydrolysis tower and the gas outlet on the top sidewall of the drum chamber of the high-gravity machine in accordance with standard HJ 732-2014. The carbonyl sulfide, carbon disulfide, and total sulfur contents were determined by gas chromatography according to GB / T 13610-2014. The carbon dioxide content was determined according to the "Determination of Carbon Dioxide in Waste Gas from Stationary Sources - Non-Dispersive Infrared Absorption Method" (HJ870-2017). The results are shown in the table below.

[0149] Table 1

[0150]

[0151] From the data in the above table, it can be seen that after deep desulfurization of the fuel gas from the refinery using the hydrogen sulfide selective absorbent provided by the present invention, the total sulfur content is reduced to 2 mg / m 3 Below, and the total sulfur content can still be reduced to 2mg / m after the absorbent is used continuously for one month 3 Under the same conditions, the treatment effect is better than that of using 1,3,5-tris(2-hydroxyethyl)-hexahydro-s-triazine instead of the selective absorbent composed of the iso-nitrogen compound in the present invention; while the total sulfur content cannot be reduced to 2 mg / m after treatment with MDEA alone or organic sulfur hydrolysis combined with MDEA. 3 the following.

[0152] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art may make various corresponding changes and modifications based on the present invention, but these corresponding changes and modifications should all fall within the scope of protection of the claims of the present invention.

Claims

1. A selective absorbent for hydrogen sulfide, characterized in that: The composition comprises the following components by mass percentage: 40% to 60% of azo compounds, 0.5% to 2.0% of an activator, 1.5% to 4.0% of a degradation inhibitor and the balance of water; The isocyanate compound has the following structure: Wherein, R' is selected from -OCOR, wherein R is selected from C1-C3 straight chain or branched alkyl.

2. The selective absorbent for hydrogen sulfide according to claim 1, characterized in that: R' is selected from any one of -OCOCH3, -OCOCH2CH3, -OCOCH2CH2CH3, and -OCOCH(CH3)2.

3. The selective absorbent for hydrogen sulfide according to claim 1, characterized in that: The activator is selected from ethylenediaminetetraacetic acid or sodium ethylenediaminetetraacetate; The degradation inhibitor is an acetic acid-sodium acetate buffer solution with a pH of 5.0 to 5.

5.

4. A method for preparing a selective absorbent for hydrogen sulfide according to any one of claims 1 to 3, characterized in that: The steps include: The iso-nitrogen compound is dissolved in water, and then an activator and a degradation inhibitor are added in sequence to obtain the selective absorbent for hydrogen sulfide.

5. A method for treating sulfide in fuel gas, characterized in that: The steps include: 1) At a temperature of less than 50°C and under the action of an organic sulfur hydrolysis catalyst, carbonyl sulfide and carbon disulfide in the fuel gas are hydrolyzed into hydrogen sulfide and carbon dioxide to obtain a mixed gas; 2) using a desulfurizing agent to selectively absorb hydrogen sulfide in the mixed gas without absorbing carbon dioxide under the action of supergravity to obtain treated fuel gas; Wherein, the desulfurizing agent is selected from the selective absorbent for hydrogen sulfide according to any one of claims 1-4.

6. The method for treating sulfide in fuel gas according to claim 5, characterized in that: The organic sulfur hydrolysis catalyst comprises a carrier and an active component, wherein the carrier comprises active alumina with a porosity greater than 0.7, and the active component comprises an alkali metal and a transition metal.

7. The method for treating sulfide in fuel gas according to claim 5, characterized in that: Step 1) is carried out in an organic sulfur hydrolysis tower.

8. The method for treating sulfide in fuel gas according to claim 7, characterized in that: Step 2) is carried out in a supergravity absorption device with a packing layer, and the organic sulfur hydrolysis tower is connected to the supergravity absorption device; The filler of the packing layer is a regular stainless steel wire mesh filler or a stainless steel corrugated plate filler; preferably, the filler is a regular stainless steel wire mesh filler.

9. The method for treating sulfide in fuel gas according to claim 8, characterized in that: The mixed gas contacts the desulfurizing agent in reverse direction in the packing layer.

10. The method for treating sulfide in fuel gas according to claim 9, characterized in that: The conditions of the reverse contact are as follows: the supergravity factor is 30-150, the operating pressure is 0.5-0.8 MPa, and the liquid-gas ratio is 2.0-20.0 L / m 3 .

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