Method for recovering sulfur by low-temperature photocatalysis Claus and photocatalyst
阅读说明：本技术 一种低温光催化克劳斯回收硫的方法及光催化剂 (Method for recovering sulfur by low-temperature photocatalysis Claus and photocatalyst ) 是由 王学谦 吴优 王郎郎 李翔 袁礼 蔡君 于 2021-09-15 设计创作，主要内容包括：本发明公开了一种低温光催化克劳斯回收硫的方法及光催化剂,采用TiO-(2)或TiO-(2)的复合氧化物为载体、负载金属氧化物活性组分及碱金属盐助剂,作为新型光催化剂进行低温光催化克劳斯反应回收硫；光照、催化剂同时存在条件下,对过程气进行光催化克劳斯反应和水解反应,将有机硫充分水解为无机硫,进一步发生低温克劳斯反应,从而提高克劳斯活性,以及水解效率,减少运行成本。该催化剂在低温光照条件下实现克劳斯硫磺回收,且对于有机硫与无机硫等气体具有高效的催化转化效率,催化剂在克劳斯反应中具有突出的效果,催化剂效率高,硫容高,有较高的性价。(The invention discloses a method for recovering sulfur by low-temperature photocatalysis Claus and a photocatalyst, which adopt TiO 2 Or TiO 2 The composite oxide is a carrier, a loaded metal oxide active component and an alkali metal salt auxiliary agent, and is used as a novel photocatalyst for carrying out low-temperature photocatalytic Claus reaction to recover sulfur; under the condition that illumination and a catalyst exist simultaneously, the process gas is subjected to photocatalytic Claus reaction and hydrolysis reaction, organic sulfur is fully hydrolyzed into inorganic sulfur, and low-temperature Claus reaction is further performed, so that Claus activity is improved, hydrolysis efficiency is improved, and operation cost is reduced. TheThe catalyst realizes the recovery of Claus sulfur under the condition of low-temperature illumination, has high catalytic conversion efficiency on organic sulfur, inorganic sulfur and other gases, has outstanding effect in Claus reaction, and has high efficiency, high sulfur capacity and higher cost performance.)
1. A method for recovering sulfur by low-temperature photocatalysis Claus is characterized by comprising the following steps;
the method comprises the following steps: thermal reaction stage
Will contain H2Sour gas and O of S2Introducing into a combustion furnace, performing Claus combustion reaction at 1000-1200 deg.C to obtain part of H2S and O2Reaction to form SO2SO formed by the reaction2With the remainder of H2S is subjected to a Claus reaction to generate elemental sulfur, and after the reaction is finished, the elemental sulfur is introduced into a waste heat boiler to be cooled to 350 ℃ and heat energy is recovered, thenThen enters a first-stage condenser to separate liquid sulfur at the temperature of 150 ℃ and 180 ℃ and the rest process gas is left;
step two: stage of catalytic reaction
(2.1) conventional Claus reaction: heating the process gas generated by the primary condenser in the step one to 210-;
(2.2) sub-dew point low temperature Claus reaction: the process gas generated by the secondary condenser in the step (2.1) enters a secondary Claus reactor for photocatalytic sub-dew point low-temperature Claus reaction at the temperature of 110-140 ℃, the liquid elemental sulfur generated after the reaction is gasified and desorbed in a catalyst regeneration mode, and enters a tertiary condenser together with the rest gas for condensation to 70-100 ℃, liquid sulfur is separated, and the rest process gas is left;
(2.3) a sub-solid point low-temperature Claus reaction: the process gas generated by the three-stage condenser enters a three-stage Claus reactor to carry out photocatalytic sub-solid point low-temperature Claus reaction at the temperature of 60-100 ℃ to generate elemental sulfur, including solid elemental sulfur, liquid elemental sulfur and gaseous elemental sulfur;
(2.4) product separation: and (3) gasifying and desorbing the solid elemental sulfur and the liquid elemental sulfur generated in the step (2.3) in a catalyst regeneration mode, introducing the gasified and desorbed elemental sulfur and the gaseous elemental sulfur into a four-stage condenser together, separating liquid sulfur at 70-100 ℃, and burning the separated tail gas in a burning furnace and then discharging.
2. The method of claim 1, wherein in step one, the amount of oxygen is controlled so that the molar ratio of sulfur dioxide produced by the reaction to the remaining hydrogen sulfide is 1: 2.
3. The method for recycling sulfur through low-temperature photocatalytic Claus as claimed in claim 1, wherein the catalyst regeneration in step two is performed by gasifying and removing liquid or solid elemental sulfur adsorbed in the catalyst in a heating manner, wherein the heating temperature is 300-400 ℃.
4. A low temperature photocatalytic claus sulfur recovery method according to claim 1, characterized by that, the photocatalysis in step (2.2) and step (2.3) is ultraviolet light or visible light, the wavelength of ultraviolet light is 185nm or 365 nm.
5. The low temperature photocatalytic claus sulfur recovery photocatalyst of claim 1, comprising the following components in weight percent:
50-90 wt% of carrier, 10-40 wt% of active component and 1-10 wt% of cocatalyst;
the carrier is titanium dioxide;
the active component is one or more of ferric oxide, copper oxide, zinc oxide, cobalt oxide, cerium oxide, zirconium oxide, magnesium oxide, aluminum oxide and lanthanum oxide;
the cocatalyst is one or more of alkali metal salt, inorganic sodium salt, inorganic potassium salt, organic sodium salt and organic potassium salt.
6. A method for preparing the low-temperature photocatalytic Claus sulfur recovery photocatalyst according to claim 5, characterized by comprising the following steps:
(1) dissolving active components in deionized water, stirring in dark for 5-30min, adding titanium tetrachloride, stirring vigorously, and adding dropwise NH3·H2The O solution forms a precipitate, and the dripping is stopped when the pH value reaches 9.0-10;
(2) diluting the mixture obtained in the step (1) with deionized water, then violently stirring in a water bath at 50 ℃ for 30-60min, and then standing to remove supernatant liquid to obtain a precipitate;
(3) washing the precipitate obtained in the step (2) with deionized water for 3-5 times, drying at 40-100 ℃ for 8-24h, crushing, calcining at 500 ℃ for 1-3h under a nitrogen atmosphere to obtain crystalline anatase, and calcining at 300 ℃ for 2-3h under an oxygen atmosphere to obtain titanium dioxide loaded with active components;
(4) weighing a cocatalyst, dissolving the cocatalyst in deionized water, weighing the titanium dioxide loaded with the active component prepared in the step (3), placing the titanium dioxide in the deionized water, soaking for 12-24h, filtering, and drying at 60-100 ℃ for 6-12h to prepare the photocatalyst for recovering sulfur by using the warm-light catalysis Claus.
7. The method for preparing the photocatalyst for recovering the sulfur by the low-temperature photocatalytic Claus as claimed in claim 6, wherein the active component precursor in the step (1) is a chloride or a nitrate corresponding to the active component.
8. The method for preparing the photocatalyst for recovering the sulfur by the low-temperature photocatalytic Claus according to claim 6, wherein the molar ratio of the active component precursor to the deionized water in the step (1) is 1.7: 1.
9. The method for preparing the photocatalyst for recovering sulfur by low-temperature photocatalytic Claus as claimed in claim 6, wherein the NH in the step (1)3·H2The volume concentration of the O solution is 25 percent.
10. The method for preparing the photocatalyst for recovering sulfur by low-temperature photocatalytic Claus as claimed in claim 6, wherein the vigorous stirring rotation speed in the steps (1) and (2) is 1500r/min and 2600r/min respectively.
Technical Field
The invention relates to the technical field of gas treatment chemical industry, in particular to a method for recovering sulfur by low-temperature photocatalysis Claus and a photocatalyst.
Background
The Claus process is an efficient process for treating H2S and other acidic gases and sulfur recovery. The process controls the oxygen input to 1/3H2S gas is oxidized into SO2SO formed2And H2S is produced by the Claus reaction in the catalytic reactor to generate sulfur vapor, and finally sulfur is recovered. Most advanced sulfur recovery processes are perfected and developed on the basis of classical claus sulfur recovery processes, such as oxygen-rich claus processes, super claus processes, scott processes, biological desulfurization processes, low temperature claus processes, etc. Among them, the low-temperature Claus technology, also called sub-dew point sulfur recovery technology, is one of the widely applied sulfur recovery and tail gas treatment technology types, and is mainly characterized by performing Claus reaction at a temperature lower than the dew point temperature of sulfur.
The main low-temperature Claus sulfur recovery processes comprise MCRC, CBA, Clinsuf-SDP, Sulfreen and Claus pol, and CPS process developed by China Petroleum institute; however, these processes all have certain disadvantages. The low-temperature Claus sulfur recovery process such as CBA, MCRC and Clinsuf-SDP has the disadvantages that liquid sulfur is easy to accumulate on a catalyst in the low-temperature adsorption reaction process, so that the catalyst is deactivated, and the corresponding equipment structure is complex, the investment is large and the sulfur recovery rate is low. The claus process is complicated, the catalyst is easily deactivated and the conversion rate is low due to thermodynamic and kinetic limitations of the claus reaction and hydrolysis influence of other sulfur species in the gas in the reaction process. From the technical and economic aspects, aiming at the limitation of the low-temperature Claus sulfur recovery process, the method provides a new low-temperature photocatalytic Claus method and an excellent catalyst with complete functions, is the most effective countermeasure and measure, and is an effective way for saving the device investment and improving the technical level of the sulfur recovery process.
Since the industrialization of the modified claus process, sulfur recovery catalysts have undergone roughly three stages of development. The first stage is the natural bauxite catalyst stage. The original Claus catalyst used natural bauxite, its advantages are simple process and low cost. But also has some defects of poor mechanical strength, easy pulverization, incapability of catalytically converting organic sulfur in acid gas, about 80 percent of sulfur recovery rate, and burning various unconverted sulfides by SO2The air is discharged into the atmosphere, and the environment is seriously polluted. The second stage is the activated alumina stage. The activated alumina catalyst has higher conversion and mechanical strength than the claus catalyst of the first stage. But also has some corresponding problems, such as easy sulfation, "oxygen leakage" poisoning, less than 80% of organic sulfur conversion effect, about 70% of claus activity, serious influence on the total sulfur recovery rate of the sulfur recovery device and the up-to-standard tail gas emission, and large bed resistance. The third stage is a stage of using the multi-type catalyst together. Since pure activated alumina catalysts have limited activity and are deactivated by "oxygen leakage" which sulfatizes the Claus catalyst, the catalyst used in the third stage is generally Fe with added sulfation-resistant and cocatalytic activity2O3And/or TiO2A composite catalyst. The catalyst is characterized in that: promoting Claus reaction, and has the functions of resisting sulfation, resisting oxygen leakage, promoting organic sulfur hydrolysis, etc. But the comprehensive application of the existing composite catalyst in the aspects of sulfation resistance, oxygen leakage protection, reaction energy consumption reduction and catalytic efficiency has obvious defects, so that the research on the low-temperature catalyst of the high-efficiency Claus process has great significance.
JP58223440 discloses a catalyst for recovering Claus sulphur, which is prepared by kneading, grinding, compression molding and granulating 80-97 wt% of titanium dioxide as an active component and 20-30 wt% of inert aluminosilicate as a reinforcing material. The Claus sulfur recovery rate of the catalyst is only about 90%, and SO in tail gas2The content is also higher.
CN200710111295.X discloses an acid-containing agentA catalyst for recovering Claus sulfur from gas and a preparation method thereof. The catalyst is composed of 65-85 wt% of titanium dioxide, 10-30 wt% of aluminosilicate with a layered structure and 1-5 wt% of ammonium sulfate. The catalyst has stronger hydrolytic activity of organic sulfide and Claus reaction activity, and has certain O leakage resistance2And the hydrolysis capability and the Claus benefit of COS are also better. However, inert aluminosilicate is used as a reinforcing material, and the catalyst is prepared through processes of filter pressing, powder pressing, kneading and the like, so that the Claus activity is only 80%, and the organic sulfur hydrolysis efficiency is only 60%.
In view of the above problems, a need to solve the above problems is felt by those skilled in the art to provide a new low-temperature photocatalytic claus process and an excellent fully functional catalyst.
Disclosure of Invention
In view of this, the present invention provides a catalyst for recovering sulfur by low-temperature photocatalysis claus and a recovery method thereof, aiming at the limitation of the low-temperature claus sulfur recovery process. Not only can effectively hydrolyze H in the low-temperature Claus process2S and organic sulfur, and realizes resource utilization of sulfur.
In order to achieve the purpose, the invention adopts the following technical scheme:
a method for recovering sulfur by low-temperature photocatalysis Claus comprises the following steps;
the method comprises the following steps: thermal reaction stage
Will contain H2Sour gas and O of S2Introducing into a combustion furnace, performing Claus combustion reaction at 1000-1200 deg.C to obtain part of H2S and O2Reaction to form SO2SO formed by the reaction2With the remainder of H2S, performing a Claus reaction to generate elemental sulfur, introducing the elemental sulfur into a waste heat boiler after the reaction is finished, cooling to 350 ℃, recovering heat energy, then introducing the elemental sulfur into a primary condenser, separating liquid sulfur at 180 ℃, and remaining process gas;
step two: stage of catalytic reaction
(2.1) conventional Claus reaction: heating the process gas generated by the primary condenser in the step one to 210-;
(2.2) sub-dew point low temperature Claus reaction: the process gas generated by the secondary condenser in the step (2.1) enters a secondary Claus reactor for photocatalytic sub-dew point low-temperature Claus reaction at the temperature of 110-140 ℃, the liquid elemental sulfur generated after the reaction is gasified and desorbed in a catalyst regeneration mode, and enters a tertiary condenser together with the rest gas for condensation to 70-100 ℃, liquid sulfur is separated, and the rest process gas is left;
(2.3) a sub-solid point low-temperature Claus reaction: the process gas generated by the three-stage condenser enters a three-stage Claus reactor to carry out photocatalytic sub-solid point low-temperature Claus reaction at the temperature of 60-100 ℃ to generate elemental sulfur, including solid elemental sulfur, liquid elemental sulfur and gaseous elemental sulfur;
(2.4) product separation: and (3) gasifying and desorbing the solid elemental sulfur and the liquid elemental sulfur generated in the step (2.3) in a catalyst regeneration mode, introducing the gasified and desorbed elemental sulfur and the gaseous elemental sulfur into a four-stage condenser together, separating liquid sulfur at 70-100 ℃, and burning the separated tail gas in a burning furnace and then discharging.
Preferably, in the first step, the oxygen amount is controlled so that the molar ratio of the sulfur dioxide generated by the reaction to the residual hydrogen sulfide is 1: 2.
Preferably, the catalyst regeneration in the second step is to gasify and remove the liquid or solid elemental sulfur adsorbed in the catalyst in a heating manner, and the heating temperature is 300-400 ℃.
Preferably, the photocatalysis in step (2.2) and step (2.3) is ultraviolet light or visible light, and the wavelength of the ultraviolet light is 185nm or 365 nm.
The reaction equipment of the technical scheme comprises a combustion furnace, a waste heat boiler, a heater, a primary condenser, a primary Claus reactor, a secondary condenser, a secondary Claus reactor, a tertiary condenser, a tertiary Claus reactor, a four-stage condenser, a tail gas incinerator and a chimney which are connected in sequence;
the first-stage Claus reactor, the second-stage Claus reactor and the third-stage Claus reactor realize catalyst regeneration and Claus reactions at different temperatures by program control valve circulation.
The invention also provides a photocatalyst for recovering sulfur by low-temperature photocatalysis Claus, which comprises the following components in percentage by weight:
50-90 wt% of carrier, 10-40 wt% of active component and 1-10 wt% of cocatalyst;
the carrier is titanium dioxide;
the active component is one or more of ferric oxide, copper oxide, zinc oxide, cobalt oxide, cerium oxide, zirconium oxide, magnesium oxide, aluminum oxide and lanthanum oxide;
the cocatalyst is one or more of alkali metal salt, inorganic sodium salt, inorganic potassium salt, organic sodium salt and organic potassium salt.
The preparation method of the photocatalyst for recovering sulfur by low-temperature photocatalysis Claus comprises the following steps:
(1) dissolving active components in deionized water, stirring in dark for 5-30min, adding titanium tetrachloride, stirring vigorously, and adding dropwise NH3·H2The O solution forms a precipitate, and the dripping is stopped when the pH value reaches 9.0-10;
(2) diluting the mixture obtained in the step (1) with deionized water, then violently stirring in a water bath at 50 ℃ for 30-60min, and then standing to remove supernatant liquid to obtain a precipitate;
(3) washing the precipitate obtained in the step (2) with deionized water for 3-5 times, drying at 40-100 ℃ for 8-24h, crushing, calcining at 500 ℃ for 1-3h under a nitrogen atmosphere to obtain crystalline anatase, and calcining at 300 ℃ for 2-3h under an oxygen atmosphere to obtain titanium dioxide loaded with active components;
(4) weighing a cocatalyst, dissolving the cocatalyst in deionized water, weighing the titanium dioxide loaded with the active component prepared in the step (3), placing the titanium dioxide in the deionized water, soaking for 12-24h, filtering, and drying at 60-100 ℃ for 6-12h to prepare the photocatalyst for recovering sulfur by using the warm-light catalysis Claus.
Preferably, the active component precursor in step (1) is a chloride or a nitrate corresponding to the active component.
Preferably, the molar ratio of the active component precursor to the deionized water in the step (1) is 1.7: 1.
Preferably, the NH described in step (1)3·H2The volume concentration of the O solution is 25 percent.
Preferably, the rotation speed of the vigorous stirring in the step (1) and the step (2) is 1500r/min and 2600r/min respectively.
Compared with the prior art, the invention discloses a method for recovering sulfur by low-temperature photocatalysis Claus and a photocatalyst, and the method has the following beneficial effects:
the Claus reaction is exothermic, and the reduction of the temperature is beneficial to moving the reaction equilibrium to the direction of generating sulfur, so that the sulfur recovery rate is improved. Titanium dioxide has photocatalytic oxidation performance, metal oxides such as iron, copper, cobalt and the like have high catalytic activity on organic sulfur, and the oxygen leakage protection capability is good, the metal oxides and alkali metal salt form a novel Claus process low-temperature catalyst of binary oxide magnetic nanoparticles, the catalyst combines catalytic hydrolysis and photocatalytic effects, organic sulfur can be effectively hydrolyzed, strong oxidizing substances such as hydroxyl radicals and the like can be generated by reaction under the illumination condition, alkaline sites on the surface of the catalyst are increased, and the organic sulfur is oxidized, so that the poisoning phenomenon of the hydrolysis catalyst caused by oxygen is effectively avoided, and the components such as Fe, Co, Ti and the like are common active components of the oxygen leakage protection catalyst, the titanium base has strong hydrolytic activity and strong sulfate resistance capability, so that the catalyst has high activity in the aspect of organic sulfur photocatalytic hydrolysis, and has a prominent effect on Claus reaction activity, the service life is longer. For low temperature claus catalysts, the pore structure of the catalyst has a significant impact on the efficiency of the low temperature claus reaction. The catalyst has high macroporous volume to ensure the conversion rate of catalytic reaction, high small pore volume to increase the specific surface area of the catalyst, good photoresponse effect, capability of performing photocatalysis at low temperature, reduced industrial energy consumption, organic sulfur photocatalytic hydrolysis rate up to 100%, Claus activity up to about 95%, and leak resistance2"poisoning Properties", Low-temperature photocatalytic Claus reaction based on this catalystAnd has higher economic benefit.
The low-temperature photocatalysis Claus sulfur recovery method provided by the invention adopts the additional lamp source in the low-temperature Claus reactor, combines the traditional sub-dew point Claus catalytic reaction or sub-solid point Claus catalytic reaction with the photocatalysis reaction, enables the Claus catalytic reaction to react at lower temperature, reduces the energy consumption, and has higher conversion rate and total sulfur recovery rate. The process flow is simple, the operation cost is low, and the environmental benefit is good. The catalyst can realize high-efficiency Claus gas photocatalytic hydrolysis at low temperature, has a strong oxygen leakage protection function, can remove trace oxygen in process gas, is weak in sulfation condition, has Claus efficiency of over 90 percent and hydrolysis efficiency of over 95 percent, and has long service life and high environmental benefit.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
FIG. 1 is a flow diagram of the low temperature photocatalytic Claus sulfur recovery process of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
γ-Fe2O3-K/TiO2Preparation of the photocatalyst:
(1) in weight percentFirstly, dissolving 40 percent of ferric trichloride of active component and deionized water in a molar ratio of 1.7:1 mutually, placing the mixture in a dark place for magnetic stirring for 5min, and adding 2ml of titanium tetrachloride (TiCl)4) 25% NH was added using a syringe pump under vigorous stirring3·H2The O solution is added into the solution dropwise, then a precipitate is formed, and when the pH value reaches 9.0, the addition of NH is stopped3·H2O solution;
(2) diluting to 200mL with deionized water, vigorously stirring in 50 deg.C water bath for 30min, standing for 30min, pouring out supernatant, and performing solid-liquid separation;
(3) washing with deionized water for 5 times after separation, drying for 8h at 100 ℃, finally crushing, calcining for 1h at 300 ℃ under the atmosphere of nitrogen to obtain crystalline anatase, and calcining for 2h at 250 ℃ under the atmosphere of oxygen to obtain titanium dioxide loaded with an active component, namely ferric oxide;
(4) preparing a cocatalyst component solution: weighing inorganic potassium salt according to the loading capacity of the catalyst, and dissolving the inorganic potassium salt in deionized water to prepare a salt solution of a KOH cocatalyst component with the mass concentration of 5%;
impregnation loading of the co-catalyst component: weighing titanium dioxide loaded with an active component ferric oxide, adding a prepared cocatalyst component solution according to the equal solid-to-liquid ratio of 1:5, soaking for 24h, and drying at 60 ℃ for 6h to obtain gamma-Fe2O3-K/TiO2A photocatalyst.
The obtained gamma-Fe2O3-K/TiO2The photocatalyst is used for carrying out catalytic evaluation on the catalyst in a low-temperature photocatalytic Claus reaction device, the experiment is carried out in a low-temperature photocatalytic Claus reactor at the temperature of 90 ℃, and H with lower concentration is introduced2S、SO2Evaluation of Activity by simulating Claus acid gas, H2S concentration is 10000ppm, SO25000ppm, N2In order to balance gas, the Claus acid gas is subjected to photocatalysis and hydrolysis reaction under the conditions of ultraviolet irradiation (the wavelength of an ultraviolet lamp is 185nm) and the simultaneous existence of a catalyst. The final hydrolysis activity was 100%, the claus activity was 95%, and the sulfur recovery was 99.5%.
Example 2
CrO2-K/TiO2/Al2O3Preparation of the photocatalyst:
(1) according to weight percentage, firstly, 15 percent of zirconium nitrate and 15 percent of aluminum nitrate as active components are mutually dissolved with deionized water according to the molar ratio of 1.7:1, the mixture is placed in a dark place for magnetic stirring for 5min, and 2ml of titanium tetrachloride (TiCl) is added4) 25% NH was added using a syringe pump under vigorous stirring3·H2Adding O solution dropwise into the solution, forming precipitate, and stopping adding NH when pH reaches 10.03·H2O solution;
(2) diluting to 250mL with deionized water, vigorously stirring in 50 deg.C water bath for 60min, standing for 20min, pouring out supernatant, and performing solid-liquid separation;
(3) washing with deionized water for 4 times after separation, drying for 12h at 100 ℃, finally crushing, calcining for 3h at 500 ℃ in a nitrogen atmosphere to obtain crystalline anatase, and calcining for 2h at 250 ℃ in an oxygen atmosphere to obtain titanium dioxide loaded with active components of zirconium oxide and aluminum oxide;
(4) preparing a cocatalyst component solution: weighing inorganic potassium salt according to the loading capacity of the catalyst, and dissolving the inorganic potassium salt in deionized water to prepare a salt solution of a KOH cocatalyst component with the mass concentration of 5%;
impregnation loading of the co-catalyst component: weighing titanium dioxide loaded with active components of zirconium oxide and aluminum oxide, adding the prepared cocatalyst component solution according to the equal solid-to-liquid ratio of 1:5, soaking for 24h, and drying at 100 ℃ for 12h to obtain CrO2-K/TiO2/Al2O3A photocatalyst.
The obtained catalyst is subjected to catalytic evaluation in a gas-solid photocatalytic reaction device, the experiment is carried out in a low-temperature photocatalytic Claus reactor at the temperature of 80 ℃, and H with lower concentration is introduced2S、SO2Evaluation of Activity by simulating Claus acid gas, H2S concentration is 10000ppm, SO25000ppm, N2Is the balance gas. Carrying out photocatalysis and hydrolysis reaction on the Claus acid gas under the conditions of ultraviolet irradiation (the wavelength of the ultraviolet lamp is 365nm) and catalyst existence. Final hydrolytic activity 98%, Claus activity94% with a sulfur recovery of 99.6%.
The reaction apparatus of examples 3 to 4 is shown in fig. 1, and includes a combustion furnace 1, a waste heat boiler 2, a heater 4, a first-stage condenser 3, a first-stage claus reactor 5, a second-stage condenser 6, a second-stage claus reactor 7, a third-stage condenser 9, a third-stage claus reactor 10, a fourth-stage condenser 11, a tail gas incinerator 12, and a chimney 13, which are connected in sequence, wherein a light source 8 is provided in the second-stage claus reactor 7 and the third-stage claus reactor 10;
the first-stage Claus reactor 5, the second-stage Claus reactor 7 and the third-stage Claus reactor 10 realize catalyst regeneration and Claus reactions at different temperatures in turn through a program control valve 14;
example 3
Low-temperature photocatalytic claus sulfur recovery:
the method comprises the following steps: thermal reaction stage
Will contain H2Sour gas and O of S2Introducing into a combustion furnace, performing Claus combustion reaction at 1200 deg.C to obtain one third of H2S and O2Reaction to form SO2Then under high temperature conditions, H2S and SO2Generating a process gas containing elemental sulfur by a Claus reaction, cooling the generated process gas to 300 ℃ in a waste heat boiler, recovering certain heat energy, then entering a primary condenser, and separating liquid sulfur at 180 ℃;
step two: stage of catalytic reaction
(2.1) conventional Claus reaction: heating the process gas after the first-stage condenser separates the liquid sulfur to 260 ℃ by a heater, allowing the process gas to enter a first-stage Claus reactor for reaction to generate elemental sulfur, simultaneously regenerating a saturated catalyst adsorbing solid and/or liquid elemental sulfur in the previous operation period, allowing the process gas to enter a second-stage condenser for condensation to 130 ℃ after the reaction is finished, and separating the liquid sulfur;
(2.2) sub-dew point low temperature Claus reaction: the process gas generated by the secondary condenser in the step (2.1) enters a secondary Claus reactor, and under the condition that the light with the wavelength of an ultraviolet lamp of 185nm and a catalyst exist simultaneously, the process gas is subjected to photocatalytic Claus reaction (namely low-temperature sub-dew point Claus reaction) and hydrolysis reaction, the reaction temperature is 130 ℃, the residual organic sulfur is fully hydrolyzed into inorganic sulfur in the hydrolysis process, and the low-temperature Claus reaction is carried out, so that the Claus activity and the hydrolysis efficiency are improved, the operation cost is reduced, the liquid elemental sulfur generated after the reaction is gasified and desorbed in a catalyst regeneration mode, and enters a tertiary condenser with the residual gas to be condensed to 90 ℃, the liquid sulfur is separated, and the residual process gas is left;
(2.3) a sub-solid point low-temperature Claus reaction: the process gas generated by the third-level condenser enters a third-level Claus reactor, and under the condition that the light with the wavelength of an ultraviolet lamp of 185nm and a catalyst exist at the same time, the process gas is subjected to photocatalytic sub-solid point low-temperature Claus reaction at 70 ℃ to generate elemental sulfur, wherein the elemental sulfur comprises solid elemental sulfur, liquid elemental sulfur and gaseous elemental sulfur;
(2.4) product separation: and (3) gasifying and desorbing the solid elemental sulfur and the liquid elemental sulfur generated in the step (2.3) in a catalyst regeneration mode, introducing the gasified and desorbed elemental sulfur and the gaseous elemental sulfur into a four-stage condenser together, separating liquid sulfur at 70 ℃, and burning the separated tail gas in a burning furnace and then discharging the tail gas by a chimney finally reaching the standard.
In the above process, the catalyst regeneration is carried out by heating to 300-400 ℃ to gasify and remove the liquid or solid elemental sulfur adsorbed in the catalyst.
The catalyst in the first-stage Claus reactor adopts a commercial high-efficiency Claus reaction catalyst, such as LS-951 and CSR-2 alumina catalyst;
the catalyst used for the sub-dew point low temperature Claus reaction and the sub-solid point low temperature Claus reaction was gamma-Fe as obtained in example 12O3-K/TiO2The total recovery rate of the photocatalyst and the sulfur is more than 99.8 percent.
Example 4
Low-temperature photocatalytic claus sulfur recovery:
the method comprises the following steps: thermal reaction stage
Will contain H2Sour gas and O of S2Introducing into a combustion furnace, performing Claus combustion reaction at 1200 deg.C to obtain one third of H2S and O2Reaction to form SO2Then under high temperature conditions, H2S and SO2Generating a process gas containing elemental sulfur by a Claus reaction, cooling the generated process gas to 350 ℃ in a waste heat boiler, recovering certain heat energy, then entering a primary condenser, and separating liquid sulfur at 170 ℃;
step two: stage of catalytic reaction
(2.1) conventional Claus reaction: heating the process gas after the first-stage condenser separates the liquid sulfur to 240 ℃ by a heater, allowing the process gas to enter a first-stage Claus reactor for reaction to generate elemental sulfur, simultaneously regenerating a saturated catalyst adsorbing solid and/or liquid elemental sulfur in the previous operation period, allowing the process gas to enter a second-stage condenser for condensation to 110 ℃ after the reaction is finished, and separating the liquid sulfur;
(2.2) sub-dew point low temperature Claus reaction: the process gas generated by the secondary condenser in the step (2.1) enters a secondary Claus reactor, under the condition that the illumination with the wavelength of an ultraviolet lamp of 365nm and a catalyst exist at the same time, the process gas is subjected to photocatalytic Claus reaction (namely low-temperature sub-dew point Claus reaction) and hydrolysis reaction, the reaction temperature is 120 ℃, the residual organic sulfur is fully hydrolyzed into inorganic sulfur in the hydrolysis process to generate low-temperature Claus reaction, so that the Claus activity and the hydrolysis efficiency are improved, the operation cost is reduced, the liquid elemental sulfur generated after the reaction is gasified and desorbed in a catalyst regeneration mode, the liquid elemental sulfur and the residual gas enter a tertiary condenser to be condensed to 80 ℃, liquid sulfur is separated, and the residual process gas is left;
(2.3) a sub-solid point low-temperature Claus reaction: the process gas generated by the third-level condenser enters a third-level Claus reactor, and under the condition that the illumination with the wavelength of 365nm of an ultraviolet lamp and a catalyst exist at the same time, the photocatalytic sub-solid point low-temperature Claus reaction is carried out at the temperature of 90 ℃ to generate elemental sulfur, wherein the elemental sulfur comprises solid elemental sulfur, liquid elemental sulfur and gaseous elemental sulfur;
(2.4) product separation: and (3) gasifying and desorbing the solid elemental sulfur and the liquid elemental sulfur generated in the step (2.3) in a catalyst regeneration mode, introducing the gasified and desorbed elemental sulfur and the gaseous elemental sulfur into a four-stage condenser together, separating liquid sulfur at 50 ℃, and burning the separated tail gas in a burning furnace and then discharging the tail gas by a chimney finally reaching the standard.
In the above process, the catalyst regeneration is carried out by heating to 300-400 ℃ to gasify and remove the liquid or solid elemental sulfur adsorbed in the catalyst.
The catalyst in the first-stage Claus reactor adopts a commercial high-efficiency Claus reaction catalyst, such as LS-951 and CSR-2 alumina catalyst;
the catalysts used for the sub-dew point low temperature Claus reaction and the sub-solid point low temperature Claus reaction were CrO as obtained in example 22-K/TiO2/Al2O3The total recovery rate of the photocatalyst and the sulfur is more than 99.6 percent.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
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