Adsorbent for desulfurization, method for manufacturing the same, and method for desulfurizing natural gas using the same

Abstract

This invention provides a desulfurization adsorbent that exhibits excellent adsorption performance for both organic and inorganic sulfur compounds while ensuring an appropriate level of durability, a method for producing the same, and a method for desulfurizing natural gas using the same. [Solution] An adsorbent for desulfurization according to one embodiment comprises a support containing an inorganic binder doped with iron oxide and a zeolite; and a metal oxide supported on the support.

Description

[Technical Field]

[0001] This invention relates to a desulfurization adsorbent, a method for producing the same, and a method for desulfurizing natural gas using the same. [Background technology]

[0002] Natural gas supplied domestically as so-called "city gas" contains an odorant that includes sulfur (S). This is to allow for immediate detection through the sense of smell in the event of a natural gas leak.

[0003] As the sulfur (S)-containing odorant, tetrahydrothiophene (THT) and tert-butyl mercaptan (TBM) are used in a volume ratio of 7:3.

[0004] Therefore, in the industry that produces hydrogen from natural gas, a process to remove the sulfur (S)-containing odorant, i.e., a desulfurization process, is an essential step.

[0005] The adsorbent commonly used for desulfurization in this industry is a zeolite-based adsorbent.

[0006] However, while zeolite-based adsorbents have excellent adsorption performance for tetrahydrothiophene, which has a cyclic structure, their adsorption performance for tert-butyl mercaptan, which has a chain structure, is relatively low. As a result, when zeolite-based adsorbents reach the end of their lifespan, tert-butyl mercaptan often breakthroughs. Therefore, improving the adsorption performance of mercaptans could extend the lifespan of the adsorbent.

[0007] Furthermore, natural gas contains a variety of chain-like organic sulfur compounds in addition to tert-butyl mercaptan, and also contains hydrogen sulfide (H2S), a type of inorganic sulfur compound, at a certain level. Zeolite-based adsorbents lack sufficient adsorption capacity for these compounds as well. [Overview of the project] [Problems that the invention aims to solve]

[0008] One embodiment provides a desulfurization adsorbent that (1) exhibits excellent adsorption performance for both organic and inorganic sulfur compounds, while (2) ensuring an appropriate level of durability. [Means for solving the problem]

[0009] One embodiment provides a desulfurization adsorbent comprising an inorganic binder doped with iron oxide and a support comprising a zeolite; and a metal oxide supported on the support.

[0010] Another embodiment provides a method for producing the adsorbent.

[0011] Another embodiment provides a method for desulfurizing natural gas using the adsorbent. [Effects of the Invention]

[0012] The desulfurization adsorbent of one embodiment exhibits (1) excellent adsorption performance for both organic sulfur compounds and inorganic sulfur compounds, while (2) ensuring an appropriate level of durability.

[0013] Therefore, (1) by using the desulfurization adsorbent of one embodiment, a variety of sulfur compounds can be effectively removed, not limited to tetrahydrothiophene and tertiary butyl mercaptan. Furthermore, (2) the desulfurization adsorbent of one embodiment can maintain an appropriate level of durability during the supply, storage, and / or charging process of the product into the desulfurization reactor.

[0014] Furthermore, by using the desulfurization adsorbent of one embodiment, it is possible to reduce the sulfur content in natural gas to an ultra-low concentration of 10 ppb or less. [Modes for carrying out the invention]

[0015] (Definition of terms) Throughout this specification, when a part "includes" a component, it means that, unless otherwise specified, it may include other components rather than excluding them.

[0016] The terms "stage" or "stage" used throughout this specification do not mean "stage for".

[0017] Unless otherwise defined herein, particle size may refer to average particle size. Furthermore, particle size refers to the average particle size (D50), which means the diameter of the particle whose cumulative volume in the particle size distribution is 50% by volume. Average particle size (D50) can be measured by methods widely known to those skilled in the art, such as using a particle size analyzer, or by using a transmission electron microscope or scanning electron microscope. Alternatively, it can be measured using a dynamic light-scattering device, and the average particle size (D50) value can be calculated after data analysis and counting the number of particles in each particle size range. Alternatively, it can be measured using the laser diffraction method. More specifically, when measuring using the laser diffraction method, the particles to be measured are dispersed in a dispersion medium, then introduced into a commercially available laser diffraction particle size analyzer (for example, Microtrac's MT3000), and after irradiating with ultrasound at approximately 28 kHz at an output of 60 W, the average particle size (D50) based on the 50% particle size distribution in the analyzer can be calculated.

[0018] Based on the above definitions, embodiments of the present invention will be described in detail. However, these are presented as examples and do not limit the present invention, which is only defined by the scope of the claims described below.

[0019] (Adsorbent for desulfurization) One embodiment provides an adsorbent for desulfurization, comprising a support in which an inorganic binder doped with iron oxide and zeolite are aggregated; and a metal oxide supported on the support.

[0020] Generally in the industry, a method is used in which zeolite is filled as an adsorbent into an adsorption machine, and natural gas is passed through the adsorption machine filled with the zeolite to remove sulfur.

[0021] Here, zeolite as an adsorbent must be formed into a specific shape for use in order to suppress the differential pressure within the process and the generation of dust. Also, in order to complement the physical durability of zeolite, it must be appropriately mixed with an inorganic binder such as alumina or silica and formed.

[0022] However, generally known inorganic binders such as alumina and silica have excellent adhesive strength, durability, and heat resistance, but do not have adsorption performance for sulfur compounds.

[0023] Therefore, it can be seen that the adsorbents for desulfurization generally provided in the industry are inferior in adsorption performance for sulfur compounds only due to the content of the inorganic binder.

[0024] (1) Iron oxide In one embodiment, iron oxide that can function as an inorganic binder while being an adsorbent is introduced.

[0025] Specifically, as an inorganic binder, iron oxide can ensure durability at an appropriate level while reducing the content of the inorganic binder excluding iron oxide.

[0026] Furthermore, since the iron oxide exhibits excellent adsorption performance not only for organic sulfur compounds (e.g., tetrahydrothiophene, tert-butyl mercaptan, and other chain-like organic sulfur compounds) but also for inorganic sulfur compounds (e.g., hydrogen sulfide) as an adsorbent, it is possible to obtain effects that could not be expected from desulfurization adsorbents generally available in the industry.

[0027] Therefore, by introducing iron oxide according to one embodiment, it is possible to improve the adsorption performance to sulfur compounds while reducing the inorganic binder content excluding iron oxide.

[0028] (2) Inorganic binders doped with iron oxide However, when impregnating or mixing iron oxide with molded zeolite, there is a problem that the sulfur removal performance decreases as the iron oxide content increases, clogging the pores of the zeolite. Therefore, a suitable method for manufacturing an adsorbent is needed that can mix a sufficient amount of iron oxide without hindering the adsorption performance of the zeolite.

[0029] In one embodiment, prior to forming the zeolite, an inorganic binder is doped with iron oxide, and by forming the iron oxide-doped inorganic binder together with the zeolite, it is possible to improve the dispersion of iron oxide, maintain a low average particle size, and improve the sulfur adsorption performance of iron oxide while preventing the iron oxide from clogging the pores of the zeolite.

[0030] A method for producing an iron oxide-doped inorganic binder in one embodiment, and a method for molding it together with a zeolite, will be described later.

[0031] In short, the desulfurization adsorbent of one embodiment (1) exhibits excellent adsorption performance for both organic and inorganic sulfur compounds, while (2) ensuring an appropriate level of durability.

[0032] Therefore, (1) by using the desulfurization adsorbent of one embodiment, a variety of sulfur compounds can be effectively removed, not limited to tetrahydrothiophene and tert-butyl mercaptan. Furthermore, (2) the desulfurization adsorbent of one embodiment can maintain an appropriate level of durability during the supply, storage, and / or charging process of the product into the desulfurization reactor.

[0033] Furthermore, by using the desulfurization adsorbent according to one embodiment, it is possible to maintain the sulfur concentration in natural gas at 10 ppb or less.

[0034] The following describes in more detail one embodiment of a desulfurization adsorbent.

[0035] support In one embodiment of a desulfurization adsorbent, the support is an aggregate of an iron oxide-doped inorganic binder and a zeolite.

[0036] The iron oxide-doped inorganic binder provides sufficient physical strength to allow the zeolite molded product to be used in the process, and because the iron oxide is doped into the inorganic binder, it does not clog the pores of the zeolite.

[0037] The iron oxide-doped inorganic binder may contain the iron oxide and the inorganic binder in a weight ratio of 1:4 to 2:1, 1:3.5 to 1.8:1, or 1:3 to 1.5:1. If the iron oxide content is too high, the strength of the molded product may be weakened, causing it to easily break in the adsorbent and generate dust. On the other hand, if the iron oxide content is too low, the desired adsorption performance cannot be obtained.

[0038] The inorganic binder and zeolite doped with iron oxide within the support may be present in weight ratios of 1:1 to 1:5, 1:1.5 to 1:4.5, or 1:2 to 1:4. If the content of the inorganic binder itself or the inorganic binder doped with iron oxide is excessively high, there is a problem of reduced efficiency in removing sulfur components from the LNG. On the other hand, if the content is excessively low, there is a problem of weakened strength in the molded product.

[0039] When the above range is satisfied, the adsorption performance by the zeolite, the binding force of the inorganic binder, and the binding force and adsorption performance by iron oxide can be harmonized.

[0040] The binder is not particularly limited as long as it is an inorganic binder with binding properties, but may be alumina, boehmite, pseudo-boehmite, silica, titania, or a combination thereof. These may be porous.

[0041] The zeolite is not particularly limited as long as it has pores large enough for organic sulfur compounds to penetrate, but it may be zeolite Y, zeolite X, zeolite ZSM-5, zeolite Beta, zeolite ferrierite, zeolite SSZ-13, or a combination thereof. Of these, zeolite Y, which has a high aluminum (Al) content and a low silicon (Si) content, may allow for easier penetration of organic sulfur compounds.

[0042] The support may be a molded article containing an inorganic binder doped with iron oxide and the zeolite, and may be, for example, a pelletized product formed by extrusion. When molded in this manner, sufficient macropores are formed within the molded article, facilitating material transfer within the article and providing sufficient physical strength.

[0043] The support may be present in an amount of 90-99% by weight, 92-97% by weight, or 93-95% by weight relative to 100% by weight of the total amount of the desulfurization adsorbent; the metal oxide may be present in an amount of 1-10% by weight, 3-8% by weight, or 5-7% by weight.

[0044] Within this range, the effects of the support and the metal oxide can be harmonized.

[0045] metal oxides The aforementioned metal oxide is not particularly limited as long as it is a substance that adsorbs organic sulfur compounds, but may include copper oxide, alkali metal oxide, alkaline earth metal oxide, or a combination thereof.

[0046] The aforementioned metal oxides may include, for example, copper oxide, calcium oxide, and potassium oxide, and can be used in a variety of ratios without being limited to a specific ratio, but in this specification they were used in a 10:1:1 weight ratio.

[0047] Breaking strength of desulfurization adsorbents When measuring the compressive strength in the columnar direction of a cylindrical object using the MT-50 tablet hardness tester instrument, the compressive strength of the desulfurization adsorbent may be 10-100N, 20-80N, or 30-70N.

[0048] (Method for manufacturing desulfurization adsorbents) In another embodiment, a method for producing a desulfurization adsorbent is provided, comprising the steps of: producing a mixture of an aqueous solution of an iron precursor and an inorganic binder; producing an inorganic binder doped with an iron precursor from the mixture; mixing the inorganic binder doped with an iron precursor and a zeolite to produce a precursor for a support; calcining the precursor for the support to convert the iron precursor to iron oxide and obtain a support; and supporting a metal oxide on the support.

[0049] According to this, the desulfurization adsorbent of the aforementioned embodiment can finally be obtained.

[0050] The following explanation will omit any repetition of the above and will describe in detail the manufacturing method of a desulfurization adsorbent according to one embodiment.

[0051] Process for producing a mixture of an aqueous solution of an iron precursor and an inorganic binder. First, iron oxide itself is not used as a raw material. When iron oxide itself is used, the particle size of readily available iron oxide is excessively large, which can result in only a slight improvement in adsorption performance.

[0052] The aforementioned iron precursor is not particularly limited as long as it is a substance that can be converted to iron oxide in the calcination stage described later, but it may be iron nitrate, iron chloride, iron acetate, or a combination thereof.

[0053] The weight ratio of the iron precursor to the inorganic binder in the iron precursor aqueous solution may be 1:1 to 11:1, 1.5:1 to 10:1, or 1.8:1 to 8:1. When within this range, the final weight ratio of iron oxide to the inorganic binder in the desulfurization adsorbent can satisfy the range of 1:4 to 2:1, 1:3.5 to 1.8:1, or 1:3 to 1.5:1.

[0054] Manufacturing process for inorganic binders doped with iron precursors When producing an inorganic binder doped with an iron precursor from the aforementioned mixture, it is possible to produce it by simple mixing alone, but in some cases, acids, bases, etc., can be added.

[0055] Specifically, when producing an inorganic binder doped with the iron precursor, an acid or a base can be added to the mixture; or an acid and a base can be added sequentially; or a base and an acid can be added sequentially.

[0056] Depending on the type of inorganic binder, the necessity of acids and bases, their order of use, and their amounts can be changed.

[0057] The acid may be nitric acid, hydrochloric acid, acetic acid, formic acid, sulfuric acid, phosphoric acid, or a combination thereof, and the base may be ammonia, alkali metal hydroxide, alkaline earth metal hydroxide, or a combination thereof.

[0058] For example, when pseudoboehmite is used as the inorganic binder, acids and bases can be added sequentially.

[0059] Process for manufacturing a support precursor The aforementioned iron precursor can be mixed with a doped inorganic binder and zeolite, and after kneading this mixture, it can be extruded.

[0060] The extrusion molding may involve pelletizing the mixed mixture. This extrusion molding method can improve durability compared to zeolite that exists individually rather than as pellets, and may facilitate the production and supply of the product.

[0061] During the extrusion molding process, organic additives can be used to facilitate pelletization of the mixed mixture. For example, a variety of substances such as acrylates, cellulose, and polyvinyl alcohol can be used as organic additives. Since these organic additives can play a role in forming pores in the final support after firing, it is necessary to select an appropriate organic additive and its amount.

[0062] A process of converting a support precursor into a support. The precursor material of the support can be dried in an air atmosphere at 100 to 150°C. This completely removes moisture from the precursor material of the support, such as pelletized extruded products.

[0063] Subsequently, the firing can be carried out at 400-700°C. During this process, the precursor material of the support, such as the iron precursor in the pelletized extruded product, is oxidized, and the organic additives are decomposed (removed) to obtain the support. Therefore, if the firing temperature is excessively high, the adsorption performance may decrease due to sintering of the zeolite and iron oxide and a decrease in zeolite acid sites. On the other hand, if the firing temperature is low, the decomposition of organic matter and conversion of precursors may not occur, and the adsorption performance may not be exhibited.

[0064] Here, the support is an aggregate of an inorganic binder doped with iron oxide and a zeolite, and may be the same as the support in the aforementioned embodiment.

[0065] Process of supporting metal oxides on a support. To support the metal oxide on the support, the following steps can be taken: spraying an aqueous metal precursor solution onto the support; and drying and firing the support on which the aqueous metal solution has been sprayed. This is a method to enhance sulfur adsorption performance by supporting the metal oxide within the zeolite pores.

[0066] In the step of spraying the metal precursor aqueous solution onto the support, the metal precursor enters the pores of the inorganic binder and zeolite within the support. After drying in an air atmosphere at 100-150°C to remove moisture, the metal precursor is converted to a metal oxide by calcination at 300-500°C, ultimately yielding a desulfurization adsorbent.

[0067] If the firing temperature during the firing process becomes excessively high, the crystal size of the supported metal oxide may increase, leading to a decrease in adsorption performance. On the other hand, if the firing temperature becomes excessively low, the conversion of the precursor to oxide may not occur sufficiently, inhibiting the adsorbent function.

[0068] (Desulfurization method) Another embodiment provides a method for desulfurizing city gas using the adsorbent.

[0069] Since the adsorbent for desulfurization of this embodiment is used, it is not limited to tetrahydrothiophene and tertiary butyl mercaptan, and various sulfur compounds contained in city gas can be effectively removed.

[0070] Furthermore, by using the adsorbent for desulfurization of one embodiment, it is possible to produce high-purity hydrogen from natural gas.

[0071] For example, when using the adsorbent for desulfurization of one embodiment, the breakthrough adsorption amount of organic sulfur compounds (THT + TBM) is 20.0 to 100.0 mg S / g ads , 30.0 to 90.0 mg S / g ads , 40.0 to 70. mmg S / g ads , 50.0 to 60.0 mg S / g ads and may be, and the breakthrough adsorption amount of inorganic sulfur compound (H2S) is 10.0 to 50.0 mg S / g ads , 13.0 to 40 mg S / g ads , or 15.0 to 30.0 mg S / g ads and may be.

[0072] The breakthrough adsorption amount can be measured as follows.

[0073] Prepare a catalytic reactor with a peripheral temperature of 10 to 40 °C, 15 to 35 °C, or 20 to 30 °C and an internal pressure of 1 to 10 atm, 1 to 8 atm, 1 to 5 atm, or 1 to 2 atm to form a nitrogen atmosphere.

[0074] Natural gas containing a total of 0.1 to 500 ppm, or 0.1 to 100 ppm of organic sulfur compounds (for example, THT + TBM), inorganic sulfur compounds (for example, H2S), or a mixture is charged into the catalytic reactor at a gas hourly space velocity of 50 to 10,000 h -1 or less, 7,000 h -1 or less, or 1,000 h -1 or less.

[0075] A gas chromatograph (GC) equipped with a pulsed flame photometric detector (PFPD) is connected to the outlet of the reactor, and the amount of adsorbed organic sulfur compounds (THT+TBM) and inorganic sulfur compounds (H2S) is evaluated by measuring the amount adsorbed up to the point when the detected sulfur gas concentration breaks through at 10 ppb or higher.

[0076] The following description will refer to embodiments of the present invention, but these embodiments are for illustrative purposes only and do not limit the scope of the present invention to them alone. [Examples]

[0077] (Examples and Comparative Examples) Example 1 (1) Raw materials The raw materials used in Example 1 are as follows:

[0078] Zeolite: Zeolite Y with FAU crystal structure Inorganic binder: pseudo-boehmite Iron precursor: Iron nitrate notahydrate (Fe(NO3)3·9H2O) Metal precursor: A mixture of copper nitrate trihydrate, calcium nitrate tetrahydrate, and potassium nitrate in a weight ratio of 10:1:1. (2) Manufacturing of support In Example 1, iron nitrate notahydrate (Fe(NO3)3·9H2O) was used as the iron precursor.

[0079] The aforementioned iron precursor was dissolved in water to prepare an aqueous solution of the iron precursor. In this solution, the content of the iron precursor was 25% by weight out of a total amount of 100% by weight of the aqueous solution.

[0080] A mixture of the aforementioned iron precursor aqueous solution and the aforementioned pseudoboehmite was prepared. Here, the weight ratio of the iron precursor to the pseudoboehmite, excluding water, was set to 1.36:1. Through heat treatment, the iron precursor was converted to iron oxide and the pseudoboehmite to alumina, so that the weight ratio of iron oxide to alumina in the final adsorbent was 5:14.

[0081] Formic acid and aqueous ammonia were sequentially added to the aforementioned mixture to produce an inorganic binder doped with an iron precursor. Here, based on 100 parts by weight of water in the mixture, 0.8 parts by weight of formic acid and 0.4 parts by weight of aqueous ammonia were used to precipitate the iron precursor and obtain an inorganic binder doped with it.

[0082] The aforementioned iron precursor-doped inorganic binder, zeolite, and methylcellulose were added to a kneader in a weight ratio of 19:75:2.25 and kneaded together. The mixture was then extruded using a single-screw extruder to obtain the support precursor in pellet form (Φ1.5 mm).

[0083] The precursor material of the support was dried at 120°C for 12 hours to completely remove moisture, and then calcined in an air atmosphere at 550°C for 5 hours to convert the iron precursor in the precursor material of the support to iron oxide while completely decomposing (removing) the organic additives. The support obtained thereby is in the form of a pellet containing an inorganic binder doped with iron oxide and zeolite.

[0084] (3) Manufacturing of adsorbents A spray solution was prepared by dissolving metal precursors of copper oxide, calcium oxide, and potassium oxide (a mixture of copper nitrate trihydrate, calcium nitrate tetrahydrate, and potassium nitrate in a weight ratio of 10:1:1 based on oxides) in water.

[0085] The spray solution was sprayed onto the support to support the metal precursor. The spray solution was sprayed under conditions such that the content of copper oxide, calcium oxide, and potassium oxide in 100% by weight of the total amount of the final adsorbent was 5% by weight, 0.5% by weight, and 0.5% by weight, respectively.

[0086] The support on which the metal precursor was supported was dried at 120°C for 12 hours to completely remove moisture, and then calcined in an air atmosphere at 400°C for 3 hours to convert the metal precursor supported on the support into a metal oxide.

[0087] Example 2 The adsorbent of Example 2 was prepared in the same manner as in Example 1, except that the iron precursor was changed to iron chloride (FeCl3).

[0088] Example 3 The adsorbent of Example 3 was prepared in the same manner as in Example 1, except that the iron precursor was changed to iron acetate (Fe(C2H3O2)2).

[0089] Example 4 The adsorbent of Example 4 was prepared in the same manner as in Example 1, except that the amounts of iron precursor and pseudoboehmite used were changed so that the weight ratio of iron oxide to alumina in the final adsorbent was 10:9.

[0090] Example 5 The adsorbent of Example 5 was produced in the same manner as in Example 1, except that the amounts of iron precursor and pseudoboehmite used were changed so that the weight ratio of the iron oxide:alumina in the final adsorbent was 5:24, while the weight ratio of the iron precursor-doped inorganic binder, zeolite, and methylcellulose was changed to 29:65:2.25.

[0091] Example 6 The adsorbent of Example 6 was produced in the same manner as in Example 1, except that the amounts of iron precursor and pseudoboehmite used were changed so that the weight ratio of the iron oxide:alumina in the final adsorbent was 10:19, while the weight ratio of the iron precursor-doped inorganic binder, zeolite, and methylcellulose was changed to 29:65:2.25.

[0092] Example 7 The adsorbent of Example 7 was produced in the same manner as in Example 1, except that the amounts of iron precursor and pseudoboehmite used were changed so that the weight ratio of the iron oxide:alumina in the final adsorbent was 15:14, while the weight ratio of the iron precursor-doped inorganic binder, zeolite, and methylcellulose was changed to 29:65:2.25.

[0093] Comparative Example 1 The adsorbent of Comparative Example 1 was prepared in the same manner as in Example 1, except that 19 parts by weight of the inorganic binder itself, which was not doped with iron, was used.

[0094] Comparative Example 2 The adsorbent of Comparative Example 2 was manufactured in the same manner as in Example 1, except that an inorganic binder that was not doped with iron was used, but iron nitrate was mixed into the spray solution.

[0095] Comparative Example 3 The adsorbent of Comparative Example 3 was prepared in the same manner as in Example 1, except that iron oxide in powder form was used instead of an iron precursor.

[0096] Comparative Example 4 The adsorbent of Comparative Example 4 was prepared in the same manner as in Example 6, except that iron oxide in powder form was used instead of an iron precursor, and the weight ratio of iron oxide to inorganic binder was set to 10:19.

[0097] Comparative Example 5 (1) Manufacturing of support Iron nitrate was supported as an iron precursor on hydrogen foam Y zeolite with an SiO2 / Al2O3 ratio of 5.1. After drying at 120°C for 12 hours to completely remove moisture, the zeolite with supported iron oxide was produced by heat treatment at 550°C.

[0098] An inorganic binder, iron oxide-supported zeolite, and an organic additive were mixed in a ratio of 14:80:2.25, kneaded and extruded under the same conditions as in Example 1 to obtain a support in pellet form (Φ1.5 mm).

[0099] (2) Manufacturing of adsorbents The adsorbent of Comparative Example 5 was manufactured in the same manner as in Example 1, except that the aforementioned support was used.

[0100] Table 1 summarizes the types of iron precursors and the compositions of the final adsorbents for Examples 1-7 and Comparative Examples 1-5.

[0101] [Table 1] *In Examples 1-7, iron oxide is present in a form doped with an inorganic binder. *In Comparative Example 1, iron oxide is present in the inorganic binder itself, without doping. *In Comparative Example 2, iron oxide exists in a form supported on the molded article together with copper oxide, potassium oxide, and calcium oxide. *In Comparative Examples 3 and 4, iron oxide is present in a form attached to the support without being doped in the inorganic binder. *In Comparative Example 5, the iron oxide exists in a form supported on a zeolite that is not an inorganic binder.

[0102] (Example of evaluation) Evaluation Example 1: Adsorption Performance The adsorption performance of organic sulfur compounds (THT+TBM) and inorganic sulfur compounds (H2S) in Examples 1-7 and Comparative Examples 1-5 was evaluated as the breakthrough adsorption amount.

[0103] The reactor used was a quartz-based fixed-bed catalytic reactor with an inner diameter of 10 mm. The ambient temperature was maintained at 20 to 30 degrees Celsius, the gas composition inside the reactor was maintained as a nitrogen atmosphere, and the internal pressure was set to 1 atmosphere.

[0104] After charging the reactor with the adsorbent, nitrogen gas containing 35 ppm tetrahydrothiophene (THT) and 15 ppm tert-butyl mercaptan (TBM) is introduced at a gas hourly space velocity of 3,000 hF. -1 I played it.

[0105] A gas chromatograph (GC) equipped with a pulsed flame photometric detector (PFPD) was connected to the outlet of the reactor, and the amount of adsorbed organic sulfur compounds (THT+TBM) was evaluated by measuring the amount adsorbed up to the point where the sulfur concentration broke through at 10 ppb or higher.

[0106] Similarly, to evaluate the adsorption amount of inorganic sulfur compounds, nitrogen gas containing 28 ppm hydrogen sulfide (H2S) was subjected to a gas space velocity of 3,000 hV. -1 The amount of inorganic sulfur compounds adsorbed was evaluated by measuring the amount adsorbed up to the point when the sulfur concentration at the outlet detected by GC exceeded 10 ppb while the system was running.

[0107] Evaluation Example 2: Durability The durability of Examples 1-7 and Comparative Examples 1-5 was evaluated as compressive strength.

[0108] Specifically, the compressive strength in the direction of a cylindrical column was measured using the MT-50 tablet hardness tester.

[0109] The results from evaluation examples 1 and 2 are shown in Table 2 below.

[0110] [Table 2]

[0111] (1) According to Table 2 above, when the zeolite content is 75 parts by weight (iron oxide + inorganic binder 19 parts by weight) and the inorganic binder is excessively replaced with iron oxide (Example 4), it can be confirmed that the sulfur adsorption performance increases, but the problem of decreased fracture strength occurs, and the same result can be confirmed even when the content of (iron oxide + inorganic binder) in Examples 5, 6, and 7 is increased to 29 parts by weight. Therefore, it can be seen that the amount of iron oxide used as an inorganic binder substitute must be maintained at an appropriate level in order to use it in an adsorbent.

[0112] (2) Examples 1 to 3 showed an increase in organic sulfur and inorganic sulfur adsorption performance compared to Comparative Example 1, which confirms that replacing alumina, which has no sulfur adsorption performance, with iron oxide, which has organic sulfur and inorganic sulfur adsorption performance, is effective in improving the performance of the adsorbent.

[0113] (3) In Comparative Example 2, compared to Example 1, when iron precursors are impregnated and supported along with copper, potassium, and calcium precursors after extrusion molding of zeolite and alumina, a problem occurs in which pores become clogged due to an excessively large amount of metal supported compared to the zeolite content, and it can be confirmed that this reduces the adsorption performance. Similarly, in Comparative Example 5, even when iron oxide is supported on the zeolite and then extruded, the adsorption performance is low because the metal content supported on the zeolite is high.

[0114] (4) Comparative Examples 3 and 4 were manufactured by mixing iron oxide, which had been ground to a size of 5 micrometers, during extrusion molding. It was confirmed that the adsorption performance of iron oxide was relatively lower compared to the methods of Examples 1 and 6, in which iron oxide was dispersed and supported on alumina. This indicates that increasing the degree of dispersion of iron oxide is important for improving sulfur adsorption performance.

[0115] Although preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and can be implemented in various ways within the scope of the claims, the detailed description of the invention, and the attached drawings, and these also naturally fall within the scope of the present invention.

Claims

1. Supports composed of an inorganic binder and zeolite doped with iron oxide; and The support comprising a metal oxide, Adsorbent for desulfurization.

2. The inorganic binder doped with the aforementioned iron oxide is The iron oxide and the inorganic binder are contained in a weight ratio of 1:4 to 2:

1. The desulfurization adsorbent according to claim 1.

3. The inorganic binder and zeolite doped with iron oxide within the support are present in a weight ratio of 1:1 to 1:

5. The desulfurization adsorbent according to claim 1.

4. The inorganic binder is alumina, boehmite, pseudo-boehmite, silica, titania, or a combination thereof. The desulfurization adsorbent according to claim 1.

5. The zeolite in question is zeolite Y, zeolite X, zeolite ZSM-5, zeolite Beta, zeolite ferrielite, zeolite SSZ-13, or a combination thereof. The desulfurization adsorbent according to claim 1.

6. The support is a molded article containing an inorganic binder doped with iron oxide and the zeolite. The desulfurization adsorbent according to claim 1.

7. With respect to 100% by weight of the total amount of the desulfurization adsorbent, The aforementioned support contains 90 to 99% by weight; The aforementioned metal oxide is present in an amount of 1 to 10% by weight. Desulfurization adsorbent according to claim 1

8. The aforementioned metal oxide includes copper oxide, alkali metal oxide, alkaline earth metal oxide, or a combination thereof. The desulfurization adsorbent according to claim 1.

9. When measuring the compressive strength in the columnar direction of a cylindrical object using the MT-50 tablet hardness tester, The compressive strength of the aforementioned desulfurization adsorbent is 10 to 100 N. The desulfurization adsorbent according to claim 1.

10. The step of preparing a mixture of an aqueous solution of an iron precursor and an inorganic binder; A step of producing an inorganic binder doped with an iron precursor from the aforementioned mixture; The step of producing a support precursor by mixing the aforementioned iron precursor with an inorganic binder and zeolite; A step of calcining the precursor material of the support to convert the iron precursor to iron oxide and obtain the support; and The step of supporting a metal oxide on the support is included. A method for producing an adsorbent for desulfurization.

11. The aforementioned iron precursor is iron nitrate, iron chloride, iron chloride, or a combination thereof. A method for producing a desulfurization adsorbent according to claim 10.

12. The weight ratio of the iron precursor to the inorganic binder in the aforementioned aqueous solution of the iron precursor is 1:4 to 2:

1. A method for producing a desulfurization adsorbent according to claim 10.

13. During the production of an inorganic binder doped with the aforementioned iron precursor, Add an acid or a base to the aforementioned mixture; add an acid and a base sequentially; or add a base and an acid sequentially. A method for producing a desulfurization adsorbent according to claim 10.

14. The acid is nitric acid, hydrochloric acid, acetic acid, formic acid, sulfuric acid, phosphoric acid, or a combination thereof. A method for producing a desulfurization adsorbent according to claim 13.

15. The base is ammonia, alkali metal hydroxide, alkaline earth metal hydroxide, or a combination thereof. A method for producing a desulfurization adsorbent according to claim 13.

16. During the production of the precursor material for the support, The process includes the step of kneading a mixture of the iron precursor doped with an inorganic binder and a zeolite, and then extruding it. A method for producing a desulfurization adsorbent according to claim 10.

17. The process further includes drying the precursor material of the support in an air atmosphere at 100-150°C before firing, The aforementioned firing is carried out at 400-700°C. A method for producing a desulfurization adsorbent according to claim 10.

18. When supporting a metal on the aforementioned support, The step of spraying an aqueous metal precursor solution onto the support; and The process includes the steps of drying the support on which the aforementioned metal aqueous solution has been sprayed in an air atmosphere of 100 to 150°C and firing it at 300 to 500°C. A method for producing a desulfurization adsorbent according to claim 10.

19. Using an adsorbent according to any one of claims 1 to 9, A method for desulfurizing natural gas.

20. In a catalytic reactor with an ambient temperature of 10-40°C, an internal pressure of 1-10 atmospheres, and a nitrogen atmosphere, natural gas containing a total of 0.1-500 ppm of organic sulfur compounds, inorganic sulfur compounds, or mixtures thereof is introduced for 50-10,000 h. －１ The gas is charged at the gas hourly space velocity; When a gas chromatograph (GC) equipped with a pulsed flame photometric detector (PFPD) is connected to the outlet of the reactor, and the amount of adsorption up to the point when each gas breaks through at 10 ppb or more is detected, Breakthrough adsorption of organic sulfur compounds: 20.0–100.0 mg S / g ａｄ The breakthrough adsorption amount of inorganic sulfur compounds is 10.0 to 50.0 mg S / g. ａｄｓ That is, The method for desulfurizing natural gas according to claim 19.

Images