A method for desulfurization of alkanes

Abstract

The application discloses a desulfurization method of alkane, which comprises the following steps: contacting alkane raw material stream with a primary sulfur adsorbent to perform primary desulfurization; contacting the stream after primary desulfurization with a sulfur conversion agent and a secondary sulfur adsorbent alternately at least once in the presence of hydrogen to perform secondary desulfurization; the primary sulfur adsorbent is a bimetallic adsorbent, and the primary sulfur adsorbent contains a first metal component and a second metal component; the sulfur conversion agent is an organic sulfur conversion inorganic sulfur catalyst containing a Group VIII metal and potassium; and the secondary sulfur adsorbent is an adsorbent containing alkali metal and / or alkaline earth metal metal oxide. The application removes most of the inorganic sulfur in hydrocarbon oil through a primary adsorption desulfurization mode, and then sequentially contacts with a sulfur conversion agent and a sulfur adsorbent, and sequentially performs organic sulfur conversion into inorganic sulfur and inorganic sulfur adsorption in the same reaction atmosphere, so that the ultra-deep desulfurization of sulfur in hydrocarbon oil is realized, and the sulfur content in hydrocarbon oil with relatively high sulfur content can be reduced to below 0.1 ppm or even lower.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of hydrocarbon desulfurization, and particularly relates to a desulfurization method of alkanes. BACKGROUND

[0002] Light hydrocarbon oil mainly includes C4-C8 alkanes, overhead oil, light naphtha, reforming raffinate oil and the like from oil refineries, and their efficient utilization has been the focus of the oil refining field. With the improvement of clean fuel standards, more refined technology and higher quality of products, the demand for ultra-low sulfur technology is increasing, and therefore the development of new ultra-deep desulfurization technology for ultra-low sulfur or nearly sulfur-free standards has become a research field of concern at home and abroad. For example, the C5C6 alkane isomerization technology to meet the upgrading of gasoline product quality, and the C6C7 alkane aromatization technology to increase the production of high-value-added aromatic hydrocarbons and hydrogen, all have extremely stringent requirements for the sulfur content of the raw material. In the existing C5, C6 alkane aromatization technology, there are low-temperature isomerization, medium-temperature isomerization and superacid isomerization, and the three catalysts have different requirements for the impurities of the raw material. Among them, the low-temperature aromatization catalyst has the lowest reaction temperature and the highest catalyst activity, but it has the most stringent requirements for the content of impurities such as sulfur and water in the raw material, and the content of the impurities is required to be less than 0.1 ppm. The C6C7 alkane aromatization technology is to convert C6-C8 alkanes into benzene, toluene, xylene and other light aromatic hydrocarbons under the action of Pt / KL molecular sieve catalyst and hydrogen, and to produce hydrogen. However, the Pt / KL molecular sieve catalyst is particularly sensitive to sulfur impurities in the reaction raw material, and a small amount of sulfur impurities will cause catalyst poisoning and deactivation, so the sulfur content of the raw material must be strictly controlled below 0.1 ppm.

[0003] Light hydrocarbon oil usually contains H2S, mercaptans, sulfides, carbon disulfide and other sulfides. At present, there are many methods for desulfurization of light hydrocarbon oil at home and abroad, such as alkali refining method, adsorption method, hydrofining, catalytic desulfurization and the like. In the existing technology, the removal technology of hydrogen sulfide in oil products is relatively mature. The most traditional method is alkali refining method, that is, the light hydrocarbon oil is mixed with alkali solution in a proper way, and then separated by sedimentation. This method can effectively remove acidic substances such as hydrogen sulfide in oil, but a large amount of alkali is used, and there is a problem of alkali emission. The most commonly used method is to use a solid desulfurizer to adsorb and remove hydrogen sulfide and other inorganic sulfides in oil products, but the removal efficiency of organic sulfides is not high. The main desulfurizers include iron-based desulfurizers, copper-based desulfurizers, zinc-based desulfurizers and the like. CN02112508.2 provides a reforming raw oil fine desulfurizer, which uses nickel as the main active component, zinc oxide as the auxiliary agent, and alumina as the carrier, so that the sulfur content in the reforming raw oil can be reduced to below 0.5 ppm. CN200780040837.7 provides a nickel-phosphide composite Ni xP's high capacity adsorbent removes sulfur from hydrocarbon streams, and can reduce sulfur content to about 1 ppm and lower under non-hydrogen conditions. Nickel-molybdenum-platinum type desulfurizers and nickel-platinum type desulfurizers developed in US4336130 and US4419224 can reduce sulfur content of reforming gasoline to below 0.5 ppm. Removal of organic sulfur is usually carried out by hydrodesulfurization, and conventional hydrodesulfurization catalysts such as Ni-Mo / Al2O3 and Co-Mo / Al2O3 catalysts convert organic sulfides in the feedstock into hydrogen sulfide by hydrogenation, and the hydrogenated product is cooled into a liquid and then passed through a stripping device to remove the generated hydrogen sulfide, and a large amount of hydrogen sulfide in the recycle gas needs to be removed by an adsorbent, and hydrogen sulfide in the product can further react with olefins to form mercaptans, so the sulfur content in the product after hydrogenation can be reduced to 0.5 ppm, but it is difficult to reduce it to below 0.1 ppm. A method for removing sulfur from a hydrodesulfurized naphtha feedstock disclosed in US5322615 includes first contacting the hydrodesulfurized naphtha feedstock with a adsorbent containing NiO, and then converting organic sulfur into hydrogen sulfide in the presence of a catalyst containing Group VIII metal, and then passing through a solid sulfur adsorbent containing an alkali metal or an alkaline earth metal to reduce the sulfur content to below 10 ppb, but the feedstock used in this method is a hydrodesulfurized naphtha after pre-hydrogenation treatment and fractionation, and the initial sulfur content of the feedstock is relatively low, generally below 2 ppm.

[0004] In summary, the existing single desulfurization process cannot simultaneously remove inorganic sulfides and organic sulfides, and it is also difficult to meet the requirement of deep desulfurization of the feedstock to ultra-low sulfur or even no sulfur; and the staged desulfurization process can only treat feedstocks with relatively low sulfur content, and it is difficult to meet the requirement of deep desulfurization of the feedstock with relatively high sulfur content to ultra-low sulfur or even no sulfur. How to deeply remove inorganic sulfides and organic sulfides in the feedstock with relatively high sulfur content is a technical problem to be solved at present. SUMMARY

[0005] The present application provides a desulfurization method of alkanes, which deeply removes inorganic sulfides and organic sulfides in a light hydrocarbon oil feedstock with relatively high sulfur content by a staged adsorption-catalysis-adsorption method.

[0006] The present application provides a desulfurization method of alkanes, which includes: contacting an alkanes feedstock stream with a primary sulfur adsorbent to perform primary desulfurization, to obtain a primary desulfurized stream; and alternately contacting the primary desulfurized stream with a sulfur conversion catalyst and a secondary sulfur adsorbent at least once in the presence of hydrogen to perform secondary desulfurization; the primary sulfur adsorbent is a bimetallic adsorbent, the primary sulfur adsorbent contains a first metal component and a second metal component, the first metal component is selected from nickel or copper, and the second metal component is selected from manganese or titanium; the sulfur conversion catalyst is an organic sulfur conversion inorganic sulfur catalyst containing Group VIII metal and potassium; and the secondary sulfur adsorbent is an adsorbent containing alkali metal and / or alkaline earth metal metal oxide.

[0007] Optionally, the primary desulfurization is performed in a primary desulfurization reactor, and the secondary desulfurization is performed in a secondary desulfurization reactor; the secondary desulfurization reactor is provided with multiple groups of interval-packed sulfur conversion agent layers and secondary sulfur adsorbent layers, and the inlet of the secondary desulfurization reactor is close to the sulfur conversion agent layers.

[0008] Optionally, the primary desulfurization reactor and the secondary desulfurization reactor are multiple, respectively; the outlet of any one of the primary desulfurization reactors is in fluid communication with the inlet of any one of the secondary desulfurization reactors.

[0009] Optionally, the conditions of the primary desulfurization include: temperature 100-250℃, pressure 0.1-3.0MPa, volume space velocity of the feed 0.5-20h-1, and hydrogen / oil volume ratio 0-100; the conditions of the secondary desulfurization include: temperature 250-400℃, pressure 0.1-2MPa, volume space velocity of the feed 0.5-10h-1, and hydrogen / oil volume ratio 200-2000; preferably, the conditions of the primary desulfurization include: temperature 150-200℃, pressure 0.3-1.0MPa, volume space velocity of the feed 2-10h-1, and hydrogen / oil volume ratio 0-50; the conditions of the secondary desulfurization include: temperature 280-350℃, pressure 0.3-1.0MPa, volume space velocity of the feed 1.0-8.0h-1, and hydrogen / oil volume ratio 200-1000. -1 -1 -1 -1

[0010] Optionally, when the hydrogen / oil volume ratio is 10-100 during the primary desulfurization, the primary sulfur adsorbent includes a carrier and two kinds of metal oxides supported on the carrier; the carrier is Al2O3 and SiO2, the first kind of metal oxide is NiO or CuO, and the second kind of metal oxide is MnO2 or TiO2; the mass percentage of the first kind of metal oxide is 20-50%, the mass percentage of the second kind of metal oxide is 5-15%, the mass percentage of SiO2 is 5-20%, and the mass percentage of Al2O3 is 15-70%, based on the mass of the primary sulfur adsorbent; preferably, the mass percentage of the first kind of metal oxide is 30-40%, the mass percentage of the second kind of metal oxide is 5-10%, the mass percentage of SiO2 is 10-15%, and the mass percentage of Al2O3 is 35-55%, based on the mass of the primary sulfur adsorbent.

[0011] ​​​​Optionally, when the volume ratio of hydrogen to oil is 0 during the first stage desulfurization, the first stage sulfur adsorbent comprises a carrier and the first metal component in elemental form and the second metal component in oxide form supported on the carrier, the carrier is Al2O3 and SiO2, the first metal component is Ni or Cu, and the second metal component is MnO2 or TiO2; the mass percentage of the first metal component is 15-35%, the mass percentage of the second metal component is 5-15%, the mass percentage of SiO2 is 5-20%, and the mass percentage of Al2O3 is 30-75%.

[0012] Optionally, the sulfur conversion agent comprises a carrier alumina and a Group VIII metal and metal K supported on the carrier alumina, the Group VIII metal is Pt and / or Pd; the mass percentage of the Group VIII metal is 0.2-2% and the mass percentage of metal K is 0.01-0.5%, based on the mass of the carrier alumina.

[0013] Optionally, the second stage sulfur adsorbent comprises an inorganic oxide carrier and a metal oxide supported on the inorganic oxide carrier, the inorganic oxide carrier is Al2O3 and / or SiO2, and the metal oxide is an oxide of an alkali metal and / or an alkaline earth metal; the alkali metal is Na or K, and the alkaline earth metal is Ca or Mg; the mass percentage of the metal in the metal oxide is 10-20%, based on the mass of the inorganic oxide carrier.

[0014] Optionally, the second stage sulfur adsorbent is K2O / Al2O3-SiO2 or CaO / Al2O3-SiO2.

[0015] Optionally, the alkane feed stream contains C4-C8 alkanes, and the sulfur content in the alkane feed stream is less than or equal to 50 ppm, based on the mass of the alkane feed stream; preferably, the sulfur content in the alkane feed stream is 0.2-50 ppm, based on the mass of the alkane feed stream; preferably, the sulfur content in the alkane feed stream is less than or equal to 10 ppm, based on the mass of the alkane feed stream; preferably, the sulfur content in the alkane feed stream is 2-10 ppm, based on the mass of the alkane feed stream.

[0016] Optionally, the alkane feed stream is one or more of refinery overhead oil, light naphtha, reformer raffinate oil, and Fischer-Tropsch synthesis oil.

[0017] Optionally, the purity of hydrogen used in the first stage desulfurization and / or the second stage desulfurization is above 80% vol, and the sulfur content in the hydrogen is less than 0.05 ppm, based on the mass of the hydrogen.

[0018] Beneficial effects:

[0019] The present application realizes ultra-deep removal of sulfur in hydrocarbon oil by the desulfurization method of hierarchical adsorption-catalysis-adsorption, i.e. removing most of inorganic sulfur in hydrocarbon oil by primary adsorption desulfurization method, then sequentially contacting with sulfur conversion agent and sulfur adsorbent, and sequentially converting organic sulfur into inorganic sulfur and adsorbing inorganic sulfur in the same reaction atmosphere, simultaneously removing inorganic sulfides and organic sulfides in raw materials, so as to reduce the sulfur content in hydrocarbon oil with high sulfur content to below 0.1 ppm or even lower. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 Structure diagram of single-reactor desulfurization reactor used in the desulfurization method of alkanes of the present application;

[0021] Figure 2 Structure diagram of multi-reactor switching reactor used in the desulfurization method of alkanes of the present application;

[0022] Figure 3 Schematic diagram of sulfur content in raw materials at different reaction times in Example 1;

[0023] Figure 4 Schematic diagram of sulfur content in liquid product at different reaction times in Example 1.

[0024] BRIEF DESCRIPTION OF DRAWINGS

[0025] 1 first pipeline; 2 second pipeline; 3 first valve; 4 third pipeline; 5 first reactor; 6 fourth pipeline; 7 third valve; 8 fifth pipeline; 9 sixth pipeline; 10 fourth valve; 11 seventh pipeline; 12 second reactor; 13 eighth pipeline; 14 fifth valve; 15 ninth pipeline; 16 separator; 17 eleventh pipeline; 18 tenth pipeline; 19 twenty-sixth pipeline; 20 sixth valve; 21 twenty-seventh pipeline; 22 twenty-eighth pipeline; 23 seventh valve; 24 twenty-ninth pipeline; 25 twelfth pipeline; 26 eighth valve; 27 thirteenth pipeline; 28 fifteenth pipeline; 29 eleventh valve; 30 sixteenth pipeline; 31 fourteenth pipeline; 32 first hydrogen pipeline; 33 second hydrogen pipeline; 34 second valve; 35 thirtieth pipeline; 36 seventeenth pipeline; 37 ninth valve; 38 nineteenth pipeline; 39 third reactor; 40 twentieth pipeline; 41 tenth valve; 42 twenty-first pipeline; 43 eighteenth pipeline; 44 twenty-third pipeline; 45 thirteenth valve; 46 twenty-fourth pipeline; 47 twenty-fifth pipeline; 48 twelfth valve; 49 thirty-first pipeline. DETAILED DESCRIPTION

[0026] The present application will be further described in detail by the accompanying drawings and examples. Through these descriptions, the features and advantages of the present application will become more apparent.

[0027] The term "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations. Unless specifically indicated otherwise, the drawings are not necessarily to scale.

[0028] In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as there is no conflict.

[0029] The present application provides a desulfurization method of alkane, comprising: contacting an alkane raw material stream with a primary sulfur adsorbent for primary desulfurization to obtain a primary desulfurized stream; contacting the primary desulfurized stream with a sulfur conversion agent and a secondary sulfur adsorbent alternately at least once in the presence of hydrogen for secondary desulfurization; the primary sulfur adsorbent is a bimetallic adsorbent, the primary sulfur adsorbent contains a first metal component and a second metal component, the first metal component is selected from nickel or copper, and the second metal component is selected from manganese or titanium; the sulfur conversion agent is an organic sulfur conversion inorganic sulfur catalyst containing Group VIII metal and metal potassium; and the secondary sulfur adsorbent is an adsorbent containing alkali metal and / or alkaline earth metal metal oxide.

[0030] It should be noted that H2S, mercaptan, sulfide, carbon disulfide and other sulfides may exist in the alkane raw material stream, part of which is inorganic sulfide and part of which is organic sulfide. In the desulfurization method of the present application, most of the inorganic sulfides in the alkane raw material stream are adsorbed and removed when the alkane raw material stream passes through the primary sulfur adsorbent, i.e. the bimetallic adsorbent, and the adsorption and removal process can include physical and chemical adsorption; the hydrocarbon stream after primary adsorption and removal is mixed with hydrogen and then contacted with the sulfur conversion agent and the secondary sulfur adsorbent alternately, first with the sulfur conversion agent, under the catalytic action of the sulfur conversion agent, the organic sulfides in the hydrocarbon stream are converted into inorganic sulfides by reacting with hydrogen, to obtain a hydrocarbon stream containing inorganic sulfides; then, the hydrocarbon stream containing inorganic sulfides is contacted with the secondary sulfur adsorbent, and the inorganic sulfides are adsorbed and removed by the secondary sulfur adsorbent, and the adsorption and removal process can include physical and chemical adsorption.

[0031] In addition, in the desulfurization method of the present application, the primary sulfur adsorbent contains elemental nickel or copper or oxides thereof, and further contains oxides of manganese or titanium; the sulfur conversion agent is an organic sulfur conversion inorganic sulfur catalyst containing Group VIII metal and metallic potassium; and the secondary sulfur adsorbent is an adsorbent containing alkali metal and / or alkaline earth metal oxides. Furthermore, firstly, the alkane raw material stream can be contacted with the primary sulfur adsorbent for multiple times for multiple primary desulfurization; and secondly, the stream after primary desulfurization can be sequentially passed through the sulfur conversion agent and the secondary sulfur adsorbent alternately. In summary, through the sequential and alternate contact with the sulfur conversion agent and the secondary sulfur adsorbent, the organic sulfur is converted into inorganic sulfur, and the generated inorganic sulfur is adsorbed in time, and further, the deep desulfurization can be realized for the alkane raw material stream with relatively high sulfur content, so that the sulfur content in the alkane raw material stream is reduced to below 0.1 ppm or even lower. The sulfur content in the present application can refer to the total content of sulfur in H2S, mercaptans, sulfides, carbon disulfide and other sulfides in the hydrocarbon raw material stream. The sulfur content can be measured by ultraviolet fluorescence detection method.

[0032] Based on a preferred embodiment, the primary desulfurization is performed in a primary desulfurization reactor, and the secondary desulfurization is performed in a secondary desulfurization reactor; and a plurality of groups of the sulfur conversion agent layer and the secondary sulfur adsorbent layer are arranged in the secondary desulfurization reactor. In addition, the inlet of the secondary desulfurization reactor can be close to the sulfur conversion agent layer. In this way, the conversion and adsorption of sulfur can be simultaneously completed in the secondary desulfurization reactor, so that the desulfurization efficiency is better, and the energy consumption is lower.

[0033] Based on an embodiment, the primary desulfurization reactor and the secondary desulfurization reactor are each a plurality of reactors, and the outlet of any one of the primary desulfurization reactors is in fluid communication with the inlet of any one of the secondary desulfurization reactors.

[0034] As a further preferred embodiment, each of the primary desulfurization reactor and the secondary desulfurization reactor is independently provided with a regeneration gas inlet and a regeneration gas outlet. In this way, the nitrogen gas can be conveniently introduced to regenerate the primary sulfur adsorbent in the primary desulfurization reactor and / or the sulfur conversion agent and the secondary sulfur adsorbent in the secondary desulfurization reactor.

[0035] The deactivated sulfur conversion agent and the sulfur adsorbent can be substantially restored to the sulfur removal performance of the adsorbent through simple regeneration operation. The regeneration operation is that the deactivated sulfur conversion agent and / or the sulfur adsorbent are regenerated by blowing N2 at 200-400°C for 2-10 hours, and then can be continuously used, and the desulfurization performance is still 90% of the initial performance.

[0036] Therefore, the deactivated sulfur conversion agent and the sulfur adsorbent can be substantially restored to the desulfurization performance through simple regeneration in the same regeneration atmosphere.

[0037] The primary desulfurization zone can be provided with multiple groups of primary desulfurization reactors that can independently operate, and the secondary desulfurization zone can be provided with multiple groups of secondary desulfurization reactors that can independently operate, so that the adsorption-regeneration switching can be conveniently performed, and the adsorption desulfurization reaction and the regeneration of the adsorbent can be simultaneously performed.

[0038] According to an embodiment, the conditions of the primary desulfurization include a temperature of 100-250°C, a pressure of 0.1-3.0 MPa, a volume space velocity of the feed of 0.5-20 h -1 -1, and a hydrogen / oil volume ratio of 0-100; the conditions of the secondary desulfurization include a temperature of 250-400°C, a pressure of 0.1-2 MPa, a volume space velocity of the feed of 0.5-10 h -1 -1, and a hydrogen / oil volume ratio of 200-2000; preferably, the conditions of the primary desulfurization include a temperature of 150-200°C, a pressure of 0.3-1.0 MPa, a volume space velocity of the feed of 2-10 h -1 -1, and a hydrogen / oil volume ratio of 0-50; the conditions of the secondary desulfurization include a temperature of 280-350°C, a pressure of 0.3-1.0 MPa, a volume space velocity of the feed of 1.0-8.0 h -1 -1, and a hydrogen / oil volume ratio of 200-1000.

[0039] It should be noted that in the desulfurization method of this embodiment, the primary desulfurization poststream is contacted with the sulfur conversion agent and the secondary sulfur adsorbent under the conditions of the secondary desulfurization.

[0040] According to the first embodiment, when the hydrogen / oil volume ratio is 10-100 during the primary desulfurization, the primary sulfur adsorbent includes a carrier and two kinds of metal oxides supported on the carrier, the carrier is Al2O3 and SiO2, the first kind of metal oxide is NiO or CuO, and the second kind of metal oxide is MnO2 or TiO2; the mass ratio of the first kind of metal oxide is 20-50%, the mass ratio of the second kind of metal oxide is 5-15%, the mass ratio of SiO2 is 5-20%, and the mass ratio of Al2O3 is 15-70%; preferably, the mass ratio of the first kind of metal oxide is 30-40%, the mass ratio of the second kind of metal oxide is 5-10%, the mass ratio of SiO2 is 10-15%, and the mass ratio of Al2O3 is 35-55%.

[0041] It should be noted that in the first embodiment, the primary sulfur adsorbent can be NiO-MnO2 / Al2O3-SiO2, NiO-TiO2 / Al2O3-SiO2, CuO-MnO2 / Al2O3-SiO2, or CuO-TiO2 / Al2O3-SiO2, etc.

[0042] Based on the second embodiment, when the volume ratio of hydrogen to oil is 0 during the primary desulfurization, the primary sulfur adsorbent includes a carrier and the first metal component in elemental form and the second metal component in oxide form supported on the carrier, the carrier is Al2O3 and SiO2, the first metal component is Ni or Cu, and the second metal component is MnO2 or TiO2; the mass percentage of the first metal component is 15-35%, the mass percentage of the second metal component is 5-15%, the mass percentage of SiO2 is 5-20%, and the mass percentage of Al2O3 is 30-75%.

[0043] It should be noted that in the second embodiment, the primary sulfur adsorbent can be Ni-MnO2 / Al2O3-SiO2, Ni-TiO2 / Al2O3-SiO2, Cu-MnO2 / Al2O3-SiO2, or Cu-TiO2 / Al2O3-SiO2, etc.

[0044] It should be noted that the primary sulfur adsorbent based on the above-mentioned embodiments can be prepared by a kneading-extrusion method, and the preparation steps are as follows: first, mix and grind a measured amount of 10-500 mesh first metal oxide (nickel oxide powder or copper oxide powder), second metal oxide (manganese oxide powder or titanium dioxide powder), silicon dioxide powder, aluminum hydroxide powder, and sesbania powder into a uniform powder, then add a solution obtained by mixing a measured amount of nitric acid solution, acetic acid solution, and water to the above-mentioned powder, knead uniformly, and then extrude into strips, dry and activate to obtain an oxidized desulfurizer. Alternatively, the primary sulfur adsorbent can also be prepared by an impregnation method, and the preparation steps are as follows: first, mix and grind a measured amount of aluminum hydroxide powder, silicon dioxide powder, second metal oxide (manganese oxide powder or titanium dioxide powder), and sesbania powder into a uniform powder, then add a solution obtained by mixing a measured amount of nitric acid solution, acetic acid solution, and water to the above-mentioned powder, knead uniformly, and then extrude into strips, dry and calcine to obtain strip-shaped carriers, then use a solution containing a nickel or copper compound with a certain appropriate concentration as an impregnation precursor solution to impregnate the above-mentioned carriers in several times, dry and activate, and finally obtain an oxidized primary sulfur adsorbent. The nickel-containing compound can be selected from nickel nitrate, nickel carbonate, and nickel chloride, and nickel carbonate is preferred. The copper-containing compound can be selected from copper nitrate and copper chloride. Drying is carried out in an air atmosphere, the temperature is 80-150°C, and the time is 8-20 hours. Activation is carried out in an air atmosphere, the temperature is 350-650°C, preferably 400-550°C, the gas agent volume ratio is 100-2000, and preferably 500-1000. The oxidized primary sulfur adsorbent can be reduced before use, the reduction is carried out in a dry hydrogen atmosphere, the reduction temperature is 300-550°C, preferably 400-500°C, and the gas agent volume ratio is 200-1500, preferably 400-800.

[0045] According to one embodiment, the sulfur conversion agent comprises a carrier alumina and a Group VIII metal and metal K supported on the carrier alumina, the Group VIII metal being Pt and / or Pd; the mass percentage of the Group VIII metal is 0.2-2% and the mass percentage of metal K is 0.01-0.5% based on the mass of the carrier alumina.

[0046] It should be noted that the sulfur conversion agent can be a Pt-K / Al2O3, Pd-K / Al2O3 or Pt-Pd-K / Al2O3 catalyst, etc.

[0047] It should be noted that the Group VIII metal and alkali metal K in the sulfur conversion agent can be introduced by impregnation, including impregnating the carrier with an impregnation solution containing platinum and / or palladium metal elements, alkali metal K and halogen, and then drying and calcining the impregnated solid to obtain the oxidized state sulfur conversion agent. In the prepared impregnation solution, the platinum metal is from chloroplatinic acid, dichlorotetrakisammine platinum, ammonium chloroplatinate, platinum chloride, tetrahydrate of platinum chloride, dicarbonyl dichloroplatinum, dinitrodiamino platinum or sodium tetranitroplatinic acid; the palladium metal is from palladium chloride or tetrachloropalladic acid; the potassium is from potassium chloride or potassium carbonate; and the halogen is introduced by HCl. The impregnation can be by co-impregnation or by separate impregnation. The impregnation can be by saturation impregnation or by supersaturation impregnation. The liquid / solid volume ratio of the impregnation solution to the carrier during impregnation can be 0.4-4.0, preferably 0.8-2.0. The suitable impregnation temperature is 15-90°C, preferably 20-50°C, and the impregnation time is preferably 1-8 hours, more preferably 2-4 hours. The impregnated solid is dried and calcined in air. The drying temperature is preferably 100-120°C, the calcination temperature is preferably 400-700°C, and the suitable gas / agent volume ratio during calcination is 500-1000:1, and the calcination time is preferably 4-8 hours. The sulfur conversion agent obtained after calcination is in the oxidized state, and the Group VIII metal and K are supported on the carrier in the oxidized state, which needs to be reduced before use. The reduction is carried out in a hydrogen atmosphere, and the suitable reduction temperature is 150-550°C, the gas / agent volume ratio is 400-1400:1, and the reduction time is 2-20 hours, preferably 4-10 hours.

[0048] It should be noted that the shape of the sulfur conversion agent can be spherical, strip-shaped, flaky, granular or clover-shaped, preferably strip-shaped or spherical.

[0049] According to one embodiment, the secondary sulfur adsorbent comprises an inorganic oxide carrier and a metal oxide supported on the inorganic oxide carrier, the inorganic oxide carrier being Al2O3 and / or SiO2, and the metal oxide being an oxide of an alkali metal and / or an alkaline earth metal; the alkali metal being Na or K, and the alkaline earth metal being Ca or Mg; the mass percentage of the metal in the metal oxide is 10-20% based on the mass of the inorganic oxide carrier.

[0050] Based on one embodiment, the secondary sulfur adsorbent is K2O / Al2O3-SiO2 or CaO / Al2O3-SiO2.

[0051] The alkali metal and / or alkaline earth metal of the secondary sulfur adsorbent is introduced by impregnation, including impregnating the carrier with an impregnation solution containing alkali metal and / or alkaline earth metal elements, and then drying and calcining the impregnated solid to obtain the oxidized secondary sulfur adsorbent. In the prepared impregnation solution, the alkali metal and / or alkaline earth metal is from its nitrate salt, chloride salt, carbonate salt, and preferably the carbonate salt. The impregnation can be saturated impregnation or supersaturated impregnation. The liquid / solid volume ratio of the impregnation solution to the carrier during impregnation can be 0.4-4.0, preferably 0.8-2.0. The suitable impregnation temperature is 15-90°C, preferably 20-50°C, and the impregnation time is preferably 1-8 hours, more preferably 2-4 hours. The impregnated solid is dried and calcined in air. The drying temperature is preferably 100-120°C, the calcination temperature is preferably 400-700°C, the suitable gas / agent volume ratio during calcination is 500-1000:1, and the calcination time is preferably 4-8 hours.

[0052] The shape of the secondary sulfur adsorbent can be spherical, strip-shaped, flaky, granular, or clover-shaped, preferably strip-shaped or spherical.

[0053] Based on one embodiment, the alkane raw material stream contains C4-C8 alkanes, and the sulfur content in the alkane raw material stream is less than or equal to 50 ppm based on the mass of the alkane raw material stream. Preferably, the sulfur content in the alkane raw material stream is 0.2-50 ppm based on the mass of the alkane raw material stream. Preferably, the sulfur content in the alkane raw material stream is less than or equal to 10 ppm based on the mass of the alkane raw material stream. Preferably, the sulfur content in the alkane raw material stream is 2-10 ppm based on the mass of the alkane raw material stream.

[0054] It should be noted that the alkane desulfurization method of the present application can achieve very good desulfurization effect on raw materials with a sulfur content of 0.2-50 ppm in the alkane raw material stream, so that the sulfur content in the hydrocarbon oil is reduced to below 0.1 ppm or even lower, that is, very good desulfurization effect can be achieved on raw materials with high sulfur content, and the desulfurization effect is better when the sulfur content in the raw material is reduced.

[0055] Based on one embodiment, the alkane raw material stream is one or more of refinery overhead oil, light naphtha, reforming raffinate, and Fischer-Tropsch synthesis oil.

[0056] Preferably, the light naphtha and the reforming raffinate. The sulfur-containing raw material can be subjected to preliminary refining and fractionation by a pre-hydrogenation and / or fractionation device.

[0057] Based on one embodiment, the hydrogen purity used in the primary desulfurization and / or the secondary desulfurization is above 80%vol; the sulfur content in the hydrogen is less than 0.05ppm based on the mass of the hydrogen. The hydrogen can be cylinder pure hydrogen gas, PSA hydrogen gas or reforming hydrogen.

[0058] It should be noted that the accompanying Figure 1 is a schematic diagram of the structure of the single reactor desulfurization reactor used in the desulfurization method of the present application. The accompanying Figure 1 Two fixed bed reactors are used, one of which is used for primary desulfurization and is packed with primary sulfur adsorbent; the other is used for secondary desulfurization (sulfur conversion and secondary sulfur adsorption) and is packed with sulfur conversion agent-sulfur adsorbent-sulfur conversion agent-sulfur adsorbent... from bottom to top in sequence. The raw material is fed from bottom to top, or the sulfur conversion agent and sulfur adsorbent can be packed from top to bottom in sequence, and the raw material is fed from top to bottom into the reactor accordingly.

[0059] The preheated sulfur-containing light hydrocarbon oil raw material is fed into the first reactor 5 through the first pipeline 1, the second pipeline 2, the first valve 3 and the third pipeline 4, primary sulfur adsorption is carried out, and most of the inorganic sulfur in the hydrocarbon oil raw material is preliminarily removed. This operation is generally carried out under non-hydrogen conditions, or can be carried out under low hydrogen to oil ratio conditions. If it is carried out under low hydrogen to oil ratio conditions, the hydrogen is mixed with the hydrocarbon oil raw material in the second pipeline 2 through the first hydrogen pipeline 32, the second hydrogen pipeline 33, the second valve 34, and then fed into the first reactor 5 through the first valve 3 and the third pipeline 4. The operating conditions of the primary sulfur adsorbent are as follows: temperature 100-200℃, pressure 0.1-3.0MPa, volume space velocity of the feedstock 0.5-20h -1 , hydrogen to oil volume ratio 0-100. After primary sulfur adsorption, the material is fed into the fourth pipeline 6, the third valve 7, the fifth pipeline 8, mixed with hydrogen fed through the first hydrogen pipeline 32 and the thirtieth pipeline 35 in the sixth pipeline 9, fed into the fourth valve 10 and the seventh pipeline 11, and then fed into the second reactor 12, sequentially contacting with the sulfur conversion agent and the secondary sulfur adsorbent in turn, so that the organic sulfur is converted into inorganic sulfur by contacting with the sulfur conversion agent, and then the inorganic sulfur is adsorbed by contacting with the secondary sulfur adsorbent. The operating conditions of the sulfur conversion agent bed and the secondary adsorbent bed are as follows: reaction temperature 250-400℃, reaction pressure 0.1-2.0MPa, volume space velocity 0.5-10h -1 , hydrogen to oil volume ratio 200-2000. After multiple conversion and adsorption, the final reaction stream is sequentially fed into the separator 16 through the eighth pipeline 13, the fifth valve 14 and the ninth pipeline 15, the separated hydrogen-containing gas is discharged out of the device through the tenth pipeline 18, and the liquid product, i.e. the product with ultra-low sulfur content, is introduced into the downstream device or container through the eleventh pipeline 17.

[0060] When the primary sulfur adsorbent in the first reactor 5 becomes deactivated, the first valve 3 is closed to stop the feed, and the third valve 7 is closed to shut down the first reactor 5. The sixth valve 20 and the eighth valve 26 are opened, and nitrogen gas is introduced into the first reactor 5 via the twenty-sixth pipeline 19, the sixth valve 20, the twenty-seventh pipeline 21, and the third pipeline 4 to purge the reactor. After the reaction stream in the first reactor 5 is emptied, the primary sulfur adsorbent in the first reactor 5 is regenerated under the following conditions: temperature 200–400℃, preferably 250–350℃; time 2–10 hours, preferably 4–6 hours; pressure 0.1–1.0 MPa, preferably 0.3–0.6 MPa. The regenerated flue gas is then sequentially led out of the device via the twelfth pipeline 25, the eighth valve 26, the thirteenth pipeline 27, and the fourteenth pipeline 31.

[0061] When the sulfur conversion agent and secondary sulfur adsorbent in the second reactor 12 are deactivated, the fourth valve 10 is closed to stop the feed. After the reaction stream in the second reactor 12 is emptied, the fifth valve 14 is closed, and the second reactor 12 is shut down. Then, the seventh valve 23 and the eleventh valve 29 are opened to regenerate the sulfur conversion agent and secondary sulfur adsorbent in the second reactor 12. Similar to the regeneration of the primary adsorbent, nitrogen gas is introduced into the second reactor 12 via the twenty-eighth pipeline 22, the seventh valve 23, the twenty-ninth pipeline 24, and the seventh pipeline 11, and sequentially contacts the intermittently packed sulfur conversion agent and secondary sulfur adsorbent for regeneration. The regeneration conditions are as follows: temperature 200–400℃, preferably 250–350℃; time 2–10 hours, preferably 4–6 hours; pressure 0.1–1.0 MPa, preferably 0.3–0.6 MPa. The regenerated flue gas is sequentially led out of the device via the fifteenth pipeline 28, the eleventh valve 29, the sixteenth pipeline 30, and the fourteenth pipeline 31.

[0062] Appendix Figure 2 This is a schematic diagram of the multi-reactor switching reactor used in the alkane desulfurization method of the present invention. Figure 2 Three fixed-bed reactors are employed. One reactor is used for primary sulfur adsorption, and is filled with primary sulfur adsorbent. The other two reactors are used for sulfur conversion reaction and secondary sulfur adsorption. These two reactors can be switched, with one reactor used for reactive adsorption and the other for regeneration. The reactors are filled sequentially from bottom to top with sulfur conversion agent-sulfur adsorbent-sulfur conversion agent-sulfur adsorbent… The feed material is fed from bottom to top, or it can be filled sequentially from top to bottom with sulfur conversion agent and sulfur adsorbent, with the feed material entering the reactor from the top accordingly. In practical applications, three or more reactors can be used.

[0063] The preheated sulfur-containing light hydrocarbon oil feedstock is introduced into the first reactor 5 through the first pipeline 1, the second pipeline 2, the first valve 3 and the third pipeline 4, and subjected to primary sulfur adsorption to preliminarily remove most of the inorganic sulfur in the hydrocarbon oil feedstock. The operation is generally carried out under non-hydrogen condition, or can be carried out under low hydrogen to oil ratio condition. If the operation is carried out under low hydrogen to oil ratio condition, the hydrogen is mixed with the hydrocarbon oil feedstock in the second pipeline 2 through the first hydrogen pipeline 32, the second hydrogen pipeline 33 and the second valve 34, and then introduced into the first reactor 5 through the first valve 3 and the third pipeline 4. The operation conditions of the primary sulfur adsorbent are as follows: temperature 100-200°C, pressure 0.1-3.0 MPa, volume space velocity of the feedstock 0.5-20 h -1 , hydrogen to oil volume ratio 0-100. After the primary sulfur adsorption, the material is introduced into the second reactor 12 through the fourth pipeline 6, the third valve 7, the fifth pipeline 8, mixed with hydrogen through the first hydrogen pipeline 32 and the thirtieth pipeline 35 in the sixth pipeline 9, introduced into the second reactor 12 through the seventeenth pipeline 36, the fourth valve 10 and the seventh pipeline 11, and sequentially contacted with the interval-packed sulfur conversion agent and the secondary sulfur adsorbent to convert the organic sulfur compounds in the material into inorganic sulfur compounds through the sulfur conversion agent, and then contacted with the secondary sulfur adsorbent to adsorb the generated inorganic sulfur compounds in time. The operation conditions of the sulfur conversion agent bed and the secondary adsorbent bed are as follows: temperature 250-400°C, pressure 0.1-2.0 MPa, volume space velocity of the feedstock 0.5-10 h -1 , hydrogen to oil volume ratio 200-2000. After the multiple conversion and adsorption, the final reaction stream is introduced into the separator 16 through the eighth pipeline 13, the fifth valve 14, the ninth pipeline 15 and the eighteenth pipeline 43, the separated hydrogen-containing gas is discharged out of the device through the tenth pipeline 18, and the liquid product, i.e. the liquid product with ultra-low sulfur content, is introduced into the downstream device or container through the eleventh pipeline 17.

[0064] When the primary sulfur adsorbent in the first reactor 5 is deactivated, the first valve 3 is closed to stop the feedstock, the third valve 7 is closed, and the first reactor 5 is disabled. The sixth valve 20 and the eighth valve 26 are opened, and nitrogen is introduced into the first reactor 5 through the twenty-sixth pipeline 19, the sixth valve 20, the twenty-seventh pipeline 21 and the third pipeline 4 to purge the first reactor 5. After the reaction stream in the first reactor 5 is purged, the primary sulfur adsorbent in the first reactor 5 is regenerated. The regeneration conditions are as follows: temperature 200-400°C, preferably 250-350°C, time 2-10 hours, preferably 4-6 hours, pressure 0.1-1.0 MPa, preferably 0.3-0.6 MPa. The flue gas after the regeneration is introduced out of the device through the twelfth pipeline 25, the eighth valve 26, the thirteenth pipeline 27 and the fourteenth pipeline 31.

[0065] When the sulfur conversion catalyst and secondary sulfur adsorbent in the second reactor 12 are deactivated, the fourth valve 10 is closed to stop the feed, and the fifth valve 14 is closed after the reaction stream in the second reactor 12 is exhausted, and the second reactor 12 is deactivated. At the same time, the ninth valve 37 and the tenth valve 41 are opened, and the third reactor 39 is switched to perform the sulfur conversion and adsorption. Then the seventh valve 23 and the eleventh valve 29 are opened, and the sulfur conversion catalyst and secondary sulfur adsorbent in the second reactor 12 are regenerated. As the primary adsorbent regeneration, nitrogen is used to enter the second reactor 12 through the twenty-eighth pipeline 22, the seventh valve 23, the twenty-ninth pipeline 24, and the seventh pipeline 11, and sequentially contacts the interval-packed sulfur conversion catalyst and secondary sulfur adsorbent for regeneration. The regeneration conditions are as follows: the temperature is 200-400°C, preferably 250-350°C, the time is 2-10 hours, preferably 4-6 hours, and the pressure is 0.1-1.0 MPa, preferably 0.3-0.6 MPa. The flue gas after regeneration is sequentially led out of the device through the fifteenth pipeline 28, the eleventh valve 29, the sixteenth pipeline 30, and the fourteenth pipeline 31.

[0066] At the same time when the sulfur conversion catalyst and secondary sulfur adsorbent in the second reactor 12 are regenerated, the hydrocarbon oil material after the primary sulfur adsorption desulfurization is mixed with hydrogen gas from the first hydrogen gas through the pipeline 32 and the thirtieth pipeline 35 in the sixth pipeline 9, and is sequentially introduced into the third reactor 39 through the seventeenth pipeline 36, the ninth valve 37, and the nineteenth pipeline 38, and is alternately contacted with the interval-packed sulfur conversion catalyst and secondary sulfur adsorbent, so that the organic sulfides in the material are converted into inorganic sulfides under the action of the sulfur conversion catalyst, and then are contacted with the secondary sulfur adsorbent, and the generated inorganic sulfur is timely adsorbed. The operating conditions of the sulfur conversion catalyst bed and the secondary adsorbent bed are as follows: the temperature is 250-400°C, the pressure is 0.1-2.0 MPa, the volume space velocity of the feed is 0.5-10 h -1 , and the hydrogen-oil volume ratio is 200-2000. After multiple conversions and adsorptions, the last reaction stream is sequentially introduced into the separator 16 through the twentieth pipeline 40, the tenth valve 41, the twenty-first pipeline 42, and the eighteenth pipeline 43, the separated hydrogen-containing gas is led out of the device through the tenth pipeline 18, and the liquid product, i.e., the product with ultra-low sulfur content, is introduced into the downstream device or container through the eleventh pipeline 17.

[0067] When the sulfur conversion agent and the secondary sulfur adsorbent in the third reactor 39 are deactivated, the ninth valve 37 is closed to stop the feed, and after the stream in the third reactor 39 is exhausted, the tenth valve 41 is closed to stop the third reactor 39. At the same time, the fourth valve 10 and the fifth valve 14 are opened to switch to the second reactor 12 to repeat the above-mentioned conversion, adsorption and product separation processes. At the same time, the twelfth valve 48 and the thirteenth valve 45 are opened to regenerate the sulfur conversion agent and the secondary sulfur adsorbent in the third reactor 39. Nitrogen gas enters the third reactor 39 through the twenty-fifth pipeline 47, the twelfth valve 48, the thirty-first pipeline 49 and the nineteenth pipeline 38 in sequence, and is regenerated by sequentially contacting the interval-packed sulfur conversion agent and the sulfur adsorbent. The regeneration conditions are as follows: the temperature is 200-400°C, preferably 250-350°C; the time is 2-10 hours, preferably 4-6 hours; the pressure is 0.1-1.0 MPa, preferably 0.3-0.6 MPa; and the gas agent volume ratio is 200-800. The regenerated flue gas is led out of the device through the twenty-third pipeline 44, the thirteenth valve 45, the twenty-fourth pipeline 46, the sixteenth pipeline 30 and the fourteenth pipeline 31 in sequence.

[0068] The application will be further described below by examples, but the application is not limited thereto.

[0069] Example 1

[0070] (1) Preparation of the primary sulfur adsorbent:

[0071] 30 grams of NiO powder, 10 grams of MnO2 powder, 66 grams of aluminum hydroxide powder (with an Al2O3 content of 76 mass%), 10 grams of silicon oxide powder and 2 grams of sesbania powder were uniformly mixed and ground, 1 milliliter of 65 mass% nitric acid and 2 milliliters of 36% acetic acid were added to 70 milliliters of water to dissolve to obtain a peptizing agent solution, and then the solution was added to the above-mentioned mixed powder, which was uniformly kneaded, then extruded, and the wet strip was dried at 120°C for 12 hours and calcined at 500°C for 4 hours to prepare a sulfur adsorbent. The content of NiO in the sulfur adsorbent was 30 mass% and the content of MnO2 was 10 mass% based on the mass of the dry sulfur adsorbent. The obtained primary sulfur adsorbent is denoted as DSA-1.

[0072] (2) Preparation of the sulfur conversion agent:

[0073] 100 grams of aluminum hydroxide powder prepared by the alkoxy hydrolysis method (with an Al2O3 content of 76 mass%) were uniformly kneaded according to the mass ratio of aluminum hydroxide powder: sesbania powder: 65% nitric acid: 36% acetic acid: water = 50:1:1:2:40, then extruded, and the wet strip was dried at 120°C for 12 hours and calcined at 550°C for 4 hours to prepare a γ-Al2O3 carrier.

[0074] Take 30 grams of γ-Al2O3 carrier, and prepare an impregnation solution from chloroplatinic acid, palladium chloride, potassium chloride and hydrochloric acid, so that the Pt content in the impregnation solution is 0.2 mass%, the Pd content is 0.1 mass%, the K content is 0.1 mass%, and the Cl content is 1.8 mass% (relative to the mass of the dry base alumina carrier), and the liquid / solid volume ratio is 1.5. After impregnation at normal pressure and room temperature for 3 hours, the impregnated carrier is dried to dryness at 70°C and 0.008 MPa, then dried at 120°C for 12 hours, calcined in air at 500°C and a gas / agent volume ratio of 700 for 4 hours, cooled to 150°C, replaced with hydrogen after nitrogen replacement, then reduced with hydrogen at 400°C and a gas / agent volume ratio of 500 for 2 hours, to obtain a sulfur conversion agent, wherein the Pt content is 0.2 mass%, the Pd content is 0.1 mass%, the K content is 0.1 mass%, and the Cl content is 1.0 mass% based on the dry base Al2O3 carrier. The obtained sulfur conversion agent is denoted as STR.

[0075] (3) Preparation of secondary sulfur adsorbent:

[0076] Take 92 grams of aluminum hydroxide powder prepared by the alkoxy hydrolysis method (with an Al2O3 content of 76 mass%), and 30 grams of silica powder. Mix the above-mentioned aluminum hydroxide powder and silica powder to obtain a powder. Then, uniformly mix the powder according to the mass ratio of powder: sesbania powder: 65% nitric acid: 36% acetic acid: water = 50: 1: 1: 2: 40, and then extrude into a strip. The wet strip is dried at 120°C for 12 hours and calcined at 600°C for 4 hours to obtain an Al2O3-SiO2 carrier.

[0077] Take 30 grams of Al2O3-SiO2 carrier, and prepare an impregnation solution from potassium carbonate, so that the K content in the impregnation solution is 15 mass% (relative to the mass of the dry base Al2O3-SiO2), and the liquid / solid volume ratio is 1.5. After impregnation at normal pressure and room temperature for 3 hours, the impregnated carrier is dried to dryness at 70°C and 0.008 MPa, then dried at 120°C for 12 hours, and calcined in air at 450°C and a gas / agent volume ratio of 700 for 4 hours to obtain a sulfur adsorbent II, wherein the K content is 15 mass% based on the mass of the dry base Al2O3-SiO2 carrier. The obtained secondary sulfur adsorbent is denoted as DSB-1.

[0078] (4) The single reactor desulfurization reactor of the present application is used to perform ultra-deep desulfurization of light alkanes. Figure 1 The single reactor desulfurization reactor of the present application is used to perform ultra-deep desulfurization of light alkanes.

[0079] The primary sulfur adsorbent DSA-1 was reduced in a hydrogen atmosphere at 400°C for 4 hours with a gas / adsorbent volume ratio of 600 to reduce the NiO to Ni. 16 grams of the reduced primary sulfur adsorbent DSA-1 was packed into the first reactor. Two portions of 2.5 grams of sulfur transfer agent STR and two portions of 5 grams of secondary sulfur adsorbent DSB-1 were weighed and packed into the second reactor in the order of sulfur transfer agent-sulfur adsorbent-sulfur transfer agent-sulfur adsorbent (the second reactor included two groups of sulfur transfer agent and two groups of secondary sulfur adsorbent).

[0080] The feedstock A was used as the alkane feed stream and its composition is shown in Table 1. The feedstock A was first contacted with the primary sulfur adsorbent in the first reactor in a small fixed bed reactor and the effluent was then contacted with the sulfur transfer agent and the sulfur adsorbent in the second reactor in an alternating manner for catalytic conversion and adsorption. The main operating conditions for the first reactor were: a reaction temperature of 150°C, a reaction pressure of 0.5 MPa, a volume space velocity of 8 h"1and a hydrogen / oil volume ratio of 600. The effluent from the top of the first reactor was introduced into the second reactor and the main operating conditions for the second reactor were: a reaction temperature of 350°C, a reaction pressure of 0.5 MPa, a volume space velocity of 8 h"1and a hydrogen / oil volume ratio of 600. The product from the top of the second reactor was cooled and separated to obtain the gaseous product and the liquid product. The liquid product yield and the sulfur removal efficiency were calculated by measuring the cumulative amount of the feed and the product in the same period of time (2 hours) respectively: -1 -1

[0081] Liquid product yield / % = mass of liquid product ÷ mass of feedstock feed x 100%;

[0082] Sulfur removal efficiency = (sulfur content of feedstock - sulfur content of product) ÷ sulfur content of feedstock x 100%;

[0083] The sulfur content was measured by ultraviolet fluorescence detection method.

[0084] The composition distribution of the feedstock and the product, the sulfur content and the liquid product yield data are shown in Table 1. It can be seen from Table 1 that the sulfur in the feedstock can be removed to below 0.1 ppm in 300 hours of reaction and the liquid product yield is greater than 98.5%, indicating that the loss of the feedstock is small after the staged sulfur removal.

[0085] After 300 h, the sulfur content of the feedstock was increased to 100 ppm by adding allyl methyl sulfide and the sulfur removal test was continued. Figure 1 is a graph showing the sulfur content in the feedstock at different reaction times. Figure 2 is a graph showing the sulfur content in the liquid product at different reaction times. The sulfur content in the liquid product was 0.09 ppm at 830 h and the sulfur content in the liquid product was 0.13 ppm at 860 h. Figure 3 Figure 4 ​​​​

[0086] Table 1

[0087]

[0088] Example 2

[0089] Using the appendix of this invention Figure 1 A single-reactor desulfurization reactor is used for ultra-deep desulfurization of light alkanes.

[0090] The deactivated primary sulfur adsorbent DSA-1, sulfur conversion agent STR, and secondary sulfur adsorbent DSB-1 from Example 1 were regenerated. The regeneration conditions were: regeneration temperature 300°C, nitrogen purging for 4 hours, pressure 0.5 MPa, and gas-to-adsorbent volume ratio of 500.

[0091] After the primary sulfur adsorbent, sulfur converter, and secondary sulfur adsorbent are regenerated, raw material A is used to sequentially contact the regenerated primary sulfur adsorbent, sulfur converter, and secondary sulfur adsorbent. The process and main operating conditions are the same as in Example 1. The composition distribution and sulfur content data of the raw materials and products are shown in Table 2. As can be seen from Table 2, the performance of the regenerated adsorbent is basically restored, and the sulfur in the raw material can be removed to below 0.1 ppm within 300 hours of reaction.

[0092] Table 2

[0093]

[0094] Example 3

[0095] Using the appendix of this invention Figure 1 A single-reactor desulfurization reactor is used for ultra-deep desulfurization of light alkanes.

[0096] 16 grams of primary sulfur adsorbent DSA-1 were loaded into the first reactor. Two 2.5-gram portions of sulfur conversion agent STR and two 5-gram portions of secondary sulfur adsorbent DSB-1 were weighed and loaded into the second reactor in a sulfur conversion agent-sulfur adsorbent-sulfur conversion agent-sulfur adsorbent manner. The primary sulfur adsorbent DSA-1, sulfur conversion agent STR, and secondary sulfur adsorbent DSB-1 were prepared in Example 1.

[0097] Raw material A is first contacted with a primary sulfur adsorbent in a small fixed-bed reactor. The effluent is then alternately contacted with a sulfur converter and a sulfur adsorbent in a second reactor for catalytic sulfur conversion and adsorption. The main operating conditions of the first reactor are: reaction temperature 150℃, reaction pressure 0.5MPa, and volumetric hourly space velocity (VHSV) 4 h⁻¹. -1 The hydrogen-to-oil volume ratio is 50. The stream exiting from the top of the first reactor enters the second reactor. The main operating conditions of the second reactor are: reaction temperature 350℃, reaction pressure 0.35MPa, and volume hourly space velocity (VHSV) 4 h⁻¹. -1The hydrogen-to-oil volume ratio was 600. The product obtained from the top of the second reactor was cooled and separated into gaseous and liquid products. The reaction conditions and results are shown in Table 3. As can be seen from Table 3, sulfur in the feedstock can be removed to below 0.1 ppm after 300 h of reaction.

[0098] Example 4

[0099] Using the appendix of this invention Figure 1 A single-reactor desulfurization reactor is used for ultra-deep desulfurization of light alkanes.

[0100] 16 grams of the primary sulfur adsorbent DSA-1, reduced according to the reduction step in Example 1, were loaded into the first reactor. Two 2.5-gram portions of sulfur conversion agent STR and two 5-gram portions of secondary sulfur adsorbent DSB-1 were weighed and loaded into the second reactor in the order of sulfur conversion agent-sulfur adsorbent-sulfur conversion agent-sulfur adsorbent. The primary sulfur adsorbent DSA-1, sulfur conversion agent STR, and secondary sulfur adsorbent DSB-1 were prepared in Example 1.

[0101] Raw material A is first contacted with DSA-1 in the first reactor of a small fixed-bed reactor. The outflowing material is then alternately contacted with STR and DSB-1 in the second reactor for sulfur catalytic conversion and adsorption. The main operating conditions of the first reactor are: reaction temperature 180℃, reaction pressure 0.35MPa, and volume hourly space velocity 4 h⁻¹. -1 The stream exiting from the top of the first reactor enters the second reactor. The main operating conditions are: reaction temperature 300℃, reaction pressure 0.35MPa, and volume hourly space velocity (VHSV) 4 h⁻¹. -1 The hydrogen-to-oil volume ratio was 800. The product obtained from the top of the second reactor was cooled and separated into gaseous and liquid products. The reaction conditions and results are shown in Table 3. As can be seen from Table 3, sulfur in the feedstock can be removed to below 0.1 ppm after 300 h of reaction.

[0102] Table 3

[0103]

[0104]

[0105] Example 5

[0106] Using the appendix of this invention Figure 2 Multi-reactor switching reactor for ultra-deep desulfurization of light alkanes.

[0107] The first reactor was filled with 16 grams of primary sulfur adsorbent DSA-1, which had been reduced by the reduction step in Example 1. The subsequent two reactors (the second and third reactors) were filled sequentially in a sulfur conversion agent-sulfur adsorbent-sulfur conversion agent-sulfur adsorbent configuration, with 4 grams of sulfur conversion agent STR, 4 grams of secondary sulfur adsorbent DSB-1, 4 grams of sulfur conversion agent STR, and 4 grams of secondary sulfur adsorbent DSB-1 added to each reactor. Each reactor contained a total of 8 grams of sulfur conversion agent STR and 8 grams of secondary sulfur adsorbent DSB-1. The primary sulfur adsorbent DSA-1, sulfur conversion agent STR, and secondary sulfur adsorbent DSB-1 were prepared in Example 1.

[0108] Raw material B (Table 4) is first contacted with DSA-1 in the first reactor of a small fixed-bed reactor. The effluent is then alternately contacted with STR and DSB-1 in the second reactor for sulfur catalytic conversion and adsorption. The main operating conditions of the first reactor are: reaction temperature 150℃, reaction pressure 0.5MPa, and volume hourly space velocity 8 h⁻¹. -1 The stream exiting from the top of the first reactor enters the second reactor. The main operating conditions are: reaction temperature 350℃, reaction pressure 0.5MPa, and volume hourly space velocity (VHSV) 8 h⁻¹. -1 The hydrogen-to-oil volume ratio was 600. The product obtained from the top of the second reactor was cooled and separated into gaseous and liquid products. After 500 hours of reaction, the second reactor was switched to the third reactor. The composition distribution and sulfur content data of the feedstock and the product after 300 hours of reaction are shown in Table 4. As can be seen from Table 4, sulfur in the feedstock can be removed to below 0.1 ppm after 300 hours of reaction.

[0109] Table 4

[0110]

[0111]

[0112] Example 6

[0113] (1) Take 30 g of CuO powder, 10 g of TiO2 powder, 66 g of aluminum hydroxide powder (of which Al2O3 content is 76% by mass), 10 g of silica powder and 2 g of guar gum powder, mix and grind them evenly. Take 1 ml of 65% by mass nitric acid and 2 ml of 36% acetic acid and add them to 70 ml of water to dissolve them to obtain a colloidal solution. Then add this solution to the above mixed powder, knead evenly, and then extrude it into strips. Dry the wet strips at 120℃ for 12 hours and calcine at 500℃ for 4 hours to obtain a sulfur adsorbent. The dry basis sulfur adsorbent has a CuO content of 30% by mass and a TiO2 content of 10% by mass. The obtained primary sulfur adsorbent is denoted as DSA-2.

[0114] (2) 92 g of aluminum hydroxide powder (Al203 content: 76 mass%) prepared by the alkoxyl hydrolysis method, 30 g of silica powder, and the above-mentioned aluminum hydroxide powder and silica powder were mixed to obtain a powder. The powder was mixed with husked sorgo powder, 65% nitric acid, 36% acetic acid, and water at a mass ratio of 50:1:1:2:40, and then kneaded uniformly. The kneaded product was extruded into a strip, and the wet strip was dried at 120°C for 12 hours and then calcined at 600°C for 4 hours to obtain an Al203-Si02 carrier.

[0115] 30 g of the Al203-Si02 carrier was impregnated with an impregnation solution prepared by dissolving sodium carbonate in water so that the Na content in the impregnation solution was 15 mass% (with respect to the mass of the dry Al203-Si02 carrier) and the liquid / solid volume ratio was 1.5. After impregnation at normal pressure and room temperature for 3 hours, the impregnated carrier was dried at 70°C under reduced pressure to a dry state, and then dried at 120°C for 12 hours. The dried carrier was calcined in an air atmosphere at 450°C for 4 hours under a gas / agent volume ratio of 700 to obtain a sulfur adsorbent II in which the Na content was 15 mass% with respect to the dry Al203-Si02 carrier. The obtained secondary sulfur adsorbent is referred to as DSB-2.

[0116] (3) The light alkane was subjected to ultra-deep desulfurization using the single reactor desulfurization reactor according to the present application. Figure 1

[0117] The primary sulfur adsorbent DSA-2 was reduced according to the reduction procedure of the primary sulfur adsorbent of Example 1 to reduce CuO to Cu, and 16 g of the reduced primary sulfur adsorbent DSA-2 was loaded into the first reactor. Two portions of 2.5 g of the sulfur conversion agent STR and two portions of 5 g of the secondary sulfur adsorbent DSB-2 were weighed, and loaded into the second reactor in the order of sulfur conversion agent-sulfur adsorbent-sulfur conversion agent-sulfur adsorbent. The conversion agent STR was prepared according to Example 1.

[0118] The same raw material, operating conditions, and procedure as in Example 1 were used to perform a sulfur removal test. The sulfur content of the product after 300 hours of reaction was 0.06 ppm, the sulfur removal rate was 99.88%, and the liquid product yield was 99.06%.

[0119] Comparative Example 1

[0120] The raw material of Comparative Example 1 was the same as that of Example 1, and the raw material was contacted with only the reduced primary sulfur conversion agent DSA-1 obtained in Example 1 in a small fixed bed reactor. The main operating conditions were as follows: reaction temperature: 150°C, reaction pressure: 0.5 MPa, and volume space velocity: 8 hours -1 The sulfur content of the product after desulfurization for 300 hours is shown in Table 3.

[0121] Comparative Example 2

[0122] ​The raw materials of Comparative Example 2 were the same as those of Example 1. The raw materials were first contacted with the reduced first-stage sulfur conversion agent DSA-1 of Example 1 in a first reactor, and the effluent was only contacted with STR in a second reactor in a small fixed-bed reactor. The specific test procedure was the same as that of Example 1, and the main operating conditions were the same as those of Example 1. The sulfur content of the product after 300 h of desulfurization is shown in Table 3.

[0123] Comparative Example 3

[0124] A nickel-based adsorbent, denoted as R-DS, was prepared by mixing according to the method provided in US5322615, wherein the content of Ni was 56%, the content of SiO2 was 33%, and the content of Al2O3 was 11%. A sulfur conversion agent Pt / Al2O3, denoted as R-ST, was prepared by impregnation using alumina produced by Changling as the carrier, wherein the content of Pt was 0.2% based on the mass of the carrier. A K / Al2O3 was prepared by impregnation using alumina produced by Changling as the carrier, wherein the content of K was 10% as a potassium-containing sulfur adsorbent based on the mass of the carrier, denoted as R-DSK.

[0125] The sulfur removal test was performed using the same scheme, raw materials, flow and operating parameters as those of Example 1. The test results (after 300 h of reaction) are shown in Table 3. It was found that the sulfur removal rate and the liquid product yield were both lower compared with Example 1.

[0126] In the description of the present application, it should be noted that the terms "upper", "lower", "inner", "outer", "front", "back", "left", "right" and the like indicate the orientation or positional relationship based on the working state of the present application, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0127] In the description of the present application, it should be noted that the terms "mounting", "connecting", "connection" should be understood in a broad sense unless otherwise specifically defined and limited. The specific meanings of the above terms in the present application can be understood by those skilled in the art according to the specific circumstances.

[0128] The above describes the present application in combination with the preferred embodiments, but these embodiments are only exemplary and serve only to illustrate. On this basis, various substitutions and improvements can be made to the present application, and these all fall within the scope of protection of the present application.

Claims

1. A method for desulfurizing alkanes, characterized in that, include: The alkane feedstock stream is brought into contact with a primary sulfur adsorbent to perform primary desulfurization, resulting in a primary desulfurized stream. In the presence of hydrogen, the post-desulfurization stream is subjected to secondary desulfurization by alternating contact with the sulfur conversion agent and the secondary sulfur adsorbent at least once; The primary sulfur adsorbent is a bimetallic adsorbent containing a first metal component and a second metal component, wherein the first metal component is selected from nickel or copper, and the second metal component is selected from manganese or titanium; the sulfur conversion agent is an organic sulfur to inorganic sulfur catalyst containing Group VIII metals and potassium metal; the secondary sulfur adsorbent is an adsorbent containing metal oxides of alkali metals and / or alkaline earth metals. The alkane feed stream contains C4-C8 alkanes, and the sulfur content in the alkane feed stream is less than or equal to 50 ppm, based on the mass of the alkane feed stream; The primary desulfurization is carried out in a primary desulfurization reactor, the secondary desulfurization is carried out in a secondary desulfurization reactor, and the primary desulfurization reactor is a fixed-bed reactor; The temperature for the primary desulfurization condition is 100~180℃.

2. The desulfurization method according to claim 1, characterized in that, The secondary desulfurization reactor is provided with multiple sets of spaced sulfur conversion agent layers and secondary sulfur adsorbent layers, and the inlet of the secondary desulfurization reactor is close to the sulfur conversion agent layer.

3. The desulfurization method according to claim 2, characterized in that, There are multiple primary desulfurization reactors and multiple secondary desulfurization reactors, and the outlet of any one of the primary desulfurization reactors is in fluid communication with the inlet of any one of the secondary desulfurization reactors.

4. The desulfurization method according to claim 2, characterized in that: The conditions for the primary desulfurization include: pressure 0.1~3.0 MPa, and feed volume hourly space velocity 0.5~20 h⁻¹. -1 The hydrogen-to-oil volume ratio is 0~100; The conditions for the secondary desulfurization include: temperature 250~400℃, pressure 0.1~2 MPa, and feed volume hourly space velocity 0.5~10 h⁻¹. -1 The hydrogen-to-oil volume ratio is 200-2000.

5. The desulfurization method according to claim 4, characterized in that, The conditions for the primary desulfurization include: temperature 150~200℃, pressure 0.3~1.0MPa, and feed volumetric space velocity 2~10 h⁻¹. -1 The hydrogen-to-oil volume ratio is 0-50; the conditions for the secondary desulfurization include: temperature 280-350℃, pressure 0.3-1.0 MPa, and feed volume hourly space velocity 1.0-8.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 200-1000.

6. The desulfurization method according to claim 4 or 5, characterized in that, When performing the first-stage desulfurization, if the hydrogen-to-oil volume ratio is 10-100, the first-stage sulfur adsorbent includes a support and two metal oxides supported on the support. The support is Al2O3 and SiO2, the first metal oxide is NiO or CuO, and the second metal oxide is MnO2 or TiO2. Based on the mass of the primary sulfur adsorbent, the mass percentage of the first metal oxide is 20-50%, the mass percentage of the second metal oxide is 5-15%, the mass percentage of SiO2 is 5-20%, and the mass percentage of Al2O3 is 15-70%.

7. The desulfurization method according to claim 6, characterized in that, Based on the mass of the primary sulfur adsorbent, the mass percentage of the first metal oxide is 30-40%, the mass percentage of the second metal oxide is 5-10%, the mass percentage of SiO2 is 10-15%, and the mass percentage of Al2O3 is 35-55%.

8. The desulfurization method according to claim 4 or 5, characterized in that, When performing the first-stage desulfurization, if the hydrogen-to-oil volume ratio is 0, the first-stage sulfur adsorbent includes a support and a first metal component in elemental form and a second metal component in oxide form supported on the support. The support is Al2O3 and SiO2, the first metal component is Ni or Cu, and the second metal component is MnO2 or TiO2. Based on the mass of the primary sulfur adsorbent, the mass percentage of the first metal component is 15-35%, the mass percentage of the second metal component is 5-15%, the mass percentage of SiO2 is 5-20%, and the mass percentage of Al2O3 is 30-75%.

9. The desulfurization method according to claim 6, characterized in that, The sulfur conversion agent comprises an alumina support and a Group VIII metal and a metal K supported on the alumina support, wherein the Group VIII metal is Pt and / or Pd; Based on the mass of the carrier alumina, the mass percentage of the Group VIII metal is 0.2-2%, and the mass percentage of metal K is 0.01-0.5%.

10. The desulfurization method according to claim 7, characterized in that, The sulfur conversion agent comprises an alumina support and a Group VIII metal and a metal K supported on the alumina support, wherein the Group VIII metal is Pt and / or Pd; Based on the mass of the carrier alumina, the mass percentage of the Group VIII metal is 0.2-2%, and the mass percentage of metal K is 0.01-0.5%.

11. The desulfurization method according to claim 8, characterized in that, The sulfur conversion agent comprises an alumina support and a Group VIII metal and a metal K supported on the alumina support, wherein the Group VIII metal is Pt and / or Pd; Based on the mass of the carrier alumina, the mass percentage of the Group VIII metal is 0.2-2%, and the mass percentage of metal K is 0.01-0.5%.

12. The desulfurization method according to any one of claims 9 to 11, characterized in that, The secondary sulfur adsorbent comprises an inorganic oxide support and a metal oxide supported on the inorganic oxide support. The inorganic oxide support is Al2O3 and / or SiO2, and the metal oxide is an oxide of an alkali metal and / or an alkaline earth metal. The alkali metal is Na or K, and the alkaline earth metal is Ca or Mg. Based on the mass of the inorganic oxide carrier, the mass percentage of metal in the metal oxide is 10-20%.

13. The desulfurization method according to claim 12, characterized in that, The secondary sulfur adsorbent is K2O / Al2O3-SiO2 or CaO / Al2O3-SiO2.

14. The desulfurization method according to claim 1, characterized in that, The sulfur content in the alkane feedstock is 0.2-50 ppm, based on the mass of the alkane feedstock.

15. The desulfurization method according to claim 1, characterized in that, The sulfur content in the alkane feedstock is less than or equal to 10 ppm, based on the mass of the alkane feedstock.

16. The desulfurization method according to claim 1, characterized in that, The sulfur content in the alkane feedstock stream is 2-10 ppm, based on the mass of the alkane feedstock stream.

17. The desulfurization method according to any one of claims 1, 14-16, characterized in that, The alkane feedstock stream is one or more of the following: refinery overhead oil, light naphtha, reformate residue, and Fischer-Tropsch synthetic oil.

18. The desulfurization method according to claim 17, characterized in that, The hydrogen used in the primary desulfurization and / or the secondary desulfurization has a purity of 80% vol or higher; the sulfur content in the hydrogen is less than 0.05 ppm, based on the mass of the hydrogen.

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