Iron oxyhydroxide desulfurizer, preparation method and application thereof

Abstract

The present invention provides an iron oxyhydroxide desulfurizer, a preparation method thereof and an application thereof in removing hydrogen sulfide. The iron oxyhydroxide desulfurizer composition comprises: ferrous sulfate; hydroxide A, the solubility of its corresponding sulfate A in water is greater than 40g / 100ml water; hydroxide B, which has a stronger alkalinity than hydroxide A, and the solubility of its corresponding sulfate B in water is less than 0.5g / 100ml water. In the present invention, the use of two hydroxides with different alkalinity can more flexibly control the reaction process with ferrous sulfate, which is convenient for production process control.

Description

Technical Field

[0001] The invention relates to the fields of chemical industry, energy, environmental protection, and in particular to an iron oxyhydroxide desulfurizer, a composition thereof, a preparation method thereof, and application in removing hydrogen sulfide. Background Art

[0002] Sulfur is widely present in nature, and in various forms. Hydrogen sulfide is a common toxic gas in the chemical industry. When people exploit or use fossil energy, sulfur will also be released in the form of hydrogen sulfide. For example, hydrogen sulfide will be present in the process of exploiting natural gas, shale gas, and associated gas from oil fields, or in the process of oil refining and coal-to-gas. On the one hand, hydrogen sulfide in industrial production will directly lead to poisoning and deactivation of catalysts in subsequent production stages. On the other hand, if hydrogen sulfide is directly discharged, it will seriously affect the environment and even cause poisoning of humans and animals. Therefore, it must be removed.

[0003] There are many types of desulfurizers in the prior art, among which iron oxyhydroxide is widely used as a desulfurizer in the chemical industry due to its good desulfurization performance. Iron oxyhydroxide desulfurizers are mostly used in fixed bed reactors and must be formed when used in fixed bed reactors. If the powder is directly loaded into the fixed bed reactor, it will cause excessive pressure drop and gas or liquid materials cannot pass through; even if the incoming gas pressure is large enough to force the material to pass through, it will also blow the powder desulfurizer in the fixed bed reactor away and bring it to the subsequent process, thereby clogging the pipeline, filter, or poisoning the subsequent catalyst, and damaging equipment such as the compressor.

[0004] In the process of realizing the present invention, the applicant found that in the non-powdered iron oxyhydroxide desulfurizer of the traditional technology, a binder needs to be added for molding or blocking the pores of the fixed bed reactor, and extrusion molding will further close the pores. If a calcium-based material is used, a large amount of calcium sulfate dihydrate will remain, and the content of active components is relatively low, which is bound to reduce the sulfur capacity. In addition, calcium sulfate dihydrate itself is relatively dense, which is bound to affect the penetration of hydrogen sulfide. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] In order to at least partially solve one of the above technical problems, the present invention provides an iron oxyhydroxide desulfurizer, a composition, a preparation method and an application thereof in removing hydrogen sulfide.

[0007] (II) Technical solution

[0008] In the first aspect of the present invention, a ferric oxyhydroxide desulfurizer composition is provided. The ferric oxyhydroxide desulfurizer composition comprises: ferrous sulfate; hydroxide A, the solubility of its corresponding sulfate A in water is greater than 40g / 100ml water; hydroxide B, which has stronger alkalinity than hydroxide A, and the solubility of its corresponding sulfate B in water is less than 0.5g / 100ml water.

[0009] In some embodiments of the present invention, the molar ratio of the sum of the hydroxide ions in hydroxide B and hydroxide A to the ferrous ions in ferrous sulfate is between 2.05:1 and 2.2:1.

[0010] In some embodiments of the present invention, ferrous sulfate is selected from one or more of the following materials: FeSO4·7H2O, FeSO4·6H2O, FeSO4·5H2O.

[0011] In some embodiments of the present invention, hydroxide A is selected from one or more of the following materials: lithium hydroxide, sodium hydroxide, potassium hydroxide, magnesium hydroxide, and the ratio of ferrous ions in ferrous sulfate to hydroxide ions in hydroxide A is between 1:1.6 and 1:1.9.

[0012] In some embodiments of the present invention, hydroxide B is selected from one or more of the following materials: calcium hydroxide, strontium hydroxide, barium hydroxide, and the ratio of ferrous ions in ferrous sulfate to hydroxide ions in hydroxide B is between 1:0.15 and 1:0.6.

[0013] In some embodiments of the present invention, ferrous sulfate is FeSO4·7H2O; hydroxide A is magnesium hydroxide; hydroxide B is calcium hydroxide; wherein the molar ratio of FeSO4·7H2O to magnesium hydroxide is between 1:0.8 and 1:0.9, and the molar ratio of FeSO4·7H2O to calcium hydroxide is between 1:0.15 and 1:0.25.

[0014] In the second aspect of the present invention, a method for preparing an oxyhydroxide iron desulfurizer is provided. The preparation method comprises: step A, kneading ferrous sulfate and hydroxide A; step B, adding hydroxide B and continuing kneading to obtain a semi-finished mud material; step C, molding the semi-finished mud material; step D, washing the molded material with water; step E, drying the washed material to obtain an oxyhydroxide iron desulfurizer; wherein the solubility of sulfate A corresponding to hydroxide A in water is greater than 40g / 100ml water; the alkalinity of hydroxide B is stronger than that of hydroxide A, and the solubility of its corresponding sulfate B in water is less than 0.5g / 100ml water.

[0015] In some embodiments of the present invention, the molar ratio of the sum of hydroxide ions in hydroxide B and hydroxide A to ferrous ions in ferrous sulfate is between 2.05:1 and 2.2:1.

[0016] In some embodiments of the present invention, the time interval between step B and step C after the kneading is completed is less than 0.5 h.

[0017] In some embodiments of the present invention, ferrous sulfate is selected from one or more of the following materials: FeSO4·7H2O, FeSO4·6H2O, FeSO4·5H2O.

[0018] In some embodiments of the present invention, hydroxide A is selected from one or more of the following materials: lithium hydroxide, sodium hydroxide, potassium hydroxide, magnesium hydroxide, and the ratio of ferrous ions in ferrous sulfate to hydroxide ions in hydroxide A is between 1:1.6 and 1:1.9.

[0019] In some embodiments of the present invention, hydroxide B is selected from one or more of the following materials: calcium hydroxide, strontium hydroxide, barium hydroxide, and the ratio of ferrous ions in ferrous sulfate to hydroxide ions in hydroxide B is between 1:0.15 and 1:0.6.

[0020] In some embodiments of the present invention, ferrous sulfate is FeSO4·7H2O; hydroxide A is magnesium hydroxide; hydroxide B is calcium hydroxide; wherein the molar ratio of FeSO4·7H2O to magnesium hydroxide is between 1:0.8 and 1:0.9, and the molar ratio of FeSO4·7H2O to calcium hydroxide is between 1:0.15 and 1:0.3.

[0021] In some embodiments of the present invention, step A includes: sub-step A1, solid-solid kneading ferrous sulfate and hydroxide A; sub-step A2, adding water to the solid-solid kneaded materials and continuing to knead.

[0022] In some embodiments of the present invention, step C includes: sub-step C1, shaping the semi-finished clay into a pancake or strip shape; sub-step C2, oxidizing the shaped material; sub-step C3, crushing the oxidized material to obtain a block or granular shaped object.

[0023] In some embodiments of the present invention, step E comprises: drying the washed material in a drying oven or naturally air-drying it until the water content is less than 20%.

[0024] In some embodiments of the present invention, sub-step A1 comprises: solid-solid mixing ferrous sulfate and hydroxide A for 20 to 60 minutes.

[0025] In some embodiments of the present invention, sub-step A2 includes: adding water to the solid-solid kneaded material and continuing to knead for 20 to 60 minutes.

[0026] In some embodiments of the present invention, sub-step C1 includes: shaping the semi-finished clay material into: a pancake shape with a thickness between 1 and 6 mm, or a long strip shape with a diameter between 1 and 6 mm.

[0027] In some embodiments of the present invention, sub-step C2 includes: placing the formed material in air for natural oxidation for 12 to 48 hours.

[0028] In some embodiments of the present invention, sub-step C3 includes: crushing the oxidized pancake-shaped material into blocks with a particle size between 1 and 6 mm, or crushing the oxidized long-hole material into particles with a particle size between 1 and 6 mm.

[0029] In some embodiments of the present invention, in step E, the drying temperature in the drying oven is between 30 and 80°C.

[0030] In the third aspect of the present invention, a ferric oxyhydroxide desulfurizer is provided, which is prepared by the above preparation method.

[0031] In a fourth aspect of the present invention, there is provided a use of the above iron oxyhydroxide desulfurizer or the iron oxyhydroxide desulfurizer in removing hydrogen sulfide.

[0032] (III) Beneficial effects

[0033] It can be seen from the above technical solution that the present invention has at least one of the following beneficial effects compared with the prior art:

[0034] (1) Using two hydroxides, the production process is more controllable and flexible

[0035] Compared with one hydroxide, using two hydroxides with different alkalinity can more flexibly control the reaction process with ferrous sulfate, which is convenient for production process control.

[0036] (2) The sulfates corresponding to the two hydroxides serve as the desulfurizer skeleton and form pores, complementing each other and promoting

[0037] The solubility of sulfate B corresponding to hydroxide B in water is less than 0.5g / 100ml water, while the solubility of sulfate A corresponding to hydroxide A in water is greater than 40g / 100ml water. Sulfate B is insoluble in water and precipitates during the water washing process, serving as the skeleton and carrier of the desulfurizer. Sulfate A is easily soluble in water and detaches during the water washing process, leaving pores in the desulfurizer, increasing the reaction area with hydrogen sulfide and improving the sulfur capacity of the desulfurizer.

[0038] (3) The two hydroxides are added separately to ensure that the weaker alkaline hydroxide added first reacts fully.

[0039] During the kneading process, the weaker alkaline hydroxide A is added first, and after it fully reacts with ferrous sulfate, the stronger alkaline hydroxide B is added. If they are added at the same time, ferrous sulfate will react with hydroxide B first, and then the residual ferrous sulfate concentration will decrease and the acidity will decrease, which will lead to incomplete reaction between hydroxide A and ferrous sulfate.

[0040] (4) The hydroxide A uses magnesium hydroxide, and the reaction is milder and more controllable

[0041] The hydroxide A is selected from one or more of the following materials: lithium hydroxide, sodium hydroxide, potassium hydroxide, and magnesium hydroxide, all of which can realize the present invention.

[0042] In particular, when the hydroxide A is magnesium hydroxide, the reaction is relatively mild and the heat release is relatively small. If sodium hydroxide or lithium hydroxide is used, the reaction is extremely violent and will directly lead to burning of the product.

[0043] (5) Hydroxide B uses calcium hydroxide, taking advantage of the fact that calcium sulfate is used as a skeleton and is relatively soft.

[0044] The hydroxide B is selected from one or more of the following materials: calcium hydroxide, strontium hydroxide, barium hydroxide, all of which can realize the present invention.

[0045] In particular, the hydroxide B is calcium hydroxide, and its corresponding sulfate is calcium sulfate. Compared with strontium sulfate or barium sulfate, calcium sulfate is softer and is conducive to extrusion molding. At the same time, it is relatively loose, which is conducive to the washing out of sulfate A in the water washing step.

[0046] (6) Molding before calcium sulfate solidifies to avoid affecting extrusion molding

[0047] Molding within 0.5 hours after the semi-finished mud is formed can avoid blocking the extruder or solidifying in the kneading machine due to solidification of calcium sulfate.

[0048] (7) The advantage of washing before molding is that sulfate A is removed to form pores, which increases the sulfur capacity

[0049] Different from the traditional technology of washing before molding, magnesium hydroxide is used as hydroxide A and calcium hydroxide as hydroxide B. During the preparation process, molding is performed first and then washing is performed, so that sulfate A can occupy a certain space in the molded product. In the subsequent washing process, sulfate B acts as a skeleton and sulfate A is dissolved from its original position. The space originally occupied by sulfate A is converted into pores, thereby increasing the reaction area with hydrogen sulfide and improving the sulfur capacity of the desulfurizer. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 The present invention is a flowchart of a method for preparing an iron oxyhydroxide desulfurizer according to an embodiment of the present invention.

[0051] Figure 2 for Figure 1 The process diagram of the preparation method of ferric hydroxide desulfurizer is shown. DETAILED DESCRIPTION

[0052] The present invention optimizes the raw materials and preparation process of the ferric oxyhydroxide desulfurizer, and is expected to provide an ferric oxyhydroxide desulfurizer, so as to improve the controllability and flexibility of the preparation process and improve the efficiency of removing hydrogen sulfide.

[0053] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific implementation methods and with reference to the accompanying drawings.

[0054] First, the present invention provides an iron oxyhydroxide desulfurization agent composition, which comprises:

[0055] Ferrous sulfate;

[0056] Hydroxide A, the solubility of its corresponding sulfate A in water is greater than 40g / 100ml water;

[0057] A hydroxide B, which is more alkaline than the hydroxide A, and the solubility of its corresponding sulfate B in water is less than 0.5 g / 100 ml of water;

[0058] The molar ratio of the sum of the hydroxide ions in the hydroxide B and the hydroxide A to the ferrous ions in the ferrous sulfate is between 2.05:1 and 2.2:1.

[0059] It can be seen that two kinds of hydroxides with different alkalinity are used in the present invention, which can more flexibly control the reaction process with ferrous sulfate, and facilitate production process control. Further, the solubility of sulfate B corresponding to hydroxide B in water is less than 0.5g / 100ml water, and the solubility of sulfate A corresponding to hydroxide A in water is greater than 40g / 100ml water, and sulfate B is insoluble in water, and it is precipitated during the washing process, as the skeleton and carrier of the desulfurizer, sulfate A is soluble in water, and it is separated from it during the washing process, leaving pores in the desulfurizer, increasing the reaction area with hydrogen sulfide, and improving the sulfur capacity of the desulfurizer.

[0060] In the present invention, ferrous sulfate is selected from one or more of the following materials: FeSO4·7H2O, FeSO4·6H2O, FeSO4·5H2O. Compared with other forms of FeSO4, the three forms of FeSO4 have better controllability in reaction.

[0061] In the present invention, the hydroxide A is selected from one or more of the following materials: lithium hydroxide, sodium hydroxide, potassium hydroxide, and magnesium hydroxide. The ratio of the ferrous ions in the ferrous sulfate to the hydroxide ions in the hydroxide A is between 1:1.6 and 1:1.9.

[0062] Preferably, hydroxide A is magnesium hydroxide, and the molar ratio of FeSO4·7H2O to magnesium hydroxide is between 1:0.8 and 1:0.9. The reaction of magnesium hydroxide is relatively mild, and the heat release is relatively small. If sodium hydroxide or lithium hydroxide is used, the reaction is extremely violent, which will directly lead to burning of the product.

[0063] In the present invention, the hydroxide B is selected from one or more of the following materials: calcium hydroxide, strontium hydroxide, barium hydroxide, and the ratio of the ferrous ions in the ferrous sulfate to the hydroxide ions in the hydroxide B is between 1:0.15 and 1:0.6.

[0064] Preferably, hydroxide B is calcium hydroxide; the molar ratio of FeSO4·7H2O to calcium hydroxide is between 1:0.15 and 1:0.25. Hydroxide B is calcium hydroxide, and its corresponding sulfate is calcium sulfate. Compared with strontium sulfate or barium sulfate, calcium sulfate is softer and is conducive to extrusion molding. At the same time, it is relatively loose, which is conducive to washing out sulfate A in the water washing step.

[0065] Secondly, the present invention provides a method for preparing an iron oxyhydroxide desulfurizing agent. Figure 1 The present invention is a flowchart of a method for preparing an iron oxyhydroxide desulfurizer according to an embodiment of the present invention. Figure 2 for Figure 1 The process diagram of the preparation method of ferric hydroxide desulfurizer is shown.

[0066] Please refer to Figure 1 and Figure 2 The preparation method of the iron oxyhydroxide desulfurizer in this embodiment includes:

[0067] Step A, mixing ferrous sulfate and hydroxide A;

[0068] Step B, adding hydroxide B and continuing to knead to obtain a semi-finished mud material;

[0069] Step C, shaping the semi-finished clay material;

[0070] Step D, washing the formed material with water;

[0071] Step E, drying the washed material to obtain a porous iron oxyhydroxide desulfurizer;

[0072] The solubility of sulfate A corresponding to the hydroxide A in water is greater than 40 g / 100 ml of water; the alkalinity of the hydroxide B is stronger than that of the hydroxide A, and the solubility of the corresponding sulfate B in water is less than 0.5 g / 100 ml of water; the molar ratio of the sum of the hydroxide ions in the hydroxide B and the hydroxide A to the ferrous ions in the ferrous sulfate is between 2.05:1 and 2.2:1.

[0073] The following is a detailed description of each step in the method for preparing the iron oxyhydroxide desulfurizer of the present invention.

[0074] In this embodiment, ferrous sulfate is selected from one or more of the following materials: FeSO4·7H2O, FeSO4·6H2O, FeSO4·5H2O, preferably: FeSO4·7H2O.

[0075] In this embodiment, step A specifically includes: solid-solid kneading FeSO4·7H2O and hydroxide A for 20 to 60 minutes, then adding water and continuing to knead for 20 to 60 minutes.

[0076] The hydroxide A is lithium hydroxide, sodium hydroxide, potassium hydroxide, magnesium hydroxide, preferably magnesium hydroxide. Because other hydroxides release heat during the dissolution and reaction of water, the mixing process will cause a sharp rise in temperature, thereby causing over-temperature to burn the desulfurizer.

[0077] If hydroxide A is magnesium hydroxide, the molar ratio of FeSO4·7H2O to hydroxide A is 1:0.6 to 1:0.95, preferably 1:0.8 to 1:0.9. If hydroxide A is lithium hydroxide, sodium hydroxide, or potassium hydroxide, the molar ratio of FeSO4·7H2O to hydroxide A is 1:1.2 to 1:1.9, preferably 1:1.6 to 1:1.8. The purpose of making FeSO4·7H2O excessive is to allow hydroxide A to react completely, and secondly, the residual FeSO4·7H2O will form a binder in situ with hydroxide B later.

[0078] After solid-solid kneading, add an appropriate amount of water to allow FeSO4·7H2O to fully react with hydroxide A and consume all hydroxide A. This is because FeSO4·7H2O and hydroxide A may not react completely under water-poor conditions, especially magnesium hydroxide, which reacts slowly without adding water. The amount of water added is preferably 10% to 40% of the mass of alkali A, preferably 20% to 35%.

[0079] Taking magnesium hydroxide as an example, the reaction is as shown in formula ①.

[0080] FeSO4·7H2O+Mg(OH)2→MgSO4+Fe(OH)2+7H2O.............①

[0081] Taking sodium hydroxide as an example, the reaction is as shown in formula ②.

[0082] FeSO4·7H2O+2NaOH→Na2SO4+Fe(OH)2+7H2O.............②

[0083] In this embodiment, step B specifically includes: adding hydroxide B and mixing and grinding for 20 to 60 minutes to obtain a semi-finished mud material;

[0084] Hydroxide B is selected from one or more of the following materials: calcium hydroxide, strontium hydroxide, barium hydroxide, preferably calcium hydroxide. Calcium hydroxide is selected mainly because it can react with sulfate to form calcium sulfate that is slightly soluble in water. At this time, calcium sulfate can be stored in the desulfurizer as a skeleton structure and carrier. Although there are still other alkalis, such as strontium hydroxide or barium hydroxide, which can also react with sulfate to form a hardly soluble precipitate in water, the sulfate precipitate (strontium sulfate or barium sulfate) formed by them is not as soft as the formed calcium sulfate, and the extrusion molding process is difficult. At the same time, it is too dense, which hinders the dissolution of magnesium sulfate in the subsequent washing process.

[0085] Taking calcium hydroxide as an example, the mixing and grinding reaction generates calcium sulfate (CaSO4), which generates calcium sulfate dihydrate (CaSO4·2H2O) under water conditions, and the calcium sulfate dihydrate is retained in the desulfurizer as a binder. The molar ratio of FeSO4·7H2O to hydroxide B is 1:0.05-1:0.5, preferably 1:0.15-1:0.25. The ratio is the ratio of the residual ferrous sulfate heptahydrate that just reacts with hydroxide B after reaction ① or ②, or not too much, preferably a little too much. The reason for a little excess is that the reaction is in a water-poor mixing state, and there is a problem of uneven materials. A little excess can ensure that the ferrous sulfate heptahydrate reacts completely. The reaction is as shown in formula ③.

[0086] FeSO4·7H2O+Ca(OH)2→CaSO4·2H2O+Fe(OH)2+5H2O…………③

[0087] Regarding steps A and B, the following three points need to be explained:

[0088] (1) The two hydroxides are added separately to ensure that the weaker alkaline hydroxide added first reacts fully.

[0089] It should be noted that the ferrous sulfate reacts with the hydroxide A and the hydroxide B separately, so that the overall reaction time is short, the product will not solidify prematurely, and the quality of the obtained product is better.

[0090] In particular, when hydroxide A is magnesium hydroxide, the alkalinity of magnesium hydroxide is weak, and hydroxide B is strong in alkalinity, so the rate at which magnesium hydroxide reacts with ferrous sulfate is slow compared to hydroxide B. First, magnesium hydroxide is added, and ferrous sulfate is in an excessive state, which can ensure that the magnesium hydroxide reaction is fully reacted. At this time, a stronger hydroxide B with alkalinity is added to consume the remaining ferrous sulfate, and calcium sulfate precipitation is generated. After the calcium sulfate precipitation is generated, it is necessary to enter the subsequent steps in time, otherwise it will solidify. If magnesium hydroxide and hydroxide B are added at the same time, ferrous sulfate will preferentially react with hydroxide B, and the remaining ferrous sulfate will react with magnesium hydroxide after hydroxide B is consumed, but at this time, ferrous sulfate has been consumed by hydroxide B for a part, so that its concentration is reduced, and acidity decreases, which will inevitably lead to incomplete reaction of ferrous sulfate and magnesium hydroxide; in addition, because calcium sulfate has been generated in the material, it is easy to cause premature solidification, and block the extruder or solidify in the kneader.

[0091] (2) Using calcium hydroxide but reducing its content, utilizing its skeleton-forming function but avoiding its side effects

[0092] Compared with the technology of simply selecting calcium hydroxide and ferrous sulfate to react to produce ferric oxyhydroxide desulfurizer, in the present invention, most of the ferrous sulfate that reacts with magnesium hydroxide avoids the presence of a large amount of calcium sulfate dihydrate in the desulfurizer. On the one hand, the content of active components is increased and the sulfur capacity is increased; on the other hand, the dense calcium sulfate dihydrate is avoided from affecting the penetration of hydrogen sulfide.

[0093] Of course, if calcium hydroxide is not added, the desulfurizer lacks a skeleton and cannot be formed, which affects its application in fixed bed reactors. If other binders or additives are used, there are the following defects:

[0094] First, it increases costs;

[0095] Second, the addition of binder will block the pores to a certain extent. If extrusion molding is used, the high extrusion pressure will further block the pores.

[0096] Third, the peptizing agent used together with the binder or auxiliary agent is at least one of an organic acid and an inorganic acid. After the acid is added, a certain acid-base neutralization reaction will occur with the material during molding, generating new pores and playing a certain role in dispersing the binder, thereby reducing the effect of the binder blocking the pores. However, the introduction of the acid will inevitably corrode the ferric oxyhydroxide, thereby changing the alkalinity of the ferric oxyhydroxide, thereby affecting the desulfurization accuracy and sulfur capacity.

[0097] The preparation method of the present invention saves costs, facilitates molding, and does not produce side effects on ferric oxyhydroxide, thus achieving multiple goals at one stroke.

[0098] (3) Molding before calcium sulfate solidifies to avoid affecting extrusion molding

[0099] The time interval between step B and step C is less than 0.5 hours. Molding within 0.5 hours after the semi-finished mud material is formed can avoid the blockage of the extruder or solidification in the kneader due to the solidification of calcium sulfate.

[0100] In this embodiment, step C further includes:

[0101] Sub-step C1, spreading the semi-finished clay material into a thin pancake with a thickness of 1 to 6 mm, or extruding it into strips with a diameter of 1 to 6 mm, preferably extruding it into strips;

[0102] The semi-finished mud material is spread into a pancake or extruded into strips to disperse the mud material and also to shape it. The desulfurizer in the form of a pancake and then crushed into particles can also be directly used in a fixed bed reactor.

[0103] Sub-step C2, placing the obtained wafer or strip in air for natural oxidation for 12 to 48 hours;

[0104] The obtained wafer or strip is placed in the air for natural oxidation for 12 to 48 hours in order to oxidize the Fe(OH)2 generated in steps ①, ② and ③ to generate the desulfurization active component iron oxyhydroxide (FeOOH). The reaction is shown in formula ④.

[0105] 4Fe(OH)2+O2→4FeOOH+2H2O........................④

[0106] As the natural oxidation process progresses, it gradually dries up, and the reaction ends. Taking magnesium hydroxide as an example, the total reaction equation ⑤ is obtained by adding the reaction equations ① and ④, and the total reaction equation ⑥ is obtained by adding the reaction equations ③ and ④.

[0107] 4FeSO4·7H2O+4Mg(OH)2+O2→4FeOOH+4MgSO4·7H2O+2H2O.............⑤

[0108] 4FeSO4·7H2O+4Ca(OH)2+O2→4FeOOH+4CaSO4·2H2O+22H2O.............⑥

[0109] Sub-step C3, breaking the naturally oxidized wafers into small pieces of 1 to 6 mm, or breaking the strips into pieces of 1 to 6 mm in length;

[0110] The dried wafers or strips are broken up to facilitate subsequent washing. At the same time, particles that are too long or too large are not conducive to the filling of the fixed bed reactor and will affect the penetration of hydrogen sulfide into the particles.

[0111] In this embodiment, step D specifically includes: washing the crushed material with water, as shown in equations ⑤⑥.

[0112] After the reaction is completed, the material contains FeOOH (active component), MgSO4·7H2O, and CaSO4·2H2O; MgSO4·7H2O is a water-soluble salt, and CaSO4·2H2O is almost insoluble in water. MgSO4·7H2O is removed by water washing, while FeOOH and CaSO4·2H2O remain in the desulfurizer. After water washing, holes will be formed in the space originally occupied by MgSO4·7H2O.

[0113] Regarding step C and step D, it should be particularly noted that, unlike the traditional technology of first washing with water and then forming, the present invention is formed first and then washed with water. After forming, the generated soluble salt is used to occupy a certain space, which is subsequently removed by washing with water. The position originally occupied by the soluble salt becomes a pore, thereby increasing the porosity and the sulfur capacity.

[0114] In this embodiment, step E specifically includes: placing the washed material in a drying oven and drying it at 10-100°C or air drying it naturally until the moisture content is less than 20% to obtain an in-situ porous iron hydroxide oxide desulfurizer, and the drying temperature is preferably 30-80°C. The washed material is dried to obtain an in-situ porous iron hydroxide oxide desulfurizer. The drying temperature cannot exceed 100°C, preferably 30-80°C. If the temperature is too high, FeOOH will be dehydrated and inactivated, and if it is too low, the oxidation rate will be too slow, affecting production efficiency.

[0115] The present invention is described in detail below with reference to specific embodiments.

[0116] Table 1 Composition, ratio and test results of each component of the crossover experiment of the iron oxyhydroxide desulfurizer of the present invention

[0117]

[0118] Embodiment 1

[0119] Referring to Table 1, 10 mol of FeSO4·7H2O and 8.5 mol of magnesium hydroxide were kneaded in a kneader for 20 min, and then 200 g of water was added and kneaded for another 40 min.

[0120] Add 2 mol of calcium hydroxide into the kneader and continue kneading for 20 minutes to obtain a semi-finished mud material;

[0121] The semi-finished clay material is extruded into strips, and after drying for 2 days, the strips are broken into 3-6 mm long to obtain columnar particles;

[0122] Washing the columnar particles with water;

[0123] The washed material was dried at 70°C until the water content was less than 20%, thereby obtaining a porous iron oxyhydroxide desulfurizer having a sulfur capacity of 52% and a crushing resistance of 75 N / cm.

[0124] Embodiment 2

[0125] Similar to Example 1, the amount of magnesium hydroxide added is 8 mol; calcium hydroxide is replaced with strontium hydroxide, and the amount of strontium hydroxide added is 3 mol; the semi-finished mud material is not squeezed into strips, but spread into a pancake shape;

[0126] The obtained porous iron oxyhydroxide desulfurizer has a sulfur capacity of 43% and a crushing resistance of 65 N / cm.

[0127] Embodiment 3

[0128] Similar to Example 1, the amount of magnesium hydroxide added was 9.5 mol; calcium hydroxide was replaced with barium hydroxide, and the amount of barium hydroxide added was 0.75 mol; the semi-finished clay material was not squeezed into strips, but spread into a pancake shape;

[0129] The obtained porous iron oxyhydroxide desulfurizer has a sulfur capacity of 41% and a crushing resistance of 34 N / cm.

[0130] Embodiment 4

[0131] Similar to Example 1, magnesium hydroxide was replaced with lithium hydroxide, kneaded for 20 minutes, and then 400 g of water was added;

[0132] The obtained porous iron oxyhydroxide desulfurizer has a sulfur capacity of 46% and a crushing resistance of 72 N / cm.

[0133] Embodiment 5

[0134] Similar to Example 1, magnesium hydroxide was replaced with sodium hydroxide, kneaded for 20 minutes, and then 400 g of water was added;

[0135] The obtained porous iron oxyhydroxide desulfurizer has a sulfur capacity of 42% and a crushing resistance of 70 N / cm.

[0136] Embodiment 6

[0137] Similar to Example 1, magnesium hydroxide was replaced with potassium hydroxide, kneaded for 20 minutes, and then 400 g of water was added;

[0138] The obtained porous iron oxyhydroxide desulfurizer has a sulfur capacity of 38% and a crushing resistance of 71 N / cm.

[0139] In the above embodiments, the sulfur capacity test method is "HG / T 5759-2020 Room-temperature iron oxide desulfurizer", and the crushing resistance test method is "HG / T 2782-2011 Determination of crushing resistance of fertilizer catalyst particles".

[0140] Again, the present invention also provides an iron oxyhydroxide desulfurizer, which is prepared by the above preparation method.

[0141] Finally, the present invention also provides an application of the above iron oxyhydroxide desulfurizer composition or the iron oxyhydroxide desulfurizer in removing hydrogen sulfide.

[0142] So far, the various embodiments of the present invention have been introduced. According to the above description, those skilled in the art should have a clear understanding of the present invention.

[0143] The ordinal numbers used in the specification and claims, such as Arabic numerals, letters, etc., to modify the corresponding elements (or steps), are intended only to make a component (or step) with a certain name clearly distinguishable from another component (or step) with the same name, and do not mean that the component (or step) has any ordinal number, nor do they represent the order of one component (or step) and another component (or step). At the same time, unless the steps are specifically described or must occur in sequence, the order of the above steps is not limited to the above list, and can be changed or rearranged according to the required design.

[0144] Unless explicitly indicated to the contrary, the numerical parameters in the description and claims of the present invention may be approximate values ​​and can be changed according to the content of the present invention. Specifically, all the numbers recorded in the description and claims indicating the content of the composition, reaction conditions, etc., should be understood to be modified by the term "about" in all cases, and the meaning of the expression is to include a change of ±10% in some embodiments from a specific number.

[0145] Those skilled in the art should understand that in the claims and description of the present invention, the word "comprising" does not exclude the existence of elements (or steps) not listed in the claims. The word "a" or "an" preceding an element (or step) does not exclude the existence of multiple such elements (or steps).

[0146] For certain implementations, if they are not the key content of the present invention and are well known to ordinary technicians in the relevant technical field, they are not described in detail in the drawings or text of the specification due to space limitations. At this time, they can be understood by referring to the relevant prior art. In addition, the purpose of providing the above embodiments is only to make the present invention meet legal requirements, and the present invention can be implemented in many different forms and should not be interpreted as limited to the embodiments described herein. In addition, the above definitions of each element and method are not limited to the various specific structures, shapes or methods mentioned in the embodiments, and ordinary technicians in this field can simply change or replace them.

[0147] Similarly, it should be understood that in order to simplify the present invention, in the above description of the exemplary embodiments of the present invention, the various features of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. However, the method of the invention should not be interpreted as reflecting the following intention: the claimed invention requires more features than the features explicitly stated in each claim. More specifically, as reflected in the claims, each inventive aspect is less than all the features of the previous single embodiment. Moreover, the embodiments can be mixed and matched with each other or with other embodiments based on design and reliability considerations, that is, the technical features in different embodiments can be freely combined to form more embodiments. Therefore, the claims following the specific embodiment are hereby explicitly incorporated into the specific embodiment, wherein each claim itself serves as a separate embodiment of the present invention.

[0148] The above specific embodiments provide a detailed description of the objectives, technical means and beneficial effects of the present invention. It should be understood that the purpose of the detailed description is to enable those skilled in the art to understand the present invention more clearly, and it is not used to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing an iron oxyhydroxide desulfurizer, characterized in that: include: Step A, kneading ferrous sulfate and hydroxide A, wherein the hydroxide A is magnesium hydroxide; the ratio of ferrous ions in the ferrous sulfate to hydroxide ions in the hydroxide A is between 1:1.6 and 1:1.9; Step B, adding hydroxide B and continuing to knead to obtain a semi-finished mud material; Step C, shaping the semi-finished clay material, wherein the shaped material is in block or granular form; The step C comprises: sub-step C1, forming the semi-finished clay material into a pancake or strip shape; sub-step C2, oxidizing the formed material; sub-step C3, crushing the oxidized material to obtain a block or granular formed object; Step D, washing the formed material with water; Step E, drying the washed material to obtain an iron oxyhydroxide desulfurizer; The step E comprises: drying the washed material in a drying oven or naturally air-drying it until the moisture content is less than 20%, wherein when drying in a drying oven, the drying temperature is between 30 and 80°C; Among them, the solubility of sulfate A corresponding to the hydroxide A in water is greater than 40g / 100ml water; the alkalinity of the hydroxide B is stronger than that of the hydroxide A, and the solubility of its corresponding sulfate B in water is less than 0.5g / 100ml water.

2. The preparation method according to claim 1, characterized in that: The time interval between step B and step C after the kneading is completed is less than 0.5h; and / or The ferrous sulfate is selected from one or more of the following materials: FeSO4·7H2O, FeSO4·6H2O, FeSO4·5H2O; and / or The molar ratio of the sum of the hydroxide ions in the hydroxide B and the hydroxide A to the ferrous ions in the ferrous sulfate is between 2.05:1 and 2.2:1; and / or The hydroxide B is selected from one or more of the following materials: calcium hydroxide, strontium hydroxide, and barium hydroxide. The ratio of ferrous ions in the ferrous sulfate to hydroxide ions in the hydroxide B is between 1:0.15 and 1:0.

6.

3. The preparation method according to claim 1, characterized in that: The ferrous sulfate is: FeSO4·7H2O; The hydroxide B is: calcium hydroxide; The molar ratio of FeSO4·7H2O to magnesium hydroxide is between 1:0.8 and 1:0.9, and the molar ratio of FeSO4·7H2O to calcium hydroxide is between 1:0.15 and 1:0.

3.

4. The preparation method according to claim 1, characterized in that: The step A comprises: sub-step A1, solid-solid mixing and kneading ferrous sulfate and hydroxide A; sub-step A2, adding water to the solid-solid mixed materials and continuing to mix and knead.

5. The preparation method according to claim 4, characterized in that: The sub-step A1 comprises: solid-solid mixing of ferrous sulfate and hydroxide A for 20 to 60 minutes; and / or The sub-step A2 comprises: adding water to the solid-solid kneaded material and continuing to knead for 20 to 60 minutes; and / or The sub-step C1 comprises: shaping the semi-finished clay material into: a pancake with a thickness between 1 and 6 mm, or a strip with a diameter between 1 and 6 mm; and / or The sub-step C2 comprises: placing the formed material in the air for natural oxidation for 12 to 48 hours; and / or The sub-step C3 includes: crushing the oxidized pancake-shaped material into blocks with a particle size between 1 and 6 mm, or crushing the oxidized long-hole material into particles with a particle size between 1 and 6 mm.

6. A ferric oxyhydroxide desulfurizing agent, characterized in that: The method is prepared according to any one of claims 1 to 5.

7. Use of the iron oxyhydroxide desulfurizer as claimed in claim 6 in removing hydrogen sulfide.

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